










                         SENDMAILTM

              INSTALLATION AND OPERATION GUIDE

                        Eric Allman
                       Claus Assmann
                    Gregory Neil Shapiro
                       Sendmail, Inc.

                       Version 8.751

                 For Sendmail Version 8.14




     SendmailTM implements a  general  purpose  internetwork
mail  routing  facility  under the UNIX(R) operating system.
It is not tied to any one transport protocol -- its function
may  be likened to a crossbar switch, relaying messages from
one domain into another.  In the process, it can do  a  lim-
ited  amount  of  message  header editing to put the message
into a format that is appropriate for the receiving  domain.
All  of  this  is  done under the control of a configuration
file.

     Due to the requirements of  flexibility  for  sendmail,
the  configuration  file  can  seem somewhat unapproachable.
However, there are only a few basic configurations for  most
sites, for which standard configuration files have been sup-
plied.  Most other configurations can be built by  adjusting
an existing configuration file incrementally.

     Sendmail  is  based  on  RFC 821 (Simple Mail Transport
Protocol), RFC 822 (Internet Mail Headers Format),  RFC  974
(MX  routing),  RFC  1123  (Internet Host Requirements), RFC
1413 (Identification server), RFC 1652 (SMTP 8BITMIME Exten-
sion),  RFC  1869  (SMTP Service Extensions), RFC 1870 (SMTP
SIZE Extension), RFC 1891 (SMTP  Delivery  Status  Notifica-
tions), RFC 1892 (Multipart/Report), RFC 1893 (Enhanced Mail
System Status Codes), RFC 1894  (Delivery  Status  Notifica-
tions),  RFC 1985 (SMTP Service Extension for Remote Message
Queue  Starting),  RFC  2033  (Local  Message   Transmission
____________________
   DISCLAIMER: This documentation is under modification.
   Sendmail is a trademark of Sendmail, Inc.  US Patent Num-
bers 6865671, 6986037.




Sendmail Installation and Operation Guide           SMM:08-1







SMM:08-2           Sendmail Installation and Operation Guide


Protocol),  RFC  2034  (SMTP Service Extension for Returning
Enhanced Error Codes), RFC 2045 (MIME),  RFC  2476  (Message
Submission),  RFC  2487  (SMTP  Service Extension for Secure
SMTP over TLS), RFC 2554 (SMTP Service Extension for Authen-
tication),  RFC  2821  (Simple  Mail Transfer Protocol), RFC
2822 (Internet Message Format), RFC 2852  (Deliver  By  SMTP
Service Extension), and RFC 2920 (SMTP Service Extension for
Command Pipelining).  However, since sendmail is designed to
work in a wider world, in many cases it can be configured to
exceed these protocols.  These cases are described herein.

     Although sendmail is intended to run without  the  need
for monitoring, it has a number of features that may be used
to monitor or adjust the  operation  under  unusual  circum-
stances.  These features are described.

     Section  one  describes  how  to  do  a  basic sendmail
installation.  Section two explains the day-to-day  informa-
tion  you  should know to maintain your mail system.  If you
have a relatively normal site,  these  two  sections  should
contain  sufficient  information for you to install sendmail
and keep it happy.  Section three has information  regarding
the  command  line  arguments.   Section four describes some
parameters that may be safely tweaked.   Section  five  con-
tains  the  nitty-gritty information about the configuration
file.  This section is for masochists and  people  who  must
write  their  own configuration file.  Section six describes
configuration  that  can  be  done  at  compile  time.   The
appendixes give a brief but detailed explanation of a number
of features not described in the rest of the paper.

































Sendmail Installation and Operation Guide           SMM:08-7


1.  BASIC INSTALLATION

        There are two basic steps  to  installing  sendmail.
   First,  you  have  to compile and install the binary.  If
   sendmail has already been ported to your operating system
   that should be simple.  Second, you must build a run-time
   configuration file.  This is a file that  sendmail  reads
   when  it  starts  up  that describes the mailers it knows
   about, how to parse addresses, how to rewrite the message
   header,  and  the  settings of various options.  Although
   the configuration file can be quite complex, a configura-
   tion can usually be built using an M4-based configuration
   language.  Assuming you have the standard  sendmail  dis-
   tribution, see cf/README for further information.

        The  remainder  of  this  section  will describe the
   installation of sendmail assuming you can use one of  the
   existing  configurations  and that the standard installa-
   tion parameters are acceptable.  All pathnames and  exam-
   ples  are  given  from  the root of the sendmail subtree,
   normally /usr/src/usr.sbin/sendmail on 4.4BSD-based  sys-
   tems.

        Continue  with  the next section if you need/want to
   compile sendmail yourself.  If you have a running  binary
   already  on your system, you should probably skip to sec-
   tion 1.2.

   1.1.  Compiling Sendmail

           All sendmail source is in the sendmail  subdirec-
      tory.   To  compile  sendmail,  "cd" into the sendmail
      directory and type

          ./Build

      This will leave the binary in an  appropriately  named
      subdirectory, e.g., obj.BSD-OS.2.1.i386.  It works for
      multiple object versions  compiled  out  of  the  same
      directory.

      1.1.1.  Tweaking the Build Invocation

              You  can give parameters on the Build command.
         In most cases these are only used  when  the  obj.*
         directory   is  first  created.   To  restart  from
         scratch, use -c.  These commands include:

         -L libdirs
              A list of directories to search for libraries.

         -I incdirs
              A list of directories to  search  for  include










SMM:08-8           Sendmail Installation and Operation Guide


              files.

         -E envar=value
              Set  an  environment  variable to an indicated
              value before compiling.

         -c   Create a new obj.*  tree before running.

         -f siteconfig
              Read the indicated  site  configuration  file.
              If  this  parameter  is  not  specified, Build
              includes   all   of    the    files    $BUILD-
              TOOLS/Site/site.$oscf.m4      and      $BUILD-
              TOOLS/Site/site.config.m4,  where  $BUILDTOOLS
              is  normally ../devtools and $oscf is the same
              name as used on  the  obj.*   directory.   See
              below for a description of the site configura-
              tion file.

         -S   Skip  auto-configuration.   Build  will  avoid
              auto-detecting  libraries if this is set.  All
              libraries and map definitions must  be  speci-
              fied in the site configuration file.

         Most  other  parameters are passed to the make pro-
         gram; for details see $BUILDTOOLS/README.

      1.1.2.  Creating a Site Configuration File

              (This section is not yet complete.   For  now,
         see  the  file  devtools/README  for details.)  See
         sendmail/README for various compilation flags  that
         can be set.

      1.1.3.  Tweaking the Makefile

              Sendmail  supports  two  different formats for
         the local (on disk) version of  databases,  notably
         the aliases database.  At least one of these should
         be defined if at all possible.

         NDBM      The  ``new  DBM''  format,  available  on
                   nearly  all  systems  around today.  This
                   was the preferred format prior to 4.4BSD.
                   It allows such complex things as multiple
                   databases and closing  a  currently  open
                   database.

         NEWDB     The  Berkeley  DB  package.   If you have
                   this, use it.  It  allows  long  records,
                   multiple  open  databases, real in-memory
                   caching, and so forth.   You  can  define
                   this in conjunction with NDBM; if you do,










Sendmail Installation and Operation Guide           SMM:08-9


                   old alias databases are read, but when  a
                   new  database  is  created  it will be in
                   NEWDB format.  As a nasty  hack,  if  you
                   have NEWDB, NDBM, and NIS defined, and if
                   the alias file  name  includes  the  sub-
                   string  "/yp/", sendmail will create both
                   new and old versions of  the  alias  file
                   during   a  newalias  command.   This  is
                   required because the  Sun  NIS/YP  system
                   reads  the DBM version of the alias file.
                   It's ugly as sin, but it works.

         If neither of these are defined, sendmail reads the
         alias  file  into memory on every invocation.  This
         can be slow and should be avoided.  There are  also
         several methods for remote database access:

         LDAP      Lightweight Directory Access Protocol.

         NIS       Sun's  Network Information Services (for-
                   merly YP).

         NISPLUS   Sun's NIS+ services.

         NETINFO   NeXT's NetInfo service.

         HESIOD    Hesiod service (from Athena).

         Other compilation  flags  are  set  in  conf.h  and
         should be predefined for you unless you are porting
         to a new environment.  For more options  see  send-
         mail/README.

      1.1.4.  Compilation and installation

              After  making  the  local system configuration
         described above, You should be able to compile  and
         install the system.  The script "Build" is the best
         approach on most systems:

             ./Build

         This will use uname(1) to create a custom  Makefile
         for your environment.

              If  you are installing in the standard places,
         you should be able to install using

             ./Build install

         This should install the  binary  in  /usr/sbin  and
         create    links    from   /usr/bin/newaliases   and
         /usr/bin/mailq  to  /usr/sbin/sendmail.   On   most










SMM:08-10          Sendmail Installation and Operation Guide


         systems  it will also format and install man pages.
         Notice: as of version 8.12 sendmail will no  longer
         be  installed  set-user-ID root by default.  If you
         really want to use the old method, you can  specify
         it as target:

             ./Build install-set-user-id


   1.2.  Configuration Files

           Sendmail  cannot  operate without a configuration
      file.  The configuration  defines  the  mail  delivery
      mechanisms  understood  at  this  site,  how to access
      them, how to forward email to remote mail systems, and
      a  number  of  tuning  parameters.  This configuration
      file is detailed in the later portion  of  this  docu-
      ment.

           The  sendmail  configuration  can  be daunting at
      first.  The world is complex, and the mail  configura-
      tion  reflects  that.   The  distribution  includes an
      m4-based configuration package that hides a lot of the
      complexity.  See cf/README for details.

           Our  configuration  files  are processed by m4 to
      facilitate local customization; the  directory  cf  of
      the   sendmail  distribution  directory  contains  the
      source files.  This directory contains several  subdi-
      rectories:

      cf        Both   site-dependent  and  site-independent
                descriptions of hosts.  These can be literal
                host  names  (e.g.,  "ucbvax.mc")  when  the
                hosts are gateways or more general  descrip-
                tions  (such  as  "generic-solaris2.mc" as a
                general  description  of  an  SMTP-connected
                host  running Solaris 2.x.  Files ending .mc
                (``M4   Configuration'')   are   the   input
                descriptions;  the  output  is in the corre-
                sponding .cf file.  The general structure of
                these files is described below.

      domain    Site-dependent    subdomain    descriptions.
                These are tied to the way your  organization
                wants   to   do  addressing.   For  example,
                domain/CS.Berkeley.EDU.m4 is our description
                for  hosts in the CS.Berkeley.EDU subdomain.
                These are referenced  using  the  DOMAIN  m4
                macro in the .mc file.

      feature   Definitions  of  specific features that some
                particular host in  your  site  might  want.










Sendmail Installation and Operation Guide          SMM:08-11


                These  are  referenced  using the FEATURE m4
                macro.  An example  feature  is  use_cw_file
                (which    tells    sendmail   to   read   an
                /etc/mail/local-host-names file  on  startup
                to find the set of local names).

      hack      Local  hacks,  referenced  using the HACK m4
                macro.  Try to avoid these.   The  point  of
                having  them  here  is to make it clear that
                they smell.

      m4        Site-independent m4(1)  include  files  that
                have information common to all configuration
                files.   This  can  be  thought  of   as   a
                "#include" directory.

      mailer    Definitions of mailers, referenced using the
                MAILER m4 macro.  The mailer types that  are
                known  in  this distribution are fax, local,
                smtp, uucp, and  usenet.   For  example,  to
                include  support for the UUCP-based mailers,
                use "MAILER(uucp)".

      ostype    Definitions  describing  various   operating
                system environments (such as the location of
                support files).  These are referenced  using
                the OSTYPE m4 macro.

      sh        Shell  files  used  by the m4 build process.
                You shouldn't have to mess with these.

      siteconfig
                Local UUCP connectivity  information.   This
                directory  has  been supplanted by the mail-
                ertable  feature;  any  new   configurations
                should  use  that  feature  to  do UUCP (and
                other) routing.  The use of  this  directory
                is deprecated.

           If you are in a new domain (e.g., a company), you
      will probably want to create a cf/domain file for your
      domain.   This consists primarily of relay definitions
      and features you want enabled site-wide: for  example,
      Berkeley's domain definition defines relays for BitNET
      and UUCP.  These are specific to Berkeley, and  should
      be   fully-qualified   internet-style   domain  names.
      Please check to make certain they are  reasonable  for
      your domain.

           Subdomains  at  Berkeley  are also represented in
      the cf/domain  directory.   For  example,  the  domain
      CS.Berkeley.EDU  is  the  Computer  Science subdomain,
      EECS.Berkeley.EDU is the  Electrical  Engineering  and










SMM:08-12          Sendmail Installation and Operation Guide


      Computer  Sciences  subdomain, and S2K.Berkeley.EDU is
      the Sequoia 2000 subdomain.  You will probably have to
      add  an  entry to this directory to be appropriate for
      your domain.

           You will have to use or create .mc files  in  the
      cf/cf  subdirectory  for your hosts.  This is detailed
      in the cf/README file.

   1.3.  Details of Installation Files

           This subsection describes the files that comprise
      the sendmail installation.

      1.3.1.  /usr/sbin/sendmail

              The   binary   for   sendmail  is  located  in
         /usr/sbin[1].  It should be set-group-ID  smmsp  as
         described  in sendmail/SECURITY.  For security rea-
         sons, /, /usr, and /usr/sbin  should  be  owned  by
         root, mode 0755[2].

      1.3.2.  /etc/mail/sendmail.cf

              This  is the main configuration file for send-
         mail[3].  This is one of the two  non-library  file
         names  compiled  into  sendmail[4],  the  other  is
         /etc/mail/submit.cf.

              The configuration  file  is  normally  created
         using  the  distribution files described above.  If
         you   have   a    particularly    unusual    system
____________________
   [1]This is usually /usr/sbin on 4.4BSD and newer systems;
many  systems install it in /usr/lib.  I understand it is in
/usr/ucblib on System V Release 4.
   [2]Some  vendors  ship  them owned by bin; this creates a
security hole that is  not  actually  related  to  sendmail.
Other  important  directories  that  should have restrictive
ownerships  and  permissions  are  /bin,   /usr/bin,   /etc,
/etc/mail, /usr/etc, /lib, and /usr/lib.
   [3]Actually, the pathname varies depending on the operat-
ing system; /etc/mail is the preferred directory.  Some old-
er systems install it in /usr/lib/sendmail.cf, and I've also
seen  it in /usr/ucblib.  If you want to move this file, add
-D_PATH_SENDMAILCF=\"/file/name\" to the flags passed to the
C compiler.  Moving this file is not recommended: other pro-
grams and scripts know of this location.
   [4]The system libraries can  reference  other  files;  in
particular,  system  library subroutines that sendmail calls
probably reference /etc/passwd and /etc/resolv.conf.












Sendmail Installation and Operation Guide          SMM:08-13


         configuration you may need to create a special ver-
         sion.  The format of this file is detailed in later
         sections of this document.

      1.3.3.  /etc/mail/submit.cf

              This  is  the  configuration file for sendmail
         when it is used for  initial  mail  submission,  in
         which case it is also called ``Mail Submission Pro-
         gram'' (MSP) in contrast to ``Mail Transfer Agent''
         (MTA).   Starting  with version 8.12, sendmail uses
         one of two different configuration files  based  on
         its  operation  mode  (or  the new -A option).  For
         initial  mail  submission,  i.e.,  if  one  of  the
         options  -bm  (default),  -bs,  or -t is specified,
         submit.cf is used (if available), for other  opera-
         tions sendmail.cf is used.  Details can be found in
         sendmail/SECURITY.  submit.cf is shipped with send-
         mail  (in  cf/cf/) and is installed by default.  If
         changes to the configuration need to be made, start
         with  cf/cf/submit.mc and follow the instruction in
         cf/README.

      1.3.4.  /usr/bin/newaliases

              The newaliases command should just be  a  link
         to sendmail:

             rm -f /usr/bin/newaliases
             ln -s /usr/sbin/sendmail /usr/bin/newaliases

         This  can  be installed in whatever search path you
         prefer for your system.

      1.3.5.  /usr/bin/hoststat

              The hoststat command should just be a link  to
         sendmail, in a fashion similar to newaliases.  This
         command lists the status of the last mail  transac-
         tion  with all remote hosts.  The -v flag will pre-
         vent the status display from being  truncated.   It
         functions  only when the HostStatusDirectory option
         is set.

      1.3.6.  /usr/bin/purgestat

              This command is also a link to  sendmail.   It
         flushes  expired  (Timeout.hoststatus)  information
         that is stored in the HostStatusDirectory tree.














SMM:08-14          Sendmail Installation and Operation Guide


      1.3.7.  /var/spool/mqueue

              The directory /var/spool/mqueue should be cre-
         ated to hold the mail queue.  This directory should
         be mode 0700 and owned by root.

              The actual path of this directory  is  defined
         by  the  QueueDirectory  option  of the sendmail.cf
         file.  To use multiple queues, supply a value  end-
         ing     with    an    asterisk.     For    example,
         /var/spool/mqueue/qd* will use all of the  directo-
         ries  or  symbolic  links  to directories beginning
         with `qd' in /var/spool/mqueue  as  queue  directo-
         ries.   Do not change the queue directory structure
         while sendmail is running.

              If these directories  have  subdirectories  or
         symbolic links to directories named `qf', `df', and
         `xf', then these will be  used  for  the  different
         queue  file  types.   That  is,  the data files are
         stored in the  `df'  subdirectory,  the  transcript
         files  are stored in the `xf' subdirectory, and all
         others are stored in the `qf' subdirectory.

              If shared memory support is compiled in, send-
         mail  stores  the  available  diskspace in a shared
         memory segment to make the values readily available
         to  all children without incurring system overhead.
         In this case, only the  daemon  updates  the  data;
         i.e., the sendmail daemon creates the shared memory
         segment and deletes it if it is terminated.  To use
         this, sendmail must have been compiled with support
         for shared memory (-DSM_CONF_SHM)  and  the  option
         SharedMemoryKey  must  be  set.  Notice: do not use
         the same key for sendmail invocations with  differ-
         ent queue directories or different queue group dec-
         larations.  Access to shared  memory  is  not  con-
         trolled  by  locks, i.e., there is a race condition
         when data in the shared memory  is  updated.   How-
         ever,  since operation of sendmail does not rely on
         the data in the shared memory, this does not  nega-
         tively influence the behavior.

      1.3.8.  /var/spool/clientmqueue

              The  directory  /var/spool/clientmqueue should
         be created to hold the mail queue.  This  directory
         should  be mode 0770 and owned by user smmsp, group
         smmsp.

              The actual path of this directory  is  defined
         by the QueueDirectory option of the submit.cf file.











Sendmail Installation and Operation Guide          SMM:08-15


      1.3.9.  /var/spool/mqueue/.hoststat

              This  is a typical value for the HostStatusDi-
         rectory option, containing one file per  host  that
         this  sendmail  has  chatted  with recently.  It is
         normally a subdirectory of mqueue.

      1.3.10.  /etc/mail/aliases*

              The    system    aliases    are    held     in
         "/etc/mail/aliases".   A  sample is given in "send-
         mail/aliases" which  includes  some  aliases  which
         must be defined:

             cp sendmail/aliases /etc/mail/aliases
             edit /etc/mail/aliases

         You  should  extend this file with any aliases that
         are apropos to your system.

              Normally sendmail looks at a database  version
         of      the     files,     stored     either     in
         "/etc/mail/aliases.dir" and "/etc/mail/aliases.pag"
         or  "/etc/mail/aliases.db" depending on which data-
         base package you are using.   The  actual  path  of
         this file is defined in the AliasFile option of the
         sendmail.cf file.

              The permissions of  the  alias  file  and  the
         database  versions  should be 0640 to prevent local
         denial of service attacks as explained in  the  top
         level  README in the sendmail distribution.  If the
         permissions  0640  are  used,  be  sure  that  only
         trusted users belong to the group assigned to those
         files.  Otherwise, files should not even  be  group
         readable.

      1.3.11.  /etc/rc or /etc/init.d/sendmail

              It  will be necessary to start up the sendmail
         daemon when your system reboots.  This daemon  per-
         forms  two functions: it listens on the SMTP socket
         for connections (to receive mail from a remote sys-
         tem)  and  it  processes  the queue periodically to
         insure that mail gets delivered when hosts come up.

              If  necessary,  add  the  following  lines  to
         "/etc/rc"  (or  "/etc/rc.local"  as appropriate) in
         the area where it is starting up the daemons  on  a
         BSD-base  system,  or on a System-V-based system in
         one    of    the    startup    files,     typically
         "/etc/init.d/sendmail":











SMM:08-16          Sendmail Installation and Operation Guide


             if [ -f /usr/sbin/sendmail -a -f /etc/mail/sendmail.cf ]; then
                  (cd /var/spool/mqueue; rm -f xf*)
                  /usr/sbin/sendmail -bd -q30m &
                  echo -n ' sendmail' >/dev/console
             fi

         The  "cd"  and  "rm" commands insure that all tran-
         script files have been  removed;  extraneous  tran-
         script  files may be left around if the system goes
         down in the middle of processing  a  message.   The
         line  that actually invokes sendmail has two flags:
         "-bd" causes it to listen on  the  SMTP  port,  and
         "-q30m" causes it to run the queue every half hour.

              Some people use a more complex startup script,
         removing zero length qf/hf/Qf files  and  df  files
         for  which there is no qf/hf/Qf file.  Note this is
         not advisable.  For example, see Figure  1  for  an
         example  of  a complex script which does this clean
         up.

      1.3.12.  /etc/mail/helpfile

              This is the help file used by  the  SMTP  HELP
         command.   It should be copied from "sendmail/help-
         file":

             cp sendmail/helpfile /etc/mail/helpfile

         The actual path of this  file  is  defined  in  the
         HelpFile option of the sendmail.cf file.

      1.3.13.  /etc/mail/statistics

              If  you  wish to collect statistics about your
         mail  traffic,   you   should   create   the   file
         "/etc/mail/statistics":

             cp /dev/null /etc/mail/statistics
             chmod 0600 /etc/mail/statistics

         This  file  does  not grow.  It is printed with the
         program "mailstats/mailstats.c."  The  actual  path
         of  this  file  is  defined  in the S option of the
         sendmail.cf file.

      1.3.14.  /usr/bin/mailq

              If sendmail is invoked  as  "mailq,"  it  will
         simulate  the  -bp  flag (i.e., sendmail will print
         the contents of the mail queue; see  below).   This
         should be a link to /usr/sbin/sendmail.











Sendmail Installation and Operation Guide          SMM:08-17



____________________________________________________________

#!/bin/sh
# remove zero length qf/hf/Qf files
for qffile in qf* hf* Qf*
do
     if [ -r $qffile ]
     then
          if [ ! -s $qffile ]
          then
               echo -n " <zero: $qffile>" > /dev/console
               rm -f $qffile
          fi
     fi
done
# rename tf files to be qf if the qf does not exist
for tffile in tf*
do
     qffile=`echo $tffile | sed 's/t/q/'`
     if [ -r $tffile -a ! -f $qffile ]
     then
          echo -n " <recovering: $tffile>" > /dev/console
          mv $tffile $qffile
     else
          if [ -f $tffile ]
          then
               echo -n " <extra: $tffile>" > /dev/console
               rm -f $tffile
          fi
     fi
done
# remove df files with no corresponding qf/hf/Qf files
for dffile in df*
do
     qffile=`echo $dffile | sed 's/d/q/'`
     hffile=`echo $dffile | sed 's/d/h/'`
     Qffile=`echo $dffile | sed 's/d/Q/'`
     if [ -r $dffile -a ! -f $qffile -a ! -f $hffile -a ! -f $Qffile ]
     then
          echo -n " <incomplete: $dffile>" > /dev/console
          mv $dffile `echo $dffile | sed 's/d/D/'`
     fi
done
# announce files that have been saved during disaster recovery
for xffile in [A-Z]f*
do
     if [ -f $xffile ]
     then
          echo -n " <panic: $xffile>" > /dev/console
     fi
done











SMM:08-18          Sendmail Installation and Operation Guide


            Figure 1 -- A complex startup script
____________________________________________________________


      1.3.15.  sendmail.pid

              sendmail  stores  its  current pid in the file
         specified  by  the  PidFile  option   (default   is
         _PATH_SENDMAILPID).    sendmail  uses  TempFileMode
         (which defaults to 0600) as the permissions of that
         file  to prevent local denial of service attacks as
         explained in the top level README in  the  sendmail
         distribution.   If the file already exists, then it
         might  be  necessary  to  change  the   permissions
         accordingly, e.g.,

             chmod 0600 /var/run/sendmail.pid

         Note that as of version 8.13, this file is unlinked
         when sendmail exits.  As a result of this change, a
         script such as the following, which may have worked
         prior to 8.13, will no longer work:

             # stop & start sendmail
             PIDFILE=/var/run/sendmail.pid
             kill `head -1 $PIDFILE`
             `tail -1 $PIDFILE`

         because it assumes  that  the  pidfile  will  still
         exist  even  after  killing the process to which it
         refers.  Below is a script  which  will  work  cor-
         rectly on both newer and older versions:

             # stop & start sendmail
             PIDFILE=/var/run/sendmail.pid
             pid=`head -1 $PIDFILE`
             cmd=`tail -1 $PIDFILE`
             kill $pid
             $cmd

         This is just an example script, it does not perform
         any error checks, e.g., whether the pidfile  exists
         at all.

      1.3.16.  Map Files

              To  prevent local denial of service attacks as
         explained in the top level README in  the  sendmail
         distribution,  the permissions of map files created
         by makemap should be 0640.  The use of 0640 implies
         that   only  trusted  users  belong  to  the  group
         assigned to those files.  If  those  files  already
         exist,  then  it  might  be necessary to change the










Sendmail Installation and Operation Guide          SMM:08-19


         permissions accordingly, e.g.,

             cd /etc/mail
             chmod 0640 *.db *.pag *.dir


2.  NORMAL OPERATIONS

   2.1.  The System Log

           The system log is  supported  by  the  syslogd(8)
      program.   All messages from sendmail are logged under
      the LOG_MAIL facility[5].

      2.1.1.  Format

              Each  line  in  the  system  log consists of a
         timestamp, the name of the machine  that  generated
         it  (for  logging  from  several  machines over the
         local area network), the word  "sendmail:",  and  a
         message[6].   Most  messages  are  a  sequence   of
         name=value pairs.

              The  two  most  common lines are logged when a
         message is processed.  The first logs  the  receipt
         of  a  message;  there will be exactly one of these
         per message.  Some fields may be omitted if they do
         not contain interesting information.  Fields are:

         from      The envelope sender address.

         size      The size of the message in bytes.

         class     The  class  (i.e., numeric precedence) of
                   the message.

         pri       The initial message  priority  (used  for
                   queue sorting).

         nrcpts    The  number  of  envelope  recipients for
                   this message (after aliasing and forward-
                   ing).

         msgid     The  message  id of the message (from the
                   header).

____________________
   [5]Except on Ultrix, which does not support facilities in
the syslog.
   [6]This  format  may  vary  slightly  if  your vendor has
changed the syntax.












SMM:08-20          Sendmail Installation and Operation Guide


         bodytype  The message body type (7BIT or 8BITMIME),
                   as determined from the envelope.

         proto     The protocol used to receive this message
                   (e.g., ESMTP or UUCP)

         daemon    The daemon name  from  the  DaemonPortOp-
                   tions setting.

         relay     The machine from which it was received.

         There  is also one line logged per delivery attempt
         (so there can be several per message if delivery is
         deferred or there are multiple recipients).  Fields
         are:

         to        A comma-separated list of the  recipients
                   to this mailer.

         ctladdr   The  ``controlling  user'',  that is, the
                   name of the user whose credentials we use
                   for delivery.

         delay     The  total  delay  between  the time this
                   message  was  received  and  the  current
                   delivery attempt.

         xdelay    The  amount of time needed in this deliv-
                   ery attempt (normally indicative  of  the
                   speed of the connection).

         mailer    The name of the mailer used to deliver to
                   this recipient.

         relay     The  name  of  the  host  that   actually
                   accepted (or rejected) this recipient.

         dsn       The  enhanced  error  code  (RFC 2034) if
                   available.

         stat      The delivery status.

         Not all fields are present  in  all  messages;  for
         example,  the relay is usually not listed for local
         deliveries.

      2.1.2.  Levels

              If  you  have  syslogd(8)  or  an   equivalent
         installed,  you  will be able to do logging.  There
         is a  large  amount  of  information  that  can  be
         logged.   The  log  is  arranged as a succession of
         levels.  At the lowest level only extremely strange










Sendmail Installation and Operation Guide          SMM:08-21


         situations  are logged.  At the highest level, even
         the  most  mundane  and  uninteresting  events  are
         recorded  for posterity.  As a convention, log lev-
         els under ten are  considered  generally  "useful;"
         log levels above 64 are reserved for debugging pur-
         poses.  Levels from 11-64 are reserved for  verbose
         information that some sites might want.

              A  complete  description  of the log levels is
         given in section ``Log Level''.

   2.2.  Dumping State

           You can ask sendmail to log a dump  of  the  open
      files and the connection cache by sending it a SIGUSR1
      signal.  The results are logged at LOG_DEBUG priority.

   2.3.  The Mail Queues

           Mail messages may either be delivered immediately
      or  be  held  for  later  delivery.  Held messages are
      placed into a holding directory called a mail queue.

           A mail message may be queued for these reasons:

       + If a mail message is temporarily undeliverable,  it
         is  queued and delivery is attempted later.  If the
         message is addressed to multiple recipients, it  is
         queued  only  for those recipients to whom delivery
         is not immediately possible.
       + If the SuperSafe option is set to  true,  all  mail
         messages are queued while delivery is attempted.
       + If  the DeliveryMode option is set to queue-only or
         defer, all mail is queued, and no immediate  deliv-
         ery is attempted.
       + If  the  load average becomes higher than the value
         of the  QueueLA  option  and  the  QueueFactor  (q)
         option  divided  by  the  difference in the current
         load average and the QueueLA  option  plus  one  is
         less than the priority of the message, messages are
         queued rather than immediately delivered.
       + One or more addresses are marked as  expensive  and
         delivery  is  postponed until the next queue run or
         one or more address are marked as held  via  mailer
         which uses the hold mailer flag.
       + The mail message has been marked as quarantined via
         a mail filter or rulesets.
       +

      2.3.1.  Queue Groups and Queue Directories

              There are one or more mail queues.  Each  mail
         queue  belongs to a queue group.  There is always a










SMM:08-22          Sendmail Installation and Operation Guide


         default  queue  group  that  is  called  ``mqueue''
         (which  is where messages go by default unless oth-
         erwise specified).  The  directory  or  directories
         which  comprise  the default queue group are speci-
         fied by the QueueDirectory option.  There are  zero
         or  more  additional  named  queue  groups declared
         using the Q command in the configuration file.

              By default, a queued message is placed in  the
         queue  group associated with the first recipient in
         the recipient list.  A recipient address is  mapped
         to  a queue group as follows.  First, if there is a
         ruleset called ``queuegroup'', and if this  ruleset
         maps  the  address to a queue group name, then that
         queue group is chosen.  That is, the  argument  for
         the ruleset is the recipient address and the result
         should be $# followed by the name of a queue group.
         Otherwise,   if  the  mailer  associated  with  the
         address specifies a queue group,  then  that  queue
         group  is  chosen.   Otherwise,  the  default queue
         group is chosen.

              A message with  multiple  recipients  will  be
         split  if  different queue groups are chosen by the
         mapping of recipients to queue groups.

              When a message is placed in a queue group, and
         the queue group has more than one queue, a queue is
         selected randomly.

              If  a  message  with  multiple  recipients  is
         placed into a queue group with the 'r' option (max-
         imum number of recipients per  message)  set  to  a
         positive  value  N,  and  if  there are more than N
         recipients in the message, then the message will be
         split into multiple messages, each of which have at
         most N recipients.

              Notice: if multiple queue groups are used,  do
         not move queue files around, e.g., into a different
         queue directory.  This may have weird  effects  and
         can  cause  mail  not to be delivered.  Queue files
         and directories should be  treated  as  opaque  and
         should not be manipulated directly.

      2.3.2.  Queue Runs

              sendmail has two different ways to process the
         queue(s).  The first one is to start queue  runners
         after certain intervals (``normal'' queue runners),
         the second one is to keep  queue  runner  processes
         around  (``persistent''  queue  runners).   How  to
         select either of these types is  discussed  in  the










Sendmail Installation and Operation Guide          SMM:08-23


         appendix  ``COMMAND LINE FLAGS''.  Persistent queue
         runners have the advantage that  no  new  processes
         need  to be spawned at certain intervals; they just
         sleep for a specified time after  they  finished  a
         queue  run.   Another advantage of persistent queue
         runners is that only one  process  belonging  to  a
         workgroup  (a  workgroup  is a set of queue groups)
         collects the data for a queue run and then multiple
         queue  runner  may  go ahead using that data.  This
         can significantly reduce the disk I/O necessary  to
         read  the queue files compared to starting multiple
         queue runners directly.  Their disadvantage is that
         a  new  queue  run  is only started after all queue
         runners belonging to a group finished their  tasks.
         In  case one of the queue runners tries delivery to
         a slow recipient site at the end of  a  queue  run,
         the  next  queue  run may be substantially delayed.
         In general this should be smoothed out due  to  the
         distribution of those slow jobs, however, for sites
         with small  number  of  queue  entries  this  might
         introduce noticable delays.  In general, persistent
         queue runners are only useful for  sites  with  big
         queues.

      2.3.3.  Manual Intervention

              Under normal conditions the mail queue will be
         processed transparently.   However,  you  may  find
         that  manual  intervention  is sometimes necessary.
         For example, if a major host is down for  a  period
         of  time  the  queue  may become clogged.  Although
         sendmail ought to recover gracefully when the  host
         comes up, you may find performance unacceptably bad
         in the meantime.  In that case you  want  to  check
         the  content  of  the  queue  and  manipulate it as
         explained in the next two sections.

      2.3.4.  Printing the queue

              The contents of the queue(s)  can  be  printed
         using  the  mailq command (or by specifying the -bp
         flag to sendmail):

             mailq

         This will produce a listing of the queue id's,  the
         size  of  the message, the date the message entered
         the queue,  and  the  sender  and  recipients.   If
         shared  memory support is compiled in, the flag -bP
         can be used to print the number of entries  in  the
         queue(s),  provided  a  process  updates  the data.
         However, as explained earlier, the output might  be
         slightly  wrong,  since access to the shared memory










SMM:08-24          Sendmail Installation and Operation Guide


         is not locked.  For example,  ``unknown  number  of
         entries''  might  be  shown.  The internal counters
         are updated after each queue  run  to  the  correct
         value again.

      2.3.5.  Forcing the queue

              Sendmail should run the queue automatically at
         intervals.  When using multiple queues, a  separate
         process  will  by default be created to run each of
         the queues unless the queue run is initiated  by  a
         user  with  the  verbose flag.  The algorithm is to
         read and sort the queue, and  then  to  attempt  to
         process all jobs in order.  When it attempts to run
         the job, sendmail first checks to see if the job is
         locked.  If so, it ignores the job.

              There  is  no  attempt to insure that only one
         queue processor exists at any time, since there  is
         no  guarantee  that  a  job  cannot take forever to
         process (however, sendmail does include  heuristics
         to try to abort jobs that are taking absurd amounts
         of time; technically, this violates RFC 821, but is
         blessed  by  RFC  1123).   Due to the locking algo-
         rithm, it is impossible for one job to  freeze  the
         entire  queue.  However, an uncooperative recipient
         host or a program recipient that never returns  can
         accumulate many processes in your system.  Unfortu-
         nately, there is no completely general way to solve
         this.

              In  some cases, you may find that a major host
         going down for a couple of days may create  a  pro-
         hibitively  large queue.  This will result in send-
         mail spending an inordinate amount of time  sorting
         the  queue.   This situation can be fixed by moving
         the queue to a temporary place and creating  a  new
         queue.   The  old  queue  can be run later when the
         offending host returns to service.

              To do this,  it  is  acceptable  to  move  the
         entire queue directory:

             cd /var/spool
             mv mqueue omqueue; mkdir mqueue; chmod 0700 mqueue

         You  should then kill the existing daemon (since it
         will still be processing in the  old  queue  direc-
         tory) and create a new daemon.

              To run the old mail queue, issue the following
         command:











Sendmail Installation and Operation Guide          SMM:08-25


             /usr/sbin/sendmail -C /etc/mail/queue.cf -q

         The -C flag specifies  an  alternate  configuration
         file queue.cf which should refer to the moved queue
         directory

             O QueueDirectory=/var/spool/omqueue

         and the -q flag says to just run every job  in  the
         queue.  You can also specify the moved queue direc-
         tory on the command line

             /usr/sbin/sendmail -oQ/var/spool/omqueue -q

         but this requires that you do not have queue groups
         in  the  configuration  file, because those are not
         subdirectories of the  moved  directory.   See  the
         section   about  ``Queue  Group  Declaration''  for
         details; you most likely need a different  configu-
         ration  file  to  correctly deal with this problem.
         However, a proper  configuration  of  queue  groups
         should  avoid  filling up queue directories, so you
         shouldn't run into this problem.   If  you  have  a
         tendency  toward voyeurism, you can use the -v flag
         to watch what is going on.

              When the queue is  finally  emptied,  you  can
         remove the directory:

             rmdir /var/spool/omqueue


      2.3.6.  Quarantined Queue Items

              It  is possible to "quarantine" mail messages,
         otherwise known  as  envelopes.   Envelopes  (queue
         files)  are  stored but not considered for delivery
         or display unless the  "quarantine"  state  of  the
         envelope  is undone or delivery or display of quar-
         antined items is requested.   Quarantined  messages
         are  tagged by using a different name for the queue
         file, 'hf' instead of 'qf', and by adding the quar-
         antine reason to the queue file.

              Delivery  or  display of quarantined items can
         be requested using the  -qQ  flag  to  sendmail  or
         mailq.  Additionally, messages already in the queue
         can be quarantined or unquarantined using  the  new
         -Q flag to sendmail.  For example,

             sendmail -Qreason -q[!][I|R|S][matchstring]

         Quarantines  the  normal  queue  items matching the










SMM:08-26          Sendmail Installation and Operation Guide


         criteria specified by the -q[!][I|R|S][matchstring]
         using the reason given on the -Q flag.  Likewise,

             sendmail -qQ -Q[reason] -q[!][I|R|S|Q][matchstring]

         Change  the  quarantine  reason for the quarantined
         items  matching  the  criteria  specified  by   the
         -q[!][I|R|S|Q][matchstring]  using the reason given
         on the -Q flag.  If there is no reason,
          unquarantine the matching items and make them nor-
         mal  queue  items.   Note  that  the -qQ flag tells
         sendmail to operate on quarantined items instead of
         normal items.

   2.4.  Disk Based Connection Information

           Sendmail  stores  a  large  amount of information
      about each remote system it has connected to  in  mem-
      ory.  It is possible to preserve some of this informa-
      tion on disk as well, by using the HostStatusDirectory
      option, so that it may be shared between several invo-
      cations of sendmail.  This allows mail  to  be  queued
      immediately or skipped during a queue run if there has
      been a  recent  failure  in  connecting  to  a  remote
      machine.   Note:  information about a remote system is
      stored in a file whose pathname consists of the compo-
      nents  of the hostname in reverse order.  For example,
      the information  for  host.example.com  is  stored  in
      com./example./host.   For  top-level  domains like com
      this can create a large number of subdirectories which
      on  some  filesystems  can exhaust some limits.  More-
      over, the performance of  lookups  in  directory  with
      thousands  of  entries can be fairly slow depending on
      the filesystem implementation.

           Additionally  enabling  SingleThreadDelivery  has
      the  added effect of single-threading mail delivery to
      a destination.  This  can  be  quite  helpful  if  the
      remote  machine is running an SMTP server that is eas-
      ily overloaded or cannot accept  more  than  a  single
      connection  at  a time, but can cause some messages to
      be punted to a future queue run.  It also  applies  to
      all  hosts,  so  setting  this  because  you  have one
      machine on site that runs some software that is easily
      overrun  can  cause  mail  to other hosts to be slowed
      down.  If this option is set, you probably want to set
      the  MinQueueAge  option  as  well  and  run the queue
      fairly frequently; this  way  jobs  that  are  skipped
      because  another  sendmail is talking to the same host
      will be tried again quickly rather than being  delayed
      for a long time.












