1 .\" Copyright (c) 1998-2005 Sendmail, Inc. and its suppliers.
2 .\" All rights reserved.
3 .\" Copyright (c) 1983, 1995 Eric P. Allman. All rights reserved.
4 .\" Copyright (c) 1983, 1993
5 .\" The Regents of the University of California. All rights reserved.
7 .\" By using this file, you agree to the terms and conditions set
8 .\" forth in the LICENSE file which can be found at the top level of
9 .\" the sendmail distribution.
12 .\" $Id: op.me,v 8.749 2012/03/02 22:37:11 ca Exp $
14 .\" eqn op.me | pic | troff -me
16 .\" Define \(sc if not defined (for text output)
18 .if !c \(sc .char \(sc S
20 .\" Define \(dg as "*" for text output and create a new .DG macro
21 .\" which describes the symbol.
37 .\" Define \(dd as "#" for text output and create a new .DD macro
38 .\" which describes the symbol.
51 .eh 'SMM:08-%''Sendmail Installation and Operation Guide'
52 .oh 'Sendmail Installation and Operation Guide''SMM:08-%'
53 .\" SD is lib if sendmail is installed in /usr/lib, sbin if in /usr/sbin
55 .\" SB is bin if newaliases/mailq are installed in /usr/bin, ucb if in /usr/ucb
74 .b SENDMAIL\u\s-6TM\s0\d
77 .b "INSTALLATION AND OPERATION GUIDE"
80 This documentation is under modification.
93 .Ve $Revision: 8.749 $
96 For Sendmail Version 8.14
99 Sendmail is a trademark of Sendmail, Inc.
100 US Patent Numbers 6865671, 6986037.
104 .i Sendmail \u\s-2TM\s0\d
105 implements a general purpose internetwork mail routing facility
108 It is not tied to any one transport protocol \*-
109 its function may be likened to a crossbar switch,
110 relaying messages from one domain into another.
112 it can do a limited amount of message header editing
113 to put the message into a format that is appropriate
114 for the receiving domain.
115 All of this is done under the control of a configuration file.
117 Due to the requirements of flexibility
120 the configuration file can seem somewhat unapproachable.
121 However, there are only a few basic configurations
123 for which standard configuration files have been supplied.
124 Most other configurations
125 can be built by adjusting an existing configuration file
130 RFC 821 (Simple Mail Transport Protocol),
131 RFC 822 (Internet Mail Headers Format),
132 RFC 974 (MX routing),
133 RFC 1123 (Internet Host Requirements),
134 RFC 1413 (Identification server),
135 RFC 1652 (SMTP 8BITMIME Extension),
136 RFC 1869 (SMTP Service Extensions),
137 RFC 1870 (SMTP SIZE Extension),
138 RFC 1891 (SMTP Delivery Status Notifications),
139 RFC 1892 (Multipart/Report),
140 RFC 1893 (Enhanced Mail System Status Codes),
141 RFC 1894 (Delivery Status Notifications),
142 RFC 1985 (SMTP Service Extension for Remote Message Queue Starting),
143 RFC 2033 (Local Message Transmission Protocol),
144 RFC 2034 (SMTP Service Extension for Returning Enhanced Error Codes),
146 RFC 2476 (Message Submission),
147 RFC 2487 (SMTP Service Extension for Secure SMTP over TLS),
148 RFC 2554 (SMTP Service Extension for Authentication),
149 RFC 2821 (Simple Mail Transfer Protocol),
150 RFC 2822 (Internet Message Format),
151 RFC 2852 (Deliver By SMTP Service Extension),
153 RFC 2920 (SMTP Service Extension for Command Pipelining).
156 is designed to work in a wider world,
157 in many cases it can be configured to exceed these protocols.
158 These cases are described herein.
163 without the need for monitoring,
164 it has a number of features
165 that may be used to monitor or adjust the operation
166 under unusual circumstances.
167 These features are described.
169 Section one describes how to do a basic
173 explains the day-to-day information you should know
174 to maintain your mail system.
175 If you have a relatively normal site,
176 these two sections should contain sufficient information
181 has information regarding the command line arguments.
183 describes some parameters that may be safely tweaked.
185 contains the nitty-gritty information about the configuration
187 This section is for masochists
188 and people who must write their own configuration file.
190 describes configuration that can be done at compile time.
191 The appendixes give a brief
192 but detailed explanation of a number of features
193 not described in the rest of the paper.
195 .sh 1 "BASIC INSTALLATION"
197 There are two basic steps to installing
199 First, you have to compile and install the binary.
202 has already been ported to your operating system
203 that should be simple.
204 Second, you must build a run-time configuration file.
207 reads when it starts up
208 that describes the mailers it knows about,
209 how to parse addresses,
210 how to rewrite the message header,
211 and the settings of various options.
212 Although the configuration file can be quite complex,
213 a configuration can usually be built
214 using an M4-based configuration language.
215 Assuming you have the standard
219 for further information.
221 The remainder of this section will describe the installation of
223 assuming you can use one of the existing configurations
224 and that the standard installation parameters are acceptable.
225 All pathnames and examples
226 are given from the root of the
230 .i /usr/src/usr.\*(SD/sendmail
231 on 4.4BSD-based systems.
233 Continue with the next section if you need/want to compile
236 If you have a running binary already on your system,
237 you should probably skip to section 1.2.
238 .sh 2 "Compiling Sendmail"
253 This will leave the binary in an appropriately named subdirectory,
256 It works for multiple object versions
257 compiled out of the same directory.
258 .sh 3 "Tweaking the Build Invocation"
260 You can give parameters on the
263 In most cases these are only used when the
265 directory is first created.
266 To restart from scratch, use
268 These commands include:
270 .ip "\-L \fIlibdirs\fP"
271 A list of directories to search for libraries.
272 .ip "\-I \fIincdirs\fP"
273 A list of directories to search for include files.
274 .ip "\-E \fIenvar\fP=\fIvalue\fP"
275 Set an environment variable to an indicated
282 .ip "\-f \fIsiteconfig\fP"
283 Read the indicated site configuration file.
284 If this parameter is not specified,
289 .i $BUILDTOOLS/Site/site.$oscf.m4
291 .i $BUILDTOOLS/Site/site.config.m4 ,
292 where $BUILDTOOLS is normally
294 and $oscf is the same name as used on the
297 See below for a description of the site configuration file.
299 Skip auto-configuration.
301 will avoid auto-detecting libraries if this is set.
302 All libraries and map definitions must be specified
303 in the site configuration file.
305 Most other parameters are passed to the
307 program; for details see
308 .i $BUILDTOOLS/README .
309 .sh 3 "Creating a Site Configuration File"
312 (This section is not yet complete.
313 For now, see the file devtools/README for details.)
314 See sendmail/README for various compilation flags that can be set.
315 .sh 3 "Tweaking the Makefile"
317 .\" .b "XXX This should all be in the Site Configuration File section."
319 supports two different formats
320 for the local (on disk) version of databases,
324 At least one of these should be defined if at all possible.
327 The ``new DBM'' format,
328 available on nearly all systems around today.
329 This was the preferred format prior to 4.4BSD.
330 It allows such complex things as multiple databases
331 and closing a currently open database.
333 The Berkeley DB package.
334 If you have this, use it.
337 multiple open databases,
338 real in-memory caching,
340 You can define this in conjunction with
343 old alias databases are read,
344 but when a new database is created it will be in NEWDB format.
346 if you have NEWDB, NDBM, and NIS defined,
347 and if the alias file name includes the substring
350 will create both new and old versions of the alias file
354 This is required because the Sun NIS/YP system
355 reads the DBM version of the alias file.
359 If neither of these are defined,
361 reads the alias file into memory on every invocation.
362 This can be slow and should be avoided.
363 There are also several methods for remote database access:
365 Lightweight Directory Access Protocol.
367 Sun's Network Information Services (formerly YP).
371 NeXT's NetInfo service.
373 Hesiod service (from Athena).
375 Other compilation flags are set in
377 and should be predefined for you
378 unless you are porting to a new environment.
381 .sh 3 "Compilation and installation"
383 After making the local system configuration described above,
384 You should be able to compile and install the system.
387 is the best approach on most systems:
393 to create a custom Makefile for your environment.
395 If you are installing in the standard places,
396 you should be able to install using
400 This should install the binary in
402 and create links from
403 /usr/\*(SB/newaliases
408 On most systems it will also format and install man pages.
409 Notice: as of version 8.12
411 will no longer be installed set-user-ID root by default.
412 If you really want to use the old method, you can specify it as target:
414 \&./Build install-set-user-id
416 .sh 2 "Configuration Files"
419 cannot operate without a configuration file.
420 The configuration defines the mail delivery mechanisms understood at this site,
422 how to forward email to remote mail systems,
423 and a number of tuning parameters.
424 This configuration file is detailed
425 in the later portion of this document.
429 configuration can be daunting at first.
430 The world is complex,
431 and the mail configuration reflects that.
432 The distribution includes an m4-based configuration package
433 that hides a lot of the complexity.
438 Our configuration files are processed by
440 to facilitate local customization;
445 distribution directory
446 contains the source files.
447 This directory contains several subdirectories:
450 Both site-dependent and site-independent descriptions of hosts.
451 These can be literal host names
454 when the hosts are gateways
455 or more general descriptions
457 .q "generic-solaris2.mc"
458 as a general description of an SMTP-connected host
462 (``M4 Configuration'')
463 are the input descriptions;
464 the output is in the corresponding
467 The general structure of these files is described below.
469 Site-dependent subdomain descriptions.
470 These are tied to the way your organization wants to do addressing.
472 .b domain/CS.Berkeley.EDU.m4
473 is our description for hosts in the CS.Berkeley.EDU subdomain.
474 These are referenced using the
481 Definitions of specific features that some particular host in your site
483 These are referenced using the
487 An example feature is
491 to read an /etc/mail/local-host-names file on startup
492 to find the set of local names).
494 Local hacks, referenced using the
499 The point of having them here is to make it clear that they smell.
503 include files that have information common to all configuration files.
504 This can be thought of as a
508 Definitions of mailers,
513 The mailer types that are known in this distribution are
519 For example, to include support for the UUCP-based mailers,
523 Definitions describing various operating system environments
524 (such as the location of support files).
525 These are referenced using the
530 Shell files used by the
533 You shouldn't have to mess with these.
535 Local UUCP connectivity information.
536 This directory has been supplanted by the mailertable feature;
537 any new configurations should use that feature to do UUCP
539 The use of this directory is deprecated.
541 If you are in a new domain
543 you will probably want to create a
545 file for your domain.
546 This consists primarily of relay definitions
547 and features you want enabled site-wide:
548 for example, Berkeley's domain definition
552 These are specific to Berkeley,
553 and should be fully-qualified internet-style domain names.
554 Please check to make certain they are reasonable for your domain.
556 Subdomains at Berkeley are also represented in the
562 is the Computer Science subdomain,
564 is the Electrical Engineering and Computer Sciences subdomain,
567 is the Sequoia 2000 subdomain.
568 You will probably have to add an entry to this directory
569 to be appropriate for your domain.
571 You will have to use or create
575 subdirectory for your hosts.
576 This is detailed in the
579 .sh 2 "Details of Installation Files"
581 This subsection describes the files that
585 .sh 3 "/usr/\*(SD/sendmail"
589 is located in /usr/\*(SD\**.
593 on 4.4BSD and newer systems;
594 many systems install it in
596 I understand it is in /usr/ucblib
597 on System V Release 4.
599 It should be set-group-ID smmsp as described in
601 For security reasons,
602 /, /usr, and /usr/\*(SD
603 should be owned by root, mode 0755\**.
605 \**Some vendors ship them owned by bin;
606 this creates a security hole that is not actually related to
608 Other important directories that should have restrictive ownerships
610 /bin, /usr/bin, /etc, /etc/mail, /usr/etc, /lib, and /usr/lib.
612 .sh 3 "/etc/mail/sendmail.cf"
614 This is the main configuration file for
617 \**Actually, the pathname varies depending on the operating system;
618 /etc/mail is the preferred directory.
619 Some older systems install it in
620 .b /usr/lib/sendmail.cf ,
621 and I've also seen it in
623 If you want to move this file,
624 add -D_PATH_SENDMAILCF=\e"/file/name\e"
625 to the flags passed to the C compiler.
626 Moving this file is not recommended:
627 other programs and scripts know of this location.
629 This is one of the two non-library file names compiled into
631 the other is /etc/mail/submit.cf.
633 \**The system libraries can reference other files;
634 in particular, system library subroutines that
636 calls probably reference
639 .i /etc/resolv.conf .
642 The configuration file is normally created
643 using the distribution files described above.
644 If you have a particularly unusual system configuration
645 you may need to create a special version.
646 The format of this file is detailed in later sections
648 .sh 3 "/etc/mail/submit.cf"
650 This is the configuration file for
652 when it is used for initial mail submission, in which case
653 it is also called ``Mail Submission Program'' (MSP)
654 in contrast to ``Mail Transfer Agent'' (MTA).
655 Starting with version 8.12,
657 uses one of two different configuration files based on its operation mode
661 For initial mail submission, i.e., if one of the options
667 is specified, submit.cf is used (if available),
668 for other operations sendmail.cf is used.
669 Details can be found in
670 .i sendmail/SECURITY .
671 submit.cf is shipped with sendmail (in cf/cf/) and is installed by default.
672 If changes to the configuration need to be made, start with
673 cf/cf/submit.mc and follow the instruction in cf/README.
674 .sh 3 "/usr/\*(SB/newaliases"
678 command should just be a link to
681 rm \-f /usr/\*(SB/newaliases
682 ln \-s /usr/\*(SD/sendmail /usr/\*(SB/newaliases
684 This can be installed in whatever search path you prefer
686 .sh 3 "/usr/\*(SB/hoststat"
690 command should just be a link to
692 in a fashion similar to
694 This command lists the status of the last mail transaction
695 with all remote hosts. The
697 flag will prevent the status display from being truncated.
698 It functions only when the
699 .b HostStatusDirectory
701 .sh 3 "/usr/\*(SB/purgestat"
703 This command is also a link to
705 It flushes expired (Timeout.hoststatus) information that is stored in the
706 .b HostStatusDirectory
708 .sh 3 "/var/spool/mqueue"
712 should be created to hold the mail queue.
713 This directory should be mode 0700
716 The actual path of this directory
722 To use multiple queues,
723 supply a value ending with an asterisk.
725 .i /var/spool/mqueue/qd*
726 will use all of the directories or symbolic links to directories
727 beginning with `qd' in
729 as queue directories.
730 Do not change the queue directory structure
731 while sendmail is running.
733 If these directories have subdirectories or symbolic links to directories
734 named `qf', `df', and `xf', then these will be used for the different
736 That is, the data files are stored in the `df' subdirectory,
737 the transcript files are stored in the `xf' subdirectory, and
738 all others are stored in the `qf' subdirectory.
740 If shared memory support is compiled in,
742 stores the available diskspace in a shared memory segment
743 to make the values readily available to all children without
744 incurring system overhead.
745 In this case, only the daemon updates the data;
746 i.e., the sendmail daemon creates the shared memory segment
747 and deletes it if it is terminated.
750 must have been compiled with support for shared memory
755 Notice: do not use the same key for
757 invocations with different queue directories
758 or different queue group declarations.
759 Access to shared memory is not controlled by locks,
760 i.e., there is a race condition when data in the shared memory is updated.
761 However, since operation of
763 does not rely on the data in the shared memory, this does not negatively
764 influence the behavior.
765 .sh 3 "/var/spool/clientmqueue"
768 .i /var/spool/clientmqueue
769 should be created to hold the mail queue.
770 This directory should be mode 0770
771 and owned by user smmsp, group smmsp.
773 The actual path of this directory
779 .sh 3 "/var/spool/mqueue/.hoststat"
781 This is a typical value for the
782 .b HostStatusDirectory
784 containing one file per host
785 that this sendmail has chatted with recently.
786 It is normally a subdirectory of
788 .sh 3 "/etc/mail/aliases*"
790 The system aliases are held in
791 .q /etc/mail/aliases .
794 which includes some aliases which
798 cp sendmail/aliases /etc/mail/aliases
799 .i "edit /etc/mail/aliases"
801 You should extend this file with any aliases that are apropos to your system.
805 looks at a database version of the files,
807 .q /etc/mail/aliases.dir
809 .q /etc/mail/aliases.pag
811 .q /etc/mail/aliases.db
812 depending on which database package you are using.
813 The actual path of this file
820 The permissions of the alias file and the database versions
821 should be 0640 to prevent local denial of service attacks
822 as explained in the top level
824 in the sendmail distribution.
825 If the permissions 0640 are used, be sure that only trusted users belong
826 to the group assigned to those files. Otherwise, files should not even
828 .sh 3 "/etc/rc or /etc/init.d/sendmail"
830 It will be necessary to start up the
832 daemon when your system reboots.
833 This daemon performs two functions:
834 it listens on the SMTP socket for connections
835 (to receive mail from a remote system)
836 and it processes the queue periodically
837 to insure that mail gets delivered when hosts come up.
839 If necessary, add the following lines to
844 in the area where it is starting up the daemons
845 on a BSD-base system,
846 or on a System-V-based system
847 in one of the startup files, typically
848 .q /etc/init.d/sendmail :
850 if [ \-f /usr/\*(SD/sendmail \-a \-f /etc/mail/sendmail.cf ]; then
851 (cd /var/spool/mqueue; rm \-f xf*)
852 /usr/\*(SD/sendmail \-bd \-q30m &
853 echo \-n ' sendmail' >/dev/console
860 commands insure that all transcript files have been removed;
861 extraneous transcript files may be left around
862 if the system goes down in the middle of processing a message.
863 The line that actually invokes
867 causes it to listen on the SMTP port,
870 causes it to run the queue every half hour.
872 Some people use a more complex startup script,
873 removing zero length qf/hf/Qf files and df files for which there is no
875 Note this is not advisable.
876 For example, see Figure 1
877 for an example of a complex script which does this clean up.
881 # remove zero length qf/hf/Qf files
882 for qffile in qf* hf* Qf*
888 echo \-n " <zero: $qffile>" > /dev/console
893 # rename tf files to be qf if the qf does not exist
896 qffile=`echo $tffile | sed 's/t/q/'`
897 if [ \-r $tffile \-a ! \-f $qffile ]
899 echo \-n " <recovering: $tffile>" > /dev/console
904 echo \-n " <extra: $tffile>" > /dev/console
909 # remove df files with no corresponding qf/hf/Qf files
912 qffile=`echo $dffile | sed 's/d/q/'`
913 hffile=`echo $dffile | sed 's/d/h/'`
914 Qffile=`echo $dffile | sed 's/d/Q/'`
915 if [ \-r $dffile \-a ! \-f $qffile \-a ! \-f $hffile \-a ! \-f $Qffile ]
917 echo \-n " <incomplete: $dffile>" > /dev/console
918 mv $dffile `echo $dffile | sed 's/d/D/'`
921 # announce files that have been saved during disaster recovery
922 for xffile in [A-Z]f*
926 echo \-n " <panic: $xffile>" > /dev/console
931 Figure 1 \(em A complex startup script
934 .sh 3 "/etc/mail/helpfile"
936 This is the help file used by the SMTP
939 It should be copied from
940 .q sendmail/helpfile :
942 cp sendmail/helpfile /etc/mail/helpfile
944 The actual path of this file
950 .sh 3 "/etc/mail/statistics"
952 If you wish to collect statistics
953 about your mail traffic,
954 you should create the file
955 .q /etc/mail/statistics :
957 cp /dev/null /etc/mail/statistics
958 chmod 0600 /etc/mail/statistics
960 This file does not grow.
961 It is printed with the program
962 .q mailstats/mailstats.c.
963 The actual path of this file
969 .sh 3 "/usr/\*(SB/mailq"
980 will print the contents of the mail queue;
982 This should be a link to /usr/\*(SD/sendmail.
986 stores its current pid in the file specified by the
988 option (default is _PATH_SENDMAILPID).
992 (which defaults to 0600) as
993 the permissions of that file
994 to prevent local denial of service attacks
995 as explained in the top level
997 in the sendmail distribution.
998 If the file already exists, then it might be necessary to
999 change the permissions accordingly, e.g.,
1001 chmod 0600 /var/run/sendmail.pid
1003 Note that as of version 8.13, this file is unlinked when
1006 As a result of this change, a script such as the following,
1007 which may have worked prior to 8.13, will no longer work:
1009 # stop & start sendmail
1010 PIDFILE=/var/run/sendmail.pid
1011 kill `head -1 $PIDFILE`
1014 because it assumes that the pidfile will still exist even
1015 after killing the process to which it refers.
1016 Below is a script which will work correctly
1017 on both newer and older versions:
1019 # stop & start sendmail
1020 PIDFILE=/var/run/sendmail.pid
1021 pid=`head -1 $PIDFILE`
1022 cmd=`tail -1 $PIDFILE`
1026 This is just an example script, it does not perform any error checks,
1027 e.g., whether the pidfile exists at all.
1030 To prevent local denial of service attacks
1031 as explained in the top level
1033 in the sendmail distribution,
1034 the permissions of map files created by
1037 The use of 0640 implies that only trusted users belong to the group
1038 assigned to those files.
1039 If those files already exist, then it might be necessary to
1040 change the permissions accordingly, e.g.,
1043 chmod 0640 *.db *.pag *.dir
1045 .sh 1 "NORMAL OPERATIONS"
1046 .sh 2 "The System Log"
1048 The system log is supported by the
1053 are logged under the
1057 \**Except on Ultrix,
1058 which does not support facilities in the syslog.
1062 Each line in the system log
1063 consists of a timestamp,
1064 the name of the machine that generated it
1065 (for logging from several machines
1066 over the local area network),
1071 \**This format may vary slightly if your vendor has changed
1074 Most messages are a sequence of
1080 The two most common lines are logged when a message is processed.
1081 The first logs the receipt of a message;
1082 there will be exactly one of these per message.
1083 Some fields may be omitted if they do not contain interesting information.
1086 The envelope sender address.
1088 The size of the message in bytes.
1090 The class (i.e., numeric precedence) of the message.
1092 The initial message priority (used for queue sorting).
1094 The number of envelope recipients for this message
1095 (after aliasing and forwarding).
1097 The message id of the message (from the header).
1099 The message body type (7BIT or 8BITMIME),
1100 as determined from the envelope.
1102 The protocol used to receive this message (e.g., ESMTP or UUCP)
1104 The daemon name from the
1105 .b DaemonPortOptions
1108 The machine from which it was received.
1110 There is also one line logged per delivery attempt
1111 (so there can be several per message if delivery is deferred
1112 or there are multiple recipients).
1115 A comma-separated list of the recipients to this mailer.
1117 The ``controlling user'', that is, the name of the user
1118 whose credentials we use for delivery.
1120 The total delay between the time this message was received
1121 and the current delivery attempt.
1123 The amount of time needed in this delivery attempt
1124 (normally indicative of the speed of the connection).
1126 The name of the mailer used to deliver to this recipient.
1128 The name of the host that actually accepted (or rejected) this recipient.
1130 The enhanced error code (RFC 2034) if available.
1132 The delivery status.
1134 Not all fields are present in all messages;
1135 for example, the relay is usually not listed for local deliveries.
1140 or an equivalent installed,
1141 you will be able to do logging.
1142 There is a large amount of information that can be logged.
1143 The log is arranged as a succession of levels.
1145 only extremely strange situations are logged.
1146 At the highest level,
1147 even the most mundane and uninteresting events
1148 are recorded for posterity.
1150 log levels under ten
1151 are considered generally
1154 are reserved for debugging purposes.
1155 Levels from 11\-64 are reserved for verbose information
1156 that some sites might want.
1158 A complete description of the log levels
1159 is given in section ``Log Level''.
1160 .sh 2 "Dumping State"
1164 to log a dump of the open files
1165 and the connection cache
1169 The results are logged at
1172 .sh 2 "The Mail Queues"
1174 Mail messages may either be delivered immediately or be held for later
1176 Held messages are placed into a holding directory called a mail queue.
1178 A mail message may be queued for these reasons:
1180 If a mail message is temporarily undeliverable, it is queued
1181 and delivery is attempted later.
1182 If the message is addressed to multiple recipients, it is queued
1183 only for those recipients to whom delivery is not immediately possible.
1185 If the SuperSafe option is set to true,
1186 all mail messages are queued while delivery is attempted.
1188 If the DeliveryMode option is set to queue-only or defer,
1189 all mail is queued, and no immediate delivery is attempted.
1191 If the load average becomes higher than the value of the QueueLA option
1196 option divided by the difference in the current load average and the
1199 is less than the priority of the message,
1200 messages are queued rather than immediately delivered.
1202 One or more addresses are marked as expensive and delivery is postponed
1203 until the next queue run or one or more address are marked as held via
1204 mailer which uses the hold mailer flag.
1206 The mail message has been marked as quarantined via a mail filter or
1209 .sh 3 "Queue Groups and Queue Directories"
1211 There are one or more mail queues.
1212 Each mail queue belongs to a queue group.
1213 There is always a default queue group that is called ``mqueue''
1214 (which is where messages go by default unless otherwise specified).
1215 The directory or directories which comprise the default queue group
1216 are specified by the QueueDirectory option.
1217 There are zero or more
1218 additional named queue groups declared using the
1220 command in the configuration file.
1222 By default, a queued message is placed in the queue group
1223 associated with the first recipient in the recipient list.
1224 A recipient address is mapped to a queue group as follows.
1225 First, if there is a ruleset called ``queuegroup'',
1226 and if this ruleset maps the address to a queue group name,
1227 then that queue group is chosen.
1228 That is, the argument for the ruleset is the recipient address
1229 and the result should be
1231 followed by the name of a queue group.
1232 Otherwise, if the mailer associated with the address specifies
1233 a queue group, then that queue group is chosen.
1234 Otherwise, the default queue group is chosen.
1236 A message with multiple recipients will be split
1237 if different queue groups are chosen
1238 by the mapping of recipients to queue groups.
1240 When a message is placed in a queue group, and the queue group has
1241 more than one queue, a queue is selected randomly.
1243 If a message with multiple recipients is placed into a queue group
1244 with the 'r' option (maximum number of recipients per message)
1245 set to a positive value
1247 and if there are more than
1250 in the message, then the message will be split into multiple messages,
1251 each of which have at most
1255 Notice: if multiple queue groups are used, do
1257 move queue files around, e.g., into a different queue directory.
1258 This may have weird effects and can cause mail not to be delivered.
1259 Queue files and directories should be treated as opaque
1260 and should not be manipulated directly.
1264 has two different ways to process the queue(s).
1265 The first one is to start queue runners after certain intervals
1266 (``normal'' queue runners),
1267 the second one is to keep queue runner processes around
1268 (``persistent'' queue runners).
1269 How to select either of these types is discussed in the appendix
1270 ``COMMAND LINE FLAGS''.
1271 Persistent queue runners have the advantage that no new processes
1272 need to be spawned at certain intervals; they just sleep for
1273 a specified time after they finished a queue run.
1274 Another advantage of persistent queue runners is that only one process
1275 belonging to a workgroup (a workgroup is a set of queue groups)
1276 collects the data for a queue run
1277 and then multiple queue runner may go ahead using that data.
1278 This can significantly reduce the disk I/O necessary to read the
1279 queue files compared to starting multiple queue runners directly.
1280 Their disadvantage is that a new queue run is only started
1281 after all queue runners belonging to a group finished their tasks.
1282 In case one of the queue runners tries delivery to a slow recipient site
1283 at the end of a queue run, the next queue run may be substantially delayed.
1284 In general this should be smoothed out due to the distribution of
1285 those slow jobs, however, for sites with small number of
1286 queue entries this might introduce noticable delays.
1287 In general, persistent queue runners are only useful for
1288 sites with big queues.
1289 .sh 3 "Manual Intervention"
1291 Under normal conditions the mail queue will be processed transparently.
1292 However, you may find that manual intervention is sometimes necessary.
1294 if a major host is down for a period of time
1295 the queue may become clogged.
1298 ought to recover gracefully when the host comes up,
1299 you may find performance unacceptably bad in the meantime.
1300 In that case you want to check the content of the queue
1301 and manipulate it as explained in the next two sections.
1302 .sh 3 "Printing the queue"
1304 The contents of the queue(s) can be printed
1308 (or by specifying the
1315 This will produce a listing of the queue id's,
1316 the size of the message,
1317 the date the message entered the queue,
1318 and the sender and recipients.
1319 If shared memory support is compiled in,
1322 can be used to print the number of entries in the queue(s),
1323 provided a process updates the data.
1324 However, as explained earlier, the output might be slightly wrong,
1325 since access to the shared memory is not locked.
1327 ``unknown number of entries''
1329 The internal counters are updated after each queue run
1330 to the correct value again.
1331 .sh 3 "Forcing the queue"
1334 should run the queue automatically at intervals.
1335 When using multiple queues,
1336 a separate process will by default be created to
1337 run each of the queues
1338 unless the queue run is initiated by a user
1339 with the verbose flag.
1340 The algorithm is to read and sort the queue,
1341 and then to attempt to process all jobs in order.
1342 When it attempts to run the job,
1344 first checks to see if the job is locked.
1345 If so, it ignores the job.
1347 There is no attempt to insure that only one queue processor
1349 since there is no guarantee that a job cannot take forever
1353 does include heuristics to try to abort jobs
1354 that are taking absurd amounts of time;
1355 technically, this violates RFC 821, but is blessed by RFC 1123).
1356 Due to the locking algorithm,
1357 it is impossible for one job to freeze the entire queue.
1359 an uncooperative recipient host
1360 or a program recipient
1362 can accumulate many processes in your system.
1364 there is no completely general way to solve this.
1367 you may find that a major host going down
1368 for a couple of days
1369 may create a prohibitively large queue.
1372 spending an inordinate amount of time
1374 This situation can be fixed by moving the queue to a temporary place
1375 and creating a new queue.
1376 The old queue can be run later when the offending host returns to service.
1379 it is acceptable to move the entire queue directory:
1382 mv mqueue omqueue; mkdir mqueue; chmod 0700 mqueue
1384 You should then kill the existing daemon
1385 (since it will still be processing in the old queue directory)
1386 and create a new daemon.
1388 To run the old mail queue, issue the following command:
1390 /usr/\*(SD/sendmail \-C /etc/mail/queue.cf \-q
1394 flag specifies an alternate configuration file
1396 which should refer to the moved queue directory
1398 O QueueDirectory=/var/spool/omqueue
1402 flag says to just run every job in the queue.
1403 You can also specify the moved queue directory on the command line
1405 /usr/\*(SD/sendmail \-oQ/var/spool/omqueue \-q
1407 but this requires that you do not have
1408 queue groups in the configuration file,
1409 because those are not subdirectories of the moved directory.
1410 See the section about ``Queue Group Declaration'' for details;
1411 you most likely need a different configuration file to correctly deal
1413 However, a proper configuration of queue groups should avoid
1414 filling up queue directories, so you shouldn't run into
1416 If you have a tendency toward voyeurism,
1419 flag to watch what is going on.
1421 When the queue is finally emptied,
1422 you can remove the directory:
1424 rmdir /var/spool/omqueue
1426 .sh 3 "Quarantined Queue Items"
1428 It is possible to "quarantine" mail messages,
1429 otherwise known as envelopes.
1430 Envelopes (queue files) are stored but not considered for delivery or
1431 display unless the "quarantine" state of the envelope is undone or
1432 delivery or display of quarantined items is requested.
1433 Quarantined messages are tagged by using a different name for the queue
1434 file, 'hf' instead of 'qf', and by adding the quarantine reason to the
1437 Delivery or display of quarantined items can be requested using the
1443 Additionally, messages already in the queue can be quarantined or
1444 unquarantined using the new
1449 sendmail -Qreason -q[!][I|R|S][matchstring]
1451 Quarantines the normal queue items matching the criteria specified by the
1452 .b "-q[!][I|R|S][matchstring]"
1453 using the reason given on the
1458 sendmail -qQ -Q[reason] -q[!][I|R|S|Q][matchstring]
1460 Change the quarantine reason for the quarantined items matching the
1461 criteria specified by the
1462 .b "-q[!][I|R|S|Q][matchstring]"
1463 using the reason given on the
1466 If there is no reason,
1467 unquarantine the matching items and make them normal queue items.
1470 flag tells sendmail to operate on quarantined items instead of normal items.
