2 SENDMAIL CONFIGURATION FILES
4 This document describes the sendmail configuration files. It
5 explains how to create a sendmail.cf file for use with sendmail.
6 It also describes how to set options for sendmail which are explained
7 in the Sendmail Installation and Operation guide (doc/op/op.me).
9 To get started, you may want to look at tcpproto.mc (for TCP-only
10 sites) and clientproto.mc (for clusters of clients using a single
11 mail host), or the generic-*.mc files as operating system-specific
16 INTRODUCTION AND EXAMPLE
17 A BRIEF INTRODUCTION TO M4
27 MASQUERADING AND RELAYING
28 USING LDAP FOR ALIASES, MAPS, AND CLASSES
30 ANTI-SPAM CONFIGURATION CONTROL
34 ADDING NEW MAILERS OR RULESETS
35 ADDING NEW MAIL FILTERS
36 QUEUE GROUP DEFINITIONS
37 NON-SMTP BASED CONFIGURATIONS
39 ACCEPTING MAIL FOR MULTIPLE NAMES
41 USING USERDB TO MAP FULL NAMES
42 MISCELLANEOUS SPECIAL FEATURES
44 TWEAKING CONFIGURATION OPTIONS
45 MESSAGE SUBMISSION PROGRAM
46 FORMAT OF FILES AND MAPS
48 ADMINISTRATIVE DETAILS
51 +--------------------------+
52 | INTRODUCTION AND EXAMPLE |
53 +--------------------------+
55 Configuration files are contained in the subdirectory "cf", with a
56 suffix ".mc". They must be run through "m4" to produce a ".cf" file.
57 You must pre-load "cf.m4":
59 m4 ${CFDIR}/m4/cf.m4 config.mc > config.cf
61 Alternatively, you can simply:
66 where ${CFDIR} is the root of the cf directory and config.mc is the
67 name of your configuration file. If you are running a version of M4
68 that understands the __file__ builtin (versions of GNU m4 >= 0.75 do
69 this, but the versions distributed with 4.4BSD and derivatives do not)
70 or the -I flag (ditto), then ${CFDIR} can be in an arbitrary directory.
71 For "traditional" versions, ${CFDIR} ***MUST*** be "..", or you MUST
72 use -D_CF_DIR_=/path/to/cf/dir/ -- note the trailing slash! For example:
74 m4 -D_CF_DIR_=${CFDIR}/ ${CFDIR}/m4/cf.m4 config.mc > config.cf
76 Let's examine a typical .mc file:
80 # Copyright (c) 1998-2005 Sendmail, Inc. and its suppliers.
81 # All rights reserved.
82 # Copyright (c) 1983 Eric P. Allman. All rights reserved.
83 # Copyright (c) 1988, 1993
84 # The Regents of the University of California. All rights reserved.
86 # By using this file, you agree to the terms and conditions set
87 # forth in the LICENSE file which can be found at the top level of
88 # the sendmail distribution.
92 # This is a Berkeley-specific configuration file for HP-UX 9.x.
93 # It applies only to the Computer Science Division at Berkeley,
94 # and should not be used elsewhere. It is provided on the sendmail
95 # distribution as a sample only. To create your own configuration
96 # file, create an appropriate domain file in ../domain, change the
97 # `DOMAIN' macro below to reference that file, and copy the result
98 # to a name of your own choosing.
102 The divert(-1) will delete the crud in the resulting output file.
103 The copyright notice can be replaced by whatever your lawyers require;
104 our lawyers require the one that is included in these files. A copyleft
105 is a copyright by another name. The divert(0) restores regular output.
107 VERSIONID(`<SCCS or RCS version id>')
109 VERSIONID is a macro that stuffs the version information into the
110 resulting file. You could use SCCS, RCS, CVS, something else, or
111 omit it completely. This is not the same as the version id included
112 in SMTP greeting messages -- this is defined in m4/version.m4.
116 You must specify an OSTYPE to properly configure things such as the
117 pathname of the help and status files, the flags needed for the local
118 mailer, and other important things. If you omit it, you will get an
119 error when you try to build the configuration. Look at the ostype
120 directory for the list of known operating system types.
122 DOMAIN(`CS.Berkeley.EDU')dnl
124 This example is specific to the Computer Science Division at Berkeley.
125 You can use "DOMAIN(`generic')" to get a sufficiently bland definition
126 that may well work for you, or you can create a customized domain
127 definition appropriate for your environment.
132 These describe the mailers used at the default CS site. The local
133 mailer is always included automatically. Beware: MAILER declarations
134 should only be followed by LOCAL_* sections. The general rules are
135 that the order should be:
141 local macro definitions
147 There are a few exceptions to this rule. Local macro definitions which
148 influence a FEATURE() should be done before that feature. For example,
149 a define(`PROCMAIL_MAILER_PATH', ...) should be done before
150 FEATURE(`local_procmail').
152 *******************************************************************
153 *** BE SURE YOU CUSTOMIZE THESE FILES! They have some ***
154 *** Berkeley-specific assumptions built in, such as the name ***
155 *** of their UUCP-relay. You'll want to create your own ***
156 *** domain description, and use that in place of ***
157 *** domain/Berkeley.EDU.m4. ***
158 *******************************************************************
161 +----------------------------+
162 | A BRIEF INTRODUCTION TO M4 |
163 +----------------------------+
165 Sendmail uses the M4 macro processor to ``compile'' the configuration
166 files. The most important thing to know is that M4 is stream-based,
167 that is, it doesn't understand about lines. For this reason, in some
168 places you may see the word ``dnl'', which stands for ``delete
169 through newline''; essentially, it deletes all characters starting
170 at the ``dnl'' up to and including the next newline character. In
171 most cases sendmail uses this only to avoid lots of unnecessary
172 blank lines in the output.
174 Other important directives are define(A, B) which defines the macro
175 ``A'' to have value ``B''. Macros are expanded as they are read, so
176 one normally quotes both values to prevent expansion. For example,
178 define(`SMART_HOST', `smart.foo.com')
180 One word of warning: M4 macros are expanded even in lines that appear
181 to be comments. For example, if you have
183 # See FEATURE(`foo') above
185 it will not do what you expect, because the FEATURE(`foo') will be
186 expanded. This also applies to
188 # And then define the $X macro to be the return address
190 because ``define'' is an M4 keyword. If you want to use them, surround
191 them with directed quotes, `like this'.
193 Since m4 uses single quotes (opening "`" and closing "'") to quote
194 arguments, those quotes can't be used in arguments. For example,
195 it is not possible to define a rejection message containing a single
196 quote. Usually there are simple workarounds by changing those
197 messages; in the worst case it might be ok to change the value
198 directly in the generated .cf file, which however is not advised.
204 This package requires a post-V7 version of m4; if you are running the
205 4.2bsd, SysV.2, or 7th Edition version. SunOS's /usr/5bin/m4 or
206 BSD-Net/2's m4 both work. GNU m4 version 1.1 or later also works.
207 Unfortunately, the M4 on BSDI 1.0 doesn't work -- you'll have to use a
208 Net/2 or GNU version. GNU m4 is available from
209 ftp://ftp.gnu.org/pub/gnu/m4/m4-1.4.tar.gz (check for the latest version).
210 EXCEPTIONS: DEC's m4 on Digital UNIX 4.x is broken (3.x is fine). Use GNU
218 sendmail 8.9 has introduced a new configuration directory for sendmail
219 related files, /etc/mail. The new files available for sendmail 8.9 --
220 the class {R} /etc/mail/relay-domains and the access database
221 /etc/mail/access -- take advantage of this new directory. Beginning with
222 8.10, all files will use this directory by default (some options may be
223 set by OSTYPE() files). This new directory should help to restore
224 uniformity to sendmail's file locations.
226 Below is a table of some of the common changes:
228 Old filename New filename
229 ------------ ------------
230 /etc/bitdomain /etc/mail/bitdomain
231 /etc/domaintable /etc/mail/domaintable
232 /etc/genericstable /etc/mail/genericstable
233 /etc/uudomain /etc/mail/uudomain
234 /etc/virtusertable /etc/mail/virtusertable
235 /etc/userdb /etc/mail/userdb
237 /etc/aliases /etc/mail/aliases
238 /etc/sendmail/aliases /etc/mail/aliases
239 /etc/ucbmail/aliases /etc/mail/aliases
240 /usr/adm/sendmail/aliases /etc/mail/aliases
241 /usr/lib/aliases /etc/mail/aliases
242 /usr/lib/mail/aliases /etc/mail/aliases
243 /usr/ucblib/aliases /etc/mail/aliases
245 /etc/sendmail.cw /etc/mail/local-host-names
246 /etc/mail/sendmail.cw /etc/mail/local-host-names
247 /etc/sendmail/sendmail.cw /etc/mail/local-host-names
249 /etc/sendmail.ct /etc/mail/trusted-users
251 /etc/sendmail.oE /etc/mail/error-header
253 /etc/sendmail.hf /etc/mail/helpfile
254 /etc/mail/sendmail.hf /etc/mail/helpfile
255 /usr/ucblib/sendmail.hf /etc/mail/helpfile
256 /etc/ucbmail/sendmail.hf /etc/mail/helpfile
257 /usr/lib/sendmail.hf /etc/mail/helpfile
258 /usr/share/lib/sendmail.hf /etc/mail/helpfile
259 /usr/share/misc/sendmail.hf /etc/mail/helpfile
260 /share/misc/sendmail.hf /etc/mail/helpfile
262 /etc/service.switch /etc/mail/service.switch
264 /etc/sendmail.st /etc/mail/statistics
265 /etc/mail/sendmail.st /etc/mail/statistics
266 /etc/mailer/sendmail.st /etc/mail/statistics
267 /etc/sendmail/sendmail.st /etc/mail/statistics
268 /usr/lib/sendmail.st /etc/mail/statistics
269 /usr/ucblib/sendmail.st /etc/mail/statistics
271 Note that all of these paths actually use a new m4 macro MAIL_SETTINGS_DIR
272 to create the pathnames. The default value of this variable is
273 `/etc/mail/'. If you set this macro to a different value, you MUST include
276 Notice: all filenames used in a .mc (or .cf) file should be absolute
277 (starting at the root, i.e., with '/'). Relative filenames most
278 likely cause surprises during operations (unless otherwise noted).
285 You MUST define an operating system environment, or the configuration
286 file build will puke. There are several environments available; look
287 at the "ostype" directory for the current list. This macro changes
288 things like the location of the alias file and queue directory. Some
289 of these files are identical to one another.
291 It is IMPERATIVE that the OSTYPE occur before any MAILER definitions.
292 In general, the OSTYPE macro should go immediately after any version
293 information, and MAILER definitions should always go last.
295 Operating system definitions are usually easy to write. They may define
296 the following variables (everything defaults, so an ostype file may be
297 empty). Unfortunately, the list of configuration-supported systems is
298 not as broad as the list of source-supported systems, since many of
299 the source contributors do not include corresponding ostype files.
301 ALIAS_FILE [/etc/mail/aliases] The location of the text version
302 of the alias file(s). It can be a comma-separated
303 list of names (but be sure you quote values with
304 commas in them -- for example, use
305 define(`ALIAS_FILE', `a,b')
306 to get "a" and "b" both listed as alias files;
307 otherwise the define() primitive only sees "a").
308 HELP_FILE [/etc/mail/helpfile] The name of the file
309 containing information printed in response to
310 the SMTP HELP command.
311 QUEUE_DIR [/var/spool/mqueue] The directory containing
312 queue files. To use multiple queues, supply
313 a value ending with an asterisk. For
314 example, /var/spool/mqueue/qd* will use all of the
315 directories or symbolic links to directories
316 beginning with 'qd' in /var/spool/mqueue as queue
317 directories. The names 'qf', 'df', and 'xf' are
318 reserved as specific subdirectories for the
319 corresponding queue file types as explained in
320 doc/op/op.me. See also QUEUE GROUP DEFINITIONS.
321 MSP_QUEUE_DIR [/var/spool/clientmqueue] The directory containing
322 queue files for the MSP (Mail Submission Program,
323 see sendmail/SECURITY).
324 STATUS_FILE [/etc/mail/statistics] The file containing status
326 LOCAL_MAILER_PATH [/bin/mail] The program used to deliver local mail.
327 LOCAL_MAILER_FLAGS [Prmn9] The flags used by the local mailer. The
328 flags lsDFMAw5:/|@q are always included.
329 LOCAL_MAILER_ARGS [mail -d $u] The arguments passed to deliver local
331 LOCAL_MAILER_MAX [undefined] If defined, the maximum size of local
332 mail that you are willing to accept.
333 LOCAL_MAILER_MAXMSGS [undefined] If defined, the maximum number of
334 messages to deliver in a single connection. Only
335 useful for LMTP local mailers.
336 LOCAL_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
337 that ARRIVE from an address that resolves to the
338 local mailer and which are converted to MIME will be
339 labeled with this character set.
340 LOCAL_MAILER_EOL [undefined] If defined, the string to use as the
341 end of line for the local mailer.
342 LOCAL_MAILER_DSN_DIAGNOSTIC_CODE
343 [X-Unix] The DSN Diagnostic-Code value for the
344 local mailer. This should be changed with care.
345 LOCAL_SHELL_PATH [/bin/sh] The shell used to deliver piped email.
346 LOCAL_SHELL_FLAGS [eu9] The flags used by the shell mailer. The
347 flags lsDFM are always included.
348 LOCAL_SHELL_ARGS [sh -c $u] The arguments passed to deliver "prog"
350 LOCAL_SHELL_DIR [$z:/] The directory search path in which the
352 LOCAL_MAILER_QGRP [undefined] The queue group for the local mailer.
353 USENET_MAILER_PATH [/usr/lib/news/inews] The name of the program
355 USENET_MAILER_FLAGS [rsDFMmn] The mailer flags for the usenet mailer.
356 USENET_MAILER_ARGS [-m -h -n] The command line arguments for the
357 usenet mailer. NOTE: Some versions of inews
358 (such as those shipped with newer versions of INN)
359 use different flags. Double check the defaults
360 against the inews man page.
361 USENET_MAILER_MAX [undefined] The maximum size of messages that will
362 be accepted by the usenet mailer.
363 USENET_MAILER_QGRP [undefined] The queue group for the usenet mailer.
364 SMTP_MAILER_FLAGS [undefined] Flags added to SMTP mailer. Default
365 flags are `mDFMuX' for all SMTP-based mailers; the
366 "esmtp" mailer adds `a'; "smtp8" adds `8'; and
368 RELAY_MAILER_FLAGS [undefined] Flags added to the relay mailer. Default
369 flags are `mDFMuX' for all SMTP-based mailers; the
370 relay mailer adds `a8'. If this is not defined,
371 then SMTP_MAILER_FLAGS is used.
372 SMTP_MAILER_MAX [undefined] The maximum size of messages that will
373 be transported using the smtp, smtp8, esmtp, or dsmtp
375 SMTP_MAILER_MAXMSGS [undefined] If defined, the maximum number of
376 messages to deliver in a single connection for the
377 smtp, smtp8, esmtp, or dsmtp mailers.
378 SMTP_MAILER_MAXRCPTS [undefined] If defined, the maximum number of
379 recipients to deliver in a single connection for the
380 smtp, smtp8, esmtp, or dsmtp mailers.
381 SMTP_MAILER_ARGS [TCP $h] The arguments passed to the smtp mailer.
382 About the only reason you would want to change this
383 would be to change the default port.
384 ESMTP_MAILER_ARGS [TCP $h] The arguments passed to the esmtp mailer.
385 SMTP8_MAILER_ARGS [TCP $h] The arguments passed to the smtp8 mailer.
386 DSMTP_MAILER_ARGS [TCP $h] The arguments passed to the dsmtp mailer.
387 RELAY_MAILER_ARGS [TCP $h] The arguments passed to the relay mailer.
388 SMTP_MAILER_QGRP [undefined] The queue group for the smtp mailer.
389 ESMTP_MAILER_QGRP [undefined] The queue group for the esmtp mailer.
390 SMTP8_MAILER_QGRP [undefined] The queue group for the smtp8 mailer.
391 DSMTP_MAILER_QGRP [undefined] The queue group for the dsmtp mailer.
392 RELAY_MAILER_QGRP [undefined] The queue group for the relay mailer.
393 RELAY_MAILER_MAXMSGS [undefined] If defined, the maximum number of
394 messages to deliver in a single connection for the
396 SMTP_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
397 that ARRIVE from an address that resolves to one of
398 the SMTP mailers and which are converted to MIME will
399 be labeled with this character set.
400 SMTP_MAILER_LL [990] The maximum line length for SMTP mailers
401 (except the relay mailer).
402 RELAY_MAILER_LL [2040] The maximum line length for the relay mailer.
403 UUCP_MAILER_PATH [/usr/bin/uux] The program used to send UUCP mail.
404 UUCP_MAILER_FLAGS [undefined] Flags added to UUCP mailer. Default
405 flags are `DFMhuU' (and `m' for uucp-new mailer,
406 minus `U' for uucp-dom mailer).
407 UUCP_MAILER_ARGS [uux - -r -z -a$g -gC $h!rmail ($u)] The arguments
408 passed to the UUCP mailer.
409 UUCP_MAILER_MAX [100000] The maximum size message accepted for
410 transmission by the UUCP mailers.
411 UUCP_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
412 that ARRIVE from an address that resolves to one of
413 the UUCP mailers and which are converted to MIME will
414 be labeled with this character set.
415 UUCP_MAILER_QGRP [undefined] The queue group for the UUCP mailers.
416 FAX_MAILER_PATH [/usr/local/lib/fax/mailfax] The program used to
418 FAX_MAILER_ARGS [mailfax $u $h $f] The arguments passed to the FAX
420 FAX_MAILER_MAX [100000] The maximum size message accepted for
422 POP_MAILER_PATH [/usr/lib/mh/spop] The pathname of the POP mailer.
423 POP_MAILER_FLAGS [Penu] Flags added to POP mailer. Flags lsDFMq
425 POP_MAILER_ARGS [pop $u] The arguments passed to the POP mailer.
426 POP_MAILER_QGRP [undefined] The queue group for the pop mailer.
427 PROCMAIL_MAILER_PATH [/usr/local/bin/procmail] The path to the procmail
428 program. This is also used by
429 FEATURE(`local_procmail').
430 PROCMAIL_MAILER_FLAGS [SPhnu9] Flags added to Procmail mailer. Flags
431 DFM are always set. This is NOT used by
432 FEATURE(`local_procmail'); tweak LOCAL_MAILER_FLAGS
434 PROCMAIL_MAILER_ARGS [procmail -Y -m $h $f $u] The arguments passed to
435 the Procmail mailer. This is NOT used by
436 FEATURE(`local_procmail'); tweak LOCAL_MAILER_ARGS
438 PROCMAIL_MAILER_MAX [undefined] If set, the maximum size message that
439 will be accepted by the procmail mailer.
440 PROCMAIL_MAILER_QGRP [undefined] The queue group for the procmail mailer.
441 MAIL11_MAILER_PATH [/usr/etc/mail11] The path to the mail11 mailer.
442 MAIL11_MAILER_FLAGS [nsFx] Flags for the mail11 mailer.
443 MAIL11_MAILER_ARGS [mail11 $g $x $h $u] Arguments passed to the mail11
445 MAIL11_MAILER_QGRP [undefined] The queue group for the mail11 mailer.
446 PH_MAILER_PATH [/usr/local/etc/phquery] The path to the phquery
448 PH_MAILER_FLAGS [ehmu] Flags for the phquery mailer. Flags nrDFM
450 PH_MAILER_ARGS [phquery -- $u] -- arguments to the phquery mailer.
451 PH_MAILER_QGRP [undefined] The queue group for the ph mailer.
452 CYRUS_MAILER_FLAGS [Ah5@/:|] The flags used by the cyrus mailer. The
453 flags lsDFMnPq are always included.
454 CYRUS_MAILER_PATH [/usr/cyrus/bin/deliver] The program used to deliver
456 CYRUS_MAILER_ARGS [deliver -e -m $h -- $u] The arguments passed
457 to deliver cyrus mail.
458 CYRUS_MAILER_MAX [undefined] If set, the maximum size message that
459 will be accepted by the cyrus mailer.
460 CYRUS_MAILER_USER [cyrus:mail] The user and group to become when
461 running the cyrus mailer.
462 CYRUS_MAILER_QGRP [undefined] The queue group for the cyrus mailer.
463 CYRUS_BB_MAILER_FLAGS [u] The flags used by the cyrusbb mailer.
464 The flags lsDFMnP are always included.
465 CYRUS_BB_MAILER_ARGS [deliver -e -m $u] The arguments passed
466 to deliver cyrusbb mail.
467 CYRUSV2_MAILER_FLAGS [A@/:|m] The flags used by the cyrusv2 mailer. The
468 flags lsDFMnqXz are always included.
469 CYRUSV2_MAILER_MAXMSGS [undefined] If defined, the maximum number of
470 messages to deliver in a single connection for the
472 CYRUSV2_MAILER_MAXRCPTS [undefined] If defined, the maximum number of
473 recipients to deliver in a single connection for the
475 CYRUSV2_MAILER_ARGS [FILE /var/imap/socket/lmtp] The arguments passed
476 to the cyrusv2 mailer. This can be used to
477 change the name of the Unix domain socket, or
478 to switch to delivery via TCP (e.g., `TCP $h lmtp')
479 CYRUSV2_MAILER_QGRP [undefined] The queue group for the cyrusv2 mailer.
480 CYRUSV2_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
481 that ARRIVE from an address that resolves to one the
482 Cyrus mailer and which are converted to MIME will
483 be labeled with this character set.
484 confEBINDIR [/usr/libexec] The directory for executables.
485 Currently used for FEATURE(`local_lmtp') and
487 QPAGE_MAILER_FLAGS [mDFMs] The flags used by the qpage mailer.
488 QPAGE_MAILER_PATH [/usr/local/bin/qpage] The program used to deliver
490 QPAGE_MAILER_ARGS [qpage -l0 -m -P$u] The arguments passed
491 to deliver qpage mail.
492 QPAGE_MAILER_MAX [4096] If set, the maximum size message that
493 will be accepted by the qpage mailer.