Sendmail Installation and Operation Guide          SMM:08-27


           The  disk  based  host information is stored in a
      subdirectory of the  mqueue  directory  called  .host-
      stat[7].   Removing this directory and its subdirecto-
      ries has an effect similar to  the  purgestat  command
      and  is  completely  safe.   However,  purgestat  only
      removes expired (Timeout.hoststatus) data.  The infor-
      mation  in  these  directories can be perused with the
      hoststat command, which will indicate the  host  name,
      the  last  access,  and the status of that access.  An
      asterisk in the left  most  column  indicates  that  a
      sendmail  process  currently  has  the host locked for
      mail delivery.

           The disk based connection information is  treated
      the  same  way  as memory based connection information
      for the purpose of timeouts.  By default,  information
      about host failures is valid for 30 minutes.  This can
      be adjusted with the Timeout.hoststatus option.

           The connection information stored on disk may  be
      expired  at  any time with the purgestat command or by
      invoking sendmail with the -bH switch.  The connection
      information may be viewed with the hoststat command or
      by invoking sendmail with the -bh switch.

   2.5.  The Service Switch

           The implementation  of  certain  system  services
      such as host and user name lookup is controlled by the
      service switch.  If the host operating system supports
      such  a  switch, and sendmail knows about it, sendmail
      will use the native version.  Ultrix, Solaris, and DEC
      OSF/1 are examples of such systems[8].

           If  the underlying operating system does not sup-
      port a service switch (e.g., SunOS  4.X,  HP-UX,  BSD)
      then sendmail will provide a stub implementation.  The
      ServiceSwitchFile option points to the name of a  file
      that  has  the service definitions.  Each line has the
      name of a service and the possible implementations  of
      that service.  For example, the file:

          hosts     dns files nis
          aliases   files nis
____________________
   [7]This is the usual value of the HostStatusDirectory op-
tion; it can, of  course,  go  anywhere  you  like  in  your
filesystem.
   [8]HP-UX  10  has  service  switch support, but since the
APIs are apparently not available in the libraries  sendmail
does not use the native service switch in this release.












SMM:08-28          Sendmail Installation and Operation Guide


      will ask sendmail to look for hosts in the Domain Name
      System first.  If  the  requested  host  name  is  not
      found,  it  tries  local  files,  and if that fails it
      tries NIS.  Similarly, when  looking  for  aliases  it
      will try the local files first followed by NIS.

           Notice: since sendmail must access MX records for
      correct operation, it will use DNS if it is configured
      in the ServiceSwitchFile file.  Hence an entry like

          hosts     files dns

      will not avoid DNS lookups even if a host can be found
      in /etc/hosts.

           Service switches are not  completely  integrated.
      For  example,  despite  the  fact  that the host entry
      listed in the above example specifies to look in  NIS,
      on  SunOS  this won't happen because the system imple-
      mentation of gethostbyname(3) doesn't understand this.

   2.6.  The Alias Database

           After recipient addresses are read from the  SMTP
      connection  or command line they are parsed by ruleset
      0, which must resolve to  a  {mailer,  host,  address}
      triple.   If  the flags selected by the mailer include
      the A (aliasable) flag, the address part of the triple
      is  looked up as the key (i.e., the left hand side) in
      the alias database.  If there is a match, the  address
      is  deleted  from  the send queue and all addresses on
      the right hand side of the alias are added in place of
      the  alias that was found.  This is a recursive opera-
      tion, so aliases found in the right hand side  of  the
      alias are similarly expanded.

           The alias database exists in two forms.  One is a
      text form, maintained in the  file  /etc/mail/aliases.
      The aliases are of the form

          name: name1, name2, ...

      Only local names may be aliased; e.g.,

          eric@prep.ai.MIT.EDU: eric@CS.Berkeley.EDU

      will   not   have   the   desired  effect  (except  on
      prep.ai.MIT.EDU, and they probably don't want  me)[9].
____________________
   [9]Actually, any mailer that has the `A' mailer flag  set
will  permit aliasing; this is normally limited to the local
mailer.











Sendmail Installation and Operation Guide          SMM:08-29


      Aliases  may be continued by starting any continuation
      lines with a space or a tab or by putting a  backslash
      directly  before  the  newline.  Blank lines and lines
      beginning with a sharp sign ("#") are comments.

           The second form is processed by  the  ndbm(3)[10]
      or  the Berkeley DB library.  This form is in the file
      /etc/mail/aliases.db    (if    using     NEWDB)     or
      /etc/mail/aliases.dir  and  /etc/mail/aliases.pag  (if
      using NDBM).  This is the form that sendmail  actually
      uses  to  resolve  aliases.  This technique is used to
      improve performance.

           The control of search order is  actually  set  by
      the service switch.  Essentially, the entry

          O AliasFile=switch:aliases

      is  always  added  as the first alias entry; also, the
      first alias file name without a class  (e.g.,  without
      "nis:"  on  the front) will be used as the name of the
      file for a ``files'' entry in the aliases switch.  For
      example, if the configuration file contains

          O AliasFile=/etc/mail/aliases

      and the service switch contains

          aliases   nis files nisplus

      then  aliases  will first be searched in the NIS data-
      base, then in  /etc/mail/aliases,  then  in  the  NIS+
      database.

           You  can  also  use  NIS-based  alias files.  For
      example, the specification:

          O AliasFile=/etc/mail/aliases
          O AliasFile=nis:mail.aliases@my.nis.domain

      will first search the /etc/mail/aliases file and  then
      the   map  named  "mail.aliases"  in  "my.nis.domain".
      Warning: if you build your own NIS-based alias  files,
      be  sure  to  provide the -l flag to makedbm(8) to map
      upper case letters in the keys to lower  case;  other-
      wise,  aliases  with upper case letters in their names
      won't match incoming addresses.


____________________
   [10]The gdbm package does not work.












SMM:08-30          Sendmail Installation and Operation Guide


           Additional flags can be  added  after  the  colon
      exactly like a K line -- for example:

          O AliasFile=nis:-N mail.aliases@my.nis.domain

      will search the appropriate NIS map and always include
      null bytes in the key.  Also:

          O AliasFile=nis:-f mail.aliases@my.nis.domain

      will prevent sendmail from downcasing the  key  before
      the alias lookup.

      2.6.1.  Rebuilding the alias database

              The hash or dbm version of the database may be
         rebuilt explicitly by executing the command

             newaliases

         This is equivalent to giving sendmail the -bi flag:

             /usr/sbin/sendmail -bi


              If you have multiple aliases databases  speci-
         fied,  the -bi flag rebuilds all the database types
         it understands (for example, it  can  rebuild  NDBM
         databases but not NIS databases).

      2.6.2.  Potential problems

              There  are a number of problems that can occur
         with the alias database.  They all  result  from  a
         sendmail process accessing the DBM version while it
         is only partially built.  This can happen under two
         circumstances:  One  process  accesses the database
         while another process  is  rebuilding  it,  or  the
         process  rebuilding the database dies (due to being
         killed or a system  crash)  before  completing  the
         rebuild.

              Sendmail   has  three  techniques  to  try  to
         relieve these problems.  First, it  ignores  inter-
         rupts  while  rebuilding  the database; this avoids
         the problem of someone aborting the process leaving
         a partially rebuilt database.  Second, it locks the
         database source file during the rebuild -- but that
         may not work over NFS or if the file is unwritable.
         Third, at the end of the rebuild it adds  an  alias
         of the form

             @: @










Sendmail Installation and Operation Guide          SMM:08-31


         (which  is  not  normally  legal).  Before sendmail
         will access the database, it checks to insure  that
         this entry exists[11].

      2.6.3.  List owners

              If  an  error  occurs  on sending to a certain
         address, say "x", sendmail will look for  an  alias
         of  the form "owner-x" to receive the errors.  This
         is typically useful for a mailing  list  where  the
         submitter of the list has no control over the main-
         tenance of the list itself; in this case  the  list
         maintainer  would  be  the  owner of the list.  For
         example:

             unix-wizards: eric@ucbarpa, wnj@monet, nosuchuser,
                  sam@matisse
             owner-unix-wizards: unix-wizards-request
             unix-wizards-request: eric@ucbarpa

         would cause "eric@ucbarpa" to get  the  error  that
         will  occur  when someone sends to unix-wizards due
         to the inclusion of "nosuchuser" on the list.

              List owners also  cause  the  envelope  sender
         address  to be modified.  The contents of the owner
         alias are used if they point to a single user, oth-
         erwise  the  name of the alias itself is used.  For
         this reason, and to obey Internet conventions,  the
         "owner-"  address normally points at the "-request"
         address; this causes messages to go  out  with  the
         typical   Internet   convention  of  using  ``list-
         request'' as the return address.

   2.7.  User Information Database

           This option is deprecated, use virtusertable  and
      genericstable  instead  as explained in cf/README.  If
      you have a version of sendmail with the user  informa-
      tion  database compiled in, and you have specified one
      or more databases using the U  option,  the  databases
      will be searched for a user:maildrop entry.  If found,
      the mail will be sent to the specified address.




____________________
   [11]The AliasWait option is required in the configuration
for this action to occur.  This should  normally  be  speci-
fied.












SMM:08-32          Sendmail Installation and Operation Guide


   2.8.  Per-User Forwarding (.forward Files)

           As an alternative to the alias database, any user
      may  put a file with the name ".forward" in his or her
      home directory.  If this file exists,  sendmail  redi-
      rects  mail  for  that  user  to the list of addresses
      listed in the .forward file.  Note  that  aliases  are
      fully  expanded  before  forward files are referenced.
      For example, if the home directory for user "mckusick"
      has a .forward file with contents:

          mckusick@ernie
          kirk@calder

      then  any  mail  arriving for "mckusick" will be redi-
      rected to the specified accounts.

           Actually,  the  configuration  file   defines   a
      sequence  of  filenames to check.  By default, this is
      the user's .forward file, but can  be  defined  to  be
      more  generally  using the ForwardPath option.  If you
      change this, you will have to inform your user base of
      the  change; .forward is pretty well incorporated into
      the collective subconscious.

   2.9.  Special Header Lines

           Several header lines have special interpretations
      defined by the configuration file.  Others have inter-
      pretations built into sendmail that cannot be  changed
      without   changing  the  code.   These  built-ins  are
      described here.

      2.9.1.  Errors-To:

              If errors occur  anywhere  during  processing,
         this  header will cause error messages to go to the
         listed addresses.  This  is  intended  for  mailing
         lists.

              The  Errors-To:  header was created in the bad
         old days when UUCP didn't understand  the  distinc-
         tion  between  an envelope and a header; this was a
         hack to provide what should now be  passed  as  the
         envelope sender address.  It should go away.  It is
         only used if the UseErrorsTo option is set.

              The Errors-To: header is officially deprecated
         and will go away in a future release.














Sendmail Installation and Operation Guide          SMM:08-33


      2.9.2.  Apparently-To:

              RFC  822 requires at least one recipient field
         (To:, Cc:, or Bcc: line) in every  message.   If  a
         message  comes  in with no recipients listed in the
         message then sendmail will adjust the header  based
         on the "NoRecipientAction" option.  One of the pos-
         sible actions is to add an "Apparently-To:"  header
         line for any recipients it is aware of.

              The  Apparently-To: header is non-standard and
         is both deprecated and strongly discouraged.

      2.9.3.  Precedence

              The Precedence: header can be used as a  crude
         control  of  message  priority.  It tweaks the sort
         order in the queue and can be configured to  change
         the  message  timeout  values.  The precedence of a
         message also controls how delivery status notifica-
         tions (DSNs) are processed for that message.

   2.10.  IDENT Protocol Support

           Sendmail  supports  the IDENT protocol as defined
      in RFC 1413.  Note that the RFC states a client should
      wait  at least 30 seconds for a response.  The default
      Timeout.ident is 5 seconds as many sites have  adopted
      the practice of dropping IDENT queries.  This has lead
      to delays processing  mail.   Although  this  enhances
      identification  of  the  author of an email message by
      doing a ``call back'' to  the  originating  system  to
      include  the  owner  of a particular TCP connection in
      the audit trail it is in no sense  perfect;  a  deter-
      mined forger can easily spoof the IDENT protocol.  The
      following description is excerpted from RFC 1413:

           6.  Security Considerations

           The information returned by this protocol  is  at
           most  as  trustworthy as the host providing it OR
           the organization operating the host.   For  exam-
           ple,  a PC in an open lab has few if any controls
           on it to prevent a user from having this protocol
           return  any identifier the user wants.  Likewise,
           if the host has been compromised the  information
           returned may be completely erroneous and mislead-
           ing.

           The Identification Protocol is not intended as an
           authorization  or  access  control  protocol.  At
           best, it provides some additional auditing infor-
           mation  with  respect  to  TCP  connections.   At










SMM:08-34          Sendmail Installation and Operation Guide


           worst, it can provide misleading,  incorrect,  or
           maliciously incorrect information.

           The  use of the information returned by this pro-
           tocol for other than auditing  is  strongly  dis-
           couraged.    Specifically,  using  Identification
           Protocol information to make access control deci-
           sions  -  either  as the primary method (i.e., no
           other checks) or as an adjunct to  other  methods
           may  result  in  a weakening of normal host secu-
           rity.

           An Identification server may  reveal  information
           about users, entities, objects or processes which
           might normally be considered private.  An Identi-
           fication server provides service which is a rough
           analog of the CallerID services provided by  some
           phone companies and many of the same privacy con-
           siderations and arguments that apply to the  Cal-
           lerID  service  apply  to Identification.  If you
           wouldn't run a "finger"  server  due  to  privacy
           considerations  you may not want to run this pro-
           tocol.

      In some cases your system may not work  properly  with
      IDENT  support  due to a bug in the TCP/IP implementa-
      tion.  The symptoms will be that for  some  hosts  the
      SMTP connection will be closed almost immediately.  If
      this is true or if you do not want to use  IDENT,  you
      should  set  the IDENT timeout to zero; this will dis-
      able the IDENT protocol.

3.  ARGUMENTS

        The  complete  list  of  arguments  to  sendmail  is
   described  in detail in Appendix A.  Some important argu-
   ments are described here.

   3.1.  Queue Interval

           The amount of time between forking a  process  to
      run  through  the queue is defined by the -q flag.  If
      you run with delivery mode set to i or b this  can  be
      relatively  large, since it will only be relevant when
      a host that was down comes back up.  If you run  in  q
      mode  it  should be relatively short, since it defines
      the maximum amount of time that a message may  sit  in
      the queue.  (See also the MinQueueAge option.)

           RFC  1123  section  5.3.1.1  says that this value
      should be at least 30 minutes (although that  probably
      doesn't make sense if you use ``queue-only'' mode).











Sendmail Installation and Operation Guide          SMM:08-35


           Notice:  the meaning of the interval time depends
      on whether normal queue runners  or  persistent  queue
      runners  are  used.   For  the  former, it is the time
      between subsequent starts of a  queue  run.   For  the
      latter,  it is the time sendmail waits after a persis-
      tent queue runner has finished its work to  start  the
      next  one.   Hence  for  persistent queue runners this
      interval should be very low, typically  no  more  than
      two minutes.

   3.2.  Daemon Mode

           If  you  allow  incoming mail over an IPC connec-
      tion, you should have a daemon running.   This  should
      be  set  by your /etc/rc file using the -bd flag.  The
      -bd flag and the -q flag may be combined in one call:

          /usr/sbin/sendmail -bd -q30m


           An alternative approach  is  to  invoke  sendmail
      from  inetd(8)  (use the -bs -Am flags to ask sendmail
      to speak SMTP on its standard input and output and  to
      run  as MTA).  This works and allows you to wrap send-
      mail in a TCP wrapper program, but may be a bit slower
      since  the  configuration  file  has  to be re-read on
      every message that comes in.   If  you  do  this,  you
      still  need  to  have  a sendmail running to flush the
      queue:

          /usr/sbin/sendmail -q30m


   3.3.  Forcing the Queue

           In some cases you may find  that  the  queue  has
      gotten clogged for some reason.  You can force a queue
      run using the -q flag (with no value).  It  is  enter-
      taining to use the -v flag (verbose) when this is done
      to watch what happens:

          /usr/sbin/sendmail -q -v


           You can also limit the jobs to those with a  par-
      ticular  queue  identifier, recipient, sender, quaran-
      tine reason, or queue group using  one  of  the  queue
      modifiers.   For  example, "-qRberkeley" restricts the
      queue run to jobs  that  have  the  string  "berkeley"
      somewhere  in  one  of the recipient addresses.  Simi-
      larly,  "-qSstring"  limits  the  run  to   particular
      senders,  "-qIstring"  limits  it  to particular queue
      identifiers, and "-qQstring" limits it  to  particular










SMM:08-36          Sendmail Installation and Operation Guide


      quarantined  reasons  and only operated on quarantined
      queue items, and "-qGstring" limits it to a particular
      queue  group.   The named queue group will be run even
      if it is set to have 0 runners.  You may also place an
      !   before  the I or R or S or Q to indicate that jobs
      are limited to not including a particular queue  iden-
      tifier,  recipient or sender.  For example, "-q!Rseat-
      tle" limits the queue run to jobs that do not have the
      string  "seattle"  somewhere  in  one of the recipient
      addresses.  Should you need  to  terminate  the  queue
      jobs  currently active then a SIGTERM to the parent of
      the process (or processes) will cleanly stop the jobs.

   3.4.  Debugging

           There are a fairly large number  of  debug  flags
      built  into  sendmail.  Each debug flag has a category
      and a level.  Higher  levels  increase  the  level  of
      debugging activity; in most cases, this means to print
      out more information.  The convention is  that  levels
      greater  than  nine are "absurd," i.e., they print out
      so much information that you wouldn't normally want to
      see them except for debugging that particular piece of
      code.

           You should never run a production sendmail server
      in debug mode.  Many of the debug flags will result in
      debug output being sent over the SMTP  channel  unless
      the  option  -D  is used.  This will confuse many mail
      programs.  However, for testing purposes,  it  can  be
      useful  when  sending  mail manually via telnet to the
      port you are using while debugging.

           A debug category is either an integer,  like  42,
      or  a  name,  like  ANSI.   You can specify a range of
      numeric debug categories using the syntax 17-42.   You
      can  specify  a  set of named debug categories using a
      glob pattern like "sm_trace_*".  At present, only  "*"
      and "?"  are supported in these glob patterns.

           Debug flags are set using the -d option; the syn-
      tax is:

          debug-flag:        -d debug-list
          debug-list:        debug-option [ , debug-option ]*
          debug-option:      debug-categories [ . debug-level ]
          debug-categories:  integer | integer - integer | category-pattern
          category-pattern:  [a-zA-Z_*?][a-zA-Z0-9_*?]*
          debug-level:       integer

      where spaces are for reading ease only.  For example,












Sendmail Installation and Operation Guide          SMM:08-37


          -d12               Set category 12 to level 1
          -d12.3             Set category 12 to level 3
          -d3-17             Set categories 3 through 17 to level 1
          -d3-17.4           Set categories 3 through 17 to level 4
          -dANSI             Set category ANSI to level 1
          -dsm_trace_*.3     Set all named categories matching sm_trace_* to level 3

      For a complete list of the available debug  flags  you
      will  have to look at the code and the TRACEFLAGS file
      in the sendmail distribution (they are too dynamic  to
      keep  this  document up to date).  For a list of named
      debug categories in the sendmail binary, use

          ident /usr/sbin/sendmail | grep Debug


   3.5.  Changing the Values of Options

           Options can be overridden using the -o or -O com-
      mand line flags.  For example,

          /usr/sbin/sendmail -oT2m

      sets  the  T  (timeout) option to two minutes for this
      run only; the equivalent line using  the  long  option
      name is

          /usr/sbin/sendmail -OTimeout.queuereturn=2m


           Some  options  have security implications.  Send-
      mail allows you to set  these,  but  relinquishes  its
      set-user-ID   or   set-group-ID   permissions   there-
      after[12].

   3.6.  Trying a Different Configuration File

           An  alternative  configuration file can be speci-
      fied using the -C flag; for example,

          /usr/sbin/sendmail -Ctest.cf -oQ/tmp/mqueue

      uses the configuration file  test.cf  instead  of  the
      default  /etc/mail/sendmail.cf.  If the -C flag has no
      value it defaults to sendmail.cf in the current direc-
      tory.
____________________
   [12]That is, it sets its effective uid to the  real  uid;
thus,  if  you are executing as root, as from root's crontab
file or during system  startup  the  root  permissions  will
still be honored.












SMM:08-38          Sendmail Installation and Operation Guide


           Sendmail  gives  up  set-user-ID root permissions
      (if it has been installed set-user-ID root)  when  you
      use  this  flag,  so  it  is  common to use a publicly
      writable directory (such as /tmp) as the queue  direc-
      tory (QueueDirectory or Q option) while testing.

   3.7.  Logging Traffic

           Many  SMTP implementations do not fully implement
      the protocol.  For  example,  some  personal  computer
      based  SMTPs  do  not understand continuation lines in
      reply codes.  These can be very hard to trace.  If you
      suspect  such  a  problem, you can set traffic logging
      using the -X flag.  For example,

          /usr/sbin/sendmail -X /tmp/traffic -bd

      will log all traffic in the file /tmp/traffic.

           This logs a lot of data very quickly  and  should
      NEVER  be used during normal operations.  After start-
      ing up such a daemon, force the errant  implementation
      to  send  a message to your host.  All message traffic
      in and out of sendmail, including  the  incoming  SMTP
      traffic, will be logged in this file.

   3.8.  Testing Configuration Files

           When  you build a configuration table, you can do
      a certain amount of testing using the "test  mode"  of
      sendmail.  For example, you could invoke sendmail as:

          sendmail -bt -Ctest.cf

      which  would read the configuration file "test.cf" and
      enter test mode.  In this mode, you enter lines of the
      form:

          rwset address

      where  rwset  is the rewriting set you want to use and
      address is an address to apply the set to.  Test  mode
      shows  you  the steps it takes as it proceeds, finally
      showing you the address it ends up with.  You may  use
      a comma separated list of rwsets for sequential appli-
      cation of rules to an input.  For example:

          3,1,21,4 monet:bollard

      first applies ruleset three to the  input  "monet:bol-
      lard."   Ruleset  one is then applied to the output of
      ruleset three, followed similarly by rulesets  twenty-
      one and four.










Sendmail Installation and Operation Guide          SMM:08-39


           If  you  need  more  detail, you can also use the
      "-d21" flag to turn on more debugging.  For example,

          sendmail -bt -d21.99

      turns on an incredible amount of information; a single
      word  address  is  probably going to print out several
      pages worth of information.

           You should be warned  that  internally,  sendmail
      applies  ruleset 3 to all addresses.  In test mode you
      will have to do that  manually.   For  example,  older
      versions allowed you to use

          0 bruce@broadcast.sony.com

      This version requires that you use:

          3,0 bruce@broadcast.sony.com


           As of version 8.7, some other syntaxes are avail-
      able in test mode:

      .Dxvalue  defines macro x to have the indicated value.
                This is useful when debugging rules that use
                the $&x syntax.

      .Ccvalue  adds the indicated value to class c.

      =Sruleset dumps the contents of the indicated ruleset.

      -ddebug-spec
                is equivalent to the command-line flag.

      Version 8.9 introduced more features:

      ?         shows a help message.

      =M        display the known mailers.

      $m        print the value of macro m.

      $=c       print the contents of class c.

      /mx host  returns the MX records for `host'.

      /parse address
                parse address, returning the value of crack-
                addr, and the parsed address.

      /try mailer addr
                rewrite  address  into the form it will have










SMM:08-40          Sendmail Installation and Operation Guide


                when presented to the indicated mailer.

      /tryflags flags
                set flags used by parsing.  The flags can be
                `H'  for Header or `E' for Envelope, and `S'
                for Sender or `R' for Recipient.  These  can
                be  combined,  `HR'  sets  flags  for header
                recipients.

      /canon hostname
                try to canonify hostname.

      /map mapname key
                look up `key' in the indicated `mapname'.

      /quit     quit address test mode.

   3.9.  Persistent Host Status Information

           When HostStatusDirectory is enabled,  information
      about  the  status  of hosts is maintained on disk and
      can thus be shared between different instantiations of
      sendmail.  The status of the last connection with each
      remote host may be viewed with the command:

          sendmail -bh

      This information may be flushed with the command:

          sendmail -bH

      Flushing the information prevents  new  sendmail  pro-
      cesses  from loading it, but does not prevent existing
      processes from using the status information that  they
      already have.

4.  TUNING

        There  are  a number of configuration parameters you
   may want to change, depending on the requirements of your
   site.   Most of these are set using an option in the con-
   figuration  file.   For  example,  the  line   "O   Time-
   out.queuereturn=5d"  sets option "Timeout.queuereturn" to
   the value "5d" (five days).

        Most of these options have appropriate defaults  for
   most  sites.   However, sites having very high mail loads
   may find they need to tune them as appropriate for  their
   mail  load.   In  particular,  sites experiencing a large
   number of small messages, many of which are delivered  to
   many  recipients,  may  find that they need to adjust the
   parameters dealing with queue priorities.











Sendmail Installation and Operation Guide          SMM:08-41


        All versions of sendmail prior  to  8.7  had  single
   character  option  names.   As  of 8.7, options have long
   (multi-character names).  Although old  short  names  are
   still accepted, most new options do not have short equiv-
   alents.

        This section only describes the options you are most
   likely to want to tweak; read section 5 for more details.

   4.1.  Timeouts

           All time intervals are set using a scaled syntax.
      For example, "10m"  represents  ten  minutes,  whereas
      "2h30m" represents two and a half hours.  The full set
      of scales is:

          s   seconds
          m   minutes
          h   hours
          d   days
          w   weeks


      4.1.1.  Queue interval

              The argument to  the  -q  flag  specifies  how
         often  a  sub-daemon  will  run the queue.  This is
         typically set to between fifteen  minutes  and  one
         hour.   If  not set, or set to zero, the queue will
         not be run automatically.  RFC 1123 section 5.3.1.1
         recommends  that  this  be  at  least  30  minutes.
         Should you need to terminate the  queue  jobs  cur-
         rently  active  then a SIGTERM to the parent of the
         process (or processes) will cleanly stop the jobs.

      4.1.2.  Read timeouts

              Timeouts all have option names "Timeout.subop-
         tion".  Most of these control SMTP operations.  The
         recognized suboptions, their  default  values,  and
         the  minimum  values  allowed  by  RFC 2821 section
         4.5.3.2 (or RFC 1123 section 5.3.2) are:

         connect   The time to wait for an  SMTP  connection
                   to  open (the connect(2) system call) [0,
                   unspecified].  If zero, uses  the  kernel
                   default.   In  no  case  can  this option
                   extend the timeout longer than the kernel
                   provides, but it can shorten it.  This is
                   to get around  kernels  that  provide  an
                   absurdly long connection timeout (90 min-
                   utes in one case).











SMM:08-42          Sendmail Installation and Operation Guide


         iconnect  The same as connect,  except  it  applies
                   only to the initial attempt to connect to
                   a host for a given message  [0,  unspeci-
                   fied].   The  concept is that this should
                   be very short (a few seconds); hosts that
                   are  well  connected  and responsive will
                   thus be serviced immediately.  Hosts that
                   are  slow will not hold up other deliver-
                   ies in the initial delivery attempt.

         aconnect  [0,  unspecified]  The  overall   timeout
                   waiting  for  all connection for a single
                   delivery attempt to succeed.   If  0,  no
                   overall  limit  is  applied.  This can be
                   used to restrict the total amount of time
                   trying  to connect to a long list of host
                   that  could  accept  an  e-mail  for  the
                   recipient.   This  timeout does not apply
                   to FallbackMXhost, i.e., if the  time  is
                   exhausted,  the  FallbackMXhost  is tried
                   next.

         initial   The wait for  the  initial  220  greeting
                   message [5m, 5m].

         helo      The  wait for a reply from a HELO or EHLO
                   command  [5m,  unspecified].   This   may
                   require  a host name lookup, so five min-
                   utes is probably a reasonable minimum.

         mail*     The wait for a reply from a MAIL  command
                   [10m, 5m].

         rcpt*     The  wait for a reply from a RCPT command
                   [1h, 5m].  This should be long because it
                   could  be pointing at a list that takes a
                   long time to expand (see below).

         datainit* The wait for a reply from a DATA  command
                   [5m, 2m].

         datablock*#
                   The  wait  for reading a data block (that
                   is, the body of the message).  [1h,  3m].
                   This  should  be  long  because  it  also
                   applies to programs piping input to send-
                   mail  which  have no guarantee of prompt-
                   ness.

         datafinal*
                   The wait for a reply from the dot  termi-
                   nating a message.  [1h, 10m].  If this is
                   shorter than the time actually needed for










Sendmail Installation and Operation Guide          SMM:08-43


                   the  receiver  to  deliver  the  message,
                   duplicates will be  generated.   This  is
                   discussed in RFC 1047.

         rset      The  wait for a reply from a RSET command
                   [5m, unspecified].

         quit      The wait for a reply from a QUIT  command
                   [2m, unspecified].

         misc      The  wait  for a reply from miscellaneous
                   (but short) commands such  as  NOOP  (no-
                   operation)  and  VERB  (go  into  verbose
                   mode).  [2m, unspecified].

         command*# In server SMTP,  the  time  to  wait  for
                   another command.  [1h, 5m].

         ident#    The  timeout  waiting  for  a reply to an
                   IDENT query [5s[13], unspecified].

         lhlo      The wait for a reply to an LMTP LHLO com-
                   mand [2m, unspecified].

         auth      The timeout for a reply in an  SMTP  AUTH
                   dialogue [10m, unspecified].

         starttls  The timeout for a reply to an SMTP START-
                   TLS command and the  TLS  handshake  [1h,
                   unspecified].

         fileopen# The  timeout  for  opening  .forward  and
                   :include: files [60s, none].

         control#  The timeout for a complete control socket
                   transaction to complete [2m, none].

         hoststatus#
                   How  long status information about a host
                   (e.g., host down) will be  cached  before
                   it  is  considered  stale  [30m, unspeci-
                   fied].

         resolver.retrans#
                   The resolver's retransmission time inter-
                   val  (in  seconds)  [varies].   Sets both
                   Timeout.resolver.retrans.first and  Time-
                   out.resolver.retrans.normal.
____________________
   [13]On some systems the default is zero to turn the  pro-
tocol off entirely.












SMM:08-44          Sendmail Installation and Operation Guide


         resolver.retrans.first#
                   The resolver's retransmission time inter-
                   val (in seconds) for the first attempt to
                   deliver a message [varies].

         resolver.retrans.normal#
                   The resolver's retransmission time inter-
                   val (in seconds) for all resolver lookups
                   except   the   first   delivery   attempt
                   [varies].

         resolver.retry#
                   The  number  of  times  to  retransmit  a
                   resolver    query.    Sets   both   Time-
                   out.resolver.retry.first    and     Time-
                   out.resolver.retry.normal [varies].

         resolver.retry.first#
                   The  number  of  times  to  retransmit  a
                   resolver query for the first  attempt  to
                   deliver a message [varies].

         resolver.retry.normal#
                   The  number  of  times  to  retransmit  a
                   resolver query for all resolver lookups
                    except  the   first   delivery   attempt
                   [varies].

         For  compatibility with old configuration files, if
         no suboption is specified, all the timeouts  marked
         with  an  asterick  (*)  are  set  to the indicated
         value.  All but those marked with a pound sign  (#)
         apply to client SMTP.

              For example, the lines:

             O Timeout.command=25m
             O Timeout.datablock=3h

         sets  the server SMTP command timeout to 25 minutes
         and the input data block timeout to three hours.

      4.1.3.  Message timeouts

              After sitting in the queue for a few days,  an
         undeliverable  message  will  time out.  This is to
         insure that at least the sender  is  aware  of  the
         inability  to send a message.  The timeout is typi-
         cally set to five days.  It is sometimes considered
         convenient  to  also  send a warning message if the
         message is in the queue longer  than  a  few  hours
         (assuming  you  normally have good connectivity; if
         your messages normally took several hours  to  send










Sendmail Installation and Operation Guide          SMM:08-45


         you wouldn't want to do this because it wouldn't be
         an unusual event).  These timeouts  are  set  using
         the   Timeout.queuereturn   and   Timeout.queuewarn
         options in the configuration file (previously  both
         were set using the T option).

              If  the  message is submitted using the NOTIFY
         SMTP extension, warning messages will only be  sent
         if  NOTIFY=DELAY is specified.  The queuereturn and
         queuewarn timeouts can be further qualified with  a
         tag  based on the Precedence: field in the message;
         they must be one of "urgent" (indicating a positive
         non-zero  precedence),  "normal" (indicating a zero
         precedence), or "non-urgent"  (indicating  negative
         precedences).  For example, setting "Timeout.queue-
         warn.urgent=1h" sets the warning timeout for urgent
         messages  only  to  one  hour.   The  default if no
         precedence is indicated is to set the  timeout  for
         all  precedences.   If  the  message  has  a normal
         (default) precedence and it is  a  delivery  status
         notification   (DSN),  Timeout.queuereturn.dsn  and
         Timeout.queuewarn.dsn can be used to give an alter-
         native  warn  and  return time for DSNs.  The value
         "now" can be used  for  -O  Timeout.queuereturn  to
         return  entries  immediately  during  a  queue run,
         e.g., to bounce messages independent of their  time
         in the queue.

              Since  these options are global, and since you
         cannot know a priori how long another host  outside
         your  domain  will  be  down, a five day timeout is
         recommended.  This allows a recipient  to  fix  the
         problem  even  if  it  occurs at the beginning of a
         long weekend.  RFC 1123 section 5.3.1.1  says  that
         this parameter should be ``at least 4-5 days''.

              The Timeout.queuewarn value can be piggybacked
         on the T option by indicating a time after which  a
         warning  message  should  be sent; the two timeouts
         are separated by a slash.  For example, the line

             OT5d/4h

         causes email to fail after five days, but a warning
         message will be sent after four hours.  This should
         be large enough that the  message  will  have  been
         tried several times.

   4.2.  Forking During Queue Runs

           By  setting  the ForkEachJob (Y) option, sendmail
      will fork before each individual message while running
      the queue.  This option was used with earlier releases










SMM:08-46          Sendmail Installation and Operation Guide


      to prevent sendmail from consuming  large  amounts  of
      memory.   It  should no longer be necessary with send-
      mail 8.12.  If the  ForkEachJob  option  is  not  set,
      sendmail will keep track of hosts that are down during
      a queue run, which can  improve  performance  dramati-
      cally.

           If the ForkEachJob option is set, sendmail cannot
      use connection caching.

   4.3.  Queue Priorities

           Every message is assigned a priority when  it  is
      first instantiated, consisting of the message size (in
      bytes) offset by the message class  (which  is  deter-
      mined  from  the  Precedence:  header) times the "work
      class factor" and the number of recipients  times  the
      "work  recipient  factor."   The  priority  is used to
      order the queue.  Higher numbers for the priority mean
      that  the message will be processed later when running
      the queue.

           The message size is included so that  large  mes-
      sages  are  penalized relative to small messages.  The
      message class allows users  to  send  "high  priority"
      messages  by  including a "Precedence:" field in their
      message; the value of this field is looked up in the P
      lines  of the configuration file.  Since the number of
      recipients  affects  the  amount  of  load  a  message
      presents to the system, this is also included into the
      priority.

           The recipient and class factors can be set in the
      configuration  file  using the RecipientFactor (y) and
      ClassFactor (z) options respectively.  They default to
      30000  (for  the  recipient  factor) and 1800 (for the
      class factor).  The initial priority is:

     pri=msgsize-(classxClassFactor)+(nrcptxRecipientFactor)

      (Remember, higher values for this  parameter  actually
      mean  that  the  job will be treated with lower prior-
      ity.)

           The priority of a job can also be  adjusted  each
      time it is processed (that is, each time an attempt is
      made to deliver it) using the "work time factor,"  set
      by  the  RetryFactor (Z) option.  This is added to the
      priority, so it normally decreases the  precedence  of
      the  job,  on  the  grounds that jobs that have failed
      many times will tend to fail again in the future.  The
      RetryFactor option defaults to 90000.











Sendmail Installation and Operation Guide          SMM:08-47


   4.4.  Load Limiting

           Sendmail  can be asked to queue (but not deliver)
      mail if the system load average gets  too  high  using
      the QueueLA (x) option.  When the load average exceeds
      the value of the QueueLA option, the delivery mode  is
      set  to  q  (queue only) if the QueueFactor (q) option
      divided by the difference in the current load  average
      and  the QueueLA option plus one is less than the pri-
      ority of the message -- that is, the message is queued
      iff:

                        pri>LQueueFactor_

      The  QueueFactor  option  defaults  to 600000, so each
      point of load average is worth 600000 priority  points
      (as described above).

           For   drastic  cases,  the  RefuseLA  (X)  option
      defines a load average at which sendmail  will  refuse
      to  accept  network  connections.   Locally  generated
      mail, i.e., mail  which  is  not  submitted  via  SMTP
      (including  incoming  UUCP  mail),  is still accepted.
      Notice that the MSP submits mail to the MTA via  SMTP,
      and  hence  mail will be queued in the client queue in
      such a case.  Therefore it is  necessary  to  run  the
      client mail queue periodically.

   4.5.  Resource Limits

           Sendmail   has   several  parameters  to  control
      resource usage.  Besides those mentionted in the  pre-
      vious  section,  there are at least MaxDaemonChildren,
      ConnectionRateThrottle, MaxQueueChildren, and  MaxRun-
      nersPerQueue.   The  latter  two  limit  the number of
      sendmail processes that operate on the  queue.   These
      are  discussed  in  the section ``Queue Group Declara-
      tion''.  The former two can be used to limit the  num-
      ber of incoming connections.  Their appropriate values
      depend on the host operating system and the  hardware,
      e.g.,  amount  of memory.  In many situations it might
      be useful to set limits to prevent to  have  too  many
      sendmail  processes,  however,  these  limits  can  be
      abused to mount a denial of service attack.  For exam-
      ple, if MaxDaemonChildren=10 then an attacker needs to
      open only 10 SMTP sessions to the server,  leave  them
      idle  for  most  of  the time, and no more connections
      will be accepted.  If this  option  is  set  then  the
      timeouts used in a SMTP session should be lowered from
      their default values to their minimum values as speci-
      fied in RFC 2821 and listed in section 4.1.2.












SMM:08-48          Sendmail Installation and Operation Guide


   4.6.  Measures against Denial of Service Attacks

           Sendmail  has some built-in measures against sim-
      ple denial of service (DoS) attacks.  The SMTP  server
      by  default  slows  down  if too many bad commands are
      issued or if some  commands  are  repeated  too  often
      within  a session.  Details can be found in the source
      file sendmail/srvrsmtp.c by looking for the macro def-
      initions  of MAXBADCOMMANDS, MAXNOOPCOMMANDS, MAXHELO-
      COMMANDS, MAXVRFYCOMMANDS, and MAXETRNCOMMANDS.  If an
      SMTP command is issued more often than the correspond-
      ing MAXcmdCOMMANDS value, then the response is delayed
      exponentially,  starting with a sleep time of one sec-
      ond, up to a maximum of four minutes  (as  defined  by
      MAXTIMEOUT).   If  the option MaxDaemonChildren is set
      to a value greater than zero, then this could  make  a
      DoS attack even worse since it keeps a connection open
      longer than necessary.  Therefore a connection is ter-
      minated  with  a  421 SMTP reply code if the number of
      commands exceeds the limit by  a  factor  of  two  and
      MAXBADCOMMANDS  is  set  to  a value greater than zero
      (the default is 25).