1471 .sh 2 "Disk Based Connection Information"
1474 stores a large amount of information about each remote system it
1475 has connected to in memory. It is possible to preserve some
1476 of this information on disk as well, by using the
1477 .b HostStatusDirectory
1478 option, so that it may be shared between several invocations of
1480 This allows mail to be queued immediately or skipped during a queue run if
1481 there has been a recent failure in connecting to a remote machine.
1482 Note: information about a remote system is stored in a file
1483 whose pathname consists of the components of the hostname in reverse order.
1484 For example, the information for
1487 .b com./example./host .
1488 For top-level domains like
1490 this can create a large number of subdirectories
1491 which on some filesystems can exhaust some limits.
1492 Moreover, the performance of lookups in directory with thousands of entries
1493 can be fairly slow depending on the filesystem implementation.
1495 Additionally enabling
1496 .b SingleThreadDelivery
1497 has the added effect of single-threading mail delivery to a destination.
1498 This can be quite helpful
1499 if the remote machine is running an SMTP server that is easily overloaded
1500 or cannot accept more than a single connection at a time,
1501 but can cause some messages to be punted to a future queue run.
1504 hosts, so setting this because you have one machine on site
1505 that runs some software that is easily overrun
1506 can cause mail to other hosts to be slowed down.
1507 If this option is set,
1508 you probably want to set the
1510 option as well and run the queue fairly frequently;
1511 this way jobs that are skipped because another
1513 is talking to the same host will be tried again quickly
1514 rather than being delayed for a long time.
1516 The disk based host information is stored in a subdirectory of the
1521 \**This is the usual value of the
1522 .b HostStatusDirectory
1524 it can, of course, go anywhere you like in your filesystem.
1526 Removing this directory and its subdirectories has an effect similar to
1529 command and is completely safe.
1532 only removes expired (Timeout.hoststatus) data.
1533 The information in these directories can
1536 command, which will indicate the host name, the last access, and the
1537 status of that access.
1538 An asterisk in the left most column indicates that a
1540 process currently has the host locked for mail delivery.
1542 The disk based connection information is treated the same way as memory based
1543 connection information for the purpose of timeouts.
1544 By default, information about host failures is valid for 30 minutes.
1545 This can be adjusted with
1547 .b Timeout.hoststatus
1550 The connection information stored on disk may be expired at any time
1553 command or by invoking sendmail with the
1556 The connection information may be viewed with the
1558 command or by invoking sendmail with the
1561 .sh 2 "The Service Switch"
1563 The implementation of certain system services
1564 such as host and user name lookup
1565 is controlled by the service switch.
1566 If the host operating system supports such a switch,
1567 and sendmail knows about it,
1569 will use the native version.
1570 Ultrix, Solaris, and DEC OSF/1 are examples of such systems\**.
1572 \**HP-UX 10 has service switch support,
1573 but since the APIs are apparently not available in the libraries
1575 does not use the native service switch in this release.
1578 If the underlying operating system does not support a service switch
1579 (e.g., SunOS 4.X, HP-UX, BSD)
1582 will provide a stub implementation.
1584 .b ServiceSwitchFile
1585 option points to the name of a file that has the service definitions.
1586 Each line has the name of a service
1587 and the possible implementations of that service.
1588 For example, the file:
1595 to look for hosts in the Domain Name System first.
1596 If the requested host name is not found, it tries local files,
1597 and if that fails it tries NIS.
1598 Similarly, when looking for aliases
1599 it will try the local files first followed by NIS.
1603 must access MX records for correct operation, it will use
1604 DNS if it is configured in the
1605 .b ServiceSwitchFile
1611 will not avoid DNS lookups even if a host can be found
1614 Service switches are not completely integrated.
1615 For example, despite the fact that the host entry listed in the above example
1616 specifies to look in NIS,
1617 on SunOS this won't happen because the system implementation of
1618 .i gethostbyname \|(3)
1619 doesn't understand this.
1620 .sh 2 "The Alias Database"
1622 After recipient addresses are read from the SMTP connection
1624 they are parsed by ruleset 0,
1625 which must resolve to a
1631 If the flags selected by the
1638 part of the triple is looked up as the key
1639 (i.e., the left hand side)
1640 in the alias database.
1641 If there is a match, the address is deleted from the send queue
1642 and all addresses on the right hand side of the alias
1643 are added in place of the alias that was found.
1644 This is a recursive operation,
1645 so aliases found in the right hand side of the alias
1646 are similarly expanded.
1648 The alias database exists in two forms.
1650 maintained in the file
1651 .i /etc/mail/aliases.
1652 The aliases are of the form
1654 name: name1, name2, ...
1656 Only local names may be aliased;
1659 eric@prep.ai.MIT.EDU: eric@CS.Berkeley.EDU
1661 will not have the desired effect
1662 (except on prep.ai.MIT.EDU,
1663 and they probably don't want me)\**.
1665 \**Actually, any mailer that has the `A' mailer flag set
1666 will permit aliasing;
1667 this is normally limited to the local mailer.
1669 Aliases may be continued by starting any continuation lines
1670 with a space or a tab or by putting a backslash directly before
1672 Blank lines and lines beginning with a sharp sign
1677 The second form is processed by the
1682 package does not work.
1684 or the Berkeley DB library.
1685 This form is in the file
1686 .i /etc/mail/aliases.db
1689 .i /etc/mail/aliases.dir
1691 .i /etc/mail/aliases.pag
1693 This is the form that
1695 actually uses to resolve aliases.
1696 This technique is used to improve performance.
1698 The control of search order is actually set by the service switch.
1699 Essentially, the entry
1701 O AliasFile=switch:aliases
1703 is always added as the first alias entry;
1704 also, the first alias file name without a class
1708 will be used as the name of the file for a ``files'' entry
1709 in the aliases switch.
1710 For example, if the configuration file contains
1712 O AliasFile=/etc/mail/aliases
1714 and the service switch contains
1716 aliases nis files nisplus
1718 then aliases will first be searched in the NIS database,
1719 then in /etc/mail/aliases,
1720 then in the NIS+ database.
1725 For example, the specification:
1727 O AliasFile=/etc/mail/aliases
1728 O AliasFile=nis:mail.aliases@my.nis.domain
1730 will first search the /etc/mail/aliases file
1731 and then the map named
1735 Warning: if you build your own
1738 be sure to provide the
1742 to map upper case letters in the keys to lower case;
1743 otherwise, aliases with upper case letters in their names
1744 won't match incoming addresses.
1746 Additional flags can be added after the colon
1749 line \(em for example:
1751 O AliasFile=nis:\-N mail.aliases@my.nis.domain
1753 will search the appropriate NIS map and always include null bytes in the key.
1756 O AliasFile=nis:\-f mail.aliases@my.nis.domain
1758 will prevent sendmail from downcasing the key before the alias lookup.
1759 .sh 3 "Rebuilding the alias database"
1765 version of the database
1766 may be rebuilt explicitly by executing the command
1770 This is equivalent to giving
1776 /usr/\*(SD/sendmail \-bi
1779 If you have multiple aliases databases specified,
1782 flag rebuilds all the database types it understands
1783 (for example, it can rebuild NDBM databases but not NIS databases).
1784 .sh 3 "Potential problems"
1786 There are a number of problems that can occur
1787 with the alias database.
1788 They all result from a
1790 process accessing the DBM version
1791 while it is only partially built.
1792 This can happen under two circumstances:
1793 One process accesses the database
1794 while another process is rebuilding it,
1795 or the process rebuilding the database dies
1796 (due to being killed or a system crash)
1797 before completing the rebuild.
1799 Sendmail has three techniques to try to relieve these problems.
1800 First, it ignores interrupts while rebuilding the database;
1801 this avoids the problem of someone aborting the process
1802 leaving a partially rebuilt database.
1804 it locks the database source file during the rebuild \(em
1805 but that may not work over NFS or if the file is unwritable.
1807 at the end of the rebuild
1808 it adds an alias of the form
1812 (which is not normally legal).
1815 will access the database,
1816 it checks to insure that this entry exists\**.
1820 option is required in the configuration
1821 for this action to occur.
1822 This should normally be specified.
1826 If an error occurs on sending to a certain address,
1830 will look for an alias
1833 to receive the errors.
1834 This is typically useful
1836 where the submitter of the list
1837 has no control over the maintenance of the list itself;
1838 in this case the list maintainer would be the owner of the list.
1841 unix-wizards: eric@ucbarpa, wnj@monet, nosuchuser,
1843 owner-unix-wizards: unix-wizards-request
1844 unix-wizards-request: eric@ucbarpa
1848 to get the error that will occur
1849 when someone sends to
1851 due to the inclusion of
1855 List owners also cause the envelope sender address to be modified.
1856 The contents of the owner alias are used if they point to a single user,
1857 otherwise the name of the alias itself is used.
1858 For this reason, and to obey Internet conventions,
1861 address normally points at the
1863 address; this causes messages to go out with the typical Internet convention
1866 as the return address.
1867 .sh 2 "User Information Database"
1869 This option is deprecated, use virtusertable and genericstable instead
1872 If you have a version of
1874 with the user information database
1876 and you have specified one or more databases using the
1879 the databases will be searched for a
1882 If found, the mail will be sent to the specified address.
1883 .sh 2 "Per-User Forwarding (.forward Files)"
1885 As an alternative to the alias database,
1886 any user may put a file with the name
1888 in his or her home directory.
1889 If this file exists,
1891 redirects mail for that user
1892 to the list of addresses listed in the .forward file.
1893 Note that aliases are fully expanded before forward files are referenced.
1894 For example, if the home directory for user
1896 has a .forward file with contents:
1901 then any mail arriving for
1903 will be redirected to the specified accounts.
1905 Actually, the configuration file defines a sequence of filenames to check.
1906 By default, this is the user's .forward file,
1907 but can be defined to be more generally using the
1911 you will have to inform your user base of the change;
1912 \&.forward is pretty well incorporated into the collective subconscious.
1913 .sh 2 "Special Header Lines"
1915 Several header lines have special interpretations
1916 defined by the configuration file.
1917 Others have interpretations built into
1919 that cannot be changed without changing the code.
1920 These built-ins are described here.
1923 If errors occur anywhere during processing,
1924 this header will cause error messages to go to
1925 the listed addresses.
1926 This is intended for mailing lists.
1928 The Errors-To: header was created in the bad old days
1929 when UUCP didn't understand the distinction between an envelope and a header;
1930 this was a hack to provide what should now be passed
1931 as the envelope sender address.
1933 It is only used if the
1937 The Errors-To: header is officially deprecated
1938 and will go away in a future release.
1939 .sh 3 "Apparently-To:"
1941 RFC 822 requires at least one recipient field
1942 (To:, Cc:, or Bcc: line)
1944 If a message comes in with no recipients listed in the message
1947 will adjust the header based on the
1948 .q NoRecipientAction
1950 One of the possible actions is to add an
1952 header line for any recipients it is aware of.
1954 The Apparently-To: header is non-standard
1955 and is both deprecated and strongly discouraged.
1958 The Precedence: header can be used as a crude control of message priority.
1959 It tweaks the sort order in the queue
1960 and can be configured to change the message timeout values.
1961 The precedence of a message also controls how
1962 delivery status notifications (DSNs)
1963 are processed for that message.
1964 .sh 2 "IDENT Protocol Support"
1967 supports the IDENT protocol as defined in RFC 1413.
1968 Note that the RFC states
1969 a client should wait at least 30 seconds for a response.
1970 The default Timeout.ident is 5 seconds
1971 as many sites have adopted the practice of dropping IDENT queries.
1972 This has lead to delays processing mail.
1973 Although this enhances identification
1974 of the author of an email message
1975 by doing a ``call back'' to the originating system to include
1976 the owner of a particular TCP connection
1978 it is in no sense perfect;
1979 a determined forger can easily spoof the IDENT protocol.
1980 The following description is excerpted from RFC 1413:
1983 6. Security Considerations
1985 The information returned by this protocol is at most as trustworthy
1986 as the host providing it OR the organization operating the host. For
1987 example, a PC in an open lab has few if any controls on it to prevent
1988 a user from having this protocol return any identifier the user
1989 wants. Likewise, if the host has been compromised the information
1990 returned may be completely erroneous and misleading.
1992 The Identification Protocol is not intended as an authorization or
1993 access control protocol. At best, it provides some additional
1994 auditing information with respect to TCP connections. At worst, it
1995 can provide misleading, incorrect, or maliciously incorrect
1998 The use of the information returned by this protocol for other than
1999 auditing is strongly discouraged. Specifically, using Identification
2000 Protocol information to make access control decisions - either as the
2001 primary method (i.e., no other checks) or as an adjunct to other
2002 methods may result in a weakening of normal host security.
2004 An Identification server may reveal information about users,
2005 entities, objects or processes which might normally be considered
2006 private. An Identification server provides service which is a rough
2007 analog of the CallerID services provided by some phone companies and
2008 many of the same privacy considerations and arguments that apply to
2009 the CallerID service apply to Identification. If you wouldn't run a
2010 "finger" server due to privacy considerations you may not want to run
2014 In some cases your system may not work properly with IDENT support
2015 due to a bug in the TCP/IP implementation.
2016 The symptoms will be that for some hosts
2017 the SMTP connection will be closed
2019 If this is true or if you do not want to use IDENT,
2020 you should set the IDENT timeout to zero;
2021 this will disable the IDENT protocol.
2024 The complete list of arguments to
2026 is described in detail in Appendix A.
2027 Some important arguments are described here.
2028 .sh 2 "Queue Interval"
2030 The amount of time between forking a process
2031 to run through the queue is defined by the
2034 If you run with delivery mode set to
2038 this can be relatively large, since it will only be relevant
2039 when a host that was down comes back up.
2042 mode it should be relatively short,
2043 since it defines the maximum amount of time that a message
2044 may sit in the queue.
2045 (See also the MinQueueAge option.)
2047 RFC 1123 section 5.3.1.1 says that this value should be at least 30 minutes
2048 (although that probably doesn't make sense if you use ``queue-only'' mode).
2050 Notice: the meaning of the interval time depends on whether normal
2051 queue runners or persistent queue runners are used.
2052 For the former, it is the time between subsequent starts of a queue run.
2053 For the latter, it is the time sendmail waits after a persistent queue
2054 runner has finished its work to start the next one.
2055 Hence for persistent queue runners this interval should be very low,
2056 typically no more than two minutes.
2059 If you allow incoming mail over an IPC connection,
2060 you should have a daemon running.
2061 This should be set by your
2070 flag may be combined in one call:
2072 /usr/\*(SD/sendmail \-bd \-q30m
2075 An alternative approach is to invoke sendmail from
2079 flags to ask sendmail to speak SMTP on its standard input and output
2081 This works and allows you to wrap
2083 in a TCP wrapper program,
2084 but may be a bit slower since the configuration file
2085 has to be re-read on every message that comes in.
2086 If you do this, you still need to have a
2088 running to flush the queue:
2090 /usr/\*(SD/sendmail \-q30m
2092 .sh 2 "Forcing the Queue"
2094 In some cases you may find that the queue has gotten clogged for some reason.
2095 You can force a queue run
2098 flag (with no value).
2099 It is entertaining to use the
2102 when this is done to watch what happens:
2104 /usr/\*(SD/sendmail \-q \-v
2107 You can also limit the jobs to those with a particular queue identifier,
2108 recipient, sender, quarantine reason, or queue group
2109 using one of the queue modifiers.
2112 restricts the queue run to jobs that have the string
2114 somewhere in one of the recipient addresses.
2117 limits the run to particular senders,
2119 limits it to particular queue identifiers, and
2121 limits it to particular quarantined reasons and only operated on
2122 quarantined queue items, and
2124 limits it to a particular queue group.
2125 The named queue group will be run even if it is set to have 0 runners.
2126 You may also place an
2136 to indicate that jobs are limited to not including a particular queue
2137 identifier, recipient or sender.
2140 limits the queue run to jobs that do not have the string
2142 somewhere in one of the recipient addresses.
2143 Should you need to terminate the queue jobs currently active then a SIGTERM
2144 to the parent of the process (or processes) will cleanly stop the jobs.
2147 There are a fairly large number of debug flags
2150 Each debug flag has a category and a level.
2151 Higher levels increase the level of debugging activity;
2152 in most cases, this means to print out more information.
2153 The convention is that levels greater than nine are
2156 they print out so much information that you wouldn't normally
2157 want to see them except for debugging that particular piece of code.
2161 run a production sendmail server in debug mode.
2162 Many of the debug flags will result in debug output being sent over the
2163 SMTP channel unless the option
2166 This will confuse many mail programs.
2167 However, for testing purposes, it can be useful
2168 when sending mail manually via
2169 telnet to the port you are using while debugging.
2171 A debug category is either an integer, like 42,
2172 or a name, like ANSI.
2173 You can specify a range of numeric debug categories
2174 using the syntax 17-42.
2175 You can specify a set of named debug categories using
2182 are supported in these glob patterns.
2184 Debug flags are set using the
2189 .ta \w'debug-categories:M 'u
2190 debug-flag: \fB\-d\fP debug-list
2191 debug-list: debug-option [ , debug-option ]*
2192 debug-option: debug-categories [ . debug-level ]
2193 debug-categories: integer | integer \- integer | category-pattern
2194 category-pattern: [a-zA-Z_*?][a-zA-Z0-9_*?]*
2195 debug-level: integer
2197 where spaces are for reading ease only.
2200 \-d12 Set category 12 to level 1
2201 \-d12.3 Set category 12 to level 3
2202 \-d3\-17 Set categories 3 through 17 to level 1
2203 \-d3\-17.4 Set categories 3 through 17 to level 4
2204 \-dANSI Set category ANSI to level 1
2205 \-dsm_trace_*.3 Set all named categories matching sm_trace_* to level 3
2207 For a complete list of the available debug flags
2208 you will have to look at the code
2211 file in the sendmail distribution
2212 (they are too dynamic to keep this document up to date).
2213 For a list of named debug categories in the sendmail binary, use
2215 ident /usr/sbin/sendmail | grep Debug
2217 .sh 2 "Changing the Values of Options"
2219 Options can be overridden using the
2226 /usr/\*(SD/sendmail \-oT2m
2230 (timeout) option to two minutes
2232 the equivalent line using the long option name is
2234 /usr/\*(SD/sendmail -OTimeout.queuereturn=2m
2237 Some options have security implications.
2238 Sendmail allows you to set these,
2239 but relinquishes its set-user-ID or set-group-ID permissions thereafter\**.
2241 \**That is, it sets its effective uid to the real uid;
2242 thus, if you are executing as root,
2243 as from root's crontab file or during system startup
2244 the root permissions will still be honored.
2246 .sh 2 "Trying a Different Configuration File"
2248 An alternative configuration file
2249 can be specified using the
2253 /usr/\*(SD/sendmail \-Ctest.cf \-oQ/tmp/mqueue
2255 uses the configuration file
2257 instead of the default
2258 .i /etc/mail/sendmail.cf.
2264 in the current directory.
2267 gives up set-user-ID root permissions
2268 (if it has been installed set-user-ID root)
2269 when you use this flag, so it is common to use a publicly writable directory
2271 as the queue directory (QueueDirectory or Q option) while testing.
2272 .sh 2 "Logging Traffic"
2274 Many SMTP implementations do not fully implement the protocol.
2275 For example, some personal computer based SMTPs
2276 do not understand continuation lines in reply codes.
2277 These can be very hard to trace.
2278 If you suspect such a problem, you can set traffic logging using the
2283 /usr/\*(SD/sendmail \-X /tmp/traffic \-bd
2285 will log all traffic in the file
2288 This logs a lot of data very quickly and should
2291 during normal operations.
2292 After starting up such a daemon,
2293 force the errant implementation to send a message to your host.
2294 All message traffic in and out of
2296 including the incoming SMTP traffic,
2297 will be logged in this file.
2298 .sh 2 "Testing Configuration Files"
2300 When you build a configuration table,
2301 you can do a certain amount of testing
2311 sendmail \-bt \-Ctest.cf
2313 which would read the configuration file
2315 and enter test mode.
2317 you enter lines of the form:
2323 is the rewriting set you want to use
2326 is an address to apply the set to.
2327 Test mode shows you the steps it takes
2329 finally showing you the address it ends up with.
2330 You may use a comma separated list of rwsets
2331 for sequential application of rules to an input.
2334 3,1,21,4 monet:bollard
2336 first applies ruleset three to the input
2338 Ruleset one is then applied to the output of ruleset three,
2339 followed similarly by rulesets twenty-one and four.
2341 If you need more detail,
2342 you can also use the
2344 flag to turn on more debugging.
2347 sendmail \-bt \-d21.99
2349 turns on an incredible amount of information;
2350 a single word address
2351 is probably going to print out several pages worth of information.
2353 You should be warned that internally,
2355 applies ruleset 3 to all addresses.
2357 you will have to do that manually.
2358 For example, older versions allowed you to use
2360 0 bruce@broadcast.sony.com
2362 This version requires that you use:
2364 3,0 bruce@broadcast.sony.com
2368 some other syntaxes are available in test mode:
2373 to have the indicated
2375 This is useful when debugging rules that use the
2385 dumps the contents of the indicated ruleset.
2387 is equivalent to the command-line flag.
2389 Version 8.9 introduced more features:
2392 shows a help message.
2394 display the known mailers.
2396 print the value of macro m.
2398 print the contents of class c.
2400 returns the MX records for `host'.
2402 parse address, returning the value of
2404 and the parsed address.
2405 .ip /try\ mailer\ addr
2406 rewrite address into the form it will have when
2407 presented to the indicated mailer.
2408 .ip /tryflags\ flags
2409 set flags used by parsing. The flags can be `H' for
2410 Header or `E' for Envelope, and `S' for Sender or `R'
2411 for Recipient. These can be combined, `HR' sets
2412 flags for header recipients.
2413 .ip /canon\ hostname
2414 try to canonify hostname.
2415 .ip /map\ mapname\ key
2416 look up `key' in the indicated `mapname'.
2418 quit address test mode.
2420 .sh 2 "Persistent Host Status Information"
2423 .b HostStatusDirectory
2425 information about the status of hosts is maintained on disk
2426 and can thus be shared between different instantiations of
2428 The status of the last connection with each remote host
2429 may be viewed with the command:
2433 This information may be flushed with the command:
2437 Flushing the information prevents new
2439 processes from loading it,
2440 but does not prevent existing processes from using the status information
2441 that they already have.
2444 There are a number of configuration parameters
2445 you may want to change,
2446 depending on the requirements of your site.
2447 Most of these are set
2448 using an option in the configuration file.
2451 .q "O Timeout.queuereturn=5d"
2453 .q Timeout.queuereturn
2458 Most of these options have appropriate defaults for most sites.
2460 sites having very high mail loads may find they need to tune them
2461 as appropriate for their mail load.
2463 sites experiencing a large number of small messages,
2464 many of which are delivered to many recipients,
2465 may find that they need to adjust the parameters
2466 dealing with queue priorities.
2471 had single character option names.
2473 options have long (multi-character names).
2474 Although old short names are still accepted,
2475 most new options do not have short equivalents.
2477 This section only describes the options you are most likely
2485 All time intervals are set
2486 using a scaled syntax.
2489 represents ten minutes, whereas
2491 represents two and a half hours.
2492 The full set of scales is:
2501 .sh 3 "Queue interval"
2505 flag specifies how often a sub-daemon will run the queue.
2506 This is typically set to between fifteen minutes and one hour.
2507 If not set, or set to zero,
2508 the queue will not be run automatically.
2509 RFC 1123 section 5.3.1.1 recommends that this be at least 30 minutes.
2510 Should you need to terminate the queue jobs currently active then a SIGTERM
2511 to the parent of the process (or processes) will cleanly stop the jobs.
2512 .sh 3 "Read timeouts"
2514 Timeouts all have option names
2515 .q Timeout.\fIsuboption\fP .
2516 Most of these control SMTP operations.
2519 their default values, and the minimum values
2520 allowed by RFC 2821 section 4.5.3.2 (or RFC 1123 section 5.3.2) are:
2523 The time to wait for an SMTP connection to open
2528 If zero, uses the kernel default.
2529 In no case can this option extend the timeout
2530 longer than the kernel provides, but it can shorten it.
2531 This is to get around kernels that provide an absurdly long connection timeout
2532 (90 minutes in one case).
2536 except it applies only to the initial attempt to connect to a host
2539 The concept is that this should be very short (a few seconds);
2540 hosts that are well connected and responsive will thus be serviced immediately.
2541 Hosts that are slow will not hold up other deliveries in the initial
2545 The overall timeout waiting for all connection for a single delivery
2547 If 0, no overall limit is applied.
2548 This can be used to restrict the total amount of time trying to connect to
2549 a long list of host that could accept an e-mail for the recipient.
2550 This timeout does not apply to
2552 i.e., if the time is exhausted, the
2556 The wait for the initial 220 greeting message
2559 The wait for a reply from a HELO or EHLO command
2561 This may require a host name lookup, so
2562 five minutes is probably a reasonable minimum.
2564 The wait for a reply from a MAIL command
2567 The wait for a reply from a RCPT command
2570 because it could be pointing at a list
2571 that takes a long time to expand
2574 The wait for a reply from a DATA command
2576 .ip datablock\(dg\(dd
2577 The wait for reading a data block
2578 (that is, the body of the message).
2580 This should be long because it also applies to programs
2583 which have no guarantee of promptness.
2585 The wait for a reply from the dot terminating a message.
2587 If this is shorter than the time actually needed
2588 for the receiver to deliver the message,
2589 duplicates will be generated.
2590 This is discussed in RFC 1047.
2592 The wait for a reply from a RSET command
2595 The wait for a reply from a QUIT command
2598 The wait for a reply from miscellaneous (but short) commands
2599 such as NOOP (no-operation) and VERB (go into verbose mode).
2603 the time to wait for another command.
2606 The timeout waiting for a reply to an IDENT query
2607 [5s\**, unspecified].
2609 \**On some systems the default is zero to turn the protocol off entirely.
2612 The wait for a reply to an LMTP LHLO command
2615 The timeout for a reply in an SMTP AUTH dialogue
2618 The timeout for a reply to an SMTP STARTTLS command and the TLS handshake
2621 The timeout for opening .forward and :include: files [60s, none].
2623 The timeout for a complete control socket transaction to complete [2m, none].
2625 How long status information about a host
2627 will be cached before it is considered stale
2629 .ip resolver.retrans\(dd
2631 retransmission time interval
2635 .i Timeout.resolver.retrans.first
2637 .i Timeout.resolver.retrans.normal .
2638 .ip resolver.retrans.first\(dd
2640 retransmission time interval
2642 for the first attempt to
2645 .ip resolver.retrans.normal\(dd
2647 retransmission time interval
2649 for all resolver lookups
2650 except the first delivery attempt
2652 .ip resolver.retry\(dd
2654 to retransmit a resolver query.
2656 .i Timeout.resolver.retry.first
2658 .i Timeout.resolver.retry.normal
2660 .ip resolver.retry.first\(dd
2662 to retransmit a resolver query
2663 for the first attempt
2664 to deliver a message
2666 .ip resolver.retry.normal\(dd
2668 to retransmit a resolver query
2669 for all resolver lookups
2670 except the first delivery attempt
2673 For compatibility with old configuration files,
2677 all the timeouts marked with
2679 (\(dg) are set to the indicated value.
2680 All but those marked with
2682 (\(dd) apply to client SMTP.
2684 For example, the lines:
2686 O Timeout.command=25m
2687 O Timeout.datablock=3h
2689 sets the server SMTP command timeout to 25 minutes
2690 and the input data block timeout to three hours.
2691 .sh 3 "Message timeouts"
2693 After sitting in the queue for a few days,
2694 an undeliverable message will time out.
2695 This is to insure that at least the sender is aware
2696 of the inability to send a message.
2697 The timeout is typically set to five days.
2698 It is sometimes considered convenient to also send a warning message
2699 if the message is in the queue longer than a few hours
2700 (assuming you normally have good connectivity;
2701 if your messages normally took several hours to send
2702 you wouldn't want to do this because it wouldn't be an unusual event).
2703 These timeouts are set using the
2704 .b Timeout.queuereturn
2706 .b Timeout.queuewarn
2707 options in the configuration file
2708 (previously both were set using the
2712 If the message is submitted using the
2716 warning messages will only be sent if
2719 The queuereturn and queuewarn timeouts
2720 can be further qualified with a tag based on the Precedence: field
2724 (indicating a positive non-zero precedence),
2726 (indicating a zero precedence), or
2728 (indicating negative precedences).
2729 For example, setting
2730 .q Timeout.queuewarn.urgent=1h
2731 sets the warning timeout for urgent messages only
2733 The default if no precedence is indicated
2734 is to set the timeout for all precedences.
2735 If the message has a normal (default) precedence
2736 and it is a delivery status notification (DSN),
2737 .b Timeout.queuereturn.dsn
2739 .b Timeout.queuewarn.dsn
2740 can be used to give an alternative warn and return time
2742 The value "now" can be used for
2743 -O Timeout.queuereturn
2744 to return entries immediately during a queue run,
2745 e.g., to bounce messages independent of their time in the queue.
2747 Since these options are global,
2748 and since you cannot know
2750 how long another host outside your domain will be down,
2751 a five day timeout is recommended.
2752 This allows a recipient to fix the problem even if it occurs
2753 at the beginning of a long weekend.
2754 RFC 1123 section 5.3.1.1 says that this parameter
2755 should be ``at least 4\-5 days''.
2758 .b Timeout.queuewarn
2759 value can be piggybacked on the
2761 option by indicating a time after which
2762 a warning message should be sent;
2763 the two timeouts are separated by a slash.
2764 For example, the line
2768 causes email to fail after five days,
2769 but a warning message will be sent after four hours.
2770 This should be large enough that the message will have been tried
2772 .sh 2 "Forking During Queue Runs"
2780 will fork before each individual message
2781 while running the queue.
2782 This option was used with earlier releases to prevent
2784 from consuming large amounts of memory.
2785 It should no longer be necessary with
2792 will keep track of hosts that are down during a queue run,
2793 which can improve performance dramatically.
2799 cannot use connection caching.
2800 .sh 2 "Queue Priorities"
2802 Every message is assigned a priority when it is first instantiated,
2803 consisting of the message size (in bytes)
2804 offset by the message class
2805 (which is determined from the Precedence: header)
2807 .q "work class factor"
2808 and the number of recipients times the
2809 .q "work recipient factor."
2810 The priority is used to order the queue.
2811 Higher numbers for the priority mean that the message will be processed later
2812 when running the queue.
2814 The message size is included so that large messages are penalized
2815 relative to small messages.
2816 The message class allows users to send
2818 messages by including a
2820 field in their message;
2821 the value of this field is looked up in the
2823 lines of the configuration file.
2824 Since the number of recipients affects the amount of load a message presents
2826 this is also included into the priority.
2828 The recipient and class factors
2829 can be set in the configuration file using the
2837 options respectively.
2838 They default to 30000 (for the recipient factor)
2840 (for the class factor).
2841 The initial priority is:
2843 pri = msgsize - (class times bold ClassFactor) + (nrcpt times bold RecipientFactor)
2845 (Remember, higher values for this parameter actually mean
2846 that the job will be treated with lower priority.)
2848 The priority of a job can also be adjusted each time it is processed
2849 (that is, each time an attempt is made to deliver it)
2851 .q "work time factor,"
2857 This is added to the priority,
2858 so it normally decreases the precedence of the job,
2859 on the grounds that jobs that have failed many times
2860 will tend to fail again in the future.
2863 option defaults to 90000.
2864 .sh 2 "Load Limiting"
2867 can be asked to queue (but not deliver) mail
2868 if the system load average gets too high using the
2873 When the load average exceeds the value of the
2875 option, the delivery mode is set to
2881 option divided by the difference in the current load average and the
2884 is less than the priority of the message \(em
2885 that is, the message is queued iff:
2887 pri > { bold QueueFactor } over { LA - { bold QueueLA } + 1 }
2891 option defaults to 600000,
2892 so each point of load average is worth 600000 priority points
2893 (as described above).
2895 For drastic cases, the
2899 option defines a load average at which
2901 will refuse to accept network connections.
2902 Locally generated mail, i.e., mail which is not submitted via SMTP
2903 (including incoming UUCP mail),
2905 Notice that the MSP submits mail to the MTA via SMTP, and hence
2906 mail will be queued in the client queue in such a case.
2907 Therefore it is necessary to run the client mail queue periodically.
2908 .sh 2 "Resource Limits"
2911 has several parameters to control resource usage.