494 QPAGE_MAILER_QGRP [undefined] The queue group for the qpage mailer.
495 LOCAL_PROG_QGRP [undefined] The queue group for the prog mailer.
497 Note: to tweak Name_MAILER_FLAGS use the macro MODIFY_MAILER_FLAGS:
498 MODIFY_MAILER_FLAGS(`Name', `change') where Name is the first part
499 of the macro Name_MAILER_FLAGS (note: that means Name is entirely in
500 upper case) and change can be: flags that should be used directly
501 (thus overriding the default value), or if it starts with `+' (`-')
502 then those flags are added to (removed from) the default value.
505 MODIFY_MAILER_FLAGS(`LOCAL', `+e')
507 will add the flag `e' to LOCAL_MAILER_FLAGS. Notice: there are
508 several smtp mailers all of which are manipulated individually.
509 See the section MAILERS for the available mailer names.
510 WARNING: The FEATUREs local_lmtp and local_procmail set LOCAL_MAILER_FLAGS
511 unconditionally, i.e., without respecting any definitions in an
519 You will probably want to collect domain-dependent defines into one
520 file, referenced by the DOMAIN macro. For example, the Berkeley
521 domain file includes definitions for several internal distinguished
524 UUCP_RELAY The host that will accept UUCP-addressed email.
525 If not defined, all UUCP sites must be directly
527 BITNET_RELAY The host that will accept BITNET-addressed email.
528 If not defined, the .BITNET pseudo-domain won't work.
529 DECNET_RELAY The host that will accept DECNET-addressed email.
530 If not defined, the .DECNET pseudo-domain and addresses
531 of the form node::user will not work.
532 FAX_RELAY The host that will accept mail to the .FAX pseudo-domain.
533 The "fax" mailer overrides this value.
534 LOCAL_RELAY The site that will handle unqualified names -- that
535 is, names without an @domain extension.
536 Normally MAIL_HUB is preferred for this function.
537 LOCAL_RELAY is mostly useful in conjunction with
538 FEATURE(`stickyhost') -- see the discussion of
539 stickyhost below. If not set, they are assumed to
540 belong on this machine. This allows you to have a
541 central site to store a company- or department-wide
542 alias database. This only works at small sites,
543 and only with some user agents.
544 LUSER_RELAY The site that will handle lusers -- that is, apparently
545 local names that aren't local accounts or aliases. To
546 specify a local user instead of a site, set this to
549 Any of these can be either ``mailer:hostname'' (in which case the
550 mailer is the internal mailer name, such as ``uucp-new'' and the hostname
551 is the name of the host as appropriate for that mailer) or just a
552 ``hostname'', in which case a default mailer type (usually ``relay'',
553 a variant on SMTP) is used. WARNING: if you have a wildcard MX
554 record matching your domain, you probably want to define these to
555 have a trailing dot so that you won't get the mail diverted back
558 The domain file can also be used to define a domain name, if needed
559 (using "DD<domain>") and set certain site-wide features. If all hosts
560 at your site masquerade behind one email name, you could also use
563 You do not have to define a domain -- in particular, if you are a
564 single machine sitting off somewhere, it is probably more work than
565 it's worth. This is just a mechanism for combining "domain dependent
566 knowledge" into one place.
573 There are fewer mailers supported in this version than the previous
574 version, owing mostly to a simpler world. As a general rule, put the
575 MAILER definitions last in your .mc file.
577 local The local and prog mailers. You will almost always
578 need these; the only exception is if you relay ALL
579 your mail to another site. This mailer is included
582 smtp The Simple Mail Transport Protocol mailer. This does
583 not hide hosts behind a gateway or another other
584 such hack; it assumes a world where everyone is
585 running the name server. This file actually defines
586 five mailers: "smtp" for regular (old-style) SMTP to
587 other servers, "esmtp" for extended SMTP to other
588 servers, "smtp8" to do SMTP to other servers without
589 converting 8-bit data to MIME (essentially, this is
590 your statement that you know the other end is 8-bit
591 clean even if it doesn't say so), "dsmtp" to do on
592 demand delivery, and "relay" for transmission to the
593 RELAY_HOST, LUSER_RELAY, or MAIL_HUB.
595 uucp The UNIX-to-UNIX Copy Program mailer. Actually, this
596 defines two mailers, "uucp-old" (a.k.a. "uucp") and
597 "uucp-new" (a.k.a. "suucp"). The latter is for when you
598 know that the UUCP mailer at the other end can handle
599 multiple recipients in one transfer. If the smtp mailer
600 is included in your configuration, two other mailers
601 ("uucp-dom" and "uucp-uudom") are also defined [warning: you
602 MUST specify MAILER(`smtp') before MAILER(`uucp')]. When you
603 include the uucp mailer, sendmail looks for all names in
604 class {U} and sends them to the uucp-old mailer; all
605 names in class {Y} are sent to uucp-new; and all
606 names in class {Z} are sent to uucp-uudom. Note that
607 this is a function of what version of rmail runs on
608 the receiving end, and hence may be out of your control.
609 See the section below describing UUCP mailers in more
612 usenet Usenet (network news) delivery. If this is specified,
613 an extra rule is added to ruleset 0 that forwards all
614 local email for users named ``group.usenet'' to the
615 ``inews'' program. Note that this works for all groups,
616 and may be considered a security problem.
618 fax Facsimile transmission. This is experimental and based
619 on Sam Leffler's HylaFAX software. For more information,
620 see http://www.hylafax.org/.
622 pop Post Office Protocol.
624 procmail An interface to procmail (does not come with sendmail).
625 This is designed to be used in mailertables. For example,
626 a common question is "how do I forward all mail for a given
627 domain to a single person?". If you have this mailer
628 defined, you could set up a mailertable reading:
630 host.com procmail:/etc/procmailrcs/host.com
632 with the file /etc/procmailrcs/host.com reading:
634 :0 # forward mail for host.com
635 ! -oi -f $1 person@other.host
637 This would arrange for (anything)@host.com to be sent
638 to person@other.host. In a procmail script, $1 is the
639 name of the sender and $2 is the name of the recipient.
640 If you use this with FEATURE(`local_procmail'), the FEATURE
641 should be listed first.
643 Of course there are other ways to solve this particular
644 problem, e.g., a catch-all entry in a virtusertable.
646 mail11 The DECnet mail11 mailer, useful only if you have the mail11
647 program from gatekeeper.dec.com:/pub/DEC/gwtools (and
648 DECnet, of course). This is for Phase IV DECnet support;
649 if you have Phase V at your site you may have additional
652 phquery The phquery program. This is somewhat counterintuitively
653 referenced as the "ph" mailer internally. It can be used
654 to do CCSO name server lookups. The phquery program, which
655 this mailer uses, is distributed with the ph client.
657 cyrus The cyrus and cyrusbb mailers. The cyrus mailer delivers to
658 a local cyrus user. this mailer can make use of the
659 "user+detail@local.host" syntax (see
660 FEATURE(`preserve_local_plus_detail')); it will deliver the
661 mail to the user's "detail" mailbox if the mailbox's ACL
662 permits. The cyrusbb mailer delivers to a system-wide
663 cyrus mailbox if the mailbox's ACL permits. The cyrus
664 mailer must be defined after the local mailer.
666 cyrusv2 The mailer for Cyrus v2.x. The cyrusv2 mailer delivers to
667 local cyrus users via LMTP. This mailer can make use of the
668 "user+detail@local.host" syntax (see
669 FEATURE(`preserve_local_plus_detail')); it will deliver the
670 mail to the user's "detail" mailbox if the mailbox's ACL
671 permits. The cyrusv2 mailer must be defined after the
674 qpage A mailer for QuickPage, a pager interface. See
675 http://www.qpage.org/ for further information.
677 The local mailer accepts addresses of the form "user+detail", where
678 the "+detail" is not used for mailbox matching but is available
679 to certain local mail programs (in particular, see
680 FEATURE(`local_procmail')). For example, "eric", "eric+sendmail", and
681 "eric+sww" all indicate the same user, but additional arguments <null>,
682 "sendmail", and "sww" may be provided for use in sorting mail.
689 Special features can be requested using the "FEATURE" macro. For
690 example, the .mc line:
692 FEATURE(`use_cw_file')
694 tells sendmail that you want to have it read an /etc/mail/local-host-names
695 file to get values for class {w}. A FEATURE may contain up to 9
696 optional parameters -- for example:
698 FEATURE(`mailertable', `dbm /usr/lib/mailertable')
700 The default database map type for the table features can be set with
702 define(`DATABASE_MAP_TYPE', `dbm')
704 which would set it to use ndbm databases. The default is the Berkeley DB
705 hash database format. Note that you must still declare a database map type
706 if you specify an argument to a FEATURE. DATABASE_MAP_TYPE is only used
707 if no argument is given for the FEATURE. It must be specified before any
708 feature that uses a map.
710 Also, features which can take a map definition as an argument can also take
711 the special keyword `LDAP'. If that keyword is used, the map will use the
712 LDAP definition described in the ``USING LDAP FOR ALIASES, MAPS, AND
713 CLASSES'' section below.
715 Available features are:
717 use_cw_file Read the file /etc/mail/local-host-names file to get
718 alternate names for this host. This might be used if you
719 were on a host that MXed for a dynamic set of other hosts.
720 If the set is static, just including the line "Cw<name1>
721 <name2> ..." (where the names are fully qualified domain
722 names) is probably superior. The actual filename can be
723 overridden by redefining confCW_FILE.
725 use_ct_file Read the file /etc/mail/trusted-users file to get the
726 names of users that will be ``trusted'', that is, able to
727 set their envelope from address using -f without generating
728 a warning message. The actual filename can be overridden
729 by redefining confCT_FILE.
731 redirect Reject all mail addressed to "address.REDIRECT" with
732 a ``551 User has moved; please try <address>'' message.
733 If this is set, you can alias people who have left
734 to their new address with ".REDIRECT" appended.
736 nouucp Don't route UUCP addresses. This feature takes one
738 `reject': reject addresses which have "!" in the local
739 part unless it originates from a system
740 that is allowed to relay.
741 `nospecial': don't do anything special with "!".
742 Warnings: 1. See the notice in the anti-spam section.
743 2. don't remove "!" from OperatorChars if `reject' is
746 nocanonify Don't pass addresses to $[ ... $] for canonification
747 by default, i.e., host/domain names are considered canonical,
748 except for unqualified names, which must not be used in this
749 mode (violation of the standard). It can be changed by
750 setting the DaemonPortOptions modifiers (M=). That is,
751 FEATURE(`nocanonify') will be overridden by setting the
752 'c' flag. Conversely, if FEATURE(`nocanonify') is not used,
753 it can be emulated by setting the 'C' flag
754 (DaemonPortOptions=Modifiers=C). This would generally only
755 be used by sites that only act as mail gateways or which have
756 user agents that do full canonification themselves. You may
758 "define(`confBIND_OPTS', `-DNSRCH -DEFNAMES')" to turn off
759 the usual resolver options that do a similar thing.
761 An exception list for FEATURE(`nocanonify') can be
762 specified with CANONIFY_DOMAIN or CANONIFY_DOMAIN_FILE,
763 i.e., a list of domains which are nevertheless passed to
764 $[ ... $] for canonification. This is useful to turn on
765 canonification for local domains, e.g., use
766 CANONIFY_DOMAIN(`my.domain my') to canonify addresses
767 which end in "my.domain" or "my".
768 Another way to require canonification in the local
769 domain is CANONIFY_DOMAIN(`$=m').
771 A trailing dot is added to addresses with more than
772 one component in it such that other features which
773 expect a trailing dot (e.g., virtusertable) will
776 If `canonify_hosts' is specified as parameter, i.e.,
777 FEATURE(`nocanonify', `canonify_hosts'), then
778 addresses which have only a hostname, e.g.,
779 <user@host>, will be canonified (and hopefully fully
782 stickyhost This feature is sometimes used with LOCAL_RELAY,
783 although it can be used for a different effect with
786 When used without MAIL_HUB, email sent to
787 "user@local.host" are marked as "sticky" -- that
788 is, the local addresses aren't matched against UDB,
789 don't go through ruleset 5, and are not forwarded to
790 the LOCAL_RELAY (if defined).
792 With MAIL_HUB, mail addressed to "user@local.host"
793 is forwarded to the mail hub, with the envelope
794 address still remaining "user@local.host".
795 Without stickyhost, the envelope would be changed
796 to "user@mail_hub", in order to protect against
799 mailertable Include a "mailer table" which can be used to override
800 routing for particular domains (which are not in class {w},
801 i.e. local host names). The argument of the FEATURE may be
802 the key definition. If none is specified, the definition
805 hash /etc/mail/mailertable
807 Keys in this database are fully qualified domain names
808 or partial domains preceded by a dot -- for example,
809 "vangogh.CS.Berkeley.EDU" or ".CS.Berkeley.EDU". As a
810 special case of the latter, "." matches any domain not
811 covered by other keys. Values must be of the form:
813 where "mailer" is the internal mailer name, and "domain"
814 is where to send the message. These maps are not
815 reflected into the message header. As a special case,
818 will forward to the indicated user using the local mailer,
820 will forward to the original user in the e-mail address
821 using the local mailer, and
823 error:D.S.N:code message
824 will give an error message with the indicated SMTP reply
825 code and message, where D.S.N is an RFC 1893 compliant
828 domaintable Include a "domain table" which can be used to provide
829 domain name mapping. Use of this should really be
830 limited to your own domains. It may be useful if you
831 change names (e.g., your company changes names from
832 oldname.com to newname.com). The argument of the
833 FEATURE may be the key definition. If none is specified,
834 the definition used is:
836 hash /etc/mail/domaintable
838 The key in this table is the domain name; the value is
839 the new (fully qualified) domain. Anything in the
840 domaintable is reflected into headers; that is, this
841 is done in ruleset 3.
843 bitdomain Look up bitnet hosts in a table to try to turn them into
844 internet addresses. The table can be built using the
845 bitdomain program contributed by John Gardiner Myers.
846 The argument of the FEATURE may be the key definition; if
847 none is specified, the definition used is:
849 hash /etc/mail/bitdomain
851 Keys are the bitnet hostname; values are the corresponding
854 uucpdomain Similar feature for UUCP hosts. The default map definition
857 hash /etc/mail/uudomain
859 At the moment there is no automagic tool to build this
863 Include the local host domain even on locally delivered
864 mail. Normally it is not added on unqualified names.
865 However, if you use a shared message store but do not use
866 the same user name space everywhere, you may need the host
867 name on local names. An optional argument specifies
868 another domain to be added than the local.
870 allmasquerade If masquerading is enabled (using MASQUERADE_AS), this
871 feature will cause recipient addresses to also masquerade
872 as being from the masquerade host. Normally they get
873 the local hostname. Although this may be right for
874 ordinary users, it can break local aliases. For example,
875 if you send to "localalias", the originating sendmail will
876 find that alias and send to all members, but send the
877 message with "To: localalias@masqueradehost". Since that
878 alias likely does not exist, replies will fail. Use this
879 feature ONLY if you can guarantee that the ENTIRE
880 namespace on your masquerade host supersets all the
884 Normally, any hosts listed in class {w} are masqueraded. If
885 this feature is given, only the hosts listed in class {M} (see
886 below: MASQUERADE_DOMAIN) are masqueraded. This is useful
887 if you have several domains with disjoint namespaces hosted
890 masquerade_entire_domain
891 If masquerading is enabled (using MASQUERADE_AS) and
892 MASQUERADE_DOMAIN (see below) is set, this feature will
893 cause addresses to be rewritten such that the masquerading
894 domains are actually entire domains to be hidden. All
895 hosts within the masquerading domains will be rewritten
896 to the masquerade name (used in MASQUERADE_AS). For example,
899 MASQUERADE_AS(`masq.com')
900 MASQUERADE_DOMAIN(`foo.org')
901 MASQUERADE_DOMAIN(`bar.com')
903 then *foo.org and *bar.com are converted to masq.com. Without
904 this feature, only foo.org and bar.com are masqueraded.
906 NOTE: only domains within your jurisdiction and
907 current hierarchy should be masqueraded using this.
910 This feature prevents the local mailer from masquerading even
911 if MASQUERADE_AS is used. MASQUERADE_AS will only have effect
912 on addresses of mail going outside the local domain.
915 If masquerading is enabled (using MASQUERADE_AS) or the
916 genericstable is in use, this feature will cause envelope
917 addresses to also masquerade as being from the masquerade
918 host. Normally only the header addresses are masqueraded.
920 genericstable This feature will cause unqualified addresses (i.e., without
921 a domain) and addresses with a domain listed in class {G}
922 to be looked up in a map and turned into another ("generic")
923 form, which can change both the domain name and the user name.
924 Notice: if you use an MSP (as it is default starting with
925 8.12), the MTA will only receive qualified addresses from the
926 MSP (as required by the RFCs). Hence you need to add your
927 domain to class {G}. This feature is similar to the userdb
928 functionality. The same types of addresses as for
929 masquerading are looked up, i.e., only header sender
930 addresses unless the allmasquerade and/or masquerade_envelope
931 features are given. Qualified addresses must have the domain
932 part in class {G}; entries can be added to this class by the
933 macros GENERICS_DOMAIN or GENERICS_DOMAIN_FILE (analogously
934 to MASQUERADE_DOMAIN and MASQUERADE_DOMAIN_FILE, see below).
936 The argument of FEATURE(`genericstable') may be the map
937 definition; the default map definition is:
939 hash /etc/mail/genericstable
941 The key for this table is either the full address, the domain
942 (with a leading @; the localpart is passed as first argument)
943 or the unqualified username (tried in the order mentioned);
944 the value is the new user address. If the new user address
945 does not include a domain, it will be qualified in the standard
946 manner, i.e., using $j or the masquerade name. Note that the
947 address being looked up must be fully qualified. For local
948 mail, it is necessary to use FEATURE(`always_add_domain')
949 for the addresses to be qualified.
950 The "+detail" of an address is passed as %1, so entries like
952 old+*@foo.org new+%1@example.com
953 gen+*@foo.org %1@example.com
955 and other forms are possible.
957 generics_entire_domain
958 If the genericstable is enabled and GENERICS_DOMAIN or
959 GENERICS_DOMAIN_FILE is used, this feature will cause
960 addresses to be searched in the map if their domain
961 parts are subdomains of elements in class {G}.
963 virtusertable A domain-specific form of aliasing, allowing multiple
964 virtual domains to be hosted on one machine. For example,
965 if the virtuser table contains:
967 info@foo.com foo-info
968 info@bar.com bar-info
969 joe@bar.com error:nouser 550 No such user here
970 jax@bar.com error:5.7.0:550 Address invalid
971 @baz.org jane@example.net
973 then mail addressed to info@foo.com will be sent to the
974 address foo-info, mail addressed to info@bar.com will be
975 delivered to bar-info, and mail addressed to anyone at baz.org
976 will be sent to jane@example.net, mail to joe@bar.com will
977 be rejected with the specified error message, and mail to
978 jax@bar.com will also have a RFC 1893 compliant error code
981 The username from the original address is passed
984 @foo.org %1@example.com
986 meaning someone@foo.org will be sent to someone@example.com.
987 Additionally, if the local part consists of "user+detail"
988 then "detail" is passed as %2 and "+detail" is passed as %3
989 when a match against user+* is attempted, so entries like
991 old+*@foo.org new+%2@example.com
992 gen+*@foo.org %2@example.com
993 +*@foo.org %1%3@example.com
994 X++@foo.org Z%3@example.com
997 and other forms are possible. Note: to preserve "+detail"
998 for a default case (@domain) %1%3 must be used as RHS.
999 There are two wildcards after "+": "+" matches only a non-empty
1000 detail, "*" matches also empty details, e.g., user+@foo.org
1001 matches +*@foo.org but not ++@foo.org. This can be used
1002 to ensure that the parameters %2 and %3 are not empty.
1004 All the host names on the left hand side (foo.com, bar.com,
1005 and baz.org) must be in class {w} or class {VirtHost}. The
1006 latter can be defined by the macros VIRTUSER_DOMAIN or
1007 VIRTUSER_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1008 MASQUERADE_DOMAIN_FILE, see below). If VIRTUSER_DOMAIN or
1009 VIRTUSER_DOMAIN_FILE is used, then the entries of class
1010 {VirtHost} are added to class {R}, i.e., relaying is allowed
1011 to (and from) those domains. The default map definition is:
1013 hash /etc/mail/virtusertable
1015 A new definition can be specified as the second argument of
1016 the FEATURE macro, such as
1018 FEATURE(`virtusertable', `dbm /etc/mail/virtusers')
1020 virtuser_entire_domain
1021 If the virtusertable is enabled and VIRTUSER_DOMAIN or
1022 VIRTUSER_DOMAIN_FILE is used, this feature will cause
1023 addresses to be searched in the map if their domain
1024 parts are subdomains of elements in class {VirtHost}.
1026 ldap_routing Implement LDAP-based e-mail recipient routing according to
1027 the Internet Draft draft-lachman-laser-ldap-mail-routing-01.
1028 This provides a method to re-route addresses with a
1029 domain portion in class {LDAPRoute} to either a
1030 different mail host or a different address. Hosts can
1031 be added to this class using LDAPROUTE_DOMAIN and
1032 LDAPROUTE_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1033 MASQUERADE_DOMAIN_FILE, see below).
1035 See the LDAP ROUTING section below for more information.
1037 nullclient This is a special case -- it creates a configuration file
1038 containing nothing but support for forwarding all mail to a
1039 central hub via a local SMTP-based network. The argument
1040 is the name of that hub.
1042 The only other feature that should be used in conjunction
1043 with this one is FEATURE(`nocanonify'). No mailers
1044 should be defined. No aliasing or forwarding is done.
1046 local_lmtp Use an LMTP capable local mailer. The argument to this
1047 feature is the pathname of an LMTP capable mailer. By
1048 default, mail.local is used. This is expected to be the
1049 mail.local which came with the 8.9 distribution which is
1050 LMTP capable. The path to mail.local is set by the
1051 confEBINDIR m4 variable -- making the default
1052 LOCAL_MAILER_PATH /usr/libexec/mail.local.
1053 If a different LMTP capable mailer is used, its pathname
1054 can be specified as second parameter and the arguments
1055 passed to it (A=) as third parameter, e.g.,
1057 FEATURE(`local_lmtp', `/usr/local/bin/lmtp', `lmtp')
1059 WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
1060 i.e., without respecting any definitions in an OSTYPE setting.