   4.7.  Delivery Mode

           There are a number of delivery modes  that  send-
      mail  can operate in, set by the DeliveryMode (d) con-
      figuration option.  These modes  specify  how  quickly
      mail will be delivered.  Legal modes are:

          i   deliver interactively (synchronously)
          b   deliver in background (asynchronously)
          q   queue only (don't deliver)
          d   defer delivery attempts (don't deliver)

      There  are  tradeoffs.   Mode "i" gives the sender the
      quickest feedback, but may slow down some mailers  and
      is  hardly ever necessary.  Mode "b" delivers promptly
      but can cause large numbers of processes if you have a
      mailer  that  takes  a long time to deliver a message.
      Mode "q" minimizes the load on your machine, but means
      that  delivery  may  be  delayed  for  up to the queue
      interval.  Mode "d" is identical to  mode  "q"  except
      that it also prevents lookups in maps including the -D
      flag from working during the initial queue  phase;  it
      is  intended  for  ``dial  on demand'' sites where DNS
      lookups might cost real money.  Some simple error mes-
      sages  (e.g.,  host  unknown during the SMTP protocol)
      will be delayed using this  mode.   Mode  "b"  is  the
      usual default.

           If you run in mode "q" (queue only), "d" (defer),
      or "b"  (deliver  in  background)  sendmail  will  not










Sendmail Installation and Operation Guide          SMM:08-49


      expand  aliases and follow .forward files upon initial
      receipt of the mail.  This speeds up the  response  to
      RCPT  commands.   Mode  "i"  should not be used by the
      SMTP server.

   4.8.  Log Level

           The level of logging can  be  set  for  sendmail.
      The  default  using  a standard configuration table is
      level 9.  The levels are as follows:

      0    Minimal logging.

      1    Serious system failures  and  potential  security
           problems.

      2    Lost communications (network problems) and proto-
           col failures.

      3    Other  serious  failures,  malformed   addresses,
           transient   forward/include   errors,  connection
           timeouts.

      4    Minor failures, out of date alias databases, con-
           nection rejections via check_ rulesets.

      5    Message collection statistics.

      6    Creation  of  error  messages, VRFY and EXPN com-
           mands.

      7    Delivery failures (host or user unknown, etc.).

      8    Successful   deliveries   and   alias    database
           rebuilds.

      9    Messages  being  deferred  (due  to  a host being
           down, etc.).

      10   Database expansion (alias,  forward,  and  userdb
           lookups) and authentication information.

      11   NIS errors and end of job processing.

      12   Logs all SMTP connections.

      13   Log  bad user shells, files with improper permis-
           sions, and other questionable situations.

      14   Logs refused connections.

      15   Log all incoming and outgoing SMTP commands.











SMM:08-50          Sendmail Installation and Operation Guide


      20   Logs attempts to run locked queue  files.   These
           are not errors, but can be useful to note if your
           queue appears to be clogged.

      30   Lost  locks  (only  if  using  lockf  instead  of
           flock).

      Additionally,   values   above  64  are  reserved  for
      extremely verbose debugging output.   No  normal  site
      would ever set these.

   4.9.  File Modes

           The modes used for files depend on what function-
      ality you want and the level of security you  require.
      In  many  cases  sendmail does careful checking of the
      modes of files and  directories  to  avoid  accidental
      compromise;  if  you  want to make it possible to have
      group-writable support files you may need to  use  the
      DontBlameSendmail  option  to  turn  off some of these
      checks.

      4.9.1.  To suid or not to suid?

              Sendmail is no longer installed set-user-ID to
         root.   sendmail/SECURITY explains how to configure
         and install sendmail without  set-user-ID  to  root
         but set-group-ID which is the default configuration
         starting with 8.12.

              The daemon usually runs as root, unless  other
         measures are taken.  At the point where sendmail is
         about to exec(2) a mailer, it checks to see if  the
         userid  is zero (root); if so, it resets the userid
         and groupid to a default (set by the U=  equate  in
         the  mailer  line; if that is not set, the Default-
         User option is used).  This can  be  overridden  by
         setting  the  S flag to the mailer for mailers that
         are trusted and must be called as  root.   However,
         this  will  cause  mail  processing to be accounted
         (using sa(8)) to root rather than to the user send-
         ing the mail.

              A  middle  ground  is  to  set  the  RunAsUser
         option.  This causes sendmail to become  the  indi-
         cated  user as soon as it has done the startup that
         requires root privileges  (primarily,  opening  the
         SMTP  socket).   If  you  use  RunAsUser, the queue
         directory (normally  /var/spool/mqueue)  should  be
         owned  by  that  user,  and all files and databases
         (including  user  .forward  files,   alias   files,
         :include:  files,  and  external databases) must be
         readable by that user.  Also, since  sendmail  will










Sendmail Installation and Operation Guide          SMM:08-51


         not be able to change its uid, delivery to programs
         or files will be marked as unsafe, e.g., undeliver-
         able,  in  .forward,  aliases, and :include: files.
         Administrators can override  this  by  setting  the
         DontBlameSendmail  option  to  the setting NonRoot-
         SafeAddr.  RunAsUser is probably  best  suited  for
         firewall  configurations  that  don't  have regular
         user logins.  If the option is  used  on  a  system
         which  performs  local  delivery,  then  the  local
         delivery agent must  have  the  proper  permissions
         (i.e.,  usually  set-user-ID root) since it will be
         invoked by the RunAsUser, not by root.

      4.9.2.  Turning off security checks

              Sendmail is very particular about the modes of
         files  that  it  reads  or writes.  For example, by
         default it will refuse to read most files that  are
         group  writable on the grounds that they might have
         been tampered with by someone other than the owner;
         it will even refuse to read files in group writable
         directories.  Also, sendmail will refuse to  create
         a new aliases database in an unsafe directory.  You
         can get around this by manually creating the  data-
         base  file as a trusted user ahead of time and then
         rebuilding the aliases database with newaliases.

              If you are quite sure that your  configuration
         is  safe and you want sendmail to avoid these secu-
         rity checks, you can turn off certain checks  using
         the  DontBlameSendmail  option.   This option takes
         one or more names  that  disable  checks.   In  the
         descriptions  that follow, "unsafe directory" means
         a directory that is writable by anyone  other  than
         the owner.  The values are:

         Safe No special handling.

         AssumeSafeChown
              Assume   that   the   chown   system  call  is
              restricted to root.  Since  some  versions  of
              UNIX  permit  regular users to give away their
              files to  other  users  on  some  filesystems,
              sendmail often cannot assume that a given file
              was created by the owner, particularly when it
              is  in a writable directory.  You can set this
              flag  if  you  know  that  file  giveaway   is
              restricted on your system.

         ClassFileInUnsafeDirPath
              When  reading class files (using the F line in
              the configuration file), allow files that  are
              in unsafe directories.










SMM:08-52          Sendmail Installation and Operation Guide


         DontWarnForwardFileInUnsafeDirPath
              Prevent logging of unsafe directory path warn-
              ings for non-existent forward files.

         ErrorHeaderInUnsafeDirPath
              Allow the file named in the ErrorHeader option
              to be in an unsafe directory.

         FileDeliveryToHardLink
              Allow delivery to files that are hard links.

         FileDeliveryToSymLink
              Allow  delivery  to  files  that  are symbolic
              links.

         ForwardFileInGroupWritableDirPath
              Allow .forward files in group writable  direc-
              tories.

         ForwardFileInUnsafeDirPath
              Allow .forward files in unsafe directories.

         ForwardFileInUnsafeDirPathSafe
              Allow  a  .forward  file  that is in an unsafe
              directory to include references to program and
              files.

         GroupReadableKeyFile
              Accept a group-readable key file for STARTTLS.

         GroupReadableSASLDBFile
              Accept  a  group-readable  Cyrus SASL password
              file.

         GroupWritableAliasFile
              Allow group-writable alias files.

         GroupWritableDirPathSafe
              Change the definition of "unsafe directory" to
              consider   group-writable  directories  to  be
              safe.  World-writable directories  are  always
              unsafe.

         GroupWritableForwardFile
              Allow group writable .forward files.

         GroupWritableForwardFileSafe
              Accept  group-writable  .forward files as safe
              for program and file delivery.

         GroupWritableIncludeFile
              Allow group wriable :include: files.











Sendmail Installation and Operation Guide          SMM:08-53


         GroupWritableIncludeFileSafe
              Accept group-writable :include: files as  safe
              for program and file delivery.

         GroupWritableSASLDBFile
              Accept  a  group-writable  Cyrus SASL password
              file.

         HelpFileInUnsafeDirPath
              Allow the file named in the HelpFile option to
              be in an unsafe directory.

         IncludeFileInGroupWritableDirPath
              Allow :include: files in group writable direc-
              tories.

         IncludeFileInUnsafeDirPath
              Allow :include: files in unsafe directories.

         IncludeFileInUnsafeDirPathSafe
              Allow a :include: file that is  in  an  unsafe
              directory to include references to program and
              files.

         InsufficientEntropy
              Try to use  STARTTLS  even  if  the  PRNG  for
              OpenSSL  is  not  properly  seeded despite the
              security problems.

         LinkedAliasFileInWritableDir
              Allow an alias  file  that  is  a  link  in  a
              writable directory.

         LinkedClassFileInWritableDir
              Allow  class  files that are links in writable
              directories.

         LinkedForwardFileInWritableDir
              Allow  .forward  files  that  are   links   in
              writable directories.

         LinkedIncludeFileInWritableDir
              Allow   :include:  files  that  are  links  in
              writable directories.

         LinkedMapInWritableDir
              Allow map files that  are  links  in  writable
              directories.   This  includes  alias  database
              files.

         LinkedServiceSwitchFileInWritableDir
              Allow the service switch file  to  be  a  link
              even if the directory is writable.










SMM:08-54          Sendmail Installation and Operation Guide


         MapInUnsafeDirPath
              Allow  maps (e.g., hash, btree, and dbm files)
              in unsafe directories.   This  includes  alias
              database files.

         NonRootSafeAddr
              Do  not  mark  file  and program deliveries as
              unsafe if sendmail is not  running  with  root
              privileges.

         RunProgramInUnsafeDirPath
              Run  programs that are in writable directories
              without logging a warning.

         RunWritableProgram
              Run programs that are group- or world-writable
              without logging a warning.

         TrustStickyBit
              Allow  group  or world writable directories if
              the sticky bit is set on  the  directory.   Do
              not set this on systems which do not honor the
              sticky bit on directories.

         WorldWritableAliasFile
              Accept world-writable alias files.

         WorldWritableForwardfile
              Allow world writable .forward files.

         WorldWritableIncludefile
              Allow world wriable :include: files.

         WriteMapToHardLink
              Allow writes to maps that are hard links.

         WriteMapToSymLink
              Allow writes to maps that are symbolic links.

         WriteStatsToHardLink
              Allow the status file to be a hard link.

         WriteStatsToSymLink
              Allow the status file to be a symbolic link.

   4.10.  Connection Caching

           When processing the queue, sendmail will  try  to
      keep  the  last  few  open  connections  open to avoid
      startup and shutdown costs.  This only applies to  IPC
      and LPC connections.












Sendmail Installation and Operation Guide          SMM:08-55


           When  trying  to  open  a connection the cache is
      first searched.  If an open connection is found, it is
      probed  to see if it is still active by sending a RSET
      command.  It is not an error if this  fails;  instead,
      the connection is closed and reopened.

           Two parameters control the connection cache.  The
      ConnectionCacheSize (k) option defines the  number  of
      simultaneous  open connections that will be permitted.
      If it is set to zero, connections will  be  closed  as
      quickly as possible.  The default is one.  This should
      be set as appropriate for your system  size;  it  will
      limit  the  amount  of  system resources that sendmail
      will use during queue runs.   Never  set  this  higher
      than 4.

           The  ConnectionCacheTimeout  (K) option specifies
      the maximum time that any cached  connection  will  be
      permitted  to  idle.   When the idle time exceeds this
      value the connection is closed.  This number should be
      small (under ten minutes) to prevent you from grabbing
      too many resources from other hosts.  The  default  is
      five minutes.

   4.11.  Name Server Access

           Control  of  host  address  lookups is set by the
      hosts service entry in your service switch  file.   If
      you  are  on a system that has built-in service switch
      support (e.g., Ultrix, Solaris,  or  DEC  OSF/1)  then
      your  system  is probably configured properly already.
      Otherwise,   sendmail   will    consult    the    file
      /etc/mail/service.switch,  which  should  be  created.
      Sendmail only uses two  entries:  hosts  and  aliases,
      although   system  routines  may  use  other  services
      (notably the passwd service for user name  lookups  by
      getpwname).

           However, some systems (such as SunOS 4.X) will do
      DNS lookups regardless of the setting of  the  service
      switch entry.  In particular, the system routine geth-
      ostbyname(3) is used to look up host names,  and  many
      vendor  versions try some combination of DNS, NIS, and
      file lookup in /etc/hosts without consulting a service
      switch.  Sendmail makes no attempt to work around this
      problem, and the DNS lookup will be done  anyway.   If
      you  do  not have a nameserver configured at all, such
      as at a UUCP-only site, sendmail will get  a  "connec-
      tion  refused" message when it tries to connect to the
      name server.  If the hosts switch entry has  the  ser-
      vice "dns" listed somewhere in the list, sendmail will
      interpret this to mean a temporary  failure  and  will
      queue  the  mail  for  later processing; otherwise, it










SMM:08-56          Sendmail Installation and Operation Guide


      ignores the name server data.

           The same technique is used to decide  whether  to
      do  MX lookups.  If you want MX support, you must have
      "dns" listed as a service in the hosts switch entry.

           The ResolverOptions  (I)  option  allows  you  to
      tweak  name  server options.  The command line takes a
      series of flags as documented in resolver(3) (with the
      leading  "RES_"  deleted).  Each can be preceded by an
      optional `+' or `-'.  For example, the line

          O ResolverOptions=+AAONLY -DNSRCH

      turns on  the  AAONLY  (accept  authoritative  answers
      only)  and  turns  off  the  DNSRCH (search the domain
      path)  options.   Most  resolver   libraries   default
      DNSRCH,  DEFNAMES, and RECURSE flags on and all others
      off.  If NETINET6 is enabled, most  libraries  default
      to  USE_INET6 as well.  You can also include "HasWild-
      cardMX" to specify that there is a wildcard MX  record
      matching  your domain; this turns off MX matching when
      canonifying names, which  can  lead  to  inappropriate
      canonifications.    Use   "WorkAroundBrokenAAAA"  when
      faced with a broken nameserver that  returns  SERVFAIL
      (a  temporary failure) on T_AAAA (IPv6) lookups during
      hostname canonification.  Notice: it might  be  neces-
      sary  to  apply  the same (or similar) options to sub-
      mit.cf too.

           Version level 1 configurations (see  the  section
      about ``Configuration Version Level'') turn DNSRCH and
      DEFNAMES off when doing delivery  lookups,  but  leave
      them  on  everywhere  else.   Version  8  of  sendmail
      ignores them when doing canonification  lookups  (that
      is, when using $[ ... $]), and always does the search.
      If you don't want  to  do  automatic  name  extension,
      don't call $[ ... $].

           The  search rules for $[ ... $] are somewhat dif-
      ferent than usual.  If the name being looked up has at
      least  one  dot,  it  always tries the unmodified name
      first.  If that fails, it  tries  the  reduced  search
      path,  and  lastly tries the unmodified name (but only
      for names without a dot, since names with a  dot  have
      already  been  tried).   This  allows  names  such  as
      ``utc.CS'' to match the site in Czechoslovakia  rather
      than  the  site in your local Computer Science depart-
      ment.  It also prefers A and  CNAME  records  over  MX
      records  -- that is, if it finds an MX record it makes
      note of it, but keeps looking.  This way, if you  have
      a wildcard MX record matching your domain, it will not
      assume that all names match.










Sendmail Installation and Operation Guide          SMM:08-57


           To completely turn off all name server access  on
      systems  without service switch support (such as SunOS
      4.X) you will have to  recompile  with  -DNAMED_BIND=0
      and  remove  -lresolv from the list of libraries to be
      searched when linking.

   4.12.  Moving the Per-User Forward Files

           Some sites mount each user's home directory  from
      a  local  disk  on  their  workstation,  so that local
      access is fast.  However, the result is that  .forward
      file  lookups from a central mail server are slow.  In
      some cases, mail can even  be  delivered  on  machines
      inappropriately  because  of a file server being down.
      The performance can be especially bad if you  run  the
      automounter.

           The  ForwardPath  (J)  option allows you to set a
      path of forward files.  For example, the  config  file
      line

          O ForwardPath=/var/forward/$u:$z/.forward.$w

      would  first look for a file with the same name as the
      user's login in /var/forward; if that is not found (or
      is  inaccessible) the file ``.forward.machinename'' in
      the user's home directory is searched.  A  truly  per-
      verse  site  could  also search by sender by using $r,
      $s, or $f.

           If you create a directory such  as  /var/forward,
      it should be mode 1777 (that is, the sticky bit should
      be set).  Users should create  the  files  mode  0644.
      Note  that you must use the ForwardFileInUnsafeDirPath
      and  ForwardFileInUnsafeDirPathSafe  flags  with   the
      DontBlameSendmail  option  to allow forward files in a
      world writable directory.  This might also be used  as
      a denial of service attack (users could create forward
      files for other users); a better approach might be  to
      create  /var/forward  mode 0755 and create empty files
      for each user, owned by that user, mode 0644.  If  you
      do  this,  you don't have to set the DontBlameSendmail
      options indicated above.

   4.13.  Free Space

           On systems that have one of the system  calls  in
      the  statfs(2)  family  (including statvfs and ustat),
      you can specify a minimum number of free blocks on the
      queue  filesystem  using the MinFreeBlocks (b) option.
      If there are fewer than the indicated number of blocks
      free  on  the filesystem on which the queue is mounted
      the SMTP server will reject mail with  the  452  error










SMM:08-58          Sendmail Installation and Operation Guide


      code.   This  invites  the  SMTP  client  to try again
      later.

           Beware of setting this option too  high;  it  can
      cause  rejection of email when that mail would be pro-
      cessed without difficulty.

   4.14.  Maximum Message Size

           To avoid overflowing your  system  with  a  large
      message,  the  MaxMessageSize option can be set to set
      an absolute limit on the  size  of  any  one  message.
      This  will  be  advertised  in  the ESMTP dialogue and
      checked during message collection.

   4.15.  Privacy Flags

           The PrivacyOptions (p) option allows you  to  set
      certain  ``privacy''  flags.   Actually,  many of them
      don't give you any extra privacy, rather just  insist-
      ing  that  client  SMTP  servers  use the HELO command
      before using certain commands or adding extra  headers
      to indicate possible spoof attempts.

           The  option  takes  a  series  of flag names; the
      final privacy is the inclusive or of those flags.  For
      example:

          O PrivacyOptions=needmailhelo, noexpn

      insists that the HELO or EHLO command be used before a
      MAIL command is accepted and disables  the  EXPN  com-
      mand.

           The flags are detailed in section 5.6.

   4.16.  Send to Me Too

           Beginning with version 8.10, sendmail includes by
      default the (envelope) sender in any list  expansions.
      For  example,  if "matt" sends to a list that contains
      "matt" as one of the members he will get a copy of the
      message.   If the MeToo option is set to FALSE (in the
      configuration file or  via  the  command  line),  this
      behavior  is  changed,  i.e., the (envelope) sender is
      excluded in list expansions.

5.  THE WHOLE SCOOP ON THE CONFIGURATION FILE

        This section describes  the  configuration  file  in
   detail.












Sendmail Installation and Operation Guide          SMM:08-59


        There is one point that should be made clear immedi-
   ately: the syntax of the configuration file  is  designed
   to  be reasonably easy to parse, since this is done every
   time sendmail starts up, rather than easy for a human  to
   read  or  write.  The configuration file should be gener-
   ated via the method described in cf/README, it should not
   be  edited  directly  unless someone is familiar with the
   internals of the syntax described here and it is not pos-
   sible  to  achieve  the  desired  result  via the default
   method.

        The configuration file is organized as a  series  of
   lines,  each  of  which  begins  with  a single character
   defining the semantics for the rest of the  line.   Lines
   beginning  with  a  space or a tab are continuation lines
   (although the semantics are  not  well  defined  in  many
   places).   Blank  lines  and lines beginning with a sharp
   symbol (`#') are comments.

   5.1.  R and S -- Rewriting Rules

           The core of address  parsing  are  the  rewriting
      rules.  These are an ordered production system.  Send-
      mail scans through the set of rewriting rules  looking
      for  a  match on the left hand side (LHS) of the rule.
      When a rule matches, the address is  replaced  by  the
      right hand side (RHS) of the rule.

           There  are several sets of rewriting rules.  Some
      of the rewriting sets are  used  internally  and  must
      have  specific semantics.  Other rewriting sets do not
      have specifically assigned semantics, and may be  ref-
      erenced  by the mailer definitions or by other rewrit-
      ing sets.

           The syntax of these two commands are:

          Sn

      Sets the current ruleset being collected to n.  If you
      begin  a  ruleset more than once it appends to the old
      definition.

          Rlhs rhs comments

      The fields must be separated by at least one tab char-
      acter;  there  may  be  embedded spaces in the fields.
      The lhs is a pattern that is applied to the input.  If
      it  matches,  the  input is rewritten to the rhs.  The
      comments are ignored.

           Macro expansions of the  form  $x  are  performed
      when  the configuration file is read.  A literal $ can










SMM:08-60          Sendmail Installation and Operation Guide


      be included using $$.  Expansions of the form $&x  are
      performed  at  run  time using a somewhat less general
      algorithm.  This  is  intended  only  for  referencing
      internally  defined macros such as $h that are changed
      at runtime.

      5.1.1.  The left hand side

              The left hand side of rewriting rules contains
         a   pattern.    Normal  words  are  simply  matched
         directly.  Metasyntax is introduced using a  dollar
         sign.  The metasymbols are:

             $*   Match zero or more tokens
             $+   Match one or more tokens
             $-   Match exactly one token
             $=x  Match any phrase in class x
             $~x  Match any word not in class x

         If  any  of  these  match, they are assigned to the
         symbol $n for replacement on the right  hand  side,
         where  n  is the index in the LHS.  For example, if
         the LHS:

             $-:$+

         is applied to the input:

             UCBARPA:eric

         the rule will match, and the values passed  to  the
         RHS will be:

             $1  UCBARPA
             $2  eric


              Additionally,  the LHS can include $@ to match
         zero tokens.  This is not bound to a $n on the RHS,
         and  is  normally only used when it stands alone in
         order to match the null input.

      5.1.2.  The right hand side

              When the left hand side of  a  rewriting  rule
         matches,  the  input is deleted and replaced by the
         right hand side.  Tokens are copied  directly  from
         the  RHS  unless  they  begin  with  a dollar sign.
         Metasymbols are:














Sendmail Installation and Operation Guide          SMM:08-61


             $n         Substitute indefinite token n from LHS
             $[name$]   Canonicalize name
             $(map key $@arguments $:default $)
                        Generalized keyed mapping function
             $>n        "Call" ruleset n
             $#mailer   Resolve to mailer
             $@host     Specify host
             $:user     Specify user


              The $n syntax  substitutes  the  corresponding
         value  from  a  $+,  $-, $*, $=, or $~ match on the
         LHS.  It may be used anywhere.

              A host name enclosed  between  $[  and  $]  is
         looked  up  in the host database(s) and replaced by
         the  canonical  name[14].   For  example, "$[ftp$]"
         might     become     "ftp.CS.Berkeley.EDU"      and
         "$[[128.32.130.2]$]"     would     become     "van-
         gogh.CS.Berkeley.EDU."   Sendmail  recognizes   its
         numeric  IP address without calling the name server
         and replaces it with its canonical name.

              The $( ...  $) syntax is a more  general  form
         of  lookup;  it  uses  a  named  map  instead of an
         implicit map.  If no lookup is found, the indicated
         default is inserted; if no default is specified and
         no lookup matches, the  value  is  left  unchanged.
         The  arguments  are  passed to the map for possible
         use.

              The $>n syntax causes  the  remainder  of  the
         line  to be substituted as usual and then passed as
         the argument to ruleset  n.   The  final  value  of
         ruleset  n  then  becomes the substitution for this
         rule.  The $> syntax expands everything  after  the
         ruleset  name  to the end of the replacement string
         and then passes that as the initial  input  to  the
         ruleset.   Recursive  calls are allowed.  For exam-
         ple,

             $>0 $>3 $1

         expands $1, passes that  to  ruleset  3,  and  then
         passes the result of ruleset 3 to ruleset 0.

              The  $#  syntax should only be used in ruleset
         zero, a subroutine of  ruleset  zero,  or  rulesets
____________________
   [14]This is  actually  completely  equivalent  to  $(host
hostname$).  In particular, a $: default can be used.












SMM:08-62          Sendmail Installation and Operation Guide


         that   return  decisions  (e.g.,  check_rcpt).   It
         causes evaluation of the ruleset to terminate imme-
         diately,  and  signals to sendmail that the address
         has completely resolved.  The complete  syntax  for
         ruleset 0 is:

             $#mailer $@host $:user

         This  specifies  the  {mailer,  host, user} 3-tuple
         necessary to direct the mailer.   Note:  the  third
         element ( user ) is often also called address part.
         If the mailer is local the host part may  be  omit-
         ted[15].  The mailer must be a single word, but the
         host  and user may be multi-part.  If the mailer is
         the built-in IPC mailer, the host may be  a  colon-
         separated  list of hosts that are searched in order
         for the first  working  address  (exactly  like  MX
         records).   The  user  is  later  rewritten  by the
         mailer-specific envelope rewriting set and assigned
         to  the $u macro.  As a special case, if the mailer
         specified has the F=@ flag specified and the  first
         character  of  the  $:  value  is  "@",  the "@" is
         stripped off, and a flag  is  set  in  the  address
         descriptor that causes sendmail to not do ruleset 5
         processing.

              Normally, a rule that matches is retried, that
         is,  the rule loops until it fails.  A RHS may also
         be preceded by a $@ or a $: to change  this  behav-
         ior.  A $@ prefix causes the ruleset to return with
         the remainder of the RHS as the value.  A $: prefix
         causes  the  rule to terminate immediately, but the
         ruleset to continue; this can be used to avoid con-
         tinued  application  of  a  rule.   The  prefix  is
         stripped before continuing.

              The $@ and $: prefixes may precede a $>  spec;
         for example:

             R$+     $: $>7 $1

         matches anything, passes that to ruleset seven, and
         continues; the $: is necessary to avoid an infinite
         loop.


____________________
   [15]You  may want to use it for special "per user" exten-
sions.  For example, in the address  "jgm+foo@CMU.EDU";  the
"+foo"  part  is not part of the user name, and is passed to
the local mailer for local use.












Sendmail Installation and Operation Guide          SMM:08-63


              Substitution  occurs  in  the order described,
         that is, parameters from the LHS  are  substituted,
         hostnames   are  canonicalized,  "subroutines"  are
         called, and finally $#, $@, and $: are processed.

      5.1.3.  Semantics of rewriting rule sets

              There are six rewriting sets  that  have  spe-
         cific  semantics.   Five  of  these  are related as
         depicted by figure 1.

              Ruleset three should  turn  the  address  into
         "canonical  form."  This form should have the basic
         syntax:

             local-part@host-domain-spec

         Ruleset three is applied by sendmail  before  doing
         anything with any address.

              If  no  "@"  sign is specified, then the host-
         domain-spec may be appended (box "D" in  Figure  1)
         from  the  sender  address (if the C flag is set in
         the mailer definition corresponding to the  sending
         mailer).

              Ruleset zero is applied after ruleset three to
         addresses that are going to actually specify recip-
         ients.    It  must  resolve  to  a  {mailer,  host,
         address} triple.  The mailer must be defined in the

____________________________________________________________

                    +---+
                 -->| 0 |-->resolved address
                /   +---+
               /            +---+   +---+
              /        ---->| 1 |-->| S |--
       +---+ / +---+  /     +---+   +---+  \    +---+
addr-->| 3 |-->| D |--                      --->| 4 |-->msg
       +---+   +---+  \     +---+   +---+  /    +---+
                        --->| 2 |-->| R |--
                            +---+   +---+

            Figure 1 -- Rewriting set semantics
          D -- sender domain addition
          S -- mailer-specific sender rewriting
          R -- mailer-specific recipient rewriting
____________________________________________________________














SMM:08-64          Sendmail Installation and Operation Guide


         mailer  definitions  from  the  configuration file.
         The host is defined into the $h macro  for  use  in
         the   argv   expansion  of  the  specified  mailer.
         Notice: since the envelope sender address  will  be
         used  if  a  delivery  status  notification must be
         send, i.e., is may specify a recipient, it is  also
         run  through ruleset zero.  If ruleset zero returns
         a temporary error 4xy then  delivery  is  deferred.
         This  can  be used to temporarily disable delivery,
         e.g., based on the time of the day or other varying
         parameters.  It should not be used to quarantine e-
         mails.

              Rulesets one and two are applied to all sender
         and  recipient  addresses  respectively.   They are
         applied before any specification in the mailer def-
         inition.  They must never resolve.

              Ruleset  four  is  applied to all addresses in
         the message.  It is  typically  used  to  translate
         internal to external form.

              In addition, ruleset 5 is applied to all local
         addresses (specifically, those that  resolve  to  a
         mailer  with  the  `F=5' flag set) that do not have
         aliases.  This allows a last minute hook for  local
         names.

      5.1.4.  Ruleset hooks

              A  few  extra  rulesets are defined as "hooks"
         that can be defined to get special features.   They
         are  all  named  rulesets.  The "check_*" forms all
         give accept/reject status; falling off the  end  or
         returning  normally  is an accept, and resolving to
         $#error is a reject or quarantine.  Quarantining is
         chosen  by specifying quarantine in the second part
         of the mailer triplet:

             $#error $@ quarantine $: Reason for quarantine

         Many of these  can  also  resolve  to  the  special
         mailer  name $#discard; this accepts the message as
         though it were  successful  but  then  discards  it
         without delivery.  Note, this mailer cannot be cho-
         sen as a mailer in ruleset 0.  Note also  that  all
         "check_*"  rulesets  have  to  deal  with temporary
         failures, especially for map  lookups,  themselves,
         i.e.,  they should return a temporary error code or
         at least they should  make  a  proper  decision  in
         those cases.












Sendmail Installation and Operation Guide          SMM:08-65


         5.1.4.1.  check_relay

                 The  check_relay  ruleset is called after a
            connection is accepted by the daemon.  It is not
            called  when  sendmail  is started using the -bs
            option.  It is passed

                client.host.name $| client.host.address

            where $| is a metacharacter separating  the  two
            parts.  This ruleset can reject connections from
            various locations.  Note that it only checks the
            connecting  SMTP client IP address and hostname.
            It does not check for third party message relay-
            ing.   The  check_rcpt  ruleset  discussed below
            usually does third party message relay checking.

         5.1.4.2.  check_mail

                 The check_mail ruleset is passed  the  user
            name parameter of the SMTP MAIL command.  It can
            accept or reject the address.

         5.1.4.3.  check_rcpt

                 The check_rcpt ruleset is passed  the  user
            name parameter of the SMTP RCPT command.  It can
            accept or reject the address.

         5.1.4.4.  check_data

                 The check_data ruleset is called after  the
            SMTP  DATA  command, its parameter is the number
            of recipients.  It can accept or reject the com-
            mand.

         5.1.4.5.  check_compat

                 The check_compat ruleset is passed

                sender-address $| recipient-address

            where  $|  is  a  metacharacter  separating  the
            addresses.  It can accept or reject mail  trans-
            fer  between  these  two addresses much like the
            checkcompat()  function.   Note:   while   other
            check_*  rulesets  are  invoked  during the SMTP
            mail  receiption  stage  (i.e.,  in   the   SMTP
            server), check_compat is invoked during the mail
            delivery stage.













SMM:08-66          Sendmail Installation and Operation Guide


         5.1.4.6.  check_eoh

                 The check_eoh ruleset is passed

                number-of-headers $| size-of-headers

            where $| is a metacharacter separating the  num-
            bers.   These  numbers can be used for size com-
            parisons with the arith  map.   The  ruleset  is
            triggered  after  all  of  the headers have been
            read.  It can be used to  correlate  information
            gathered  from  those  headers  using  the macro
            storage map.  One possible use is to check for a
            missing header.  For example:

                Kstorage macro
                HMessage-Id: $>CheckMessageId

                SCheckMessageId
                # Record the presence of the header
                R$*            $: $(storage {MessageIdCheck} $@ OK $) $1
                R< $+ @ $+ >   $@ OK
                R$*            $#error $: 553 Header Error

                Scheck_eoh
                # Check the macro
                R$*            $: < $&{MessageIdCheck} >
                # Clear the macro for the next message
                R$*            $: $(storage {MessageIdCheck} $) $1
                # Has a Message-Id: header
                R< $+ >        $@ OK
                # Allow missing Message-Id: from local mail
                R$*            $: < $&{client_name} >
                R< >           $@ OK
                R< $=w >       $@ OK
                # Otherwise, reject the mail
                R$*            $#error $: 553 Header Error

            Keep  in  mind  the  Message-Id: header is not a
            required header and is  not  a  guaranteed  spam
            indicator.   This  ruleset  is  an  example  and
            should probably not be used in production.

         5.1.4.7.  check_eom

                 The check_eom ruleset is called  after  the
            end  of  a message, its parameter is the message
            size.  It can accept or reject the message.

         5.1.4.8.  check_etrn

                 The check_etrn ruleset is passed the param-
            eter of the SMTP ETRN command.  It can accept or










Sendmail Installation and Operation Guide          SMM:08-67


            reject the command.

         5.1.4.9.  check_expn

                 The check_expn ruleset is passed  the  user
            name parameter of the SMTP EXPN command.  It can
            accept or reject the address.

         5.1.4.10.  check_vrfy

                 The check_vrfy ruleset is passed  the  user
            name parameter of the SMTP VRFY command.  It can
            accept or reject the command.

         5.1.4.11.  trust_auth

                 The trust_auth ruleset is passed the  AUTH=
            parameter  of the SMTP MAIL command.  It is used
            to  determine  whether  this  value  should   be
            trusted.  In  order  to  make this decision, the
            ruleset may make use of  the  various  ${auth_*}
            macros.   If  the  ruleset  does  resolve to the
            "error"  mailer  the  AUTH=  parameter  is   not
            trusted  and  hence  not  passed  on to the next
            relay.

         5.1.4.12.  tls_client

                 The tls_client ruleset is called when send-
            mail  acts  as  server, after a STARTTLS command
            has  been  issued,  and  from  check_mail.   The
            parameter is the value of ${verify} and STARTTLS
            or MAIL,  respectively.   If  the  ruleset  does
            resolve  to  the "error" mailer, the appropriate
            error code is returned to the client.

         5.1.4.13.  tls_server

                 The tls_server ruleset is called when send-
            mail  acts  as  client  after a STARTTLS command
            (should) have been issued.  The parameter is the
            value of ${verify}.  If the ruleset does resolve
            to the "error" mailer, the connection is aborted
            (treated  as non-deliverable with a permanent or
            temporary error).

         5.1.4.14.  tls_rcpt

                 The tls_rcpt ruleset is  called  each  time
            before a RCPT TO command is sent.  The parameter
            is the current recipient.  If the  ruleset  does
            resolve  to the "error" mailer, the RCPT TO com-
            mand is suppressed (treated  as  non-deliverable










SMM:08-68          Sendmail Installation and Operation Guide


            with  a  permanent  or  temporary  error).  This
            ruleset allows to require encryption or  verifi-
            cation  of  the recipient's MTA even if the mail
            is somehow  redirected  to  another  host.   For
            example,  sending  mail  to luke@endmail.org may
            get redirected to a host  named  death.star  and
            hence  the  tls_server  ruleset won't apply.  By
            introducing  per  recipient  restrictions   such
            attacks  (e.g.,  via  DNS  spoofing) can be made
            impossible.  See cf/README how this ruleset  can
            be used.

         5.1.4.15.  srv_features

                 The srv_features ruleset is called with the
            connecting client's host name when a client con-
            nects  to  sendmail.  This ruleset should return
            $# followed by a list of options (single charac-
            ters  delimited  by white space).  If the return
            value starts with anything else it  is  silently
            ignored.   Generally  upper case characters turn
            off a feature while lower case  characters  turn
            it  on.   Option  `S'  causes  the server not to
            offer STARTTLS, which is useful to interact with
            MTAs/MUAs  that have broken STARTTLS implementa-
            tions by simply not offering it.  `V' turns  off
            the  request for a client certificate during the
            TLS handshake.  Options  `A'  and  `P'  suppress
            SMTP  AUTH and PIPELINING, respectively.  `c' is
            the  equivalent  to  AuthOptions=p,   i.e.,   it
            doesn't  permit mechanisms susceptible to simple
            passive attack (e.g., PLAIN,  LOGIN),  unless  a
            security  layer  is active.  Option `l' requires
            SMTP AUTH for a connection.  Options  'B',  'D',
            'E',  and 'X' suppress SMTP VERB, DSN, ETRN, and
            EXPN, respectively.



























Sendmail Installation and Operation Guide          SMM:08-69


                A        Do not offer AUTH
                a        Offer AUTH (default)
                B        Do not offer VERB
                b        Offer VERB (default)
                C        Do not require security layer for
                         plaintext AUTH (default)
                c        Require security layer for plaintext AUTH
                D        Do not offer DSN
                d        Offer DSN (default)
                E        Do not offer ETRN
                e        Offer ETRN (default)
                L        Do not require AUTH (default)
                l        Require AUTH
                P        Do not offer PIPELINING
                p        Offer PIPELINING (default)
                S        Do not offer STARTTLS
                s        Offer STARTTLS (default)
                V        Do not request a client certificate
                v        Request a client certificate (default)
                X        Do not offer EXPN
                x        Offer EXPN (default)

            Note: the entries marked  as  ``(default)''  may
            require  that  some configuration has been made,
            e.g., SMTP AUTH is only  available  if  properly
            configured.    Moreover,  many  options  can  be
            changed on a global basis via other settings  as
            explained in this document, e.g., via DaemonPor-
            tOptions.

                 The ruleset may return `$#temp' to indicate
            that  there  is  a temporary problem determining
            the correct features, e.g., if a map is unavail-
            able.   In  that  case, the SMTP server issues a
            temporary failure and does not accept email.

         5.1.4.16.  try_tls

                 The try_tls ruleset is called when sendmail
            connects  to  another  MTA.  If the ruleset does
            resolve to the "error" mailer, sendmail does not
            try  STARTTLS  even  if  it is offered.  This is
            useful to interact with MTAs  that  have  broken
            STARTTLS implementations by simply not using it.

         5.1.4.17.  authinfo

                 The  authinfo  ruleset is called when send-
            mail tries to authenticate to another  MTA.   It
            should  return  $#  followed by a list of tokens
            that are used for  SMTP  AUTH.   If  the  return
            value  starts  with anything else it is silently
            ignored.  Each token is a tagged string  of  the










SMM:08-70          Sendmail Installation and Operation Guide


            form: "TDstring" (including the quotes), where

                T        Tag which describes the item
                D        Delimiter: ':' simple text follows
                         '=' string is base64 encoded
                string   Value of the item

            Valid values for the tag are:

                U        user (authorization) id
                I        authentication id
                P        password
                R        realm
                M        list of mechanisms delimited by spaces

            If  this ruleset is defined, the option Default-
            AuthInfo is ignored (even if  the  ruleset  does
            not return a ``useful'' result).

         5.1.4.18.  queuegroup

                 The  queuegroup  ruleset  is  used to map a
            recipient address to a queue  group  name.   The
            input  for the ruleset is a recipient address as
            specified by the SMTP RCPT command.  The ruleset
            should return $# followed by the name of a queue
            group.  If the return value starts with anything
            else  it  is  silently ignored.  See the section
            about ``Queue Groups and Queue Directories'' for
            further information.