2912 Besides those mentionted in the previous section, there are at least
2913 .b MaxDaemonChildren ,
2914 .b ConnectionRateThrottle ,
2915 .b MaxQueueChildren ,
2917 .b MaxRunnersPerQueue .
2918 The latter two limit the number of
2920 processes that operate on the queue.
2921 These are discussed in the section
2922 ``Queue Group Declaration''.
2923 The former two can be used to limit the number of incoming connections.
2924 Their appropriate values depend on the host operating system and
2925 the hardware, e.g., amount of memory.
2926 In many situations it might be useful to set limits to prevent
2929 processes, however, these limits can be abused to mount a
2930 denial of service attack.
2932 .b MaxDaemonChildren=10
2933 then an attacker needs to open only 10 SMTP sessions to the server,
2934 leave them idle for most of the time,
2935 and no more connections will be accepted.
2936 If this option is set then the timeouts used in a SMTP session
2937 should be lowered from their default values to
2938 their minimum values as specified in RFC 2821 and listed in
2942 .sh 2 "Measures against Denial of Service Attacks"
2945 has some built-in measures against simple denial of service (DoS) attacks.
2946 The SMTP server by default slows down if too many bad commands are
2947 issued or if some commands are repeated too often within a session.
2948 Details can be found in the source file
2949 .b sendmail/srvrsmtp.c
2950 by looking for the macro definitions of
2952 .b MAXNOOPCOMMANDS ,
2953 .b MAXHELOCOMMANDS ,
2954 .b MAXVRFYCOMMANDS ,
2956 .b MAXETRNCOMMANDS .
2957 If an SMTP command is issued more often than the corresponding
2959 value, then the response is delayed exponentially,
2960 starting with a sleep time of one second,
2961 up to a maximum of four minutes (as defined by
2964 .b MaxDaemonChildren
2965 is set to a value greater than zero,
2966 then this could make a DoS attack even worse since it
2967 keeps a connection open longer than necessary.
2968 Therefore a connection is terminated with a 421 SMTP reply code
2969 if the number of commands exceeds the limit by a factor of two and
2971 is set to a value greater than zero (the default is 25).
2972 .sh 2 "Delivery Mode"
2974 There are a number of delivery modes that
2981 configuration option.
2983 specify how quickly mail will be delivered.
2987 i deliver interactively (synchronously)
2988 b deliver in background (asynchronously)
2989 q queue only (don't deliver)
2990 d defer delivery attempts (don't deliver)
2992 There are tradeoffs.
2995 gives the sender the quickest feedback,
2996 but may slow down some mailers and
2997 is hardly ever necessary.
3000 delivers promptly but
3001 can cause large numbers of processes
3002 if you have a mailer that takes a long time to deliver a message.
3005 minimizes the load on your machine,
3006 but means that delivery may be delayed for up to the queue interval.
3009 is identical to mode
3011 except that it also prevents lookups in maps including the
3013 flag from working during the initial queue phase;
3014 it is intended for ``dial on demand'' sites where DNS lookups
3015 might cost real money.
3016 Some simple error messages
3017 (e.g., host unknown during the SMTP protocol)
3018 will be delayed using this mode.
3021 is the usual default.
3030 (deliver in background)
3032 will not expand aliases and follow .forward files
3033 upon initial receipt of the mail.
3034 This speeds up the response to RCPT commands.
3037 should not be used by the SMTP server.
3040 The level of logging can be set for
3042 The default using a standard configuration table is level 9.
3043 The levels are as follows:
3048 Serious system failures and potential security problems.
3050 Lost communications (network problems) and protocol failures.
3052 Other serious failures, malformed addresses, transient forward/include
3053 errors, connection timeouts.
3055 Minor failures, out of date alias databases, connection rejections
3056 via check_ rulesets.
3058 Message collection statistics.
3060 Creation of error messages,
3061 VRFY and EXPN commands.
3063 Delivery failures (host or user unknown, etc.).
3065 Successful deliveries and alias database rebuilds.
3067 Messages being deferred
3068 (due to a host being down, etc.).
3070 Database expansion (alias, forward, and userdb lookups)
3071 and authentication information.
3073 NIS errors and end of job processing.
3075 Logs all SMTP connections.
3077 Log bad user shells, files with improper permissions, and other
3078 questionable situations.
3080 Logs refused connections.
3082 Log all incoming and outgoing SMTP commands.
3084 Logs attempts to run locked queue files.
3085 These are not errors,
3086 but can be useful to note if your queue appears to be clogged.
3088 Lost locks (only if using lockf instead of flock).
3091 values above 64 are reserved for extremely verbose debugging output.
3092 No normal site would ever set these.
3095 The modes used for files depend on what functionality you want
3096 and the level of security you require.
3099 does careful checking of the modes
3100 of files and directories
3101 to avoid accidental compromise;
3102 if you want to make it possible to have group-writable support files
3103 you may need to use the
3104 .b DontBlameSendmail
3105 option to turn off some of these checks.
3106 .sh 3 "To suid or not to suid?"
3109 is no longer installed
3110 set-user-ID to root.
3112 explains how to configure and install
3114 without set-user-ID to root but set-group-ID
3115 which is the default configuration starting with 8.12.
3117 The daemon usually runs as root, unless other measures are taken.
3123 it checks to see if the userid is zero (root);
3125 it resets the userid and groupid to a default
3128 equate in the mailer line;
3129 if that is not set, the
3132 This can be overridden
3136 for mailers that are trusted
3137 and must be called as root.
3139 this will cause mail processing
3144 rather than to the user sending the mail.
3146 A middle ground is to set the
3151 to become the indicated user as soon as it has done the startup
3152 that requires root privileges
3153 (primarily, opening the
3160 .i /var/spool/mqueue )
3161 should be owned by that user,
3162 and all files and databases
3168 and external databases)
3169 must be readable by that user.
3170 Also, since sendmail will not be able to change its uid,
3171 delivery to programs or files will be marked as unsafe,
3172 e.g., undeliverable,
3176 and :include: files.
3177 Administrators can override this by setting the
3178 .b DontBlameSendmail
3179 option to the setting
3180 .b NonRootSafeAddr .
3182 is probably best suited for firewall configurations
3183 that don't have regular user logins.
3184 If the option is used on a system which performs local delivery,
3185 then the local delivery agent must have the proper permissions
3186 (i.e., usually set-user-ID root)
3187 since it will be invoked by the
3190 .sh 3 "Turning off security checks"
3193 is very particular about the modes of files that it reads or writes.
3194 For example, by default it will refuse to read most files
3195 that are group writable
3196 on the grounds that they might have been tampered with
3197 by someone other than the owner;
3198 it will even refuse to read files in group writable directories.
3199 Also, sendmail will refuse to create a new aliases database in an
3200 unsafe directory. You can get around this by manually creating the
3201 database file as a trusted user ahead of time and then rebuilding the
3202 aliases database with
3207 sure that your configuration is safe and you want
3209 to avoid these security checks,
3210 you can turn off certain checks using the
3211 .b DontBlameSendmail
3213 This option takes one or more names that disable checks.
3214 In the descriptions that follow,
3215 .q "unsafe directory"
3216 means a directory that is writable by anyone other than the owner.
3220 No special handling.
3224 system call is restricted to root.
3225 Since some versions of UNIX permit regular users
3226 to give away their files to other users on some filesystems,
3228 often cannot assume that a given file was created by the owner,
3229 particularly when it is in a writable directory.
3230 You can set this flag if you know that file giveaway is restricted
3232 .ip ClassFileInUnsafeDirPath
3233 When reading class files (using the
3235 line in the configuration file),
3236 allow files that are in unsafe directories.
3237 .ip DontWarnForwardFileInUnsafeDirPath
3239 unsafe directory path warnings
3240 for non-existent forward files.
3241 .ip ErrorHeaderInUnsafeDirPath
3242 Allow the file named in the
3244 option to be in an unsafe directory.
3245 .ip FileDeliveryToHardLink
3246 Allow delivery to files that are hard links.
3247 .ip FileDeliveryToSymLink
3248 Allow delivery to files that are symbolic links.
3249 .ip ForwardFileInGroupWritableDirPath
3252 files in group writable directories.
3253 .ip ForwardFileInUnsafeDirPath
3256 files in unsafe directories.
3257 .ip ForwardFileInUnsafeDirPathSafe
3260 file that is in an unsafe directory to include references
3261 to program and files.
3262 .ip GroupReadableKeyFile
3263 Accept a group-readable key file for STARTTLS.
3264 .ip GroupReadableSASLDBFile
3265 Accept a group-readable Cyrus SASL password file.
3266 .ip GroupWritableAliasFile
3267 Allow group-writable alias files.
3268 .ip GroupWritableDirPathSafe
3269 Change the definition of
3270 .q "unsafe directory"
3271 to consider group-writable directories to be safe.
3272 World-writable directories are always unsafe.
3273 .ip GroupWritableForwardFile
3274 Allow group writable
3277 .ip GroupWritableForwardFileSafe
3278 Accept group-writable
3280 files as safe for program and file delivery.
3281 .ip GroupWritableIncludeFile
3285 .ip GroupWritableIncludeFileSafe
3286 Accept group-writable
3288 files as safe for program and file delivery.
3289 .ip GroupWritableSASLDBFile
3290 Accept a group-writable Cyrus SASL password file.
3291 .ip HelpFileInUnsafeDirPath
3292 Allow the file named in the
3294 option to be in an unsafe directory.
3295 .ip IncludeFileInGroupWritableDirPath
3298 files in group writable directories.
3299 .ip IncludeFileInUnsafeDirPath
3302 files in unsafe directories.
3303 .ip IncludeFileInUnsafeDirPathSafe
3306 file that is in an unsafe directory to include references
3307 to program and files.
3308 .ip InsufficientEntropy
3309 Try to use STARTTLS even if the PRNG for OpenSSL is not properly seeded
3310 despite the security problems.
3311 .ip LinkedAliasFileInWritableDir
3312 Allow an alias file that is a link in a writable directory.
3313 .ip LinkedClassFileInWritableDir
3314 Allow class files that are links in writable directories.
3315 .ip LinkedForwardFileInWritableDir
3318 files that are links in writable directories.
3319 .ip LinkedIncludeFileInWritableDir
3322 files that are links in writable directories.
3323 .ip LinkedMapInWritableDir
3324 Allow map files that are links in writable directories.
3325 This includes alias database files.
3326 .ip LinkedServiceSwitchFileInWritableDir
3327 Allow the service switch file to be a link
3328 even if the directory is writable.
3329 .ip MapInUnsafeDirPath
3336 in unsafe directories.
3337 This includes alias database files.
3339 Do not mark file and program deliveries as unsafe
3340 if sendmail is not running with root privileges.
3341 .ip RunProgramInUnsafeDirPath
3342 Run programs that are in writable directories without logging a warning.
3343 .ip RunWritableProgram
3344 Run programs that are group- or world-writable without logging a warning.
3346 Allow group or world writable directories
3347 if the sticky bit is set on the directory.
3348 Do not set this on systems which do not honor
3349 the sticky bit on directories.
3350 .ip WorldWritableAliasFile
3351 Accept world-writable alias files.
3352 .ip WorldWritableForwardfile
3353 Allow world writable
3356 .ip WorldWritableIncludefile
3360 .ip WriteMapToHardLink
3361 Allow writes to maps that are hard links.
3362 .ip WriteMapToSymLink
3363 Allow writes to maps that are symbolic links.
3364 .ip WriteStatsToHardLink
3365 Allow the status file to be a hard link.
3366 .ip WriteStatsToSymLink
3367 Allow the status file to be a symbolic link.
3368 .sh 2 "Connection Caching"
3370 When processing the queue,
3372 will try to keep the last few open connections open
3373 to avoid startup and shutdown costs.
3374 This only applies to IPC and LPC connections.
3376 When trying to open a connection
3377 the cache is first searched.
3378 If an open connection is found, it is probed to see if it is still active
3382 It is not an error if this fails;
3383 instead, the connection is closed and reopened.
3385 Two parameters control the connection cache.
3387 .b ConnectionCacheSize
3390 option defines the number of simultaneous open connections
3391 that will be permitted.
3392 If it is set to zero,
3393 connections will be closed as quickly as possible.
3395 This should be set as appropriate for your system size;
3396 it will limit the amount of system resources that
3398 will use during queue runs.
3399 Never set this higher than 4.
3402 .b ConnectionCacheTimeout
3405 option specifies the maximum time that any cached connection
3406 will be permitted to idle.
3407 When the idle time exceeds this value
3408 the connection is closed.
3409 This number should be small
3411 to prevent you from grabbing too many resources
3413 The default is five minutes.
3414 .sh 2 "Name Server Access"
3416 Control of host address lookups is set by the
3418 service entry in your service switch file.
3419 If you are on a system that has built-in service switch support
3420 (e.g., Ultrix, Solaris, or DEC OSF/1)
3421 then your system is probably configured properly already.
3424 will consult the file
3425 .b /etc/mail/service.switch ,
3426 which should be created.
3428 only uses two entries:
3432 although system routines may use other services
3435 service for user name lookups by
3438 However, some systems (such as SunOS 4.X)
3440 regardless of the setting of the service switch entry.
3441 In particular, the system routine
3442 .i gethostbyname (3)
3443 is used to look up host names,
3444 and many vendor versions try some combination of DNS, NIS,
3445 and file lookup in /etc/hosts
3446 without consulting a service switch.
3448 makes no attempt to work around this problem,
3449 and the DNS lookup will be done anyway.
3450 If you do not have a nameserver configured at all,
3451 such as at a UUCP-only site,
3454 .q "connection refused"
3455 message when it tries to connect to the name server.
3458 switch entry has the service
3460 listed somewhere in the list,
3462 will interpret this to mean a temporary failure
3463 and will queue the mail for later processing;
3464 otherwise, it ignores the name server data.
3466 The same technique is used to decide whether to do MX lookups.
3467 If you want MX support, you
3471 listed as a service in the
3479 option allows you to tweak name server options.
3480 The command line takes a series of flags as documented in
3485 Each can be preceded by an optional `+' or `\(mi'.
3486 For example, the line
3488 O ResolverOptions=+AAONLY \(miDNSRCH
3490 turns on the AAONLY (accept authoritative answers only)
3491 and turns off the DNSRCH (search the domain path) options.
3492 Most resolver libraries default DNSRCH, DEFNAMES, and RECURSE
3493 flags on and all others off.
3494 If NETINET6 is enabled, most libraries default to USE_INET6 as well.
3495 You can also include
3497 to specify that there is a wildcard MX record matching your domain;
3498 this turns off MX matching when canonifying names,
3499 which can lead to inappropriate canonifications.
3501 .q WorkAroundBrokenAAAA
3502 when faced with a broken nameserver that returns SERVFAIL
3503 (a temporary failure)
3504 on T_AAAA (IPv6) lookups
3505 during hostname canonification.
3506 Notice: it might be necessary to apply the same (or similar) options to
3510 Version level 1 configurations (see the section about
3511 ``Configuration Version Level'')
3512 turn DNSRCH and DEFNAMES off when doing delivery lookups,
3513 but leave them on everywhere else.
3516 ignores them when doing canonification lookups
3517 (that is, when using $[ ... $]),
3518 and always does the search.
3519 If you don't want to do automatic name extension,
3520 don't call $[ ... $].
3522 The search rules for $[ ... $] are somewhat different than usual.
3523 If the name being looked up
3524 has at least one dot, it always tries the unmodified name first.
3525 If that fails, it tries the reduced search path,
3526 and lastly tries the unmodified name
3527 (but only for names without a dot,
3528 since names with a dot have already been tried).
3529 This allows names such as
3531 to match the site in Czechoslovakia
3532 rather than the site in your local Computer Science department.
3533 It also prefers A and CNAME records over MX records \*-
3534 that is, if it finds an MX record it makes note of it,
3536 This way, if you have a wildcard MX record matching your domain,
3537 it will not assume that all names match.
3539 To completely turn off all name server access
3540 on systems without service switch support
3542 you will have to recompile with
3544 and remove \-lresolv from the list of libraries to be searched
3546 .sh 2 "Moving the Per-User Forward Files"
3548 Some sites mount each user's home directory
3549 from a local disk on their workstation,
3550 so that local access is fast.
3551 However, the result is that .forward file lookups
3552 from a central mail server are slow.
3554 mail can even be delivered on machines inappropriately
3555 because of a file server being down.
3556 The performance can be especially bad if you run the automounter.
3562 option allows you to set a path of forward files.
3563 For example, the config file line
3565 O ForwardPath=/var/forward/$u:$z/.forward.$w
3567 would first look for a file with the same name as the user's login
3569 if that is not found (or is inaccessible)
3573 in the user's home directory is searched.
3574 A truly perverse site could also search by sender
3575 by using $r, $s, or $f.
3577 If you create a directory such as /var/forward,
3578 it should be mode 1777
3579 (that is, the sticky bit should be set).
3580 Users should create the files mode 0644.
3581 Note that you must use the
3582 ForwardFileInUnsafeDirPath and
3583 ForwardFileInUnsafeDirPathSafe
3585 .b DontBlameSendmail
3586 option to allow forward files in a world writable directory.
3587 This might also be used as a denial of service attack
3588 (users could create forward files for other users);
3589 a better approach might be to create
3592 and create empty files for each user,
3595 If you do this, you don't have to set the DontBlameSendmail options
3599 On systems that have one of the system calls in the
3606 you can specify a minimum number of free blocks on the queue filesystem
3612 If there are fewer than the indicated number of blocks free
3613 on the filesystem on which the queue is mounted
3614 the SMTP server will reject mail
3617 This invites the SMTP client to try again later.
3619 Beware of setting this option too high;
3620 it can cause rejection of email
3621 when that mail would be processed without difficulty.
3622 .sh 2 "Maximum Message Size"
3624 To avoid overflowing your system with a large message,
3627 option can be set to set an absolute limit
3628 on the size of any one message.
3629 This will be advertised in the ESMTP dialogue
3630 and checked during message collection.
3631 .sh 2 "Privacy Flags"
3637 option allows you to set certain
3640 Actually, many of them don't give you any extra privacy,
3641 rather just insisting that client SMTP servers
3642 use the HELO command
3643 before using certain commands
3644 or adding extra headers to indicate possible spoof attempts.
3646 The option takes a series of flag names;
3647 the final privacy is the inclusive or of those flags.
3650 O PrivacyOptions=needmailhelo, noexpn
3652 insists that the HELO or EHLO command be used before a MAIL command is accepted
3653 and disables the EXPN command.
3655 The flags are detailed in section
3658 .sh 2 "Send to Me Too"
3660 Beginning with version 8.10,
3662 includes by default the (envelope) sender in any list expansions.
3665 sends to a list that contains
3667 as one of the members he will get a copy of the message.
3672 (in the configuration file or via the command line),
3673 this behavior is changed, i.e.,
3674 the (envelope) sender is excluded in list expansions.
3675 .sh 1 "THE WHOLE SCOOP ON THE CONFIGURATION FILE"
3677 This section describes the configuration file
3680 There is one point that should be made clear immediately:
3681 the syntax of the configuration file
3682 is designed to be reasonably easy to parse,
3683 since this is done every time
3686 rather than easy for a human to read or write.
3687 The configuration file should be generated via the method described in
3689 it should not be edited directly unless someone is familiar
3690 with the internals of the syntax described here and it is
3691 not possible to achieve the desired result via the default method.
3693 The configuration file is organized as a series of lines,
3694 each of which begins with a single character
3695 defining the semantics for the rest of the line.
3696 Lines beginning with a space or a tab
3697 are continuation lines
3698 (although the semantics are not well defined in many places).
3699 Blank lines and lines beginning with a sharp symbol
3702 .sh 2 "R and S \*- Rewriting Rules"
3704 The core of address parsing
3705 are the rewriting rules.
3706 These are an ordered production system.
3708 scans through the set of rewriting rules
3709 looking for a match on the left hand side
3712 When a rule matches,
3713 the address is replaced by the right hand side
3717 There are several sets of rewriting rules.
3718 Some of the rewriting sets are used internally
3719 and must have specific semantics.
3720 Other rewriting sets
3721 do not have specifically assigned semantics,
3722 and may be referenced by the mailer definitions
3723 or by other rewriting sets.
3725 The syntax of these two commands are:
3730 Sets the current ruleset being collected to
3732 If you begin a ruleset more than once
3733 it appends to the old definition.
3741 fields must be separated
3742 by at least one tab character;
3743 there may be embedded spaces
3747 is a pattern that is applied to the input.
3749 the input is rewritten to the
3755 Macro expansions of the form
3758 are performed when the configuration file is read.
3761 can be included using
3763 Expansions of the form
3766 are performed at run time using a somewhat less general algorithm.
3767 This is intended only for referencing internally defined macros
3770 that are changed at runtime.
3771 .sh 3 "The left hand side"
3773 The left hand side of rewriting rules contains a pattern.
3774 Normal words are simply matched directly.
3775 Metasyntax is introduced using a dollar sign.
3776 The metasymbols are:
3778 .ta \w'\fB$=\fP\fIx\fP 'u
3779 \fB$*\fP Match zero or more tokens
3780 \fB$+\fP Match one or more tokens
3781 \fB$\-\fP Match exactly one token
3782 \fB$=\fP\fIx\fP Match any phrase in class \fIx\fP
3783 \fB$~\fP\fIx\fP Match any word not in class \fIx\fP
3785 If any of these match,
3786 they are assigned to the symbol
3789 for replacement on the right hand side,
3792 is the index in the LHS.
3798 is applied to the input:
3802 the rule will match, and the values passed to the RHS will be:
3809 Additionally, the LHS can include
3811 to match zero tokens.
3817 on the RHS, and is normally only used when it stands alone
3818 in order to match the null input.
3819 .sh 3 "The right hand side"
3821 When the left hand side of a rewriting rule matches,
3822 the input is deleted and replaced by the right hand side.
3823 Tokens are copied directly from the RHS
3824 unless they begin with a dollar sign.
3827 .ta \w'$#mailer\0\0\0'u
3828 \fB$\fP\fIn\fP Substitute indefinite token \fIn\fP from LHS
3829 \fB$[\fP\fIname\fP\fB$]\fP Canonicalize \fIname\fP
3830 \fB$(\fP\fImap key\fP \fB$@\fP\fIarguments\fP \fB$:\fP\fIdefault\fP \fB$)\fP
3831 Generalized keyed mapping function
3832 \fB$>\fP\fIn\fP \*(lqCall\*(rq ruleset \fIn\fP
3833 \fB$#\fP\fImailer\fP Resolve to \fImailer\fP
3834 \fB$@\fP\fIhost\fP Specify \fIhost\fP
3835 \fB$:\fP\fIuser\fP Specify \fIuser\fP
3841 syntax substitutes the corresponding value from a
3849 It may be used anywhere.
3851 A host name enclosed between
3855 is looked up in the host database(s)
3856 and replaced by the canonical name\**.
3859 completely equivalent
3860 to $(host \fIhostname\fP$).
3863 default can be used.
3868 .q ftp.CS.Berkeley.EDU
3870 .q $[[128.32.130.2]$]
3872 .q vangogh.CS.Berkeley.EDU.
3874 recognizes its numeric IP address
3875 without calling the name server
3876 and replaces it with its canonical name.
3882 syntax is a more general form of lookup;
3883 it uses a named map instead of an implicit map.
3884 If no lookup is found, the indicated
3887 if no default is specified and no lookup matches,
3888 the value is left unchanged.
3891 are passed to the map for possible use.
3897 causes the remainder of the line to be substituted as usual
3898 and then passed as the argument to ruleset
3900 The final value of ruleset
3903 the substitution for this rule.
3906 syntax expands everything after the ruleset name
3907 to the end of the replacement string
3908 and then passes that as the initial input to the ruleset.
3909 Recursive calls are allowed.
3914 expands $1, passes that to ruleset 3, and then passes the result
3915 of ruleset 3 to ruleset 0.
3921 be used in ruleset zero,
3922 a subroutine of ruleset zero,
3923 or rulesets that return decisions (e.g., check_rcpt).
3924 It causes evaluation of the ruleset to terminate immediately,
3927 that the address has completely resolved.
3928 The complete syntax for ruleset 0 is:
3930 \fB$#\fP\fImailer\fP \fB$@\fP\fIhost\fP \fB$:\fP\fIuser\fP
3933 {mailer, host, user}
3934 3-tuple necessary to direct the mailer.
3935 Note: the third element (
3937 ) is often also called
3940 If the mailer is local
3941 the host part may be omitted\**.
3943 \**You may want to use it for special
3946 For example, in the address
3947 .q jgm+foo@CMU.EDU ;
3950 part is not part of the user name,
3951 and is passed to the local mailer for local use.
3955 must be a single word,
3963 is the built-in IPC mailer,
3966 may be a colon-separated list of hosts
3967 that are searched in order for the first working address
3968 (exactly like MX records).
3971 is later rewritten by the mailer-specific envelope rewriting set
3975 As a special case, if the mailer specified has the
3978 and the first character of the
3984 is stripped off, and a flag is set in the address descriptor
3985 that causes sendmail to not do ruleset 5 processing.
3987 Normally, a rule that matches is retried,
3989 the rule loops until it fails.
3990 A RHS may also be preceded by a
3994 to change this behavior.
3997 prefix causes the ruleset to return with the remainder of the RHS
4001 prefix causes the rule to terminate immediately,
4002 but the ruleset to continue;
4003 this can be used to avoid continued application of a rule.
4004 The prefix is stripped before continuing.
4010 prefixes may precede a
4019 passes that to ruleset seven,
4023 is necessary to avoid an infinite loop.
4025 Substitution occurs in the order described,
4027 parameters from the LHS are substituted,
4028 hostnames are canonicalized,
4037 .sh 3 "Semantics of rewriting rule sets"
4039 There are six rewriting sets
4040 that have specific semantics.
4041 Five of these are related as depicted by figure 1.
4047 -->| 0 |-->resolved address
4050 / ---->| 1 |-->| S |--
4051 +---+ / +---+ / +---+ +---+ \e +---+
4052 addr-->| 3 |-->| D |-- --->| 4 |-->msg
4053 +---+ +---+ \e +---+ +---+ / +---+
4069 box invis "addr"; arrow
4072 BoxD: box "D"; line; L1: Here
4074 C1: arrow; box "1"; arrow; box "S"; line; E1: Here
4075 move to C1 down 0.5; right
4076 C2: arrow; box "2"; arrow; box "R"; line; E2: Here
4077 ] with .w at L1 + (0.5, 0)
4078 move to C.e right 0.5
4079 L4: arrow; box "4"; arrow; box invis "msg"
4080 line from L1 to C.C1
4081 line from L1 to C.C2
4082 line from C.E1 to L4
4083 line from C.E2 to L4
4084 move to BoxD.n up 0.6; right
4085 Box0: arrow; box "0"
4086 arrow; box invis "resolved address" width 1.3
4087 line from 1/3 of the way between A1 and BoxD.w to Box0
4093 Figure 1 \*- Rewriting set semantics
4095 D \*- sender domain addition
4096 S \*- mailer-specific sender rewriting
4097 R \*- mailer-specific recipient rewriting
4103 should turn the address into
4104 .q "canonical form."
4105 This form should have the basic syntax:
4107 local-part@host-domain-spec
4112 before doing anything with any address.
4127 flag is set in the mailer definition
4128 corresponding to the
4133 is applied after ruleset three
4134 to addresses that are going to actually specify recipients.
4135 It must resolve to a
4136 .i "{mailer, host, address}"
4140 must be defined in the mailer definitions
4141 from the configuration file.
4147 for use in the argv expansion of the specified mailer.
4148 Notice: since the envelope sender address will be used if
4149 a delivery status notification must be send,
4150 i.e., is may specify a recipient,
4151 it is also run through ruleset zero.
4152 If ruleset zero returns a temporary error
4154 then delivery is deferred.
4155 This can be used to temporarily disable delivery,
4156 e.g., based on the time of the day or other varying parameters.
4157 It should not be used to quarantine e-mails.
4159 Rulesets one and two
4160 are applied to all sender and recipient addresses respectively.
4161 They are applied before any specification
4162 in the mailer definition.
4163 They must never resolve.
4165 Ruleset four is applied to all addresses
4167 It is typically used
4168 to translate internal to external form.
4171 ruleset 5 is applied to all local addresses
4172 (specifically, those that resolve to a mailer with the `F=5'
4174 that do not have aliases.
4175 This allows a last minute hook for local names.
4176 .sh 3 "Ruleset hooks"
4178 A few extra rulesets are defined as
4180 that can be defined to get special features.
4181 They are all named rulesets.
4184 forms all give accept/reject status;
4185 falling off the end or returning normally is an accept,
4188 is a reject or quarantine.
4189 Quarantining is chosen by specifying
4191 in the second part of the mailer triplet:
4193 $#error $@ quarantine $: Reason for quarantine
4195 Many of these can also resolve to the special mailer name
4197 this accepts the message as though it were successful
4198 but then discards it without delivery.
4200 this mailer cannot be chosen as a mailer in ruleset 0.
4203 rulesets have to deal with temporary failures, especially for map lookups,
4204 themselves, i.e., they should return a temporary error code
4205 or at least they should make a proper decision in those cases.
4210 ruleset is called after a connection is accepted by the daemon.
4211 It is not called when sendmail is started using the
4216 client.host.name $| client.host.address
4220 is a metacharacter separating the two parts.
4221 This ruleset can reject connections from various locations.
4222 Note that it only checks the connecting SMTP client IP address and hostname.
4223 It does not check for third party message relaying.
4226 ruleset discussed below usually does third party message relay checking.
4231 ruleset is passed the user name parameter of the
4234 It can accept or reject the address.
4239 ruleset is passed the user name parameter of the
4242 It can accept or reject the address.
4247 ruleset is called after the
4249 command, its parameter is the number of recipients.
4250 It can accept or reject the command.
4251 .sh 4 "check_compat"
4257 sender-address $| recipient-address
4261 is a metacharacter separating the addresses.
4262 It can accept or reject mail transfer between these two addresses
4269 rulesets are invoked during the SMTP mail receiption stage
4270 (i.e., in the SMTP server),
4272 is invoked during the mail delivery stage.
4279 number-of-headers $| size-of-headers
4283 is a metacharacter separating the numbers.
4284 These numbers can be used for size comparisons with the
4287 The ruleset is triggered after
4288 all of the headers have been read.
4289 It can be used to correlate information gathered
4290 from those headers using the
4293 One possible use is to check for a missing header.
4298 HMessage-Id: $>CheckMessageId
4301 # Record the presence of the header
4302 R$* $: $(storage {MessageIdCheck} $@ OK $) $1
4304 R$* $#error $: 553 Header Error
4308 R$* $: < $&{MessageIdCheck} >
4309 # Clear the macro for the next message
4310 R$* $: $(storage {MessageIdCheck} $) $1
4311 # Has a Message-Id: header
4313 # Allow missing Message-Id: from local mail
4314 R$* $: < $&{client_name} >
4317 # Otherwise, reject the mail
4318 R$* $#error $: 553 Header Error
4320 Keep in mind the Message-Id: header is not a required header and
4321 is not a guaranteed spam indicator.
4322 This ruleset is an example and
4323 should probably not be used in production.
4328 ruleset is called after the end of a message,
4329 its parameter is the message size.
4330 It can accept or reject the message.
4335 ruleset is passed the parameter of the
4338 It can accept or reject the command.
4343 ruleset is passed the user name parameter of the
4346 It can accept or reject the address.
4351 ruleset is passed the user name parameter of the
4354 It can accept or reject the command.
4359 ruleset is passed the AUTH= parameter of the
4362 It is used to determine whether this value should be
4363 trusted. In order to make this decision, the ruleset
4364 may make use of the various
4367 If the ruleset does resolve to the
4369 mailer the AUTH= parameter is not trusted and hence
4370 not passed on to the next relay.
4375 ruleset is called when sendmail acts as server, after a STARTTLS command
4376 has been issued, and from
4378 The parameter is the value of
4380 and STARTTLS or MAIL, respectively.
4381 If the ruleset does resolve to the
4383 mailer, the appropriate error code is returned to the client.
4388 ruleset is called when sendmail acts as client after a STARTTLS command
4389 (should) have been issued.
4390 The parameter is the value of
4392 If the ruleset does resolve to the
4394 mailer, the connection is aborted
4395 (treated as non-deliverable with a permanent or temporary error).
4400 ruleset is called each time before a RCPT TO command is sent.
4401 The parameter is the current recipient.
4402 If the ruleset does resolve to the
4404 mailer, the RCPT TO command is suppressed
4405 (treated as non-deliverable with a permanent or temporary error).