1062 local_procmail Use procmail or another delivery agent as the local mailer.
1063 The argument to this feature is the pathname of the
1064 delivery agent, which defaults to PROCMAIL_MAILER_PATH.
1065 Note that this does NOT use PROCMAIL_MAILER_FLAGS or
1066 PROCMAIL_MAILER_ARGS for the local mailer; tweak
1067 LOCAL_MAILER_FLAGS and LOCAL_MAILER_ARGS instead, or
1068 specify the appropriate parameters. When procmail is used,
1069 the local mailer can make use of the
1070 "user+indicator@local.host" syntax; normally the +indicator
1071 is just tossed, but by default it is passed as the -a
1072 argument to procmail.
1074 This feature can take up to three arguments:
1076 1. Path to the mailer program
1077 [default: /usr/local/bin/procmail]
1078 2. Argument vector including name of the program
1079 [default: procmail -Y -a $h -d $u]
1080 3. Flags for the mailer [default: SPfhn9]
1082 Empty arguments cause the defaults to be taken.
1083 Note that if you are on a system with a broken
1084 setreuid() call, you may need to add -f $f to the procmail
1085 argument vector to pass the proper sender to procmail.
1087 For example, this allows it to use the maildrop
1088 (http://www.flounder.net/~mrsam/maildrop/) mailer instead
1091 FEATURE(`local_procmail', `/usr/local/bin/maildrop',
1096 FEATURE(`local_procmail', `/usr/local/bin/scanmails')
1098 WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
1099 i.e., without respecting any definitions in an OSTYPE setting.
1101 bestmx_is_local Accept mail as though locally addressed for any host that
1102 lists us as the best possible MX record. This generates
1103 additional DNS traffic, but should be OK for low to
1104 medium traffic hosts. The argument may be a set of
1105 domains, which will limit the feature to only apply to
1106 these domains -- this will reduce unnecessary DNS
1107 traffic. THIS FEATURE IS FUNDAMENTALLY INCOMPATIBLE WITH
1108 WILDCARD MX RECORDS!!! If you have a wildcard MX record
1109 that matches your domain, you cannot use this feature.
1111 smrsh Use the SendMail Restricted SHell (smrsh) provided
1112 with the distribution instead of /bin/sh for mailing
1113 to programs. This improves the ability of the local
1114 system administrator to control what gets run via
1115 e-mail. If an argument is provided it is used as the
1116 pathname to smrsh; otherwise, the path defined by
1117 confEBINDIR is used for the smrsh binary -- by default,
1118 /usr/libexec/smrsh is assumed.
1121 By default, the sendmail configuration files do not permit
1122 mail relaying (that is, accepting mail from outside your
1123 local host (class {w}) and sending it to another host than
1124 your local host). This option sets your site to allow
1125 mail relaying from any site to any site. In almost all
1126 cases, it is better to control relaying more carefully
1127 with the access map, class {R}, or authentication. Domains
1128 can be added to class {R} by the macros RELAY_DOMAIN or
1129 RELAY_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1130 MASQUERADE_DOMAIN_FILE, see below).
1133 This option allows any host in your domain as defined by
1134 class {m} to use your server for relaying. Notice: make
1135 sure that your domain is not just a top level domain,
1136 e.g., com. This can happen if you give your host a name
1137 like example.com instead of host.example.com.
1140 By default, names that are listed as RELAY in the access
1141 db and class {R} are treated as domain names, not host names.
1142 For example, if you specify ``foo.com'', then mail to or
1143 from foo.com, abc.foo.com, or a.very.deep.domain.foo.com
1144 will all be accepted for relaying. This feature changes
1145 the behaviour to lookup individual host names only.
1148 Turns on the ability to allow relaying based on the MX
1149 records of the host portion of an incoming recipient; that
1150 is, if an MX record for host foo.com points to your site,
1151 you will accept and relay mail addressed to foo.com. See
1152 description below for more information before using this
1153 feature. Also, see the KNOWNBUGS entry regarding bestmx
1156 FEATURE(`relay_based_on_MX') does not necessarily allow
1157 routing of these messages which you expect to be allowed,
1158 if route address syntax (or %-hack syntax) is used. If
1159 this is a problem, add entries to the access-table or use
1160 FEATURE(`loose_relay_check').
1163 Allows relaying if the mail sender is listed as RELAY in
1164 the access map. If an optional argument `domain' (this
1165 is the literal word `domain', not a placeholder) is given,
1166 relaying can be allowed just based on the domain portion
1167 of the sender address. This feature should only be used if
1168 absolutely necessary as the sender address can be easily
1169 forged. Use of this feature requires the "From:" tag to
1170 be used for the key in the access map; see the discussion
1171 of tags and FEATURE(`relay_mail_from') in the section on
1172 anti-spam configuration control.
1175 Allows relaying if the domain portion of the mail sender
1176 is a local host. This should only be used if absolutely
1177 necessary as it opens a window for spammers. Specifically,
1178 they can send mail to your mail server that claims to be
1179 from your domain (either directly or via a routed address),
1180 and you will go ahead and relay it out to arbitrary hosts
1183 accept_unqualified_senders
1184 Normally, MAIL FROM: commands in the SMTP session will be
1185 refused if the connection is a network connection and the
1186 sender address does not include a domain name. If your
1187 setup sends local mail unqualified (i.e., MAIL FROM:<joe>),
1188 you will need to use this feature to accept unqualified
1189 sender addresses. Setting the DaemonPortOptions modifier
1190 'u' overrides the default behavior, i.e., unqualified
1191 addresses are accepted even without this FEATURE.
1192 If this FEATURE is not used, the DaemonPortOptions modifier
1193 'f' can be used to enforce fully qualified addresses.
1195 accept_unresolvable_domains
1196 Normally, MAIL FROM: commands in the SMTP session will be
1197 refused if the host part of the argument to MAIL FROM:
1198 cannot be located in the host name service (e.g., an A or
1199 MX record in DNS). If you are inside a firewall that has
1200 only a limited view of the Internet host name space, this
1201 could cause problems. In this case you probably want to
1202 use this feature to accept all domains on input, even if
1203 they are unresolvable.
1205 access_db Turns on the access database feature. The access db gives
1206 you the ability to allow or refuse to accept mail from
1207 specified domains for administrative reasons. Moreover,
1208 it can control the behavior of sendmail in various situations.
1209 By default, the access database specification is:
1211 hash -T<TMPF> /etc/mail/access
1213 See the anti-spam configuration control section for further
1214 important information about this feature. Notice:
1215 "-T<TMPF>" is meant literal, do not replace it by anything.
1217 blacklist_recipients
1218 Turns on the ability to block incoming mail for certain
1219 recipient usernames, hostnames, or addresses. For
1220 example, you can block incoming mail to user nobody,
1221 host foo.mydomain.com, or guest@bar.mydomain.com.
1222 These specifications are put in the access db as
1223 described in the anti-spam configuration control section
1224 later in this document.
1226 delay_checks The rulesets check_mail and check_relay will not be called
1227 when a client connects or issues a MAIL command, respectively.
1228 Instead, those rulesets will be called by the check_rcpt
1229 ruleset; they will be skipped under certain circumstances.
1230 See "Delay all checks" in the anti-spam configuration control
1231 section. Note: this feature is incompatible to the versions
1234 use_client_ptr If this feature is enabled then check_relay will override
1235 its first argument with $&{client_ptr}. This is useful for
1236 rejections based on the unverified hostname of client,
1237 which turns on the same behavior as in earlier sendmail
1238 versions when delay_checks was not in use. See doc/op/op.*
1239 about check_relay, {client_name}, and {client_ptr}.
1241 dnsbl Turns on rejection, discarding, or quarantining of hosts
1242 found in a DNS based list. The first argument is used as
1243 the domain in which blocked hosts are listed. A second
1244 argument can be used to change the default error message,
1245 or select one of the operations `discard' and `quarantine'.
1246 Without that second argument, the error message will be
1248 Rejected: IP-ADDRESS listed at SERVER
1250 where IP-ADDRESS and SERVER are replaced by the appropriate
1251 information. By default, temporary lookup failures are
1252 ignored. This behavior can be changed by specifying a
1253 third argument, which must be either `t' or a full error
1254 message. See the anti-spam configuration control section for
1255 an example. The dnsbl feature can be included several times
1256 to query different DNS based rejection lists. See also
1257 enhdnsbl for an enhanced version.
1259 Set the DNSBL_MAP mc option to change the default map
1260 definition from `host'. Set the DNSBL_MAP_OPT mc option
1261 to add additional options to the map specification used.
1263 Some DNS based rejection lists cause failures if asked
1264 for AAAA records. If your sendmail version is compiled
1265 with IPv6 support (NETINET6) and you experience this
1268 define(`DNSBL_MAP', `dns -R A')
1270 before the first use of this feature. Alternatively you
1271 can use enhdnsbl instead (see below). Moreover, this
1272 statement can be used to reduce the number of DNS retries,
1275 define(`DNSBL_MAP', `dns -R A -r2')
1277 See below (EDNSBL_TO) for an explanation.
1279 enhdnsbl Enhanced version of dnsbl (see above). Further arguments
1280 (up to 5) can be used to specify specific return values
1281 from lookups. Temporary lookup failures are ignored unless
1282 a third argument is given, which must be either `t' or a full
1283 error message. By default, any successful lookup will
1284 generate an error. Otherwise the result of the lookup is
1285 compared with the supplied argument(s), and only if a match
1286 occurs an error is generated. For example,
1288 FEATURE(`enhdnsbl', `dnsbl.example.com', `', `t', `127.0.0.2.')
1290 will reject the e-mail if the lookup returns the value
1291 ``127.0.0.2.'', or generate a 451 response if the lookup
1292 temporarily failed. The arguments can contain metasymbols
1293 as they are allowed in the LHS of rules. As the example
1294 shows, the default values are also used if an empty argument,
1295 i.e., `', is specified. This feature requires that sendmail
1296 has been compiled with the flag DNSMAP (see sendmail/README).
1298 Set the EDNSBL_TO mc option to change the DNS retry count
1299 from the default value of 5, this can be very useful when
1300 a DNS server is not responding, which in turn may cause
1301 clients to time out (an entry stating
1303 did not issue MAIL/EXPN/VRFY/ETRN
1307 ratecontrol Enable simple ruleset to do connection rate control
1308 checking. This requires entries in access_db of the form
1310 ClientRate:IP.ADD.RE.SS LIMIT
1312 The RHS specifies the maximum number of connections
1313 (an integer number) over the time interval defined
1314 by ConnectionRateWindowSize, where 0 means unlimited.
1316 Take the following example:
1318 ClientRate:10.1.2.3 4
1319 ClientRate:127.0.0.1 0
1322 10.1.2.3 can only make up to 4 connections, the
1323 general limit it 10, and 127.0.0.1 can make an unlimited
1324 number of connections per ConnectionRateWindowSize.
1326 See also CONNECTION CONTROL.
1328 conncontrol Enable a simple check of the number of incoming SMTP
1329 connections. This requires entries in access_db of the
1332 ClientConn:IP.ADD.RE.SS LIMIT
1334 The RHS specifies the maximum number of open connections
1335 (an integer number).
1337 Take the following example:
1339 ClientConn:10.1.2.3 4
1340 ClientConn:127.0.0.1 0
1343 10.1.2.3 can only have up to 4 open connections, the
1344 general limit it 10, and 127.0.0.1 does not have any
1347 See also CONNECTION CONTROL.
1349 mtamark Experimental support for "Marking Mail Transfer Agents in
1350 Reverse DNS with TXT RRs" (MTAMark), see
1351 draft-stumpf-dns-mtamark-01. Optional arguments are:
1353 1. Error message, default:
1355 550 Rejected: $&{client_addr} not listed as MTA
1357 2. Temporary lookup failures are ignored unless a second
1358 argument is given, which must be either `t' or a full
1361 3. Lookup prefix, default: _perm._smtp._srv. This should
1362 not be changed unless the draft changes it.
1366 FEATURE(`mtamark', `', `t')
1368 lookupdotdomain Look up also .domain in the access map. This allows to
1369 match only subdomains. It does not work well with
1370 FEATURE(`relay_hosts_only'), because most lookups for
1371 subdomains are suppressed by the latter feature.
1374 Normally, if % addressing is used for a recipient, e.g.
1375 user%site@othersite, and othersite is in class {R}, the
1376 check_rcpt ruleset will strip @othersite and recheck
1377 user@site for relaying. This feature changes that
1378 behavior. It should not be needed for most installations.
1380 authinfo Provide a separate map for client side authentication
1381 information. See SMTP AUTHENTICATION for details.
1382 By default, the authinfo database specification is:
1384 hash /etc/mail/authinfo
1387 Preserve the name of the recipient host if LUSER_RELAY is
1388 used. Without this option, the domain part of the
1389 recipient address will be replaced by the host specified as
1390 LUSER_RELAY. This feature only works if the hostname is
1391 passed to the mailer (see mailer triple in op.me). Note
1392 that in the default configuration the local mailer does not
1393 receive the hostname, i.e., the mailer triple has an empty
1396 preserve_local_plus_detail
1397 Preserve the +detail portion of the address when passing
1398 address to local delivery agent. Disables alias and
1399 .forward +detail stripping (e.g., given user+detail, only
1400 that address will be looked up in the alias file; user+* and
1401 user will not be looked up). Only use if the local
1402 delivery agent in use supports +detail addressing.
1404 compat_check Enable ruleset check_compat to look up pairs of addresses
1405 with the Compat: tag -- Compat:sender<@>recipient -- in the
1406 access map. Valid values for the RHS include
1407 DISCARD silently discard recipient
1408 TEMP: return a temporary error
1409 ERROR: return a permanent error
1410 In the last two cases, a 4xy/5xy SMTP reply code should
1413 no_default_msa Don't generate the default MSA daemon, i.e.,
1414 DAEMON_OPTIONS(`Port=587,Name=MSA,M=E')
1415 To define a MSA daemon with other parameters, use this
1416 FEATURE and introduce new settings via DAEMON_OPTIONS().
1418 msp Defines config file for Message Submission Program.
1419 See sendmail/SECURITY for details and cf/cf/submit.mc how
1420 to use it. An optional argument can be used to override
1421 the default of `[localhost]' to use as host to send all
1422 e-mails to. Note that MX records will be used if the
1423 specified hostname is not in square brackets (e.g.,
1424 [hostname]). If `MSA' is specified as second argument then
1425 port 587 is used to contact the server. Example:
1427 FEATURE(`msp', `', `MSA')
1429 Some more hints about possible changes can be found below
1430 in the section MESSAGE SUBMISSION PROGRAM.
1432 Note: Due to many problems, submit.mc uses
1434 FEATURE(`msp', `[127.0.0.1]')
1436 by default. If you have a machine with IPv6 only,
1439 FEATURE(`msp', `[IPv6:::1]')
1441 If you want to continue using '[localhost]', (the behavior
1446 queuegroup A simple example how to select a queue group based
1447 on the full e-mail address or the domain of the
1448 recipient. Selection is done via entries in the
1449 access map using the tag QGRP:, for example:
1451 QGRP:example.com main
1452 QGRP:friend@some.org others
1453 QGRP:my.domain local
1455 where "main", "others", and "local" are names of
1456 queue groups. If an argument is specified, it is used
1457 as default queue group.
1459 Note: please read the warning in doc/op/op.me about
1460 queue groups and possible queue manipulations.
1462 greet_pause Adds the greet_pause ruleset which enables open proxy
1463 and SMTP slamming protection. The feature can take an
1464 argument specifying the milliseconds to wait:
1466 FEATURE(`greet_pause', `5000') dnl 5 seconds
1468 If FEATURE(`access_db') is enabled, an access database
1469 lookup with the GreetPause tag is done using client
1470 hostname, domain, IP address, or subnet to determine the
1473 GreetPause:my.domain 0
1474 GreetPause:example.com 5000
1475 GreetPause:10.1.2 2000
1476 GreetPause:127.0.0.1 0
1478 When using FEATURE(`access_db'), the optional
1479 FEATURE(`greet_pause') argument becomes the default if
1480 nothing is found in the access database. A ruleset called
1481 Local_greet_pause can be used for local modifications, e.g.,
1485 R$* $: $&{daemon_flags}
1488 block_bad_helo Reject messages from SMTP clients which provide a HELO/EHLO
1489 argument which is either unqualified, or is one of our own
1490 names (i.e., the server name instead of the client name).
1491 This check is performed at RCPT stage and disabled for the
1493 - authenticated sessions,
1494 - connections from IP addresses in class $={R}.
1495 Currently access_db lookups can not be used to
1496 (selectively) disable this test, moreover,
1497 FEATURE(`delay_checks')
1500 require_rdns Reject mail from connecting SMTP clients without proper
1501 rDNS (reverse DNS), functional gethostbyaddr() resolution.
1502 Note: this feature will cause false positives, i.e., there
1503 are legitimate MTAs that do not have proper DNS entries.
1504 Rejecting mails from those MTAs is a local policy decision.
1506 The basic policy is to reject message with a 5xx error if
1507 the IP address fails to resolve. However, if this is a
1508 temporary failure, a 4xx temporary failure is returned.
1509 If the look-up succeeds, but returns an apparently forged
1510 value, this is treated as a temporary failure with a 4xx
1515 Exceptions based on access entries are discussed below.
1516 Any IP address matched using $=R (the "relay-domains" file)
1517 is excepted from the rules. Since we have explicitly
1518 allowed relaying for this host, based on IP address, we
1519 ignore the rDNS failure.
1521 The philosophical assumption here is that most users do
1522 not control their rDNS. They should be able to send mail
1523 through their ISP, whether or not they have valid rDNS.
1524 The class $=R, roughly speaking, contains those IP addresses
1525 and address ranges for which we are the ISP, or are acting
1528 If `delay_checks' is in effect (recommended), then any
1529 sender who has authenticated is also excepted from the
1530 restrictions. This happens because the rules produced by
1531 this FEATURE() will not be applied to authenticated senders
1532 (assuming `delay_checks').
1539 will whitelist IP address 1.2.3.4, so that the rDNS
1540 blocking does apply to that IP address
1543 Connect:1.2.3.4 REJECT
1544 will have the effect of forcing a temporary failure for
1545 that address to be treated as a permanent failure.
1547 badmx Reject envelope sender addresses (MAIL) whose domain part
1548 resolves to a "bad" MX record. By default these are
1549 MX records which resolve to A records that match the
1552 ^(127\.|10\.|0\.0\.0\.0)
1554 This default regular expression can be overridden by
1555 specifying an argument, e.g.,
1557 FEATURE(`badmx', `^127\.0\.0\.1')
1559 Note: this feature requires that the sendmail binary
1560 has been compiled with the options MAP_REGEX and
1567 Some things just can't be called features. To make this clear,
1568 they go in the hack subdirectory and are referenced using the HACK
1569 macro. These will tend to be site-dependent. The release
1570 includes the Berkeley-dependent "cssubdomain" hack (that makes
1571 sendmail accept local names in either Berkeley.EDU or CS.Berkeley.EDU;
1572 this is intended as a short-term aid while moving hosts into
1576 +--------------------+
1577 | SITE CONFIGURATION |
1578 +--------------------+
1580 *****************************************************
1581 * This section is really obsolete, and is preserved *
1582 * only for back compatibility. You should plan on *
1583 * using mailertables for new installations. In *
1584 * particular, it doesn't work for the newer forms *
1585 * of UUCP mailers, such as uucp-uudom. *
1586 *****************************************************
1588 Complex sites will need more local configuration information, such as
1589 lists of UUCP hosts they speak with directly. This can get a bit more
1590 tricky. For an example of a "complex" site, see cf/ucbvax.mc.
1592 The SITECONFIG macro allows you to indirectly reference site-dependent
1593 configuration information stored in the siteconfig subdirectory. For
1596 SITECONFIG(`uucp.ucbvax', `ucbvax', `U')
1598 reads the file uucp.ucbvax for local connection information. The
1599 second parameter is the local name (in this case just "ucbvax" since
1600 it is locally connected, and hence a UUCP hostname). The third
1601 parameter is the name of both a macro to store the local name (in
1602 this case, {U}) and the name of the class (e.g., {U}) in which to store
1603 the host information read from the file. Another SITECONFIG line reads
1605 SITECONFIG(`uucp.ucbarpa', `ucbarpa.Berkeley.EDU', `W')
1607 This says that the file uucp.ucbarpa contains the list of UUCP sites
1608 connected to ucbarpa.Berkeley.EDU. Class {W} will be used to
1609 store this list, and $W is defined to be ucbarpa.Berkeley.EDU, that
1610 is, the name of the relay to which the hosts listed in uucp.ucbarpa
1611 are connected. [The machine ucbarpa is gone now, but this
1612 out-of-date configuration file has been left around to demonstrate
1613 how you might do this.]
1615 Note that the case of SITECONFIG with a third parameter of ``U'' is
1616 special; the second parameter is assumed to be the UUCP name of the
1617 local site, rather than the name of a remote site, and the UUCP name
1618 is entered into class {w} (the list of local hostnames) as $U.UUCP.
1620 The siteconfig file (e.g., siteconfig/uucp.ucbvax.m4) contains nothing
1621 more than a sequence of SITE macros describing connectivity. For
1627 The second example demonstrates that you can use two names on the
1628 same line; these are usually aliases for the same host (or are at
1629 least in the same company).
1631 The macro LOCAL_UUCP can be used to add rules into the generated
1632 cf file at the place where MAILER(`uucp') inserts its rules. This
1633 should only be used if really necessary.
1635 +--------------------+
1636 | USING UUCP MAILERS |
1637 +--------------------+
1639 It's hard to get UUCP mailers right because of the extremely ad hoc
1640 nature of UUCP addressing. These config files are really designed
1641 for domain-based addressing, even for UUCP sites.
1643 There are four UUCP mailers available. The choice of which one to
1644 use is partly a matter of local preferences and what is running at
1645 the other end of your UUCP connection. Unlike good protocols that
1646 define what will go over the wire, UUCP uses the policy that you
1647 should do what is right for the other end; if they change, you have
1648 to change. This makes it hard to do the right thing, and discourages
1649 people from updating their software. In general, if you can avoid
1652 The major choice is whether to go for a domainized scheme or a
1653 non-domainized scheme. This depends entirely on what the other
1654 end will recognize. If at all possible, you should encourage the
1655 other end to go to a domain-based system -- non-domainized addresses
1656 don't work entirely properly.