         5.1.4.19.  greet_pause

                 The  greet_pause ruleset is used to specify
            the amount of time to pause before  sending  the
            initial  SMTP  220  greeting.  If any traffic is
            received during that pause, an SMTP  554  rejec-
            tion response is given instead of the 220 greet-
            ing and all SMTP commands  are  rejected  during
            that  connection.  This helps protect sites from
            open proxies and  SMTP  slammers.   The  ruleset
            should  return $# followed by the number of mil-
            liseconds (thousandths of a  second)  to  pause.
            If the return value starts with anything else or
            is not a number, it is silently ignored.   Note:
            this  ruleset is not invoked (and hence the fea-
            ture is disabled) when the smtps (SMTP over SSL)
            is  used,  i.e.,  the  s modifier is set for the
            daemon via DaemonPortOptions,  because  in  this
            case  the  SSL handshake is performed before the
            greeting is sent.












Sendmail Installation and Operation Guide          SMM:08-71


      5.1.5.  IPC mailers

              Some special processing occurs if the  ruleset
         zero  resolves  to an IPC mailer (that is, a mailer
         that has "[IPC]" listed as the Path in the  M  con-
         figuration  line.   The host name passed after "$@"
         has MX expansion performed if not delivering via  a
         named socket; this looks the name up in DNS to find
         alternate delivery sites.

              The host name can also be provided as a dotted
         quad  or  an  IPv6  address in square brackets; for
         example:

             [128.32.149.78]

         or

             [IPv6:2002:c0a8:51d2::23f4]

         This causes direct conversion of the numeric  value
         to an IP host address.

              The  host  name  passed  in after the "$@" may
         also be a colon-separated list of hosts.   Each  is
         separately MX expanded and the results are concate-
         nated to make (essentially) one long MX list.   The
         intent here is to create "fake" MX records that are
         not published in DNS for private internal networks.

              As a final special case, the host name can  be
         passed in as a text string in square brackets:

             [ucbvax.berkeley.edu]

         This  form  avoids  the  MX mapping.  N.B.: This is
         intended only for situations where you have a  net-
         work  firewall  or  other host that will do special
         processing for all  your  mail,  so  that  your  MX
         record  points  to  a gateway machine; this machine
         could then do direct delivery  to  machines  within
         your  local  domain.   Use of this feature directly
         violates RFC 1123 section 5.3.5: it should  not  be
         used lightly.

   5.2.  D -- Define Macro

           Macros  are named with a single character or with
      a word in  {braces}.   The  names  ``x''  and  ``{x}''
      denote  the  same  macro  for  every  single character
      ``x''.  Single character names may  be  selected  from
      the  entire  ASCII set, but user-defined macros should
      be selected from the set of upper case  letters  only.










SMM:08-72          Sendmail Installation and Operation Guide


      Lower case letters and special symbols are used inter-
      nally.  Long names beginning with a lower case  letter
      or  a  punctuation  character  are reserved for use by
      sendmail, so  user-defined  long  macro  names  should
      begin with an upper case letter.

           The syntax for macro definitions is:

          Dxval

      where  x is the name of the macro (which may be a sin-
      gle character or a word in  braces)  and  val  is  the
      value it should have.  There should be no spaces given
      that do not actually belong in the macro value.

           Macros are interpolated using the  construct  $x,
      where  x  is the name of the macro to be interpolated.
      This interpolation is done when the configuration file
      is read, except in M lines.  The special construct $&x
      can be used in R lines to get deferred interpolation.

           Conditionals can be specified using the syntax:

          $?x text1 $| text2 $.

      This interpolates text1 if the macro  $x  is  set  and
      non-null, and text2 otherwise.  The "else" ($|) clause
      may be omitted.

           The following  macros  are  defined  and/or  used
      internally  by  sendmail for interpolation into argv's
      for mailers or for other contexts.  The ones marked  *
      are  information  passed  into  sendmail[16], the ones
      marked # are information passed both  in  and  out  of
      sendmail,  and  the  unmarked macros are passed out of
      sendmail but are not otherwise used internally.  These
      macros are:

      $a   The  origination date in RFC 822 format.  This is
           extracted from the Date: line.

      $b   The current date in RFC 822 format.

      $c   The hop count.  This is a count of the number  of
           Received:  lines plus the value of the -h command
           line flag.

____________________
   [16]As  of  version 8.6, all of these macros have reason-
able defaults.  Previous versions required that they be  de-
fined.












Sendmail Installation and Operation Guide          SMM:08-73


      $d   The current date in UNIX (ctime) format.

      $e*  (Obsolete;   use    SmtpGreetingMessage    option
           instead.)   The  SMTP  entry  message.   This  is
           printed out when SMTP starts up.  The first  word
           must  be  the  $j  macro as specified by RFC 821.
           Defaults to "$j Sendmail $v ready at  $b".   Com-
           monly redefined to include the configuration ver-
           sion number, e.g., "$j Sendmail  $v/$Z  ready  at
           $b"

      $f   The envelope sender (from) address.

      $g   The  sender  address  relative  to the recipient.
           For  example,  if  $f  is  "foo",  $g   will   be
           "host!foo",  "foo@host.domain",  or  whatever  is
           appropriate for the receiving mailer.

      $h   The recipient host.  This is  set  in  ruleset  0
           from the $@ field of a parsed address.

      $i   The queue id, e.g., "f344MXxp018717".

      $j#  The  "official"  domain name for this site.  This
           is fully qualified if the full qualification  can
           be  found.   It must be redefined to be the fully
           qualified domain name if your system is not  con-
           figured so that information can find it automati-
           cally.

      $k   The UUCP node name (from the uname system call).

      $l*  (Obsolete; use UnixFromLine option instead.)  The
           format  of  the  UNIX from line.  Unless you have
           changed the UNIX mailbox format, you  should  not
           change the default, which is "From $g $d".

      $m   The  domain part of the gethostname return value.
           Under normal circumstances, $j is  equivalent  to
           $w.$m.

      $n*  The  name  of  the  daemon  (for error messages).
           Defaults to "MAILER-DAEMON".

      $o*  (Obsolete:  use  OperatorChars  option  instead.)
           The  set  of "operators" in addresses.  A list of
           characters which will be  considered  tokens  and
           which  will  separate  tokens when doing parsing.
           For example, if "@" were in the  $o  macro,  then
           the input "a@b" would be scanned as three tokens:
           "a," "@," and "b."  Defaults to ".:@[]", which is
           the  minimum set necessary to do RFC 822 parsing;
           a richer set of operators  is  ".:%@!/[]",  which










SMM:08-74          Sendmail Installation and Operation Guide


           adds  support  for  UUCP,  the  %-hack, and X.400
           addresses.

      $p   Sendmail's process id.

      $q*  Default format of sender address.  The  $q  macro
           specifies  how an address should appear in a mes-
           sage when it is defaulted.  Defaults  to  "<$g>".
           It is commonly redefined to be "$?x$x <$g>$|$g$."
           or "$g$?x ($x)$.", corresponding to the following
           two formats:

               Eric Allman <eric@CS.Berkeley.EDU>
               eric@CS.Berkeley.EDU (Eric Allman)

           Sendmail  properly quotes names that have special
           characters if the first form is used.

      $r   Protocol used to receive the message.   Set  from
           the  -p  command  line flag or by the SMTP server
           code.

      $s   Sender's host name.  Set from the -p command line
           flag or by the SMTP server code (in which case it
           is set to the EHLO/HELO parameter).

      $t   A numeric representation of the current  time  in
           the  format YYYYMMDDHHmm (4 digit year 1900-9999,
           2 digit month 01-12, 2 digit day 01-31,  2  digit
           hours 00-23, 2 digit minutes 00-59).

      $u   The recipient user.

      $v   The version number of the sendmail binary.

      $w#  The hostname of this site.  This is the root name
           of this host (but see below for caveats).

      $x   The full name of the sender.

      $z   The home directory of the recipient.

      $_   The   validated   sender   address.    See   also
           ${client_resolve}.

      ${addr_type}
           The  type of the address which is currently being
           rewritten.  This macro contains up to three char-
           acters,  the first is either `e' or `h' for enve-
           lope/header address, the second is a  space,  and
           the third is either `s' or `r' for sender/recipi-
           ent address.











Sendmail Installation and Operation Guide          SMM:08-75


      ${alg_bits}
           The maximum keylength (in bits) of the  symmetric
           encryption  algorithm  used for a TLS connection.
           This may be less than  the  effective  keylength,
           which  is  stored in ${cipher_bits}, for ``export
           controlled'' algorithms.

      ${auth_authen}
           The client's authentication credentials as deter-
           mined by authentication (only set if successful).
           The format depends  on  the  mechanism  used,  it
           might  be  just `user', or `user@realm', or some-
           thing similar (SMTP AUTH only).

      ${auth_author}
           The authorization identity, i.e. the AUTH= param-
           eter of the SMTP MAIL command if supplied.

      ${auth_type}
           The  mechanism used for SMTP authentication (only
           set if successful).

      ${auth_ssf}
           The keylength (in bits) of the symmetric  encryp-
           tion  algorithm  used for the security layer of a
           SASL mechanism.

      ${bodytype}
           The message body  type  (7BIT  or  8BITMIME),  as
           determined from the envelope.

      ${cert_issuer}
           The  DN  (distinguished name) of the CA (certifi-
           cate authority) that signed  the  presented  cer-
           tificate (the cert issuer) (STARTTLS only).

      ${cert_md5}
           The MD5 hash of the presented certificate (START-
           TLS only).

      ${cert_subject}
           The DN of the presented certificate  (called  the
           cert subject) (STARTTLS only).

      ${cipher}
           The  cipher  suite used for the connection, e.g.,
           EDH-DSS-DES-CBC3-SHA,  EDH-RSA-DES-CBC-SHA,  DES-
           CBC-MD5, DES-CBC3-SHA (STARTTLS only).

      ${cipher_bits}
           The  effective keylength (in bits) of the symmet-
           ric encryption algorithm used for a  TLS  connec-
           tion.










SMM:08-76          Sendmail Installation and Operation Guide


      ${client_addr}
           The   IP   address  of  the  SMTP  client.   IPv6
           addresses are  tagged  with  "IPv6:"  before  the
           address.  Defined in the SMTP server only.

      ${client_connections}
           The number of open connections in the SMTP server
           for the client IP address.

      ${client_flags}
           The flags specified  by  the  Modifier=  part  of
           ClientPortOptions  where flags are separated from
           each other by spaces and  upper  case  flags  are
           doubled.   That  is,  Modifier=hA  will be repre-
           sented as "h AA"  in  ${client_flags},  which  is
           required for testing the flags in rulesets.

      ${client_name}
           The  host  name  of the SMTP client.  This may be
           the client's bracketed IP address in the  form  [
           nnn.nnn.nnn.nnn     ]     for    IPv4    and    [
           IPv6:nnnn:...:nnnn ] for IPv6 if the client's  IP
           address is not resolvable, or if it is resolvable
           but the  IP  address  of  the  resolved  hostname
           doesn't  match  the original IP address.  Defined
           in   the   SMTP   server    only.     See    also
           ${client_resolve}.

      ${client_port}
           The  port  number of the SMTP client.  Defined in
           the SMTP server only.

      ${client_ptr}
           The result of the PTR lookup for  the  client  IP
           address.     Note:    this   is   the   same   as
           ${client_name} if and only  if  ${client_resolve}
           is OK.  Defined in the SMTP server only.

      ${client_rate}
           The number of incoming connections for the client
           IP address over the time  interval  specified  by
           ConnectionRateWindowSize.

      ${client_resolve}
           Holds   the   result  of  the  resolve  call  for
           ${client_name}.  Possible values are:

               OK        resolved successfully
               FAIL      permanent lookup failure
               FORGED    forward lookup doesn't match reverse lookup
               TEMP      temporary lookup failure

           Defined  in  the  SMTP  server  only.    sendmail










Sendmail Installation and Operation Guide          SMM:08-77


           performs  a  hostname lookup on the IP address of
           the connecting client.  Next the IP addresses  of
           that  hostname  are  looked up.  If the client IP
           address does not appear in that  list,  then  the
           hostname  is  maybe forged.  This is reflected as
           the value FORGED  for  ${client_resolve}  and  it
           also shows up in $_ as "(may be forged)".

      ${cn_issuer}
           The  CN  (common  name) of the CA that signed the
           presented certificate (STARTTLS only).  Note:  if
           the  CN  cannot  be extracted properly it will be
           replaced by one of these  strings  based  on  the
           encountered error:

               BadCertificateContainsNULCN contains a NUL character
               BadCertificateTooLong    CN is too long
               BadCertificateUnknown    CN could not be extracted

           In  the  last case, some other (unspecific) error
           occurred.

      ${cn_subject}
           The CN (common name) of the presented certificate
           (STARTTLS  only).   See ${cn_issuer} for possible
           replacements.

      ${currHeader}
           Header value as quoted string (possibly truncated
           to  MAXNAME).   This  macro  is only available in
           header check rulesets.

      ${daemon_addr}
           The IP address the daemon  is  listening  on  for
           connections.

      ${daemon_family}
           The  network  family  if  the daemon is accepting
           network  connections.   Possible  values  include
           "inet", "inet6", "iso", "ns", "x.25"

      ${daemon_flags}
           The flags for the daemon as specified by the Mod-
           ifier=  part  of  DaemonPortOptions  whereby  the
           flags  are  separated  from each other by spaces,
           and upper case flags are doubled.  That is, Modi-
           fier=Ea  will  be represented as "EE a" in ${dae-
           mon_flags}, which is  required  for  testing  the
           flags in rulesets.

      ${daemon_info}
           Some information about a daemon as a text string.
           For example, "SMTP+queueing@00:30:00".










SMM:08-78          Sendmail Installation and Operation Guide


      ${daemon_name}
           The name of  the  daemon  from  DaemonPortOptions
           Name=  suboption.   If this suboption is not set,
           "Daemon#", where # is the daemon number, is used.

      ${daemon_port}
           The port the daemon is accepting  connection  on.
           Unless  DaemonPortOptions  is set, this will most
           likely be "25".

      ${deliveryMode}
           The current delivery mode sendmail is using.   It
           is initially set to the value of the DeliveryMode
           option.

      ${envid}
           The envelope  id  parameter  (ENVID=)  passed  to
           sendmail as part of the envelope.

      ${hdrlen}
           The length of the header value which is stored in
           ${currHeader} (before possible  truncation).   If
           this  value  is  greater than or equal to MAXNAME
           the header has been truncated.

      ${hdr_name}
           The name of the header field for which  the  cur-
           rent  header check ruleset has been called.  This
           is useful for a default header check  ruleset  to
           get  the  name  of  the header; the macro is only
           available in header check rulesets.

      ${if_addr}
           The IP address of the interface  of  an  incoming
           connection  unless  it  is  in  the loopback net.
           IPv6 addresses are tagged with "IPv6:" before the
           address.

      ${if_addr_out}
           The  IP  address  of the interface of an outgoing
           connection unless it  is  in  the  loopback  net.
           IPv6 addresses are tagged with "IPv6:" before the
           address.

      ${if_family}
           The IP family of the  interface  of  an  incoming
           connection unless it is in the loopback net.

      ${if_family_out}
           The  IP  family  of  the interface of an outgoing
           connection unless it is in the loopback net.












Sendmail Installation and Operation Guide          SMM:08-79


      ${if_name}
           The hostname associated with the interface of  an
           incoming  connection.  This macro can be used for
           SmtpGreetingMessage  and  HReceived  for  virtual
           hosting.  For example:

               O SmtpGreetingMessage=$?{if_name}${if_name}$|$j$. MTA


      ${if_name_out}
           The  name of the interface of an outgoing connec-
           tion.

      ${load_avg}
           The current load average.

      ${mail_addr}
           The address part of the resolved  triple  of  the
           address given for the SMTP MAIL command.  Defined
           in the SMTP server only.

      ${mail_host}
           The host from the resolved triple of the  address
           given  for the SMTP MAIL command.  Defined in the
           SMTP server only.

      ${mail_mailer}
           The  mailer  from  the  resolved  triple  of  the
           address given for the SMTP MAIL command.  Defined
           in the SMTP server only.

      ${msg_id}
           The value of the Message-Id: header.

      ${msg_size}
           The value of the SIZE= parameter,  i.e.,  usually
           the  size  of the message (in an ESMTP dialogue),
           before the message has been collected, thereafter
           the message size as computed by sendmail (and can
           be used in check_compat).

      ${nbadrcpts}
           The number of bad recipients for  a  single  mes-
           sage.

      ${nrcpts}
           The  number  of validated recipients for a single
           message.  Note: since recipient  validation  hap-
           pens  after check_rcpt has been called, the value
           in this ruleset is one less than  what  might  be
           expected.












SMM:08-80          Sendmail Installation and Operation Guide


      ${ntries}
           The number of delivery attempts.

      ${opMode}
           The current operation mode (from the -b flag).

      ${quarantine}
           The  quarantine reason for the envelope, if it is
           quarantined.

      ${queue_interval}
           The queue run interval given by the -q flag.  For
           example,  -q30m  would  set  ${queue_interval} to
           "00:30:00".

      ${rcpt_addr}
           The address part of the resolved  triple  of  the
           address given for the SMTP RCPT command.  Defined
           in the SMTP server only after a RCPT command.

      ${rcpt_host}
           The host from the resolved triple of the  address
           given  for the SMTP RCPT command.  Defined in the
           SMTP server only after a RCPT command.

      ${rcpt_mailer}
           The  mailer  from  the  resolved  triple  of  the
           address given for the SMTP RCPT command.  Defined
           in the SMTP server only after a RCPT command.

      ${server_addr}
           The address of the server of the current outgoing
           SMTP  connection.  For LMTP delivery the macro is
           set to the name of the mailer.

      ${server_name}
           The name of the server of  the  current  outgoing
           SMTP or LMTP connection.

      ${time}
           The  output  of  the  time(3) function, i.e., the
           number of seconds since 0  hours,  0  minutes,  0
           seconds,  January  1, 1970, Coordinated Universal
           Time (UTC).

      ${tls_version}
           The TLS/SSL  version  used  for  the  connection,
           e.g., TLSv1, SSLv3, SSLv2; defined after STARTTLS
           has been used.

      ${total_rate}
           The total number of incoming connections over the
           time         interval         specified        by










Sendmail Installation and Operation Guide          SMM:08-81


           ConnectionRateWindowSize.

      ${verify}
           The result of the verification of  the  presented
           cert;  only  defined after STARTTLS has been used
           (or attempted).  Possible values are:

               OK           verification succeeded.
               NO           no cert presented.
               NOT          no cert requested.
               FAIL         cert presented but could not be verified,
                            e.g., the signing CA is missing.
               NONE         STARTTLS has not been performed.
               TEMP         temporary error occurred.
               PROTOCOL     some protocol error occurred
                            at the ESMTP level (not TLS).
               SOFTWARE     STARTTLS handshake failed,
                            which is a fatal error for this session,
                            the e-mail will be queued.


           There are three types of dates that can be  used.
      The  $a and $b macros are in RFC 822 format; $a is the
      time as extracted from the "Date:" line of the message
      (if  there  was  one),  and $b is the current date and
      time (used for postmarks).   If  no  "Date:"  line  is
      found  in  the incoming message, $a is set to the cur-
      rent time also.  The $d macro is equivalent to the  $b
      macro in UNIX (ctime) format.

           The macros $w, $j, and $m are set to the identity
      of this host.  Sendmail tries to find the fully quali-
      fied name of the host if at all possible; it does this
      by calling gethostname(2) to get the current  hostname
      and  then  passing  that  to gethostbyname(3) which is
      supposed to return the canonical version of that  host
      name.[17]  Assuming  this  is successful, $j is set to
      the fully qualified name and $m is set to  the  domain
      part  of  the  name  (everything after the first dot).
      The $w macro is set  to  the  first  word  (everything
      before  the first dot) if you have a level 5 or higher
      configuration file; otherwise, it is set to  the  same
      value as $j.  If the canonification is not successful,
      it is imperative that the config file set  $j  to  the
      fully qualified domain name[18].
____________________
   [17]For example, on some systems gethostname might return
"foo" which would be mapped to "foo.bar.com"  by  gethostby-
name.
   [18]Older  versions  of  sendmail didn't pre-define $j at
all, so up until 8.6, config files always had to define $j.












SMM:08-82          Sendmail Installation and Operation Guide


           The $f macro is the id of the  sender  as  origi-
      nally  determined; when mailing to a specific host the
      $g macro is set to the address of the sender  relative
      to  the  recipient.   For  example, if I send to "bol-
      lard@matisse.CS.Berkeley.EDU" from the  machine  "van-
      gogh.CS.Berkeley.EDU"  the $f macro will be "eric" and
      the $g macro will be "eric@vangogh.CS.Berkeley.EDU."

           The $x macro is set  to  the  full  name  of  the
      sender.   This  can be determined in several ways.  It
      can be passed as flag to sendmail.  It can be  defined
      in the NAME environment variable.  The third choice is
      the value of the "Full-Name:" line in the header if it
      exists,  and the fourth choice is the comment field of
      a "From:" line.  If all of these fail, and if the mes-
      sage  is  being  originated  locally, the full name is
      looked up in the /etc/passwd file.

           When sending, the $h, $u, and $z macros  get  set
      to  the  host,  user, and home directory (if local) of
      the recipient.  The first two are set from the $@  and
      $: part of the rewriting rules, respectively.

           The  $p  and  $t macros are used to create unique
      strings (e.g., for the "Message-Id:" field).   The  $i
      macro is set to the queue id on this host; if put into
      the timestamp line it  can  be  extremely  useful  for
      tracking messages.  The $v macro is set to be the ver-
      sion number of sendmail; this is normally put in time-
      stamps and has been proven extremely useful for debug-
      ging.

           The $c field is set to the "hop count," i.e., the
      number of times this message has been processed.  This
      can be determined by the -h flag on the  command  line
      or by counting the timestamps in the message.

           The $r and $s fields are set to the protocol used
      to communicate with sendmail and the sending hostname.
      They  can  be  set  together using the -p command line
      flag or separately using the -M or -oM flags.

           The $_ is set to a validated  sender  host  name.
      If  the  sender is running an RFC 1413 compliant IDENT
      server and the receiver has the IDENT protocol  turned
      on, it will include the user name on that host.

           The     ${client_name},    ${client_addr},    and
      ${client_port} macros are set to  the  name,  address,
      and  port  number  of  the SMTP client who is invoking
      sendmail as a  server.   These  can  be  used  in  the
      check_*  rulesets  (using  the  $& deferred evaluation
      form, of course!).










Sendmail Installation and Operation Guide          SMM:08-83


   5.3.  C and F -- Define Classes

           Classes of phrases may be defined to match on the
      left hand side of rewriting rules, where a "phrase" is
      a sequence of characters that does not  contain  space
      characters.   For  example  a class of all local names
      for this site might be created  so  that  attempts  to
      send  to  oneself can be eliminated.  These can either
      be defined directly in the configuration file or  read
      in  from  another file.  Classes are named as a single
      letter or a word in {braces}.  Class  names  beginning
      with  lower  case  letters  and special characters are
      reserved for system use.  Classes  defined  in  config
      files  may  be  given names from the set of upper case
      letters for short names or  beginning  with  an  upper
      case letter for long names.

           The syntax is:

          Ccphrase1 phrase2...
          Fcfile
          Fc|program
          Fc[mapkey]@mapclass:mapspec

      The first form defines the class c to match any of the
      named words.  If phrase1 or phrase2 is another  class,
      e.g.,  $=S, the contents of class S are added to class
      c.  It is permissible to  split  them  among  multiple
      lines; for example, the two forms:

          CHmonet ucbmonet

      and

          CHmonet
          CHucbmonet

      are  equivalent.  The ``F'' forms read the elements of
      the class c from the named file, program, or map spec-
      ification.   Each  element should be listed on a sepa-
      rate line.  To specify an optional  file,  use  ``-o''
      between the class name and the file name, e.g.,

          Fc -o /path/to/file

      If  the file can't be used, sendmail will not complain
      but silently ignore it.  The map  form  should  be  an
      optional map key, an at sign, and a map class followed
      by the specification for that map.  Examples include:

          F{VirtHosts}@ldap:-k (&(objectClass=virtHosts)(host=*)) -v host
          F{MyClass}foo@hash:/etc/mail/classes











SMM:08-84          Sendmail Installation and Operation Guide


      will fill the class $={VirtHosts}  from  an  LDAP  map
      lookup and $={MyClass} from a hash database map lookup
      of the foo.  There is also a built-in schema that  can
      be accessed by only specifying:

          F{ClassName}@LDAP

      This will tell sendmail to use the default schema:

          -k (&(objectClass=sendmailMTAClass)
               (sendmailMTAClassName=ClassName)
               (|(sendmailMTACluster=${sendmailMTACluster})
                 (sendmailMTAHost=$j)))
          -v sendmailMTAClassValue

      Note  that  the  lookup  is only done when sendmail is
      initially started.

           Elements of classes  can  be  accessed  in  rules
      using  $=  or $~.  The $~ (match entries not in class)
      only matches a single word; multi-word entries in  the
      class are ignored in this context.

           Some classes have internal meaning to sendmail:

      $=e  contains  the Content-Transfer-Encodings that can
           be 8->7 bit encoded.  It is predefined to contain
           "7bit", "8bit", and "binary".

      $=k  set  to be the same as $k, that is, the UUCP node
           name.

      $=m  set to the set of domains by which this  host  is
           known, initially just $m.

      $=n  can be set to the set of MIME body types that can
           never be eight to seven bit encoded.  It defaults
           to "multipart/signed".  Message types "message/*"
           and "multipart/*"  are  never  encoded  directly.
           Multipart  messages  are  always  handled  recur-
           sively.  The handling of message/*  messages  are
           controlled by class $=s.

      $=q  A set of Content-Types that will never be encoded
           as base64 (if they have to be encoded, they  will
           be  encoded  as  quoted-printable).   It can have
           primary types (e.g., "text") or full types  (such
           as "text/plain").

      $=s  contains  the set of subtypes of message that can
           be treated recursively.  By default  it  contains
           only "rfc822".  Other "message/*" types cannot be
           8->7 bit encoded.  If a message containing  eight










Sendmail Installation and Operation Guide          SMM:08-85


           bit  data  is  sent to a seven bit host, and that
           message cannot be encoded  into  seven  bits,  it
           will be stripped to 7 bits.

      $=t  set to the set of trusted users by the T configu-
           ration line.  If you want to read  trusted  users
           from a file, use Ft/file/name.

      $=w  set to be the set of all names this host is known
           by.  This can be used to match local hostnames.

      $={persistentMacros}
           set to the macros that  should  be  saved  across
           queue  runs.   Care  should  be taken when adding
           macro names to this class.

           Sendmail can be  compiled  to  allow  a  scanf(3)
      string  on  the  F  line.  This lets you do simplistic
      parsing of text files.  For example, to read  all  the
      user  names  in  your  system  /etc/passwd file into a
      class, use

          FL/etc/passwd %[^:]

      which reads every line up to the first colon.

   5.4.  M -- Define Mailer

           Programs and interfaces to mailers are defined in
      this line.  The format is:

          Mname, {field=value}*

      where  name is the name of the mailer (used internally
      only) and the "field=name" pairs define attributes  of
      the mailer.  Fields are:



























SMM:08-86          Sendmail Installation and Operation Guide


          Path      The pathname of the mailer
          Flags     Special flags for this mailer
          Sender    Rewriting set(s) for sender addresses
          Recipient Rewriting set(s) for recipient addresses
          recipientsMaximum number of recipients per connection
          Argv      An argument vector to pass to this mailer
          Eol       The end-of-line string for this mailer
          Maxsize   The maximum message length to this mailer
          maxmessagesThe maximum message deliveries per connection
          Linelimit The maximum line length in the message body
          Directory The working directory for the mailer
          Userid    The default user and group id to run as
          Nice      The nice(2) increment for the mailer
          Charset   The default character set for 8-bit characters
          Type      Type information for DSN diagnostics
          Wait      The maximum time to wait for the mailer
          QueuegroupThe default queue group for the mailer
          /         The root directory for the mailer

      Only  the first character of the field name is checked
      (it's case-sensitive).

           The following flags may  be  set  in  the  mailer
      description.   Any  other  flags may be used freely to
      conditionally assign headers to messages destined  for
      particular  mailers.   Flags  marked  with  *  are not
      interpreted by the sendmail binary; these are the con-
      ventionally  used to correlate to the flags portion of
      the H line.  Flags marked with # apply to the  mailers
      for the sender address rather than the usual recipient
      mailers.

      a   Run Extended SMTP  (ESMTP)  protocol  (defined  in
          RFCs 1869, 1652, and 1870).  This flag defaults on
          if the SMTP greeting  message  includes  the  word
          "ESMTP".

      A   Look  up  the  user (address) part of the resolved
          mailer triple, in the  alias  database.   Normally
          this is only set for local mailers.

      b   Force  a blank line on the end of a message.  This
          is intended to work around some stupid versions of
          /bin/mail  that  require  a blank line, but do not
          provide it themselves.  It would not  normally  be
          used on network mail.

      B   Strip  leading backslashes (\) off of the address;
          this is a subset of the  functionality  of  the  s
          flag.

      c   Do not include comments in addresses.  This should
          only be used if you have to work around  a  remote










Sendmail Installation and Operation Guide          SMM:08-87


          mailer  that  gets  confused  by  comments.   This
          strips addresses of the form "Phrase <address>" or
          "address (Comment)" down to just "address".

      C#  If  mail  is received from a mailer with this flag
          set, any addresses in the header that do not  have
          an  at sign ("@") after being rewritten by ruleset
          three will have  the  "@domain"  clause  from  the
          sender  envelope  address  tacked on.  This allows
          mail with headers of the form:

              From: usera@hosta
              To: userb@hostb, userc

          to be rewritten as:

              From: usera@hosta
              To: userb@hostb, userc@hosta

          automatically.  However, it  doesn't  really  work
          reliably.

      d   Do not include angle brackets around route-address
          syntax addresses.  This is useful on mailers  that
          are  going to pass addresses to a shell that might
          interpret angle brackets as I/O redirection.  How-
          ever,  it  does  not  protect  against other shell
          metacharacters.  Therefore, passing addresses to a
          shell should not be considered secure.

      D*  This mailer wants a "Date:" header line.

      e   This  mailer is expensive to connect to, so try to
          avoid connecting normally; any  necessary  connec-
          tion  will  occur  during  a  queue run.  See also
          option HoldExpensive.

      E   Escape lines beginning with "From " in the message
          with a `>' sign.

      f   The  mailer wants a -f from flag, but only if this
          is a network forward operation (i.e.,  the  mailer
          will  give an error if the executing user does not
          have special permissions).

      F*  This mailer wants a "From:" header line.

      g   Normally,  sendmail  sends  internally   generated
          email (e.g., error messages) using the null return
          address as required by RFC  1123.   However,  some
          mailers  don't  accept  a null return address.  If
          necessary, you can set the g flag to prevent send-
          mail  from  obeying  the standards; error messages










SMM:08-88          Sendmail Installation and Operation Guide


          will be sent as from the MAILER-DAEMON  (actually,
          the value of the $n macro).

      h   Upper  case should be preserved in host names (the
          $@ portion of the  mailer  triplet  resolved  from
          ruleset 0) for this mailer.

      i   Do  User  Database  rewriting  on  envelope sender
          address.

      I   This mailer will be speaking SMTP to another send-
          mail  --  as such it can use special protocol fea-
          tures.  This flag should not be  used  except  for
          debugging  purposes  because  it uses VERB as SMTP
          command.

      j   Do User Database rewriting on recipients  as  well
          as senders.

      k   Normally  when  sendmail  connects  to  a host via
          SMTP, it checks to make sure that this isn't acci-
          dently the same host name as might happen if send-
          mail is misconfigured or if  a  long-haul  network
          interface is set in loopback mode.  This flag dis-
          ables the loopback check.  It should only be  used
          under very unusual circumstances.

      K   Currently unimplemented.  Reserved for chunking.

      l   This mailer is local (i.e., final delivery will be
          performed).

      L   Limit the line lengths as specified  in  RFC  821.
          This  deprecated  option should be replaced by the
          L= mail declaration.  For historic reasons, the  L
          flag also sets the 7 flag.

      m   This mailer can send to multiple users on the same
          host in one transaction.  When a $u  macro  occurs
          in  the  argv  part of the mailer definition, that
          field will be repeated as necessary for all quali-
          fying users.  Removing this flag can defeat dupli-
          cate supression on a remote site as each recipient
          is sent in a separate transaction.

      M*  This mailer wants a "Message-Id:" header line.

      n   Do  not  insert  a  UNIX-style  "From" line on the
          front of the message.

      o   Always run as the owner of the recipient  mailbox.
          Normally  sendmail  runs as the sender for locally
          generated mail or as "daemon" (actually, the  user










Sendmail Installation and Operation Guide          SMM:08-89


          specified in the u option) when delivering network
          mail.  The normal behavior  is  required  by  most
          local  mailers,  which will not allow the envelope
          sender address to be set unless the mailer is run-
          ning  as  daemon.   This  flag is ignored if the S
          flag is set.

      p   Use the route-addr style reverse-path in the  SMTP
          "MAIL  FROM:"  command rather than just the return
          address; although this is required in RFC 821 sec-
          tion  3.1, many hosts do not process reverse-paths
          properly.  Reverse-paths are  officially  discour-
          aged by RFC 1123.

      P*  This mailer wants a "Return-Path:" line.

      q   When  an  address  that resolves to this mailer is
          verified  (SMTP  VRFY   command),   generate   250
          responses  instead  of  252  responses.  This will
          imply that the address is local.

      r   Same as f, but sends a -r flag.

      R   Open  SMTP  connections  from  a  "secure"   port.
          Secure  ports  aren't  (secure, that is) except on
          UNIX machines, so it is  unclear  that  this  adds
          anything.   sendmail must be running as root to be
          able to use this flag.

      s   Strip quote  characters  ("  and  \)  off  of  the
          address before calling the mailer.

      S   Don't  reset the userid before calling the mailer.
          This would be used in a secure  environment  where
          sendmail ran as root.  This could be used to avoid
          forged addresses.  If the U= field is also  speci-
          fied, this flag causes the effective user id to be
          set to that user.

      u   Upper case should be preserved in user  names  for
          this  mailer.   Standards  require preservation of
          case in the local part of  addresses,  except  for
          those   address  for  which  your  system  accepts
          responsibility.  RFC 2142 provides a long list  of
          addresses  which  should  be case insensitive.  If
          you use this flag, you may be violating RFC  2142.
          Note  that  postmaster is always treated as a case
          insensitive address regardless of this flag.

      U   This mailer wants UUCP-style "From" lines with the
          ugly "remote from <host>" on the end.












SMM:08-90          Sendmail Installation and Operation Guide


      w   The  user  must  have  a  valid  account  on  this
          machine, i.e., getpwnam must succeed.  If not, the
          mail  is  bounced.   See  also the MailBoxDatabase
          option.  This is required to get ".forward"  capa-
          bility.

      W   Ignore long term host status information (see Sec-
          tion "Persistent Host Status Information").

      x*  This mailer wants a "Full-Name:" header line.

      X   This mailer wants to use the hidden dot  algorithm
          as  specified  in  RFC  821;  basically,  any line
          beginning with  a  dot  will  have  an  extra  dot
          prepended (to be stripped at the other end).  This
          insures that lines in the message containing a dot
          will not terminate the message prematurely.

      z   Run  Local  Mail  Transfer Protocol (LMTP) between
          sendmail and the local mailer.  This is a  variant
          on  SMTP  defined in RFC 2033 that is specifically
          designed for delivery to a local mailbox.

      Z   Apply DialDelay (if set) to this mailer.

      0   Don't look  up  MX  records  for  hosts  sent  via
          SMTP/LMTP.  Do not apply FallbackMXhost either.

      1   Don't send null characters ('\0') to this mailer.

      2   Don't  use  ESMTP  even if offered; this is useful
          for broken systems that offer ESMTP  but  fail  on
          EHLO (without recovering when HELO is tried next).

      3   Extend  the  list  of  characters converted to =XX
          notation when converting  to  Quoted-Printable  to
          include those that don't map cleanly between ASCII
          and EBCDIC.  Useful if you have IBM mainframes  on
          site.

      5   If no aliases are found for this address, pass the
          address through ruleset 5 for  possible  alternate
          resolution.   This is intended to forward the mail
          to an alternate delivery spot.

      6   Strip headers to seven bits.

      7   Strip all output  to  seven  bits.   This  is  the
          default  if the L flag is set.  Note that clearing
          this option is not sufficient to  get  full  eight
          bit data passed through sendmail.  If the 7 option
          is set, this is essentially always set, since  the
          eighth  bit was stripped on input.  Note that this










Sendmail Installation and Operation Guide          SMM:08-91


          option will only impact messages that didn't  have
          8->7 bit MIME conversions performed.

      8   If set, it is acceptable to send eight bit data to
          this mailer; the usual attempt to do 8->7 bit MIME
          conversions will be bypassed.

      9   If  set,  do  limited  7->8  bit MIME conversions.
          These conversions are limited to text/plain data.

      :   Check addresses to see if they begin  ":include:";
          if  they  do,  convert  them  to  the  "*include*"
          mailer.

      |   Check addresses to see if they begin with  a  `|';
          if they do, convert them to the "prog" mailer.

      /   Check  addresses  to see if they begin with a `/';
          if they do, convert them to the "*file*" mailer.

      @   Look up addresses in the user database.

      %   Do not attempt delivery on initial  receipt  of  a
          message or on queue runs unless the queued message
          is selected using one of the -qI/-qR/-qS queue run
          modifiers or an ETRN request.

           Configuration  files  prior to level 6 assume the
      `A', `w', `5', `:', `|', `/', and `@' options  on  the
      mailer named "local".

           The  mailer  with the special name "error" can be
      used to generate a user error.   The  (optional)  host
      field  is  an exit status to be returned, and the user
      field is a message to be printed.  The exit status may
      be numeric or one of the values USAGE, NOUSER, NOHOST,
      UNAVAILABLE, SOFTWARE, TEMPFAIL, PROTOCOL,  or  CONFIG
      to  return  the  corresponding  EX_  exit  code, or an
      enhanced error code as described in RFC 1893, Enhanced
      Mail System Status Codes.  For example, the entry:

          $#error $@ NOHOST $: Host unknown in this domain

      on the RHS of a rule will cause the specified error to
      be generated and the "Host unknown" exit status to  be
      returned  if  the  LHS  matches.   This mailer is only
      functional in rulesets 0, 5, or  one  of  the  check_*
      rulesets.  The host field can also contain the special
      token quarantine which instructs sendmail  to  quaran-
      tine the current message.

           The mailer with the special name "discard" causes
      any mail sent to it  to  be  discarded  but  otherwise










SMM:08-92          Sendmail Installation and Operation Guide


      treated  as  though  it  were  successfully delivered.
      This mailer cannot be used in ruleset 0, only  in  the
      various address checking rulesets.

           The mailer named "local" must be defined in every
      configuration file.  This is  used  to  deliver  local
      mail, and is treated specially in several ways.  Addi-
      tionally, three other mailers named "prog",  "*file*",
      and "*include*" may be defined to tune the delivery of
      messages  to  programs,  files,  and  :include:  lists
      respectively.  They default to:

          Mprog, P=/bin/sh, F=lsoDq9, T=DNS/RFC822/X-Unix, A=sh -c $u
          M*file*, P=[FILE], F=lsDFMPEouq9, T=DNS/RFC822/X-Unix, A=FILE $u
          M*include*, P=/dev/null, F=su, A=INCLUDE $u


           Builtin  pathnames are [FILE] and [IPC], the for-
      mer is used for delivery  to  files,  the  latter  for
      delivery  via interprocess communication.  For mailers
      that use [IPC] as pathname the  argument  vector  (A=)
      must  start with TCP or FILE for delivery via a TCP or
      a Unix domain socket.  If  TCP  is  used,  the  second
      argument  must  be  the  name  of the host to contact.
      Optionally a third argument can be used to  specify  a
      port, the default is smtp (port 25).  If FILE is used,
      the second argument must  be  the  name  of  the  Unix
      domain socket.

           If  the  argument vector does not contain $u then
      sendmail will speak SMTP (or LMTP if the mailer flag z
      is specified) to the mailer.

           If  no  Eol field is defined, then the default is
      "\r\n" for SMTP mailers and "\n" of others.