4406 This ruleset allows to require encryption or verification of
4407 the recipient's MTA even if the mail is somehow redirected
4409 For example, sending mail to
4411 may get redirected to a host named
4413 and hence the tls_server ruleset won't apply.
4414 By introducing per recipient restrictions such attacks
4415 (e.g., via DNS spoofing) can be made impossible.
4418 how this ruleset can be used.
4419 .sh 4 "srv_features"
4423 ruleset is called with the connecting client's host name
4424 when a client connects to sendmail.
4425 This ruleset should return
4427 followed by a list of options (single characters
4428 delimited by white space).
4429 If the return value starts with anything else it is silently ignored.
4430 Generally upper case characters turn off a feature
4431 while lower case characters turn it on.
4432 Option `S' causes the server not to offer STARTTLS,
4433 which is useful to interact with MTAs/MUAs that have broken
4434 STARTTLS implementations by simply not offering it.
4435 `V' turns off the request for a client certificate during the TLS handshake.
4436 Options `A' and `P' suppress SMTP AUTH and PIPELINING, respectively.
4437 `c' is the equivalent to AuthOptions=p, i.e.,
4438 it doesn't permit mechanisms susceptible to simple
4439 passive attack (e.g., PLAIN, LOGIN), unless a security layer is active.
4440 Option `l' requires SMTP AUTH for a connection.
4441 Options 'B', 'D', 'E', and 'X' suppress SMTP VERB, DSN, ETRN, and EXPN,
4446 a Offer AUTH (default)
4448 b Offer VERB (default)
4449 C Do not require security layer for
4450 plaintext AUTH (default)
4451 c Require security layer for plaintext AUTH
4453 d Offer DSN (default)
4455 e Offer ETRN (default)
4456 L Do not require AUTH (default)
4458 P Do not offer PIPELINING
4459 p Offer PIPELINING (default)
4460 S Do not offer STARTTLS
4461 s Offer STARTTLS (default)
4462 V Do not request a client certificate
4463 v Request a client certificate (default)
4465 x Offer EXPN (default)
4467 Note: the entries marked as ``(default)'' may require that some
4468 configuration has been made, e.g., SMTP AUTH is only available if
4469 properly configured.
4470 Moreover, many options can be changed on a global basis via other
4471 settings as explained in this document, e.g., via DaemonPortOptions.
4473 The ruleset may return `$#temp' to indicate that there is a temporary
4474 problem determining the correct features, e.g., if a map is unavailable.
4475 In that case, the SMTP server issues a temporary failure and does not
4481 ruleset is called when sendmail connects to another MTA.
4482 If the ruleset does resolve to the
4484 mailer, sendmail does not try STARTTLS even if it is offered.
4485 This is useful to interact with MTAs that have broken
4486 STARTTLS implementations by simply not using it.
4491 ruleset is called when sendmail tries to authenticate to another MTA.
4494 followed by a list of tokens that are used for SMTP AUTH.
4495 If the return value starts with anything else it is silently ignored.
4496 Each token is a tagged string of the form:
4498 (including the quotes), where
4501 T Tag which describes the item
4502 D Delimiter: ':' simple text follows
4503 '=' string is base64 encoded
4504 string Value of the item
4506 Valid values for the tag are:
4509 U user (authorization) id
4513 M list of mechanisms delimited by spaces
4515 If this ruleset is defined, the option
4517 is ignored (even if the ruleset does not return a ``useful'' result).
4522 ruleset is used to map a recipient address to a queue group name.
4523 The input for the ruleset is a recipient address as specified by the
4526 The ruleset should return
4528 followed by the name of a queue group.
4529 If the return value starts with anything else it is silently ignored.
4530 See the section about ``Queue Groups and Queue Directories''
4531 for further information.
4536 ruleset is used to specify the amount of time to pause before sending the
4537 initial SMTP 220 greeting.
4538 If any traffic is received during that pause, an SMTP 554 rejection
4539 response is given instead of the 220 greeting and all SMTP commands are
4540 rejected during that connection.
4541 This helps protect sites from open proxies and SMTP slammers.
4542 The ruleset should return
4544 followed by the number of milliseconds (thousandths of a second) to
4546 If the return value starts with anything else or is not a number,
4547 it is silently ignored.
4548 Note: this ruleset is not invoked (and hence the feature is disabled)
4549 when the smtps (SMTP over SSL) is used, i.e.,
4552 modifier is set for the daemon via
4553 .b DaemonPortOptions ,
4554 because in this case the SSL handshake is performed before
4555 the greeting is sent.
4558 Some special processing occurs
4559 if the ruleset zero resolves to an IPC mailer
4560 (that is, a mailer that has
4562 listed as the Path in the
4565 The host name passed after
4567 has MX expansion performed if not delivering via a named socket;
4568 this looks the name up in DNS to find alternate delivery sites.
4570 The host name can also be provided as a dotted quad
4571 or an IPv6 address in square brackets;
4578 [IPv6:2002:c0a8:51d2::23f4]
4580 This causes direct conversion of the numeric value
4581 to an IP host address.
4583 The host name passed in after the
4585 may also be a colon-separated list of hosts.
4586 Each is separately MX expanded and the results are concatenated
4587 to make (essentially) one long MX list.
4588 The intent here is to create
4590 MX records that are not published in DNS
4591 for private internal networks.
4593 As a final special case, the host name can be passed in
4597 [ucbvax.berkeley.edu]
4599 This form avoids the MX mapping.
4602 This is intended only for situations where you have a network firewall
4603 or other host that will do special processing for all your mail,
4604 so that your MX record points to a gateway machine;
4605 this machine could then do direct delivery to machines
4606 within your local domain.
4607 Use of this feature directly violates RFC 1123 section 5.3.5:
4608 it should not be used lightly.
4610 .sh 2 "D \*- Define Macro"
4612 Macros are named with a single character
4613 or with a word in {braces}.
4614 The names ``x'' and ``{x}'' denote the same macro
4615 for every single character ``x''.
4616 Single character names may be selected from the entire ASCII set,
4617 but user-defined macros
4618 should be selected from the set of upper case letters only.
4621 are used internally.
4622 Long names beginning with a lower case letter or a punctuation character
4623 are reserved for use by sendmail,
4624 so user-defined long macro names should begin with an upper case letter.
4626 The syntax for macro definitions is:
4633 is the name of the macro
4634 (which may be a single character
4635 or a word in braces)
4638 is the value it should have.
4639 There should be no spaces given
4640 that do not actually belong in the macro value.
4642 Macros are interpolated
4648 is the name of the macro to be interpolated.
4649 This interpolation is done when the configuration file is read,
4653 The special construct
4658 lines to get deferred interpolation.
4660 Conditionals can be specified using the syntax:
4662 $?x text1 $| text2 $.
4668 is set and non-null,
4676 clause may be omitted.
4678 The following macros are defined and/or used internally by
4680 for interpolation into argv's for mailers
4681 or for other contexts.
4682 The ones marked \(dg are information passed into sendmail\**,
4684 \**As of version 8.6,
4685 all of these macros have reasonable defaults.
4686 Previous versions required that they be defined.
4688 the ones marked \(dd are information passed both in and out of sendmail,
4689 and the unmarked macros are passed out of sendmail
4690 but are not otherwise used internally.
4694 The origination date in RFC 822 format.
4695 This is extracted from the Date: line.
4697 The current date in RFC 822 format.
4700 This is a count of the number of Received: lines
4701 plus the value of the
4705 The current date in UNIX (ctime) format.
4707 (Obsolete; use SmtpGreetingMessage option instead.)
4708 The SMTP entry message.
4709 This is printed out when SMTP starts up.
4710 The first word must be the
4712 macro as specified by RFC 821.
4714 .q "$j Sendmail $v ready at $b" .
4715 Commonly redefined to include the configuration version number, e.g.,
4716 .q "$j Sendmail $v/$Z ready at $b"
4718 The envelope sender (from) address.
4720 The sender address relative to the recipient.
4728 .q foo@host.domain ,
4729 or whatever is appropriate for the receiving mailer.
4732 This is set in ruleset 0 from the $@ field of a parsed address.
4738 The \*(lqofficial\*(rq domain name for this site.
4739 This is fully qualified if the full qualification can be found.
4742 be redefined to be the fully qualified domain name
4743 if your system is not configured so that information can find
4746 The UUCP node name (from the uname system call).
4748 (Obsolete; use UnixFromLine option instead.)
4749 The format of the UNIX from line.
4750 Unless you have changed the UNIX mailbox format,
4751 you should not change the default,
4755 The domain part of the \fIgethostname\fP return value.
4756 Under normal circumstances,
4761 The name of the daemon (for error messages).
4765 (Obsolete: use OperatorChars option instead.)
4766 The set of \*(lqoperators\*(rq in addresses.
4767 A list of characters
4768 which will be considered tokens
4769 and which will separate tokens
4775 macro, then the input
4777 would be scanned as three tokens:
4784 which is the minimum set necessary to do RFC 822 parsing;
4785 a richer set of operators is
4787 which adds support for UUCP, the %-hack, and X.400 addresses.
4789 Sendmail's process id.
4791 Default format of sender address.
4794 macro specifies how an address should appear in a message
4795 when it is defaulted.
4798 It is commonly redefined to be
4799 .q "$?x$x <$g>$|$g$."
4802 corresponding to the following two formats:
4804 Eric Allman <eric@CS.Berkeley.EDU>
4805 eric@CS.Berkeley.EDU (Eric Allman)
4808 properly quotes names that have special characters
4809 if the first form is used.
4811 Protocol used to receive the message.
4814 command line flag or by the SMTP server code.
4819 command line flag or by the SMTP server code
4820 (in which case it is set to the EHLO/HELO parameter).
4822 A numeric representation of the current time in the format YYYYMMDDHHmm
4823 (4 digit year 1900-9999, 2 digit month 01-12, 2 digit day 01-31,
4824 2 digit hours 00-23, 2 digit minutes 00-59).
4828 The version number of the
4832 The hostname of this site.
4833 This is the root name of this host (but see below for caveats).
4835 The full name of the sender.
4837 The home directory of the recipient.
4839 The validated sender address.
4841 .b ${client_resolve} .
4843 The type of the address which is currently being rewritten.
4844 This macro contains up to three characters, the first
4845 is either `e' or `h' for envelope/header address,
4846 the second is a space,
4847 and the third is either `s' or `r' for sender/recipient address.
4849 The maximum keylength (in bits) of the symmetric encryption algorithm
4850 used for a TLS connection.
4851 This may be less than the effective keylength,
4854 for ``export controlled'' algorithms.
4856 The client's authentication credentials as determined by authentication
4857 (only set if successful).
4858 The format depends on the mechanism used, it might be just `user',
4859 or `user@realm', or something similar (SMTP AUTH only).
4861 The authorization identity, i.e. the AUTH= parameter of the
4863 command if supplied.
4865 The mechanism used for SMTP authentication
4866 (only set if successful).
4868 The keylength (in bits) of the symmetric encryption algorithm
4869 used for the security layer of a SASL mechanism.
4871 The message body type
4873 as determined from the envelope.
4875 The DN (distinguished name) of the CA (certificate authority)
4876 that signed the presented certificate (the cert issuer)
4879 The MD5 hash of the presented certificate (STARTTLS only).
4881 The DN of the presented certificate (called the cert subject)
4884 The cipher suite used for the connection, e.g., EDH-DSS-DES-CBC3-SHA,
4885 EDH-RSA-DES-CBC-SHA, DES-CBC-MD5, DES-CBC3-SHA
4888 The effective keylength (in bits) of the symmetric encryption algorithm
4889 used for a TLS connection.
4891 The IP address of the SMTP client.
4892 IPv6 addresses are tagged with "IPv6:" before the address.
4893 Defined in the SMTP server only.
4894 .ip ${client_connections}
4895 The number of open connections in the SMTP server for the client IP address.
4897 The flags specified by the
4899 .b ClientPortOptions
4900 where flags are separated from each other by spaces
4901 and upper case flags are doubled.
4904 will be represented as
4906 .b ${client_flags} ,
4907 which is required for testing the flags in rulesets.
4909 The host name of the SMTP client.
4910 This may be the client's bracketed IP address
4911 in the form [ nnn.nnn.nnn.nnn ] for IPv4
4912 and [ IPv6:nnnn:...:nnnn ] for IPv6
4914 IP address is not resolvable, or if it is resolvable
4915 but the IP address of the resolved hostname
4916 doesn't match the original IP address.
4917 Defined in the SMTP server only.
4919 .b ${client_resolve} .
4921 The port number of the SMTP client.
4922 Defined in the SMTP server only.
4924 The result of the PTR lookup for the client IP address.
4925 Note: this is the same as
4928 .b ${client_resolve}
4930 Defined in the SMTP server only.
4932 The number of incoming connections for the client IP address
4933 over the time interval specified by ConnectionRateWindowSize.
4934 .ip ${client_resolve}
4935 Holds the result of the resolve call for
4937 Possible values are:
4940 OK resolved successfully
4941 FAIL permanent lookup failure
4942 FORGED forward lookup doesn't match reverse lookup
4943 TEMP temporary lookup failure
4945 Defined in the SMTP server only.
4947 performs a hostname lookup on the IP address of the connecting client.
4948 Next the IP addresses of that hostname are looked up.
4949 If the client IP address does not appear in that list,
4950 then the hostname is maybe forged.
4951 This is reflected as the value FORGED for
4952 .b ${client_resolve}
4953 and it also shows up in
4955 as "(may be forged)".
4957 The CN (common name) of the CA that signed the presented certificate
4959 Note: if the CN cannot be extracted properly it will be replaced by
4960 one of these strings based on the encountered error:
4963 BadCertificateContainsNUL CN contains a NUL character
4964 BadCertificateTooLong CN is too long
4965 BadCertificateUnknown CN could not be extracted
4967 In the last case, some other (unspecific) error occurred.
4969 The CN (common name) of the presented certificate
4973 for possible replacements.
4975 Header value as quoted string
4976 (possibly truncated to
4978 This macro is only available in header check rulesets.
4980 The IP address the daemon is listening on for connections.
4981 .ip ${daemon_family}
4983 if the daemon is accepting network connections.
4984 Possible values include
4991 The flags for the daemon as specified by the
4993 .b DaemonPortOptions
4994 whereby the flags are separated from each other by spaces,
4995 and upper case flags are doubled.
4998 will be represented as
5000 .b ${daemon_flags} ,
5001 which is required for testing the flags in rulesets.
5003 Some information about a daemon as a text string.
5005 .q SMTP+queueing@00:30:00 .
5007 The name of the daemon from
5008 .b DaemonPortOptions
5010 If this suboption is not set,
5012 where # is the daemon number,
5015 The port the daemon is accepting connection on.
5017 .b DaemonPortOptions
5018 is set, this will most likely be
5021 The current delivery mode sendmail is using.
5022 It is initially set to the value of the
5026 The envelope id parameter (ENVID=) passed to sendmail as part of the envelope.
5028 The length of the header value which is stored in
5029 ${currHeader} (before possible truncation).
5030 If this value is greater than or equal to
5032 the header has been truncated.
5034 The name of the header field for which the current header
5035 check ruleset has been called.
5036 This is useful for a default header check ruleset to get
5037 the name of the header;
5038 the macro is only available in header check rulesets.
5040 The IP address of the interface of an incoming connection
5041 unless it is in the loopback net.
5042 IPv6 addresses are tagged with "IPv6:" before the address.
5044 The IP address of the interface of an outgoing connection
5045 unless it is in the loopback net.
5046 IPv6 addresses are tagged with "IPv6:" before the address.
5048 The IP family of the interface of an incoming connection
5049 unless it is in the loopback net.
5050 .ip ${if_family_out}
5051 The IP family of the interface of an outgoing connection
5052 unless it is in the loopback net.
5054 The hostname associated with the interface of an incoming connection.
5055 This macro can be used for
5056 SmtpGreetingMessage and HReceived for virtual hosting.
5059 O SmtpGreetingMessage=$?{if_name}${if_name}$|$j$. MTA
5062 The name of the interface of an outgoing connection.
5064 The current load average.
5066 The address part of the resolved triple of the address given for the
5069 Defined in the SMTP server only.
5071 The host from the resolved triple of the address given for the
5074 Defined in the SMTP server only.
5076 The mailer from the resolved triple of the address given for the
5079 Defined in the SMTP server only.
5081 The value of the Message-Id: header.
5083 The value of the SIZE= parameter,
5084 i.e., usually the size of the message (in an ESMTP dialogue),
5085 before the message has been collected, thereafter
5086 the message size as computed by
5088 (and can be used in check_compat).
5090 The number of bad recipients for a single message.
5092 The number of validated recipients for a single message.
5093 Note: since recipient validation happens after
5095 has been called, the value in this ruleset
5096 is one less than what might be expected.
5098 The number of delivery attempts.
5100 The current operation mode (from the
5104 The quarantine reason for the envelope,
5105 if it is quarantined.
5106 .ip ${queue_interval}
5107 The queue run interval given by the
5113 .b ${queue_interval}
5117 The address part of the resolved triple of the address given for the
5120 Defined in the SMTP server only after a RCPT command.
5122 The host from the resolved triple of the address given for the
5125 Defined in the SMTP server only after a RCPT command.
5127 The mailer from the resolved triple of the address given for the
5130 Defined in the SMTP server only after a RCPT command.
5132 The address of the server of the current outgoing SMTP connection.
5133 For LMTP delivery the macro is set to the name of the mailer.
5135 The name of the server of the current outgoing SMTP or LMTP connection.
5139 function, i.e., the number of seconds since 0 hours, 0 minutes,
5140 0 seconds, January 1, 1970, Coordinated Universal Time (UTC).
5142 The TLS/SSL version used for the connection, e.g., TLSv1, SSLv3, SSLv2;
5143 defined after STARTTLS has been used.
5145 The total number of incoming connections over the time interval specified
5146 by ConnectionRateWindowSize.
5148 The result of the verification of the presented cert;
5149 only defined after STARTTLS has been used (or attempted).
5150 Possible values are:
5153 OK verification succeeded.
5154 NO no cert presented.
5155 NOT no cert requested.
5156 FAIL cert presented but could not be verified,
5157 e.g., the signing CA is missing.
5158 NONE STARTTLS has not been performed.
5159 TEMP temporary error occurred.
5160 PROTOCOL some protocol error occurred
5161 at the ESMTP level (not TLS).
5162 SOFTWARE STARTTLS handshake failed,
5163 which is a fatal error for this session,
5164 the e-mail will be queued.
5167 There are three types of dates that can be used.
5172 macros are in RFC 822 format;
5174 is the time as extracted from the
5180 is the current date and time
5181 (used for postmarks).
5184 line is found in the incoming message,
5186 is set to the current time also.
5189 macro is equivalent to the
5200 are set to the identity of this host.
5202 tries to find the fully qualified name of the host
5204 it does this by calling
5206 to get the current hostname
5207 and then passing that to
5208 .i gethostbyname (3)
5209 which is supposed to return the canonical version of that host name.\**
5211 \**For example, on some systems
5215 which would be mapped to
5220 Assuming this is successful,
5222 is set to the fully qualified name
5225 is set to the domain part of the name
5226 (everything after the first dot).
5229 macro is set to the first word
5230 (everything before the first dot)
5231 if you have a level 5 or higher configuration file;
5232 otherwise, it is set to the same value as
5234 If the canonification is not successful,
5235 it is imperative that the config file set
5237 to the fully qualified domain name\**.
5239 \**Older versions of sendmail didn't pre-define
5241 at all, so up until 8.6,
5250 macro is the id of the sender
5251 as originally determined;
5252 when mailing to a specific host
5255 macro is set to the address of the sender
5257 relative to the recipient.
5260 .q bollard@matisse.CS.Berkeley.EDU
5262 .q vangogh.CS.Berkeley.EDU
5270 .q eric@vangogh.CS.Berkeley.EDU.
5274 macro is set to the full name of the sender.
5275 This can be determined in several ways.
5276 It can be passed as flag to
5278 It can be defined in the
5280 environment variable.
5281 The third choice is the value of the
5283 line in the header if it exists,
5284 and the fourth choice is the comment field
5288 If all of these fail,
5289 and if the message is being originated locally,
5290 the full name is looked up in the
5300 macros get set to the host, user, and home directory
5303 The first two are set from the
5307 part of the rewriting rules, respectively.
5313 macros are used to create unique strings
5319 macro is set to the queue id on this host;
5320 if put into the timestamp line
5321 it can be extremely useful for tracking messages.
5324 macro is set to be the version number of
5326 this is normally put in timestamps
5327 and has been proven extremely useful for debugging.
5333 i.e., the number of times this message has been processed.
5334 This can be determined
5337 flag on the command line
5338 or by counting the timestamps in the message.
5344 fields are set to the protocol used to communicate with
5346 and the sending hostname.
5347 They can be set together using the
5349 command line flag or separately using the
5357 is set to a validated sender host name.
5358 If the sender is running an RFC 1413 compliant IDENT server
5359 and the receiver has the IDENT protocol turned on,
5360 it will include the user name on that host.
5368 are set to the name, address, and port number of the SMTP client
5372 These can be used in the
5376 deferred evaluation form, of course!).
5377 .sh 2 "C and F \*- Define Classes"
5379 Classes of phrases may be defined
5380 to match on the left hand side of rewriting rules,
5383 is a sequence of characters that does not contain space characters.
5385 a class of all local names for this site
5387 so that attempts to send to oneself
5389 These can either be defined directly in the configuration file
5390 or read in from another file.
5391 Classes are named as a single letter or a word in {braces}.
5392 Class names beginning with lower case letters
5393 and special characters are reserved for system use.
5394 Classes defined in config files may be given names
5395 from the set of upper case letters for short names
5396 or beginning with an upper case letter for long names.
5411 .i c\|[mapkey]@mapclass:mapspec
5413 The first form defines the class
5415 to match any of the named words.
5423 the contents of class
5427 It is permissible to split them among multiple lines;
5428 for example, the two forms:
5439 read the elements of the class
5445 .i "map specification" .
5446 Each element should be listed on a separate line.
5447 To specify an optional file, use ``\-o'' between the class
5448 name and the file name, e.g.,
5450 Fc \-o /path/to/file
5452 If the file can't be used,
5454 will not complain but silently ignore it.
5455 The map form should be an optional map key, an at sign,
5456 and a map class followed by the specification for that map.
5459 F{VirtHosts}@ldap:\-k (&(objectClass=virtHosts)(host=*)) \-v host
5460 F{MyClass}foo@hash:/etc/mail/classes
5464 from an LDAP map lookup and
5466 from a hash database map lookup of the
5468 There is also a built-in schema that can be accessed by only specifying:
5473 This will tell sendmail to use the default schema:
5475 \-k (&(objectClass=sendmailMTAClass)
5476 (sendmailMTAClassName=\c
5478 (|(sendmailMTACluster=${sendmailMTACluster})
5479 (sendmailMTAHost=$j)))
5480 \-v sendmailMTAClassValue
5482 Note that the lookup is only done when sendmail is initially started.
5484 Elements of classes can be accessed in rules using
5490 (match entries not in class)
5491 only matches a single word;
5492 multi-word entries in the class are ignored in this context.
5494 Some classes have internal meaning to
5498 .\"A set of Content-Types that will not have the newline character
5499 .\"translated to CR-LF before encoding into base64 MIME.
5500 .\"The class can have major times
5505 .\".q application/octet-stream ).
5506 .\"The class is initialized with
5507 .\".q application/octet-stream ,
5513 contains the Content-Transfer-Encodings that can be 8\(->7 bit encoded.
5514 It is predefined to contain
5520 set to be the same as
5522 that is, the UUCP node name.
5524 set to the set of domains by which this host is known,
5528 can be set to the set of MIME body types
5529 that can never be eight to seven bit encoded.
5531 .q multipart/signed .
5536 are never encoded directly.
5537 Multipart messages are always handled recursively.
5538 The handling of message/* messages
5539 are controlled by class
5542 A set of Content-Types that will never be encoded as base64
5543 (if they have to be encoded, they will be encoded as quoted-printable).
5544 It can have primary types
5550 The class is initialized to have
5554 contains the set of subtypes of message that can be treated recursively.
5555 By default it contains only
5559 types cannot be 8\(->7 bit encoded.
5560 If a message containing eight bit data is sent to a seven bit host,
5561 and that message cannot be encoded into seven bits,
5562 it will be stripped to 7 bits.
5564 set to the set of trusted users by the
5567 If you want to read trusted users from a file, use
5571 set to be the set of all names
5572 this host is known by.
5573 This can be used to match local hostnames.
5574 .ip $={persistentMacros}
5575 set to the macros that should be saved across queue runs.
5576 Care should be taken when adding macro names to this class.
5579 can be compiled to allow a
5584 This lets you do simplistic parsing of text files.
5585 For example, to read all the user names in your system
5587 file into a class, use
5591 which reads every line up to the first colon.
5592 .sh 2 "M \*- Define Mailer"
5594 Programs and interfaces to mailers
5595 are defined in this line.
5606 is the name of the mailer
5607 (used internally only)
5610 pairs define attributes of the mailer.
5614 Path The pathname of the mailer
5615 Flags Special flags for this mailer
5616 Sender Rewriting set(s) for sender addresses
5617 Recipient Rewriting set(s) for recipient addresses
5618 recipients Maximum number of recipients per connection
5619 Argv An argument vector to pass to this mailer
5620 Eol The end-of-line string for this mailer
5621 Maxsize The maximum message length to this mailer
5622 maxmessages The maximum message deliveries per connection
5623 Linelimit The maximum line length in the message body
5624 Directory The working directory for the mailer
5625 Userid The default user and group id to run as
5626 Nice The nice(2) increment for the mailer
5627 Charset The default character set for 8-bit characters
5628 Type Type information for DSN diagnostics
5629 Wait The maximum time to wait for the mailer
5630 Queuegroup The default queue group for the mailer
5631 / The root directory for the mailer
5633 Only the first character of the field name is checked
5634 (it's case-sensitive).
5636 The following flags may be set in the mailer description.
5637 Any other flags may be used freely
5638 to conditionally assign headers to messages
5639 destined for particular mailers.
5640 Flags marked with \(dg
5641 are not interpreted by the
5644 these are the conventionally used to correlate to the flags portion
5648 Flags marked with \(dd
5649 apply to the mailers for the sender address
5650 rather than the usual recipient mailers.
5653 Run Extended SMTP (ESMTP) protocol (defined in RFCs 1869, 1652, and 1870).
5654 This flag defaults on if the SMTP greeting message includes the word
5657 Look up the user (address) part of the resolved mailer triple,
5658 in the alias database.
5659 Normally this is only set for local mailers.
5661 Force a blank line on the end of a message.
5662 This is intended to work around some stupid versions of
5664 that require a blank line, but do not provide it themselves.
5665 It would not normally be used on network mail.
5667 Strip leading backslashes (\e) off of the address;
5668 this is a subset of the functionality of the
5672 Do not include comments in addresses.
5673 This should only be used if you have to work around
5674 a remote mailer that gets confused by comments.
5675 This strips addresses of the form
5676 .q "Phrase <address>"
5678 .q "address (Comment)"
5684 from a mailer with this flag set,
5685 any addresses in the header that do not have an at sign
5688 after being rewritten by ruleset three
5691 clause from the sender envelope address
5693 This allows mail with headers of the form:
5696 To: userb@hostb, userc
5701 To: userb@hostb, userc@hosta
5704 However, it doesn't really work reliably.
5706 Do not include angle brackets around route-address syntax addresses.
5707 This is useful on mailers that are going to pass addresses to a shell
5708 that might interpret angle brackets as I/O redirection.
5709 However, it does not protect against other shell metacharacters.
5710 Therefore, passing addresses to a shell should not be considered secure.
5716 This mailer is expensive to connect to,
5717 so try to avoid connecting normally;
5718 any necessary connection will occur during a queue run.
5722 Escape lines beginning with
5724 in the message with a `>' sign.
5730 but only if this is a network forward operation
5732 the mailer will give an error
5733 if the executing user
5734 does not have special permissions).
5742 sends internally generated email (e.g., error messages)
5743 using the null return address
5744 as required by RFC 1123.
5745 However, some mailers don't accept a null return address.
5751 from obeying the standards;
5752 error messages will be sent as from the MAILER-DAEMON
5753 (actually, the value of the
5757 Upper case should be preserved in host names
5758 (the $@ portion of the mailer triplet resolved from ruleset 0)
5761 Do User Database rewriting on envelope sender address.
5763 This mailer will be speaking SMTP
5767 as such it can use special protocol features.
5768 This flag should not be used except for debugging purposes
5773 Do User Database rewriting on recipients as well as senders.
5777 connects to a host via SMTP,
5778 it checks to make sure that this isn't accidently the same host name
5781 is misconfigured or if a long-haul network interface is set in loopback mode.
5782 This flag disables the loopback check.
5783 It should only be used under very unusual circumstances.
5785 Currently unimplemented.
5786 Reserved for chunking.
5788 This mailer is local
5790 final delivery will be performed).
5792 Limit the line lengths as specified in RFC 821.
5793 This deprecated option should be replaced by the
5796 For historic reasons, the
5802 This mailer can send to multiple users
5809 part of the mailer definition,
5810 that field will be repeated as necessary
5811 for all qualifying users.
5812 Removing this flag can defeat duplicate supression on a remote site
5813 as each recipient is sent in a separate transaction.
5819 Do not insert a UNIX-style
5821 line on the front of the message.
5823 Always run as the owner of the recipient mailbox.
5826 runs as the sender for locally generated mail
5829 (actually, the user specified in the
5832 when delivering network mail.
5833 The normal behavior is required by most local mailers,
5834 which will not allow the envelope sender address
5835 to be set unless the mailer is running as daemon.
5836 This flag is ignored if the
5840 Use the route-addr style reverse-path in the SMTP
5843 rather than just the return address;
5844 although this is required in RFC 821 section 3.1,
5845 many hosts do not process reverse-paths properly.
5846 Reverse-paths are officially discouraged by RFC 1123.
5852 When an address that resolves to this mailer is verified
5853 (SMTP VRFY command),
5854 generate 250 responses instead of 252 responses.
5855 This will imply that the address is local.
5863 Open SMTP connections from a
5868 except on UNIX machines,
5869 so it is unclear that this adds anything.
5871 must be running as root to be able to use this flag.
5873 Strip quote characters (" and \e) off of the address
5874 before calling the mailer.
5876 Don't reset the userid
5877 before calling the mailer.
5878 This would be used in a secure environment
5882 This could be used to avoid forged addresses.
5885 field is also specified,
5886 this flag causes the effective user id to be set to that user.
5888 Upper case should be preserved in user names for this mailer. Standards
5889 require preservation of case in the local part of addresses, except for
5890 those address for which your system accepts responsibility.
5891 RFC 2142 provides a long list of addresses which should be case
5893 If you use this flag, you may be violating RFC 2142.
5894 Note that postmaster is always treated as a case insensitive address
5895 regardless of this flag.
5897 This mailer wants UUCP-style
5900 .q "remote from <host>"
5903 The user must have a valid account on this machine,
5907 If not, the mail is bounced.
5911 This is required to get
5915 Ignore long term host status information (see Section
5916 "Persistent Host Status Information").
5922 This mailer wants to use the hidden dot algorithm as specified in RFC 821;
5923 basically, any line beginning with a dot will have an extra dot prepended
5924 (to be stripped at the other end).
5925 This insures that lines in the message containing a dot
5926 will not terminate the message prematurely.
5928 Run Local Mail Transfer Protocol (LMTP)
5931 and the local mailer.
5932 This is a variant on SMTP
5934 that is specifically designed for delivery to a local mailbox.
5936 Apply DialDelay (if set) to this mailer.
5938 Don't look up MX records for hosts sent via SMTP/LMTP.
5943 Don't send null characters ('\\0') to this mailer.
5945 Don't use ESMTP even if offered; this is useful for broken
5946 systems that offer ESMTP but fail on EHLO (without recovering
5947 when HELO is tried next).
5949 Extend the list of characters converted to =XX notation
5950 when converting to Quoted-Printable
5951 to include those that don't map cleanly between ASCII and EBCDIC.
5952 Useful if you have IBM mainframes on site.
5954 If no aliases are found for this address,
5955 pass the address through ruleset 5 for possible alternate resolution.