1658 The four mailers are:
1660 uucp-old (obsolete name: "uucp")
1661 This is the oldest, the worst (but the closest to UUCP) way of
1662 sending messages across UUCP connections. It does bangify
1663 everything and prepends $U (your UUCP name) to the sender's
1664 address (which can already be a bang path itself). It can
1665 only send to one address at a time, so it spends a lot of
1666 time copying duplicates of messages. Avoid this if at all
1669 uucp-new (obsolete name: "suucp")
1670 The same as above, except that it assumes that in one rmail
1671 command you can specify several recipients. It still has a
1672 lot of other problems.
1675 This UUCP mailer keeps everything as domain addresses.
1676 Basically, it uses the SMTP mailer rewriting rules. This mailer
1677 is only included if MAILER(`smtp') is specified before
1680 Unfortunately, a lot of UUCP mailer transport agents require
1681 bangified addresses in the envelope, although you can use
1682 domain-based addresses in the message header. (The envelope
1683 shows up as the From_ line on UNIX mail.) So....
1686 This is a cross between uucp-new (for the envelope addresses)
1687 and uucp-dom (for the header addresses). It bangifies the
1688 envelope sender (From_ line in messages) without adding the
1689 local hostname, unless there is no host name on the address
1690 at all (e.g., "wolf") or the host component is a UUCP host name
1691 instead of a domain name ("somehost!wolf" instead of
1692 "some.dom.ain!wolf"). This is also included only if MAILER(`smtp')
1693 is also specified earlier.
1697 On host grasp.insa-lyon.fr (UUCP host name "grasp"), the following
1698 summarizes the sender rewriting for various mailers.
1700 Mailer sender rewriting in the envelope
1701 ------ ------ -------------------------
1702 uucp-{old,new} wolf grasp!wolf
1703 uucp-dom wolf wolf@grasp.insa-lyon.fr
1704 uucp-uudom wolf grasp.insa-lyon.fr!wolf
1706 uucp-{old,new} wolf@fr.net grasp!fr.net!wolf
1707 uucp-dom wolf@fr.net wolf@fr.net
1708 uucp-uudom wolf@fr.net fr.net!wolf
1710 uucp-{old,new} somehost!wolf grasp!somehost!wolf
1711 uucp-dom somehost!wolf somehost!wolf@grasp.insa-lyon.fr
1712 uucp-uudom somehost!wolf grasp.insa-lyon.fr!somehost!wolf
1714 If you are using one of the domainized UUCP mailers, you really want
1715 to convert all UUCP addresses to domain format -- otherwise, it will
1716 do it for you (and probably not the way you expected). For example,
1717 if you have the address foo!bar!baz (and you are not sending to foo),
1718 the heuristics will add the @uucp.relay.name or @local.host.name to
1719 this address. However, if you map foo to foo.host.name first, it
1720 will not add the local hostname. You can do this using the uucpdomain
1724 +-------------------+
1725 | TWEAKING RULESETS |
1726 +-------------------+
1728 For more complex configurations, you can define special rules.
1729 The macro LOCAL_RULE_3 introduces rules that are used in canonicalizing
1730 the names. Any modifications made here are reflected in the header.
1732 A common use is to convert old UUCP addresses to SMTP addresses using
1733 the UUCPSMTP macro. For example:
1736 UUCPSMTP(`decvax', `decvax.dec.com')
1737 UUCPSMTP(`research', `research.att.com')
1739 will cause addresses of the form "decvax!user" and "research!user"
1740 to be converted to "user@decvax.dec.com" and "user@research.att.com"
1743 This could also be used to look up hosts in a database map:
1746 R$* < @ $+ > $* $: $1 < @ $(hostmap $2 $) > $3
1748 This map would be defined in the LOCAL_CONFIG portion, as shown below.
1750 Similarly, LOCAL_RULE_0 can be used to introduce new parsing rules.
1751 For example, new rules are needed to parse hostnames that you accept
1752 via MX records. For example, you might have:
1755 R$+ <@ host.dom.ain.> $#uucp $@ cnmat $: $1 < @ host.dom.ain.>
1757 You would use this if you had installed an MX record for cnmat.Berkeley.EDU
1758 pointing at this host; this rule catches the message and forwards it on
1761 You can also tweak rulesets 1 and 2 using LOCAL_RULE_1 and LOCAL_RULE_2.
1762 These rulesets are normally empty.
1764 A similar macro is LOCAL_CONFIG. This introduces lines added after the
1765 boilerplate option setting but before rulesets. Do not declare rulesets in
1766 the LOCAL_CONFIG section. It can be used to declare local database maps or
1767 whatever. For example:
1770 Khostmap hash /etc/mail/hostmap
1771 Kyplocal nis -m hosts.byname
1774 +---------------------------+
1775 | MASQUERADING AND RELAYING |
1776 +---------------------------+
1778 You can have your host masquerade as another using
1780 MASQUERADE_AS(`host.domain')
1782 This causes mail being sent to be labeled as coming from the
1783 indicated host.domain, rather than $j. One normally masquerades as
1784 one of one's own subdomains (for example, it's unlikely that
1785 Berkeley would choose to masquerade as an MIT site). This
1786 behaviour is modified by a plethora of FEATUREs; in particular, see
1787 masquerade_envelope, allmasquerade, limited_masquerade, and
1788 masquerade_entire_domain.
1790 The masquerade name is not normally canonified, so it is important
1791 that it be your One True Name, that is, fully qualified and not a
1792 CNAME. However, if you use a CNAME, the receiving side may canonify
1793 it for you, so don't think you can cheat CNAME mapping this way.
1795 Normally the only addresses that are masqueraded are those that come
1796 from this host (that is, are either unqualified or in class {w}, the list
1797 of local domain names). You can augment this list, which is realized
1800 MASQUERADE_DOMAIN(`otherhost.domain')
1802 The effect of this is that although mail to user@otherhost.domain
1803 will not be delivered locally, any mail including any user@otherhost.domain
1804 will, when relayed, be rewritten to have the MASQUERADE_AS address.
1805 This can be a space-separated list of names.
1807 If these names are in a file, you can use
1809 MASQUERADE_DOMAIN_FILE(`filename')
1811 to read the list of names from the indicated file (i.e., to add
1812 elements to class {M}).
1814 To exempt hosts or subdomains from being masqueraded, you can use
1816 MASQUERADE_EXCEPTION(`host.domain')
1818 This can come handy if you want to masquerade a whole domain
1819 except for one (or a few) host(s). If these names are in a file,
1822 MASQUERADE_EXCEPTION_FILE(`filename')
1824 Normally only header addresses are masqueraded. If you want to
1825 masquerade the envelope as well, use
1827 FEATURE(`masquerade_envelope')
1829 There are always users that need to be "exposed" -- that is, their
1830 internal site name should be displayed instead of the masquerade name.
1831 Root is an example (which has been "exposed" by default prior to 8.10).
1832 You can add users to this list using
1834 EXPOSED_USER(`usernames')
1836 This adds users to class {E}; you could also use
1838 EXPOSED_USER_FILE(`filename')
1840 You can also arrange to relay all unqualified names (that is, names
1841 without @host) to a relay host. For example, if you have a central
1842 email server, you might relay to that host so that users don't have
1843 to have .forward files or aliases. You can do this using
1845 define(`LOCAL_RELAY', `mailer:hostname')
1847 The ``mailer:'' can be omitted, in which case the mailer defaults to
1848 "relay". There are some user names that you don't want relayed, perhaps
1849 because of local aliases. A common example is root, which may be
1850 locally aliased. You can add entries to this list using
1852 LOCAL_USER(`usernames')
1854 This adds users to class {L}; you could also use
1856 LOCAL_USER_FILE(`filename')
1858 If you want all incoming mail sent to a centralized hub, as for a
1859 shared /var/spool/mail scheme, use
1861 define(`MAIL_HUB', `mailer:hostname')
1863 Again, ``mailer:'' defaults to "relay". If you define both LOCAL_RELAY
1864 and MAIL_HUB _AND_ you have FEATURE(`stickyhost'), unqualified names will
1865 be sent to the LOCAL_RELAY and other local names will be sent to MAIL_HUB.
1866 Note: there is a (long standing) bug which keeps this combination from
1867 working for addresses of the form user+detail.
1868 Names in class {L} will be delivered locally, so you MUST have aliases or
1869 .forward files for them.
1871 For example, if you are on machine mastodon.CS.Berkeley.EDU and you have
1872 FEATURE(`stickyhost'), the following combinations of settings will have the
1875 email sent to.... eric eric@mastodon.CS.Berkeley.EDU
1877 LOCAL_RELAY set to mail.CS.Berkeley.EDU (delivered locally)
1878 mail.CS.Berkeley.EDU (no local aliasing) (aliasing done)
1880 MAIL_HUB set to mammoth.CS.Berkeley.EDU mammoth.CS.Berkeley.EDU
1881 mammoth.CS.Berkeley.EDU (aliasing done) (aliasing done)
1883 Both LOCAL_RELAY and mail.CS.Berkeley.EDU mammoth.CS.Berkeley.EDU
1884 MAIL_HUB set as above (no local aliasing) (aliasing done)
1886 If you do not have FEATURE(`stickyhost') set, then LOCAL_RELAY and
1887 MAIL_HUB act identically, with MAIL_HUB taking precedence.
1889 If you want all outgoing mail to go to a central relay site, define
1890 SMART_HOST as well. Briefly:
1892 LOCAL_RELAY applies to unqualified names (e.g., "eric").
1893 MAIL_HUB applies to names qualified with the name of the
1894 local host (e.g., "eric@mastodon.CS.Berkeley.EDU").
1895 SMART_HOST applies to names qualified with other hosts or
1896 bracketed addresses (e.g., "eric@mastodon.CS.Berkeley.EDU"
1897 or "eric@[127.0.0.1]").
1899 However, beware that other relays (e.g., UUCP_RELAY, BITNET_RELAY,
1900 DECNET_RELAY, and FAX_RELAY) take precedence over SMART_HOST, so if you
1901 really want absolutely everything to go to a single central site you will
1902 need to unset all the other relays -- or better yet, find or build a
1903 minimal config file that does this.
1905 For duplicate suppression to work properly, the host name is best
1906 specified with a terminal dot:
1908 define(`MAIL_HUB', `host.domain.')
1909 note the trailing dot ---^
1912 +-------------------------------------------+
1913 | USING LDAP FOR ALIASES, MAPS, AND CLASSES |
1914 +-------------------------------------------+
1916 LDAP can be used for aliases, maps, and classes by either specifying your
1917 own LDAP map specification or using the built-in default LDAP map
1918 specification. The built-in default specifications all provide lookups
1919 which match against either the machine's fully qualified hostname (${j}) or
1920 a "cluster". The cluster allows you to share LDAP entries among a large
1921 number of machines without having to enter each of the machine names into
1922 each LDAP entry. To set the LDAP cluster name to use for a particular
1923 machine or set of machines, set the confLDAP_CLUSTER m4 variable to a
1924 unique name. For example:
1926 define(`confLDAP_CLUSTER', `Servers')
1928 Here, the word `Servers' will be the cluster name. As an example, assume
1929 that smtp.sendmail.org, etrn.sendmail.org, and mx.sendmail.org all belong
1930 to the Servers cluster.
1932 Some of the LDAP LDIF examples below show use of the Servers cluster.
1933 Every entry must have either a sendmailMTAHost or sendmailMTACluster
1934 attribute or it will be ignored. Be careful as mixing clusters and
1935 individual host records can have surprising results (see the CAUTION
1938 See the file cf/sendmail.schema for the actual LDAP schemas. Note that
1939 this schema (and therefore the lookups and examples below) is experimental
1940 at this point as it has had little public review. Therefore, it may change
1941 in future versions. Feedback via sendmail-YYYY@support.sendmail.org is
1942 encouraged (replace YYYY with the current year, e.g., 2005).
1948 The ALIAS_FILE (O AliasFile) option can be set to use LDAP for alias
1949 lookups. To use the default schema, simply use:
1951 define(`ALIAS_FILE', `ldap:')
1953 By doing so, you will use the default schema which expands to a map
1954 declared as follows:
1956 ldap -k (&(objectClass=sendmailMTAAliasObject)
1957 (sendmailMTAAliasGrouping=aliases)
1958 (|(sendmailMTACluster=${sendmailMTACluster})
1959 (sendmailMTAHost=$j))
1960 (sendmailMTAKey=%0))
1961 -v sendmailMTAAliasValue,sendmailMTAAliasSearch:FILTER:sendmailMTAAliasObject,sendmailMTAAliasURL:URL:sendmailMTAAliasObject
1964 NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
1965 used when the binary expands the `ldap:' token as the AliasFile option is
1966 not actually macro-expanded when read from the sendmail.cf file.
1968 Example LDAP LDIF entries might be:
1970 dn: sendmailMTAKey=sendmail-list, dc=sendmail, dc=org
1971 objectClass: sendmailMTA
1972 objectClass: sendmailMTAAlias
1973 objectClass: sendmailMTAAliasObject
1974 sendmailMTAAliasGrouping: aliases
1975 sendmailMTAHost: etrn.sendmail.org
1976 sendmailMTAKey: sendmail-list
1977 sendmailMTAAliasValue: ca@example.org
1978 sendmailMTAAliasValue: eric
1979 sendmailMTAAliasValue: gshapiro@example.com
1981 dn: sendmailMTAKey=owner-sendmail-list, dc=sendmail, dc=org
1982 objectClass: sendmailMTA
1983 objectClass: sendmailMTAAlias
1984 objectClass: sendmailMTAAliasObject
1985 sendmailMTAAliasGrouping: aliases
1986 sendmailMTAHost: etrn.sendmail.org
1987 sendmailMTAKey: owner-sendmail-list
1988 sendmailMTAAliasValue: eric
1990 dn: sendmailMTAKey=postmaster, dc=sendmail, dc=org
1991 objectClass: sendmailMTA
1992 objectClass: sendmailMTAAlias
1993 objectClass: sendmailMTAAliasObject
1994 sendmailMTAAliasGrouping: aliases
1995 sendmailMTACluster: Servers
1996 sendmailMTAKey: postmaster
1997 sendmailMTAAliasValue: eric
1999 Here, the aliases sendmail-list and owner-sendmail-list will be available
2000 only on etrn.sendmail.org but the postmaster alias will be available on
2001 every machine in the Servers cluster (including etrn.sendmail.org).
2003 CAUTION: aliases are additive so that entries like these:
2005 dn: sendmailMTAKey=bob, dc=sendmail, dc=org
2006 objectClass: sendmailMTA
2007 objectClass: sendmailMTAAlias
2008 objectClass: sendmailMTAAliasObject
2009 sendmailMTAAliasGrouping: aliases
2010 sendmailMTACluster: Servers
2012 sendmailMTAAliasValue: eric
2014 dn: sendmailMTAKey=bobetrn, dc=sendmail, dc=org
2015 objectClass: sendmailMTA
2016 objectClass: sendmailMTAAlias
2017 objectClass: sendmailMTAAliasObject
2018 sendmailMTAAliasGrouping: aliases
2019 sendmailMTAHost: etrn.sendmail.org
2021 sendmailMTAAliasValue: gshapiro
2023 would mean that on all of the hosts in the cluster, mail to bob would go to
2024 eric EXCEPT on etrn.sendmail.org in which case it would go to BOTH eric and
2027 If you prefer not to use the default LDAP schema for your aliases, you can
2028 specify the map parameters when setting ALIAS_FILE. For example:
2030 define(`ALIAS_FILE', `ldap:-k (&(objectClass=mailGroup)(mail=%0)) -v mgrpRFC822MailMember')
2036 FEATURE()'s which take an optional map definition argument (e.g., access,
2037 mailertable, virtusertable, etc.) can instead take the special keyword
2040 FEATURE(`access_db', `LDAP')
2041 FEATURE(`virtusertable', `LDAP')
2043 When this keyword is given, that map will use LDAP lookups consisting of
2044 the objectClass sendmailMTAClassObject, the attribute sendmailMTAMapName
2045 with the map name, a search attribute of sendmailMTAKey, and the value
2046 attribute sendmailMTAMapValue.
2048 The values for sendmailMTAMapName are:
2050 FEATURE() sendmailMTAMapName
2051 --------- ------------------
2056 genericstable generics
2058 uucpdomain uucpdomain
2059 virtusertable virtuser
2061 For example, FEATURE(`mailertable', `LDAP') would use the map definition:
2063 Kmailertable ldap -k (&(objectClass=sendmailMTAMapObject)
2064 (sendmailMTAMapName=mailer)
2065 (|(sendmailMTACluster=${sendmailMTACluster})
2066 (sendmailMTAHost=$j))
2067 (sendmailMTAKey=%0))
2068 -1 -v sendmailMTAMapValue,sendmailMTAMapSearch:FILTER:sendmailMTAMapObject,sendmailMTAMapURL:URL:sendmailMTAMapObject
2070 An example LDAP LDIF entry using this map might be:
2072 dn: sendmailMTAMapName=mailer, dc=sendmail, dc=org
2073 objectClass: sendmailMTA
2074 objectClass: sendmailMTAMap
2075 sendmailMTACluster: Servers
2076 sendmailMTAMapName: mailer
2078 dn: sendmailMTAKey=example.com, sendmailMTAMapName=mailer, dc=sendmail, dc=org
2079 objectClass: sendmailMTA
2080 objectClass: sendmailMTAMap
2081 objectClass: sendmailMTAMapObject
2082 sendmailMTAMapName: mailer
2083 sendmailMTACluster: Servers
2084 sendmailMTAKey: example.com
2085 sendmailMTAMapValue: relay:[smtp.example.com]
2087 CAUTION: If your LDAP database contains the record above and *ALSO* a host
2088 specific record such as:
2090 dn: sendmailMTAKey=example.com@etrn, sendmailMTAMapName=mailer, dc=sendmail, dc=org
2091 objectClass: sendmailMTA
2092 objectClass: sendmailMTAMap
2093 objectClass: sendmailMTAMapObject
2094 sendmailMTAMapName: mailer
2095 sendmailMTAHost: etrn.sendmail.org
2096 sendmailMTAKey: example.com
2097 sendmailMTAMapValue: relay:[mx.example.com]
2099 then these entries will give unexpected results. When the lookup is done
2100 on etrn.sendmail.org, the effect is that there is *NO* match at all as maps
2101 require a single match. Since the host etrn.sendmail.org is also in the
2102 Servers cluster, LDAP would return two answers for the example.com map key
2103 in which case sendmail would treat this as no match at all.
2105 If you prefer not to use the default LDAP schema for your maps, you can
2106 specify the map parameters when using the FEATURE(). For example:
2108 FEATURE(`access_db', `ldap:-1 -k (&(objectClass=mapDatabase)(key=%0)) -v value')
2114 Normally, classes can be filled via files or programs. As of 8.12, they
2115 can also be filled via map lookups using a new syntax:
2117 F{ClassName}mapkey@mapclass:mapspec
2119 mapkey is optional and if not provided the map key will be empty. This can
2120 be used with LDAP to read classes from LDAP. Note that the lookup is only
2121 done when sendmail is initially started. Use the special value `@LDAP' to
2122 use the default LDAP schema. For example:
2124 RELAY_DOMAIN_FILE(`@LDAP')
2126 would put all of the attribute sendmailMTAClassValue values of LDAP records
2127 with objectClass sendmailMTAClass and an attribute sendmailMTAClassName of
2128 'R' into class $={R}. In other words, it is equivalent to the LDAP map
2131 F{R}@ldap:-k (&(objectClass=sendmailMTAClass)
2132 (sendmailMTAClassName=R)
2133 (|(sendmailMTACluster=${sendmailMTACluster})
2134 (sendmailMTAHost=$j)))
2135 -v sendmailMTAClassValue,sendmailMTAClassSearch:FILTER:sendmailMTAClass,sendmailMTAClassURL:URL:sendmailMTAClass
2137 NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
2138 used when the binary expands the `@LDAP' token as class declarations are
2139 not actually macro-expanded when read from the sendmail.cf file.
2141 This can be used with class related commands such as RELAY_DOMAIN_FILE(),
2142 MASQUERADE_DOMAIN_FILE(), etc:
2144 Command sendmailMTAClassName
2145 ------- --------------------
2146 CANONIFY_DOMAIN_FILE() Canonify
2147 EXPOSED_USER_FILE() E
2148 GENERICS_DOMAIN_FILE() G
2149 LDAPROUTE_DOMAIN_FILE() LDAPRoute
2150 LDAPROUTE_EQUIVALENT_FILE() LDAPRouteEquiv
2152 MASQUERADE_DOMAIN_FILE() M
2153 MASQUERADE_EXCEPTION_FILE() N
2154 RELAY_DOMAIN_FILE() R
2155 VIRTUSER_DOMAIN_FILE() VirtHost
2157 You can also add your own as any 'F'ile class of the form:
2161 will use "ClassName" for the sendmailMTAClassName.