           The  Sender  and  Recipient  rewriting  sets  may
      either  be a simple ruleset id or may be two ids sepa-
      rated by a slash; if so, the first  rewriting  set  is
      applied  to  envelope  addresses  and  the  second  is
      applied to headers.  Setting any value  to  zero  dis-
      ables corresponding mailer-specific rewriting.

           The  Directory is actually a colon-separated path
      of directories to try.  For  example,  the  definition
      "D=$z:/"  first  tries  to  execute in the recipient's
      home directory; if that is not available, it tries  to
      execute  in  the  root  of  the  filesystem.   This is
      intended to be used only on the "prog"  mailer,  since
      some  shells  (such  as csh) refuse to execute if they
      cannot read the current directory.   Since  the  queue
      directory  is  not  normally  readable by unprivileged
      users csh scripts as recipients can fail.










Sendmail Installation and Operation Guide          SMM:08-93


           The Userid specifies the default user  and  group
      id  to  run  as,  overriding  the  DefaultUser  option
      (q.v.).  If the S mailer flag is also specified,  this
      user  and  group  will be set as the effective uid and
      gid for the process.  This may be given as  user:group
      to  set  both  the user and group id; either may be an
      integer or a symbolic name to  be  looked  up  in  the
      passwd  and  group files respectively.  If only a sym-
      bolic user name is specified,  the  group  id  in  the
      passwd file for that user is used as the group id.

           The  Charset field is used when converting a mes-
      sage to MIME; this is the character set  used  in  the
      Content-Type:   header.   If  this  is  not  set,  the
      DefaultCharset option is used, and if that is not set,
      the value "unknown-8bit" is used.  WARNING: this field
      applies to the sender's mailer,  not  the  recipient's
      mailer.   For  example, if the envelope sender address
      lists an address on the local network and the  recipi-
      ent  is on an external network, the character set will
      be set from the Charset= field for the  local  network
      mailer, not that of the external network mailer.

           The Type= field sets the type information used in
      MIME error messages as defined by  RFC  1894.   It  is
      actually  three  values separated by slashes: the MTA-
      type (that  is,  the  description  of  how  hosts  are
      named),  the  address  type (the description of e-mail
      addresses), and the diagnostic type  (the  description
      of  error  diagnostic codes).  Each of these must be a
      registered value or begin with "X-".  The  default  is
      "dns/rfc822/smtp".

           The m= field specifies the maximum number of mes-
      sages to attempt to deliver on a single SMTP  or  LMTP
      connection.  The default is infinite.

           The  r=  field  specifies  the  maximum number of
      recipients to attempt to deliver in a single envelope.
      It defaults to 100.

           The  /=  field specifies a new root directory for
      the mailer.  The  path  is  macro  expanded  and  then
      passed  to  the "chroot" system call.  The root direc-
      tory is changed before the  Directory  field  is  con-
      sulted or the uid is changed.

           The  Wait=  field  specifies  the maximum time to
      wait for the mailer to return after sending  all  data
      to  it.  This applies to mailers that have been forked
      by sendmail.












SMM:08-94          Sendmail Installation and Operation Guide


           The Queuegroup= field specifies the default queue
      group  in  which received mail should be queued.  This
      can be overridden by other means as explained in  sec-
      tion ``Queue Groups and Queue Directories''.

   5.5.  H -- Define Header

           The  format  of  the  header  lines that sendmail
      inserts into the message are defined by  the  H  line.
      The syntax of this line is one of the following:

          Hhname: htemplate


          H[?mflags?]hname: htemplate


          H[?${macro}?]hname: htemplate

      Continuation lines in this spec are reflected directly
      into the outgoing message.  The  htemplate  is  macro-
      expanded  before  insertion  into the message.  If the
      mflags (surrounded by question marks)  are  specified,
      at  least one of the specified flags must be stated in
      the mailer definition for this header to be  automati-
      cally  output.   If a ${macro} (surrounded by question
      marks) is specified, the header will be  automatically
      output  if  the  macro  is  set.  The macro may be set
      using any of the normal methods, including  using  the
      macro storage map in a ruleset.  If one of these head-
      ers is in the input it  is  reflected  to  the  output
      regardless  of  these  flags  or macros.  Notice: If a
      ${macro} is used to set a header, then it is useful to
      add  that  macro  to  class $={persistentMacros} which
      consists of the macros that  should  be  saved  across
      queue runs.

           Some  headers have special semantics that will be
      described later.

           A secondary syntax allows validation  of  headers
      as they are being read.  To enable validation, use:

          HHeader: $>Ruleset
          HHeader: $>+Ruleset

      The  indicated  Ruleset  is  called  for the specified
      Header, and can return $#error to reject or quarantine
      the  message  or  $#discard to discard the message (as
      with  the  other  check_*  rulesets).    The   ruleset
      receives  the header field-body as argument, i.e., not
      the header field-name; see also ${hdr_name} and ${cur-
      rHeader}.   The  header  is  treated  as  a structured










Sendmail Installation and Operation Guide          SMM:08-95


      field, that is, text in parentheses is deleted  before
      processing, unless the second form $>+ is used.  Note:
      only one ruleset can  be  associated  with  a  header;
      sendmail will silently ignore multiple entries.

           For example, the configuration lines:

          HMessage-Id: $>CheckMessageId

          SCheckMessageId
          R< $+ @ $+  >$@ OK
          R$*       $#error $: Illegal Message-Id header

      would refuse any message that had a Message-Id: header
      of any of the following forms:

          Message-Id: <>
          Message-Id: some text
          Message-Id: <legal text@domain> extra crud

      A default ruleset that is  called  for  headers  which
      don't  have a specific ruleset defined for them can be
      specified by:

          H*: $>Ruleset

      or

          H*: $>+Ruleset


   5.6.  O -- Set Option

           There are a number of global options that can  be
      set  from  a  configuration  file.  Options are repre-
      sented by full words; some are also  representable  as
      single  characters for back compatibility.  The syntax
      of this line is:

          O  option=value

      This sets option option to be value.  Note that  there
      must be a space between the letter `O' and the name of
      the option.  An older version is:

          Oovalue

      where the option o is a single  character.   Depending
      on  the  option,  value may be a string, an integer, a
      boolean (with legal values "t", "T", "f", or "F";  the
      default is TRUE), or a time interval.












SMM:08-96          Sendmail Installation and Operation Guide


           All  filenames used in options should be absolute
      paths, i.e., starting with  '/'.   Relative  filenames
      most  likely  cause surprises during operation (unless
      otherwise noted).

           The options supported (with the old, one  charac-
      ter names in brackets) are:

      AliasFile=spec, spec, ...
                [A]  Specify  possible  alias file(s).  Each
                spec should be in the format ``class: info''
                where  class:  is  optional  and defaults to
                ``implicit''.  Note that  info  is  required
                for  all  classes  except  "ldap".   For the
                "ldap" class, if info is  not  specified,  a
                default info value is used as follows:

                    -k (&(objectClass=sendmailMTAAliasObject)
                         (sendmailMTAAliasName=aliases)
                         (|(sendmailMTACluster=${sendmailMTACluster})
                           (sendmailMTAHost=$j))
                         (sendmailMTAKey=%0))
                    -v sendmailMTAAliasValue

                Depending on how sendmail is compiled, valid
                classes are  "implicit"  (search  through  a
                compiled-in  list  of  alias file types, for
                back compatibility),  "hash"  (if  NEWDB  is
                specified), "btree" (if NEWDB is specified),
                "dbm" (if NDBM is specified), "stab" (inter-
                nal symbol table -- not normally used unless
                you  have   no   other   database   lookup),
                "sequence"  (use  a  sequence of maps previ-
                ously declared), "ldap" (if LDAPMAP is spec-
                ified),  or "nis" (if NIS is specified).  If
                a  list  of  specs  are  provided,  sendmail
                searches them in order.

      AliasWait=timeout
                [a]  If  set,  wait  up  to  timeout  (units
                default to minutes) for an  "@:@"  entry  to
                exist  in the alias database before starting
                up.  If it does not appear  in  the  timeout
                interval issue a warning.

      AllowBogusHELO
                [no short name] If set, allow HELO SMTP com-
                mands that don't include a host name.   Set-
                ting  this  violates RFC 1123 section 5.2.5,
                but is necessary to interoperate  with  sev-
                eral  SMTP clients.  If there is a value, it
                is still checked for legitimacy.











Sendmail Installation and Operation Guide          SMM:08-97


      AuthMaxBits=N
                [no short name] Limit the maximum encryption
                strength for the security layer in SMTP AUTH
                (SASL). Default  is  essentially  unlimited.
                This  allows  to turn off additional encryp-
                tion in SASL if STARTTLS is already encrypt-
                ing  the communication, because the existing
                encryption strength is  taken  into  account
                when  choosing an algorithm for the security
                layer.  For example, if STARTTLS is used and
                the  symmetric  cipher is 3DES, then the the
                keylength (in bits) is 168.   Hence  setting
                AuthMaxBits  to 168 will disable any encryp-
                tion in SASL.

      AuthMechanisms
                [no short name] List of authentication mech-
                anisms  for AUTH (separated by spaces).  The
                advertised list of authentication mechanisms
                will  be  the  intersection of this list and
                the list of available mechanisms  as  deter-
                mined  by the Cyrus SASL library.  If START-
                TLS is active, EXTERNAL  will  be  added  to
                this  list.   In  that  case,  the  value of
                {cert_subject} is used as authentication id.

      AuthOptions
                [no short name] List  of  options  for  SMTP
                AUTH  consisting  of  single characters with
                intervening white space or commas.

                    A   Use the AUTH= parameter for the MAIL FROM
                        command only when authentication succeeded.
                        This can be used as a workaround for broken
                        MTAs that do not implement RFC 2554 correctly.
                    a   protection from active (non-dictionary) attacks
                        during authentication exchange.
                    c   require mechanisms which pass client credentials,
                        and allow mechanisms which can pass credentials
                        to do so.
                    d   don't permit mechanisms susceptible to passive
                        dictionary attack.
                    f   require forward secrecy between sessions
                        (breaking one won't help break next).
                    m   require mechanisms which provide mutual authentication
                        (only available if using Cyrus SASL v2 or later).
                    p   don't permit mechanisms susceptible to simple
                        passive attack (e.g., PLAIN, LOGIN), unless a
                        security layer is active.
                    y   don't permit mechanisms that allow anonymous login.

                The first option applies to  sendmail  as  a
                client, the others to a server.  Example:










SMM:08-98          Sendmail Installation and Operation Guide


                    O AuthOptions=p,y

                would  disallow  ANONYMOUS as AUTH mechanism
                and would allow PLAIN and LOGIN  only  if  a
                security  layer (e.g., provided by STARTTLS)
                is already active.  The  options  'a',  'c',
                'd',  'f',  'p', and 'y' refer to properties
                of the selected SASL  mechanisms.   Explana-
                tions  of  these  properties can be found in
                the Cyrus SASL documentation.

      AuthRealm [no short  name]  The  authentication  realm
                that  is  passed  to the Cyrus SASL library.
                If no realm is specified, $j is used.

      BadRcptThrottle=N
                [no short name] If  set  and  the  specified
                number of recipients in a single SMTP trans-
                action have been  rejected,  sleep  for  one
                second after each subsequent RCPT command in
                that transaction.

      BlankSub=c
                [B] Set the blank substitution character  to
                c.    Unquoted   spaces   in  addresses  are
                replaced by  this  character.   Defaults  to
                space (i.e., no change is made).

      CACertPath
                [no  short name] Path to directory with cer-
                tificates of CAs.  This directory  directory
                must  contain the hashes of each CA certifi-
                cate as filenames (or as links to them).

      CACertFile
                [no short name] File containing one or  more
                CA  certificates; see section about STARTTLS
                for more information.

      CheckAliases
                [n]  Validate  the  RHS  of   aliases   when
                rebuilding the alias database.

      CheckpointInterval=N
                [C]  Checkpoints  the queue every N (default
                10) addresses sent.  If your system  crashes
                during  delivery  to a large list, this pre-
                vents retransmission to any but the  last  N
                recipients.

      ClassFactor=fact
                [z]  The  indicated  factor is multiplied by
                the  message  class   (determined   by   the










Sendmail Installation and Operation Guide          SMM:08-99


                Precedence: field in the user header and the
                P lines in the configuration file) and  sub-
                tracted  from  the priority.  Thus, messages
                with a higher  Priority:  will  be  favored.
                Defaults to 1800.

      ClientCertFile
                [no short name] File containing the certifi-
                cate of the client, i.e.,  this  certificate
                is  used  when  sendmail acts as client (for
                STARTTLS).

      ClientKeyFile
                [no short name] File containing the  private
                key belonging to the client certificate (for
                STARTTLS if sendmail runs as client).

      ClientPortOptions=options
                [O] Set client SMTP  options.   The  options
                are  key=value  pairs  separated  by commas.
                Known keys are:

                    Port      Name/number of source port for connection (defaults to any free port)
                    Addr      Address mask (defaults INADDR_ANY)
                    Family    Address family (defaults to INET)
                    SndBufSizeSize of TCP send buffer
                    RcvBufSizeSize of TCP receive buffer
                    Modifier  Options (flags) for the client

                The Address mask may be a numeric address in
                IPv4  dot notation or IPv6 colon notation or
                a network name.  Note that if a network name
                is  specified,  only  the  first  IP address
                returned for it  will  be  used.   This  may
                cause  indeterminate  behavior  for  network
                names that resolve  to  multiple  addresses.
                Therefore, use of an address is recommended.
                Modifier can be the following character:

                    h         use name of interface for HELO command
                    A         don't use AUTH when sending e-mail
                    S         don't use STARTTLS when sending e-mail

                If ``h'' is set, the name  corresponding  to
                the outgoing interface address (whether cho-
                sen via  the  Connection  parameter  or  the
                default)  is used for the HELO/EHLO command.
                However, the name  must  not  start  with  a
                square  bracket and it must contain at least
                one dot.  This is a simple test whether  the
                name  is not an IP address (in square brack-
                ets) but a qualified  hostname.   Note  that
                multiple   ClientPortOptions   settings  are










SMM:08-100         Sendmail Installation and Operation Guide


                allowed in order to give settings  for  each
                protocol  family  (e.g., one for Family=inet
                and one for  Family=inet6).   A  restriction
                placed  on  one family only affects outgoing
                connections on that particular family.

      ColonOkInAddr
                [no short name] If set, colons  are  accept-
                able     in    e-mail    addresses    (e.g.,
                "host:user").  If not set,  colons  indicate
                the  beginning  of a RFC 822 group construct
                ("groupname:  member1,  member2,  ...   mem-
                berN;").   Doubled colons are always accept-
                able ("nodename::user")  and  proper  route-
                addr       nesting       is       understood
                ("<@relay:user@host>").   Furthermore,  this
                option defaults on if the configuration ver-
                sion level is less than 6 (for back compati-
                bility).   However,  it must be off for full
                compatibility with RFC 822.

      ConnectionCacheSize=N
                [k] The maximum number of  open  connections
                that  will be cached at a time.  The default
                is one.  This  delays  closing  the  current
                connection  until  either this invocation of
                sendmail needs to connect to another host or
                it  terminates.  Setting it to zero defaults
                to the old behavior,  that  is,  connections
                are closed immediately.  Since this consumes
                file  descriptors,  the   connection   cache
                should  be kept small: 4 is probably a prac-
                tical maximum.

      ConnectionCacheTimeout=timeout
                [K] The maximum amount of time a cached con-
                nection  will  be  permitted to idle without
                activity.  If this  time  is  exceeded,  the
                connection   is  immediately  closed.   This
                value should be small (on the order  of  ten
                minutes).   Before  sendmail  uses  a cached
                connection, it always sends a  RSET  command
                to  check  the connection; if this fails, it
                reopens the connection.  This keeps your end
                from  failing  if  the  other end times out.
                The point of this option is  to  be  a  good
                network  neighbor  and avoid using up exces-
                sive  resources  on  the  other  end.    The
                default is five minutes.

      ConnectOnlyTo=address
                [no short name] This can be used to override
                the   connection   address   (for    testing










Sendmail Installation and Operation Guide         SMM:08-101


                purposes).

      ConnectionRateThrottle=N
                [no  short name] If set to a positive value,
                allow no more than N incoming connections in
                a  one  second  period  per daemon.  This is
                intended to flatten out peaks and allow  the
                load  average  checking to cut in.  Defaults
                to zero (no limits).

      ConnectionRateWindowSize=N
                [no short name] Define  the  length  of  the
                interval  for  which  the number of incoming
                connections is maintained.  The  default  is
                60 seconds.

      ControlSocketName=name
                [no  short  name] Name of the control socket
                for daemon management.  A  running  sendmail
                daemon  can be controlled through this named
                socket.   Available  commands   are:   help,
                mstat,  restart,  shutdown, and status.  The
                status command returns the current number of
                daemon  children, the maximum number of dae-
                mon  children,  the  free  disk  space   (in
                blocks) of the queue directory, and the load
                average of the machine expressed as an inte-
                ger.   If not set, no control socket will be
                available.  Solaris  and  pre-4.4BSD  kernel
                users should see the note in sendmail/README
                .

      CRLFile=name
                [no short name] Name of file  that  contains
                certificate  revocation  status,  useful for
                X.509v3   authentication.    CRL    checking
                requires  at  least  OpenSSL  version 0.9.7.
                Note: if a CRLFile is specified but the file
                is unusable, STARTTLS is disabled.

      DHParameters
                Possible values are:

                    5         use 512 bit prime
                    1         use 1024 bit prime
                    none      do not use Diffie-Hellman
                    NAME      load prime from file

                This  is only required if a ciphersuite con-
                taining  DSA/DH  is  used.   If   ``5''   is
                selected, then precomputed, fixed primes are
                used.  This is the default  for  the  client
                side.   If  ``1''  is  selected,  then prime










SMM:08-102         Sendmail Installation and Operation Guide


                values are computed during startup.  This is
                the default for the server side.  Note: this
                operation can take a significant  amount  of
                time  on  a  slow machine (several seconds),
                but it is only done  once  at  startup.   If
                ``none''  is selected, then TLS ciphersuites
                containing DSA/DH cannot be used.  If a file
                name is specified (which must be an absolute
                path), then the primes are read from it.

      DaemonPortOptions=options
                [O] Set server SMTP options.  Each  instance
                of  DaemonPortOptions leads to an additional
                incoming socket.  The options are  key=value
                pairs.  Known keys are:

                    Name      User-definable name for the daemon (defaults to "Daemon#")
                    Port      Name/number of listening port (defaults to "smtp")
                    Addr      Address mask (defaults INADDR_ANY)
                    Family    Address family (defaults to INET)
                    InputMailFiltersList of input mail filters for the daemon
                    Listen    Size of listen queue (defaults to 10)
                    Modifier  Options (flags) for the daemon
                    SndBufSizeSize of TCP send buffer
                    RcvBufSizeSize of TCP receive buffer
                    children  maximum number of children per daemon, see MaxDaemonChildren.
                    DeliveryModeDelivery mode per daemon, see DeliveryMode.
                    refuseLA  RefuseLA per daemon
                    delayLA   DelayLA per daemon
                    queueLA   QueueLA per daemon

                The  Name key is used for error messages and
                logging.  The Address mask may be a  numeric
                address  in  IPv4 dot notation or IPv6 colon
                notation or a network name.  Note that if  a
                network name is specified, only the first IP
                address returned for it will be used.   This
                may cause indeterminate behavior for network
                names that resolve  to  multiple  addresses.
                Therefore, use of an address is recommended.
                The Family  key  defaults  to  INET  (IPv4).
                IPv6 users who wish to also accept IPv6 con-
                nections should add additional  Family=inet6
                DaemonPortOptions  lines.  The InputMailFil-
                ters key overrides the default list of input
                mail  filters listed in the InputMailFilters
                option.  If multiple input mail filters  are
                required,  they  must  be separated by semi-
                colons (not  commas).   Modifier  can  be  a
                sequence  (without  any  delimiters)  of the
                following characters:












Sendmail Installation and Operation Guide         SMM:08-103


                    a         always require authentication
                    b         bind to interface through which mail has been received
                    c         perform hostname canonification (.cf)
                    f         require fully qualified hostname (.cf)
                    s         Run smtps (SMTP over SSL) instead of smtp
                    u         allow unqualified addresses (.cf)
                    A         disable AUTH (overrides 'a' modifier)
                    C         don't perform hostname canonification
                    E         disallow ETRN (see RFC 2476)
                    O         optional; if opening the socket fails ignore it
                    S         don't offer STARTTLS

                That is, one way to specify a  message  sub-
                mission  agent  (MSA)  that  always requires
                authentication is:

                    O DaemonPortOptions=Name=MSA, Port=587, M=Ea

                The modifiers that are marked  with  "(.cf)"
                have  only effect in the standard configura-
                tion file, in which they are  available  via
                ${daemon_flags}.   Notice:  Do  not  use the
                ``a'' modifier on a public  accessible  MTA!
                It  should  only  be  used for a MSA that is
                accessed by  authorized  users  for  initial
                mail submission.  Users must authenticate to
                use a MSA which has this option  turned  on.
                The  flags  ``c''  and  ``C'' can change the
                default for hostname canonification  in  the
                sendmail.cf file.  See the relevant documen-
                tation for FEATURE(nocanonify).   The  modi-
                fier  ``f''  disallows addresses of the form
                user@host   unless   they   are    submitted
                directly.  The flag ``u'' allows unqualified
                sender addresses, i.e., those without @host.
                ``b''  forces sendmail to bind to the inter-
                face  through  which  the  e-mail  has  been
                received for the outgoing connection.  WARN-
                ING: Use ``b'' only if outgoing mail can  be
                routed  through  the  incoming  connection's
                interface to its destination. No attempt  is
                made  to catch problems due to a misconfigu-
                ration of this parameter, use  it  only  for
                virtual hosting where each virtual interface
                can  connect  to  every  possible  location.
                This  will  also  override possible settings
                via ClientPortOptions.  Note, sendmail  will
                listen on a new socket for each occurence of
                the DaemonPortOptions option in a configura-
                tion  file.  The modifier ``O'' causes send-
                mail to ignore  a  socket  if  it  can't  be
                opened.   This  applies to failures from the
                socket(2) and bind(2) calls.










SMM:08-104         Sendmail Installation and Operation Guide


      DefaultAuthInfo
                [no  short  name]  Filename  that   contains
                default  authentication information for out-
                going connections. This  file  must  contain
                the user id, the authorization id, the pass-
                word (plain text), the realm and the list of
                mechanisms to use on separate lines and must
                be readable by root (or  the  trusted  user)
                only.  If no realm is specified, $j is used.
                If no mechanisms  are  specified,  the  list
                given  by  AuthMechanisms  is used.  Notice:
                this  option  is  deprecated  and  will   be
                removed  in  future  versions.  Moreover, it
                doesn't work for the MSP since it can't read
                the  file (the file must not be group/world-
                readable otherwise sendmail will  complain).
                Use  the authinfo ruleset instead which pro-
                vides more control over  the  usage  of  the
                data anyway.

      DefaultCharSet=charset
                [no  short  name]  When  a  message that has
                8-bit characters but is not in  MIME  format
                is  converted  to MIME (see the EightBitMode
                option) a character set must be included  in
                the  Content-Type:  header.   This character
                set is normally set from the Charset=  field
                of  the  mailer  descriptor.  If that is not
                set, the value of this option is  used.   If
                this   option   is   not   set,   the  value
                "unknown-8bit" is used.

      DataFileBufferSize=threshold
                [no short name] Set the threshold, in bytes,
                before   a   memory-based  queue  data  file
                becomes disk-based.   The  default  is  4096
                bytes.

      DeadLetterDrop=file
                [no  short name] Defines the location of the
                system-wide dead.letter file, formerly hard-
                coded   to  /usr/tmp/dead.letter.   If  this
                option is not set  (the  default),  sendmail
                will  not  attempt  to save to a system-wide
                dead.letter file  in  the  event  it  cannot
                bounce  the  mail to the user or postmaster.
                Instead, it will rename the qf  file  as  it
                has  in  the  past when the dead.letter file
                could not be opened.

      DefaultUser=user:group
                [u] Set the default userid  for  mailers  to
                user:group.  If group is omitted and user is










Sendmail Installation and Operation Guide         SMM:08-105


                a user name (as opposed to  a  numeric  user
                id)   the   default   group  listed  in  the
                /etc/passwd file for that user  is  used  as
                the  default group.  Both user and group may
                be numeric.  Mailers without the S  flag  in
                the mailer definition will run as this user.
                Defaults to 1:1.   The  value  can  also  be
                given as a symbolic user name.[19]

      DelayLA=LA
                [no short name] When the system load average
                exceeds LA, sendmail will sleep for one sec-
                ond on most SMTP commands and before accept-
                ing connections.

      DeliverByMin=time
                [0]  Set  minimum  time  for Deliver By SMTP
                Service Extension (RFC 2852).  If 0, no time
                is  listed, if less than 0, the extension is
                not offered, if greater than 0, it is listed
                as  minimum time for the EHLO keyword DELIV-
                ERBY.

      DeliveryMode=x
                [d] Deliver in mode x.  Legal modes are:

                    i   Deliver interactively (synchronously)
                    b   Deliver in background (asynchronously)
                    q   Just queue the message (deliver during queue run)
                    d   Defer delivery and all map lookups (deliver during queue run)

                Defaults to ``b'' if no option is specified,
                ``i''  if it is specified but given no argu-
                ment  (i.e.,   ``Od''   is   equivalent   to
                ``Odi'').   The  -v  command  line flag sets
                this to  i.   Note:  for  internal  reasons,
                ``i''  does  not work if a milter is enabled
                which can reject or delete  recipients.   In
                that case the mode will be changed to ``b''.

      DialDelay=sleeptime
                [no  short name] Dial-on-demand network con-
                nections can see timeouts if a connection is
                opened  before  the call is set up.  If this
                is set to an interval and a connection times
                out  on the first connection being attempted
                sendmail will sleep for this amount of  time
                and try again.  This should give your system
____________________
   [19]The  old g option has been combined into the Default-
User option.












SMM:08-106         Sendmail Installation and Operation Guide


                time to establish  the  connection  to  your
                service provider.  Units default to seconds,
                so "DialDelay=5" uses a five  second  delay.
                Defaults  to  zero  (no  retry).  This delay
                only applies to mailers  which  have  the  Z
                flag set.

      DirectSubmissionModifiers=modifiers
                Defines  ${daemon_flags} for direct (command
                line)  submissions.   If  not  set,   ${dae-
                mon_flags} is either "CC f" if the option -G
                is used or "c u" otherwise.  Note that  only
                the  the  "CC",  "c", "f", and "u" flags are
                checked.

      DontBlameSendmail=option,option,...
                [no short name] In order to  avoid  possible
                cracking   attempts  caused  by  world-  and
                group-writable files and directories,  send-
                mail  does  paranoid  checking  when opening
                most of its support files.  If for some rea-
                son  you absolutely must run with, for exam-
                ple, a group-writable /etc  directory,  then
                you  will have to turn off this checking (at
                the cost of making your system more vulnera-
                ble to attack).  The possible arguments have
                been  described  earlier.   The  details  of
                these  flags  are  described  above.  Use of
                this option is not recommended.

      DontExpandCnames
                [no short name] The standards say  that  all
                host  addresses  used in a mail message must
                be fully canonical.  For  example,  if  your
                host  is  named "Cruft.Foo.ORG" and also has
                an alias of "FTP.Foo.ORG", the  former  name
                must be used at all times.  This is enforced
                during host name canonification ($[  ...  $]
                lookups).  If this option is set, the proto-
                cols are ignored and the  "wrong"  thing  is
                done.   However,  the  IETF is moving toward
                changing this standard, so the behavior  may
                become  acceptable.   Please note that hosts
                downstream may still rewrite the address  to
                be the true canonical name however.

      DontInitGroups
                [no  short name] If set, sendmail will avoid
                using the initgroups(3) call.   If  you  are
                running  NIS,  this causes a sequential scan
                of the groups.byname map,  which  can  cause
                your  NIS server to be badly overloaded in a
                large domain.  The cost of this is that  the










Sendmail Installation and Operation Guide         SMM:08-107


                only  group  found  for  users will be their
                primary  group  (the  one  in  the  password
                file),  which  will make file access permis-
                sions somewhat  more  restrictive.   Has  no
                effect  on  systems  that  don't  have group
                lists.

      DontProbeInterfaces
                [no short name] Sendmail normally finds  the
                names  of  all  interfaces  active  on  your
                machine when it starts  up  and  adds  their
                name to the $=w class of known host aliases.
                If you have a large number of virtual inter-
                faces  or  if  your  DNS inverse lookups are
                slow  this  can  be  time  consuming.   This
                option turns off that probing.  However, you
                will need to be certain to include all vari-
                ant  names  in  the  $=w class by some other
                mechanism.  If  set  to  loopback,  loopback
                interfaces (e.g., lo0) will not be probed.

      DontPruneRoutes
                [R]  Normally,  sendmail  tries to eliminate
                any unnecessary explicit routes when sending
                an error message (as discussed in RFC 1123 S
                5.2.6).  For example, when sending an  error
                message to

                    <@known1,@known2,@known3:user@unknown>

                sendmail      will     strip     off     the
                "@known1,@known2" in order to make the route
                as  direct  as  possible.  However, if the R
                option is set, this will  be  disabled,  and
                the  mail  will be sent to the first address
                in the route, even if  later  addresses  are
                known.  This may be useful if you are caught
                behind a firewall.

      DoubleBounceAddress=error-address
                [no short name]  If  an  error  occurs  when
                sending  an  error  message,  send the error
                report (termed a "double bounce" because  it
                is an error "bounce" that occurs when trying
                to send another error "bounce") to the indi-
                cated   address.    The   address  is  macro
                expanded at the time of  delivery.   If  not
                set, defaults to "postmaster".  If set to an
                empty string, double bounces are dropped.

      EightBitMode=action
                [8] Set handling of eight-bit  data.   There
                are   two  kinds  of  eight-bit  data:  that










SMM:08-108         Sendmail Installation and Operation Guide


                declared as  such  using  the  BODY=8BITMIME
                ESMTP  declaration or the -B8BITMIME command
                line flag, and undeclared 8-bit  data,  that
                is,  input  that  just  happens  to be eight
                bits.  There are three basic operations that
                can  happen:  undeclared  8-bit  data can be
                automatically converted to  8BITMIME,  unde-
                clared  8-bit data can be passed as-is with-
                out conversion to MIME  (``just  send  8''),
                and  declared 8-bit data can be converted to
                7-bits for transmission  to  a  non-8BITMIME
                mailer.  The possible actions are:

                      s Reject undeclared 8-bit data (``strict'')
                      m Convert undeclared 8-bit data to MIME (``mime'')
                      p Pass undeclared 8-bit data (``pass'')

                In all cases properly declared 8BITMIME data
                will be converted to 7BIT as needed.

      ErrorHeader=file-or-message
                [E] Prepend error messages  with  the  indi-
                cated  message.   If it begins with a slash,
                it is assumed to be the pathname of  a  file
                containing  a  message  (this  is the recom-
                mended setting).  Otherwise, it is a literal
                message.   The  error file might contain the
                name, email address, and/or phone number  of
                a  local postmaster who could provide assis-
                tance to end users.  If the option is  miss-
                ing  or  null,  or  if it names a file which
                does not exist or which is not readable,  no
                message is printed.

      ErrorMode=x
                [e]  Dispose  of  errors  using mode x.  The
                values for x are:

                    p   Print error messages (default)
                    q   No messages, just give exit status
                    m   Mail back errors
                    w   Write back errors (mail if user not logged in)
                    e   Mail back errors (when applicable) and give zero exit stat always

                Note that the last mode, "e", is for Berknet
                error  processing  and should not be used in
                normal circumstances.  Note, too, that  mode
                "q",   only  applies  to  errors  recognized
                before sendmail forks for background  deliv-
                ery.

      FallbackMXhost=fallbackhost
                [V] If specified, the fallbackhost acts like










Sendmail Installation and Operation Guide         SMM:08-109


                a very low priority MX on  every  host.   MX
                records  will  be  looked  up for this host,
                unless the  name  is  surrounded  by  square
                brackets.   This  is  intended to be used by
                sites with poor network connectivity.   Mes-
                sages  which are undeliverable due to tempo-
                rary address failures  (e.g.,  DNS  failure)
                also go to the FallbackMXhost.

      FallBackSmartHost=hostname
                If  specified, the FallBackSmartHost will be
                used in a last-ditch effort for  each  host.
                This  is  intended  to be used by sites with
                "fake internal DNS", e.g., a  company  whose
                DNS  accurately  reflects  the  world inside
                that company's domain but not outside.

      FastSplit [no short name] If set to  a  value  greater
                than  zero  (the  default  is  one), it sup-
                presses the MX  lookups  on  addresses  when
                they  are  initially  sorted,  i.e., for the
                first  delivery   attempt.    This   usually
                results  in faster envelope splitting unless
                the MX records are readily  available  in  a
                local DNS cache.  To enforce initial sorting
                based on MX records set FastSplit  to  zero.
                If  the  mail is submitted directly from the
                command line, then the value also limits the
                number   of   processes   to   deliver   the
                envelopes; if  more  envelopes  are  created
                they  are  only  queued up and must be taken
                care of by a queue run.  Since  the  default
                submission method is via SMTP (either from a
                MUA or via the MSP), the value of  FastSplit
                is  seldom  used to limit the number of pro-
                cesses to deliver the envelopes.

      ForkEachJob
                [Y] If set, deliver each  job  that  is  run
                from the queue in a separate process.

      ForwardPath=path
                [J]  Set  the  path for searching for users'
                .forward files.  The  default  is  "$z/.for-
                ward".   Some sites that use the automounter
                may prefer  to  change  this  to  "/var/for-
                ward/$u" to search a file with the same name
                as the user in a system directory.   It  can
                also be set to a sequence of paths separated
                by colons; sendmail stops at the first  file
                it  can  successfully  and safely open.  For
                example, "/var/forward/$u:$z/.forward"  will
                search  first  in  /var/forward/username and










SMM:08-110         Sendmail Installation and Operation Guide


                then in ~username/.forward (but only if  the
                first file does not exist).

      HeloName=name
                [no  short name] Set the name to be used for
                HELO/EHLO (instead of $j).

      HoldExpensive
                [c] If an outgoing mailer is marked as being
                expensive, don't connect immediately.

      HostsFile=path
                [no  short name] The path to the hosts data-
                base, normally "/etc/hosts".  This option is
                only  consulted when sendmail is canonifying
                addresses, and then only when "files" is  in
                the  "hosts"  service switch entry.  In par-
                ticular, this file is never used when  look-
                ing  up  host  addresses;  that is under the
                control of the system gethostbyname(3)  rou-
                tine.

      HostStatusDirectory=path
                [no  short  name]  The  location of the long
                term host  status  information.   When  set,
                information about the status of hosts (e.g.,
                host down or not accepting connections) will
                be  shared  between  all sendmail processes;
                normally,  this  information  is  only  held
                within  a  single  queue  run.   This option
                requires a connection cache of at least 1 to
                function.  If the option begins with a lead-
                ing `/', it is an absolute pathname;  other-
                wise,  it  is  relative  to  the  mail queue
                directory.   A  suggested  value  for  sites
                desiring  persistent  host status is ".host-
                stat" (i.e., a  subdirectory  of  the  queue
                directory).

      IgnoreDots
                [i]  Ignore dots in incoming messages.  This
                is always disabled (that is, dots are always
                accepted) when reading SMTP mail.

      InputMailFilters=name,name,...
                A  comma  separated  list  of  filters which
                determines which filters (see the "X -- Mail
                Filter  (Milter)  Definitions"  section) and
                the invocation sequence  are  contacted  for
                incoming SMTP messages.  If none are set, no
                filters will be contacted.












Sendmail Installation and Operation Guide         SMM:08-111


      LDAPDefaultSpec=spec
                [no short name] Sets a default map  specifi-
                cation for LDAP maps.  The value should only
                contain LDAP specific settings such  as  "-h
                host  -p port -d bindDN".  The settings will
                be used for all LDAP maps unless  the  indi-
                vidual  map  specification  overrides a set-
                ting.  This option should be set before  any
                LDAP maps are defined.

      LogLevel=n
                [L] Set the log level to n.  Defaults to 9.

      Mxvalue   [no  long version] Set the macro x to value.
                This is intended only for use from the  com-
                mand line.  The -M flag is preferred.

      MailboxDatabase
                [no  short  name]  Type  of  lookup  to find
                information about local mailboxes,  defaults
                to  ``pw'' which uses getpwnam.  Other types
                can be introduced  by  adding  them  to  the
                source code, see libsm/mbdb.c for details.

      UseMSP    [no  short name] Use as mail submission pro-
                gram, i.e., allow group writable queue files
                if  the  group is the same as that of a set-
                group-ID  sendmail  binary.   See  the  file
                sendmail/SECURITY  in  the distribution tar-
                ball.

      MatchGECOS
                [G] Allow fuzzy matching on the GECOS field.
                If this flag is set, and the usual user name
                lookups fail (that is,  there  is  no  alias
                with   this  name  and  a  getpwnam  fails),
                sequentially search the password file for  a
                matching  entry  in  the  GECOS field.  This
                also requires that MATCHGECOS be  turned  on
                during compilation.  This option is not rec-
                ommended.

      MaxAliasRecursion=N
                [no short name] The maximum depth  of  alias
                recursion (default: 10).

      MaxDaemonChildren=N
                [no short name] If set, sendmail will refuse
                connections when it has more than N children
                processing  incoming mail or automatic queue
                runs.  This does not  limit  the  number  of
                outgoing connections.  If the default Deliv-
                eryMode (background) is used, then  sendmail










SMM:08-112         Sendmail Installation and Operation Guide


                may  create  an  almost  unlimited number of
                children (depending on the number of  trans-
                actions  and the relative execution times of
                mail receiption and mail delivery).  If  the
                limit  should  be enforced, then a Delivery-
                Mode other than background must be used.  If
                not  set, there is no limit to the number of
                children -- that is, the system load average
                controls this.

      MaxHeadersLength=N
                [no  short  name]  The maximum length of the
                sum of all headers.  This  can  be  used  to
                prevent  a  denial  of  service attack.  The
                default is no limit.

      MaxHopCount=N
                [h] The maximum hop  count.   Messages  that
                have  been  processed  more than N times are
                assumed to be in a loop  and  are  rejected.
                Defaults to 25.

      MaxMessageSize=N
                [no  short name] Specify the maximum message
                size to be  advertised  in  the  ESMTP  EHLO
                response.  Messages larger than this will be
                rejected.  If set to a  value  greater  than
                zero,  that value will be listed in the SIZE
                response, otherwise SIZE  is  advertised  in
                the ESMTP EHLO response without a parameter.

      MaxMimeHeaderLength=N[/M]
                [no  short  name] Sets the maximum length of
                certain MIME header field values to N  char-
                acters.  These MIME header fields are deter-
                mined by being a member of class {checkMIME-
                TextHeaders},  which currently contains only
                the header Content-Description.  For some of
                these  headers  which  take  parameters, the
                maximum length of each parameter is set to M
                if  specified.   If /M is not specified, one
                half of N will be used.  By  default,  these
                values  are 2048 and 1024, respectively.  To
                allow any length, a value of 0 can be speci-
                fied.

      MaxNOOPCommands=N
                Override  the default of MAXNOOPCOMMANDS for
                the number of useless commands, see  Section
                "Measures    against   Denial   of   Service
                Attacks".












Sendmail Installation and Operation Guide         SMM:08-113


      MaxQueueChildren=N
                [no short name] When set,  this  limits  the
                number  of concurrent queue runner processes
                to N.  This helps to control the  amount  of
                system  resources  used  when processing the
                queue.  When there are multiple queue groups
                defined  and  the total number of queue run-
                ners for these  queue  groups  would  exceed
                MaxQueueChildren  then the queue groups will
                not all run concurrently. That is, some por-
                tion  of  the  queue groups will run concur-
                rently such that MaxQueueChildren  will  not
                be   exceeded,  while  the  remaining  queue
                groups will be run  later  (in  round  robin
                order).  See also MaxRunnersPerQueue and the
                section Queue  Group  Declaration.   Notice:
                sendmail  does  not  count  individual queue
                runners, but only sets of processes that act
                on  a workgroup.  Hence the actual number of
                queue runners may be lower  than  the  limit
                imposed  by MaxQueueChildren.  This discrep-
                ancy can be large if some queue runners have
                to  wait  for  a  slow  server  and if short
                intervals are used.