5956 This is intended to forward the mail to an alternate delivery spot.
5958 Strip headers to seven bits.
5960 Strip all output to seven bits.
5961 This is the default if the
5964 Note that clearing this option is not
5965 sufficient to get full eight bit data passed through
5969 option is set, this is essentially always set,
5970 since the eighth bit was stripped on input.
5971 Note that this option will only impact messages
5972 that didn't have 8\(->7 bit MIME conversions performed.
5975 it is acceptable to send eight bit data to this mailer;
5976 the usual attempt to do 8\(->7 bit MIME conversions will be bypassed.
5981 7\(->8 bit MIME conversions.
5982 These conversions are limited to text/plain data.
5984 Check addresses to see if they begin
5986 if they do, convert them to the
5990 Check addresses to see if they begin with a `|';
5991 if they do, convert them to the
5995 Check addresses to see if they begin with a `/';
5996 if they do, convert them to the
6000 Look up addresses in the user database.
6002 Do not attempt delivery on initial receipt of a message
6004 unless the queued message is selected
6005 using one of the -qI/-qR/-qS queue run modifiers
6008 Configuration files prior to level 6
6009 assume the `A', `w', `5', `:', `|', `/', and `@' options
6013 The mailer with the special name
6015 can be used to generate a user error.
6016 The (optional) host field is an exit status to be returned,
6017 and the user field is a message to be printed.
6018 The exit status may be numeric or one of the values
6019 USAGE, NOUSER, NOHOST, UNAVAILABLE, SOFTWARE, TEMPFAIL, PROTOCOL, or CONFIG
6020 to return the corresponding EX_ exit code,
6021 or an enhanced error code as described in RFC 1893,
6023 Enhanced Mail System Status Codes.
6024 For example, the entry:
6026 $#error $@ NOHOST $: Host unknown in this domain
6028 on the RHS of a rule
6029 will cause the specified error to be generated
6032 exit status to be returned
6034 This mailer is only functional in rulesets 0, 5,
6035 or one of the check_* rulesets.
6036 The host field can also contain the special token
6038 which instructs sendmail to quarantine the current message.
6040 The mailer with the special name
6042 causes any mail sent to it to be discarded
6043 but otherwise treated as though it were successfully delivered.
6044 This mailer cannot be used in ruleset 0,
6045 only in the various address checking rulesets.
6050 be defined in every configuration file.
6051 This is used to deliver local mail,
6052 and is treated specially in several ways.
6053 Additionally, three other mailers named
6058 may be defined to tune the delivery of messages to programs,
6060 and :include: lists respectively.
6063 Mprog, P=/bin/sh, F=lsoDq9, T=DNS/RFC822/X-Unix, A=sh \-c $u
6064 M*file*, P=[FILE], F=lsDFMPEouq9, T=DNS/RFC822/X-Unix, A=FILE $u
6065 M*include*, P=/dev/null, F=su, A=INCLUDE $u
6068 Builtin pathnames are [FILE] and [IPC], the former is used for
6069 delivery to files, the latter for delivery via interprocess communication.
6070 For mailers that use [IPC] as pathname the argument vector (A=)
6071 must start with TCP or FILE for delivery via a TCP or a Unix domain socket.
6072 If TCP is used, the second argument must be the name of the host
6074 Optionally a third argument can be used to specify a port,
6075 the default is smtp (port 25).
6076 If FILE is used, the second argument must be the name of
6077 the Unix domain socket.
6079 If the argument vector does not contain $u then
6081 will speak SMTP (or LMTP if the mailer flag z is specified) to the mailer.
6083 If no Eol field is defined, then the default is "\\r\\n" for
6084 SMTP mailers and "\\n" of others.
6086 The Sender and Recipient rewriting sets
6087 may either be a simple ruleset id
6088 or may be two ids separated by a slash;
6089 if so, the first rewriting set is applied to envelope
6091 and the second is applied to headers.
6092 Setting any value to zero disables corresponding mailer-specific rewriting.
6095 is actually a colon-separated path of directories to try.
6096 For example, the definition
6098 first tries to execute in the recipient's home directory;
6099 if that is not available,
6100 it tries to execute in the root of the filesystem.
6101 This is intended to be used only on the
6104 since some shells (such as
6106 refuse to execute if they cannot read the current directory.
6107 Since the queue directory is not normally readable by unprivileged users
6109 scripts as recipients can fail.
6112 specifies the default user and group id to run as,
6118 mailer flag is also specified,
6119 this user and group will be set as the
6120 effective uid and gid for the process.
6121 This may be given as
6123 to set both the user and group id;
6124 either may be an integer or a symbolic name to be looked up
6130 If only a symbolic user name is specified,
6133 file for that user is used as the group id.
6136 is used when converting a message to MIME;
6137 this is the character set used in the
6138 Content-Type: header.
6139 If this is not set, the
6142 and if that is not set, the value
6146 this field applies to the sender's mailer,
6147 not the recipient's mailer.
6148 For example, if the envelope sender address
6149 lists an address on the local network
6150 and the recipient is on an external network,
6151 the character set will be set from the Charset= field
6152 for the local network mailer,
6153 not that of the external network mailer.
6156 sets the type information
6157 used in MIME error messages
6160 It is actually three values separated by slashes:
6161 the MTA-type (that is, the description of how hosts are named),
6162 the address type (the description of e-mail addresses),
6163 and the diagnostic type (the description of error diagnostic codes).
6164 Each of these must be a registered value
6168 .q dns/rfc822/smtp .
6170 The m= field specifies the maximum number of messages
6171 to attempt to deliver on a single SMTP or LMTP connection.
6172 The default is infinite.
6174 The r= field specifies the maximum number of recipients
6175 to attempt to deliver in a single envelope.
6178 The /= field specifies a new root directory for the mailer. The path is
6179 macro expanded and then passed to the
6181 system call. The root directory is changed before the Directory field is
6182 consulted or the uid is changed.
6184 The Wait= field specifies the maximum time to wait for the
6185 mailer to return after sending all data to it.
6186 This applies to mailers that have been forked by
6189 The Queuegroup= field specifies the default queue group in which
6190 received mail should be queued.
6191 This can be overridden by other means as explained in section
6192 ``Queue Groups and Queue Directories''.
6193 .sh 2 "H \*- Define Header"
6195 The format of the header lines that
6197 inserts into the message
6201 The syntax of this line is one of the following:
6228 Continuation lines in this spec
6229 are reflected directly into the outgoing message.
6232 is macro-expanded before insertion into the message.
6235 (surrounded by question marks)
6237 at least one of the specified flags
6238 must be stated in the mailer definition
6239 for this header to be automatically output.
6242 (surrounded by question marks)
6244 the header will be automatically output
6245 if the macro is set.
6246 The macro may be set using any of the normal methods,
6249 storage map in a ruleset.
6250 If one of these headers is in the input
6251 it is reflected to the output
6252 regardless of these flags or macros.
6256 is used to set a header, then it is useful to add that macro to class
6257 .i $={persistentMacros}
6258 which consists of the macros that should be saved across queue runs.
6260 Some headers have special semantics
6261 that will be described later.
6263 A secondary syntax allows validation of headers as they are being read.
6264 To enable validation, use:
6277 is called for the specified
6281 to reject or quarantine the message or
6283 to discard the message
6287 The ruleset receives the header field-body as argument,
6288 i.e., not the header field-name; see also
6289 ${hdr_name} and ${currHeader}.
6290 The header is treated as a structured field,
6292 text in parentheses is deleted before processing,
6293 unless the second form
6296 Note: only one ruleset can be associated with a header;
6298 will silently ignore multiple entries.
6300 For example, the configuration lines:
6302 HMessage-Id: $>CheckMessageId
6306 R$* $#error $: Illegal Message-Id header
6308 would refuse any message that had a Message-Id: header of any of the
6312 Message-Id: some text
6313 Message-Id: <legal text@domain> extra crud
6315 A default ruleset that is called for headers which don't have a
6316 specific ruleset defined for them can be specified by:
6330 .sh 2 "O \*- Set Option"
6332 There are a number of global options that
6333 can be set from a configuration file.
6334 Options are represented by full words;
6335 some are also representable as single characters for back compatibility.
6336 The syntax of this line is:
6349 be a space between the letter `O' and the name of the option.
6350 An older version is:
6357 is a single character.
6358 Depending on the option,
6360 may be a string, an integer,
6368 the default is TRUE),
6372 All filenames used in options should be absolute paths,
6373 i.e., starting with '/'.
6374 Relative filenames most likely cause surprises during operation
6375 (unless otherwise noted).
6377 The options supported (with the old, one character names in brackets) are:
6379 .ip "AliasFile=\fIspec, spec, ...\fP"
6381 Specify possible alias file(s).
6384 should be in the format
6392 is optional and defaults to ``implicit''.
6407 value is used as follows:
6409 \-k (&(objectClass=sendmailMTAAliasObject)
6410 (sendmailMTAAliasName=aliases)
6411 (|(sendmailMTACluster=${sendmailMTACluster})
6412 (sendmailMTAHost=$j))
6413 (sendmailMTAKey=%0))
6414 \-v sendmailMTAAliasValue
6418 is compiled, valid classes are
6420 (search through a compiled-in list of alias file types,
6421 for back compatibility),
6435 (internal symbol table \*- not normally used
6436 unless you have no other database lookup),
6438 (use a sequence of maps
6439 previously declared),
6453 searches them in order.
6454 .ip AliasWait=\fItimeout\fP
6459 (units default to minutes)
6462 entry to exist in the alias database
6464 If it does not appear in the
6466 interval issue a warning.
6469 If set, allow HELO SMTP commands that don't include a host name.
6470 Setting this violates RFC 1123 section 5.2.5,
6471 but is necessary to interoperate with several SMTP clients.
6472 If there is a value, it is still checked for legitimacy.
6473 .ip AuthMaxBits=\fIN\fP
6475 Limit the maximum encryption strength for the security layer in
6476 SMTP AUTH (SASL). Default is essentially unlimited.
6477 This allows to turn off additional encryption in SASL if
6478 STARTTLS is already encrypting the communication, because the
6479 existing encryption strength is taken into account when choosing
6480 an algorithm for the security layer.
6481 For example, if STARTTLS is used and the symmetric cipher is 3DES,
6482 then the the keylength (in bits) is 168.
6485 to 168 will disable any encryption in SASL.
6488 List of authentication mechanisms for AUTH (separated by spaces).
6489 The advertised list of authentication mechanisms will be the
6490 intersection of this list and the list of available mechanisms as
6491 determined by the Cyrus SASL library.
6492 If STARTTLS is active, EXTERNAL will be added to this list.
6493 In that case, the value of {cert_subject} is used as authentication id.
6496 List of options for SMTP AUTH consisting of single characters
6497 with intervening white space or commas.
6500 A Use the AUTH= parameter for the MAIL FROM
6501 command only when authentication succeeded.
6502 This can be used as a workaround for broken
6503 MTAs that do not implement RFC 2554 correctly.
6504 a protection from active (non-dictionary) attacks
6505 during authentication exchange.
6506 c require mechanisms which pass client credentials,
6507 and allow mechanisms which can pass credentials
6509 d don't permit mechanisms susceptible to passive
6511 f require forward secrecy between sessions
6512 (breaking one won't help break next).
6513 m require mechanisms which provide mutual authentication
6514 (only available if using Cyrus SASL v2 or later).
6515 p don't permit mechanisms susceptible to simple
6516 passive attack (e.g., PLAIN, LOGIN), unless a
6517 security layer is active.
6518 y don't permit mechanisms that allow anonymous login.
6520 The first option applies to sendmail as a client, the others to a server.
6525 would disallow ANONYMOUS as AUTH mechanism and would
6526 allow PLAIN and LOGIN only if a security layer (e.g.,
6527 provided by STARTTLS) is already active.
6528 The options 'a', 'c', 'd', 'f', 'p', and 'y' refer to properties of the
6529 selected SASL mechanisms.
6530 Explanations of these properties can be found in the Cyrus SASL documentation.
6533 The authentication realm that is passed to the Cyrus SASL library.
6534 If no realm is specified,
6537 .ip BadRcptThrottle=\fIN\fP
6539 If set and the specified number of recipients in a single SMTP
6540 transaction have been rejected, sleep for one second after each subsequent
6541 RCPT command in that transaction.
6542 .ip BlankSub=\fIc\fP
6544 Set the blank substitution character to
6546 Unquoted spaces in addresses are replaced by this character.
6547 Defaults to space (i.e., no change is made).
6550 Path to directory with certificates of CAs.
6551 This directory directory must contain the hashes of each CA certificate
6552 as filenames (or as links to them).
6555 File containing one or more CA certificates;
6556 see section about STARTTLS for more information.
6559 Validate the RHS of aliases when rebuilding the alias database.
6560 .ip CheckpointInterval=\fIN\fP
6562 Checkpoints the queue every
6566 If your system crashes during delivery to a large list,
6567 this prevents retransmission to any but the last
6570 .ip ClassFactor=\fIfact\fP
6574 is multiplied by the message class
6575 (determined by the Precedence: field in the user header
6578 lines in the configuration file)
6579 and subtracted from the priority.
6580 Thus, messages with a higher Priority: will be favored.
6584 File containing the certificate of the client, i.e., this certificate
6587 acts as client (for STARTTLS).
6590 File containing the private key belonging to the client certificate
6594 .ip ClientPortOptions=\fIoptions\fP
6596 Set client SMTP options.
6599 pairs separated by commas.
6603 Port Name/number of source port for connection (defaults to any free port)
6604 Addr Address mask (defaults INADDR_ANY)
6605 Family Address family (defaults to INET)
6606 SndBufSize Size of TCP send buffer
6607 RcvBufSize Size of TCP receive buffer
6608 Modifier Options (flags) for the client
6612 mask may be a numeric address in dot notation
6615 can be the following character:
6618 h use name of interface for HELO command
6619 A don't use AUTH when sending e-mail
6620 S don't use STARTTLS when sending e-mail
6622 If ``h'' is set, the name corresponding to the outgoing interface
6623 address (whether chosen via the Connection parameter or
6624 the default) is used for the HELO/EHLO command.
6625 However, the name must not start with a square bracket
6626 and it must contain at least one dot.
6627 This is a simple test whether the name is not
6628 an IP address (in square brackets) but a qualified hostname.
6629 Note that multiple ClientPortOptions settings are allowed
6630 in order to give settings for each protocol family
6631 (e.g., one for Family=inet and one for Family=inet6).
6632 A restriction placed on one family only affects
6633 outgoing connections on that particular family.
6636 If set, colons are acceptable in e-mail addresses
6639 If not set, colons indicate the beginning of a RFC 822 group construct
6641 .q "groupname: member1, member2, ... memberN;" ).
6642 Doubled colons are always acceptable
6645 and proper route-addr nesting is understood
6647 .q <@relay:user@host> ).
6648 Furthermore, this option defaults on if the configuration version level
6649 is less than 6 (for back compatibility).
6650 However, it must be off for full compatibility with RFC 822.
6651 .ip ConnectionCacheSize=\fIN\fP
6653 The maximum number of open connections that will be cached at a time.
6655 This delays closing the current connection until
6656 either this invocation of
6658 needs to connect to another host
6660 Setting it to zero defaults to the old behavior,
6661 that is, connections are closed immediately.
6662 Since this consumes file descriptors,
6663 the connection cache should be kept small:
6664 4 is probably a practical maximum.
6665 .ip ConnectionCacheTimeout=\fItimeout\fP
6667 The maximum amount of time a cached connection will be permitted to idle
6669 If this time is exceeded,
6670 the connection is immediately closed.
6671 This value should be small (on the order of ten minutes).
6674 uses a cached connection,
6675 it always sends a RSET command
6676 to check the connection;
6677 if this fails, it reopens the connection.
6678 This keeps your end from failing if the other end times out.
6679 The point of this option is to be a good network neighbor
6680 and avoid using up excessive resources
6682 The default is five minutes.
6683 .ip ConnectOnlyTo=\fIaddress\fP
6686 override the connection address (for testing purposes).
6687 .ip ConnectionRateThrottle=\fIN\fP
6689 If set to a positive value,
6692 incoming connections in a one second period per daemon.
6693 This is intended to flatten out peaks
6694 and allow the load average checking to cut in.
6695 Defaults to zero (no limits).
6696 .ip ConnectionRateWindowSize=\fIN\fP
6698 Define the length of the interval for which
6699 the number of incoming connections is maintained.
6700 The default is 60 seconds.
6701 .ip ControlSocketName=\fIname\fP
6703 Name of the control socket for daemon management.
6706 daemon can be controlled through this named socket.
6707 Available commands are:
6716 command returns the current number of daemon children,
6717 the maximum number of daemon children,
6718 the free disk space (in blocks) of the queue directory,
6719 and the load average of the machine expressed as an integer.
6720 If not set, no control socket will be available.
6721 Solaris and pre-4.4BSD kernel users should see the note in sendmail/README .
6722 .ip CRLFile=\fIname\fP
6724 Name of file that contains certificate
6725 revocation status, useful for X.509v3 authentication.
6726 CRL checking requires at least OpenSSL version 0.9.7.
6727 Note: if a CRLFile is specified but the file is unusable,
6728 STARTTLS is disabled.
6730 Possible values are:
6734 1 use 1024 bit prime
6735 none do not use Diffie-Hellman
6736 NAME load prime from file
6738 This is only required if a ciphersuite containing DSA/DH is used.
6739 If ``5'' is selected, then precomputed, fixed primes are used.
6740 This is the default for the client side.
6741 If ``1'' is selected, then prime values are computed during startup.
6742 This is the default for the server side.
6743 Note: this operation can take a significant amount of time on a
6744 slow machine (several seconds), but it is only done once at startup.
6745 If ``none'' is selected, then TLS ciphersuites containing DSA/DH
6747 If a file name is specified (which must be an absolute path),
6748 then the primes are read from it.
6749 .ip DaemonPortOptions=\fIoptions\fP
6751 Set server SMTP options.
6753 .b DaemonPortOptions
6754 leads to an additional incoming socket.
6761 Name User-definable name for the daemon (defaults to "Daemon#")
6762 Port Name/number of listening port (defaults to "smtp")
6763 Addr Address mask (defaults INADDR_ANY)
6764 Family Address family (defaults to INET)
6765 InputMailFilters List of input mail filters for the daemon
6766 Listen Size of listen queue (defaults to 10)
6767 Modifier Options (flags) for the daemon
6768 SndBufSize Size of TCP send buffer
6769 RcvBufSize Size of TCP receive buffer
6770 children maximum number of children per daemon, see \fBMaxDaemonChildren\fP.
6771 DeliveryMode Delivery mode per daemon, see \fBDeliveryMode\fP.
6772 refuseLA RefuseLA per daemon
6773 delayLA DelayLA per daemon
6774 queueLA QueueLA per daemon
6778 key is used for error messages and logging.
6781 mask may be a numeric address in dot notation
6785 key defaults to INET (IPv4).
6786 IPv6 users who wish to also accept IPv6 connections
6787 should add additional Family=inet6
6788 .b DaemonPortOptions
6792 key overrides the default list of input mail filters listed in the
6795 If multiple input mail filters are required, they must be separated
6796 by semicolons (not commas).
6798 can be a sequence (without any delimiters)
6799 of the following characters:
6802 a always require authentication
6803 b bind to interface through which mail has been received
6804 c perform hostname canonification (.cf)
6805 f require fully qualified hostname (.cf)
6806 s Run smtps (SMTP over SSL) instead of smtp
6807 u allow unqualified addresses (.cf)
6808 A disable AUTH (overrides 'a' modifier)
6809 C don't perform hostname canonification
6810 E disallow ETRN (see RFC 2476)
6811 O optional; if opening the socket fails ignore it
6812 S don't offer STARTTLS
6814 That is, one way to specify a message submission agent (MSA) that
6815 always requires authentication is:
6817 O DaemonPortOptions=Name=MSA, Port=587, M=Ea
6819 The modifiers that are marked with "(.cf)" have only
6820 effect in the standard configuration file, in which
6821 they are available via
6822 .b ${daemon_flags} .
6825 use the ``a'' modifier on a public accessible MTA!
6826 It should only be used for a MSA that is accessed by authorized
6827 users for initial mail submission.
6828 Users must authenticate to use a MSA which has this option turned on.
6829 The flags ``c'' and ``C'' can change the default for
6830 hostname canonification in the
6833 See the relevant documentation for
6834 .sm FEATURE(nocanonify) .
6835 The modifier ``f'' disallows addresses of the form
6837 unless they are submitted directly.
6838 The flag ``u'' allows unqualified sender addresses,
6839 i.e., those without @host.
6840 ``b'' forces sendmail to bind to the interface
6841 through which the e-mail has been
6842 received for the outgoing connection.
6845 only if outgoing mail can be routed through the incoming connection's
6846 interface to its destination. No attempt is made to catch problems due to a
6847 misconfiguration of this parameter, use it only for virtual hosting
6848 where each virtual interface can connect to every possible location.
6849 This will also override possible settings via
6850 .b ClientPortOptions.
6853 will listen on a new socket
6854 for each occurence of the
6855 .b DaemonPortOptions
6856 option in a configuration file.
6857 The modifier ``O'' causes sendmail to ignore a socket
6858 if it can't be opened.
6859 This applies to failures from the socket(2) and bind(2) calls.
6862 Filename that contains default authentication information for outgoing
6863 connections. This file must contain the user id, the authorization id,
6864 the password (plain text), the realm and the list of mechanisms to use
6865 on separate lines and must be readable by
6866 root (or the trusted user) only.
6867 If no realm is specified,
6870 If no mechanisms are specified, the list given by
6873 Notice: this option is deprecated and will be removed in future versions.
6874 Moreover, it doesn't work for the MSP since it can't read the file
6875 (the file must not be group/world-readable otherwise
6878 Use the authinfo ruleset instead which provides more control over
6879 the usage of the data anyway.
6880 .ip DefaultCharSet=\fIcharset\fP
6882 When a message that has 8-bit characters but is not in MIME format
6883 is converted to MIME
6884 (see the EightBitMode option)
6885 a character set must be included in the Content-Type: header.
6886 This character set is normally set from the Charset= field
6887 of the mailer descriptor.
6888 If that is not set, the value of this option is used.
6889 If this option is not set, the value
6892 .ip DataFileBufferSize=\fIthreshold\fP
6897 before a memory-based
6900 The default is 4096 bytes.
6901 .ip DeadLetterDrop=\fIfile\fP
6903 Defines the location of the system-wide dead.letter file,
6904 formerly hardcoded to /usr/tmp/dead.letter.
6905 If this option is not set (the default),
6906 sendmail will not attempt to save to a system-wide dead.letter file
6908 it cannot bounce the mail to the user or postmaster.
6909 Instead, it will rename the qf file
6910 as it has in the past
6911 when the dead.letter file could not be opened.
6912 .ip DefaultUser=\fIuser:group\fP
6914 Set the default userid for mailers to
6921 (as opposed to a numeric user id)
6922 the default group listed in the /etc/passwd file for that user is used
6923 as the default group.
6931 flag in the mailer definition
6932 will run as this user.
6934 The value can also be given as a symbolic user name.\**
6938 option has been combined into the
6942 .ip DelayLA=\fILA\fP
6944 When the system load average exceeds
6947 will sleep for one second on most SMTP commands and
6948 before accepting connections.
6949 .ip DeliverByMin=\fItime\fP
6951 Set minimum time for Deliver By SMTP Service Extension (RFC 2852).
6952 If 0, no time is listed, if less than 0, the extension is not offered,
6953 if greater than 0, it is listed as minimum time
6954 for the EHLO keyword DELIVERBY.
6955 .ip DeliveryMode=\fIx\fP
6962 i Deliver interactively (synchronously)
6963 b Deliver in background (asynchronously)
6964 q Just queue the message (deliver during queue run)
6965 d Defer delivery and all map lookups (deliver during queue run)
6967 Defaults to ``b'' if no option is specified,
6968 ``i'' if it is specified but given no argument
6969 (i.e., ``Od'' is equivalent to ``Odi'').
6972 command line flag sets this to
6974 Note: for internal reasons,
6976 if a milter is enabled which can reject or delete recipients.
6977 In that case the mode will be changed to ``b''.
6978 .ip DialDelay=\fIsleeptime\fP
6980 Dial-on-demand network connections can see timeouts
6981 if a connection is opened before the call is set up.
6982 If this is set to an interval and a connection times out
6983 on the first connection being attempted
6985 will sleep for this amount of time and try again.
6986 This should give your system time to establish the connection
6987 to your service provider.
6988 Units default to seconds, so
6990 uses a five second delay.
6993 This delay only applies to mailers which have the
6995 .ip DirectSubmissionModifiers=\fImodifiers\fP
6998 for direct (command line) submissions.
7001 is either "CC f" if the option
7003 is used or "c u" otherwise.
7004 Note that only the the "CC", "c", "f", and "u" flags are checked.
7005 .ip DontBlameSendmail=\fIoption,option,...\fP
7007 In order to avoid possible cracking attempts
7008 caused by world- and group-writable files and directories,
7010 does paranoid checking when opening most of its support files.
7011 If for some reason you absolutely must run with,
7016 then you will have to turn off this checking
7017 (at the cost of making your system more vulnerable to attack).
7018 The possible arguments have been described earlier.
7019 The details of these flags are described above.
7020 .\"XXX should have more here!!! XXX
7021 .b "Use of this option is not recommended."
7022 .ip DontExpandCnames
7024 The standards say that all host addresses used in a mail message
7025 must be fully canonical.
7026 For example, if your host is named
7028 and also has an alias of
7030 the former name must be used at all times.
7031 This is enforced during host name canonification
7032 ($[ ... $] lookups).
7033 If this option is set, the protocols are ignored and the
7036 However, the IETF is moving toward changing this standard,
7037 so the behavior may become acceptable.
7038 Please note that hosts downstream may still rewrite the address
7039 to be the true canonical name however.
7044 will avoid using the initgroups(3) call.
7045 If you are running NIS,
7046 this causes a sequential scan of the groups.byname map,
7047 which can cause your NIS server to be badly overloaded in a large domain.
7048 The cost of this is that the only group found for users
7049 will be their primary group (the one in the password file),
7050 which will make file access permissions somewhat more restrictive.
7051 Has no effect on systems that don't have group lists.
7052 .ip DontProbeInterfaces
7055 normally finds the names of all interfaces active on your machine
7057 and adds their name to the
7059 class of known host aliases.
7060 If you have a large number of virtual interfaces
7061 or if your DNS inverse lookups are slow
7062 this can be time consuming.
7063 This option turns off that probing.
7064 However, you will need to be certain to include all variant names
7067 class by some other mechanism.
7070 loopback interfaces (e.g., lo0) will not be probed.
7075 tries to eliminate any unnecessary explicit routes
7076 when sending an error message
7077 (as discussed in RFC 1123 \(sc 5.2.6).
7079 when sending an error message to
7081 <@known1,@known2,@known3:user@unknown>
7086 in order to make the route as direct as possible.
7089 option is set, this will be disabled,
7090 and the mail will be sent to the first address in the route,
7091 even if later addresses are known.
7092 This may be useful if you are caught behind a firewall.
7093 .ip DoubleBounceAddress=\fIerror-address\fP
7095 If an error occurs when sending an error message,
7096 send the error report
7099 because it is an error
7101 that occurs when trying to send another error
7103 to the indicated address.
7104 The address is macro expanded
7105 at the time of delivery.
7106 If not set, defaults to
7108 If set to an empty string, double bounces are dropped.
7109 .ip EightBitMode=\fIaction\fP
7111 Set handling of eight-bit data.
7112 There are two kinds of eight-bit data:
7113 that declared as such using the
7115 ESMTP declaration or the
7118 and undeclared 8-bit data, that is,
7119 input that just happens to be eight bits.
7120 There are three basic operations that can happen:
7121 undeclared 8-bit data can be automatically converted to 8BITMIME,
7122 undeclared 8-bit data can be passed as-is without conversion to MIME
7124 and declared 8-bit data can be converted to 7-bits
7125 for transmission to a non-8BITMIME mailer.
7130 .\" r Reject undeclared 8-bit data;
7131 .\" don't convert 8BITMIME\(->7BIT (``reject'')
7132 s Reject undeclared 8-bit data (``strict'')
7133 .\" do convert 8BITMIME\(->7BIT (``strict'')
7134 .\" c Convert undeclared 8-bit data to MIME;
7135 .\" don't convert 8BITMIME\(->7BIT (``convert'')
7136 m Convert undeclared 8-bit data to MIME (``mime'')
7137 .\" do convert 8BITMIME\(->7BIT (``mime'')
7138 .\" j Pass undeclared 8-bit data;
7139 .\" don't convert 8BITMIME\(->7BIT (``just send 8'')
7140 p Pass undeclared 8-bit data (``pass'')
7141 .\" do convert 8BITMIME\(->7BIT (``pass'')
7142 .\" a Adaptive algorithm: see below
7144 .\"The adaptive algorithm is to accept 8-bit data,
7145 .\"converting it to 8BITMIME only if the receiver understands that,
7146 .\"otherwise just passing it as undeclared 8-bit data;
7147 .\"8BITMIME\(->7BIT conversions are done.
7148 In all cases properly declared 8BITMIME data will be converted to 7BIT
7150 .ip ErrorHeader=\fIfile-or-message\fP
7152 Prepend error messages with the indicated message.
7153 If it begins with a slash,
7154 it is assumed to be the pathname of a file
7155 containing a message (this is the recommended setting).
7156 Otherwise, it is a literal message.
7157 The error file might contain the name, email address, and/or phone number
7158 of a local postmaster who could provide assistance
7160 If the option is missing or null,
7161 or if it names a file which does not exist or which is not readable,
7162 no message is printed.
7163 .ip ErrorMode=\fIx\fP
7165 Dispose of errors using mode
7171 p Print error messages (default)
7172 q No messages, just give exit status
7174 w Write back errors (mail if user not logged in)
7175 e Mail back errors (when applicable) and give zero exit stat always
7177 Note that the last mode,
7179 is for Berknet error processing and
7180 should not be used in normal circumstances.
7181 Note, too, that mode
7183 only applies to errors recognized before sendmail forks for
7184 background delivery.
7185 .ip FallbackMXhost=\fIfallbackhost\fP
7189 acts like a very low priority MX
7191 MX records will be looked up for this host,
7192 unless the name is surrounded by square brackets.
7193 This is intended to be used by sites with poor network connectivity.
7194 Messages which are undeliverable due to temporary address failures
7196 also go to the FallbackMXhost.
7197 .ip FallBackSmartHost=\fIhostname\fP
7199 .i FallBackSmartHost
7200 will be used in a last-ditch effort for each host.
7201 This is intended to be used by sites with "fake internal DNS",
7202 e.g., a company whose DNS accurately reflects the world
7203 inside that company's domain but not outside.
7206 If set to a value greater than zero (the default is one),
7207 it suppresses the MX lookups on addresses
7208 when they are initially sorted, i.e., for the first delivery attempt.
7209 This usually results in faster envelope splitting unless the MX records
7210 are readily available in a local DNS cache.
7211 To enforce initial sorting based on MX records set
7214 If the mail is submitted directly from the command line, then
7215 the value also limits the number of processes to deliver the envelopes;
7216 if more envelopes are created they are only queued up
7217 and must be taken care of by a queue run.
7218 Since the default submission method is via SMTP (either from a MUA
7219 or via the MSP), the value of
7221 is seldom used to limit the number of processes to deliver the envelopes.
7225 deliver each job that is run from the queue in a separate process.
7226 .ip ForwardPath=\fIpath\fP
7228 Set the path for searching for users' .forward files.
7231 Some sites that use the automounter may prefer to change this to
7233 to search a file with the same name as the user in a system directory.
7234 It can also be set to a sequence of paths separated by colons;
7236 stops at the first file it can successfully and safely open.
7238 .q /var/forward/$u:$z/.forward
7239 will search first in /var/forward/\c
7242 .i ~username /.forward
7243 (but only if the first file does not exist).
7244 .ip HeloName=\fIname\fP
7246 Set the name to be used for HELO/EHLO (instead of $j).
7249 If an outgoing mailer is marked as being expensive,
7250 don't connect immediately.
7251 .ip HostsFile=\fIpath\fP
7253 The path to the hosts database,
7256 This option is only consulted when sendmail
7257 is canonifying addresses,
7262 service switch entry.
7263 In particular, this file is
7265 used when looking up host addresses;
7266 that is under the control of the system
7267 .i gethostbyname (3)
7269 .ip HostStatusDirectory=\fIpath\fP
7271 The location of the long term host status information.
7273 information about the status of hosts
7274 (e.g., host down or not accepting connections)
7275 will be shared between all
7278 normally, this information is only held within a single queue run.