2163 An example LDAP LDIF entry would look like:
2165 dn: sendmailMTAClassName=R, dc=sendmail, dc=org
2166 objectClass: sendmailMTA
2167 objectClass: sendmailMTAClass
2168 sendmailMTACluster: Servers
2169 sendmailMTAClassName: R
2170 sendmailMTAClassValue: sendmail.org
2171 sendmailMTAClassValue: example.com
2172 sendmailMTAClassValue: 10.56.23
2174 CAUTION: If your LDAP database contains the record above and *ALSO* a host
2175 specific record such as:
2177 dn: sendmailMTAClassName=R@etrn.sendmail.org, dc=sendmail, dc=org
2178 objectClass: sendmailMTA
2179 objectClass: sendmailMTAClass
2180 sendmailMTAHost: etrn.sendmail.org
2181 sendmailMTAClassName: R
2182 sendmailMTAClassValue: example.com
2184 the result will be similar to the aliases caution above. When the lookup
2185 is done on etrn.sendmail.org, $={R} would contain all of the entries (from
2186 both the cluster match and the host match). In other words, the effective
2189 If you prefer not to use the default LDAP schema for your classes, you can
2190 specify the map parameters when using the class command. For example:
2192 VIRTUSER_DOMAIN_FILE(`@ldap:-k (&(objectClass=virtHosts)(host=*)) -v host')
2194 Remember, macros can not be used in a class declaration as the binary does
2202 FEATURE(`ldap_routing') can be used to implement the IETF Internet Draft
2203 LDAP Schema for Intranet Mail Routing
2204 (draft-lachman-laser-ldap-mail-routing-01). This feature enables
2205 LDAP-based rerouting of a particular address to either a different host
2206 or a different address. The LDAP lookup is first attempted on the full
2207 address (e.g., user@example.com) and then on the domain portion
2208 (e.g., @example.com). Be sure to setup your domain for LDAP routing using
2209 LDAPROUTE_DOMAIN(), e.g.:
2211 LDAPROUTE_DOMAIN(`example.com')
2213 Additionally, you can specify equivalent domains for LDAP routing using
2214 LDAPROUTE_EQUIVALENT() and LDAPROUTE_EQUIVALENT_FILE(). 'Equivalent'
2215 hostnames are mapped to $M (the masqueraded hostname for the server) before
2216 the LDAP query. For example, if the mail is addressed to
2217 user@host1.example.com, normally the LDAP lookup would only be done for
2218 'user@host1.example.com' and '@host1.example.com'. However, if
2219 LDAPROUTE_EQUIVALENT(`host1.example.com') is used, the lookups would also be
2220 done on 'user@example.com' and '@example.com' after attempting the
2221 host1.example.com lookups.
2223 By default, the feature will use the schemas as specified in the draft
2224 and will not reject addresses not found by the LDAP lookup. However,
2225 this behavior can be changed by giving additional arguments to the FEATURE()
2228 FEATURE(`ldap_routing', <mailHost>, <mailRoutingAddress>, <bounce>,
2229 <detail>, <nodomain>, <tempfail>)
2231 where <mailHost> is a map definition describing how to lookup an alternative
2232 mail host for a particular address; <mailRoutingAddress> is a map definition
2233 describing how to lookup an alternative address for a particular address;
2234 the <bounce> argument, if present and not the word "passthru", dictates
2235 that mail should be bounced if neither a mailHost nor mailRoutingAddress
2236 is found, if set to "sendertoo", the sender will be rejected if not
2237 found in LDAP; and <detail> indicates what actions to take if the address
2238 contains +detail information -- `strip' tries the lookup with the +detail
2239 and if no matches are found, strips the +detail and tries the lookup again;
2240 `preserve', does the same as `strip' but if a mailRoutingAddress match is
2241 found, the +detail information is copied to the new address; the <nodomain>
2242 argument, if present, will prevent the @domain lookup if the full
2243 address is not found in LDAP; the <tempfail> argument, if set to
2244 "tempfail", instructs the rules to give an SMTP 4XX temporary
2245 error if the LDAP server gives the MTA a temporary failure, or if set to
2246 "queue" (the default), the MTA will locally queue the mail.
2248 The default <mailHost> map definition is:
2250 ldap -1 -T<TMPF> -v mailHost -k (&(objectClass=inetLocalMailRecipient)
2251 (mailLocalAddress=%0))
2253 The default <mailRoutingAddress> map definition is:
2255 ldap -1 -T<TMPF> -v mailRoutingAddress
2256 -k (&(objectClass=inetLocalMailRecipient)
2257 (mailLocalAddress=%0))
2259 Note that neither includes the LDAP server hostname (-h server) or base DN
2260 (-b o=org,c=COUNTRY), both necessary for LDAP queries. It is presumed that
2261 your .mc file contains a setting for the confLDAP_DEFAULT_SPEC option with
2262 these settings. If this is not the case, the map definitions should be
2263 changed as described above. The "-T<TMPF>" is required in any user
2264 specified map definition to catch temporary errors.
2266 The following possibilities exist as a result of an LDAP lookup on an
2269 mailHost is mailRoutingAddress is Results in
2270 ----------- --------------------- ----------
2271 set to a set mail delivered to
2272 "local" host mailRoutingAddress
2274 set to a not set delivered to
2275 "local" host original address
2277 set to a set mailRoutingAddress
2278 remote host relayed to mailHost
2280 set to a not set original address
2281 remote host relayed to mailHost
2283 not set set mail delivered to
2286 not set not set delivered to
2287 original address *OR*
2288 bounced as unknown user
2290 The term "local" host above means the host specified is in class {w}. If
2291 the result would mean sending the mail to a different host, that host is
2292 looked up in the mailertable before delivery.
2294 Note that the last case depends on whether the third argument is given
2295 to the FEATURE() command. The default is to deliver the message to the
2298 The LDAP entries should be set up with an objectClass of
2299 inetLocalMailRecipient and the address be listed in a mailLocalAddress
2300 attribute. If present, there must be only one mailHost attribute and it
2301 must contain a fully qualified host name as its value. Similarly, if
2302 present, there must be only one mailRoutingAddress attribute and it must
2303 contain an RFC 822 compliant address. Some example LDAP records (in LDIF
2306 dn: uid=tom, o=example.com, c=US
2307 objectClass: inetLocalMailRecipient
2308 mailLocalAddress: tom@example.com
2309 mailRoutingAddress: thomas@mailhost.example.com
2311 This would deliver mail for tom@example.com to thomas@mailhost.example.com.
2313 dn: uid=dick, o=example.com, c=US
2314 objectClass: inetLocalMailRecipient
2315 mailLocalAddress: dick@example.com
2316 mailHost: eng.example.com
2318 This would relay mail for dick@example.com to the same address but redirect
2319 the mail to MX records listed for the host eng.example.com (unless the
2320 mailertable overrides).
2322 dn: uid=harry, o=example.com, c=US
2323 objectClass: inetLocalMailRecipient
2324 mailLocalAddress: harry@example.com
2325 mailHost: mktmail.example.com
2326 mailRoutingAddress: harry@mkt.example.com
2328 This would relay mail for harry@example.com to the MX records listed for
2329 the host mktmail.example.com using the new address harry@mkt.example.com
2330 when talking to that host.
2332 dn: uid=virtual.example.com, o=example.com, c=US
2333 objectClass: inetLocalMailRecipient
2334 mailLocalAddress: @virtual.example.com
2335 mailHost: server.example.com
2336 mailRoutingAddress: virtual@example.com
2338 This would send all mail destined for any username @virtual.example.com to
2339 the machine server.example.com's MX servers and deliver to the address
2340 virtual@example.com on that relay machine.
2343 +---------------------------------+
2344 | ANTI-SPAM CONFIGURATION CONTROL |
2345 +---------------------------------+
2347 The primary anti-spam features available in sendmail are:
2349 * Relaying is denied by default.
2350 * Better checking on sender information.
2354 Relaying (transmission of messages from a site outside your host (class
2355 {w}) to another site except yours) is denied by default. Note that this
2356 changed in sendmail 8.9; previous versions allowed relaying by default.
2357 If you really want to revert to the old behaviour, you will need to use
2358 FEATURE(`promiscuous_relay'). You can allow certain domains to relay
2359 through your server by adding their domain name or IP address to class
2360 {R} using RELAY_DOMAIN() and RELAY_DOMAIN_FILE() or via the access database
2361 (described below). Note that IPv6 addresses must be prefaced with "IPv6:".
2362 The file consists (like any other file based class) of entries listed on
2363 separate lines, e.g.,
2368 IPv6:2002:c0a8:51d2::23f4
2372 Notice: the last entry allows relaying for connections via a UNIX
2373 socket to the MTA/MSP. This might be necessary if your configuration
2374 doesn't allow relaying by other means in that case, e.g., by having
2375 localhost.$m in class {R} (make sure $m is not just a top level
2380 FEATURE(`relay_entire_domain')
2382 then any host in any of your local domains (that is, class {m})
2383 will be relayed (that is, you will accept mail either to or from any
2384 host in your domain).
2386 You can also allow relaying based on the MX records of the host
2387 portion of an incoming recipient address by using
2389 FEATURE(`relay_based_on_MX')
2391 For example, if your server receives a recipient of user@domain.com
2392 and domain.com lists your server in its MX records, the mail will be
2393 accepted for relay to domain.com. This feature may cause problems
2394 if MX lookups for the recipient domain are slow or time out. In that
2395 case, mail will be temporarily rejected. It is usually better to
2396 maintain a list of hosts/domains for which the server acts as relay.
2397 Note also that this feature will stop spammers from using your host
2398 to relay spam but it will not stop outsiders from using your server
2399 as a relay for their site (that is, they set up an MX record pointing
2400 to your mail server, and you will relay mail addressed to them
2401 without any prior arrangement). Along the same lines,
2403 FEATURE(`relay_local_from')
2405 will allow relaying if the sender specifies a return path (i.e.
2406 MAIL FROM:<user@domain>) domain which is a local domain. This is a
2407 dangerous feature as it will allow spammers to spam using your mail
2408 server by simply specifying a return address of user@your.domain.com.
2409 It should not be used unless absolutely necessary.
2410 A slightly better solution is
2412 FEATURE(`relay_mail_from')
2414 which allows relaying if the mail sender is listed as RELAY in the
2415 access map. If an optional argument `domain' (this is the literal
2416 word `domain', not a placeholder) is given, the domain portion of
2417 the mail sender is also checked to allowing relaying. This option
2418 only works together with the tag From: for the LHS of the access
2419 map entries. This feature allows spammers to abuse your mail server
2420 by specifying a return address that you enabled in your access file.
2421 This may be harder to figure out for spammers, but it should not
2422 be used unless necessary. Instead use SMTP AUTH or STARTTLS to
2423 allow relaying for roaming users.
2426 If source routing is used in the recipient address (e.g.,
2427 RCPT TO:<user%site.com@othersite.com>), sendmail will check
2428 user@site.com for relaying if othersite.com is an allowed relay host
2429 in either class {R}, class {m} if FEATURE(`relay_entire_domain') is used,
2430 or the access database if FEATURE(`access_db') is used. To prevent
2431 the address from being stripped down, use:
2433 FEATURE(`loose_relay_check')
2435 If you think you need to use this feature, you probably do not. This
2436 should only be used for sites which have no control over the addresses
2437 that they provide a gateway for. Use this FEATURE with caution as it
2438 can allow spammers to relay through your server if not setup properly.
2440 NOTICE: It is possible to relay mail through a system which the anti-relay
2441 rules do not prevent: the case of a system that does use FEATURE(`nouucp',
2442 `nospecial') (system A) and relays local messages to a mail hub (e.g., via
2443 LOCAL_RELAY or LUSER_RELAY) (system B). If system B doesn't use
2444 FEATURE(`nouucp') at all, addresses of the form
2445 <example.net!user@local.host> would be relayed to <user@example.net>.
2446 System A doesn't recognize `!' as an address separator and therefore
2447 forwards it to the mail hub which in turns relays it because it came from
2448 a trusted local host. So if a mailserver allows UUCP (bang-format)
2449 addresses, all systems from which it allows relaying should do the same
2450 or reject those addresses.
2452 As of 8.9, sendmail will refuse mail if the MAIL FROM: parameter has
2453 an unresolvable domain (i.e., one that DNS, your local name service,
2454 or special case rules in ruleset 3 cannot locate). This also applies
2455 to addresses that use domain literals, e.g., <user@[1.2.3.4]>, if the
2456 IP address can't be mapped to a host name. If you want to continue
2457 to accept such domains, e.g., because you are inside a firewall that
2458 has only a limited view of the Internet host name space (note that you
2459 will not be able to return mail to them unless you have some "smart
2460 host" forwarder), use
2462 FEATURE(`accept_unresolvable_domains')
2464 Alternatively, you can allow specific addresses by adding them to
2465 the access map, e.g.,
2467 From:unresolvable.domain OK
2471 Notice: domains which are temporarily unresolvable are (temporarily)
2472 rejected with a 451 reply code. If those domains should be accepted
2473 (which is discouraged) then you can use
2478 sendmail will also refuse mail if the MAIL FROM: parameter is not
2479 fully qualified (i.e., contains a domain as well as a user). If you
2480 want to continue to accept such senders, use
2482 FEATURE(`accept_unqualified_senders')
2484 Setting the DaemonPortOptions modifier 'u' overrides the default behavior,
2485 i.e., unqualified addresses are accepted even without this FEATURE. If
2486 this FEATURE is not used, the DaemonPortOptions modifier 'f' can be used
2487 to enforce fully qualified domain names.
2489 An ``access'' database can be created to accept or reject mail from
2490 selected domains. For example, you may choose to reject all mail
2491 originating from known spammers. To enable such a database, use
2493 FEATURE(`access_db')
2495 Notice: the access database is applied to the envelope addresses
2496 and the connection information, not to the header.
2498 The FEATURE macro can accept as second parameter the key file
2499 definition for the database; for example
2501 FEATURE(`access_db', `hash -T<TMPF> /etc/mail/access_map')
2503 Notice: If a second argument is specified it must contain the option
2504 `-T<TMPF>' as shown above. The optional parameters may be
2506 `skip' enables SKIP as value part (see below).
2507 `lookupdotdomain' another way to enable the feature of the
2508 same name (see above).
2509 `relaytofulladdress' enable entries of the form
2510 To:user@example.com RELAY
2511 to allow relaying to just a specific
2512 e-mail address instead of an entire domain.
2514 Remember, since /etc/mail/access is a database, after creating the text
2515 file as described below, you must use makemap to create the database
2518 makemap hash /etc/mail/access < /etc/mail/access
2520 The table itself uses e-mail addresses, domain names, and network
2521 numbers as keys. Note that IPv6 addresses must be prefaced with "IPv6:".
2524 From:spammer@aol.com REJECT
2525 From:cyberspammer.com REJECT
2526 Connect:cyberspammer.com REJECT
2528 Connect:192.168.212 REJECT
2529 Connect:IPv6:2002:c0a8:02c7 RELAY
2530 Connect:IPv6:2002:c0a8:51d2::23f4 REJECT
2532 would refuse mail from spammer@aol.com, any user from cyberspammer.com
2533 (or any host within the cyberspammer.com domain), any host in the entire
2534 top level domain TLD, 192.168.212.* network, and the IPv6 address
2535 2002:c0a8:51d2::23f4. It would allow relay for the IPv6 network
2536 2002:c0a8:02c7::/48.
2538 Entries in the access map should be tagged according to their type.
2539 Three tags are available:
2541 Connect: connection information (${client_addr}, ${client_name})
2542 From: envelope sender
2543 To: envelope recipient
2545 Notice: untagged entries are deprecated.
2547 If the required item is looked up in a map, it will be tried first
2548 with the corresponding tag in front, then (as fallback to enable
2549 backward compatibility) without any tag, unless the specific feature
2550 requires a tag. For example,
2552 From:spammer@some.dom REJECT
2553 To:friend.domain RELAY
2554 Connect:friend.domain OK
2555 Connect:from.domain RELAY
2556 From:good@another.dom OK
2557 From:another.dom REJECT
2559 This would deny mails from spammer@some.dom but you could still
2560 send mail to that address even if FEATURE(`blacklist_recipients')
2561 is enabled. Your system will allow relaying to friend.domain, but
2562 not from it (unless enabled by other means). Connections from that
2563 domain will be allowed even if it ends up in one of the DNS based
2564 rejection lists. Relaying is enabled from from.domain but not to
2565 it (since relaying is based on the connection information for
2566 outgoing relaying, the tag Connect: must be used; for incoming
2567 relaying, which is based on the recipient address, To: must be
2568 used). The last two entries allow mails from good@another.dom but
2569 reject mail from all other addresses with another.dom as domain
2573 The value part of the map can contain:
2575 OK Accept mail even if other rules in the running
2576 ruleset would reject it, for example, if the domain
2577 name is unresolvable. "Accept" does not mean
2578 "relay", but at most acceptance for local
2579 recipients. That is, OK allows less than RELAY.
2580 RELAY Accept mail addressed to the indicated domain
2581 (or address if `relaytofulladdress' is set) or
2582 received from the indicated domain for relaying
2583 through your SMTP server. RELAY also serves as
2584 an implicit OK for the other checks.
2585 REJECT Reject the sender or recipient with a general
2587 DISCARD Discard the message completely using the
2588 $#discard mailer. If it is used in check_compat,
2589 it affects only the designated recipient, not
2590 the whole message as it does in all other cases.
2591 This should only be used if really necessary.
2592 SKIP This can only be used for host/domain names
2593 and IP addresses/nets. It will abort the current
2594 search for this entry without accepting or rejecting
2595 it but causing the default action.
2596 ### any text where ### is an RFC 821 compliant error code and
2597 "any text" is a message to return for the command.
2598 The entire string should be quoted to avoid
2603 Otherwise sendmail formats the text as email
2604 addresses, e.g., it may remove spaces.
2605 This type is deprecated, use one of the two
2606 ERROR: entries below instead.
2608 as above, but useful to mark error messages as such.
2609 If quotes need to be used to avoid modifications
2610 (see above), they should be placed like this:
2612 ERROR:"### any text"
2614 ERROR:D.S.N:### any text
2615 where D.S.N is an RFC 1893 compliant error code
2616 and the rest as above. If quotes need to be used
2617 to avoid modifications, they should be placed
2620 ERROR:D.S.N:"### any text"
2623 Quarantine the message using the given text as the
2624 quarantining reason.
2628 From:cyberspammer.com ERROR:"550 We don't accept mail from spammers"
2629 From:okay.cyberspammer.com OK
2630 Connect:sendmail.org RELAY
2631 To:sendmail.org RELAY
2632 Connect:128.32 RELAY
2633 Connect:128.32.2 SKIP
2634 Connect:IPv6:1:2:3:4:5:6:7 RELAY
2635 Connect:suspicious.example.com QUARANTINE:Mail from suspicious host
2636 Connect:[127.0.0.3] OK
2637 Connect:[IPv6:1:2:3:4:5:6:7:8] OK
2639 would accept mail from okay.cyberspammer.com, but would reject mail
2640 from all other hosts at cyberspammer.com with the indicated message.
2641 It would allow relaying mail from and to any hosts in the sendmail.org
2642 domain, and allow relaying from the IPv6 1:2:3:4:5:6:7:* network
2643 and from the 128.32.*.* network except for the 128.32.2.* network,
2644 which shows how SKIP is useful to exempt subnets/subdomains. The
2645 last two entries are for checks against ${client_name} if the IP
2646 address doesn't resolve to a hostname (or is considered as "may be
2647 forged"). That is, using square brackets means these are host
2648 names, not network numbers.
2650 Warning: if you change the RFC 821 compliant error code from the default
2651 value of 550, then you should probably also change the RFC 1893 compliant
2652 error code to match it. For example, if you use
2654 To:user@example.com ERROR:450 mailbox full
2656 the error returned would be "450 5.0.0 mailbox full" which is wrong.
2657 Use "ERROR:4.2.2:450 mailbox full" instead.
2659 Note, UUCP users may need to add hostname.UUCP to the access database
2664 FEATURE(`relay_hosts_only')
2666 then the above example will allow relaying for sendmail.org, but not
2667 hosts within the sendmail.org domain. Note that this will also require
2668 hosts listed in class {R} to be fully qualified host names.
2670 You can also use the access database to block sender addresses based on
2671 the username portion of the address. For example:
2673 From:FREE.STEALTH.MAILER@ ERROR:550 Spam not accepted
2675 Note that you must include the @ after the username to signify that
2676 this database entry is for checking only the username portion of the
2681 FEATURE(`blacklist_recipients')
2683 then you can add entries to the map for local users, hosts in your
2684 domains, or addresses in your domain which should not receive mail:
2686 To:badlocaluser@ ERROR:550 Mailbox disabled for badlocaluser
2687 To:host.my.TLD ERROR:550 That host does not accept mail
2688 To:user@other.my.TLD ERROR:550 Mailbox disabled for this recipient
2690 This would prevent a recipient of badlocaluser in any of the local
2691 domains (class {w}), any user at host.my.TLD, and the single address
2692 user@other.my.TLD from receiving mail. Please note: a local username
2693 must be now tagged with an @ (this is consistent with the check of
2694 the sender address, and hence it is possible to distinguish between
2695 hostnames and usernames). Enabling this feature will keep you from
2696 sending mails to all addresses that have an error message or REJECT
2697 as value part in the access map. Taking the example from above:
2699 spammer@aol.com REJECT
2700 cyberspammer.com REJECT
2702 Mail can't be sent to spammer@aol.com or anyone at cyberspammer.com.
2703 That's why tagged entries should be used.
2705 There are several DNS based blacklists which can be found by
2706 querying a search engine. These are databases of spammers
2707 maintained in DNS. To use such a database, specify
2709 FEATURE(`dnsbl', `dnsbl.example.com')
2711 This will cause sendmail to reject mail from any site listed in the
2712 DNS based blacklist. You must select a DNS based blacklist domain
2713 to check by specifying an argument to the FEATURE. The default
2716 Rejected: IP-ADDRESS listed at SERVER
2718 where IP-ADDRESS and SERVER are replaced by the appropriate
2719 information. A second argument can be used to specify a different
2720 text or action. For example,
2722 FEATURE(`dnsbl', `dnsbl.example.com', `quarantine')
2724 would quarantine the message if the client IP address is listed
2725 at `dnsbl.example.com'.
2727 By default, temporary lookup failures are ignored
2728 and hence cause the connection not to be rejected by the DNS based
2729 rejection list. This behavior can be changed by specifying a third
2730 argument, which must be either `t' or a full error message. For
2733 FEATURE(`dnsbl', `dnsbl.example.com', `',
2734 `"451 Temporary lookup failure for " $&{client_addr} " in dnsbl.example.com"')
2736 If `t' is used, the error message is:
2738 451 Temporary lookup failure of IP-ADDRESS at SERVER
2740 where IP-ADDRESS and SERVER are replaced by the appropriate
2743 This FEATURE can be included several times to query different
2744 DNS based rejection lists.
2746 Notice: to avoid checking your own local domains against those
2747 blacklists, use the access_db feature and add:
2750 Connect:127.0.0.1 RELAY
2752 to the access map, where 10.1 is your local network. You may
2753 want to use "RELAY" instead of "OK" to allow also relaying
2754 instead of just disabling the DNS lookups in the blacklists.