      MaxQueueRunSize=N
                [no short name] The maximum number  of  jobs
                that  will  be  processed  in a single queue
                run.  If not set, there is no limit  on  the
                size.   If  you  have very large queues or a
                very short queue run interval this could  be
                unstable.   However,  since the first N jobs
                in queue directory  order  are  run  (rather
                than  the  N  highest  priority  jobs)  this
                should be set as high as possible  to  avoid
                "losing"  jobs  that  happen to fall late in
                the queue directory.  Note: this option also
                restricts  the  number of entries printed by
                mailq.  That is, if MaxQueueRunSize  is  set
                to  a  value N larger than zero, then only N
                entries are printed per queue group.

      MaxRecipientsPerMessage=N
                [no short name] The maximum number of recip-
                ients  that  will be accepted per message in
                an SMTP transaction.  Note: setting this too
                low  can  interfere  with  sending mail from
                MUAs that use SMTP for  initial  submission.
                If  not set, there is no limit on the number
                of recipients per envelope.

      MaxRunnersPerQueue=N
                [no  short  name]  This  sets  the   default










SMM:08-114         Sendmail Installation and Operation Guide


                maximum  number  of  queue runners for queue
                groups.  Up to N queue runners will work  in
                parallel  on a queue group's messages.  This
                is useful where the processing of a  message
                in  the  queue might delay the processing of
                subsequent messages. Such a delay may be the
                result of non-erroneous situations such as a
                low bandwidth connection.  May be overridden
                on  a  per  queue group basis by setting the
                Runners option; see the section Queue  Group
                Declaration.  The default is 1 when not set.

      MeToo     [m] Send to me too, even if I am in an alias
                expansion.  This option  is  deprecated  and
                will be removed from a future version.

      Milter    [no  short  name]  This  option  has several
                sub(sub)options.  The names  of  the  subop-
                tions  are  separated by dots.  At the first
                level the following options are available:

                    LogLevel   Log level for input mail filter actions, defaults to LogLevel.
                    macros     Specifies list of macro to transmit to filters.
                               See list below.

                The ``macros'' option has the following sub-
                options  which  specify the list of macro to
                transmit to milters after  a  certain  event
                occurred.

                    connect   After session connection start
                    helo      After EHLO/HELO command
                    envfrom   After MAIL From command
                    envrcpt   After RCPT To command
                    data      After DATA command.
                    eoh       After DATA command and header
                    eom       After DATA command and terminating ``.''

                By  default  the  lists of macros are empty.
                Example:

                    O Milter.LogLevel=12
                    O Milter.macros.connect=j, _, {daemon_name}


      MinFreeBlocks=N
                [b] Insist on at least N blocks free on  the
                filesystem that holds the queue files before
                accepting  email  via  SMTP.   If  there  is
                insufficient  space  sendmail  gives  a  452
                response to the MAIL command.  This  invites
                the sender to try again later.











Sendmail Installation and Operation Guide         SMM:08-115


      MinQueueAge=age
                [no  short  name]  Don't  process any queued
                jobs that have been in the queue  less  than
                the   indicated   time  interval.   This  is
                intended to allow you to get  responsiveness
                by  processing  the  queue fairly frequently
                without thrashing your system by trying jobs
                too  often.   The default units are minutes.
                Note: This option is ignored for queue  runs
                that  select  a  subset  of the queue, i.e.,
                "-q[!][I|R|S|Q][string]"

      MustQuoteChars=s
                [no short name] Sets the list of  characters
                that  must  be quoted if used in a full name
                that is in the phrase  part  of  a  ``phrase
                <address>''  syntax.  The default is ``'.''.
                The  characters  ``@,;:\()[]''  are   always
                added to this list.

      NiceQueueRun
                [no  short  name] The priority of queue run-
                ners (nice(3)).  This value must be  greater
                or equal zero.

      NoRecipientAction
                [no  short name] The action to take when you
                receive a message that has no valid  recipi-
                ent  headers (To:, Cc:, Bcc:, or Apparently-
                To: -- the last included for  back  compati-
                bility  with old sendmails).  It can be None
                to pass the  message  on  unmodified,  which
                violates  the  protocol, Add-To to add a To:
                header with any recipients it  can  find  in
                the envelope (which might expose Bcc: recip-
                ients), Add-Apparently-To to add  an  Appar-
                ently-To: header (this is only for back-com-
                patibility and  is  officially  deprecated),
                Add-To-Undisclosed  to  add  a  header  "To:
                undisclosed-recipients:;" to make the header
                legal  without  disclosing anything, or Add-
                Bcc to add an empty Bcc: header.

      OldStyleHeaders
                [o] Assume that the headers may  be  in  old
                format,  i.e.,  spaces  delimit names.  This
                actually turns on an adaptive algorithm:  if
                any  recipient  address  contains  a  comma,
                parenthesis, or angle bracket,  it  will  be
                assumed  that commas already exist.  If this
                flag is not on, only commas  delimit  names.
                Headers   are   always  output  with  commas
                between the names.  Defaults to off.










SMM:08-116         Sendmail Installation and Operation Guide


      OperatorChars=charlist
                [$o macro] The list of characters  that  are
                considered to be "operators", that is, char-
                acters that delimit  tokens.   All  operator
                characters   are   tokens   by   themselves;
                sequences  of  non-operator  characters  are
                also  tokens.   White space characters sepa-
                rate tokens but are not tokens themselves --
                for example, "AAA.BBB" has three tokens, but
                "AAA BBB" has two.  If  not  set,  Operator-
                Chars defaults to ".:@[]"; additionally, the
                characters "()<>,;"  are  always  operators.
                Note  that  OperatorChars must be set in the
                configuration file before any rulesets.

      PidFile=filename
                [no short name] Filename of  the  pid  file.
                (default  is  _PATH_SENDMAILPID).  The file-
                name is macro-expanded before it is  opened,
                and unlinked when sendmail exits.

      PostmasterCopy=postmaster
                [P] If set, copies of error messages will be
                sent to  the  named  postmaster.   Only  the
                header   of  the  failed  message  is  sent.
                Errors resulting from messages with a  nega-
                tive  precedence  will  not  be sent.  Since
                most errors are user problems, this is prob-
                ably  not  a  good  idea on large sites, and
                arguably contains all sorts of privacy  vio-
                lations,  but  it  seems  to be popular with
                certain  operating  systems  vendors.    The
                address  is  macro  expanded  at the time of
                delivery.  Defaults to no postmaster copies.

      PrivacyOptions=opt,opt,...
                [p] Set the privacy options.  ``Privacy'' is
                really  a misnomer; many of these are just a
                way of insisting on  stricter  adherence  to
                the  SMTP  protocol.   The  options  can  be
                selected from:






















Sendmail Installation and Operation Guide         SMM:08-117


                    public              Allow open access
                    needmailhelo        Insist on HELO or EHLO command before MAIL
                    needexpnhelo        Insist on HELO or EHLO command before EXPN
                    noexpn              Disallow EXPN entirely, implies noverb.
                    needvrfyhelo        Insist on HELO or EHLO command before VRFY
                    novrfy              Disallow VRFY entirely
                    noetrn              Disallow ETRN entirely
                    noverb              Disallow VERB entirely
                    restrictmailq       Restrict mailq command
                    restrictqrun        Restrict -q command line flag
                    restrictexpand      Restrict -bv and -v command line flags
                    noreceipts          Don't return success DSNs[20]
                    nobodyreturn        Don't return the body of a message with DSNs
                    goaway              Disallow essentially all SMTP status queries
                    authwarnings        Put X-Authentication-Warning: headers in messages
                                        and log warnings
                    noactualrecipient   Don't put X-Actual-Recipient lines in DSNs
                                        which reveal the actual account that addresses map to.

                The  "goaway"  pseudo-flag  sets  all  flags
                except    "noreceipts",     "restrictmailq",
                "restrictqrun",  "restrictexpand", "noetrn",
                and "nobodyreturn".  If mailq is restricted,
                only  people  in the same group as the queue
                directory can print  the  queue.   If  queue
                runs are restricted, only root and the owner
                of the queue directory can  run  the  queue.
                The  "restrictexpand"  pseudo-flag instructs
                sendmail to drop  privileges  when  the  -bv
                option  is  given  by  users who are neither
                root nor the  TrustedUser  so  users  cannot
                read private aliases, forwards, or :include:
                files.  It will add the "NonRootSafeAddr" to
                the  "DontBlameSendmail"  option  to prevent
                misleading unsafe address warnings.  It also
                overrides  the  -v  (verbose)  command  line
                option  to  prevent   information   leakage.
                Authentication  Warnings  add warnings about
                various   conditions   that   may   indicate
                attempts  to  spoof the mail system, such as
                using a non-standard queue directory.

      ProcessTitlePrefix=string
                [no short name]  Prefix  the  process  title
                shown  on  'ps'  listings  with string.  The
                string will be macro processed.


____________________
   [20]N.B.: the noreceipts flag turns off support  for  RFC
1891 (Delivery Status Notification).












SMM:08-118         Sendmail Installation and Operation Guide


      QueueDirectory=dir
                [Q] The  QueueDirectory  option  serves  two
                purposes.  First, it specifies the directory
                or set  of  directories  that  comprise  the
                default  queue  group.  Second, it specifies
                the directory D which is the ancestor of all
                queue  directories,  and which sendmail uses
                as  its  current  working  directory.   When
                sendmail  dumps  core,  it  leaves  its core
                files in D.  There are two  cases.   If  dir
                ends      with      an     asterisk     (eg,
                /var/spool/mqueue/qd*),  then  all  of   the
                directories or symbolic links to directories
                beginning  with  `qd'  in  /var/spool/mqueue
                will  be  used  as  queue directories of the
                default queue group,  and  /var/spool/mqueue
                will  be  used  as  the working directory D.
                Otherwise, dir must name a  directory  (usu-
                ally  /var/spool/mqueue):  the default queue
                group consists of the single queue directory
                dir,  and  the working directory D is set to
                dir.  To define additional groups  of  queue
                directories,  use the configuration file `Q'
                command.  Do not change the queue  directory
                structure while sendmail is running.

      QueueFactor=factor
                [q]  Use factor as the multiplier in the map
                function to decide when  to  just  queue  up
                jobs  rather  than  run them.  This value is
                divided by the difference between  the  cur-
                rent load average and the load average limit
                (QueueLA option) to  determine  the  maximum
                message   priority   that   will   be  sent.
                Defaults to 600000.

      QueueLA=LA
                [x] When the system load average exceeds  LA
                and  the  QueueFactor  (q) option divided by
                the difference in the current  load  average
                and the QueueLA option plus one is less than
                the priority of the message, just queue mes-
                sages   (i.e.,  don't  try  to  send  them).
                Defaults to 8 multiplied by  the  number  of
                processors online on the system (if that can
                be determined).

      QueueFileMode=mode
                [no  short  name]  Default  permissions  for
                queue  files  (octal).  If not set, sendmail
                uses 0600 unless its real and effective  uid
                are different in which case it uses 0644.











Sendmail Installation and Operation Guide         SMM:08-119


      QueueSortOrder=algorithm
                [no  short name] Sets the algorithm used for
                sorting the queue.  Only the first character
                of  the  value  is  used.   Legal values are
                "host" (to order by the name  of  the  first
                host  name  of  the first recipient), "file-
                name" (to order by the  name  of  the  queue
                file  name), "time" (to order by the submis-
                sion/creation time), "random" (to order ran-
                domly), "modification" (to order by the mod-
                ification time of the qf file (older entries
                first)),  "none" (to not order), and "prior-
                ity" (to order by message  priority).   Host
                ordering  makes better use of the connection
                cache, but may tend to process low  priority
                messages  that go to a single host over high
                priority messages that go to several  hosts;
                it  probably  shouldn't be used on slow net-
                work links.  Filename and modification  time
                ordering  saves  the overhead of reading all
                of the  queued  items  before  starting  the
                queue   run.    Creation  (submission)  time
                ordering is almost always a bad idea,  since
                it  allows large, bulk mail to go out before
                smaller, personal mail, but may have  appli-
                cability  on  some hosts with very fast con-
                nections.  Random is useful if several queue
                runners  are  started  by  hand which try to
                drain the same queue  since  odds  are  they
                will  be  working  on different parts of the
                queue at the same time.   Priority  ordering
                is the default.

      QueueTimeout=timeout
                [T]  A  synonym  for  "Timeout.queuereturn".
                Use that form instead of the  "QueueTimeout"
                form.

      RandFile  [no short name] Name of file containing ran-
                dom data or the name of the UNIX  socket  if
                EGD  is used.  A (required) prefix "egd:" or
                "file:"  specifies   the   type.    STARTTLS
                requires  this  filename if the compile flag
                HASURANDOMDEV  is   not   set   (see   send-
                mail/README).

      ResolverOptions=options
                [I] Set resolver options.  Values can be set
                using +flag and  cleared  using  -flag;  the
                flags  can  be  "debug",  "aaonly", "usevc",
                "primary", "igntc",  "recurse",  "defnames",
                "stayopen",  "use_inet6",  or "dnsrch".  The
                string "HasWildcardMX" (without a  +  or  -)










SMM:08-120         Sendmail Installation and Operation Guide


                can   be  specified  to  turn  off  matching
                against MX records when doing name canonifi-
                cations.   The string "WorkAroundBrokenAAAA"
                (without a + or -) can be specified to  work
                around  some broken nameservers which return
                SERVFAIL (a  temporary  failure)  on  T_AAAA
                (IPv6)  lookups.  Notice: it might be neces-
                sary to apply the same (or similar)  options
                to submit.cf too.

      RequiresDirfsync
                [no  short  name] This option can be used to
                override    the    compile     time     flag
                REQUIRES_DIR_FSYNC  at runtime by setting it
                to false.  If the compile time flag  is  not
                set,  the option is ignored.  The flag turns
                on support for file systems that require  to
                call  fsync()  for  a directory if the meta-
                data in it has been changed.  This should be
                turned  on  at  least  for older versions of
                ReiserFS;  it  is  enabled  by  default  for
                Linux.   According  to some information this
                flag is not needed anymore for kernel 2.4.16
                and newer.

      RrtImpliesDsn
                [R]  If  this  option  is  set,  a  "Return-
                Receipt-To:" header causes the request of  a
                DSN, which is sent to the envelope sender as
                required by RFC 1891,  not  to  the  address
                given in the header.

      RunAsUser=user
                [no  short name] The user parameter may be a
                user name (looked up in  /etc/passwd)  or  a
                numeric   user  id;  either  form  can  have
                ":group"  attached  (where  group   can   be
                numeric  or symbolic).  If set to a non-zero
                (non-root) value, sendmail  will  change  to
                this  user  id  shortly  after  startup[21].
                This avoids  a  certain  class  of  security
                problems.   However,  this  means  that  all
                ".forward" and  ":include:"  files  must  be
                readable by the indicated user and all files
                to be written must be writable by user Also,
                all  file  and  program  deliveries  will be
                marked    unsafe    unless    the     option
____________________
   [21]When running as a daemon, it changes to this user af-
ter accepting a connection but before reading any SMTP  com-
mands.












Sendmail Installation and Operation Guide         SMM:08-121


                DontBlameSendmail=NonRootSafeAddr is set, in
                which case the  delivery  will  be  done  as
                user.   It  is  also  incompatible  with the
                SafeFileEnvironment option.  In other words,
                it  may not actually add much to security on
                an average system, and may in  fact  detract
                from  security  (because  other file permis-
                sions must be loosened).  However, it should
                be  useful  on  firewalls  and  other places
                where users  don't  have  accounts  and  the
                aliases file is well constrained.

      RecipientFactor=fact
                [y]  The  indicated  factor  is added to the
                priority (thus lowering the priority of  the
                job)  for  each  recipient, i.e., this value
                penalizes jobs with large numbers of recipi-
                ents.  Defaults to 30000.

      RefuseLA=LA
                [X] When the system load average exceeds LA,
                refuse incoming SMTP connections.   Defaults
                to 12 multiplied by the number of processors
                online on the system (if that can be  deter-
                mined).

      RejectLogInterval=timeout
                [no  short  name] Log interval when refusing
                connections for this long (default: 3h).

      RetryFactor=fact
                [Z] The factor  is  added  to  the  priority
                every  time  a job is processed.  Thus, each
                time a job is processed, its  priority  will
                be  decreased  by  the  indicated value.  In
                most environments this should  be  positive,
                since  hosts that are down are all too often
                down for a long time.  Defaults to 90000.

      SafeFileEnvironment=dir
                [no short name] If this option is set, send-
                mail will do a chroot(2) call into the indi-
                cated  directory  before  doing   any   file
                writes.   If  the file name specified by the
                user begins with dir, that partial path name
                will be stripped off before writing, so (for
                example) if the SafeFileEnvironment variable
                is   set   to   "/safe"   then   aliases  of
                "/safe/logs/file" and "/logs/file"  actually
                indicate  the  same  file.  Additionally, if
                this option  is  set,  sendmail  refuses  to
                deliver to symbolic links.











SMM:08-122         Sendmail Installation and Operation Guide


      SaveFromLine
                [f]  Save  UNIX-style  "From"  lines  at the
                front of headers.  Normally they are assumed
                redundant and discarded.

      SendMimeErrors
                [j] If set, send error messages in MIME for-
                mat (see RFC 2045 and RFC 1344 for details).
                If  disabled,  sendmail  will not return the
                DSN keyword in response to an EHLO and  will
                not do Delivery Status Notification process-
                ing as described in RFC 1891.

      ServerCertFile
                [no short name] File containing the certifi-
                cate  of  the server, i.e., this certificate
                is used when sendmail acts as  server  (used
                for STARTTLS).

      ServerKeyFile
                [no  short name] File containing the private
                key  belonging  to  the  server  certificate
                (used for STARTTLS).

      ServiceSwitchFile=filename
                [no  short name] If your host operating sys-
                tem has a service switch abstraction  (e.g.,
                /etc/nsswitch.conf     on     Solaris     or
                /etc/svc.conf on Ultrix and DEC OSF/1)  that
                service will be consulted and this option is
                ignored.  Otherwise, this is the name  of  a
                file  that provides the list of methods used
                to implement particular services.  The  syn-
                tax is a series of lines, each of which is a
                sequence of words.  The first  word  is  the
                service  name,  and following words are ser-
                vice types.  The services that sendmail con-
                sults  directly  are  "aliases" and "hosts."
                Service types can  be  "dns",  "nis",  "nis-
                plus",  or "files" (with the caveat that the
                appropriate  support  must  be  compiled  in
                before  the  service can be referenced).  If
                ServiceSwitchFile  is  not   specified,   it
                defaults  to  /etc/mail/service.switch.   If
                that file does not exist, the default switch
                is:

                    aliases             files
                    hosts               dns nis files

                The    default   file   is   "/etc/mail/ser-
                vice.switch".











Sendmail Installation and Operation Guide         SMM:08-123


      SevenBitInput
                [7] Strip input to seven bits  for  compati-
                bility  with old systems.  This shouldn't be
                necessary.

      SharedMemoryKey
                [no short name] Key to use for shared memory
                segment;  if  not  set (or 0), shared memory
                will not be used.  If set to -1 sendmail can
                select  a  key  itself  provided  that  also
                SharedMemoryKeyFile is set.   Requires  sup-
                port  for  shared memory to be compiled into
                sendmail.  If this option is  set,  sendmail
                can   share   some  data  between  different
                instances.   For  example,  the  number   of
                entries  in  a queue directory or the avail-
                able space in a file  system.   This  allows
                for  more efficient program execution, since
                only one process needs to  update  the  data
                instead of each individual process gathering
                the data each time it is required.

      SharedMemoryKeyFile
                [no short name] If SharedMemoryKey is set to
                -1  then  the  automatically selected shared
                memory key will be stored in  the  specified
                file.

      SingleLineFromHeader
                [no  short  name]  If  set, From: lines that
                have embedded newlines  are  unwrapped  onto
                one  line.  This is to get around a botch in
                Lotus Notes that  apparently  cannot  under-
                stand legally wrapped RFC 822 headers.

      SingleThreadDelivery
                [no  short  name]  If  set, a client machine
                will never try to open two SMTP  connections
                to a single server machine at the same time,
                even in different processes.   That  is,  if
                another  sendmail is already talking to some
                host a new sendmail will  not  open  another
                connection.    This  property  is  of  mixed
                value; although this reduces the load on the
                other  machine,  it  can  cause  mail  to be
                delayed (for example,  if  one  sendmail  is
                delivering  a  huge message, other sendmails
                won't be able to send even small  messages).
                Also,  it  requires  another file descriptor
                (for the lock file) per connection,  so  you
                may  have  to reduce the ConnectionCacheSize
                option to avoid running out  of  per-process
                file      descriptors.      Requires     the










SMM:08-124         Sendmail Installation and Operation Guide


                HostStatusDirectory option.

      SmtpGreetingMessage=message
                [$e macro] The message printed when the SMTP
                server  starts up.  Defaults to "$j Sendmail
                $v ready at $b".

      SoftBounce
                If set, issue temporary errors (4xy) instead
                of permanent errors (5xy).  This can be use-
                ful during testing of a new configuration to
                avoid erroneous bouncing of mails.

      StatusFile=file
                [S]  Log  summary  statistics  in  the named
                file.  If no file name is  specified,  "sta-
                tistics"  is  used.   If not set, no summary
                statistics are saved.  This  file  does  not
                grow  in  size.  It can be printed using the
                mailstats(8) program.

      SuperSafe [s] This option can be set to  True,  False,
                Interactive, or PostMilter.  If set to True,
                sendmail will  be  super-safe  when  running
                things,  i.e.,  always instantiate the queue
                file, even if you are going to attempt imme-
                diate  delivery.   Sendmail always instanti-
                ates the queue file before returning control
                to the client under any circumstances.  This
                should really always be set  to  True.   The
                Interactive  value  has  been  introduced in
                8.12 and can be used together with Delivery-
                Mode=i.  It skips some synchronization calls
                which are effectively doubled  in  the  code
                execution  path  for  this  mode.  If set to
                PostMilter,  sendmail  defers  synchronizing
                the  queue  file until any milters have sig-
                naled acceptance of the message.  PostMilter
                is  useful  only when sendmail is running as
                an SMTP server; in all other  situations  it
                acts the same as True.

      TLSSrvOptions
                [no  short  name]  List  of options for SMTP
                STARTTLS for the server consisting of single
                characters  with  intervening white space or
                commas.  The flag ``V'' disables client ver-
                ification,  and  hence it is not possible to
                use a client certificate for relaying.  Cur-
                rently there are no other flags available.

      TempFileMode=mode
                [F]  The  file  mode  for  transcript files,










Sendmail Installation and Operation Guide         SMM:08-125


                files to which sendmail  delivers  directly,
                files  in  the HostStatusDirectory, and Sta-
                tusFile.  It  is  interpreted  in  octal  by
                default.  Defaults to 0600.

      Timeout.type=timeout
                [r; subsumes old T option as well] Set time-
                out values.  For more information, see  sec-
                tion 4.1.

      TimeZoneSpec=tzinfo
                [t]  Set  the local time zone info to tzinfo
                -- for  example,  "PST8PDT".   Actually,  if
                this is not set, the TZ environment variable
                is cleared (so the system default is  used);
                if  set  but null, the user's TZ variable is
                used, and if set and non-null the  TZ  vari-
                able is set to this value.

      TrustedUser=user
                [no  short name] The user parameter may be a
                user name (looked up in  /etc/passwd)  or  a
                numeric user id.  Trusted user for file own-
                ership and starting  the  daemon.   If  set,
                generated  alias  databases  and the control
                socket (if configured) will automatically be
                owned by this user.

      TryNullMXList
                [w]  If  this system is the "best" (that is,
                lowest preference) MX for a given host,  its
                configuration  rules  should normally detect
                this situation and treat that condition spe-
                cially  by  forwarding  the  mail  to a UUCP
                feed, treating it  as  local,  or  whatever.
                However,  in  some  cases  (such as Internet
                firewalls) you may want to  try  to  connect
                directly to that host as though it had no MX
                records at all.  Setting this option  causes
                sendmail  to try this.  The downside is that
                errors in your configuration are  likely  to
                be  diagnosed  as "host unknown" or "message
                timed out" instead of something  more  mean-
                ingful.  This option is disrecommended.

      UnixFromLine=fromline
                [$l  macro]  Defines  the  format  used when
                sendmail must add a  UNIX-style  From_  line
                (that      is,      a     line     beginning
                "From<space>user").  Defaults  to  "From  $g
                $d".   Don't  change this unless your system
                uses a different UNIX mailbox  format  (very
                unlikely).










SMM:08-126         Sendmail Installation and Operation Guide


      UnsafeGroupWrites
                [no  short name] If set (default), :include:
                and .forward files that are  group  writable
                are  considered "unsafe", that is, they can-
                not reference programs or write directly  to
                files.   World  writable :include: and .for-
                ward files are  always  unsafe.   Note:  use
                DontBlameSendmail  instead;  this  option is
                deprecated.

      UseErrorsTo
                [l] If there is an "Errors-To:" header, send
                error   messages  to  the  addresses  listed
                there.  They normally  go  to  the  envelope
                sender.   Use of this option causes sendmail
                to violate RFC 1123.  This option is disrec-
                ommended and deprecated.

      UserDatabaseSpec=udbspec
                [U] The user database specification.

      Verbose   [v]  Run  in  verbose mode.  If this is set,
                sendmail adjusts options HoldExpensive  (old
                c) and DeliveryMode (old d) so that all mail
                is delivered completely in a single  job  so
                that   you   can  see  the  entire  delivery
                process.  Option Verbose should never be set
                in  the  configuration  file; it is intended
                for command line use only.   Note  that  the
                use  of option Verbose can cause authentica-
                tion information to leak, if you use a send-
                mail client to authenticate to a server.  If
                the authentication mechanism uses plain text
                passwords (as with LOGIN or PLAIN), then the
                password could  be  compromised.   To  avoid
                this,  do  not  install sendmail set-user-ID
                root, and disable the VERB SMTP command with
                a suitable PrivacyOptions setting.

      XscriptFileBufferSize=threshold
                [no short name] Set the threshold, in bytes,
                before a memory-based queue transcript  file
                becomes  disk-based.   The  default  is 4096
                bytes.

      All options can be specified on the command line using
      the  -O  or  -o  flag, but most will cause sendmail to
      relinquish its set-user-ID permissions.   The  options
      that will not cause this are SevenBitInput [7], Eight-
      BitMode  [8],  MinFreeBlocks  [b],  CheckpointInterval
      [C],  DeliveryMode [d], ErrorMode [e], IgnoreDots [i],
      SendMimeErrors [j], LogLevel [L], MeToo [m], OldStyle-
      Headers   [o],   PrivacyOptions  [p],  SuperSafe  [s],










Sendmail Installation and Operation Guide         SMM:08-127


      Verbose  [v],  QueueSortOrder,  MinQueueAge,  Default-
      CharSet, Dial Delay, NoRecipientAction, ColonOkInAddr,
      MaxQueueRunSize,  SingleLineFromHeader,  and  AllowBo-
      gusHELO.   Actually,  PrivacyOptions  [p] given on the
      command line are added to those already  specified  in
      the  sendmail.cf  file,  i.e.,  they  can't  be reset.
      Also, M (define macro) when defining the r or s macros
      is also considered "safe".

   5.7.  P -- Precedence Definitions

           Values for the "Precedence:" field may be defined
      using the P control line.  The syntax  of  this  field
      is:

          Pname=num

      When  the  name is found in a "Precedence:" field, the
      message class is set  to  num.   Higher  numbers  mean
      higher  precedence.   Numbers  less than zero have the
      special property that if an error occurs  during  pro-
      cessing  the body of the message will not be returned;
      this is expected to be used for "bulk"  mail  such  as
      through  mailing  lists.   The  default  precedence is
      zero.  For example, our list of precedences is:

          Pfirst-class=0
          Pspecial-delivery=100
          Plist=-30
          Pbulk=-60
          Pjunk=-100

      People writing mailing list exploders  are  encouraged
      to use "Precedence: list".  Older versions of sendmail
      (which discarded all error returns for negative prece-
      dences)  didn't  recognize  this  name,  giving  it  a
      default precedence of zero.  This  allows  list  main-
      tainers  to see error returns on both old and new ver-
      sions of sendmail.

   5.8.  V -- Configuration Version Level

           To provide compatibility with  old  configuration
      files,  the  V line has been added to define some very
      basic semantics of the configuration file.  These  are
      not  intended  to  be long term supports; rather, they
      describe compatibility features which will probably be
      removed in future releases.

           N.B.:  these  version  levels  have nothing to do
      with the version number on the files.  For example, as
      of this writing version 10 config files (specifically,
      8.10) used version level 9 configurations.










SMM:08-128         Sendmail Installation and Operation Guide


           "Old" configuration files are defined as  version
      level one.  Version level two files make the following
      changes:

       (1)   Host name canonification ($[ ... $]) appends  a
             dot  if  the name is recognized; this gives the
             config file a way of finding  out  if  anything
             matched.   (Actually, this just initializes the
             "host" map with the  "-a."   flag  --  you  can
             reset  it  to  anything you prefer by declaring
             the map explicitly.)

       (2)   Default  host  name  extension  is   consistent
             throughout  processing;  version level one con-
             figurations turned off domain  extension  (that
             is,  adding  the local domain name) during cer-
             tain points in processing.  Version  level  two
             configurations are expected to include a trail-
             ing dot to indicate that the  name  is  already
             canonical.

       (3)   Local  names  that  are  not aliases are passed
             through a new distinguished ruleset five;  this
             can  be  used  to  append  a local relay.  This
             behavior can  be  prevented  by  resolving  the
             local name with an initial `@'.  That is, some-
             thing that resolves to a  local  mailer  and  a
             user  name  of  "vikki"  will be passed through
             ruleset five, but a user name of "@vikki"  will
             have  the  `@'  stripped,  will  not  be passed
             through ruleset five,  but  will  otherwise  be
             treated  the  same  as  the prior example.  The
             expectation is  that  this  might  be  used  to
             implement  a  policy where mail sent to "vikki"
             was handled by a central hub, but mail sent  to
             "vikki@localhost" was delivered directly.

           Version  level three files allow # initiated com-
      ments on all lines.  Exceptions are backslash  escaped
      # marks and the $# syntax.

           Version  level four configurations are completely
      equivalent to level three for historical reasons.

           Version level five configuration files change the
      default  definition  of $w to be just the first compo-
      nent of the hostname.

           Version level six configuration files change many
      of  the local processing options (such as aliasing and
      matching the beginning of the address for `|'  charac-
      ters)  to  be  mailer  flags; this allows fine-grained
      control over the special local processing.  Level  six










Sendmail Installation and Operation Guide         SMM:08-129


      configuration  files  may  also use long option names.
      The ColonOkInAddr  option  (to  allow  colons  in  the
      local-part  of  addresses)  defaults on for lower num-
      bered  configuration  files;  the  configuration  file
      requires some additional intelligence to properly han-
      dle the RFC 822 group construct.

           Version level seven configuration files used  new
      option  names  to  replace old macros ($e became Smtp-
      GreetingMessage, $l became UnixFromLine, and $o became
      OperatorChars.   Also, prior to version seven, the F=q
      flag (use 250 instead of 252  return  value  for  SMTP
      VRFY commands) was assumed.

           Version  level eight configuration files allow $#
      on the left hand side of ruleset lines.

           Version  level  nine  configuration  files  allow
      parentheses  in rulesets, i.e. they are not treated as
      comments and hence removed.

           Version level ten configuration files allow queue
      group definitions.

           The  V line may have an optional /vendor to indi-
      cate that this configuration file  uses  modifications
      specific to a  particular  vendor[22].   You  may  use
      "/Berkeley"  to emphasize that this configuration file
      uses the Berkeley dialect of sendmail.

   5.9.  K -- Key File Declaration

           Special maps can be defined using the line:

          Kmapname mapclass arguments

      The mapname is the handle by which this map is  refer-
      enced  in  the  rewriting  rules.  The mapclass is the
      name of a type of map; these are compiled in to  send-
      mail.   The arguments are interpreted depending on the
      class; typically, there would  be  a  single  argument
      naming the file containing the map.

           Maps are referenced using the syntax:

          $( map key $@ arguments $: default $)
____________________
   [22]And  of  course,  vendors are encouraged to add them-
selves to the list of recognized vendors by editing the rou-
tine  setvendor  in  conf.c.   Please  send  e-mail to send-
mail@Sendmail.ORG to register your vendor dialect.












SMM:08-130         Sendmail Installation and Operation Guide


      where  either or both of the arguments or default por-
      tion may be omitted.  The $@ arguments may appear more
      than once.  The indicated key and arguments are passed
      to the appropriate mapping function.  If it returns  a
      value, it replaces the input.  If it does not return a
      value  and  the  default  is  specified,  the  default
      replaces   the   input.    Otherwise,   the  input  is
      unchanged.

           The arguments are passed to the map for arbitrary
      use.  Most map classes can interpolate these arguments
      into their values using the syntax "%n" (where n is  a
      digit)  to indicate the corresponding argument.  Argu-
      ment "%0" indicates the database  key.   For  example,
      the rule

          R$- ! $+       $: $(uucp $1 $@ $2 $: $2 @ $1 . UUCP $)

      Looks  up  the UUCP name in a (user defined) UUCP map;
      if not found it turns it into ".UUCP" form.  The data-
      base might contain records like:

          decvax         %1@%0.DEC.COM
          research       %1@%0.ATT.COM

      Note that default clauses never do this mapping.

           The  built-in map with both name and class "host"
      is the host name canonicalization lookup.   Thus,  the
      syntax:

          $(host hostname$)

      is equivalent to:

          $[hostname$]


           There are many defined classes.

      dbm       Database  lookups using the ndbm(3) library.
                Sendmail must be compiled with NDBM defined.

      btree     Database lookups using the  btree  interface
                to  the  Berkeley DB library.  Sendmail must
                be compiled with NEWDB defined.

      hash      Database lookups using the hash interface to
                the  Berkeley  DB library.  Sendmail must be
                compiled with NEWDB defined.

      nis       NIS lookups.  Sendmail must be compiled with
                NIS defined.










Sendmail Installation and Operation Guide         SMM:08-131


      nisplus   NIS+  lookups.   Sendmail  must  be compiled
                with NISPLUS defined.  The argument  is  the
                name  of  the  table to use for lookups, and
                the -k and -v flags may be used to  set  the
                key and value columns respectively.

      hesiod    Hesiod  lookups.   Sendmail must be compiled
                with HESIOD defined.

      ldap      LDAP X500 directory lookups.  Sendmail  must
                be  compiled  with LDAPMAP defined.  The map
                supports most of the standard arguments  and
                most  of  the  command line arguments of the
                ldapsearch program.  Note that, by  default,
                if  a  single query matches multiple values,
                only the first value will be returned unless
                the  -z  (value  separator) map flag is set.
                Also, the -1 map flag will treat a  multiple
                value return as if there were no matches.

      netinfo   NeXT NetInfo lookups.  Sendmail must be com-
                piled with NETINFO defined.

      text      Text file lookups.  The format of  the  text
                file  is  defined  by the -k (key field num-
                ber), -v (value field number), and -z (field
                delimiter) flags.

      ph        PH  query map.  Contributed and supported by
                Mark Roth, roth@uiuc.edu.  For more informa-
                tion,  consult  the  web  site  "http://www-
                dev.cites.uiuc.edu/sendmail/".

      nsd       nsd map for IRIX 6.5 and later.  Contributed
                and   supported   by   Bob   Mende  of  SGI,
                mende@sgi.com.

      stab      Internal symbol table lookups.  Used  inter-
                nally for aliasing.

      implicit  Really  should  be called "alias" -- this is
                used to get the default  lookups  for  alias
                files,  and  is  the  default if no class is
                specified for alias files.

      user      Looks up users using  getpwnam(3).   The  -v
                flag  can be used to specify the name of the
                field to return (although this  is  normally
                used only to check the existence of a user).

      host      Canonifies  host domain names.  Given a host
                name it calls the name server  to  find  the
                canonical name for that host.










SMM:08-132         Sendmail Installation and Operation Guide


      bestmx    Returns  the  best MX record for a host name
                given as the key.  The  current  machine  is
                always  preferred -- that is, if the current
                machine is one of the hosts listed as a low-
                est-preference  MX  record,  then it will be
                guaranteed to be returned.  This can be used
                to  find  out  if this machine is the target
                for an MX record, and mail can  be  accepted
                on  that  basis.   If  the -z flag is given,
                then all MX names are returned, separated by
                the given delimiter.

      dns       This  map  requires the option -R to specify
                the DNS resource record type to lookup.  The
                following  types  are  supported:  A,  AAAA,
                AFSDB, CNAME, MX, NS, PTR, SRV, and TXT.   A
                map  lookup  will  return  only  one record.
                Hence for some types, e.g., MX records,  the
                return  value  might  be a random element of
                the list  due  to  randomizing  in  the  DNS
                resolver.

      sequence  The  arguments on the `K' line are a list of
                maps; the resulting map searches  the  argu-
                ment  maps  in  order until it finds a match
                for the indicated key.  For example, if  the
                key definition is:

                    Kmap1 ...
                    Kmap2 ...
                    Kseqmap sequence map1 map2

                then  a lookup against "seqmap" first does a
                lookup  in  map1.   If  that  is  found,  it
                returns  immediately.   Otherwise,  the same
                key is used for map2.

      syslog    the  key  is  logged  via  syslogd(8).   The
                lookup returns the empty string.

      switch    Much like the "sequence" map except that the
                order of maps is determined by  the  service
                switch.   The  argument  is  the name of the
                service to be looked up; the values from the
                service  switch are appended to the map name
                to create new map names.  For example,  con-
                sider the key definition:

                    Kali switch aliases

                together with the service switch entry:

                    aliases        nis files










Sendmail Installation and Operation Guide         SMM:08-133


                This causes a query against the map "ali" to
                search maps named "ali.nis" and  "ali.files"
                in that order.

      dequote   Strip  double  quotes  (")  from a name.  It
                does not strip  backslashes,  and  will  not
                strip  quotes  if the resulting string would
                contain unscannable syntax (that  is,  basic
                errors  like unbalanced angle brackets; more
                sophisticated errors such as  unknown  hosts
                are  not  checked).   The  intent is for use
                when trying to accept mail from systems such
                as  DECnet  that  routinely quote odd syntax
                such as

                    "49ers::ubell"

                A typical usage is probably something like:

                    Kdequote dequote

                    ...

                    R$-            $: $(dequote $1 $)
                    R$- $+         $: $>3 $1 $2

                Care must be  taken  to  prevent  unexpected
                results; for example,

                    "|someprogram < input > output"

                will have quotes stripped, but the result is
                probably not what you had in  mind.   Fortu-
                nately these cases are rare.

      regex     The  map definition on the K line contains a
                regular expression.  Any key input  is  com-
                pared  to  that  expression  using the POSIX
                regular  expressions   routines   regcomp(),
                regerr(), and regexec().  Refer to the docu-
                mentation for those routines for more infor-
                mation  about  the regular expression match-
                ing.  No rewriting of the key is done if the
                -m  flag  is  used.   Without it, the key is
                discarded or if -s if used,  it  is  substi-
                tuted by the substring matches, delimited by
                $| or the string specified with the  the  -d
                flag.  The flags available for the map are















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                    -n  not
                    -f  case sensitive
                    -b  basic regular expressions (default is extended)
                    -s  substring match
                    -d  set the delimiter used for -s
                    -a  append string to key
                    -m  match only, do not replace/discard value
                    -D  perform no lookup in deferred delivery mode.