7279 This option requires a connection cache of at least 1 to function.
7280 If the option begins with a leading `/',
7281 it is an absolute pathname;
7283 it is relative to the mail queue directory.
7284 A suggested value for sites desiring persistent host status is
7286 (i.e., a subdirectory of the queue directory).
7289 Ignore dots in incoming messages.
7290 This is always disabled (that is, dots are always accepted)
7291 when reading SMTP mail.
7292 .ip InputMailFilters=\fIname,name,...\fP
7293 A comma separated list of filters which determines which filters
7294 (see the "X \*- Mail Filter (Milter) Definitions" section)
7295 and the invocation sequence are contacted for incoming SMTP messages.
7296 If none are set, no filters will be contacted.
7297 .ip LDAPDefaultSpec=\fIspec\fP
7299 Sets a default map specification for LDAP maps.
7300 The value should only contain LDAP specific settings
7302 .q "-h host -p port -d bindDN" .
7303 The settings will be used for all LDAP maps
7304 unless the individual map specification overrides a setting.
7305 This option should be set before any LDAP maps are defined.
7306 .ip LogLevel=\fIn\fP
7308 Set the log level to
7317 This is intended only for use from the command line.
7323 Type of lookup to find information about local mailboxes,
7324 defaults to ``pw'' which uses
7326 Other types can be introduced by adding them to the source code,
7327 see libsm/mbdb.c for details.
7330 Use as mail submission program, i.e.,
7331 allow group writable queue files
7332 if the group is the same as that of a set-group-ID sendmail binary.
7334 .b sendmail/SECURITY
7335 in the distribution tarball.
7338 Allow fuzzy matching on the GECOS field.
7339 If this flag is set,
7340 and the usual user name lookups fail
7341 (that is, there is no alias with this name and a
7344 sequentially search the password file
7345 for a matching entry in the GECOS field.
7346 This also requires that MATCHGECOS
7347 be turned on during compilation.
7348 This option is not recommended.
7349 .ip MaxAliasRecursion=\fIN\fP
7351 The maximum depth of alias recursion (default: 10).
7352 .ip MaxDaemonChildren=\fIN\fP
7356 will refuse connections when it has more than
7358 children processing incoming mail or automatic queue runs.
7359 This does not limit the number of outgoing connections.
7362 (background) is used, then
7364 may create an almost unlimited number of children
7365 (depending on the number of transactions and the
7366 relative execution times of mail receiption and mail delivery).
7367 If the limit should be enforced, then a
7369 other than background must be used.
7370 If not set, there is no limit to the number of children --
7371 that is, the system load average controls this.
7372 .ip MaxHeadersLength=\fIN\fP
7374 The maximum length of the sum of all headers.
7375 This can be used to prevent a denial of service attack.
7376 The default is no limit.
7377 .ip MaxHopCount=\fIN\fP
7379 The maximum hop count.
7380 Messages that have been processed more than
7382 times are assumed to be in a loop and are rejected.
7384 .ip MaxMessageSize=\fIN\fP
7386 Specify the maximum message size
7387 to be advertised in the ESMTP EHLO response.
7388 Messages larger than this will be rejected.
7389 If set to a value greater than zero,
7390 that value will be listed in the SIZE response,
7391 otherwise SIZE is advertised in the ESMTP EHLO response
7392 without a parameter.
7393 .ip MaxMimeHeaderLength=\fIN[/M]\fP
7395 Sets the maximum length of certain MIME header field values to
7398 These MIME header fields are determined by being a member of
7399 class {checkMIMETextHeaders}, which currently contains only
7400 the header Content-Description.
7401 For some of these headers which take parameters,
7402 the maximum length of each parameter is set to
7406 is not specified, one half of
7410 these values are 2048 and 1024, respectively.
7411 To allow any length, a value of 0 can be specified.
7412 .ip MaxNOOPCommands=\fIN\fP
7413 Override the default of
7417 commands, see Section
7418 "Measures against Denial of Service Attacks".
7419 .ip MaxQueueChildren=\fIN\fP
7421 When set, this limits the number of concurrent queue runner processes to
7423 This helps to control the amount of system resources used when processing
7424 the queue. When there are multiple queue groups defined and the total number
7425 of queue runners for these queue groups would exceed
7427 then the queue groups will not all run concurrently. That is, some portion
7428 of the queue groups will run concurrently such that
7430 will not be exceeded, while the remaining queue groups will be run later (in
7431 round robin order). See also
7432 .i MaxRunnersPerQueue
7433 and the section \fBQueue Group Declaration\fP.
7436 does not count individual queue runners, but only sets of processes
7437 that act on a workgroup.
7438 Hence the actual number of queue runners may be lower than the limit
7440 .i MaxQueueChildren .
7441 This discrepancy can be large if some queue runners have to wait
7442 for a slow server and if short intervals are used.
7443 .ip MaxQueueRunSize=\fIN\fP
7445 The maximum number of jobs that will be processed
7446 in a single queue run.
7447 If not set, there is no limit on the size.
7448 If you have very large queues or a very short queue run interval
7449 this could be unstable.
7450 However, since the first
7452 jobs in queue directory order are run (rather than the
7454 highest priority jobs)
7455 this should be set as high as possible to avoid
7457 jobs that happen to fall late in the queue directory.
7458 Note: this option also restricts the number of entries printed by
7467 entries are printed per queue group.
7468 .ip MaxRecipientsPerMessage=\fIN\fP
7470 The maximum number of recipients that will be accepted per message
7471 in an SMTP transaction.
7472 Note: setting this too low can interfere with sending mail from
7473 MUAs that use SMTP for initial submission.
7474 If not set, there is no limit on the number of recipients per envelope.
7475 .ip MaxRunnersPerQueue=\fIN\fP
7477 This sets the default maximum number of queue runners for queue groups.
7480 queue runners will work in parallel on a queue group's messages.
7481 This is useful where the processing of a message in the queue might
7482 delay the processing of subsequent messages. Such a delay may be the result
7483 of non-erroneous situations such as a low bandwidth connection.
7484 May be overridden on a per queue group basis by setting the
7486 option; see the section \fBQueue Group Declaration\fP.
7487 The default is 1 when not set.
7491 even if I am in an alias expansion.
7492 This option is deprecated
7493 and will be removed from a future version.
7496 This option has several sub(sub)options.
7497 The names of the suboptions are separated by dots.
7498 At the first level the following options are available:
7500 .ta \w'LogLevel'u+3n
7501 LogLevel Log level for input mail filter actions, defaults to LogLevel.
7502 macros Specifies list of macro to transmit to filters.
7505 The ``macros'' option has the following suboptions
7506 which specify the list of macro to transmit to milters
7507 after a certain event occurred.
7510 connect After session connection start
7511 helo After EHLO/HELO command
7512 envfrom After MAIL From command
7513 envrcpt After RCPT To command
7514 data After DATA command.
7515 eoh After DATA command and header
7516 eom After DATA command and terminating ``.''
7518 By default the lists of macros are empty.
7521 O Milter.LogLevel=12
7522 O Milter.macros.connect=j, _, {daemon_name}
7524 .ip MinFreeBlocks=\fIN\fP
7528 blocks free on the filesystem that holds the queue files
7529 before accepting email via SMTP.
7530 If there is insufficient space
7532 gives a 452 response
7533 to the MAIL command.
7534 This invites the sender to try again later.
7535 .ip MinQueueAge=\fIage\fP
7537 Don't process any queued jobs
7538 that have been in the queue less than the indicated time interval.
7539 This is intended to allow you to get responsiveness
7540 by processing the queue fairly frequently
7541 without thrashing your system by trying jobs too often.
7542 The default units are minutes.
7544 This option is ignored for queue runs that select a subset
7546 .q \-q[!][I|R|S|Q][string]
7547 .ip MustQuoteChars=\fIs\fP
7549 Sets the list of characters that must be quoted if used in a full name
7550 that is in the phrase part of a ``phrase <address>'' syntax.
7551 The default is ``\'.''.
7552 The characters ``@,;:\e()[]'' are always added to this list.
7555 The priority of queue runners (nice(3)).
7556 This value must be greater or equal zero.
7557 .ip NoRecipientAction
7559 The action to take when you receive a message that has no valid
7560 recipient headers (To:, Cc:, Bcc:, or Apparently-To: \(em
7561 the last included for back compatibility with old
7565 to pass the message on unmodified,
7566 which violates the protocol,
7568 to add a To: header with any recipients it can find in the envelope
7569 (which might expose Bcc: recipients),
7570 .b Add-Apparently-To
7571 to add an Apparently-To: header
7572 (this is only for back-compatibility
7573 and is officially deprecated),
7574 .b Add-To-Undisclosed
7576 .q "To: undisclosed-recipients:;"
7577 to make the header legal without disclosing anything,
7580 to add an empty Bcc: header.
7583 Assume that the headers may be in old format,
7585 spaces delimit names.
7586 This actually turns on
7587 an adaptive algorithm:
7588 if any recipient address contains a comma, parenthesis,
7590 it will be assumed that commas already exist.
7591 If this flag is not on,
7592 only commas delimit names.
7593 Headers are always output with commas between the names.
7595 .ip OperatorChars=\fIcharlist\fP
7597 The list of characters that are considered to be
7599 that is, characters that delimit tokens.
7600 All operator characters are tokens by themselves;
7601 sequences of non-operator characters are also tokens.
7602 White space characters separate tokens
7603 but are not tokens themselves \(em for example,
7605 has three tokens, but
7608 If not set, OperatorChars defaults to
7609 .q \&.\|:\|@\|[\|] ;
7610 additionally, the characters
7612 are always operators.
7613 Note that OperatorChars must be set in the
7614 configuration file before any rulesets.
7615 .ip PidFile=\fIfilename\fP
7617 Filename of the pid file.
7618 (default is _PATH_SENDMAILPID).
7621 is macro-expanded before it is opened, and unlinked when
7624 .ip PostmasterCopy=\fIpostmaster\fP
7627 copies of error messages will be sent to the named
7629 Only the header of the failed message is sent.
7630 Errors resulting from messages with a negative precedence will not be sent.
7631 Since most errors are user problems,
7632 this is probably not a good idea on large sites,
7633 and arguably contains all sorts of privacy violations,
7634 but it seems to be popular with certain operating systems vendors.
7635 The address is macro expanded
7636 at the time of delivery.
7637 Defaults to no postmaster copies.
7638 .ip PrivacyOptions=\fI\|opt,opt,...\fP
7642 ``Privacy'' is really a misnomer;
7643 many of these are just a way of insisting on stricter adherence
7644 to the SMTP protocol.
7647 can be selected from:
7649 .ta \w'noactualrecipient'u+3n
7650 public Allow open access
7651 needmailhelo Insist on HELO or EHLO command before MAIL
7652 needexpnhelo Insist on HELO or EHLO command before EXPN
7653 noexpn Disallow EXPN entirely, implies noverb.
7654 needvrfyhelo Insist on HELO or EHLO command before VRFY
7655 novrfy Disallow VRFY entirely
7656 noetrn Disallow ETRN entirely
7657 noverb Disallow VERB entirely
7658 restrictmailq Restrict mailq command
7659 restrictqrun Restrict \-q command line flag
7660 restrictexpand Restrict \-bv and \-v command line flags
7661 noreceipts Don't return success DSNs\**
7662 nobodyreturn Don't return the body of a message with DSNs
7663 goaway Disallow essentially all SMTP status queries
7664 authwarnings Put X-Authentication-Warning: headers in messages
7666 noactualrecipient Don't put X-Actual-Recipient lines in DSNs
7667 which reveal the actual account that addresses map to.
7673 flag turns off support for RFC 1891
7674 (Delivery Status Notification).
7678 pseudo-flag sets all flags except
7686 If mailq is restricted,
7687 only people in the same group as the queue directory
7688 can print the queue.
7689 If queue runs are restricted,
7690 only root and the owner of the queue directory
7694 pseudo-flag instructs
7696 to drop privileges when the
7698 option is given by users who are neither root nor the TrustedUser
7699 so users cannot read private aliases, forwards, or :include: files.
7703 .q DontBlameSendmail
7704 option to prevent misleading unsafe address warnings.
7705 It also overrides the
7707 (verbose) command line option to prevent information leakage.
7708 Authentication Warnings add warnings about various conditions
7709 that may indicate attempts to spoof the mail system,
7710 such as using a non-standard queue directory.
7711 .ip ProcessTitlePrefix=\fIstring\fP
7713 Prefix the process title shown on 'ps' listings with
7717 will be macro processed.
7718 .ip QueueDirectory=\fIdir\fP
7720 The QueueDirectory option serves two purposes.
7721 First, it specifies the directory or set of directories that comprise
7722 the default queue group.
7723 Second, it specifies the directory D which is the ancestor of all queue
7724 directories, and which sendmail uses as its current working directory.
7725 When sendmail dumps core, it leaves its core files in D.
7726 There are two cases.
7727 If \fIdir\fR ends with an asterisk (eg, \fI/var/spool/mqueue/qd*\fR),
7728 then all of the directories or symbolic links to directories
7729 beginning with `qd' in
7730 .i /var/spool/mqueue
7731 will be used as queue directories of the default queue group,
7733 .i /var/spool/mqueue
7734 will be used as the working directory D.
7736 \fIdir\fR must name a directory (usually \fI/var/spool/mqueue\fR):
7737 the default queue group consists of the single queue directory \fIdir\fR,
7738 and the working directory D is set to \fIdir\fR.
7739 To define additional groups of queue directories,
7740 use the configuration file `Q' command.
7741 Do not change the queue directory structure
7742 while sendmail is running.
7743 .ip QueueFactor=\fIfactor\fP
7747 as the multiplier in the map function
7748 to decide when to just queue up jobs rather than run them.
7749 This value is divided by the difference between the current load average
7750 and the load average limit
7754 to determine the maximum message priority
7757 .ip QueueLA=\fILA\fP
7759 When the system load average exceeds
7765 option divided by the difference in the current load average and the
7768 is less than the priority of the message,
7770 (i.e., don't try to send them).
7771 Defaults to 8 multiplied by
7772 the number of processors online on the system
7773 (if that can be determined).
7774 .ip QueueFileMode=\fImode\fP
7776 Default permissions for queue files (octal).
7777 If not set, sendmail uses 0600 unless its real
7778 and effective uid are different in which case it uses 0644.
7779 .ip QueueSortOrder=\fIalgorithm\fP
7783 used for sorting the queue.
7784 Only the first character of the value is used.
7787 (to order by the name of the first host name of the first recipient),
7789 (to order by the name of the queue file name),
7791 (to order by the submission/creation time),
7793 (to order randomly),
7795 (to order by the modification time of the qf file (older entries first)),
7800 (to order by message priority).
7801 Host ordering makes better use of the connection cache,
7802 but may tend to process low priority messages
7803 that go to a single host
7804 over high priority messages that go to several hosts;
7805 it probably shouldn't be used on slow network links.
7806 Filename and modification time ordering saves the overhead of
7807 reading all of the queued items
7808 before starting the queue run.
7809 Creation (submission) time ordering is almost always a bad idea,
7810 since it allows large, bulk mail to go out
7811 before smaller, personal mail,
7812 but may have applicability on some hosts with very fast connections.
7813 Random is useful if several queue runners are started by hand
7814 which try to drain the same queue since odds are they will be working
7815 on different parts of the queue at the same time.
7816 Priority ordering is the default.
7817 .ip QueueTimeout=\fItimeout\fP
7820 .q Timeout.queuereturn .
7821 Use that form instead of the
7826 Name of file containing random data or the name of the UNIX socket
7828 A (required) prefix "egd:" or "file:" specifies the type.
7829 STARTTLS requires this filename if the compile flag HASURANDOMDEV is not set
7830 (see sendmail/README).
7831 .ip ResolverOptions=\fIoptions\fP
7833 Set resolver options.
7834 Values can be set using
7860 can be specified to turn off matching against MX records
7861 when doing name canonifications.
7863 .q WorkAroundBrokenAAAA
7868 can be specified to work around some broken nameservers
7869 which return SERVFAIL (a temporary failure) on T_AAAA (IPv6) lookups.
7870 Notice: it might be necessary to apply the same (or similar) options to
7873 .ip RequiresDirfsync
7875 This option can be used to override the compile time flag
7876 .b REQUIRES_DIR_FSYNC
7877 at runtime by setting it to
7879 If the compile time flag is not set, the option is ignored.
7880 The flag turns on support for file systems that require to call
7882 for a directory if the meta-data in it has been changed.
7883 This should be turned on at least for older versions of ReiserFS;
7884 it is enabled by default for Linux.
7885 According to some information this flag is not needed
7886 anymore for kernel 2.4.16 and newer.
7889 If this option is set, a
7890 .q Return-Receipt-To:
7891 header causes the request of a DSN, which is sent to
7892 the envelope sender as required by RFC 1891,
7893 not to the address given in the header.
7894 .ip RunAsUser=\fIuser\fP
7898 parameter may be a user name
7901 or a numeric user id;
7902 either form can have
7905 (where group can be numeric or symbolic).
7906 If set to a non-zero (non-root) value,
7908 will change to this user id shortly after startup\**.
7910 \**When running as a daemon,
7911 it changes to this user after accepting a connection
7912 but before reading any
7916 This avoids a certain class of security problems.
7917 However, this means that all
7921 files must be readable by the indicated
7923 and all files to be written must be writable by
7925 Also, all file and program deliveries will be marked unsafe
7927 .b DontBlameSendmail=NonRootSafeAddr
7929 in which case the delivery will be done as
7931 It is also incompatible with the
7932 .b SafeFileEnvironment
7934 In other words, it may not actually add much to security on an average system,
7935 and may in fact detract from security
7936 (because other file permissions must be loosened).
7937 However, it should be useful on firewalls and other
7938 places where users don't have accounts and the aliases file is
7940 .ip RecipientFactor=\fIfact\fP
7944 is added to the priority (thus
7946 the priority of the job)
7948 i.e., this value penalizes jobs with large numbers of recipients.
7950 .ip RefuseLA=\fILA\fP
7952 When the system load average exceeds
7954 refuse incoming SMTP connections.
7955 Defaults to 12 multiplied by
7956 the number of processors online on the system
7957 (if that can be determined).
7958 .ip RejectLogInterval=\fItimeout\fP
7960 Log interval when refusing connections for this long
7962 .ip RetryFactor=\fIfact\fP
7966 is added to the priority
7967 every time a job is processed.
7969 each time a job is processed,
7970 its priority will be decreased by the indicated value.
7971 In most environments this should be positive,
7972 since hosts that are down are all too often down for a long time.
7974 .ip SafeFileEnvironment=\fIdir\fP
7976 If this option is set,
7980 call into the indicated
7982 before doing any file writes.
7983 If the file name specified by the user begins with
7985 that partial path name will be stripped off before writing,
7987 if the SafeFileEnvironment variable is set to
7993 actually indicate the same file.
7994 Additionally, if this option is set,
7996 refuses to deliver to symbolic links.
8002 lines at the front of headers.
8003 Normally they are assumed redundant
8007 If set, send error messages in MIME format
8008 (see RFC 2045 and RFC 1344 for details).
8011 will not return the DSN keyword in response to an EHLO
8012 and will not do Delivery Status Notification processing as described in
8016 File containing the certificate of the server, i.e., this certificate
8017 is used when sendmail acts as server
8018 (used for STARTTLS).
8021 File containing the private key belonging to the server certificate
8022 (used for STARTTLS).
8023 .ip ServiceSwitchFile=\fIfilename\fP
8025 If your host operating system has a service switch abstraction
8026 (e.g., /etc/nsswitch.conf on Solaris
8027 or /etc/svc.conf on Ultrix and DEC OSF/1)
8028 that service will be consulted and this option is ignored.
8029 Otherwise, this is the name of a file
8030 that provides the list of methods used to implement particular services.
8031 The syntax is a series of lines,
8032 each of which is a sequence of words.
8033 The first word is the service name,
8034 and following words are service types.
8037 consults directly are
8041 Service types can be
8047 (with the caveat that the appropriate support
8049 before the service can be referenced).
8050 If ServiceSwitchFile is not specified, it defaults to
8051 /etc/mail/service.switch.
8052 If that file does not exist, the default switch is:
8058 .q /etc/mail/service.switch .
8061 Strip input to seven bits for compatibility with old systems.
8062 This shouldn't be necessary.
8065 Key to use for shared memory segment;
8066 if not set (or 0), shared memory will not be used.
8070 can select a key itself provided that also
8071 .b SharedMemoryKeyFile
8073 Requires support for shared memory to be compiled into
8075 If this option is set,
8077 can share some data between different instances.
8078 For example, the number of entries in a queue directory
8079 or the available space in a file system.
8080 This allows for more efficient program execution, since only
8081 one process needs to update the data instead of each individual
8082 process gathering the data each time it is required.
8083 .ip SharedMemoryKeyFile
8089 then the automatically selected shared memory key will be stored
8090 in the specified file.
8091 .ip SingleLineFromHeader
8093 If set, From: lines that have embedded newlines are unwrapped
8095 This is to get around a botch in Lotus Notes
8096 that apparently cannot understand legally wrapped RFC 822 headers.
8097 .ip SingleThreadDelivery
8099 If set, a client machine will never try to open two SMTP connections
8100 to a single server machine at the same time,
8101 even in different processes.
8104 is already talking to some host a new
8106 will not open another connection.
8107 This property is of mixed value;
8108 although this reduces the load on the other machine,
8109 it can cause mail to be delayed
8110 (for example, if one
8112 is delivering a huge message, other
8114 won't be able to send even small messages).
8115 Also, it requires another file descriptor
8117 per connection, so you may have to reduce the
8118 .b ConnectionCacheSize
8119 option to avoid running out of per-process file descriptors.
8121 .b HostStatusDirectory
8123 .ip SmtpGreetingMessage=\fImessage\fP
8125 The message printed when the SMTP server starts up.
8127 .q "$j Sendmail $v ready at $b".
8129 If set, issue temporary errors (4xy) instead of permanent errors (5xy).
8130 This can be useful during testing of a new configuration to avoid
8131 erroneous bouncing of mails.
8132 .ip StatusFile=\fIfile\fP
8134 Log summary statistics in the named
8136 If no file name is specified, "statistics" is used.
8138 no summary statistics are saved.
8139 This file does not grow in size.
8140 It can be printed using the
8145 This option can be set to True, False, Interactive, or PostMilter.
8148 will be super-safe when running things,
8149 i.e., always instantiate the queue file,
8150 even if you are going to attempt immediate delivery.
8152 always instantiates the queue file
8153 before returning control to the client
8154 under any circumstances.
8158 The Interactive value has been introduced in 8.12 and can
8159 be used together with
8161 It skips some synchronization calls which are effectively
8162 doubled in the code execution path for this mode.
8163 If set to PostMilter,
8165 defers synchronizing the queue file until any milters have
8166 signaled acceptance of the message.
8167 PostMilter is useful only when
8169 is running as an SMTP server; in all other situations it
8170 acts the same as True.
8173 List of options for SMTP STARTTLS for the server
8174 consisting of single characters
8175 with intervening white space or commas.
8176 The flag ``V'' disables client verification, and hence
8177 it is not possible to use a client certificate for relaying.
8178 Currently there are no other flags available.
8179 .ip TempFileMode=\fImode\fP
8181 The file mode for transcript files, files to which
8183 delivers directly, files in the
8184 .b HostStatusDirectory ,
8187 It is interpreted in octal by default.
8189 .ip Timeout.\fItype\fP=\|\fItimeout\fP
8190 [r; subsumes old T option as well]
8192 For more information,
8196 .ip TimeZoneSpec=\fItzinfo\fP
8198 Set the local time zone info to
8202 Actually, if this is not set,
8203 the TZ environment variable is cleared (so the system default is used);
8204 if set but null, the user's TZ variable is used,
8205 and if set and non-null the TZ variable is set to this value.
8206 .ip TrustedUser=\fIuser\fP
8210 parameter may be a user name
8213 or a numeric user id.
8214 Trusted user for file ownership and starting the daemon. If set, generated
8215 alias databases and the control socket (if configured) will automatically
8216 be owned by this user.
8219 If this system is the
8221 (that is, lowest preference)
8222 MX for a given host,
8223 its configuration rules should normally detect this situation
8224 and treat that condition specially
8225 by forwarding the mail to a UUCP feed,
8226 treating it as local,
8228 However, in some cases (such as Internet firewalls)
8229 you may want to try to connect directly to that host
8230 as though it had no MX records at all.
8231 Setting this option causes
8234 The downside is that errors in your configuration
8235 are likely to be diagnosed as
8238 .q "message timed out"
8239 instead of something more meaningful.
8240 This option is disrecommended.
8241 .ip UnixFromLine=\fIfromline\fP
8243 Defines the format used when
8245 must add a UNIX-style From_ line
8246 (that is, a line beginning
8247 .q From<space>user ).
8250 Don't change this unless your system uses a different UNIX mailbox format
8252 .ip UnsafeGroupWrites
8255 :include: and .forward files that are group writable are considered
8258 they cannot reference programs or write directly to files.
8259 World writable :include: and .forward files
8262 .b DontBlameSendmail
8263 instead; this option is deprecated.
8268 header, send error messages to the addresses listed there.
8269 They normally go to the envelope sender.
8270 Use of this option causes
8272 to violate RFC 1123.
8273 This option is disrecommended and deprecated.
8274 .ip UserDatabaseSpec=\fIudbspec\fP
8276 The user database specification.
8279 Run in verbose mode.
8290 so that all mail is delivered completely
8292 so that you can see the entire delivery process.
8297 be set in the configuration file;
8298 it is intended for command line use only.
8299 Note that the use of option
8301 can cause authentication information to leak, if you use a
8302 sendmail client to authenticate to a server.
8303 If the authentication mechanism uses plain text passwords
8304 (as with LOGIN or PLAIN),
8305 then the password could be compromised.
8306 To avoid this, do not install sendmail set-user-ID root,
8309 SMTP command with a suitable
8312 .ip XscriptFileBufferSize=\fIthreshold\fP
8317 before a memory-based
8318 queue transcript file
8320 The default is 4096 bytes.
8322 All options can be specified on the command line using the
8326 to relinquish its set-user-ID permissions.
8327 The options that will not cause this are
8331 CheckpointInterval [C],
8338 OldStyleHeaders [o],
8349 SingleLineFromHeader,
8352 Actually, PrivacyOptions [p] given on the command line
8353 are added to those already specified in the
8355 file, i.e., they can't be reset.
8356 Also, M (define macro) when defining the r or s macros
8359 .sh 2 "P \*- Precedence Definitions"
8363 field may be defined using the
8366 The syntax of this field is:
8368 \fBP\fP\fIname\fP\fB=\fP\fInum\fP
8375 the message class is set to
8377 Higher numbers mean higher precedence.
8378 Numbers less than zero
8379 have the special property
8380 that if an error occurs during processing
8381 the body of the message will not be returned;
8382 this is expected to be used for
8384 mail such as through mailing lists.
8385 The default precedence is zero.
8387 our list of precedences is:
8390 Pspecial-delivery=100
8395 People writing mailing list exploders
8396 are encouraged to use
8397 .q "Precedence: list" .
8400 (which discarded all error returns for negative precedences)
8401 didn't recognize this name, giving it a default precedence of zero.
8402 This allows list maintainers to see error returns
8403 on both old and new versions of
8405 .sh 2 "V \*- Configuration Version Level"
8407 To provide compatibility with old configuration files,
8410 line has been added to define some very basic semantics
8411 of the configuration file.
8412 These are not intended to be long term supports;
8413 rather, they describe compatibility features
8414 which will probably be removed in future releases.
8420 to do with the version
8425 version 10 config files
8426 (specifically, 8.10)
8427 used version level 9 configurations.
8430 configuration files are defined as version level one.
8431 Version level two files make the following changes:
8433 Host name canonification ($[ ... $])
8434 appends a dot if the name is recognized;
8435 this gives the config file a way of finding out if anything matched.
8436 (Actually, this just initializes the
8440 flag \*- you can reset it to anything you prefer
8441 by declaring the map explicitly.)
8443 Default host name extension is consistent throughout processing;
8444 version level one configurations turned off domain extension
8445 (that is, adding the local domain name)
8446 during certain points in processing.
8447 Version level two configurations are expected to include a trailing dot
8448 to indicate that the name is already canonical.
8450 Local names that are not aliases
8451 are passed through a new distinguished ruleset five;
8452 this can be used to append a local relay.
8453 This behavior can be prevented by resolving the local name
8454 with an initial `@'.
8455 That is, something that resolves to a local mailer and a user name of
8457 will be passed through ruleset five,
8460 will have the `@' stripped,
8461 will not be passed through ruleset five,
8462 but will otherwise be treated the same as the prior example.
8463 The expectation is that this might be used to implement a policy
8466 was handled by a central hub,
8469 was delivered directly.
8471 Version level three files
8472 allow # initiated comments on all lines.
8473 Exceptions are backslash escaped # marks
8476 Version level four configurations
8477 are completely equivalent to level three
8478 for historical reasons.
8480 Version level five configuration files
8481 change the default definition of
8483 to be just the first component of the hostname.
8485 Version level six configuration files
8486 change many of the local processing options
8487 (such as aliasing and matching the beginning of the address for
8490 this allows fine-grained control over the special local processing.
8491 Level six configuration files may also use long option names.
8494 option (to allow colons in the local-part of addresses)
8497 for lower numbered configuration files;
8498 the configuration file requires some additional intelligence
8499 to properly handle the RFC 822 group construct.
8501 Version level seven configuration files
8502 used new option names to replace old macros
8506 .b SmtpGreetingMessage ,
8514 Also, prior to version seven,
8517 flag (use 250 instead of 252 return value for
8522 Version level eight configuration files allow
8524 on the left hand side of ruleset lines.
8526 Version level nine configuration files allow
8527 parentheses in rulesets, i.e. they are not treated
8528 as comments and hence removed.
8530 Version level ten configuration files allow
8531 queue group definitions.
8535 line may have an optional
8538 to indicate that this configuration file uses modifications
8539 specific to a particular vendor\**.
8541 \**And of course, vendors are encouraged to add themselves
8542 to the list of recognized vendors by editing the routine
8546 Please send e-mail to sendmail@Sendmail.ORG
8547 to register your vendor dialect.
8551 to emphasize that this configuration file
8552 uses the Berkeley dialect of
8554 .sh 2 "K \*- Key File Declaration"
8556 Special maps can be defined using the line:
8558 Kmapname mapclass arguments
8562 is the handle by which this map is referenced in the rewriting rules.
8565 is the name of a type of map;
8566 these are compiled in to
8570 are interpreted depending on the class;
8572 there would be a single argument naming the file containing the map.
8574 Maps are referenced using the syntax:
8576 $( \fImap\fP \fIkey\fP $@ \fIarguments\fP $: \fIdefault\fP $)
8578 where either or both of the
8582 portion may be omitted.
8585 may appear more than once.
8590 are passed to the appropriate mapping function.
8591 If it returns a value, it replaces the input.
8592 If it does not return a value and the
8597 Otherwise, the input is unchanged.
8601 are passed to the map for arbitrary use.
8602 Most map classes can interpolate these arguments
8603 into their values using the syntax
8608 to indicate the corresponding
8612 indicates the database key.
8613 For example, the rule
8616 R$\- ! $+ $: $(uucp $1 $@ $2 $: $2 @ $1 . UUCP $)
8618 Looks up the UUCP name in a (user defined) UUCP map;
8619 if not found it turns it into
8622 The database might contain records like:
8624 decvax %1@%0.DEC.COM
8625 research %1@%0.ATT.COM
8629 clauses never do this mapping.
8631 The built-in map with both name and class
8633 is the host name canonicalization lookup.
8637 $(host \fIhostname\fP$)
8644 There are many defined classes.
8646 Database lookups using the ndbm(3) library.
8648 must be compiled with
8652 Database lookups using the btree interface to the Berkeley DB
8655 must be compiled with
8659 Database lookups using the hash interface to the Berkeley DB
8662 must be compiled with
8668 must be compiled with
8674 must be compiled with
8677 The argument is the name of the table to use for lookups,
8682 flags may be used to set the key and value columns respectively.
8686 must be compiled with
8690 LDAP X500 directory lookups.
8692 must be compiled with
8695 The map supports most of the standard arguments
8696 and most of the command line arguments of the
8701 if a single query matches multiple values,
8702 only the first value will be returned
8709 map flag will treat a multiple value return
8710 as if there were no matches.