2757 The features described above make use of the check_relay, check_mail,
2758 and check_rcpt rulesets. Note that check_relay checks the SMTP
2759 client hostname and IP address when the connection is made to your
2760 server. It does not check if a mail message is being relayed to
2761 another server. That check is done in check_rcpt. If you wish to
2762 include your own checks, you can put your checks in the rulesets
2763 Local_check_relay, Local_check_mail, and Local_check_rcpt. For
2764 example if you wanted to block senders with all numeric usernames
2765 (i.e. 2312343@bigisp.com), you would use Local_check_mail and the
2769 Kallnumbers regex -a@MATCH ^[0-9]+$
2773 # check address against various regex checks
2774 R$* $: $>Parse0 $>3 $1
2775 R$+ < @ bigisp.com. > $* $: $(allnumbers $1 $)
2776 R@MATCH $#error $: 553 Header Error
2778 These rules are called with the original arguments of the corresponding
2779 check_* ruleset. If the local ruleset returns $#OK, no further checking
2780 is done by the features described above and the mail is accepted. If
2781 the local ruleset resolves to a mailer (such as $#error or $#discard),
2782 the appropriate action is taken. Other results starting with $# are
2783 interpreted by sendmail and may lead to unspecified behavior. Note: do
2784 NOT create a mailer with the name OK. Return values that do not start
2785 with $# are ignored, i.e., normal processing continues.
2790 By using FEATURE(`delay_checks') the rulesets check_mail and check_relay
2791 will not be called when a client connects or issues a MAIL command,
2792 respectively. Instead, those rulesets will be called by the check_rcpt
2793 ruleset; they will be skipped if a sender has been authenticated using
2794 a "trusted" mechanism, i.e., one that is defined via TRUST_AUTH_MECH().
2795 If check_mail returns an error then the RCPT TO command will be rejected
2796 with that error. If it returns some other result starting with $# then
2797 check_relay will be skipped. If the sender address (or a part of it) is
2798 listed in the access map and it has a RHS of OK or RELAY, then check_relay
2799 will be skipped. This has an interesting side effect: if your domain is
2800 my.domain and you have
2804 in the access map, then any e-mail with a sender address of
2805 <user@my.domain> will not be rejected by check_relay even though
2806 it would match the hostname or IP address. This allows spammers
2807 to get around DNS based blacklist by faking the sender address. To
2808 avoid this problem you have to use tagged entries:
2811 Connect:my.domain RELAY
2813 if you need those entries at all (class {R} may take care of them).
2815 FEATURE(`delay_checks') can take an optional argument:
2817 FEATURE(`delay_checks', `friend')
2818 enables spamfriend test
2819 FEATURE(`delay_checks', `hater')
2820 enables spamhater test
2822 If such an argument is given, the recipient will be looked up in the
2823 access map (using the tag Spam:). If the argument is `friend', then
2824 the default behavior is to apply the other rulesets and make a SPAM
2825 friend the exception. The rulesets check_mail and check_relay will be
2826 skipped only if the recipient address is found and has RHS FRIEND. If
2827 the argument is `hater', then the default behavior is to skip the rulesets
2828 check_mail and check_relay and make a SPAM hater the exception. The
2829 other two rulesets will be applied only if the recipient address is
2830 found and has RHS HATER.
2832 This allows for simple exceptions from the tests, e.g., by activating
2833 the friend option and having
2837 in the access map, mail to abuse@localdomain will get through (where
2838 "localdomain" is any domain in class {w}). It is also possible to
2839 specify a full address or an address with +detail:
2841 Spam:abuse@my.domain FRIEND
2842 Spam:me+abuse@ FRIEND
2843 Spam:spam.domain FRIEND
2845 Note: The required tag has been changed in 8.12 from To: to Spam:.
2846 This change is incompatible to previous versions. However, you can
2847 (for now) simply add the new entries to the access map, the old
2848 ones will be ignored. As soon as you removed the old entries from
2849 the access map, specify a third parameter (`n') to this feature and
2850 the backward compatibility rules will not be in the generated .cf
2856 You can also reject mail on the basis of the contents of headers.
2857 This is done by adding a ruleset call to the 'H' header definition command
2858 in sendmail.cf. For example, this can be used to check the validity of
2859 a Message-ID: header:
2862 HMessage-Id: $>CheckMessageId
2867 R$* $#error $: 553 Header Error
2869 The alternative format:
2871 HSubject: $>+CheckSubject
2873 that is, $>+ instead of $>, gives the full Subject: header including
2874 comments to the ruleset (comments in parentheses () are stripped
2877 A default ruleset for headers which don't have a specific ruleset
2878 defined for them can be given by:
2883 1. All rules act on tokens as explained in doc/op/op.{me,ps,txt}.
2884 That may cause problems with simple header checks due to the
2885 tokenization. It might be simpler to use a regex map and apply it
2887 2. There are no default rulesets coming with this distribution of
2888 sendmail. You can write your own, can search the WWW for examples,
2889 or take a look at cf/cf/knecht.mc.
2890 3. When using a default ruleset for headers, the name of the header
2891 currently being checked can be found in the $&{hdr_name} macro.
2893 After all of the headers are read, the check_eoh ruleset will be called for
2894 any final header-related checks. The ruleset is called with the number of
2895 headers and the size of all of the headers in bytes separated by $|. One
2896 example usage is to reject messages which do not have a Message-Id:
2897 header. However, the Message-Id: header is *NOT* a required header and is
2898 not a guaranteed spam indicator. This ruleset is an example and should
2899 probably not be used in production.
2903 HMessage-Id: $>CheckMessageId
2907 # Record the presence of the header
2908 R$* $: $(storage {MessageIdCheck} $@ OK $) $1
2910 R$* $#error $: 553 Header Error
2914 R$* $: < $&{MessageIdCheck} >
2915 # Clear the macro for the next message
2916 R$* $: $(storage {MessageIdCheck} $) $1
2917 # Has a Message-Id: header
2919 # Allow missing Message-Id: from local mail
2920 R$* $: < $&{client_name} >
2923 # Otherwise, reject the mail
2924 R$* $#error $: 553 Header Error
2927 +--------------------+
2928 | CONNECTION CONTROL |
2929 +--------------------+
2931 The features ratecontrol and conncontrol allow to establish connection
2932 limits per client IP address or net. These features can limit the
2933 rate of connections (connections per time unit) or the number of
2934 incoming SMTP connections, respectively. If enabled, appropriate
2935 rulesets are called at the end of check_relay, i.e., after DNS
2936 blacklists and generic access_db operations. The features require
2937 FEATURE(`access_db') to be listed earlier in the mc file.
2939 Note: FEATURE(`delay_checks') delays those connection control checks
2940 after a recipient address has been received, hence making these
2941 connection control features less useful. To run the checks as early
2942 as possible, specify the parameter `nodelay', e.g.,
2944 FEATURE(`ratecontrol', `nodelay')
2946 In that case, FEATURE(`delay_checks') has no effect on connection
2947 control (and it must be specified earlier in the mc file).
2949 An optional second argument `terminate' specifies whether the
2950 rulesets should return the error code 421 which will cause
2951 sendmail to terminate the session with that error if it is
2952 returned from check_relay, i.e., not delayed as explained in
2953 the previous paragraph. Example:
2955 FEATURE(`ratecontrol', `nodelay', `terminate')
2962 In this text, cert will be used as an abbreviation for X.509 certificate,
2963 DN (CN) is the distinguished (common) name of a cert, and CA is a
2964 certification authority, which signs (issues) certs.
2966 For STARTTLS to be offered by sendmail you need to set at least
2967 these variables (the file names and paths are just examples):
2969 define(`confCACERT_PATH', `/etc/mail/certs/')
2970 define(`confCACERT', `/etc/mail/certs/CA.cert.pem')
2971 define(`confSERVER_CERT', `/etc/mail/certs/my.cert.pem')
2972 define(`confSERVER_KEY', `/etc/mail/certs/my.key.pem')
2974 On systems which do not have the compile flag HASURANDOM set (see
2975 sendmail/README) you also must set confRAND_FILE.
2977 See doc/op/op.{me,ps,txt} for more information about these options,
2978 especially the sections ``Certificates for STARTTLS'' and ``PRNG for
2981 Macros related to STARTTLS are:
2983 ${cert_issuer} holds the DN of the CA (the cert issuer).
2984 ${cert_subject} holds the DN of the cert (called the cert subject).
2985 ${cn_issuer} holds the CN of the CA (the cert issuer).
2986 ${cn_subject} holds the CN of the cert (called the cert subject).
2987 ${tls_version} the TLS/SSL version used for the connection, e.g., TLSv1,
2988 TLSv1/SSLv3, SSLv3, SSLv2.
2989 ${cipher} the cipher used for the connection, e.g., EDH-DSS-DES-CBC3-SHA,
2990 EDH-RSA-DES-CBC-SHA, DES-CBC-MD5, DES-CBC3-SHA.
2991 ${cipher_bits} the keylength (in bits) of the symmetric encryption algorithm
2992 used for the connection.
2993 ${verify} holds the result of the verification of the presented cert.
2994 Possible values are:
2995 OK verification succeeded.
2996 NO no cert presented.
2997 NOT no cert requested.
2998 FAIL cert presented but could not be verified,
2999 e.g., the cert of the signing CA is missing.
3000 NONE STARTTLS has not been performed.
3001 TEMP temporary error occurred.
3002 PROTOCOL protocol error occurred (SMTP level).
3003 SOFTWARE STARTTLS handshake failed.
3004 ${server_name} the name of the server of the current outgoing SMTP
3006 ${server_addr} the address of the server of the current outgoing SMTP
3012 SMTP STARTTLS can allow relaying for remote SMTP clients which have
3013 successfully authenticated themselves. If the verification of the cert
3014 failed (${verify} != OK), relaying is subject to the usual rules.
3015 Otherwise the DN of the issuer is looked up in the access map using the
3016 tag CERTISSUER. If the resulting value is RELAY, relaying is allowed.
3017 If it is SUBJECT, the DN of the cert subject is looked up next in the
3018 access map using the tag CERTSUBJECT. If the value is RELAY, relaying
3021 To make things a bit more flexible (or complicated), the values for
3022 ${cert_issuer} and ${cert_subject} can be optionally modified by regular
3023 expressions defined in the m4 variables _CERT_REGEX_ISSUER_ and
3024 _CERT_REGEX_SUBJECT_, respectively. To avoid problems with those macros in
3025 rulesets and map lookups, they are modified as follows: each non-printable
3026 character and the characters '<', '>', '(', ')', '"', '+', ' ' are replaced
3027 by their HEX value with a leading '+'. For example:
3029 /C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/Email=
3030 darth+cert@endmail.org
3034 /C=US/ST=California/O=endmail.org/OU=private/CN=
3035 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
3037 (line breaks have been inserted for readability).
3039 The macros which are subject to this encoding are ${cert_subject},
3040 ${cert_issuer}, ${cn_subject}, and ${cn_issuer}.
3044 To allow relaying for everyone who can present a cert signed by
3046 /C=US/ST=California/O=endmail.org/OU=private/CN=
3047 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
3051 CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
3052 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org RELAY
3054 To allow relaying only for a subset of machines that have a cert signed by
3056 /C=US/ST=California/O=endmail.org/OU=private/CN=
3057 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
3061 CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
3062 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org SUBJECT
3063 CertSubject:/C=US/ST=California/O=endmail.org/OU=private/CN=
3064 DeathStar/Email=deathstar@endmail.org RELAY
3067 - line breaks have been inserted after "CN=" for readability,
3068 each tagged entry must be one (long) line in the access map.
3069 - if OpenSSL 0.9.7 or newer is used then the "Email=" part of a DN
3070 is replaced by "emailAddress=".
3072 Of course it is also possible to write a simple ruleset that allows
3073 relaying for everyone who can present a cert that can be verified, e.g.,
3080 Allowing Connections
3081 --------------------
3083 The rulesets tls_server, tls_client, and tls_rcpt are used to decide whether
3084 an SMTP connection is accepted (or should continue).
3086 tls_server is called when sendmail acts as client after a STARTTLS command
3087 (should) have been issued. The parameter is the value of ${verify}.
3089 tls_client is called when sendmail acts as server, after a STARTTLS command
3090 has been issued, and from check_mail. The parameter is the value of
3091 ${verify} and STARTTLS or MAIL, respectively.
3093 Both rulesets behave the same. If no access map is in use, the connection
3094 will be accepted unless ${verify} is SOFTWARE, in which case the connection
3095 is always aborted. For tls_server/tls_client, ${client_name}/${server_name}
3096 is looked up in the access map using the tag TLS_Srv/TLS_Clt, which is done
3097 with the ruleset LookUpDomain. If no entry is found, ${client_addr}
3098 (${server_addr}) is looked up in the access map (same tag, ruleset
3099 LookUpAddr). If this doesn't result in an entry either, just the tag is
3100 looked up in the access map (included the trailing colon). Notice:
3101 requiring that e-mail is sent to a server only encrypted, e.g., via
3103 TLS_Srv:secure.domain ENCR:112
3105 doesn't necessarily mean that e-mail sent to that domain is encrypted.
3106 If the domain has multiple MX servers, e.g.,
3108 secure.domain. IN MX 10 mail.secure.domain.
3109 secure.domain. IN MX 50 mail.other.domain.
3111 then mail to user@secure.domain may go unencrypted to mail.other.domain.
3112 tls_rcpt can be used to address this problem.
3114 tls_rcpt is called before a RCPT TO: command is sent. The parameter is the
3115 current recipient. This ruleset is only defined if FEATURE(`access_db')
3116 is selected. A recipient address user@domain is looked up in the access
3117 map in four formats: TLS_Rcpt:user@domain, TLS_Rcpt:user@, TLS_Rcpt:domain,
3118 and TLS_Rcpt:; the first match is taken.
3120 The result of the lookups is then used to call the ruleset TLS_connection,
3121 which checks the requirement specified by the RHS in the access map against
3122 the actual parameters of the current TLS connection, esp. ${verify} and
3123 ${cipher_bits}. Legal RHSs in the access map are:
3125 VERIFY verification must have succeeded
3126 VERIFY:bits verification must have succeeded and ${cipher_bits} must
3127 be greater than or equal bits.
3128 ENCR:bits ${cipher_bits} must be greater than or equal bits.
3130 The RHS can optionally be prefixed by TEMP+ or PERM+ to select a temporary
3131 or permanent error. The default is a temporary error code (403 4.7.0)
3132 unless the macro TLS_PERM_ERR is set during generation of the .cf file.
3134 If a certain level of encryption is required, then it might also be
3135 possible that this level is provided by the security layer from a SASL
3136 algorithm, e.g., DIGEST-MD5.
3138 Furthermore, there can be a list of extensions added. Such a list
3139 starts with '+' and the items are separated by '++'. Allowed
3142 CN:name name must match ${cn_subject}
3143 CN ${server_name} must match ${cn_subject}
3144 CS:name name must match ${cert_subject}
3145 CI:name name must match ${cert_issuer}
3147 Example: e-mail sent to secure.example.com should only use an encrypted
3148 connection. E-mail received from hosts within the laptop.example.com domain
3149 should only be accepted if they have been authenticated. The host which
3150 receives e-mail for darth@endmail.org must present a cert that uses the
3151 CN smtp.endmail.org.
3153 TLS_Srv:secure.example.com ENCR:112
3154 TLS_Clt:laptop.example.com PERM+VERIFY:112
3155 TLS_Rcpt:darth@endmail.org ENCR:112+CN:smtp.endmail.org
3158 Disabling STARTTLS And Setting SMTP Server Features
3159 ---------------------------------------------------
3161 By default STARTTLS is used whenever possible. However, there are
3162 some broken MTAs that don't properly implement STARTTLS. To be able
3163 to send to (or receive from) those MTAs, the ruleset try_tls
3164 (srv_features) can be used that work together with the access map.
3165 Entries for the access map must be tagged with Try_TLS (Srv_Features)
3166 and refer to the hostname or IP address of the connecting system.
3167 A default case can be specified by using just the tag. For example,
3168 the following entries in the access map:
3170 Try_TLS:broken.server NO
3171 Srv_Features:my.domain v
3174 will turn off STARTTLS when sending to broken.server (or any host
3175 in that domain), and request a client certificate during the TLS
3176 handshake only for hosts in my.domain. The valid entries on the RHS
3177 for Srv_Features are listed in the Sendmail Installation and
3184 The Received: header reveals whether STARTTLS has been used. It contains an
3187 (version=${tls_version} cipher=${cipher} bits=${cipher_bits} verify=${verify})
3190 +---------------------+
3191 | SMTP AUTHENTICATION |
3192 +---------------------+
3194 The macros ${auth_authen}, ${auth_author}, and ${auth_type} can be
3195 used in anti-relay rulesets to allow relaying for those users that
3196 authenticated themselves. A very simple example is:
3199 R$* $: $&{auth_type}
3202 which checks whether a user has successfully authenticated using
3203 any available mechanism. Depending on the setup of the Cyrus SASL
3204 library, more sophisticated rulesets might be required, e.g.,
3207 R$* $: $&{auth_type} $| $&{auth_authen}
3208 RDIGEST-MD5 $| $+@$=w $# OK
3210 to allow relaying for users that authenticated using DIGEST-MD5
3211 and have an identity in the local domains.
3213 The ruleset trust_auth is used to determine whether a given AUTH=
3214 parameter (that is passed to this ruleset) should be trusted. This
3215 ruleset may make use of the other ${auth_*} macros. Only if the
3216 ruleset resolves to the error mailer, the AUTH= parameter is not
3217 trusted. A user supplied ruleset Local_trust_auth can be written
3218 to modify the default behavior, which only trust the AUTH=
3219 parameter if it is identical to the authenticated user.
3221 Per default, relaying is allowed for any user who authenticated
3222 via a "trusted" mechanism, i.e., one that is defined via
3223 TRUST_AUTH_MECH(`list of mechanisms')
3225 TRUST_AUTH_MECH(`KERBEROS_V4 DIGEST-MD5')
3227 If the selected mechanism provides a security layer the number of
3228 bits used for the key of the symmetric cipher is stored in the
3231 Providing SMTP AUTH Data when sendmail acts as Client
3232 -----------------------------------------------------
3234 If sendmail acts as client, it needs some information how to
3235 authenticate against another MTA. This information can be provided
3236 by the ruleset authinfo or by the option DefaultAuthInfo. The
3237 authinfo ruleset looks up {server_name} using the tag AuthInfo: in
3238 the access map. If no entry is found, {server_addr} is looked up
3239 in the same way and finally just the tag AuthInfo: to provide
3240 default values. Note: searches for domain parts or IP nets are
3241 only performed if the access map is used; if the authinfo feature
3242 is used then only up to three lookups are performed (two exact
3243 matches, one default).
3245 Note: If your daemon does client authentication when sending, and
3246 if it uses either PLAIN or LOGIN authentication, then you *must*
3247 prevent ordinary users from seeing verbose output. Do NOT install
3248 sendmail set-user-ID. Use PrivacyOptions to turn off verbose output
3249 ("goaway" works for this).
3251 Notice: the default configuration file causes the option DefaultAuthInfo
3252 to fail since the ruleset authinfo is in the .cf file. If you really
3253 want to use DefaultAuthInfo (it is deprecated) then you have to
3256 The RHS for an AuthInfo: entry in the access map should consists of a
3257 list of tokens, each of which has the form: "TDstring" (including
3258 the quotes). T is a tag which describes the item, D is a delimiter,
3259 either ':' for simple text or '=' for a base64 encoded string.
3260 Valid values for the tag are:
3262 U user (authorization) id
3266 M list of mechanisms delimited by spaces
3268 Example entries are:
3270 AuthInfo:other.dom "U:user" "I:user" "P:secret" "R:other.dom" "M:DIGEST-MD5"
3271 AuthInfo:host.more.dom "U:user" "P=c2VjcmV0"
3273 User id or authentication id must exist as well as the password. All
3274 other entries have default values. If one of user or authentication
3275 id is missing, the existing value is used for the missing item.
3276 If "R:" is not specified, realm defaults to $j. The list of mechanisms
3277 defaults to those specified by AuthMechanisms.
3279 Since this map contains sensitive information, either the access
3280 map must be unreadable by everyone but root (or the trusted user)
3281 or FEATURE(`authinfo') must be used which provides a separate map.
3282 Notice: It is not checked whether the map is actually
3283 group/world-unreadable, this is left to the user.
3285 +--------------------------------+
3286 | ADDING NEW MAILERS OR RULESETS |
3287 +--------------------------------+
3289 Sometimes you may need to add entirely new mailers or rulesets. They
3290 should be introduced with the constructs MAILER_DEFINITIONS and
3291 LOCAL_RULESETS respectively. For example:
3301 Local additions for the rulesets srv_features, try_tls, tls_rcpt,
3302 tls_client, and tls_server can be made using LOCAL_SRV_FEATURES,
3303 LOCAL_TRY_TLS, LOCAL_TLS_RCPT, LOCAL_TLS_CLIENT, and LOCAL_TLS_SERVER,
3304 respectively. For example, to add a local ruleset that decides
3305 whether to try STARTTLS in a sendmail client, use:
3310 Note: you don't need to add a name for the ruleset, it is implicitly
3311 defined by using the appropriate macro.
3314 +-------------------------+
3315 | ADDING NEW MAIL FILTERS |
3316 +-------------------------+
3318 Sendmail supports mail filters to filter incoming SMTP messages according
3319 to the "Sendmail Mail Filter API" documentation. These filters can be
3320 configured in your mc file using the two commands:
3322 MAIL_FILTER(`name', `equates')
3323 INPUT_MAIL_FILTER(`name', `equates')
3325 The first command, MAIL_FILTER(), simply defines a filter with the given
3326 name and equates. For example:
3328 MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3330 This creates the equivalent sendmail.cf entry:
3332 Xarchive, S=local:/var/run/archivesock, F=R
3334 The INPUT_MAIL_FILTER() command performs the same actions as MAIL_FILTER
3335 but also populates the m4 variable `confINPUT_MAIL_FILTERS' with the name
3336 of the filter such that the filter will actually be called by sendmail.
3338 For example, the two commands:
3340 INPUT_MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3341 INPUT_MAIL_FILTER(`spamcheck', `S=inet:2525@localhost, F=T')
3343 are equivalent to the three commands:
3345 MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3346 MAIL_FILTER(`spamcheck', `S=inet:2525@localhost, F=T')
3347 define(`confINPUT_MAIL_FILTERS', `archive, spamcheck')
3349 In general, INPUT_MAIL_FILTER() should be used unless you need to define
3350 more filters than you want to use for `confINPUT_MAIL_FILTERS'.