                The  -s flag can include an optional parame-
                ter which can be used  to  select  the  sub-
                strings  in  the  result of the lookup.  For
                example,

                    -s1,3,4

                Notes: to match a $ in a string, \$$ must be
                used.   If the pattern contains spaces, they
                must be replaced with the blank substitution
                character, unless it is space itself.

      program   The arguments on the K line are the pathname
                to a program and any initial  parameters  to
                be  passed.  When the map is called, the key
                is added to the initial parameters  and  the
                program is invoked as the default user/group
                id.  The first line of  standard  output  is
                returned  as  the value of the lookup.  This
                has many potential  security  problems,  and
                has  terrible performance; it should be used
                only when absolutely necessary.

      macro     Set or clear a macro value.  To set a macro,
                pass  the value as the first argument in the
                map lookup.  To clear a macro, do  not  pass
                an  argument  in  the  map  lookup.  The map
                always returns the empty string.  Example of
                typical usage include:

                    Kstorage macro

                    ...

                    # set macro ${MyMacro} to the ruleset match
                    R$+ $: $(storage {MyMacro} $@ $1 $) $1
                    # set macro ${MyMacro} to an empty string
                    R$* $: $(storage {MyMacro} $@ $) $1
                    # clear macro ${MyMacro}
                    R$- $: $(storage {MyMacro} $) $1


      arith     Perform  simple  arithmetic operations.  The
                operation is given as key, currently  +,  -,










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                *, /, %, |, & (bitwise OR, AND), l (for less
                than), =, and r (for random) are  supported.
                The  two  operands  are  given as arguments.
                The lookup returns the result of the  compu-
                tation, i.e., TRUE or FALSE for comparisons,
                integer values otherwise.   The  r  operator
                returns  a  pseudo-random number whose value
                lies between the first  and  second  operand
                (which  requires  that  the first operand is
                smaller than the second).  All options which
                are possible for maps are ignored.  A simple
                example is:

                    Kcomp arith

                    ...

                    Scheck_etrn
                    R$* $: $(comp l $@ $&{load_avg} $@ 7 $) $1
                    RFALSE$# error ...


      socket    The socket map uses a  simple  request/reply
                protocol  over TCP or UNIX domain sockets to
                query an external server.  Both requests and
                replies  are  text based and encoded as net-
                strings,  i.e.,  a  string   "hello   there"
                becomes:

                    11:hello there,

                Note:  neither requests nor replies end with
                CRLF.

                The request consists  of  the  database  map
                name and the lookup key separated by a space
                character:


                    <mapname> ' ' <key>


                The server responds with a status  indicator
                and the result (if any):


                    <status> ' ' <result>


                The status indicator specifies the result of
                the lookup operation itself and  is  one  of
                the following upper case words:











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                    OK       the key was found, result contains the looked up value
                    NOTFOUND the key was not found, the result is empty
                    TEMP     a temporary failure occured
                    TIMEOUT  a timeout occured on the server side
                    PERM     a permanent failure occured


                In  case  of errors (status TEMP, TIMEOUT or
                PERM)  the  result  field  may  contain   an
                explanatory  message.  However, the explana-
                tory message is  not  used  any  further  by
                sendmail.

                Example replies:

                    31:OK resolved.address@example.com,



                    56:OK error:550 5.7.1 User does not accept mail from sender,


                in case of successful lookups, or:

                    8:NOTFOUND,


                in case the key was not found, or:

                    55:TEMP this text explains that we had a temporary failure,


                in case of a temporary map lookup failure.

                The  socket map uses the same syntax as mil-
                ters (see Section "X -- Mail Filter (Milter)
                Definitions")  to  specify  the  remote end-
                point, e.g.,

                    Ksocket mySocketMap inet:12345@127.0.0.1


                If multiple  socket  maps  define  the  same
                remote  endpoint,  they  will share a single
                connection to this endpoint.

           Most  of  these  accept  as  arguments  the  same
      optional  flags  and a filename (or a mapname for NIS;
      the filename is the root of the database path, so that
      ".db"  or  some  other  extension  appropriate for the
      database type will be added to get the actual database
      name).  Known flags are:











Sendmail Installation and Operation Guide         SMM:08-137


      -o        Indicates  that this map is optional -- that
                is, if it cannot be opened, no error is pro-
                duced,  and  sendmail  will behave as if the
                map existed but was empty.

      -N, -O    If neither -N or -O are specified,  sendmail
                uses an adaptive algorithm to decide whether
                or not to look for null bytes on the end  of
                keys.  It starts by trying both; if it finds
                any key with a  null  byte  it  never  tries
                again  without  a  null byte and vice versa.
                If -N is specified it never tries without  a
                null  byte  and  if -O is specified it never
                tries with a  null  byte.   Setting  one  of
                these can speed matches but are never neces-
                sary.  If both  -N  and  -O  are  specified,
                sendmail  will  never try any matches at all
                -- that is, everything will appear to fail.

      -ax       Append the string x on  successful  matches.
                For  example, the default host map appends a
                dot on successful matches.

      -Tx       Append the string x on  temporary  failures.
                For  example,  x  would be appended if a DNS
                lookup returned "server failed"  or  an  NIS
                lookup  could not locate a server.  See also
                the -t flag.

      -f        Do not fold upper to lower case before look-
                ing up the key.

      -m        Match  only  (without  replacing the value).
                If you only care about the  existence  of  a
                key  and  not  the  value (as you might when
                searching the  NIS  map  "hosts.byname"  for
                example),  this  flag  prevents the map from
                substituting the  value.   However,  The  -a
                argument  is  still appended on a match, and
                the default is  still  taken  if  the  match
                fails.

      -kkeycol  The  key  column  name  (for NIS+) or number
                (for text lookups).  For LDAP maps  this  is
                an   LDAP  filter  string  in  which  %s  is
                replaced with the literal  contents  of  the
                lookup  key and %0 is replaced with the LDAP
                escaped contents of the lookup key according
                to  RFC  2254.  If the flag -K is used, then
                %1 through %9 are  replaced  with  the  LDAP
                escaped  contents of the arguments specified
                in the map lookup.











SMM:08-138         Sendmail Installation and Operation Guide


      -vvalcol  The value column name (for NIS+)  or  number
                (for  text  lookups).  For LDAP maps this is
                the name of one or  more  attributes  to  be
                returned;  multiple  attributes can be sepa-
                rated by  commas.   If  not  specified,  all
                attributes   found  in  the  match  will  be
                returned.  The attributes  listed  can  also
                include  a  type and one or more objectClass
                values for matching as described in the LDAP
                section.

      -zdelim   The column delimiter (for text lookups).  It
                can be a single character or one of the spe-
                cial  strings  "\n" or "\t" to indicate new-
                line  or  tab  respectively.    If   omitted
                entirely,   the   column  separator  is  any
                sequence of white space.  For LDAP maps this
                is the separator character to combine multi-
                ple values into a single return string.   If
                not  set,  the  LDAP lookup will only return
                the first match found.  For DNS maps this is
                the  separator character at which the result
                of a query is cut off if is too long.

      -t        Normally, when a map attempts to do a lookup
                and   the   server   fails  (e.g.,  sendmail
                couldn't contact any name  server;  this  is
                not  the same as an entry not being found in
                the map), the  message  being  processed  is
                queued  for  future processing.  The -t flag
                turns off this behavior, letting the  tempo-
                rary  failure (server down) act as though it
                were a permanent failure (entry not  found).
                It  is  particularly useful for DNS lookups,
                where  someone  else's  misconfigured   name
                server  can  cause problems on your machine.
                However, care must be taken to  ensure  that
                you don't bounce mail that would be resolved
                correctly if  you  tried  again.   A  common
                strategy is to forward such mail to another,
                possibly better connected, mail server.

      -D        Perform no lookup in deferred delivery mode.
                This  flag  is  set  by default for the host
                map.

      -Sspacesub
                The character to use to replace space  char-
                acters  after  a successful map lookup (esp.
                useful for regex and syslog maps).

      -sspacesub
                For the dequote map only, the  character  to










Sendmail Installation and Operation Guide         SMM:08-139


                use to replace space characters after a suc-
                cessful dequote.

      -q        Don't dequote the key before lookup.

      -Llevel   For the syslog map only,  it  specifies  the
                level to use for the syslog call.

      -A        When  rebuilding  an alias file, the -A flag
                causes duplicate entries in the text version
                to be merged.  For example, two entries:

                    list:    user1, user2
                    list:    user3

                would  be treated as though it were the sin-
                gle entry

                    list:    user1, user2, user3

                in the presence of the -A flag.

           Some additional flags are available for the  host
      and dns maps:

      -d        delay: specify the resolver's retransmission
                time interval (in seconds).

      -r        retry:  specify  the  number  of  times   to
                retransmit a resolver query.

           The dns map has another flag:

      -B        basedomain:  specify a domain that is always
                appended to queries.

           The following additional flags are present in the
      ldap map only:

      -R        Do  not auto chase referrals.  sendmail must
                be compiled  with  -DLDAP_REFERRALS  to  use
                this flag.

      -n        Retrieve attribute names only.

      -Vsep     Retrieve  both attributes name and value(s),
                separated by sep.

      -rderef   Set the alias dereference option to  one  of
                never, always, search, or find.

      -sscope   Set  search  scope  to one of base, one (one
                level), or sub (subtree).










SMM:08-140         Sendmail Installation and Operation Guide


      -hhost    LDAP server hostname.  Some  LDAP  libraries
                allow  you  to specify multiple, space-sepa-
                rated hosts for  redundancy.   In  addition,
                each  of the hosts listed can be followed by
                a colon and a port number  to  override  the
                default LDAP port.

      -pport    LDAP service port.

      -H LDAPURI
                Use the specified LDAP URI instead of speci-
                fying the hostname and port separately  with
                the  the -h and -p options shown above.  For
                example,

                    -h server.example.com -p 389 -b dc=example,dc=com

                is equivalent to

                    -H ldap://server.example.com:389 -b dc=example,dc=com

                If the LDAP library supports  it,  the  LDAP
                URI  format  however  can  also request LDAP
                over  SSL  by  using  ldaps://  instead   of
                ldap://.  For example:

                    O LDAPDefaultSpec=-H ldaps://ldap.example.com -b dc=example,dc=com

                Similarly,  if the LDAP library supports it,
                It can also be used to specify a UNIX domain
                socket using ldapi://:

                    O LDAPDefaultSpec=-H ldapi://socketfile -b dc=example,dc=com


      -bbase    LDAP search base.

      -ltimelimit
                Time limit for LDAP queries.

      -Zsizelimit
                Size  (number  of matches) limit for LDAP or
                DNS queries.

      -ddistinguished_name
                The distinguished name to use  to  login  to
                the LDAP server.

      -Mmethod  The  method  to  authenticate  to  the  LDAP
                server.  Should be  one  of  LDAP_AUTH_NONE,
                LDAP_AUTH_SIMPLE, or LDAP_AUTH_KRBV4.












Sendmail Installation and Operation Guide         SMM:08-141


      -Ppasswordfile
                The  file  containing the secret key for the
                LDAP_AUTH_SIMPLE  authentication  method  or
                the  name  of  the  Kerberos ticket file for
                LDAP_AUTH_KRBV4.

      -1        Force LDAP searches to  only  succeed  if  a
                single  match  is found.  If multiple values
                are found, the search is treated  as  if  no
                match was found.

      -wversion Set  the  LDAP  API/protocol version to use.
                The  default  depends  on  the  LDAP  client
                libraries  in  use.   For example, -w 3 will
                cause sendmail to use LDAPv3  when  communi-
                cating with the LDAP server.

      -K        Treat  the LDAP search key as multi-argument
                and replace %1 through %9 in  the  key  with
                the  LDAP  escaped  contents  of  the lookup
                arguments specified in the map lookup.

           The dbm map appends the strings ".pag" and ".dir"
      to  the given filename; the hash and btree maps append
      ".db".  For example, the map specification

          Kuucp dbm -o -N /etc/mail/uucpmap

      specifies an optional map named "uucp" of class "dbm";
      it  always  has null bytes at the end of every string,
      and      the      data       is       located       in
      /etc/mail/uucpmap.{dir,pag}.

           The  program  makemap(8) can be used to build any
      of the three database-oriented  maps.   It  takes  the
      following flags:

      -f        Do not fold upper to lower case in the map.

      -N        Include null bytes in keys.

      -o        Append to an existing (old) file.

      -r        Allow  replacement  of  existing  keys; nor-
                mally, re-inserting an existing  key  is  an
                error.

      -v        Print what is happening.

      The  sendmail  daemon does not have to be restarted to
      read the new maps as long as you change them in place;
      file  locking  is  used so that the maps won't be read
      while they are being updated.










SMM:08-142         Sendmail Installation and Operation Guide


           New classes can be added in the routine setupmaps
      in file conf.c.

   5.10.  Q -- Queue Group Declaration

           In  addition  to the option QueueDirectory, queue
      groups can be declared that define a (group of)  queue
      directories  under  a  common  name.  The syntax is as
      follows:

          Qname {, field=value}+

      where name is the symbolic name  of  the  queue  group
      under which it can be referenced in various places and
      the "field=value" pairs define attributes of the queue
      group.   The  name  must  only consist of alphanumeric
      characters.  Fields are:

      Flags     Flags for this queue group.

      Nice      The nice(2) increment for the  queue  group.
                This value must be greater or equal zero.

      Interval  The time between two queue runs.

      Path      The queue directory of the group (required).

      Runners   The  number  of  parallel runners processing
                the queue.  Note that F=f  must  be  set  if
                this value is greater than one.

      Jobs      The  maximum number of jobs (messages deliv-
                ered) per queue run.

      recipients
                The maximum number of recipients  per  enve-
                lope.   Envelopes with more than this number
                of recipients will be  split  into  multiple
                envelopes  in the same queue directory.  The
                default value 0 means no limit.

      Only the first character of the field name is checked.

           By default, a queue group named mqueue is defined
      that  uses  the  value of the QueueDirectory option as
      path.  Notice: all  paths  that  are  used  for  queue
      groups   must  be  subdirectories  of  QueueDirectory.
      Since they can be symbolic links, this  isn't  a  real
      restriction,  If  QueueDirectory uses a wildcard, then
      the directory one level up is considered the  ``base''
      directory  which  all  other  queue  directories  must
      share.  Please make sure that the queue directories do
      not overlap, e.g., do not specify










Sendmail Installation and Operation Guide         SMM:08-143


          O QueueDirectory=/var/spool/mqueue/*
          Qone, P=/var/spool/mqueue/dir1
          Qtwo, P=/var/spool/mqueue/dir2

      because  this  also  includes "dir1" and "dir2" in the
      default queue group.  However,

          O QueueDirectory=/var/spool/mqueue/main*
          Qone, P=/var/spool/mqueue/dir
          Qtwo, P=/var/spool/mqueue/other*

      is a valid queue group specification.

           Options listed in the ``Flags'' field can be used
      to  modify  the  behavior of a queue group.  The ``f''
      flag must be set if multiple queue  runners  are  sup-
      posed to work on the entries in a queue group.  Other-
      wise  sendmail  will  work  on  the  entries  strictly
      sequentially.

           The  ``Interval''  field  sets  the  time between
      queue runs.  If no queue group  specific  interval  is
      set, then the parameter of the -q option from the com-
      mand line is used.

           To control the  overall  number  of  concurrently
      active  queue  runners the option MaxQueueChildren can
      be set.  This limits the number of processes used  for
      running  the queues to MaxQueueChildren, though at any
      one time fewer processes may be active as a result  of
      queue options, completed queue runs, system load, etc.

           The  maximum number of queue runners for an indi-
      vidual queue group can be controlled via  the  Runners
      option.  If set to 0, entries in the queue will not be
      processed, which is  useful  to  ``quarantine''  queue
      files.  The number of runners per queue group may also
      be  set  with  the  option  MaxRunnersPerQueue,  which
      applies to queue groups that have no individual limit.
      That is, the default  value  for  Runners  is  MaxRun-
      nersPerQueue if set, otherwise 1.

           The  field  Jobs  describes the maximum number of
      jobs (messages delivered) per queue run, which is  the
      queue group specific value of MaxQueueRunSize.

           Notice: queue groups should be declared after all
      queue related options  have  been  set  because  queue
      groups  take their defaults from those options.  If an
      option is set after a  queue  group  declaration,  the
      values  of  options  in the queue group are set to the
      defaults of sendmail unless explicitly set in the dec-
      laration.










SMM:08-144         Sendmail Installation and Operation Guide


           Each  envelope is assigned to a queue group based
      on the algorithm described in section  ``Queue  Groups
      and Queue Directories''.

   5.11.  X -- Mail Filter (Milter) Definitions

           The sendmail Mail Filter API (Milter) is designed
      to allow third-party programs access to mail  messages
      as  they  are being processed in order to filter meta-
      information and content.  They  are  declared  in  the
      configuration file as:

          Xname {, field=value}*

      where  name is the name of the filter (used internally
      only) and the "field=name" pairs define attributes  of
      the filter.  Also see the documentation for the Input-
      MailFilters option for more information.

           Fields are:

          Socket    The socket specification
          Flags     Special flags for this filter
          Timeouts  Timeouts for this filter

      Only the first character of the field name is  checked
      (it's case-sensitive).

           The  socket specification is one of the following
      forms:

          S=inet: port @ host


          S=inet6: port @ host


          S=local: path

      The first two describe an IPv4 or IPv6 socket  listen-
      ing  on  a certain port at a given host or IP address.
      The  final  form  describes  a  named  socket  on  the
      filesystem at the given path.

           The  following  flags  may  be  set in the filter
      description.

      R   Reject connection if filter unavailable.

      T   Temporary fail connection if filter unavailable.

           If neither F=R nor F=T is specified, the  message
      is passed through sendmail in case of filter errors as










Sendmail Installation and Operation Guide         SMM:08-145


      if the failing filters were not present.

           The timeouts can be set  using  the  four  fields
      inside of the T= equate:

      C   Timeout  for connecting to a filter.  If set to 0,
          the system's connect() timeout will be used.

      S   Timeout for sending information from the MTA to  a
          filter.

      R   Timeout for reading reply from the filter.

      E   Overall  timeout between sending end-of-message to
          filter and waiting for the final acknowledgment.

           Note the separator between each timeout field  is
      a   ';'.    The  default  values  (if  not  set)  are:
      T=C:5m;S:10s;R:10s;E:5m where s is seconds  and  m  is
      minutes.

           Examples:

          Xfilter1, S=local:/var/run/f1.sock, F=R
          Xfilter2, S=inet6:999@localhost, F=T, T=S:1s;R:1s;E:5m
          Xfilter3, S=inet:3333@localhost, T=C:2m


   5.12.  The User Database

           The  user  database  is  deprecated  in  favor of
      ``virtusertable'' and ``genericstable''  as  explained
      in the file cf/README.  If you have a version of send-
      mail with the user database package compiled  in,  the
      handling  of  sender  and recipient addresses is modi-
      fied.

           The location of this database is controlled  with
      the UserDatabaseSpec option.

      5.12.1.  Structure of the user database

              The  database is a sorted (BTree-based) struc-
         ture.  User records are stored with the key:

             user-name:field-name

         The  sorted  database  format  ensures  that   user
         records  are  clustered together.  Meta-information
         is always stored with a leading colon.

              Field names define both the syntax and  seman-
         tics of the value.  Defined fields include:










SMM:08-146         Sendmail Installation and Operation Guide


         maildrop  The   delivery  address  for  this  user.
                   There may  be  multiple  values  of  this
                   record.   In  particular,  mailing  lists
                   will have one maildrop  record  for  each
                   user on the list.

         mailname  The outgoing mailname for this user.  For
                   each outgoing name, there  should  be  an
                   appropriate maildrop record for that name
                   to   allow   return   mail.    See   also
                   :default:mailname.

         mailsender
                   Changes  any mail sent to this address to
                   have the indicated envelope sender.  This
                   is  intended  for mailing lists, and will
                   normally be the name  of  an  appropriate
                   -request  address.  It is very similar to
                   the owner-list syntax in the alias file.

         fullname  The full name of the user.

         office-address
                   The office address for this user.

         office-phone
                   The office phone number for this user.

         office-fax
                   The office FAX number for this user.

         home-address
                   The home address for this user.

         home-phone
                   The home phone number for this user.

         home-fax  The home FAX number for this user.

         project   A (short) description of the project this
                   person  is  affiliated with.  In the Uni-
                   versity this is often just  the  name  of
                   their graduate advisor.

         plan      A  pointer  to  a  file  from  which plan
                   information can be gathered.

              As of this writing, only a few of these fields
         are  actually  being used by sendmail: maildrop and
         mailname.  A finger program  that  uses  the  other
         fields is planned.












Sendmail Installation and Operation Guide         SMM:08-147


      5.12.2.  User database semantics

              When  the rewriting rules submit an address to
         the local mailer, the user name is  passed  through
         the  alias  file.   If no alias is found (or if the
         alias points back to the same  address),  the  name
         (with  ":maildrop"  appended) is then used as a key
         in the user database.  If no match  occurs  (or  if
         the  maildrop points at the same address), forward-
         ing is tried.

              If the first token of the user  name  returned
         by  ruleset  0  is  an  "@" sign, the user database
         lookup is skipped.  The intent  is  that  the  user
         database  will act as a set of defaults for a clus-
         ter (in our case, the Computer  Science  Division);
         mail sent to a specific machine should ignore these
         defaults.

              When mail is sent, the  name  of  the  sending
         user  is  looked  up in the database.  If that user
         has a "mailname" record, the value of  that  record
         is  used  as  their  outgoing name.  For example, I
         might have a record:

             eric:mailnameEric.Allman@CS.Berkeley.EDU

         This would cause my outgoing mail  to  be  sent  as
         Eric.Allman.

              If  a "maildrop" is found for the user, but no
         corresponding "mailname" record exists, the  record
         ":default:mailname" is consulted.  If present, this
         is the name of a host to override the  local  host.
         For  example,  in  our  case  we  would  set  it to
         "CS.Berkeley.EDU".  The effect is that anyone known
         in the database gets their outgoing mail stamped as
         "user@CS.Berkeley.EDU", but people  not  listed  in
         the database use the local hostname.

      5.12.3.  Creating the database[23]

              The user database is built from  a  text  file
         using  the  makemap utility (in the distribution in
         the makemap subdirectory).   The  text  file  is  a
         series  of  lines  corresponding to userdb records;
____________________
   [23]These instructions are known to be incomplete.  Other
features are available which provide similar  functionality,
e.g.,  virtual  hosting  and  mapping local addresses into a
generic form as explained in cf/README.












SMM:08-148         Sendmail Installation and Operation Guide


         each line has a key and a value separated by  white
         space.   The  key is always in the format described
         above -- for example:

             eric:maildrop

         This file is normally installed in a system  direc-
         tory;    for    example,   it   might   be   called
         /etc/mail/userdb.  To make the database version  of
         the map, run the program:

             makemap btree /etc/mail/userdb < /etc/mail/userdb

         Then  create  a  config  file  that uses this.  For
         example, using the V8 M4 configuration, include the
         following line in your .mc file:

             define(`confUSERDB_SPEC', /etc/mail/userdb)


6.  OTHER CONFIGURATION

        There  are  some  configuration  changes that can be
   made by recompiling  sendmail.   This  section  describes
   what  changes  can be made and what has to be modified to
   make them.  In most  cases  this  should  be  unnecessary
   unless you are porting sendmail to a new environment.

   6.1.  Parameters in devtools/OS/$oscf

           These  parameters  are  intended  to describe the
      compilation environment, not site policy,  and  should
      normally be defined in the operating system configura-
      tion file.  This section needs a complete rewrite.

      NDBM      If set, the new version of the  DBM  library
                that allows multiple databases will be used.
                If neither NDBM nor NEWDB are  set,  a  much
                less  efficient  method  of  alias lookup is
                used.

      NEWDB     If set, use the new  database  package  from
                Berkeley  (from  4.4BSD).   This  package is
                substantially faster than DBM or  NDBM.   If
                NEWDB  and  NDBM are both set, sendmail will
                read DBM files,  but  will  create  and  use
                NEWDB files.

      NIS       Include  support  for  NIS.  If set together
                with both NEWDB and NDBM, sendmail will cre-
                ate  both DBM and NEWDB files if and only if
                an alias file includes the substring  "/yp/"
                in   the   name.    This   is  intended  for










Sendmail Installation and Operation Guide         SMM:08-149


                compatibility with Sun Microsystems' mkalias
                program used on YP masters.

      NISPLUS   Compile in support for NIS+.

      NETINFO   Compile  in  support  for NetInfo (NeXT sta-
                tions).

      LDAPMAP   Compile in support for  LDAP  X500  queries.
                Requires  libldap and liblber from the Umich
                LDAP  3.2  or  3.3  release  or   equivalent
                libraries  for  other LDAP libraries such as
                OpenLDAP.

      HESIOD    Compile in support for Hesiod.

      MAP_NSD   Compile in support for IRIX NSD lookups.

      MAP_REGEX Compile in support  for  regular  expression
                matching.

      DNSMAP    Compile  in  support  for DNS map lookups in
                the sendmail.cf file.

      PH_MAP    Compile in support for ph lookups.

      SASL      Compile in support for SASL, a required com-
                ponent for SMTP Authentication support.

      STARTTLS  Compile in support for STARTTLS.

      EGD       Compile  in support for the "Entropy Gather-
                ing Daemon" to provide  better  random  data
                for TLS.

      TCPWRAPPERS
                Compile in support for TCP Wrappers.

      _PATH_SENDMAILCF
                The pathname of the sendmail.cf file.

      _PATH_SENDMAILPID
                The pathname of the sendmail.pid file.

      SM_CONF_SHM
                Compile  in  support  for shared memory, see
                section about "/var/spool/mqueue".

      MILTER    Compile in support for  contacting  external
                mail filters built with the Milter API.

           There are also several compilation flags to indi-
      cate the environment such as "_AIX3" and "_SCO_unix_".










SMM:08-150         Sendmail Installation and Operation Guide


      See  the  sendmail/README file for the latest scoop on
      these flags.

   6.2.  Parameters in sendmail/conf.h

           Parameters and compilation options are defined in
      conf.h.   Most  of these need not normally be tweaked;
      common parameters are all  in  sendmail.cf.   However,
      the  sizes  of  certain  primitive  vectors, etc., are
      included in this  file.   The  numbers  following  the
      parameters are their default value.

           This  document is not the best source of informa-
      tion for compilation flags  in  conf.h  --  see  send-
      mail/README or sendmail/conf.h itself.

      MAXLINE [2048]
                  The maximum line length of any input line.
                  If message lines exceed this  length  they
                  will  still  be  processed correctly; how-
                  ever,  header  lines,  configuration  file
                  lines,  alias lines, etc., must fit within
                  this limit.

      MAXNAME [256]
                  The maximum length of any name, such as  a
                  host or a user name.

      MAXPV [256] The  maximum  number  of parameters to any
                  mailer.  This limits the number of recipi-
                  ents  that  may  be passed in one transac-
                  tion.  It can be set to any arbitrary num-
                  ber  above  about  10, since sendmail will
                  break up a delivery into  smaller  batches
                  as  needed.   A  higher  number may reduce
                  load on your system, however.

      MAXQUEUEGROUPS [50]
                  The maximum number of queue groups.

      MAXATOM [1000]
                  The maximum number of atoms (tokens) in  a
                  single  address.  For example, the address
                  "eric@CS.Berkeley.EDU" is seven atoms.

      MAXMAILERS [25]
                  The maximum number of mailers that may  be
                  defined  in  the configuration file.  This
                  value is defined in include/sendmail/send-
                  mail.h.

      MAXRWSETS [200]
                  The  maximum number of rewriting sets that










Sendmail Installation and Operation Guide         SMM:08-151


                  may be defined.  The first half  of  these
                  are  reserved  for  numeric  specification
                  (e.g., ``S92''), while the upper half  are
                  reserved    for    auto-numbering   (e.g.,
                  ``Sfoo'').  Thus, with a value of  200  an
                  attempt  to  use ``S99'' will succeed, but
                  ``S100'' will fail.

      MAXPRIORITIES [25]
                  The  maximum  number  of  values  for  the
                  "Precedence:"  field  that  may be defined
                  (using the P line in sendmail.cf).

      MAXUSERENVIRON [100]
                  The maximum number of items  in  the  user
                  environment  that will be passed to subor-
                  dinate mailers.

      MAXMXHOSTS [100]
                  The maximum number of MX records  we  will
                  accept for any single host.

      MAXMAPSTACK [12]
                  The  maximum  number  of  maps that may be
                  "stacked" in a sequence class map.

      MAXMIMEARGS [20]
                  The maximum number of arguments in a  MIME
                  Content-Type: header; additional arguments
                  will be ignored.

      MAXMIMENESTING [20]
                  The maximum depth to which  MIME  messages
                  may  be nested (that is, nested Message or
                  Multipart documents; this does  not  limit
                  the  number of components in a single Mul-
                  tipart document).

      MAXDAEMONS [10]
                  The maximum  number  of  sockets  sendmail
                  will  open  for  accepting  connections on
                  different ports.

      MAXMACNAMELEN [25]
                  The maximum length of a macro name.

      A number of other compilation  options  exist.   These
      specify  whether  or  not specific code should be com-
      piled in.  Ones marked with * are 0/1 valued.

      NETINET*    If set, support for Internet protocol net-
                  working is compiled in.  Previous versions
                  of sendmail referred to  this  as  DAEMON;










SMM:08-152         Sendmail Installation and Operation Guide


                  this old usage is now incorrect.  Defaults
                  on; turn it off in the  Makefile  if  your
                  system doesn't support the Internet proto-
                  cols.

      NETINET6*   If set, support  for  IPv6  networking  is
                  compiled   in.    It  must  be  separately
                  enabled by adding  DaemonPortOptions  set-
                  tings.

      NETISO*     If  set, support for ISO protocol network-
                  ing is compiled in (it may be  appropriate
                  to #define this in the Makefile instead of
                  conf.h).

      NETUNIX*    If set, support for UNIX domain sockets is
                  compiled  in.   This  is  used for control
                  socket support.

      LOG         If set, the syslog routine in use at  some
                  sites  is  used.   This  makes an informa-
                  tional log record for  each  message  pro-
                  cessed,  and  makes  a higher priority log
                  record   for   internal   system   errors.
                  STRONGLY  RECOMMENDED  --  if  you want no
                  logging, turn it off in the  configuration
                  file.

      MATCHGECOS* Compile  in  the code to do ``fuzzy match-
                  ing'' on the GECOS field  in  /etc/passwd.
                  This  also  requires  that  the MatchGECOS
                  option be turned on.

      NAMED_BIND* Compile in code to use the Berkeley Inter-
                  net  Name  Domain (BIND) server to resolve
                  TCP/IP host names.

      NOTUNIX     If you are using a non-UNIX  mail  format,
                  you  can set this flag to turn off special
                  processing of UNIX-style "From " lines.

      USERDB*     Include  the  experimental  Berkeley  user
                  information database package.  This adds a
                  new level of local name expansion  between
                  aliasing and forwarding.  It also uses the
                  NEWDB package.  This may change in  future
                  releases.

      The  following  options are normally turned on in per-
      operating-system clauses in conf.h.

      IDENTPROTO* Compile in the IDENT protocol  as  defined
                  in  RFC  1413.   This  defaults on for all










Sendmail Installation and Operation Guide         SMM:08-153


                  systems except  Ultrix,  which  apparently
                  has the interesting "feature" that when it
                  receives a "host unreachable"  message  it
                  closes  all open connections to that host.
                  Since some  firewall  gateways  send  this
                  error code when you access an unauthorized
                  port (such as 113, used by IDENT),  Ultrix
                  cannot receive email from such hosts.

      SYSTEM5     Set  all  of  the  compilation  parameters
                  appropriate for System V.

      HASFLOCK*   Use Berkeley-style flock instead of System
                  V  lockf  to  do file locking.  Due to the
                  highly unusual semantics of  locks  across
                  forks in lockf, this should always be used
                  if at all possible.

      HASINITGROUPS
                  Set this if  your  system  has  the  init-
                  groups()  call (if you have multiple group
                  support).  This is the default if  SYSTEM5
                  is not defined or if you are on HPUX.

      HASUNAME    Set  this  if you have the uname(2) system
                  call (or corresponding  library  routine).
                  Set by default if SYSTEM5 is set.

      HASGETDTABLESIZE
                  Set  this if you have the getdtablesize(2)
                  system call.

      HASWAITPID  Set this if  you  have  the  haswaitpid(2)
                  system call.

      FAST_PID_RECYCLE
                  Set this if your system can possibly reuse
                  the same pid in the same second of time.

      SFS_TYPE    The mechanism that can be used to get file
                  system  capacity  information.  The values
                  can be one of SFS_USTAT (use the  ustat(2)
                  syscall), SFS_4ARGS (use the four argument
                  statfs(2) syscall), SFS_VFS (use  the  two
                  argument   statfs(2)   syscall   including
                  <sys/vfs.h>), SFS_MOUNT (use the two argu-
                  ment     statfs(2)    syscall    including
                  <sys/mount.h>), SFS_STATFS  (use  the  two
                  argument   statfs(2)   syscall   including
                  <sys/statfs.h>), SFS_STATVFS (use the  two
                  argument   statfs(2)   syscall   including
                  <sys/statvfs.h>), or SFS_NONE (no  way  to
                  get this information).










SMM:08-154         Sendmail Installation and Operation Guide


      LA_TYPE     The   load   average  type.   Details  are
                  described below.

      The are several built-in ways of  computing  the  load
      average.   Sendmail tries to auto-configure them based
      on imperfect guesses; you can select one using the  cc
      option -DLA_TYPE=type, where type is:

      LA_INT      The  kernel stores the load average in the
                  kernel as an array of long integers.   The
                  actual  values  are  scaled  by  a  factor
                  FSCALE (default 256).

      LA_SHORT    The kernel stores the load average in  the
                  kernel as an array of short integers.  The
                  actual  values  are  scaled  by  a  factor
                  FSCALE (default 256).

      LA_FLOAT    The  kernel stores the load average in the
                  kernel as an  array  of  double  precision
                  floats.

      LA_MACH     Use MACH-style load averages.

      LA_SUBR     Call  the  getloadavg  routine  to get the
                  load average as an array of doubles.

      LA_ZERO     Always return zero as  the  load  average.
                  This is the fallback case.

      If  type  LA_INT,  LA_SHORT, or LA_FLOAT is specified,
      you may also need to specify _PATH_UNIX (the  path  to
      your  system  binary)  and LA_AVENRUN (the name of the
      variable containing the load average  in  the  kernel;
      usually "_avenrun" or "avenrun").

   6.3.  Configuration in sendmail/conf.c

           The following changes can be made in conf.c.

      6.3.1.  Built-in Header Semantics

              Not  all  header  semantics are defined in the
         configuration file.  Header lines that should  only
         be  included  by  certain mailers (as well as other
         more obscure semantics) must be  specified  in  the
         HdrInfo  table  in conf.c.  This table contains the
         header name (which should be in all lower case) and
         a  set  of  header control flags (described below),
         The flags are:

         H_ACHECK    Normally when the check is made to  see
                     if  a  header line is compatible with a










Sendmail Installation and Operation Guide         SMM:08-155


                     mailer, sendmail  will  not  delete  an
                     existing  line.   If  this flag is set,
                     sendmail  will  delete  even   existing
                     header  lines.  That is, if this bit is
                     set and the mailer does not  have  flag
                     bits   set   that  intersect  with  the
                     required mailer  flags  in  the  header
                     definition  in  sendmail.cf, the header
                     line is always deleted.

         H_EOH       If this header field is set,  treat  it
                     like a blank line, i.e., it will signal
                     the end of the header and the beginning
                     of the message text.

         H_FORCE     Add  this  header  entry  even  if  one
                     existed in the message  before.   If  a
                     header  entry  does  not  have this bit
                     set,  sendmail  will  not  add  another
                     header  line  if  a header line of this
                     name already existed.  This would  nor-
                     mally  be  used to stamp the message by
                     everyone who handled it.

         H_TRACE     If set, this  is  a  timestamp  (trace)
                     field.   If  the number of trace fields
                     in a message exceeds  a  preset  amount
                     the  message is returned on the assump-
                     tion that it has an aliasing loop.

         H_RCPT      If set, this field  contains  recipient
                     addresses.  This is used by the -t flag
                     to determine who to send to when it  is
                     collecting recipients from the message.

         H_FROM      This  flag  indicates  that  this field
                     specifies a sender.  The order of these
                     fields  in  the HdrInfo table specifies
                     sendmail's preference for  which  field
                     to return error messages to.

         H_ERRORSTO  Addresses in this header should receive
                     error messages.

         H_CTE       This  header  is  a   Content-Transfer-
                     Encoding header.

         H_CTYPE     This header is a Content-Type header.

         H_STRIPVAL  Strip  the  value  from the header (for
                     Bcc:).












SMM:08-156         Sendmail Installation and Operation Guide


         Let's look at a sample HdrInfo specification:

             struct hdrinfo                    HdrInfo[] =
             {
                      /* originator fields, most to least significant  */
                 "resent-sender",              H_FROM,
                 "resent-from",                H_FROM,
                 "sender",                     H_FROM,
                 "from",                       H_FROM,
                 "full-name",                  H_ACHECK,
                 "errors-to",                  H_FROM|H_ERRORSTO,
                      /* destination fields */
                 "to",                         H_RCPT,
                 "resent-to",                  H_RCPT,
                 "cc",                         H_RCPT,
                 "bcc",                        H_RCPT|H_STRIPVAL,
                      /* message identification and control */
                 "message",                    H_EOH,
                 "text",                       H_EOH,
                      /* trace fields */
                 "received",                   H_TRACE|H_FORCE,
                      /* miscellaneous fields */
                 "content-transfer-encoding",  H_CTE,
                 "content-type",               H_CTYPE,

                 NULL,                         0,
             };

         This structure indicates that the  "To:",  "Resent-
         To:",   and  "Cc:"  fields  all  specify  recipient
         addresses.  Any "Full-Name:" field will be  deleted
         unless  the  required mailer flag (indicated in the
         configuration file) is specified.   The  "Message:"
         and "Text:" fields will terminate the header; these
         are used by random dissenters  around  the  network
         world.  The "Received:" field will always be added,
         and can be used to trace messages.

              There are a number of important  points  here.
         First,  header  fields  are not added automatically
         just because they are  in  the  HdrInfo  structure;
         they must be specified in the configuration file in
         order to be  added  to  the  message.   Any  header
         fields  mentioned in the configuration file but not
         mentioned in the  HdrInfo  structure  have  default
         processing  performed;  that  is,  they  are  added
         unless they were in the message  already.   Second,
         the  HdrInfo  structure only specifies cliched pro-
         cessing; certain headers are processed specially by
         ad  hoc  code regardless of the status specified in
         HdrInfo.  For example, the  "Sender:"  and  "From:"
         fields are always scanned on ARPANET mail to deter-











Sendmail Installation and Operation Guide         SMM:08-157


         mine the sender[24]; this is used  to  perform  the
         "return  to  sender"  function.   The  "From:"  and
         "Full-Name:" fields are used to determine the  full
         name  of  the sender if possible; this is stored in
         the macro $x and used in a number of ways.

      6.3.2.  Restricting Use of Email

              If it is necessary to restrict mail through  a
         relay,  the  checkcompat  routine  can be modified.
         This routine is called for every recipient address.
         It  returns an exit status indicating the status of
         the message.  The status EX_OK accepts the address,
         EX_TEMPFAIL queues the message for a later try, and
         other values (commonly EX_UNAVAILABLE)  reject  the
         message.  It is up to checkcompat to print an error
         message (using usrerr) if the message is  rejected.
         For example, checkcompat could read:

             int
             checkcompat(to, e)
                 register ADDRESS *to;
                 register ENVELOPE *e;
             {
                 register STAB *s;

                 s = stab("private", ST_MAILER, ST_FIND);
                 if (s != NULL && e->e_from.q_mailer != LocalMailer &&
                     to->q_mailer == s->s_mailer)
                 {
                     usrerr("No private net mail allowed through this machine");
                     return (EX_UNAVAILABLE);
                 }
                 if (MsgSize > 50000 && bitnset(M_LOCALMAILER, to->q_mailer))
                 {
                     usrerr("Message too large for non-local delivery");
                     e->e_flags |= EF_NORETURN;
                     return (EX_UNAVAILABLE);
                 }
                 return (EX_OK);
             }

         This would reject messages greater than 50000 bytes
         unless they were local.  The EF_NORETURN  flag  can
         be  set in e->e_flags to suppress the return of the
         actual body of the message  in  the  error  return.
         The  actual use of this routine is highly dependent
         on the implementation, and use should be limited.
____________________
   [24]Actually, this is no longer true in SMTP; this infor-
mation is contained in the envelope.  The older ARPANET pro-
tocols did not completely distinguish envelope from header.