8712 NeXT NetInfo lookups.
8714 must be compiled with
8719 The format of the text file is defined by the
8723 (value field number),
8730 Contributed and supported by
8731 Mark Roth, roth@uiuc.edu.
8732 For more information,
8733 consult the web site
8734 .q http://www-dev.cites.uiuc.edu/sendmail/ .
8736 nsd map for IRIX 6.5 and later.
8737 Contributed and supported by Bob Mende of SGI,
8740 Internal symbol table lookups.
8741 Used internally for aliasing.
8743 Really should be called
8745 \(em this is used to get the default lookups
8747 and is the default if no class is specified for alias files.
8749 Looks up users using
8753 flag can be used to specify the name of the field to return
8754 (although this is normally used only to check the existence
8757 Canonifies host domain names.
8758 Given a host name it calls the name server
8759 to find the canonical name for that host.
8761 Returns the best MX record for a host name given as the key.
8762 The current machine is always preferred \*-
8763 that is, if the current machine is one of the hosts listed as a
8764 lowest-preference MX record, then it will be guaranteed to be returned.
8765 This can be used to find out if this machine is the target for an MX record,
8766 and mail can be accepted on that basis.
8769 flag is given, then all MX names are returned,
8770 separated by the given delimiter.
8772 This map requires the option -R to specify the DNS resource record
8773 type to lookup. The following types are supported:
8774 A, AAAA, AFSDB, CNAME, MX, NS, PTR, SRV, and TXT.
8775 A map lookup will return only one record.
8776 Hence for some types, e.g., MX records, the return value might be a random
8777 element of the list due to randomizing in the DNS resolver.
8779 The arguments on the `K' line are a list of maps;
8780 the resulting map searches the argument maps in order
8781 until it finds a match for the indicated key.
8782 For example, if the key definition is:
8786 Kseqmap sequence map1 map2
8788 then a lookup against
8790 first does a lookup in map1.
8791 If that is found, it returns immediately.
8792 Otherwise, the same key is used for map2.
8794 the key is logged via
8796 The lookup returns the empty string.
8800 map except that the order of maps is determined by the service switch.
8801 The argument is the name of the service to be looked up;
8802 the values from the service switch are appended to the map name
8803 to create new map names.
8804 For example, consider the key definition:
8808 together with the service switch entry:
8812 This causes a query against the map
8814 to search maps named
8820 Strip double quotes (") from a name.
8821 It does not strip backslashes,
8822 and will not strip quotes if the resulting string
8823 would contain unscannable syntax
8824 (that is, basic errors like unbalanced angle brackets;
8825 more sophisticated errors such as unknown hosts are not checked).
8826 The intent is for use when trying to accept mail from systems such as
8828 that routinely quote odd syntax such as
8832 A typical usage is probably something like:
8838 R$\- $: $(dequote $1 $)
8839 R$\- $+ $: $>3 $1 $2
8841 Care must be taken to prevent unexpected results;
8844 "|someprogram < input > output"
8846 will have quotes stripped,
8847 but the result is probably not what you had in mind.
8848 Fortunately these cases are rare.
8850 The map definition on the
8852 line contains a regular expression.
8853 Any key input is compared to that expression using the
8854 POSIX regular expressions routines regcomp(), regerr(), and regexec().
8855 Refer to the documentation for those routines for more information
8856 about the regular expression matching.
8857 No rewriting of the key is done if the
8859 flag is used. Without it, the key is discarded or if
8861 if used, it is substituted by the substring matches, delimited by
8863 or the string specified with the the
8865 flag. The flags available for the map are
8870 -b basic regular expressions (default is extended)
8872 -d set the delimiter used for -s
8873 -a append string to key
8874 -m match only, do not replace/discard value
8875 -D perform no lookup in deferred delivery mode.
8879 flag can include an optional parameter which can be used
8880 to select the substrings in the result of the lookup. For example,
8889 If the pattern contains spaces, they must be replaced
8890 with the blank substitution character, unless it is
8893 The arguments on the
8895 line are the pathname to a program and any initial parameters to be passed.
8896 When the map is called,
8897 the key is added to the initial parameters
8898 and the program is invoked
8899 as the default user/group id.
8900 The first line of standard output is returned as the value of the lookup.
8901 This has many potential security problems,
8902 and has terrible performance;
8903 it should be used only when absolutely necessary.
8905 Set or clear a macro value.
8907 pass the value as the first argument in the map lookup.
8909 do not pass an argument in the map lookup.
8910 The map always returns the empty string.
8911 Example of typical usage include:
8917 # set macro ${MyMacro} to the ruleset match
8918 R$+ $: $(storage {MyMacro} $@ $1 $) $1
8919 # set macro ${MyMacro} to an empty string
8920 R$* $: $(storage {MyMacro} $@ $) $1
8921 # clear macro ${MyMacro}
8922 R$\- $: $(storage {MyMacro} $) $1
8925 Perform simple arithmetic operations.
8926 The operation is given as key, currently
8928 |, & (bitwise OR, AND),
8929 l (for less than), =,
8930 and r (for random) are supported.
8931 The two operands are given as arguments.
8932 The lookup returns the result of the computation,
8937 for comparisons, integer values otherwise.
8938 The r operator returns a pseudo-random number whose value
8939 lies between the first and second operand
8940 (which requires that the first operand is smaller than the second).
8941 All options which are possible for maps are ignored.
8942 A simple example is:
8949 R$* $: $(comp l $@ $&{load_avg} $@ 7 $) $1
8950 RFALSE $# error \&...
8953 The socket map uses a simple request/reply protocol over TCP or UNIX domain
8954 sockets to query an external server.
8955 Both requests and replies are text based and encoded as netstrings,
8956 i.e., a string "hello there" becomes:
8960 Note: neither requests nor replies end with CRLF.
8962 The request consists of the database map name and the lookup key separated
8963 by a space character:
8969 The server responds with a status indicator and the result (if any):
8972 <status> ' ' <result>
8975 The status indicator specifies the result of the lookup operation itself
8976 and is one of the following upper case words:
8979 OK the key was found, result contains the looked up value
8980 NOTFOUND the key was not found, the result is empty
8981 TEMP a temporary failure occured
8982 TIMEOUT a timeout occured on the server side
8983 PERM a permanent failure occured
8986 In case of errors (status TEMP, TIMEOUT or PERM) the result field may
8987 contain an explanatory message.
8988 However, the explanatory message is not used any further by
8993 31:OK resolved.address@example.com,
8997 56:OK error:550 5.7.1 User does not accept mail from sender,
9000 in case of successful lookups, or:
9005 in case the key was not found, or:
9007 55:TEMP this text explains that we had a temporary failure,
9010 in case of a temporary map lookup failure.
9012 The socket map uses the same syntax as milters
9013 (see Section "X \*- Mail Filter (Milter) Definitions")
9014 to specify the remote endpoint, e.g.,
9016 Ksocket mySocketMap inet:12345@127.0.0.1
9019 If multiple socket maps define the same remote endpoint, they will share
9020 a single connection to this endpoint.
9022 Most of these accept as arguments the same optional flags
9024 (or a mapname for NIS;
9025 the filename is the root of the database path,
9028 or some other extension appropriate for the database type
9029 will be added to get the actual database name).
9032 Indicates that this map is optional \*- that is,
9033 if it cannot be opened,
9034 no error is produced,
9037 will behave as if the map existed but was empty.
9045 uses an adaptive algorithm to decide whether or not to look for null bytes
9047 It starts by trying both;
9048 if it finds any key with a null byte it never tries again without a null byte
9052 is specified it never tries without a null byte and
9055 is specified it never tries with a null byte.
9057 these can speed matches but are never necessary.
9064 will never try any matches at all \(em
9065 that is, everything will appear to fail.
9069 on successful matches.
9070 For example, the default
9072 map appends a dot on successful matches.
9076 on temporary failures.
9079 would be appended if a DNS lookup returned
9081 or an NIS lookup could not locate a server.
9086 Do not fold upper to lower case before looking up the key.
9088 Match only (without replacing the value).
9089 If you only care about the existence of a key and not the value
9090 (as you might when searching the NIS map
9093 this flag prevents the map from substituting the value.
9095 The \-a argument is still appended on a match,
9096 and the default is still taken if the match fails.
9097 .ip "\-k\fIkeycol\fP"
9098 The key column name (for NIS+) or number
9100 For LDAP maps this is an LDAP filter string
9101 in which %s is replaced with the literal contents of the lookup key
9102 and %0 is replaced with the LDAP escaped contents of the lookup key
9103 according to RFC 2254.
9106 is used, then %1 through %9 are replaced with the LDAP escaped contents
9107 of the arguments specified in the map lookup.
9108 .ip "\-v\fIvalcol\fP"
9109 The value column name (for NIS+) or number
9111 For LDAP maps this is the name of one or more
9112 attributes to be returned;
9113 multiple attributes can be separated by commas.
9114 If not specified, all attributes found in the match
9116 The attributes listed can also include a type and one or more
9117 objectClass values for matching as described in the LDAP section.
9118 .ip "\-z\fIdelim\fP"
9119 The column delimiter (for text lookups).
9120 It can be a single character or one of the special strings
9124 to indicate newline or tab respectively.
9125 If omitted entirely,
9126 the column separator is any sequence of white space.
9127 For LDAP maps this is the separator character
9128 to combine multiple values
9129 into a single return string.
9131 the LDAP lookup will only return the first match found.
9132 For DNS maps this is the separator character at which
9133 the result of a query is cut off if is too long.
9135 Normally, when a map attempts to do a lookup
9136 and the server fails
9139 couldn't contact any name server;
9142 the same as an entry not being found in the map),
9143 the message being processed is queued for future processing.
9146 flag turns off this behavior,
9147 letting the temporary failure (server down)
9148 act as though it were a permanent failure (entry not found).
9149 It is particularly useful for DNS lookups,
9150 where someone else's misconfigured name server can cause problems
9152 However, care must be taken to ensure that you don't bounce mail
9153 that would be resolved correctly if you tried again.
9154 A common strategy is to forward such mail
9155 to another, possibly better connected, mail server.
9157 Perform no lookup in deferred delivery mode.
9158 This flag is set by default for the
9161 .ip "\-S\fIspacesub\fP
9162 The character to use to replace space characters
9163 after a successful map lookup (esp. useful for regex
9165 .ip "\-s\fIspacesub\fP
9166 For the dequote map only,
9167 the character to use to replace space characters
9168 after a successful dequote.
9170 Don't dequote the key before lookup.
9172 For the syslog map only, it specifies the level
9173 to use for the syslog call.
9175 When rebuilding an alias file,
9178 flag causes duplicate entries in the text version
9180 For example, two entries:
9185 would be treated as though it were the single entry
9187 list: user1, user2, user3
9189 in the presence of the
9193 Some additional flags are available for the host and dns maps:
9195 delay: specify the resolver's retransmission time interval (in seconds).
9197 retry: specify the number of times to retransmit a resolver query.
9199 The dns map has another flag:
9201 basedomain: specify a domain that is always appended to queries.
9203 The following additional flags are present in the ldap map only:
9205 Do not auto chase referrals. sendmail must be compiled with
9206 .b \-DLDAP_REFERRALS
9209 Retrieve attribute names only.
9211 Retrieve both attributes name and value(s),
9214 .ip "\-r\fIderef\fP"
9215 Set the alias dereference option to one of never, always, search, or find.
9216 .ip "\-s\fIscope\fP"
9217 Set search scope to one of base, one (one level), or sub (subtree).
9219 LDAP server hostname.
9220 Some LDAP libraries allow you to specify multiple, space-separated hosts for
9222 In addition, each of the hosts listed can be followed by a colon and a port
9223 number to override the default LDAP port.
9226 .ip "\-H \fILDAPURI\fP"
9227 Use the specified LDAP URI instead of specifying the hostname and port
9228 separately with the the
9232 options shown above.
9235 -h server.example.com -p 389 -b dc=example,dc=com
9239 -H ldap://server.example.com:389 -b dc=example,dc=com
9241 If the LDAP library supports it,
9242 the LDAP URI format however can also request LDAP over SSL by using
9248 O LDAPDefaultSpec=-H ldaps://ldap.example.com -b dc=example,dc=com
9250 Similarly, if the LDAP library supports it,
9251 It can also be used to specify a UNIX domain socket using
9254 O LDAPDefaultSpec=-H ldapi://socketfile -b dc=example,dc=com
9258 .ip "\-l\fItimelimit\fP"
9259 Time limit for LDAP queries.
9260 .ip "\-Z\fIsizelimit\fP"
9261 Size (number of matches) limit for LDAP or DNS queries.
9262 .ip "\-d\fIdistinguished_name\fP"
9263 The distinguished name to use to login to the LDAP server.
9264 .ip "\-M\fImethod\fP"
9265 The method to authenticate to the LDAP server.
9268 .b LDAP_AUTH_SIMPLE ,
9270 .b LDAP_AUTH_KRBV4 .
9271 .ip "\-P\fIpasswordfile\fP"
9272 The file containing the secret key for the
9274 authentication method
9275 or the name of the Kerberos ticket file for
9276 .b LDAP_AUTH_KRBV4 .
9278 Force LDAP searches to only succeed if a single match is found.
9279 If multiple values are found,
9280 the search is treated as if no match was found.
9281 .ip "\-w\fIversion\fP"
9282 Set the LDAP API/protocol version to use.
9283 The default depends on the LDAP client libraries in use.
9288 to use LDAPv3 when communicating with the LDAP server.
9290 Treat the LDAP search key as multi-argument and
9291 replace %1 through %9 in the key with
9292 the LDAP escaped contents of the lookup arguments specified in the map lookup.
9296 map appends the strings
9300 to the given filename;
9307 For example, the map specification
9309 Kuucp dbm \-o \-N /etc/mail/uucpmap
9311 specifies an optional map named
9315 it always has null bytes at the end of every string,
9316 and the data is located in
9317 /etc/mail/uucpmap.{dir,pag}.
9321 can be used to build any of the three database-oriented maps.
9322 It takes the following flags:
9324 Do not fold upper to lower case in the map.
9326 Include null bytes in keys.
9328 Append to an existing (old) file.
9330 Allow replacement of existing keys;
9331 normally, re-inserting an existing key is an error.
9333 Print what is happening.
9337 daemon does not have to be restarted to read the new maps
9338 as long as you change them in place;
9339 file locking is used so that the maps won't be read
9340 while they are being updated.
9342 New classes can be added in the routine
9346 .sh 2 "Q \*- Queue Group Declaration"
9348 In addition to the option
9350 queue groups can be declared that define a (group of) queue directories
9351 under a common name.
9352 The syntax is as follows:
9362 is the symbolic name of the queue group under which
9363 it can be referenced in various places
9366 pairs define attributes of the queue group.
9367 The name must only consist of alphanumeric characters.
9370 Flags for this queue group.
9372 The nice(2) increment for the queue group.
9373 This value must be greater or equal zero.
9375 The time between two queue runs.
9377 The queue directory of the group (required).
9379 The number of parallel runners processing the queue.
9382 must be set if this value is greater than one.
9384 The maximum number of jobs (messages delivered) per queue run.
9386 The maximum number of recipients per envelope.
9387 Envelopes with more than this number of recipients will be split
9388 into multiple envelopes in the same queue directory.
9389 The default value 0 means no limit.
9391 Only the first character of the field name is checked.
9393 By default, a queue group named
9395 is defined that uses the value of the
9398 Notice: all paths that are used for queue groups must
9399 be subdirectories of
9401 Since they can be symbolic links, this isn't a real restriction,
9404 uses a wildcard, then the directory one level up is considered
9405 the ``base'' directory which all other queue directories must share.
9406 Please make sure that the queue directories do not overlap,
9407 e.g., do not specify
9409 O QueueDirectory=/var/spool/mqueue/*
9410 Qone, P=/var/spool/mqueue/dir1
9411 Qtwo, P=/var/spool/mqueue/dir2
9413 because this also includes
9417 in the default queue group.
9420 O QueueDirectory=/var/spool/mqueue/main*
9421 Qone, P=/var/spool/mqueue/dir
9422 Qtwo, P=/var/spool/mqueue/other*
9424 is a valid queue group specification.
9426 Options listed in the ``Flags'' field can be used to modify
9427 the behavior of a queue group.
9428 The ``f'' flag must be set if multiple queue runners are
9429 supposed to work on the entries in a queue group.
9432 will work on the entries strictly sequentially.
9434 The ``Interval'' field sets the time between queue runs.
9435 If no queue group specific interval is set, then the parameter of the
9437 option from the command line is used.
9439 To control the overall number of concurrently active queue runners
9443 This limits the number of processes used for running the queues to
9444 .b MaxQueueChildren ,
9445 though at any one time fewer processes may be active
9446 as a result of queue options, completed queue runs, system load, etc.
9448 The maximum number of queue runners for an individual queue group can be
9452 If set to 0, entries in the queue will not be processed, which
9453 is useful to ``quarantine'' queue files.
9454 The number of runners per queue group may also be set with the option
9455 .b MaxRunnersPerQueue ,
9456 which applies to queue groups that have no individual limit.
9457 That is, the default value for
9460 .b MaxRunnersPerQueue
9461 if set, otherwise 1.
9463 The field Jobs describes the maximum number of jobs
9464 (messages delivered) per queue run, which is the queue group specific
9466 .b MaxQueueRunSize .
9468 Notice: queue groups should be declared after all queue related options
9469 have been set because queue groups take their defaults from those options.
9470 If an option is set after a queue group declaration, the values of
9471 options in the queue group are set to the defaults of
9473 unless explicitly set in the declaration.
9475 Each envelope is assigned to a queue group based on the algorithm
9476 described in section
9477 ``Queue Groups and Queue Directories''.
9478 .sh 2 "X \*- Mail Filter (Milter) Definitions"
9482 Mail Filter API (Milter) is designed to allow third-party programs access
9483 to mail messages as they are being processed in order to filter
9484 meta-information and content.
9485 They are declared in the configuration file as:
9495 is the name of the filter
9496 (used internally only)
9499 pairs define attributes of the filter.
9500 Also see the documentation for the
9502 option for more information.
9507 Socket The socket specification
9508 Flags Special flags for this filter
9509 Timeouts Timeouts for this filter
9511 Only the first character of the field name is checked
9512 (it's case-sensitive).
9514 The socket specification is one of the following forms:
9537 The first two describe an IPv4 or IPv6 socket listening on a certain
9542 The final form describes a named socket on the filesystem at the given
9545 The following flags may be set in the filter description.
9548 Reject connection if filter unavailable.
9550 Temporary fail connection if filter unavailable.
9552 If neither F=R nor F=T is specified, the message is passed through
9554 in case of filter errors as if the failing filters were not present.
9556 The timeouts can be set using the four fields inside of the
9561 Timeout for connecting to a filter.
9562 If set to 0, the system's
9564 timeout will be used.
9566 Timeout for sending information from the MTA to a filter.
9568 Timeout for reading reply from the filter.
9570 Overall timeout between sending end-of-message to filter and waiting for
9571 the final acknowledgment.
9573 Note the separator between each timeout field is a
9575 The default values (if not set) are:
9576 .b T=C:5m;S:10s;R:10s;E:5m
9585 Xfilter1, S=local:/var/run/f1.sock, F=R
9586 Xfilter2, S=inet6:999@localhost, F=T, T=S:1s;R:1s;E:5m
9587 Xfilter3, S=inet:3333@localhost, T=C:2m
9589 .sh 2 "The User Database"
9591 The user database is deprecated in favor of ``virtusertable''
9592 and ``genericstable'' as explained in the file
9594 If you have a version of
9596 with the user database package
9598 the handling of sender and recipient addresses
9601 The location of this database is controlled with the
9604 .sh 3 "Structure of the user database"
9606 The database is a sorted (BTree-based) structure.
9607 User records are stored with the key:
9609 \fIuser-name\fP\fB:\fP\fIfield-name\fP
9611 The sorted database format ensures that user records are clustered together.
9612 Meta-information is always stored with a leading colon.
9614 Field names define both the syntax and semantics of the value.
9615 Defined fields include:
9618 The delivery address for this user.
9619 There may be multiple values of this record.
9621 mailing lists will have one
9623 record for each user on the list.
9625 The outgoing mailname for this user.
9626 For each outgoing name,
9627 there should be an appropriate
9629 record for that name to allow return mail.
9631 .i :default:mailname .
9633 Changes any mail sent to this address to have the indicated envelope sender.
9634 This is intended for mailing lists,
9635 and will normally be the name of an appropriate -request address.
9636 It is very similar to the owner-\c
9638 syntax in the alias file.
9640 The full name of the user.
9642 The office address for this user.
9644 The office phone number for this user.
9646 The office FAX number for this user.
9648 The home address for this user.
9650 The home phone number for this user.
9652 The home FAX number for this user.
9654 A (short) description of the project this person is affiliated with.
9655 In the University this is often just the name of their graduate advisor.
9657 A pointer to a file from which plan information can be gathered.
9660 only a few of these fields are actually being used by
9667 program that uses the other fields is planned.
9668 .sh 3 "User database semantics"
9670 When the rewriting rules submit an address to the local mailer,
9671 the user name is passed through the alias file.
9672 If no alias is found (or if the alias points back to the same address),
9676 is then used as a key in the user database.
9677 If no match occurs (or if the maildrop points at the same address),
9678 forwarding is tried.
9680 If the first token of the user name returned by ruleset 0
9683 sign, the user database lookup is skipped.
9684 The intent is that the user database will act as a set of defaults
9685 for a cluster (in our case, the Computer Science Division);
9686 mail sent to a specific machine should ignore these defaults.
9689 the name of the sending user is looked up in the database.
9693 the value of that record is used as their outgoing name.
9694 For example, I might have a record:
9696 eric:mailname Eric.Allman@CS.Berkeley.EDU
9698 This would cause my outgoing mail to be sent as Eric.Allman.
9702 is found for the user,
9703 but no corresponding
9707 .q :default:mailname
9709 If present, this is the name of a host to override the local host.
9710 For example, in our case we would set it to
9711 .q CS.Berkeley.EDU .
9712 The effect is that anyone known in the database
9713 gets their outgoing mail stamped as
9714 .q user@CS.Berkeley.EDU ,
9715 but people not listed in the database use the local hostname.
9716 .sh 3 "Creating the database\**"
9718 \**These instructions are known to be incomplete.
9719 Other features are available which provide similar functionality,
9720 e.g., virtual hosting and mapping local addresses into a
9721 generic form as explained in cf/README.
9724 The user database is built from a text file
9728 (in the distribution in the makemap subdirectory).
9729 The text file is a series of lines corresponding to userdb records;
9730 each line has a key and a value separated by white space.
9731 The key is always in the format described above \*-
9736 This file is normally installed in a system directory;
9737 for example, it might be called
9738 .i /etc/mail/userdb .
9739 To make the database version of the map, run the program:
9741 makemap btree /etc/mail/userdb < /etc/mail/userdb
9743 Then create a config file that uses this.
9744 For example, using the V8 M4 configuration, include the
9745 following line in your .mc file:
9747 define(\`confUSERDB_SPEC\', /etc/mail/userdb)
9749 .sh 1 "OTHER CONFIGURATION"
9751 There are some configuration changes that can be made by
9754 This section describes what changes can be made
9755 and what has to be modified to make them.
9756 In most cases this should be unnecessary
9757 unless you are porting
9759 to a new environment.
9760 .sh 2 "Parameters in devtools/OS/$oscf"
9762 These parameters are intended to describe the compilation environment,
9764 and should normally be defined in the operating system
9766 .b "This section needs a complete rewrite."
9769 the new version of the DBM library
9770 that allows multiple databases will be used.
9771 If neither NDBM nor NEWDB are set,
9772 a much less efficient method of alias lookup is used.
9774 If set, use the new database package from Berkeley (from 4.4BSD).
9775 This package is substantially faster than DBM or NDBM.
9776 If NEWDB and NDBM are both set,
9778 will read DBM files,
9779 but will create and use NEWDB files.
9781 Include support for NIS.
9782 If set together with
9786 will create both DBM and NEWDB files if and only if
9787 an alias file includes the substring
9790 This is intended for compatibility with Sun Microsystems'
9792 program used on YP masters.
9794 Compile in support for NIS+.
9796 Compile in support for NetInfo (NeXT stations).
9798 Compile in support for LDAP X500 queries.
9799 Requires libldap and liblber
9800 from the Umich LDAP 3.2 or 3.3 release
9801 or equivalent libraries for other LDAP libraries
9804 Compile in support for Hesiod.
9806 Compile in support for IRIX NSD lookups.
9808 Compile in support for regular expression matching.
9810 Compile in support for DNS map lookups in the
9814 Compile in support for ph lookups.
9816 Compile in support for SASL,
9817 a required component for SMTP Authentication support.
9819 Compile in support for STARTTLS.
9821 Compile in support for the "Entropy Gathering Daemon"
9822 to provide better random data for TLS.
9824 Compile in support for TCP Wrappers.
9825 .ip _PATH_SENDMAILCF
9826 The pathname of the sendmail.cf file.
9827 .ip _PATH_SENDMAILPID
9828 The pathname of the sendmail.pid file.
9830 Compile in support for shared memory, see section about
9831 "/var/spool/mqueue".
9833 Compile in support for contacting external mail filters built with the
9836 There are also several compilation flags to indicate the environment
9841 See the sendmail/README
9842 file for the latest scoop on these flags.
9843 .sh 2 "Parameters in sendmail/conf.h"
9845 Parameters and compilation options
9846 are defined in conf.h.
9847 Most of these need not normally be tweaked;
9848 common parameters are all in sendmail.cf.
9849 However, the sizes of certain primitive vectors, etc.,
9850 are included in this file.
9851 The numbers following the parameters
9852 are their default value.
9854 This document is not the best source of information
9855 for compilation flags in conf.h \(em
9856 see sendmail/README or sendmail/conf.h itself.
9858 .ip "MAXLINE [2048]"
9859 The maximum line length of any input line.
9860 If message lines exceed this length
9861 they will still be processed correctly;
9862 however, header lines,
9863 configuration file lines,
9866 must fit within this limit.
9868 The maximum length of any name,
9869 such as a host or a user name.
9871 The maximum number of parameters to any mailer.
9872 This limits the number of recipients that may be passed in one transaction.
9873 It can be set to any arbitrary number above about 10,
9876 will break up a delivery into smaller batches as needed.
9877 A higher number may reduce load on your system, however.
9878 .ip "MAXQUEUEGROUPS [50]"
9879 The maximum number of queue groups.
9880 .ip "MAXATOM [1000]"
9881 The maximum number of atoms
9883 in a single address.
9886 .q "eric@CS.Berkeley.EDU"
9888 .ip "MAXMAILERS [25]"
9889 The maximum number of mailers that may be defined
9890 in the configuration file.
9891 This value is defined in include/sendmail/sendmail.h.
9892 .ip "MAXRWSETS [200]"
9893 The maximum number of rewriting sets
9894 that may be defined.
9895 The first half of these are reserved for numeric specification
9897 while the upper half are reserved for auto-numbering
9899 Thus, with a value of 200 an attempt to use ``S99'' will succeed,
9900 but ``S100'' will fail.
9901 .ip "MAXPRIORITIES [25]"
9902 The maximum number of values for the
9904 field that may be defined
9907 line in sendmail.cf).
9908 .ip "MAXUSERENVIRON [100]"
9909 The maximum number of items in the user environment
9910 that will be passed to subordinate mailers.
9911 .ip "MAXMXHOSTS [100]"
9912 The maximum number of MX records we will accept for any single host.
9913 .ip "MAXMAPSTACK [12]"
9914 The maximum number of maps that may be "stacked" in a
9917 .ip "MAXMIMEARGS [20]"
9918 The maximum number of arguments in a MIME Content-Type: header;
9919 additional arguments will be ignored.
9920 .ip "MAXMIMENESTING [20]"
9921 The maximum depth to which MIME messages may be nested
9922 (that is, nested Message or Multipart documents;
9923 this does not limit the number of components in a single Multipart document).
9924 .ip "MAXDAEMONS [10]"
9925 The maximum number of sockets sendmail will open for accepting connections
9927 .ip "MAXMACNAMELEN [25]"
9928 The maximum length of a macro name.
9930 A number of other compilation options exist.
9931 These specify whether or not specific code should be compiled in.
9932 Ones marked with \(dg
9937 support for Internet protocol networking is compiled in.
9938 Previous versions of
9942 this old usage is now incorrect.
9944 turn it off in the Makefile
9945 if your system doesn't support the Internet protocols.
9948 support for IPv6 networking is compiled in.
9949 It must be separately enabled by adding
9950 .b DaemonPortOptions
9954 support for ISO protocol networking is compiled in
9955 (it may be appropriate to #define this in the Makefile instead of conf.h).
9958 support for UNIX domain sockets is compiled in.
9959 This is used for control socket support.
9964 routine in use at some sites is used.
9965 This makes an informational log record
9966 for each message processed,
9967 and makes a higher priority log record
9968 for internal system errors.
9969 .b "STRONGLY RECOMMENDED"
9970 \(em if you want no logging, turn it off in the configuration file.
9972 Compile in the code to do ``fuzzy matching'' on the GECOS field
9974 This also requires that the
9976 option be turned on.
9978 Compile in code to use the
9979 Berkeley Internet Name Domain (BIND) server
9980 to resolve TCP/IP host names.
9982 If you are using a non-UNIX mail format,
9983 you can set this flag to turn off special processing
9990 Berkeley user information database package.
9991 This adds a new level of local name expansion
9992 between aliasing and forwarding.
9993 It also uses the NEWDB package.
9994 This may change in future releases.
9996 The following options are normally turned on
9997 in per-operating-system clauses in conf.h.
9999 Compile in the IDENT protocol as defined in RFC 1413.
10000 This defaults on for all systems except Ultrix,
10001 which apparently has the interesting
10003 that when it receives a
10004 .q "host unreachable"
10005 message it closes all open connections to that host.
10006 Since some firewall gateways send this error code
10007 when you access an unauthorized port (such as 113, used by IDENT),
10008 Ultrix cannot receive email from such hosts.
10010 Set all of the compilation parameters appropriate for System V.
10014 instead of System V
10016 to do file locking.
10017 Due to the highly unusual semantics of locks
10020 this should always be used if at all possible.
10022 Set this if your system has the
10025 (if you have multiple group support).
10026 This is the default if SYSTEM5 is
10028 defined or if you are on HPUX.
10030 Set this if you have the
10032 system call (or corresponding library routine).
10036 .ip HASGETDTABLESIZE
10037 Set this if you have the
10038 .i getdtablesize (2)
10041 Set this if you have the
10044 .ip FAST_PID_RECYCLE
10045 Set this if your system can possibly
10046 reuse the same pid in the same second of time.
10048 The mechanism that can be used to get file system capacity information.
10049 The values can be one of
10050 SFS_USTAT (use the ustat(2) syscall),
10051 SFS_4ARGS (use the four argument statfs(2) syscall),
10052 SFS_VFS (use the two argument statfs(2) syscall including <sys/vfs.h>),
10053 SFS_MOUNT (use the two argument statfs(2) syscall including <sys/mount.h>),
10054 SFS_STATFS (use the two argument statfs(2) syscall including <sys/statfs.h>),
10055 SFS_STATVFS (use the two argument statfs(2) syscall including <sys/statvfs.h>),
10057 SFS_NONE (no way to get this information).
10059 The load average type.
10060 Details are described below.
10062 The are several built-in ways of computing the load average.
10064 tries to auto-configure them based on imperfect guesses;
10065 you can select one using the
10074 The kernel stores the load average in the kernel as an array of long integers.
10075 The actual values are scaled by a factor FSCALE
10078 The kernel stores the load average in the kernel as an array of short integers.
10079 The actual values are scaled by a factor FSCALE
10082 The kernel stores the load average in the kernel as an array of
10083 double precision floats.
10085 Use MACH-style load averages.
10089 routine to get the load average as an array of doubles.
10091 Always return zero as the load average.
10092 This is the fallback case.
10100 you may also need to specify
10102 (the path to your system binary)
10105 (the name of the variable containing the load average in the kernel;
10110 .sh 2 "Configuration in sendmail/conf.c"
10112 The following changes can be made in conf.c.
10113 .sh 3 "Built-in Header Semantics"
10115 Not all header semantics are defined in the configuration file.
10116 Header lines that should only be included by certain mailers
10117 (as well as other more obscure semantics)
10118 must be specified in the
10122 This table contains the header name
10123 (which should be in all lower case)
10124 and a set of header control flags (described below),
10127 Normally when the check is made to see if a header line is compatible
10130 will not delete an existing line.