3352 Note that setting `confINPUT_MAIL_FILTERS' after any INPUT_MAIL_FILTER()
3353 commands will clear the list created by the prior INPUT_MAIL_FILTER()
3357 +-------------------------+
3358 | QUEUE GROUP DEFINITIONS |
3359 +-------------------------+
3361 In addition to the queue directory (which is the default queue group
3362 called "mqueue"), sendmail can deal with multiple queue groups, which
3363 are collections of queue directories with the same behaviour. Queue
3364 groups can be defined using the command:
3366 QUEUE_GROUP(`name', `equates')
3368 For details about queue groups, please see doc/op/op.{me,ps,txt}.
3370 +-------------------------------+
3371 | NON-SMTP BASED CONFIGURATIONS |
3372 +-------------------------------+
3374 These configuration files are designed primarily for use by
3375 SMTP-based sites. They may not be well tuned for UUCP-only or
3376 UUCP-primarily nodes (the latter is defined as a small local net
3377 connected to the rest of the world via UUCP). However, there is
3378 one hook to handle some special cases.
3380 You can define a ``smart host'' that understands a richer address syntax
3383 define(`SMART_HOST', `mailer:hostname')
3385 In this case, the ``mailer:'' defaults to "relay". Any messages that
3386 can't be handled using the usual UUCP rules are passed to this host.
3388 If you are on a local SMTP-based net that connects to the outside
3389 world via UUCP, you can use LOCAL_NET_CONFIG to add appropriate rules.
3392 define(`SMART_HOST', `uucp-new:uunet')
3394 R$* < @ $* .$m. > $* $#smtp $@ $2.$m. $: $1 < @ $2.$m. > $3
3396 This will cause all names that end in your domain name ($m) to be sent
3397 via SMTP; anything else will be sent via uucp-new (smart UUCP) to uunet.
3398 If you have FEATURE(`nocanonify'), you may need to omit the dots after
3399 the $m. If you are running a local DNS inside your domain which is
3400 not otherwise connected to the outside world, you probably want to
3403 define(`SMART_HOST', `smtp:fire.wall.com')
3405 R$* < @ $* . > $* $#smtp $@ $2. $: $1 < @ $2. > $3
3407 That is, send directly only to things you found in your DNS lookup;
3408 anything else goes through SMART_HOST.
3410 You may need to turn off the anti-spam rules in order to accept
3411 UUCP mail with FEATURE(`promiscuous_relay') and
3412 FEATURE(`accept_unresolvable_domains').
3419 Normally, the $j macro is automatically defined to be your fully
3420 qualified domain name (FQDN). Sendmail does this by getting your
3421 host name using gethostname and then calling gethostbyname on the
3422 result. For example, in some environments gethostname returns
3423 only the root of the host name (such as "foo"); gethostbyname is
3424 supposed to return the FQDN ("foo.bar.com"). In some (fairly rare)
3425 cases, gethostbyname may fail to return the FQDN. In this case
3426 you MUST define confDOMAIN_NAME to be your fully qualified domain
3427 name. This is usually done using:
3430 define(`confDOMAIN_NAME', `$w.$m')dnl
3433 +-----------------------------------+
3434 | ACCEPTING MAIL FOR MULTIPLE NAMES |
3435 +-----------------------------------+
3437 If your host is known by several different names, you need to augment
3438 class {w}. This is a list of names by which your host is known, and
3439 anything sent to an address using a host name in this list will be
3440 treated as local mail. You can do this in two ways: either create the
3441 file /etc/mail/local-host-names containing a list of your aliases (one per
3442 line), and use ``FEATURE(`use_cw_file')'' in the .mc file, or add
3443 ``LOCAL_DOMAIN(`alias.host.name')''. Be sure you use the fully-qualified
3444 name of the host, rather than a short name.
3446 If you want to have different address in different domains, take
3447 a look at the virtusertable feature, which is also explained at
3448 http://www.sendmail.org/virtual-hosting.html
3451 +--------------------+
3452 | USING MAILERTABLES |
3453 +--------------------+
3455 To use FEATURE(`mailertable'), you will have to create an external
3456 database containing the routing information for various domains.
3457 For example, a mailertable file in text format might be:
3459 .my.domain xnet:%1.my.domain
3460 uuhost1.my.domain uucp-new:uuhost1
3461 .bitnet smtp:relay.bit.net
3463 This should normally be stored in /etc/mail/mailertable. The actual
3464 database version of the mailertable is built using:
3466 makemap hash /etc/mail/mailertable < /etc/mail/mailertable
3468 The semantics are simple. Any LHS entry that does not begin with
3469 a dot matches the full host name indicated. LHS entries beginning
3470 with a dot match anything ending with that domain name (including
3471 the leading dot) -- that is, they can be thought of as having a
3472 leading ".+" regular expression pattern for a non-empty sequence of
3473 characters. Matching is done in order of most-to-least qualified
3474 -- for example, even though ".my.domain" is listed first in the
3475 above example, an entry of "uuhost1.my.domain" will match the second
3476 entry since it is more explicit. Note: e-mail to "user@my.domain"
3477 does not match any entry in the above table. You need to have
3480 my.domain esmtp:host.my.domain
3482 The RHS should always be a "mailer:host" pair. The mailer is the
3483 configuration name of a mailer (that is, an M line in the
3484 sendmail.cf file). The "host" will be the hostname passed to
3485 that mailer. In domain-based matches (that is, those with leading
3486 dots) the "%1" may be used to interpolate the wildcarded part of
3487 the host name. For example, the first line above sends everything
3488 addressed to "anything.my.domain" to that same host name, but using
3489 the (presumably experimental) xnet mailer.
3491 In some cases you may want to temporarily turn off MX records,
3492 particularly on gateways. For example, you may want to MX
3493 everything in a domain to one machine that then forwards it
3494 directly. To do this, you might use the DNS configuration:
3496 *.domain. IN MX 0 relay.machine
3498 and on relay.machine use the mailertable:
3500 .domain smtp:[gateway.domain]
3502 The [square brackets] turn off MX records for this host only.
3503 If you didn't do this, the mailertable would use the MX record
3504 again, which would give you an MX loop. Note that the use of
3505 wildcard MX records is almost always a bad idea. Please avoid
3506 using them if possible.
3509 +--------------------------------+
3510 | USING USERDB TO MAP FULL NAMES |
3511 +--------------------------------+
3513 The user database was not originally intended for mapping full names
3514 to login names (e.g., Eric.Allman => eric), but some people are using
3515 it that way. (it is recommended that you set up aliases for this
3516 purpose instead -- since you can specify multiple alias files, this
3517 is fairly easy.) The intent was to locate the default maildrop at
3518 a site, but allow you to override this by sending to a specific host.
3520 If you decide to set up the user database in this fashion, it is
3521 imperative that you not use FEATURE(`stickyhost') -- otherwise,
3522 e-mail sent to Full.Name@local.host.name will be rejected.
3524 To build the internal form of the user database, use:
3526 makemap btree /etc/mail/userdb < /etc/mail/userdb.txt
3528 As a general rule, it is an extremely bad idea to using full names
3529 as e-mail addresses, since they are not in any sense unique. For
3530 example, the UNIX software-development community has at least two
3531 well-known Peter Deutsches, and at one time Bell Labs had two
3532 Stephen R. Bournes with offices along the same hallway. Which one
3533 will be forced to suffer the indignity of being Stephen_R_Bourne_2?
3534 The less famous of the two, or the one that was hired later?
3536 Finger should handle full names (and be fuzzy). Mail should use
3537 handles, and not be fuzzy.
3540 +--------------------------------+
3541 | MISCELLANEOUS SPECIAL FEATURES |
3542 +--------------------------------+
3545 Sometimes it is convenient to merge configuration on a
3546 centralized mail machine, for example, to forward all
3547 root mail to a mail server. In this case it might be
3548 useful to be able to treat the root addresses as a class
3549 of addresses with subtle differences. You can do this
3550 using plussed users. For example, a client might include
3553 root: root+client1@server
3555 On the server, this will match an alias for "root+client1".
3556 If that is not found, the alias "root+*" will be tried,
3564 A lot of sendmail security comes down to you. Sendmail 8 is much
3565 more careful about checking for security problems than previous
3566 versions, but there are some things that you still need to watch
3569 * Make sure the aliases file is not writable except by trusted
3570 system personnel. This includes both the text and database
3573 * Make sure that other files that sendmail reads, such as the
3574 mailertable, are only writable by trusted system personnel.
3576 * The queue directory should not be world writable PARTICULARLY
3577 if your system allows "file giveaways" (that is, if a non-root
3578 user can chown any file they own to any other user).
3580 * If your system allows file giveaways, DO NOT create a publically
3581 writable directory for forward files. This will allow anyone
3582 to steal anyone else's e-mail. Instead, create a script that
3583 copies the .forward file from users' home directories once a
3584 night (if you want the non-NFS-mounted forward directory).
3586 * If your system allows file giveaways, you'll find that
3587 sendmail is much less trusting of :include: files -- in
3588 particular, you'll have to have /SENDMAIL/ANY/SHELL/ in
3589 /etc/shells before they will be trusted (that is, before
3590 files and programs listed in them will be honored).
3592 In general, file giveaways are a mistake -- if you can turn them
3596 +--------------------------------+
3597 | TWEAKING CONFIGURATION OPTIONS |
3598 +--------------------------------+
3600 There are a large number of configuration options that don't normally
3601 need to be changed. However, if you feel you need to tweak them,
3602 you can define the following M4 variables. Note that some of these
3603 variables require formats that are defined in RFC 2821 or RFC 2822.
3604 Before changing them you need to make sure you do not violate those
3605 (and other relevant) RFCs.
3607 This list is shown in four columns: the name you define, the default
3608 value for that definition, the option or macro that is affected
3609 (either Ox for an option or Dx for a macro), and a brief description.
3610 Greater detail of the semantics can be found in the Installation
3611 and Operations Guide.
3613 Some options are likely to be deprecated in future versions -- that is,
3614 the option is only included to provide back-compatibility. These are
3617 Remember that these options are M4 variables, and hence may need to
3618 be quoted. In particular, arguments with commas will usually have to
3619 be ``double quoted, like this phrase'' to avoid having the comma
3620 confuse things. This is common for alias file definitions and for
3623 M4 Variable Name Configuration [Default] & Description
3624 ================ ============= =======================
3625 confMAILER_NAME $n macro [MAILER-DAEMON] The sender name used
3626 for internally generated outgoing
3628 confDOMAIN_NAME $j macro If defined, sets $j. This should
3629 only be done if your system cannot
3630 determine your local domain name,
3631 and then it should be set to
3632 $w.Foo.COM, where Foo.COM is your
3634 confCF_VERSION $Z macro If defined, this is appended to the
3635 configuration version name.
3636 confLDAP_CLUSTER ${sendmailMTACluster} macro
3637 If defined, this is the LDAP
3638 cluster to use for LDAP searches
3639 as described above in ``USING LDAP
3640 FOR ALIASES, MAPS, AND CLASSES''.
3641 confFROM_HEADER From: [$?x$x <$g>$|$g$.] The format of an
3642 internally generated From: address.
3643 confRECEIVED_HEADER Received:
3644 [$?sfrom $s $.$?_($?s$|from $.$_)
3645 $.$?{auth_type}(authenticated)
3646 $.by $j ($v/$Z)$?r with $r$. id $i$?u
3649 The format of the Received: header
3650 in messages passed through this host.
3651 It is unwise to try to change this.
3652 confMESSAGEID_HEADER Message-Id: [<$t.$i@$j>] The format of an
3653 internally generated Message-Id:
3655 confCW_FILE Fw class [/etc/mail/local-host-names] Name
3656 of file used to get the local
3657 additions to class {w} (local host
3659 confCT_FILE Ft class [/etc/mail/trusted-users] Name of
3660 file used to get the local additions
3661 to class {t} (trusted users).
3662 confCR_FILE FR class [/etc/mail/relay-domains] Name of
3663 file used to get the local additions
3664 to class {R} (hosts allowed to relay).
3665 confTRUSTED_USERS Ct class [no default] Names of users to add to
3666 the list of trusted users. This list
3667 always includes root, uucp, and daemon.
3668 See also FEATURE(`use_ct_file').
3669 confTRUSTED_USER TrustedUser [no default] Trusted user for file
3670 ownership and starting the daemon.
3671 Not to be confused with
3672 confTRUSTED_USERS (see above).
3673 confSMTP_MAILER - [esmtp] The mailer name used when
3674 SMTP connectivity is required.
3675 One of "smtp", "smtp8",
3676 "esmtp", or "dsmtp".
3677 confUUCP_MAILER - [uucp-old] The mailer to be used by
3678 default for bang-format recipient
3679 addresses. See also discussion of
3680 class {U}, class {Y}, and class {Z}
3681 in the MAILER(`uucp') section.
3682 confLOCAL_MAILER - [local] The mailer name used when
3683 local connectivity is required.
3684 Almost always "local".
3685 confRELAY_MAILER - [relay] The default mailer name used
3686 for relaying any mail (e.g., to a
3687 BITNET_RELAY, a SMART_HOST, or
3688 whatever). This can reasonably be
3689 "uucp-new" if you are on a
3690 UUCP-connected site.
3691 confSEVEN_BIT_INPUT SevenBitInput [False] Force input to seven bits?
3692 confEIGHT_BIT_HANDLING EightBitMode [pass8] 8-bit data handling
3693 confALIAS_WAIT AliasWait [10m] Time to wait for alias file
3694 rebuild until you get bored and
3695 decide that the apparently pending
3697 confMIN_FREE_BLOCKS MinFreeBlocks [100] Minimum number of free blocks on
3698 queue filesystem to accept SMTP mail.
3699 (Prior to 8.7 this was minfree/maxsize,
3700 where minfree was the number of free
3701 blocks and maxsize was the maximum
3702 message size. Use confMAX_MESSAGE_SIZE
3703 for the second value now.)
3704 confMAX_MESSAGE_SIZE MaxMessageSize [infinite] The maximum size of messages
3705 that will be accepted (in bytes).
3706 confBLANK_SUB BlankSub [.] Blank (space) substitution
3708 confCON_EXPENSIVE HoldExpensive [False] Avoid connecting immediately
3709 to mailers marked expensive.
3710 confCHECKPOINT_INTERVAL CheckpointInterval
3711 [10] Checkpoint queue files every N
3713 confDELIVERY_MODE DeliveryMode [background] Default delivery mode.
3714 confERROR_MODE ErrorMode [print] Error message mode.
3715 confERROR_MESSAGE ErrorHeader [undefined] Error message header/file.
3716 confSAVE_FROM_LINES SaveFromLine Save extra leading From_ lines.
3717 confTEMP_FILE_MODE TempFileMode [0600] Temporary file mode.
3718 confMATCH_GECOS MatchGECOS [False] Match GECOS field.
3719 confMAX_HOP MaxHopCount [25] Maximum hop count.
3720 confIGNORE_DOTS* IgnoreDots [False; always False in -bs or -bd
3721 mode] Ignore dot as terminator for
3723 confBIND_OPTS ResolverOptions [undefined] Default options for DNS
3725 confMIME_FORMAT_ERRORS* SendMimeErrors [True] Send error messages as MIME-
3726 encapsulated messages per RFC 1344.
3727 confFORWARD_PATH ForwardPath [$z/.forward.$w:$z/.forward]
3728 The colon-separated list of places to
3729 search for .forward files. N.B.: see
3730 the Security Notes section.
3731 confMCI_CACHE_SIZE ConnectionCacheSize
3732 [2] Size of open connection cache.
3733 confMCI_CACHE_TIMEOUT ConnectionCacheTimeout
3734 [5m] Open connection cache timeout.
3735 confHOST_STATUS_DIRECTORY HostStatusDirectory
3736 [undefined] If set, host status is kept
3737 on disk between sendmail runs in the
3738 named directory tree. This need not be
3739 a full pathname, in which case it is
3740 interpreted relative to the queue
3742 confSINGLE_THREAD_DELIVERY SingleThreadDelivery
3743 [False] If this option and the
3744 HostStatusDirectory option are both
3745 set, single thread deliveries to other
3746 hosts. That is, don't allow any two
3747 sendmails on this host to connect
3748 simultaneously to any other single
3749 host. This can slow down delivery in
3750 some cases, in particular since a
3751 cached but otherwise idle connection
3752 to a host will prevent other sendmails
3753 from connecting to the other host.
3754 confUSE_ERRORS_TO* UseErrorsTo [False] Use the Errors-To: header to
3755 deliver error messages. This should
3756 not be necessary because of general
3757 acceptance of the envelope/header
3759 confLOG_LEVEL LogLevel [9] Log level.
3760 confME_TOO MeToo [True] Include sender in group
3761 expansions. This option is
3762 deprecated and will be removed from
3764 confCHECK_ALIASES CheckAliases [False] Check RHS of aliases when
3765 running newaliases. Since this does
3766 DNS lookups on every address, it can
3767 slow down the alias rebuild process
3768 considerably on large alias files.
3769 confOLD_STYLE_HEADERS* OldStyleHeaders [True] Assume that headers without
3770 special chars are old style.
3771 confPRIVACY_FLAGS PrivacyOptions [authwarnings] Privacy flags.
3772 confCOPY_ERRORS_TO PostmasterCopy [undefined] Address for additional
3773 copies of all error messages.
3774 confQUEUE_FACTOR QueueFactor [600000] Slope of queue-only function.
3775 confQUEUE_FILE_MODE QueueFileMode [undefined] Default permissions for
3776 queue files (octal). If not set,
3777 sendmail uses 0600 unless its real
3778 and effective uid are different in
3779 which case it uses 0644.
3780 confDONT_PRUNE_ROUTES DontPruneRoutes [False] Don't prune down route-addr
3781 syntax addresses to the minimum
3783 confSAFE_QUEUE* SuperSafe [True] Commit all messages to disk
3785 confTO_INITIAL Timeout.initial [5m] The timeout waiting for a response
3786 on the initial connect.
3787 confTO_CONNECT Timeout.connect [0] The timeout waiting for an initial
3788 connect() to complete. This can only
3789 shorten connection timeouts; the kernel
3790 silently enforces an absolute maximum
3791 (which varies depending on the system).
3792 confTO_ICONNECT Timeout.iconnect
3793 [undefined] Like Timeout.connect, but
3794 applies only to the very first attempt
3795 to connect to a host in a message.
3796 This allows a single very fast pass
3797 followed by more careful delivery
3798 attempts in the future.
3799 confTO_ACONNECT Timeout.aconnect
3800 [0] The overall timeout waiting for
3801 all connection for a single delivery
3802 attempt to succeed. If 0, no overall
3804 confTO_HELO Timeout.helo [5m] The timeout waiting for a response
3805 to a HELO or EHLO command.
3806 confTO_MAIL Timeout.mail [10m] The timeout waiting for a
3807 response to the MAIL command.
3808 confTO_RCPT Timeout.rcpt [1h] The timeout waiting for a response
3809 to the RCPT command.
3810 confTO_DATAINIT Timeout.datainit
3811 [5m] The timeout waiting for a 354
3812 response from the DATA command.
3813 confTO_DATABLOCK Timeout.datablock
3814 [1h] The timeout waiting for a block
3816 confTO_DATAFINAL Timeout.datafinal
3817 [1h] The timeout waiting for a response
3818 to the final "." that terminates a
3820 confTO_RSET Timeout.rset [5m] The timeout waiting for a response
3821 to the RSET command.
3822 confTO_QUIT Timeout.quit [2m] The timeout waiting for a response
3823 to the QUIT command.
3824 confTO_MISC Timeout.misc [2m] The timeout waiting for a response
3825 to other SMTP commands.
3826 confTO_COMMAND Timeout.command [1h] In server SMTP, the timeout
3827 waiting for a command to be issued.
3828 confTO_IDENT Timeout.ident [5s] The timeout waiting for a
3829 response to an IDENT query.
3830 confTO_FILEOPEN Timeout.fileopen
3831 [60s] The timeout waiting for a file
3832 (e.g., :include: file) to be opened.
3833 confTO_LHLO Timeout.lhlo [2m] The timeout waiting for a response
3834 to an LMTP LHLO command.
3835 confTO_AUTH Timeout.auth [10m] The timeout waiting for a
3836 response in an AUTH dialogue.
3837 confTO_STARTTLS Timeout.starttls
3838 [1h] The timeout waiting for a
3839 response to an SMTP STARTTLS command.
3840 confTO_CONTROL Timeout.control
3841 [2m] The timeout for a complete
3842 control socket transaction to complete.
3843 confTO_QUEUERETURN Timeout.queuereturn
3844 [5d] The timeout before a message is
3845 returned as undeliverable.
3846 confTO_QUEUERETURN_NORMAL
3847 Timeout.queuereturn.normal
3848 [undefined] As above, for normal
3850 confTO_QUEUERETURN_URGENT
3851 Timeout.queuereturn.urgent
3852 [undefined] As above, for urgent
3854 confTO_QUEUERETURN_NONURGENT
3855 Timeout.queuereturn.non-urgent
3856 [undefined] As above, for non-urgent
3857 (low) priority messages.
3858 confTO_QUEUERETURN_DSN
3859 Timeout.queuereturn.dsn
3860 [undefined] As above, for delivery
3861 status notification messages.
3862 confTO_QUEUEWARN Timeout.queuewarn
3863 [4h] The timeout before a warning
3864 message is sent to the sender telling
3865 them that the message has been
3867 confTO_QUEUEWARN_NORMAL Timeout.queuewarn.normal
3868 [undefined] As above, for normal
3870 confTO_QUEUEWARN_URGENT Timeout.queuewarn.urgent
3871 [undefined] As above, for urgent
3873 confTO_QUEUEWARN_NONURGENT
3874 Timeout.queuewarn.non-urgent
3875 [undefined] As above, for non-urgent
3876 (low) priority messages.
3877 confTO_QUEUEWARN_DSN
3878 Timeout.queuewarn.dsn
3879 [undefined] As above, for delivery
3880 status notification messages.
3881 confTO_HOSTSTATUS Timeout.hoststatus
3882 [30m] How long information about host
3883 statuses will be maintained before it
3884 is considered stale and the host should
3885 be retried. This applies both within
3886 a single queue run and to persistent
3887 information (see below).