SMM:08-158         Sendmail Installation and Operation Guide


      6.3.3.  New Database Map Classes

              New key maps can be added by creating a  class
         initialization  function  and  a  lookup  function.
         These are then added to the routine setupmaps.

              The initialization function is called as

             xxx_map_init(MAP *map, char *args)

         The map is an internal data structure.  The args is
         a  pointer to the portion of the configuration file
         line following the map class name; flags and  file-
         names  can  be  extracted from this line.  The ini-
         tialization function must return true  if  it  suc-
         cessfully opened the map, false otherwise.

              The lookup function is called as

             xxx_map_lookup(MAP *map, char buf[], char **av, int *statp)

         The  map  defines  the map internally.  The buf has
         the input key.  This may be  (and  often  is)  used
         destructively.   The  av  is  a  list  of arguments
         passed in from the rewrite line.  The lookup  func-
         tion  should return a pointer to the new value.  If
         the map lookup fails, *statp should be  set  to  an
         exit  status  code; in particular, it should be set
         to EX_TEMPFAIL if recovery is to  be  attempted  by
         the higher level code.

      6.3.4.  Queueing Function

              The routine shouldqueue is called to decide if
         a message should be  queued  or  processed  immedi-
         ately.   Typically this compares the message prior-
         ity to the current load average.  The default defi-
         nition is:

             bool
             shouldqueue(pri, ctime)
                 long pri;
                 time_t ctime;
             {
                 if (CurrentLA < QueueLA)
                     return false;
                 return (pri > (QueueFactor / (CurrentLA - QueueLA + 1)));
             }

         If  the  current load average (global variable Cur-
         rentLA,  which  is  set  before  this  function  is
         called) is less than the low threshold load average
         (option x, variable QueueLA),  shouldqueue  returns










Sendmail Installation and Operation Guide         SMM:08-159


         false  immediately  (that is, it should not queue).
         If  the  current  load  average  exceeds  the  high
         threshold   load   average   (option   X,  variable
         RefuseLA), shouldqueue  returns  true  immediately.
         Otherwise,  it  computes  the function based on the
         message  priority,  the  queue  factor  (option  q,
         global  variable  QueueFactor), and the current and
         threshold load averages.

              An implementation wishing to take  the  actual
         age  of  the  message into account can also use the
         ctime parameter, which is the time that the message
         was first submitted to sendmail.  Note that the pri
         parameter is already  weighted  by  the  number  of
         times  the  message  has  been tried (although this
         tends to lower the priority  of  the  message  with
         time);  the  expectation is that the ctime would be
         used as an "escape clause" to ensure that  messages
         are eventually processed.

      6.3.5.  Refusing Incoming SMTP Connections

              The function refuseconnections returns true if
         incoming SMTP connections should be  refused.   The
         current  implementation is based exclusively on the
         current load average and the  refuse  load  average
         option (option X, global variable RefuseLA):

             bool
             refuseconnections()
             {
                 return (RefuseLA > 0 && CurrentLA >= RefuseLA);
             }

         A  more  clever  implementation  could look at more
         system resources.

      6.3.6.  Load Average Computation

              The routine getla  returns  the  current  load
         average  (as  a rounded integer).  The distribution
         includes several possible implementations.  If  you
         are  porting  to  a new environment you may need to
         add some new tweaks.[25]




____________________
   [25]If you do,  please  send  updates  to  sendmail@Send-
mail.ORG.












SMM:08-160         Sendmail Installation and Operation Guide


   6.4.  Configuration in sendmail/daemon.c

           The  file  sendmail/daemon.c contains a number of
      routines that are dependent on  the  local  networking
      environment.   The  version  supplied assumes you have
      BSD style sockets.

           In previous releases,  we  recommended  that  you
      modify the routine maphostname if you wanted to gener-
      alize $[ ... $] lookups.  We now  recommend  that  you
      create a new keyed map instead.

   6.5.  LDAP

           In  this section we assume that sendmail has been
      compiled with support for LDAP.

      6.5.1.  LDAP Recursion

              LDAP Recursion allows you to add types to  the
         search  attributes  on  an  LDAP map specification.
         The syntax is:

         -v ATTRIBUTE[:TYPE[:OBJECTCLASS[|OBJECTCLASS|...]]]


              The new TYPEs are:

         NORMAL    This   attribute   type   specifies   the
                   attribute to add to the  results  string.
                   This is the default.

         DN        Any   matches   for  this  attribute  are
                   expected to have a value of a fully qual-
                   ified  distinguished name.  sendmail will
                   lookup that DN and apply  the  attributes
                   requested to the returned DN record.

         FILTER    Any   matches   for  this  attribute  are
                   expected to  have  a  value  of  an  LDAP
                   search  filter.   sendmail will perform a
                   lookup with the same  parameters  as  the
                   original  search  but replaces the search
                   filter with the one specified here.

         URL       Any  matches  for  this   attribute   are
                   expected  to have a value of an LDAP URL.
                   sendmail will perform a  lookup  of  that
                   URL   and   use   the  results  from  the
                   attributes named in that URL.  Note  how-
                   ever  that  the  search is done using the
                   current LDAP  connection,  regardless  of
                   what  is  specified  as  the scheme, LDAP










Sendmail Installation and Operation Guide         SMM:08-161


                   host, and LDAP port in the LDAP URL.

         Any  untyped  attributes  are   considered   NORMAL
         attributes as described above.

              The  optional  OBJECTCLASS  (| separated) list
         contains the  objectClass  values  for  which  that
         attribute  applies.   If  the  list  is  given, the
         attribute named will  only  be  used  if  the  LDAP
         record  being  returned  is a member of that object
         class.  Note that  if  these  new  value  attribute
         TYPEs  are  used in an AliasFile option setting, it
         will need to be double quoted to  prevent  sendmail
         from misparsing the colons.

              Note  that  LDAP recursion attributes which do
         not ultimately point to an LDAP record are not con-
         sidered an error.

         6.5.1.1.  Example

                 Since  examples  usually help clarify, here
            is an example which uses all  four  of  the  new
            types:

                O LDAPDefaultSpec=-h ldap.example.com -b dc=example,dc=com

                Kexample ldap
                         -z,
                         -k (&(objectClass=sendmailMTAAliasObject)(sendmailMTAKey=%0))
                         -v sendmailMTAAliasValue,mail:NORMAL:inetOrgPerson,
                            uniqueMember:DN:groupOfUniqueNames,
                            sendmailMTAAliasSearch:FILTER:sendmailMTAAliasObject,
                            sendmailMTAAliasURL:URL:sendmailMTAAliasObject


                 That definition specifies that:

             + Any    value   in   a   sendmailMTAAliasValue
               attribute will be added to the result  string
               regardless of object class.
             + The  mail  attribute  will  be  added  to the
               result string if the LDAP record is a  member
               of the inetOrgPerson object class.
             + The  uniqueMember  attribute  is  a recursive
               attribute, used  only  in  groupOfUniqueNames
               records, and should contain an LDAP DN point-
               ing to another LDAP record.  The desire  here
               is  to  return  the mail attribute from those
               DNs.
             + The  sendmailMTAAliasSearch   attribute   and
               sendmailMTAAliasURL  are  both  used  only if
               referenced in a sendmailMTAAliasObject.  They










SMM:08-162         Sendmail Installation and Operation Guide


               are  both recursive, the first for a new LDAP
               search string and the latter for an LDAP URL.

   6.6.  STARTTLS

           In this section we assume that sendmail has  been
      compiled  with  support  for  STARTTLS.   To  properly
      understand the use of STARTTLS in sendmail, it is nec-
      essary  to understand at least some basics about X.509
      certificates and public key cryptography.  This infor-
      mation  can  be found in books about SSL/TLS or on WWW
      sites, e.g., "http://www.OpenSSL.org/".

      6.6.1.  Certificates for STARTTLS

              When acting as  a  server,  sendmail  requires
         X.509 certificates to support STARTTLS: one as cer-
         tificate for the server (ServerCertFile and  corre-
         sponding  private  ServerKeyFile) at least one root
         CA (CACertFile), i.e., a certificate that  is  used
         to  sign other certificates, and a path to a direc-
         tory which contains other  CAs  (CACertPath).   The
         file  specified  via CACertFile can contain several
         certificates of CAs.  The DNs of these certificates
         are sent to the client during the TLS handshake (as
         part of the  CertificateRequest)  as  the  list  of
         acceptable CAs.  However, do not list too many root
         CAs in that file, otherwise the TLS  handshake  may
         fail; e.g.,

             error:14094417:SSL routines:SSL3_READ_BYTES:
             sslv3 alert illegal parameter:s3_pkt.c:964:SSL alert number 47

         You  should probably put only the CA cert into that
         file that signed your own cert(s), or at least only
         those  you  trust.   The  CACertPath directory must
         contain the hashes of each CA certificate as  file-
         names (or as links to them).  Symbolic links can be
         generated with the  following  two  (Bourne)  shell
         commands:

             C=FileName_of_CA_Certificate
             ln -s $C `openssl x509 -noout -hash < $C`.0

         An X.509 certificate is also required for authenti-
         cation in client mode  (ClientCertFile  and  corre-
         sponding  private ClientKeyFile), however, sendmail
         will always use STARTTLS when offered by a  server.
         The  client  and server certificates can be identi-
         cal.  Certificates can be obtained from a  certifi-
         cate authority or created with the help of OpenSSL.
         The required format for  certificates  and  private
         keys  is  PEM.   To  allow for automatic startup of










Sendmail Installation and Operation Guide         SMM:08-163


         sendmail, private keys  (ServerKeyFile,  ClientKey-
         File)  must  be  stored  unencrypted.  The keys are
         only protected by the permissions of the file  sys-
         tem.  Never make a private key available to a third
         party.

      6.6.2.  PRNG for STARTTLS

              STARTTLS requires a strong pseudo random  num-
         ber  generator (PRNG) to operate properly.  Depend-
         ing on the TLS library you use, it may be  required
         to explicitly initialize the PRNG with random data.
         OpenSSL makes use of /dev/urandom(4)  if  available
         (this  corresponds  to  the  compile  flag HASURAN-
         DOMDEV).  On systems which  lack  this  support,  a
         random  file  must  be specified in the sendmail.cf
         file using the option  RandFile.   It  is  strongly
         advised  to  use the "Entropy Gathering Daemon" EGD
         from Brian Warner on those systems to provide  use-
         ful  random  data.   In this case, sendmail must be
         compiled with the flag EGD, and the RandFile option
         must   point   to   the  EGD  socket.   If  neither
         /dev/urandom(4) nor EGD are available, you have  to
         make  sure that useful random data is available all
         the time in RandFile.  If the file hasn't been mod-
         ified  in the last 10 minutes before it is supposed
         to be used by sendmail the  content  is  considered
         obsolete.  One method for generating this file is:

             openssl rand -out /etc/mail/randfile -rand /path/to/file:...256

         See the OpenSSL documentation for more information.
         In this case, the PRNG for TLS is only seeded  with
         other  random  data if the DontBlameSendmail option
         InsufficientEntropy is set.  This  is  most  likely
         not  sufficient  for certain actions, e.g., genera-
         tion of (temporary) keys.

              Please see the OpenSSL documentation or  other
         sources for further information about certificates,
         their creation and their usage, the importance of a
         good PRNG, and other aspects of TLS.

   6.7.  Encoding of STARTTLS and AUTH related Macros

           Macros  that  contain  STARTTLS  and AUTH related
      data which  comes  from  outside  sources,  e.g.,  all
      macros  containing  information from certificates, are
      encoded to avoid problems with non-printable  or  spe-
      cial  characters.   The latter are '\', '<', '>', '(',
      ')', '"', '+', and ' '.  All of these  characters  are
      replaced  by their value in hexadecimal with a leading
      '+'.  For example:










SMM:08-164         Sendmail Installation and Operation Guide


          /C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/
          Email=darth+cert@endmail.org

      is encoded as:

          /C=US/ST=California/O=endmail.org/OU=private/
          CN=Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org

      (line breaks have been inserted for readability).  The
      macros   which   are  subject  to  this  encoding  are
      {cert_subject},      {cert_issuer},      {cn_subject},
      {cn_issuer},    as    well    as   {auth_authen}   and
      {auth_author}.

7.  ACKNOWLEDGEMENTS

        I've worked on sendmail for  many  years,  and  many
   employers  have  been remarkably patient about letting me
   work on a large project that was not part of my  official
   job.   This  includes  time  on the INGRES Project at the
   University of California at Berkeley, at Britton Lee, and
   again on the Mammoth and Titan Projects at Berkeley.

        Much of the second wave of improvements resulting in
   version 8.1 should be credited to Bryan Costales  of  the
   International  Computer  Science Institute.  As he passed
   me drafts of his book on sendmail I was inspired to start
   working  on  things  again.   Bryan was also available to
   bounce ideas off of.

        Gregory Neil Shapiro of Worcester Polytechnic Insti-
   tute  has  become  instrumental in all phases of sendmail
   support and development, and was largely responsible  for
   getting versions 8.8 and 8.9 out the door.

        Many,  many  people  contributed  chunks of code and
   ideas to sendmail.  It has proven to be a  group  network
   effort.   Version  8  in  particular was a group project.
   The following people and organizations made notable  con-
   tributions:

       Claus Assmann
       John Beck, Hewlett-Packard & Sun Microsystems
       Keith Bostic, CSRG, University of California, Berkeley
       Andrew Cheng, Sun Microsystems
       Michael J. Corrigan, University of California, San Diego
       Bryan Costales, International Computer Science Institute & InfoBeat
       Par (Pell) Emanuelsson
       Craig Everhart, Transarc Corporation
       Per Hedeland, Ericsson
       Tom Ivar Helbekkmo, Norwegian School of Economics
       Kari Hurtta, Finnish Meteorological Institute
       Allan E. Johannesen, WPI










Sendmail Installation and Operation Guide         SMM:08-165


       Jonathan Kamens, OpenVision Technologies, Inc.
       Takahiro Kanbe, Fuji Xerox Information Systems Co., Ltd.
       Brian Kantor, University of California, San Diego
       John Kennedy, Cal State University, Chico
       Murray S. Kucherawy, HookUp Communication Corp.
       Bruce Lilly, Sony U.S.
       Karl London
       Motonori Nakamura, Ritsumeikan University & Kyoto University
       John Gardiner Myers, Carnegie Mellon University
       Neil Rickert, Northern Illinois University
       Gregory Neil Shapiro, WPI
       Eric Schnoebelen, Convex Computer Corp.
       Eric Wassenaar, National Institute for Nuclear and High Energy Physics, Amsterdam
       Randall Winchester, University of Maryland
       Christophe Wolfhugel, Pasteur Institute & Herve Schauer Consultants (Paris)
       Exactis.com, Inc.

   I apologize for anyone I have omitted, misspelled, misat-
   tributed, or otherwise missed.  At this point, I  suspect
   that at least a hundred people have contributed code, and
   many more have contributed ideas, comments,  and  encour-
   agement.  I've tried to list them in the RELEASE_NOTES in
   the distribution directory.  I appreciate their contribu-
   tion as well.

        Special thanks are reserved for Michael Corrigan and
   Christophe Wolfhugel, who besides being wonderful  guinea
   pigs  and contributors have also consented to be added to
   the ``sendmail@Sendmail.ORG'' list and, by answering  the
   bulk of the questions sent to that list, have freed me up
   to do other work.



































                          APPENDIX  A


                      COMMAND LINE FLAGS




     Arguments  must  be   presented   with   flags   before
addresses.  The flags are:

-Ax       Select  an  alternative  .cf  file which is either
          sendmail.cf for -Am  or  submit.cf  for  -Ac.   By
          default the .cf file is chosen based on the opera-
          tion mode.  For -bm (default), -bs, and -t  it  is
          submit.cf if it exists, for all others it is send-
          mail.cf.

-bx       Set operation mode to x.  Operation modes are:

              m   Deliver mail (default)
              s   Speak SMTP on input side
              a*  ``Arpanet'' mode (get envelope sender information from header)
              d   Run as a daemon in background
              D   Run as a daemon in foreground
              t   Run in test mode
              v   Just verify addresses, don't collect or deliver
              i   Initialize the alias database
              p   Print the mail queue
              P   Print overview over the mail queue (requires shared memory)
              h   Print the persistent host status database
              H   Purge expired entries from the persistent host status database


-Btype    Indicate body type.

-Cfile    Use a different configuration file.  Sendmail runs
          as  the invoking user (rather than root) when this
          flag is specified.

-D logfile
          Send debugging output  to  the  indicated  logfile
          instead of stdout.

-dlevel   Set debugging level.

-f addr   The  envelope sender address is set to addr.  This
          address may also be used in the  From:  header  if
          that  header is missing during initial submission.
____________________
   *Deprecated.




SMM:08-166         Sendmail Installation and Operation Guide







Sendmail Installation and Operation Guide         SMM:08-167


          The envelope sender address is used as the recipi-
          ent for delivery status notifications and may also
          appear in a Return-Path: header.

-F name   Sets the full name of this user to name.

-G        When accepting  messages  via  the  command  line,
          indicate that they are for relay (gateway) submis-
          sion.  sendmail may complain  about  syntactically
          invalid  messages,  e.g.,  unqualified host names,
          rather than fixing them when  this  flag  is  set.
          sendmail  will not do any canonicalization in this
          mode.

-h cnt    Sets the "hop count" to cnt.  This represents  the
          number of times this message has been processed by
          sendmail (to the extent that it  is  supported  by
          the underlying networks).  Cnt is incremented dur-
          ing processing, and if  it  reaches  MAXHOP  (cur-
          rently  25)  sendmail throws away the message with
          an error.

-L tag    Sets the identifier used for  syslog.   Note  that
          this identifier is set as early as possible.  How-
          ever, sendmail  may  be  used  if  problems  arise
          before the command line arguments are processed.

-n        Don't do aliasing or forwarding.

-N notifications
          Tag  all addresses being sent as wanting the indi-
          cated notifications, which consists  of  the  word
          "NEVER"  or  a  comma-separated list of "SUCCESS",
          "FAILURE", and "DELAY"  for  successful  delivery,
          failure,  and  a  message that is stuck in a queue
          somewhere.  The default is "FAILURE,DELAY".

-r addr   An obsolete form of -f.

-oxvalue  Set  option  x  to  the  specified  value.   These
          options are described in Section 5.6.

-Ooption=value
          Set  option  to the specified value (for long form
          option names).  These  options  are  described  in
          Section 5.6.

-Mxvalue  Set macro x to the specified value.

-pprotocol
          Set the sending protocol.  Programs are encouraged
          to set this.  The protocol field  can  be  in  the
          form   protocol:host   to  set  both  the  sending










SMM:08-168         Sendmail Installation and Operation Guide


          protocol   and   sending   host.    For   example,
          "-pUUCP:uunet"  sets  the sending protocol to UUCP
          and the sending host  to  uunet.   (Some  existing
          programs  use  -oM to set the r and s macros; this
          is equivalent to using -p.)

-qtime    Try to process the queued up mail.  If the time is
          given, a sendmail will start one or more processes
          to run through the queue(s) at the specified  time
          interval  to  deliver  queued  mail; otherwise, it
          only runs once.  Each of these processes acts on a
          workgroup.   These  processes  are  also  known as
          workgroup processes  or  WGP's  for  short.   Each
          workgroup  is responsible for controlling the pro-
          cessing of one or  more  queues;  workgroups  help
          manage  the  use  of system resources by sendmail.
          Each workgroup may have one or more children  con-
          currently  processing queues depending on the set-
          ting of MaxQueueChildren.

-qptime   Similar to -q with a time  argument,  except  that
          instead  of  periodically  starting WGP's sendmail
          starts persistent  WGP's  that  alternate  between
          processing queues and sleeping.  The sleep time is
          specified by the time argument; it defaults  to  1
          second, except that a WGP always sleeps at least 5
          seconds if their queues were empty in the previous
          run.   Persistent processes are managed by a queue
          control process (QCP).   The  QCP  is  the  parent
          process  of  the WGP's.  Typically the QCP will be
          the sendmail daemon (when started with -bd or -bD)
          or  a  special process (named Queue control) (when
          started without -bd or -bD).  If a persistent  WGP
          ceases  to  be  active for some reason another WGP
          will be started by the QCP for the same  workgroup
          in  most  cases.  When  a  persistent WGP has core
          dumped, the debug  flag  no_persistent_restart  is
          set  or  the  specific  persistent  WGP  has  been
          restarted too many times already then the WGP will
          not  be started again and a message will be logged
          to this effect.   To  stop  (SIGTERM)  or  restart
          (SIGHUP)  persistent  WGP's the appropriate signal
          should be sent to the QCP. The QCP will  propagate
          the  signal to all of the WGP's and if appropriate
          restart the persistent WGP's.

-qGname   Run the jobs in the queue group name once.

-q[!]Xstring
          Run the queue once, limiting  the  jobs  to  those
          matching  Xstring.   The  key letter X can be I to
          limit based on queue identifier, R to limit  based
          on  recipient, S to limit based on sender, or Q to










Sendmail Installation and Operation Guide         SMM:08-169


          limit based on quarantine reason  for  quarantined
          jobs.   A particular queued job is accepted if one
          of the corresponding attributes contains the indi-
          cated  string.   The  optional ! character negates
          the condition tested.  Multiple -qX flags are per-
          mitted,  with  items  with  the  same  key  letter
          "or'ed" together, and  items  with  different  key
          letters "and'ed" together.

-Q[reason]
          Quarantine  a  normal  queue  items with the given
          reason or unquarantine quarantined queue items  if
          no reason is given.  This should only be used with
          some sort of item matching using  -q[!]Xstring  as
          described above.

-R ret    What  information you want returned if the message
          bounces; ret can be "HDRS"  for  headers  only  or
          "FULL"  for  headers plus body.  This is a request
          only; the other end is not required to  honor  the
          parameter.   If  "HDRS" is specified local bounces
          also return only the headers.

-t        Read the  header  for  "To:",  "Cc:",  and  "Bcc:"
          lines, and send to everyone listed in those lists.
          The "Bcc:" line will be  deleted  before  sending.
          Any  addresses  in  the  argument  vector  will be
          deleted from the send list.

-V envid  The indicated envid is passed with the envelope of
          the message and returned if the message bounces.

-X logfile
          Log  all  traffic  in  and  out of sendmail in the
          indicated logfile for debugging  mailer  problems.
          This  produces  a  lot  of  data  very quickly and
          should be used sparingly.

     There are a number of options that may be specified  as
primitive  flags.   These  are  the  e, i, m, and v options.
Also, the f option may be specified as the -s flag.  The DSN
related  options  "-N",  "-R",  and  "-V" have no effects on
sendmail running as daemon.























                        APPENDIX  B


                     QUEUE FILE FORMATS




     This appendix describes the format of the queue  files.
These  files  live in a queue directory.  The individual qf,
hf, Qf, df, and xf files may be stored in separate qf/, df/,
and  xf/  subdirectories  if  they  are present in the queue
directory.

     All queue files have  the  name  ttYMDhmsNNppppp  where
YMDhmsNNppppp  is  the  id  for this message and the tt is a
type.  The individual letters in the id are:

Y    Encoded year

M    Encoded month

D    Encoded day

h    Encoded hour

m    Encoded minute

s    Encoded second

NN   Encoded envelope number

ppppp
     At least five decimal digits of the process ID

     All files with the same id collectively define one mes-
sage.   Due  to  the  use  of memory-buffered files, some of
these files may never appear on disk.

     The types are:

qf   The queue control file.  This file contains the  infor-
     mation necessary to process the job.

hf   The same as a queue control file, but for a quarantined
     queue job.

df   The data file.  The message body (excluding the header)
     is  kept  in  this  file.  Sometimes the df file is not
     stored in the same directory as the qf  file;  in  this
     case, the qf file contains a `d' record which names the
     queue directory that contains the df file.



SMM:08-170         Sendmail Installation and Operation Guide







Sendmail Installation and Operation Guide         SMM:08-171


tf   A temporary file.  This is an image of the qf file when
     it is being rebuilt.  It should be renamed to a qf file
     very quickly.

xf   A transcript file, existing during the life of  a  ses-
     sion  showing  everything that happens during that ses-
     sion.  Sometimes the xf file must be generated before a
     queue  group  has  been  selected; in this case, the xf
     file will be stored in a directory of the default queue
     group.

Qf   A  ``lost''  queue control file.  sendmail renames a qf
     file to Qf if there is a severe (configuration) problem
     that  cannot  be  solved  without  human  intervention.
     Search the logfile for the queue file id to figure  out
     what happened.  After you resolved the problem, you can
     rename the Qf file to qf and send it again.

     The queue control file is structured  as  a  series  of
lines  each  beginning with a code letter.  The lines are as
follows:

V    The version number of the queue file  format,  used  to
     allow new sendmail binaries to read queue files created
     by older versions.  Defaults to version zero.  Must  be
     the  first  line  of the file if present.  For 8.12 the
     version number is 6.

A    The information given by the  AUTH=  parameter  of  the
     "MAIL  FROM:"  command  or  $f@$j  if sendmail has been
     called directly.

H    A header definition.  There may be any number of  these
     lines.   The  order  is  important:  they represent the
     order in the final message.  These use the same  syntax
     as header definitions in the configuration file.

C    The     controlling    address.     The    syntax    is
     "localuser:aliasname".  Recipient  addresses  following
     this  line  will  be flagged so that deliveries will be
     run as the localuser (a user name from the  /etc/passwd
     file); aliasname is the name of the alias that expanded
     to this address (used for printing messages).

q    The quarantine reason for quarantined queue items.

Q    The ``original recipient'',  specified  by  the  ORCPT=
     field  in  an  ESMTP transaction.  Used exclusively for
     Delivery Status Notifications.  It applies only to  the
     following `R' line.

r    The  ``final recipient'' used for Delivery Status Noti-
     fications.  It applies only to the following `R' line.










SMM:08-172         Sendmail Installation and Operation Guide


R    A recipient address.  This will normally be  completely
     aliased, but is actually realiased when the job is pro-
     cessed.  There will be one  line  for  each  recipient.
     Version  1 qf files also include a leading colon-termi-
     nated list of flags, which can be `S' to return a  mes-
     sage on successful final delivery, `F' to return a mes-
     sage on failure, `D' to return a message if the message
     is  delayed,  `B'  to  indicate that the body should be
     returned, `N' to suppress returning the body,  and  `P'
     to declare this as a ``primary'' (command line or SMTP-
     session) address.

S    The sender address.  There may only  be  one  of  these
     lines.

T    The job creation time.  This is used to compute when to
     time out the job.

P    The current message priority.  This is  used  to  order
     the  queue.  Higher numbers mean lower priorities.  The
     priority changes as the message sits in the queue.  The
     initial  priority  depends on the message class and the
     size of the message.

M    A message.  This line is printed by the mailq  command,
     and  is generally used to store status information.  It
     can contain any text.

F    Flag bits, represented as one letter per flag.  Defined
     flag bits are r indicating that this is a response mes-
     sage and w indicating that a warning message  has  been
     sent  announcing that the mail has been delayed.  Other
     flag bits are: 8: the body contains  8bit  data,  b:  a
     Bcc:  header  should  be  removed,  d: the mail has RET
     parameters (see RFC 1894), n: the body of  the  message
     should  not  be  returned  in  case of an error, s: the
     envelope has been split.

N    The total number of delivery attempts.

K    The time (as seconds since January 1, 1970) of the last
     delivery attempt.

d    If  the df file is in a different directory than the qf
     file, then a `d'  record  is  present,  specifying  the
     directory in which the df file resides.

I    The  i-number  of  the  data  file; this can be used to
     recover your mail queue after a disastrous disk crash.

$    A macro definition.  The values of certain  macros  are
     passed through to the queue run phase.











Sendmail Installation and Operation Guide         SMM:08-173


B    The  body  type.   The  remainder of the line is a text
     string defining the body type.  If this field is  miss-
     ing,  the body type is assumed to be "undefined" and no
     special processing  is  attempted.   Legal  values  are
     "7BIT" and "8BITMIME".

Z    The  original envelope id (from the ESMTP transaction).
     For Deliver Status Notifications only.

     As an example, the following is a queue  file  sent  to
"eric@mammoth.Berkeley.EDU"   and  "bostic@okeeffe.CS.Berke-
ley.EDU"[1]:

    V4
    T711358135
    K904446490
    N0
    P2100941
    $_eric@localhost
    ${daemon_flags}
    Seric
    Ceric:100:1000:sendmail@vangogh.CS.Berkeley.EDU
    RPFD:eric@mammoth.Berkeley.EDU
    RPFD:bostic@okeeffe.CS.Berkeley.EDU
    H?P?Return-path: <^g>
    H??Received: by vangogh.CS.Berkeley.EDU (5.108/2.7) id AAA06703;
        Fri, 17 Jul 1992 00:28:55 -0700
    H??Received: from mail.CS.Berkeley.EDU by vangogh.CS.Berkeley.EDU (5.108/2.7)
        id AAA06698; Fri, 17 Jul 1992 00:28:54 -0700
    H??Received: from [128.32.31.21] by mail.CS.Berkeley.EDU (5.96/2.5)
        id AA22777; Fri, 17 Jul 1992 03:29:14 -0400
    H??Received: by foo.bar.baz.de (5.57/Ultrix3.0-C)
        id AA22757; Fri, 17 Jul 1992 09:31:25 GMT
    H?F?From: eric@foo.bar.baz.de (Eric Allman)
    H?x?Full-name: Eric Allman
    H??Message-id: <9207170931.AA22757@foo.bar.baz.de>
    H??To: sendmail@vangogh.CS.Berkeley.EDU
    H??Subject: this is an example message

This shows the person who sent the message,  the  submission
time  (in seconds since January 1, 1970), the message prior-
ity, the message class, the recipients, and the headers  for
the message.




____________________
   [1]This example is contrived and probably inaccurate  for
your  environment.   Glance  over it to get an idea; nothing
can replace looking at what your own system generates.















                        APPENDIX  C


                  SUMMARY OF SUPPORT FILES




     This  is  a  summary of the support files that sendmail
creates or generates.  Many of these can be changed by edit-
ing  the  sendmail.cf  file;  check there to find the actual
pathnames.

/usr/sbin/sendmail
          The binary of sendmail.

/usr/bin/newaliases
          A link to  /usr/sbin/sendmail;  causes  the  alias
          database  to  be rebuilt.  Running this program is
          completely equivalent to giving sendmail  the  -bi
          flag.

/usr/bin/mailq
          Prints  a listing of the mail queue.  This program
          is equivalent to using the -bp flag to sendmail.

/etc/mail/sendmail.cf
          The configuration file, in textual form.

/etc/mail/helpfile
          The SMTP help file.

/etc/mail/statistics
          A statistics file; need not be present.

/etc/mail/sendmail.pid
          Created in daemon mode; it contains the process id
          of  the  current  SMTP daemon.  If you use this in
          scripts; use ``head -1'' to  get  just  the  first
          line;  the  second  line contains the command line
          used to invoke the daemon, and later  versions  of
          sendmail  may  add  more information to subsequent
          lines.

/etc/mail/aliases
          The textual version of the alias file.

/etc/mail/aliases.db
          The alias file in hash(3) format.

/etc/mail/aliases.{pag,dir}
          The alias file in ndbm(3) format.



SMM:08-174         Sendmail Installation and Operation Guide







Sendmail Installation and Operation Guide         SMM:08-175


/var/spool/mqueue
          The directory in which the mail queue(s) and  tem-
          porary files reside.

/var/spool/mqueue/qf*
          Control (queue) files for messages.

/var/spool/mqueue/df*
          Data files.

/var/spool/mqueue/tf*
          Temporary  versions  of  the qf files, used during
          queue file rebuild.

/var/spool/mqueue/xf*
          A transcript of the current session.















































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Sendmail Installation and Operation Guide           SMM:08-3


                          TABLE OF CONTENTS

1.  BASIC INSTALLATION ................................    7
   1.1.  Compiling Sendmail ...........................    7
      1.1.1.  Tweaking the Build Invocation ...........    7
      1.1.2.  Creating a Site Configuration File ......    8
      1.1.3.  Tweaking the Makefile ...................    8
      1.1.4.  Compilation and installation ............    9
   1.2.  Configuration Files ..........................   10
   1.3.  Details of Installation Files ................   12
      1.3.1.  /usr/sbin/sendmail ......................   12
      1.3.2.  /etc/mail/sendmail.cf ...................   12
      1.3.3.  /etc/mail/submit.cf .....................   13
      1.3.4.  /usr/bin/newaliases .....................   13
      1.3.5.  /usr/bin/hoststat .......................   13
      1.3.6.  /usr/bin/purgestat ......................   13
      1.3.7.  /var/spool/mqueue .......................   14
      1.3.8.  /var/spool/clientmqueue .................   14
      1.3.9.  /var/spool/mqueue/.hoststat .............   15
      1.3.10.  /etc/mail/aliases* .....................   15
      1.3.11.  /etc/rc or /etc/init.d/sendmail ........   15
      1.3.12.  /etc/mail/helpfile .....................   16
      1.3.13.  /etc/mail/statistics ...................   16
      1.3.14.  /usr/bin/mailq .........................   16
      1.3.15.  sendmail.pid ...........................   18
      1.3.16.  Map Files ..............................   18
2.  NORMAL OPERATIONS .................................   19
   2.1.  The System Log ...............................   19
      2.1.1.  Format ..................................   19
      2.1.2.  Levels ..................................   20
   2.2.  Dumping State ................................   21
   2.3.  The Mail Queues ..............................   21
      2.3.1.  Queue Groups and Queue Directories ......   21
      2.3.2.  Queue Runs ..............................   22
      2.3.3.  Manual Intervention .....................   23
      2.3.4.  Printing the queue ......................   23
      2.3.5.  Forcing the queue .......................   24
      2.3.6.  Quarantined Queue Items .................   25
   2.4.  Disk Based Connection Information ............   26
   2.5.  The Service Switch ...........................   27
   2.6.  The Alias Database ...........................   28
      2.6.1.  Rebuilding the alias database ...........   30
      2.6.2.  Potential problems ......................   30
      2.6.3.  List owners .............................   31
   2.7.  User Information Database ....................   31
   2.8.  Per-User Forwarding (.forward Files) .........   32
   2.9.  Special Header Lines .........................   32
      2.9.1.  Errors-To: ..............................   32
      2.9.2.  Apparently-To: ..........................   33
      2.9.3.  Precedence ..............................   33
   2.10.  IDENT Protocol Support ......................   33
3.  ARGUMENTS .........................................   34
   3.1.  Queue Interval ...............................   34










SMM:08-4           Sendmail Installation and Operation Guide


   3.2.  Daemon Mode ..................................   35
   3.3.  Forcing the Queue ............................   35
   3.4.  Debugging ....................................   36
   3.5.  Changing the Values of Options ...............   37
   3.6.  Trying a Different Configuration File ........   37
   3.7.  Logging Traffic ..............................   38
   3.8.  Testing Configuration Files ..................   38
   3.9.  Persistent Host Status Information ...........   40
4.  TUNING ............................................   40
   4.1.  Timeouts .....................................   41
      4.1.1.  Queue interval ..........................   41
      4.1.2.  Read timeouts ...........................   41
      4.1.3.  Message timeouts ........................   44
   4.2.  Forking During Queue Runs ....................   45
   4.3.  Queue Priorities .............................   46
   4.4.  Load Limiting ................................   47
   4.5.  Resource Limits ..............................   47
   4.6.  Measures against Denial of Service  Attacks
      .................................................   48
   4.7.  Delivery Mode ................................   48
   4.8.  Log Level ....................................   49
   4.9.  File Modes ...................................   50
      4.9.1.  To suid or not to suid?  ................   50
      4.9.2.  Turning off security checks .............   51
   4.10.  Connection Caching ..........................   54
   4.11.  Name Server Access ..........................   55
   4.12.  Moving the Per-User Forward Files ...........   57
   4.13.  Free Space ..................................   57
   4.14.  Maximum Message Size ........................   58
   4.15.  Privacy Flags ...............................   58
   4.16.  Send to Me Too ..............................   58
5.  THE WHOLE SCOOP ON THE CONFIGURATION FILE .........   58
   5.1.  R and S -- Rewriting Rules ...................   59
      5.1.1.  The left hand side ......................   60
      5.1.2.  The right hand side .....................   60
      5.1.3.  Semantics of rewriting rule sets ........   63
      5.1.4.  Ruleset hooks ...........................   64
         5.1.4.1.  check_relay ........................   65
         5.1.4.2.  check_mail .........................   65
         5.1.4.3.  check_rcpt .........................   65
         5.1.4.4.  check_data .........................   65
         5.1.4.5.  check_compat .......................   65
         5.1.4.6.  check_eoh ..........................   66
         5.1.4.7.  check_eom ..........................   66
         5.1.4.8.  check_etrn .........................   66
         5.1.4.9.  check_expn .........................   67
         5.1.4.10.  check_vrfy ........................   67
         5.1.4.11.  trust_auth ........................   67
         5.1.4.12.  tls_client ........................   67
         5.1.4.13.  tls_server ........................   67
         5.1.4.14.  tls_rcpt ..........................   67
         5.1.4.15.  srv_features ......................   68
         5.1.4.16.  try_tls ...........................   69










Sendmail Installation and Operation Guide           SMM:08-5


         5.1.4.17.  authinfo ..........................   69
         5.1.4.18.  queuegroup ........................   70
         5.1.4.19.  greet_pause .......................   70
      5.1.5.  IPC mailers .............................   71
   5.2.  D -- Define Macro ............................   71
   5.3.  C and F -- Define Classes ....................   83
   5.4.  M -- Define Mailer ...........................   85
   5.5.  H -- Define Header ...........................   94
   5.6.  O -- Set Option ..............................   95
   5.7.  P -- Precedence Definitions ..................  127
   5.8.  V -- Configuration Version Level .............  127
   5.9.  K -- Key File Declaration ....................  129
   5.10.  Q -- Queue Group Declaration ................  142
   5.11.  X -- Mail Filter (Milter) Definitions .......  144
   5.12.  The User Database ...........................  145
      5.12.1.  Structure of the user database .........  145
      5.12.2.  User database semantics ................  147
      5.12.3.  Creating the database[23] ..............  147
6.  OTHER CONFIGURATION ...............................  148
   6.1.  Parameters in devtools/OS/$oscf ..............  148
   6.2.  Parameters in sendmail/conf.h ................  150
   6.3.  Configuration in sendmail/conf.c .............  154
      6.3.1.  Built-in Header Semantics ...............  154
      6.3.2.  Restricting Use of Email ................  157
      6.3.3.  New Database Map Classes ................  158
      6.3.4.  Queueing Function .......................  158
      6.3.5.  Refusing Incoming SMTP Connections ......  159
      6.3.6.  Load Average Computation ................  159
   6.4.  Configuration in sendmail/daemon.c ...........  160
   6.5.  LDAP .........................................  160
      6.5.1.  LDAP Recursion ..........................  160
         6.5.1.1.  Example ............................  161
   6.6.  STARTTLS .....................................  162
      6.6.1.  Certificates for STARTTLS ...............  162
      6.6.2.  PRNG for STARTTLS .......................  163
   6.7.   Encoding  of  STARTTLS  and  AUTH  related
      Macros ..........................................  163
7.  ACKNOWLEDGEMENTS ..................................  164
Appendix A.  COMMAND LINE FLAGS .......................  166
Appendix B.  QUEUE FILE FORMATS .......................  170
Appendix C.  SUMMARY OF SUPPORT FILES .................  174






















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