10131 If this flag is set,
10134 even existing header lines.
10136 if this bit is set and the mailer does not have flag bits set
10137 that intersect with the required mailer flags
10138 in the header definition in
10144 If this header field is set,
10145 treat it like a blank line,
10147 it will signal the end of the header
10148 and the beginning of the message text.
10150 Add this header entry
10151 even if one existed in the message before.
10152 If a header entry does not have this bit set,
10154 will not add another header line if a header line
10155 of this name already existed.
10156 This would normally be used to stamp the message
10157 by everyone who handled it.
10160 this is a timestamp
10163 If the number of trace fields in a message
10164 exceeds a preset amount
10165 the message is returned
10166 on the assumption that it has an aliasing loop.
10169 this field contains recipient addresses.
10170 This is used by the
10172 flag to determine who to send to
10173 when it is collecting recipients from the message.
10175 This flag indicates that this field
10176 specifies a sender.
10177 The order of these fields in the
10182 for which field to return error messages to.
10184 Addresses in this header should receive error messages.
10186 This header is a Content-Transfer-Encoding header.
10188 This header is a Content-Type header.
10190 Strip the value from the header (for Bcc:).
10193 Let's look at a sample
10197 .ta 4n +\w'"content-transfer-encoding", 'u
10198 struct hdrinfo HdrInfo[] =
10200 /* originator fields, most to least significant */
10201 "resent-sender", H_FROM,
10202 "resent-from", H_FROM,
10205 "full-name", H_ACHECK,
10206 "errors-to", H_FROM\^|\^H_ERRORSTO,
10207 /* destination fields */
10209 "resent-to", H_RCPT,
10211 "bcc", H_RCPT\^|\^H_STRIPVAL,
10212 /* message identification and control */
10216 "received", H_TRACE\^|\^H_FORCE,
10217 /* miscellaneous fields */
10218 "content-transfer-encoding", H_CTE,
10219 "content-type", H_CTYPE,
10224 This structure indicates that the
10230 all specify recipient addresses.
10233 field will be deleted unless the required mailer flag
10234 (indicated in the configuration file)
10240 fields will terminate the header;
10241 these are used by random dissenters around the network world.
10244 field will always be added,
10245 and can be used to trace messages.
10247 There are a number of important points here.
10249 header fields are not added automatically just because they are in the
10252 they must be specified in the configuration file
10253 in order to be added to the message.
10254 Any header fields mentioned in the configuration file but not
10257 structure have default processing performed;
10259 they are added unless they were in the message already.
10263 structure only specifies cliched processing;
10264 certain headers are processed specially by ad hoc code
10265 regardless of the status specified in
10272 fields are always scanned on ARPANET mail
10273 to determine the sender\**;
10275 \**Actually, this is no longer true in SMTP;
10276 this information is contained in the envelope.
10277 The older ARPANET protocols did not completely distinguish
10278 envelope from header.
10280 this is used to perform the
10281 .q "return to sender"
10287 fields are used to determine the full name of the sender
10289 this is stored in the macro
10291 and used in a number of ways.
10292 .sh 3 "Restricting Use of Email"
10294 If it is necessary to restrict mail through a relay,
10297 routine can be modified.
10298 This routine is called for every recipient address.
10299 It returns an exit status
10300 indicating the status of the message.
10303 accepts the address,
10305 queues the message for a later try,
10308 .sm EX_UNAVAILABLE )
10309 reject the message.
10312 to print an error message
10315 if the message is rejected.
10322 .ta 4n +4n +4n +4n +4n +4n +4n
10325 register ADDRESS *to;
10326 register ENVELOPE *e;
10330 s = stab("private", ST_MAILER, ST_FIND);
10331 if (s != NULL && e\->e_from.q_mailer != LocalMailer &&
10332 to->q_mailer == s->s_mailer)
10334 usrerr("No private net mail allowed through this machine");
10335 return (EX_UNAVAILABLE);
10337 if (MsgSize > 50000 && bitnset(M_LOCALMAILER, to\->q_mailer))
10339 usrerr("Message too large for non-local delivery");
10340 e\->e_flags |= EF_NORETURN;
10341 return (EX_UNAVAILABLE);
10347 This would reject messages greater than 50000 bytes
10348 unless they were local.
10353 to suppress the return of the actual body
10354 of the message in the error return.
10355 The actual use of this routine is highly dependent on the
10357 and use should be limited.
10358 .sh 3 "New Database Map Classes"
10360 New key maps can be added by creating a class initialization function
10361 and a lookup function.
10362 These are then added to the routine
10365 The initialization function is called as
10367 \fIxxx\fP_map_init(MAP *map, char *args)
10371 is an internal data structure.
10374 is a pointer to the portion of the configuration file line
10375 following the map class name;
10376 flags and filenames can be extracted from this line.
10377 The initialization function must return
10379 if it successfully opened the map,
10383 The lookup function is called as
10385 \fIxxx\fP_map_lookup(MAP *map, char buf[], char **av, int *statp)
10389 defines the map internally.
10393 This may be (and often is) used destructively.
10396 is a list of arguments passed in from the rewrite line.
10397 The lookup function should return a pointer to the new value.
10398 If the map lookup fails,
10400 should be set to an exit status code;
10401 in particular, it should be set to
10403 if recovery is to be attempted by the higher level code.
10404 .sh 3 "Queueing Function"
10408 is called to decide if a message should be queued
10409 or processed immediately.
10410 Typically this compares the message priority to the current load average.
10411 The default definition is:
10414 shouldqueue(pri, ctime)
10418 if (CurrentLA < QueueLA)
10420 return (pri > (QueueFactor / (CurrentLA \- QueueLA + 1)));
10423 If the current load average
10426 which is set before this function is called)
10427 is less than the low threshold load average
10436 (that is, it should
10439 If the current load average exceeds the high threshold load average
10448 Otherwise, it computes the function based on the message priority,
10454 and the current and threshold load averages.
10456 An implementation wishing to take the actual age of the message into account
10460 which is the time that the message was first submitted to
10464 parameter is already weighted
10465 by the number of times the message has been tried
10466 (although this tends to lower the priority of the message with time);
10467 the expectation is that the
10469 would be used as an
10471 to ensure that messages are eventually processed.
10472 .sh 3 "Refusing Incoming SMTP Connections"
10475 .i refuseconnections
10478 if incoming SMTP connections should be refused.
10479 The current implementation is based exclusively on the current load average
10480 and the refuse load average option
10487 refuseconnections()
10489 return (RefuseLA > 0 && CurrentLA >= RefuseLA);
10492 A more clever implementation
10493 could look at more system resources.
10494 .sh 3 "Load Average Computation"
10498 returns the current load average (as a rounded integer).
10499 The distribution includes several possible implementations.
10500 If you are porting to a new environment
10501 you may need to add some new tweaks.\**
10503 \**If you do, please send updates to
10504 sendmail@Sendmail.ORG.
10506 .sh 2 "Configuration in sendmail/daemon.c"
10509 .i sendmail/daemon.c
10510 contains a number of routines that are dependent
10511 on the local networking environment.
10512 The version supplied assumes you have BSD style sockets.
10514 In previous releases,
10515 we recommended that you modify the routine
10517 if you wanted to generalize
10522 We now recommend that you create a new keyed map instead.
10525 In this section we assume that
10527 has been compiled with support for LDAP.
10528 .sh 3 "LDAP Recursion"
10530 LDAP Recursion allows you to add types to the search attributes on an
10531 LDAP map specification.
10533 .ip "\-v \fIATTRIBUTE\fP[:\fITYPE\fP[:\fIOBJECTCLASS\fP[|\fIOBJECTCLASS\fP|...]]]
10535 The new \fITYPE\fPs are:
10538 This attribute type specifies the attribute to add to the results string.
10539 This is the default.
10541 Any matches for this attribute are expected to have a value of a
10542 fully qualified distinguished name.
10544 will lookup that DN and apply the attributes requested to the
10545 returned DN record.
10547 Any matches for this attribute are expected to have a value of an
10548 LDAP search filter.
10550 will perform a lookup with the same parameters as the original
10551 search but replaces the search filter with the one specified here.
10553 Any matches for this attribute are expected to have a value of an LDAP URL.
10555 will perform a lookup of that URL and use the results from the attributes
10557 Note however that the search is done using the current LDAP connection,
10558 regardless of what is specified as the scheme, LDAP host, and LDAP
10559 port in the LDAP URL.
10561 Any untyped attributes are considered
10563 attributes as described above.
10565 The optional \fIOBJECTCLASS\fP (| separated) list contains the
10566 objectClass values for which that attribute applies.
10567 If the list is given,
10568 the attribute named will only be used if the LDAP record being returned is a
10569 member of that object class.
10570 Note that if these new value attribute \fITYPE\fPs are used in an
10572 option setting, it will need to be double quoted to prevent
10574 from misparsing the colons.
10576 Note that LDAP recursion attributes which do not ultimately point to an
10577 LDAP record are not considered an error.
10580 Since examples usually help clarify, here is an example which uses all
10581 four of the new types:
10583 O LDAPDefaultSpec=-h ldap.example.com -b dc=example,dc=com
10587 -k (&(objectClass=sendmailMTAAliasObject)(sendmailMTAKey=%0))
10588 -v sendmailMTAAliasValue,mail:NORMAL:inetOrgPerson,
10589 uniqueMember:DN:groupOfUniqueNames,
10590 sendmailMTAAliasSearch:FILTER:sendmailMTAAliasObject,
10591 sendmailMTAAliasURL:URL:sendmailMTAAliasObject
10594 That definition specifies that:
10597 .sm sendmailMTAAliasValue
10598 attribute will be added to the result string regardless of object class.
10602 attribute will be added to the result string if
10603 the LDAP record is a member of the
10609 attribute is a recursive attribute, used only in
10610 .sm groupOfUniqueNames
10611 records, and should contain an LDAP DN pointing to another LDAP record.
10612 The desire here is to return the
10614 attribute from those DNs.
10617 .sm sendmailMTAAliasSearch
10619 .sm sendmailMTAAliasURL
10620 are both used only if referenced in a
10621 .sm sendmailMTAAliasObject .
10622 They are both recursive, the first for a new LDAP search string and the
10623 latter for an LDAP URL.
10626 In this section we assume that
10628 has been compiled with support for STARTTLS.
10629 To properly understand the use of STARTTLS in
10631 it is necessary to understand at least some basics about X.509 certificates
10632 and public key cryptography.
10633 This information can be found in books about SSL/TLS
10634 or on WWW sites, e.g.,
10635 .q http://www.OpenSSL.org/ .
10636 .sh 3 "Certificates for STARTTLS"
10638 When acting as a server,
10640 requires X.509 certificates to support STARTTLS:
10641 one as certificate for the server (ServerCertFile and corresponding
10642 private ServerKeyFile)
10643 at least one root CA (CACertFile),
10644 i.e., a certificate that is used to sign other certificates,
10645 and a path to a directory which contains other CAs (CACertPath).
10646 The file specified via
10648 can contain several certificates of CAs.
10649 The DNs of these certificates are sent
10650 to the client during the TLS handshake (as part of the
10651 CertificateRequest) as the list of acceptable CAs.
10652 However, do not list too many root CAs in that file, otherwise
10653 the TLS handshake may fail; e.g.,
10655 error:14094417:SSL routines:SSL3_READ_BYTES:
10656 sslv3 alert illegal parameter:s3_pkt.c:964:SSL alert number 47
10658 You should probably put only the CA cert into that file
10659 that signed your own cert(s), or at least only those you trust.
10660 The CACertPath directory must contain the hashes of each CA certificate
10661 as filenames (or as links to them).
10662 Symbolic links can be generated with the following
10663 two (Bourne) shell commands:
10665 C=FileName_of_CA_Certificate
10666 ln -s $C `openssl x509 -noout -hash < $C`.0
10668 An X.509 certificate is also required for authentication in client mode
10669 (ClientCertFile and corresponding private ClientKeyFile), however,
10671 will always use STARTTLS when offered by a server.
10672 The client and server certificates can be identical.
10673 Certificates can be obtained from a certificate authority
10674 or created with the help of OpenSSL.
10675 The required format for certificates and private keys is PEM.
10676 To allow for automatic startup of sendmail, private keys
10677 (ServerKeyFile, ClientKeyFile)
10678 must be stored unencrypted.
10679 The keys are only protected by the permissions of the file system.
10680 Never make a private key available to a third party.
10681 .sh 3 "PRNG for STARTTLS"
10683 STARTTLS requires a strong pseudo random number generator (PRNG)
10684 to operate properly.
10685 Depending on the TLS library you use, it may be required to explicitly
10686 initialize the PRNG with random data.
10687 OpenSSL makes use of
10689 if available (this corresponds to the compile flag HASURANDOMDEV).
10690 On systems which lack this support, a random file must be specified in the
10692 file using the option RandFile.
10695 advised to use the "Entropy Gathering Daemon" EGD
10696 from Brian Warner on those systems to provide useful random data.
10699 must be compiled with the flag EGD, and the
10700 RandFile option must point to the EGD socket.
10703 nor EGD are available, you have to make sure
10704 that useful random data is available all the time in RandFile.
10705 If the file hasn't been modified in the last 10 minutes before
10706 it is supposed to be used by
10708 the content is considered obsolete.
10709 One method for generating this file is:
10711 openssl rand -out /etc/mail/randfile -rand \c
10712 .i /path/to/file:... \c
10715 See the OpenSSL documentation for more information.
10716 In this case, the PRNG for TLS is only
10717 seeded with other random data if the
10718 .b DontBlameSendmail
10720 .b InsufficientEntropy
10722 This is most likely not sufficient for certain actions, e.g.,
10723 generation of (temporary) keys.
10725 Please see the OpenSSL documentation or other sources
10726 for further information about certificates, their creation and their usage,
10727 the importance of a good PRNG, and other aspects of TLS.
10728 .sh 2 "Encoding of STARTTLS and AUTH related Macros"
10730 Macros that contain STARTTLS and AUTH related data which comes from outside
10731 sources, e.g., all macros containing information from certificates,
10732 are encoded to avoid problems with non-printable or special characters.
10733 The latter are '\\', '<', '>', '(', ')', '"', '+', and ' '.
10734 All of these characters are replaced by their value in hexadecimal
10735 with a leading '+'.
10738 /C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/
10739 Email=darth+cert@endmail.org
10743 /C=US/ST=California/O=endmail.org/OU=private/
10744 CN=Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
10746 (line breaks have been inserted for readability).
10747 The macros which are subject to this encoding are
10748 {cert_subject}, {cert_issuer}, {cn_subject}, {cn_issuer},
10750 {auth_authen} and {auth_author}.
10751 .sh 1 "ACKNOWLEDGEMENTS"
10756 and many employers have been remarkably patient
10757 about letting me work on a large project
10758 that was not part of my official job.
10759 This includes time on the INGRES Project at
10760 the University of California at Berkeley,
10762 and again on the Mammoth and Titan Projects at Berkeley.
10764 Much of the second wave of improvements
10765 resulting in version 8.1
10766 should be credited to Bryan Costales of the
10767 International Computer Science Institute.
10768 As he passed me drafts of his book on
10770 I was inspired to start working on things again.
10771 Bryan was also available to bounce ideas off of.
10773 Gregory Neil Shapiro
10774 of Worcester Polytechnic Institute
10775 has become instrumental in all phases of
10777 support and development,
10778 and was largely responsible for getting versions 8.8 and 8.9
10781 Many, many people contributed chunks of code and ideas to
10783 It has proven to be a group network effort.
10784 Version 8 in particular was a group project.
10785 The following people and organizations made notable contributions:
10788 John Beck, Hewlett-Packard & Sun Microsystems
10789 Keith Bostic, CSRG, University of California, Berkeley
10790 Andrew Cheng, Sun Microsystems
10791 Michael J. Corrigan, University of California, San Diego
10792 Bryan Costales, International Computer Science Institute & InfoBeat
10793 Pa\*:r (Pell) Emanuelsson
10794 Craig Everhart, Transarc Corporation
10795 Per Hedeland, Ericsson
10796 Tom Ivar Helbekkmo, Norwegian School of Economics
10797 Kari Hurtta, Finnish Meteorological Institute
10798 Allan E. Johannesen, WPI
10799 Jonathan Kamens, OpenVision Technologies, Inc.
10800 Takahiro Kanbe, Fuji Xerox Information Systems Co., Ltd.
10801 Brian Kantor, University of California, San Diego
10802 John Kennedy, Cal State University, Chico
10803 Murray S. Kucherawy, HookUp Communication Corp.
10804 Bruce Lilly, Sony U.S.
10806 Motonori Nakamura, Ritsumeikan University & Kyoto University
10807 John Gardiner Myers, Carnegie Mellon University
10808 Neil Rickert, Northern Illinois University
10809 Gregory Neil Shapiro, WPI
10810 Eric Schnoebelen, Convex Computer Corp.
10811 Eric Wassenaar, National Institute for Nuclear and High Energy Physics, Amsterdam
10812 Randall Winchester, University of Maryland
10813 Christophe Wolfhugel, Pasteur Institute & Herve Schauer Consultants (Paris)
10816 I apologize for anyone I have omitted, misspelled, misattributed, or
10818 At this point, I suspect that at least a hundred people
10819 have contributed code,
10820 and many more have contributed ideas, comments, and encouragement.
10821 I've tried to list them in the RELEASE_NOTES in the distribution directory.
10822 I appreciate their contribution as well.
10824 Special thanks are reserved for Michael Corrigan and Christophe Wolfhugel,
10825 who besides being wonderful guinea pigs and contributors
10826 have also consented to be added to the ``sendmail@Sendmail.ORG'' list
10827 and, by answering the bulk of the questions sent to that list,
10828 have freed me up to do other work.
10830 .+c "COMMAND LINE FLAGS"
10834 Arguments must be presented with flags before addresses.
10837 Select an alternative .cf file which is either
10845 By default the .cf file is chosen based on the operation mode.
10854 if it exists, for all others it is
10857 Set operation mode to
10859 Operation modes are:
10862 m Deliver mail (default)
10863 s Speak SMTP on input side
10864 a\(dg ``Arpanet'' mode (get envelope sender information from header)
10865 d Run as a daemon in background
10866 D Run as a daemon in foreground
10868 v Just verify addresses, don't collect or deliver
10869 i Initialize the alias database
10870 p Print the mail queue
10871 P Print overview over the mail queue (requires shared memory)
10872 h Print the persistent host status database
10873 H Purge expired entries from the persistent host status database
10879 Indicate body type.
10881 Use a different configuration file.
10883 runs as the invoking user (rather than root)
10884 when this flag is specified.
10885 .ip "\-D \fIlogfile\fP"
10886 Send debugging output to the indicated
10890 Set debugging level.
10891 .ip "\-f\ \fIaddr\fP"
10892 The envelope sender address is set to
10894 This address may also be used in the From: header
10895 if that header is missing during initial submission.
10896 The envelope sender address is used as the recipient
10897 for delivery status notifications
10898 and may also appear in a Return-Path: header.
10899 .ip \-F\ \fIname\fP
10900 Sets the full name of this user to
10903 When accepting messages via the command line,
10904 indicate that they are for relay (gateway) submission.
10905 sendmail may complain about syntactically invalid messages,
10906 e.g., unqualified host names,
10907 rather than fixing them when this flag is set.
10908 sendmail will not do any canonicalization in this mode.
10909 .ip "\-h\ \fIcnt\fP"
10914 This represents the number of times this message has been processed
10917 (to the extent that it is supported by the underlying networks).
10919 is incremented during processing,
10924 throws away the message with an error.
10925 .ip "\-L \fItag\fP"
10926 Sets the identifier used for syslog.
10927 Note that this identifier is set
10928 as early as possible.
10933 before the command line arguments
10936 Don't do aliasing or forwarding.
10937 .ip "\-N \fInotifications\fP"
10938 Tag all addresses being sent as wanting the indicated
10940 which consists of the word
10942 or a comma-separated list of
10947 for successful delivery,
10949 and a message that is stuck in a queue somewhere.
10952 .ip "\-r\ \fIaddr\fP"
10953 An obsolete form of
10955 .ip \-o\fIx\|value\fP
10960 These options are described in Section 5.6.
10961 .ip \-O\fIoption\fP\fB=\fP\fIvalue\fP
10966 (for long form option names).
10967 These options are described in Section 5.6.
10968 .ip \-M\fIx\|value\fP
10973 .ip \-p\fIprotocol\fP
10974 Set the sending protocol.
10975 Programs are encouraged to set this.
10976 The protocol field can be in the form
10980 to set both the sending protocol and sending host.
10983 sets the sending protocol to UUCP
10984 and the sending host to uunet.
10985 (Some existing programs use \-oM to set the r and s macros;
10986 this is equivalent to using \-p.)
10988 Try to process the queued up mail.
10989 If the time is given,
10992 will start one or more processes to run through the queue(s) at the specified
10993 time interval to deliver queued mail; otherwise, it only runs once.
10994 Each of these processes acts on a workgroup.
10995 These processes are also known as workgroup processes or WGP's for short.
10996 Each workgroup is responsible for controlling the processing of one or
10997 more queues; workgroups help manage the use of system resources by sendmail.
10998 Each workgroup may have one or more children concurrently processing
10999 queues depending on the setting of \fIMaxQueueChildren\fP.
11001 Similar to \-q with a time argument,
11002 except that instead of periodically starting WGP's
11003 sendmail starts persistent WGP's
11004 that alternate between processing queues and sleeping.
11005 The sleep time is specified by the time argument; it defaults to 1 second,
11006 except that a WGP always sleeps at least 5 seconds if their queues were
11007 empty in the previous run.
11008 Persistent processes are managed by a queue control process (QCP).
11009 The QCP is the parent process of the WGP's.
11010 Typically the QCP will be the sendmail daemon (when started with \-bd or \-bD)
11011 or a special process (named Queue control) (when started without \-bd or \-bD).
11012 If a persistent WGP ceases to be active for some reason
11013 another WGP will be started by the QCP for the same workgroup
11014 in most cases. When a persistent WGP has core dumped, the debug flag
11015 \fIno_persistent_restart\fP is set or the specific persistent WGP has been
11016 restarted too many times already then the WGP will not be started again
11017 and a message will be logged to this effect.
11018 To stop (SIGTERM) or restart (SIGHUP) persistent WGP's the appropriate
11019 signal should be sent to the QCP. The QCP will propagate the signal to all of
11020 the WGP's and if appropriate restart the persistent WGP's.
11022 Run the jobs in the queue group
11025 .ip \-q[!]\fIXstring\fP
11026 Run the queue once,
11027 limiting the jobs to those matching
11033 to limit based on queue identifier,
11035 to limit based on recipient,
11037 to limit based on sender,
11040 to limit based on quarantine reason for quarantined jobs.
11041 A particular queued job is accepted if one of the corresponding attributes
11042 contains the indicated
11044 The optional ! character negates the condition tested.
11047 flags are permitted,
11048 with items with the same key letter
11050 together, and items with different key letters
11054 Quarantine a normal queue items with the given reason or
11055 unquarantine quarantined queue items if no reason is given.
11056 This should only be used with some sort of item matching using
11057 .b \-q[!]\fIXstring\fP
11058 as described above.
11060 What information you want returned if the message bounces;
11064 for headers only or
11066 for headers plus body.
11067 This is a request only;
11068 the other end is not required to honor the parameter.
11071 is specified local bounces also return only the headers.
11073 Read the header for
11078 lines, and send to everyone listed in those lists.
11081 line will be deleted before sending.
11082 Any addresses in the argument vector will be deleted
11083 from the send list.
11087 is passed with the envelope of the message
11088 and returned if the message bounces.
11089 .ip "\-X \fIlogfile\fP"
11090 Log all traffic in and out of
11094 for debugging mailer problems.
11095 This produces a lot of data very quickly and should be used sparingly.
11097 There are a number of options that may be specified as
11099 These are the e, i, m, and v options.
11102 may be specified as the
11105 The DSN related options
11113 .+c "QUEUE FILE FORMATS"
11115 This appendix describes the format of the queue files.
11116 These files live in a queue directory.
11117 The individual qf, hf, Qf, df, and xf files
11118 may be stored in separate
11124 if they are present in the queue directory.
11126 All queue files have the name
11136 The individual letters in the
11153 Encoded envelope number
11155 At least five decimal digits of the process ID
11157 All files with the same id collectively define one message.
11158 Due to the use of memory-buffered files,
11159 some of these files may never appear on disk.
11164 The queue control file.
11165 This file contains the information necessary to process the job.
11167 The same as a queue control file, but for a quarantined queue job.
11170 The message body (excluding the header) is kept in this file.
11171 Sometimes the df file is not stored in the same directory as the qf file;
11173 the qf file contains a `d' record which names the queue directory
11174 that contains the df file.
11177 This is an image of the
11179 file when it is being rebuilt.
11180 It should be renamed to a
11185 existing during the life of a session
11186 showing everything that happens
11187 during that session.
11188 Sometimes the xf file must be generated before a queue group has been selected;
11190 the xf file will be stored in a directory of the default queue group.
11192 A ``lost'' queue control file.
11198 if there is a severe (configuration) problem that cannot be solved without
11199 human intervention.
11200 Search the logfile for the queue file id to figure out what happened.
11201 After you resolved the problem, you can rename the
11207 The queue control file is structured as a series of lines
11208 each beginning with a code letter.
11209 The lines are as follows:
11211 The version number of the queue file format,
11214 binaries to read queue files created by older versions.
11215 Defaults to version zero.
11216 Must be the first line of the file if present.
11217 For 8.12 the version number is 6.
11219 The information given by the AUTH= parameter of the
11222 if sendmail has been called directly.
11224 A header definition.
11225 There may be any number of these lines.
11226 The order is important:
11227 they represent the order in the final message.
11228 These use the same syntax
11229 as header definitions in the configuration file.
11231 The controlling address.
11233 .q localuser:aliasname .
11234 Recipient addresses following this line
11235 will be flagged so that deliveries will be run as the
11237 (a user name from the /etc/passwd file);
11239 is the name of the alias that expanded to this address
11240 (used for printing messages).
11242 The quarantine reason for quarantined queue items.
11244 The ``original recipient'',
11245 specified by the ORCPT= field in an ESMTP transaction.
11246 Used exclusively for Delivery Status Notifications.
11247 It applies only to the following `R' line.
11249 The ``final recipient''
11250 used for Delivery Status Notifications.
11251 It applies only to the following `R' line.
11253 A recipient address.
11254 This will normally be completely aliased,
11255 but is actually realiased when the job is processed.
11256 There will be one line for each recipient.
11258 also include a leading colon-terminated list of flags,
11260 `S' to return a message on successful final delivery,
11261 `F' to return a message on failure,
11262 `D' to return a message if the message is delayed,
11263 `B' to indicate that the body should be returned,
11264 `N' to suppress returning the body,
11266 `P' to declare this as a ``primary'' (command line or SMTP-session) address.
11268 The sender address.
11269 There may only be one of these lines.
11271 The job creation time.
11272 This is used to compute when to time out the job.
11274 The current message priority.
11275 This is used to order the queue.
11276 Higher numbers mean lower priorities.
11277 The priority changes
11278 as the message sits in the queue.
11279 The initial priority depends on the message class
11280 and the size of the message.
11283 This line is printed by the
11286 and is generally used to store status information.
11287 It can contain any text.
11289 Flag bits, represented as one letter per flag.
11290 Defined flag bits are
11292 indicating that this is a response message
11295 indicating that a warning message has been sent
11296 announcing that the mail has been delayed.
11297 Other flag bits are:
11299 the body contains 8bit data,
11301 a Bcc: header should be removed,
11303 the mail has RET parameters (see RFC 1894),
11305 the body of the message should not be returned
11306 in case of an error,
11308 the envelope has been split.
11310 The total number of delivery attempts.
11312 The time (as seconds since January 1, 1970)
11313 of the last delivery attempt.
11315 If the df file is in a different directory than the qf file,
11316 then a `d' record is present,
11317 specifying the directory in which the df file resides.
11319 The i-number of the data file;
11320 this can be used to recover your mail queue
11321 after a disastrous disk crash.
11323 A macro definition.
11324 The values of certain macros
11325 are passed through to the queue run phase.
11328 The remainder of the line is a text string defining the body type.
11329 If this field is missing,
11330 the body type is assumed to be
11332 and no special processing is attempted.
11338 The original envelope id (from the ESMTP transaction).
11339 For Deliver Status Notifications only.
11342 the following is a queue file sent to
11343 .q eric@mammoth.Berkeley.EDU
11345 .q bostic@okeeffe.CS.Berkeley.EDU \**:
11347 \**This example is contrived and probably inaccurate for your environment.
11348 Glance over it to get an idea;
11349 nothing can replace looking at what your own system generates.
11360 Ceric:100:1000:sendmail@vangogh.CS.Berkeley.EDU
11361 RPFD:eric@mammoth.Berkeley.EDU
11362 RPFD:bostic@okeeffe.CS.Berkeley.EDU
11363 H?P?Return-path: <^g>
11364 H??Received: by vangogh.CS.Berkeley.EDU (5.108/2.7) id AAA06703;
11365 Fri, 17 Jul 1992 00:28:55 -0700
11366 H??Received: from mail.CS.Berkeley.EDU by vangogh.CS.Berkeley.EDU (5.108/2.7)
11367 id AAA06698; Fri, 17 Jul 1992 00:28:54 -0700
11368 H??Received: from [128.32.31.21] by mail.CS.Berkeley.EDU (5.96/2.5)
11369 id AA22777; Fri, 17 Jul 1992 03:29:14 -0400
11370 H??Received: by foo.bar.baz.de (5.57/Ultrix3.0-C)
11371 id AA22757; Fri, 17 Jul 1992 09:31:25 GMT
11372 H?F?From: eric@foo.bar.baz.de (Eric Allman)
11373 H?x?Full-name: Eric Allman
11374 H??Message-id: <9207170931.AA22757@foo.bar.baz.de>
11375 H??To: sendmail@vangogh.CS.Berkeley.EDU
11376 H??Subject: this is an example message
11379 the person who sent the message,
11380 the submission time
11381 (in seconds since January 1, 1970),
11382 the message priority,
11385 and the headers for the message.
11386 .+c "SUMMARY OF SUPPORT FILES"
11388 This is a summary of the support files
11391 creates or generates.
11392 Many of these can be changed by editing the sendmail.cf file;
11393 check there to find the actual pathnames.
11395 .ip "/usr/\*(SD/sendmail"
11398 .ip /usr/\*(SB/newaliases
11399 A link to /usr/\*(SD/sendmail;
11400 causes the alias database to be rebuilt.
11401 Running this program is completely equivalent to giving
11406 .ip /usr/\*(SB/mailq
11407 Prints a listing of the mail queue.
11408 This program is equivalent to using the
11412 .ip /etc/mail/sendmail.cf
11413 The configuration file,
11415 .ip /etc/mail/helpfile
11416 The SMTP help file.
11417 .ip /etc/mail/statistics
11418 A statistics file; need not be present.
11419 .ip /etc/mail/sendmail.pid
11420 Created in daemon mode;
11421 it contains the process id of the current SMTP daemon.
11422 If you use this in scripts;
11423 use ``head \-1'' to get just the first line;
11424 the second line contains the command line used to invoke the daemon,
11425 and later versions of
11427 may add more information to subsequent lines.
11428 .ip /etc/mail/aliases
11429 The textual version of the alias file.
11430 .ip /etc/mail/aliases.db
11434 .ip /etc/mail/aliases.{pag,dir}
11438 .ip /var/spool/mqueue
11439 The directory in which the mail queue(s)
11440 and temporary files reside.
11441 .ip /var/spool/mqueue/qf*
11442 Control (queue) files for messages.
11443 .ip /var/spool/mqueue/df*
11445 .ip /var/spool/mqueue/tf*
11446 Temporary versions of the qf files,
11447 used during queue file rebuild.
11448 .ip /var/spool/mqueue/xf*
11449 A transcript of the current session.
11456 This page intentionally left blank;
11457 replace it with a blank sheet for double-sided output.
11469 .\"INSTALLATION AND OPERATION GUIDE
11474 .\"Version $Revision: 8.749 $
11482 .\" remove some things to avoid "out of temp file space" problem
11502 This page intentionally left blank;
11503 replace it with a blank sheet for double-sided output.
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