3888 confTO_RESOLVER_RETRANS Timeout.resolver.retrans
3889 [varies] Sets the resolver's
3890 retransmission time interval (in
3892 Timeout.resolver.retrans.first and
3893 Timeout.resolver.retrans.normal.
3894 confTO_RESOLVER_RETRANS_FIRST Timeout.resolver.retrans.first
3895 [varies] Sets the resolver's
3896 retransmission time interval (in
3897 seconds) for the first attempt to
3899 confTO_RESOLVER_RETRANS_NORMAL Timeout.resolver.retrans.normal
3900 [varies] Sets the resolver's
3901 retransmission time interval (in
3902 seconds) for all resolver lookups
3903 except the first delivery attempt.
3904 confTO_RESOLVER_RETRY Timeout.resolver.retry
3905 [varies] Sets the number of times
3906 to retransmit a resolver query.
3908 Timeout.resolver.retry.first and
3909 Timeout.resolver.retry.normal.
3910 confTO_RESOLVER_RETRY_FIRST Timeout.resolver.retry.first
3911 [varies] Sets the number of times
3912 to retransmit a resolver query for
3913 the first attempt to deliver a
3915 confTO_RESOLVER_RETRY_NORMAL Timeout.resolver.retry.normal
3916 [varies] Sets the number of times
3917 to retransmit a resolver query for
3918 all resolver lookups except the
3919 first delivery attempt.
3920 confTIME_ZONE TimeZoneSpec [USE_SYSTEM] Time zone info -- can be
3921 USE_SYSTEM to use the system's idea,
3922 USE_TZ to use the user's TZ envariable,
3923 or something else to force that value.
3924 confDEF_USER_ID DefaultUser [1:1] Default user id.
3925 confUSERDB_SPEC UserDatabaseSpec
3926 [undefined] User database
3928 confFALLBACK_MX FallbackMXhost [undefined] Fallback MX host.
3929 confFALLBACK_SMARTHOST FallbackSmartHost
3930 [undefined] Fallback smart host.
3931 confTRY_NULL_MX_LIST TryNullMXList [False] If this host is the best MX
3932 for a host and other arrangements
3933 haven't been made, try connecting
3934 to the host directly; normally this
3935 would be a config error.
3936 confQUEUE_LA QueueLA [varies] Load average at which
3937 queue-only function kicks in.
3938 Default values is (8 * numproc)
3939 where numproc is the number of
3940 processors online (if that can be
3942 confREFUSE_LA RefuseLA [varies] Load average at which
3943 incoming SMTP connections are
3944 refused. Default values is (12 *
3945 numproc) where numproc is the
3946 number of processors online (if
3947 that can be determined).
3948 confREJECT_LOG_INTERVAL RejectLogInterval [3h] Log interval when
3949 refusing connections for this long.
3950 confDELAY_LA DelayLA [0] Load average at which sendmail
3951 will sleep for one second on most
3952 SMTP commands and before accepting
3953 connections. 0 means no limit.
3954 confMAX_ALIAS_RECURSION MaxAliasRecursion
3955 [10] Maximum depth of alias recursion.
3956 confMAX_DAEMON_CHILDREN MaxDaemonChildren
3957 [undefined] The maximum number of
3958 children the daemon will permit. After
3959 this number, connections will be
3960 rejected. If not set or <= 0, there is
3962 confMAX_HEADERS_LENGTH MaxHeadersLength
3963 [32768] Maximum length of the sum
3965 confMAX_MIME_HEADER_LENGTH MaxMimeHeaderLength
3966 [undefined] Maximum length of
3967 certain MIME header field values.
3968 confCONNECTION_RATE_THROTTLE ConnectionRateThrottle
3969 [undefined] The maximum number of
3970 connections permitted per second per
3971 daemon. After this many connections
3972 are accepted, further connections
3973 will be delayed. If not set or <= 0,
3975 confCONNECTION_RATE_WINDOW_SIZE ConnectionRateWindowSize
3976 [60s] Define the length of the
3977 interval for which the number of
3978 incoming connections is maintained.
3979 confWORK_RECIPIENT_FACTOR
3980 RecipientFactor [30000] Cost of each recipient.
3981 confSEPARATE_PROC ForkEachJob [False] Run all deliveries in a
3983 confWORK_CLASS_FACTOR ClassFactor [1800] Priority multiplier for class.
3984 confWORK_TIME_FACTOR RetryFactor [90000] Cost of each delivery attempt.
3985 confQUEUE_SORT_ORDER QueueSortOrder [Priority] Queue sort algorithm:
3986 Priority, Host, Filename, Random,
3987 Modification, or Time.
3988 confMIN_QUEUE_AGE MinQueueAge [0] The minimum amount of time a job
3989 must sit in the queue between queue
3990 runs. This allows you to set the
3991 queue run interval low for better
3992 responsiveness without trying all
3994 confDEF_CHAR_SET DefaultCharSet [unknown-8bit] When converting
3995 unlabeled 8 bit input to MIME, the
3996 character set to use by default.
3997 confSERVICE_SWITCH_FILE ServiceSwitchFile
3998 [/etc/mail/service.switch] The file
3999 to use for the service switch on
4000 systems that do not have a
4001 system-defined switch.
4002 confHOSTS_FILE HostsFile [/etc/hosts] The file to use when doing
4003 "file" type access of hosts names.
4004 confDIAL_DELAY DialDelay [0s] If a connection fails, wait this
4005 long and try again. Zero means "don't
4006 retry". This is to allow "dial on
4007 demand" connections to have enough time
4008 to complete a connection.
4009 confNO_RCPT_ACTION NoRecipientAction
4010 [none] What to do if there are no legal
4011 recipient fields (To:, Cc: or Bcc:)
4012 in the message. Legal values can
4013 be "none" to just leave the
4014 nonconforming message as is, "add-to"
4015 to add a To: header with all the
4016 known recipients (which may expose
4017 blind recipients), "add-apparently-to"
4018 to do the same but use Apparently-To:
4019 instead of To: (strongly discouraged
4020 in accordance with IETF standards),
4021 "add-bcc" to add an empty Bcc:
4022 header, or "add-to-undisclosed" to
4024 ``To: undisclosed-recipients:;''.
4025 confSAFE_FILE_ENV SafeFileEnvironment
4026 [undefined] If set, sendmail will do a
4027 chroot() into this directory before
4029 confCOLON_OK_IN_ADDR ColonOkInAddr [True unless Configuration Level > 6]
4030 If set, colons are treated as a regular
4031 character in addresses. If not set,
4032 they are treated as the introducer to
4033 the RFC 822 "group" syntax. Colons are
4034 handled properly in route-addrs. This
4035 option defaults on for V5 and lower
4036 configuration files.
4037 confMAX_QUEUE_RUN_SIZE MaxQueueRunSize [0] If set, limit the maximum size of
4038 any given queue run to this number of
4039 entries. Essentially, this will stop
4040 reading each queue directory after this
4041 number of entries are reached; it does
4042 _not_ pick the highest priority jobs,
4043 so this should be as large as your
4044 system can tolerate. If not set, there
4046 confMAX_QUEUE_CHILDREN MaxQueueChildren
4047 [undefined] Limits the maximum number
4048 of concurrent queue runners active.
4049 This is to keep system resources used
4050 within a reasonable limit. Relates to
4051 Queue Groups and ForkEachJob.
4052 confMAX_RUNNERS_PER_QUEUE MaxRunnersPerQueue
4053 [1] Only active when MaxQueueChildren
4054 defined. Controls the maximum number
4055 of queue runners (aka queue children)
4056 active at the same time in a work
4057 group. See also MaxQueueChildren.
4058 confDONT_EXPAND_CNAMES DontExpandCnames
4059 [False] If set, $[ ... $] lookups that
4060 do DNS based lookups do not expand
4061 CNAME records. This currently violates
4062 the published standards, but the IETF
4063 seems to be moving toward legalizing
4064 this. For example, if "FTP.Foo.ORG"
4065 is a CNAME for "Cruft.Foo.ORG", then
4066 with this option set a lookup of
4067 "FTP" will return "FTP.Foo.ORG"; if
4068 clear it returns "Cruft.FOO.ORG". N.B.
4069 you may not see any effect until your
4070 downstream neighbors stop doing CNAME
4072 confFROM_LINE UnixFromLine [From $g $d] The From_ line used
4073 when sending to files or programs.
4074 confSINGLE_LINE_FROM_HEADER SingleLineFromHeader
4075 [False] From: lines that have
4076 embedded newlines are unwrapped
4078 confALLOW_BOGUS_HELO AllowBogusHELO [False] Allow HELO SMTP command that
4079 does not include a host name.
4080 confMUST_QUOTE_CHARS MustQuoteChars [.'] Characters to be quoted in a full
4081 name phrase (@,;:\()[] are automatic).
4082 confOPERATORS OperatorChars [.:%@!^/[]+] Address operator
4084 confSMTP_LOGIN_MSG SmtpGreetingMessage
4085 [$j Sendmail $v/$Z; $b]
4086 The initial (spontaneous) SMTP
4087 greeting message. The word "ESMTP"
4088 will be inserted between the first and
4089 second words to convince other
4090 sendmails to try to speak ESMTP.
4091 confDONT_INIT_GROUPS DontInitGroups [False] If set, the initgroups(3)
4092 routine will never be invoked. You
4093 might want to do this if you are
4094 running NIS and you have a large group
4095 map, since this call does a sequential
4096 scan of the map; in a large site this
4097 can cause your ypserv to run
4098 essentially full time. If you set
4099 this, agents run on behalf of users
4100 will only have their primary
4101 (/etc/passwd) group permissions.
4102 confUNSAFE_GROUP_WRITES UnsafeGroupWrites
4103 [True] If set, group-writable
4104 :include: and .forward files are
4105 considered "unsafe", that is, programs
4106 and files cannot be directly referenced
4107 from such files. World-writable files
4108 are always considered unsafe.
4109 Notice: this option is deprecated and
4110 will be removed in future versions;
4111 Set GroupWritableForwardFileSafe
4112 and GroupWritableIncludeFileSafe in
4113 DontBlameSendmail if required.
4114 confCONNECT_ONLY_TO ConnectOnlyTo [undefined] override connection
4115 address (for testing).
4116 confCONTROL_SOCKET_NAME ControlSocketName
4117 [undefined] Control socket for daemon
4119 confDOUBLE_BOUNCE_ADDRESS DoubleBounceAddress
4120 [postmaster] If an error occurs when
4121 sending an error message, send that
4122 "double bounce" error message to this
4123 address. If it expands to an empty
4124 string, double bounces are dropped.
4125 confSOFT_BOUNCE SoftBounce [False] If set, issue temporary errors
4126 (4xy) instead of permanent errors
4127 (5xy). This can be useful during
4128 testing of a new configuration to
4129 avoid erroneous bouncing of mails.
4130 confDEAD_LETTER_DROP DeadLetterDrop [undefined] Filename to save bounce
4131 messages which could not be returned
4132 to the user or sent to postmaster.
4133 If not set, the queue file will
4135 confRRT_IMPLIES_DSN RrtImpliesDsn [False] Return-Receipt-To: header
4136 implies DSN request.
4137 confRUN_AS_USER RunAsUser [undefined] If set, become this user
4138 when reading and delivering mail.
4139 Causes all file reads (e.g., .forward
4140 and :include: files) to be done as
4141 this user. Also, all programs will
4142 be run as this user, and all output
4143 files will be written as this user.
4144 confMAX_RCPTS_PER_MESSAGE MaxRecipientsPerMessage
4145 [infinite] If set, allow no more than
4146 the specified number of recipients in
4147 an SMTP envelope. Further recipients
4148 receive a 452 error code (i.e., they
4149 are deferred for the next delivery
4151 confBAD_RCPT_THROTTLE BadRcptThrottle [infinite] If set and the specified
4152 number of recipients in a single SMTP
4153 transaction have been rejected, sleep
4154 for one second after each subsequent
4155 RCPT command in that transaction.
4156 confDONT_PROBE_INTERFACES DontProbeInterfaces
4157 [False] If set, sendmail will _not_
4158 insert the names and addresses of any
4159 local interfaces into class {w}
4160 (list of known "equivalent" addresses).
4161 If you set this, you must also include
4162 some support for these addresses (e.g.,
4163 in a mailertable entry) -- otherwise,
4164 mail to addresses in this list will
4165 bounce with a configuration error.
4166 If set to "loopback" (without
4167 quotes), sendmail will skip
4168 loopback interfaces (e.g., "lo0").
4169 confPID_FILE PidFile [system dependent] Location of pid
4171 confPROCESS_TITLE_PREFIX ProcessTitlePrefix
4172 [undefined] Prefix string for the
4173 process title shown on 'ps' listings.
4174 confDONT_BLAME_SENDMAIL DontBlameSendmail
4175 [safe] Override sendmail's file
4176 safety checks. This will definitely
4177 compromise system security and should
4178 not be used unless absolutely
4180 confREJECT_MSG - [550 Access denied] The message
4181 given if the access database contains
4182 REJECT in the value portion.
4183 confRELAY_MSG - [550 Relaying denied] The message
4184 given if an unauthorized relaying
4185 attempt is rejected.
4186 confDF_BUFFER_SIZE DataFileBufferSize
4187 [4096] The maximum size of a
4188 memory-buffered data (df) file
4189 before a disk-based file is used.
4190 confXF_BUFFER_SIZE XScriptFileBufferSize
4191 [4096] The maximum size of a
4192 memory-buffered transcript (xf)
4193 file before a disk-based file is
4195 confAUTH_MECHANISMS AuthMechanisms [GSSAPI KERBEROS_V4 DIGEST-MD5
4196 CRAM-MD5] List of authentication
4197 mechanisms for AUTH (separated by
4198 spaces). The advertised list of
4199 authentication mechanisms will be the
4200 intersection of this list and the list
4201 of available mechanisms as determined
4202 by the Cyrus SASL library.
4203 confAUTH_REALM AuthRealm [undefined] The authentication realm
4204 that is passed to the Cyrus SASL
4205 library. If no realm is specified,
4207 confDEF_AUTH_INFO DefaultAuthInfo [undefined] Name of file that contains
4208 authentication information for
4209 outgoing connections. This file must
4210 contain the user id, the authorization
4211 id, the password (plain text), the
4212 realm to use, and the list of
4213 mechanisms to try, each on a separate
4214 line and must be readable by root (or
4215 the trusted user) only. If no realm
4216 is specified, $j is used. If no
4217 mechanisms are given in the file,
4218 AuthMechanisms is used. Notice: this
4219 option is deprecated and will be
4220 removed in future versions; it doesn't
4221 work for the MSP since it can't read
4222 the file. Use the authinfo ruleset
4223 instead. See also the section SMTP
4225 confAUTH_OPTIONS AuthOptions [undefined] If this option is 'A'
4226 then the AUTH= parameter for the
4227 MAIL FROM command is only issued
4228 when authentication succeeded.
4229 See doc/op/op.me for more options
4231 confAUTH_MAX_BITS AuthMaxBits [INT_MAX] Limit the maximum encryption
4232 strength for the security layer in
4233 SMTP AUTH (SASL). Default is
4234 essentially unlimited.
4235 confTLS_SRV_OPTIONS TLSSrvOptions If this option is 'V' no client
4236 verification is performed, i.e.,
4237 the server doesn't ask for a
4239 confLDAP_DEFAULT_SPEC LDAPDefaultSpec [undefined] Default map
4240 specification for LDAP maps. The
4241 value should only contain LDAP
4242 specific settings such as "-h host
4243 -p port -d bindDN", etc. The
4244 settings will be used for all LDAP
4245 maps unless they are specified in
4246 the individual map specification
4248 confCACERT_PATH CACertPath [undefined] Path to directory
4250 confCACERT CACertFile [undefined] File containing one CA
4252 confSERVER_CERT ServerCertFile [undefined] File containing the
4253 cert of the server, i.e., this cert
4254 is used when sendmail acts as
4256 confSERVER_KEY ServerKeyFile [undefined] File containing the
4257 private key belonging to the server
4259 confCLIENT_CERT ClientCertFile [undefined] File containing the
4260 cert of the client, i.e., this cert
4261 is used when sendmail acts as
4263 confCLIENT_KEY ClientKeyFile [undefined] File containing the
4264 private key belonging to the client
4266 confCRL CRLFile [undefined] File containing certificate
4267 revocation status, useful for X.509v3
4268 authentication. Note that CRL requires
4269 at least OpenSSL version 0.9.7.
4270 confDH_PARAMETERS DHParameters [undefined] File containing the
4272 confRAND_FILE RandFile [undefined] File containing random
4273 data (use prefix file:) or the
4274 name of the UNIX socket if EGD is
4275 used (use prefix egd:). STARTTLS
4276 requires this option if the compile
4277 flag HASURANDOM is not set (see
4279 confNICE_QUEUE_RUN NiceQueueRun [undefined] If set, the priority of
4280 queue runners is set the given value
4282 confDIRECT_SUBMISSION_MODIFIERS DirectSubmissionModifiers
4283 [undefined] Defines {daemon_flags}
4284 for direct submissions.
4285 confUSE_MSP UseMSP [undefined] Use as mail submission
4286 program, see sendmail/SECURITY.
4287 confDELIVER_BY_MIN DeliverByMin [0] Minimum time for Deliver By
4288 SMTP Service Extension (RFC 2852).
4289 confREQUIRES_DIR_FSYNC RequiresDirfsync [true] RequiresDirfsync can
4290 be used to turn off the compile time
4291 flag REQUIRES_DIR_FSYNC at runtime.
4292 See sendmail/README for details.
4293 confSHARED_MEMORY_KEY SharedMemoryKey [0] Key for shared memory.
4294 confSHARED_MEMORY_KEY_FILE
4296 [undefined] File where the
4297 automatically selected key for
4298 shared memory is stored.
4299 confFAST_SPLIT FastSplit [1] If set to a value greater than
4300 zero, the initial MX lookups on
4301 addresses is suppressed when they
4302 are sorted which may result in
4303 faster envelope splitting. If the
4304 mail is submitted directly from the
4305 command line, then the value also
4306 limits the number of processes to
4307 deliver the envelopes.
4308 confMAILBOX_DATABASE MailboxDatabase [pw] Type of lookup to find
4309 information about local mailboxes.
4310 confDEQUOTE_OPTS - [empty] Additional options for the
4312 confMAX_NOOP_COMMANDS MaxNOOPCommands [20] Maximum number of "useless"
4313 commands before the SMTP server
4314 will slow down responding.
4315 confHELO_NAME HeloName If defined, use as name for EHLO/HELO
4316 command (instead of $j).
4317 confINPUT_MAIL_FILTERS InputMailFilters
4318 A comma separated list of filters
4319 which determines which filters and
4320 the invocation sequence are
4321 contacted for incoming SMTP
4322 messages. If none are set, no
4323 filters will be contacted.
4324 confMILTER_LOG_LEVEL Milter.LogLevel [9] Log level for input mail filter
4325 actions, defaults to LogLevel.
4326 confMILTER_MACROS_CONNECT Milter.macros.connect
4327 [j, _, {daemon_name}, {if_name},
4328 {if_addr}] Macros to transmit to
4329 milters when a session connection
4331 confMILTER_MACROS_HELO Milter.macros.helo
4332 [{tls_version}, {cipher},
4333 {cipher_bits}, {cert_subject},
4334 {cert_issuer}] Macros to transmit to
4335 milters after HELO/EHLO command.
4336 confMILTER_MACROS_ENVFROM Milter.macros.envfrom
4337 [i, {auth_type}, {auth_authen},
4338 {auth_ssf}, {auth_author},
4339 {mail_mailer}, {mail_host},
4340 {mail_addr}] Macros to transmit to
4341 milters after MAIL FROM command.
4342 confMILTER_MACROS_ENVRCPT Milter.macros.envrcpt
4343 [{rcpt_mailer}, {rcpt_host},
4344 {rcpt_addr}] Macros to transmit to
4345 milters after RCPT TO command.
4346 confMILTER_MACROS_EOM Milter.macros.eom
4347 [{msg_id}] Macros to transmit to
4348 milters after the terminating
4349 DATA '.' is received.
4350 confMILTER_MACROS_EOH Milter.macros.eoh
4351 Macros to transmit to milters
4352 after the end of headers.
4353 confMILTER_MACROS_DATA Milter.macros.data
4354 Macros to transmit to milters
4355 after DATA command is received.
4358 See also the description of OSTYPE for some parameters that can be
4359 tweaked (generally pathnames to mailers).
4361 ClientPortOptions and DaemonPortOptions are special cases since multiple
4362 clients/daemons can be defined. This can be done via
4364 CLIENT_OPTIONS(`field1=value1,field2=value2,...')
4365 DAEMON_OPTIONS(`field1=value1,field2=value2,...')
4367 Note that multiple CLIENT_OPTIONS() commands (and therefore multiple
4368 ClientPortOptions settings) are allowed in order to give settings for each
4369 protocol family (e.g., one for Family=inet and one for Family=inet6). A
4370 restriction placed on one family only affects outgoing connections on that
4373 If DAEMON_OPTIONS is not used, then the default is
4375 DAEMON_OPTIONS(`Port=smtp, Name=MTA')
4376 DAEMON_OPTIONS(`Port=587, Name=MSA, M=E')
4378 If you use one DAEMON_OPTIONS macro, it will alter the parameters
4379 of the first of these. The second will still be defaulted; it
4380 represents a "Message Submission Agent" (MSA) as defined by RFC
4381 2476 (see below). To turn off the default definition for the MSA,
4382 use FEATURE(`no_default_msa') (see also FEATURES). If you use
4383 additional DAEMON_OPTIONS macros, they will add additional daemons.
4385 Example 1: To change the port for the SMTP listener, while
4386 still using the MSA default, use
4387 DAEMON_OPTIONS(`Port=925, Name=MTA')
4389 Example 2: To change the port for the MSA daemon, while still
4390 using the default SMTP port, use
4391 FEATURE(`no_default_msa')
4392 DAEMON_OPTIONS(`Name=MTA')
4393 DAEMON_OPTIONS(`Port=987, Name=MSA, M=E')
4395 Note that if the first of those DAEMON_OPTIONS lines were omitted, then
4396 there would be no listener on the standard SMTP port.
4398 Example 3: To listen on both IPv4 and IPv6 interfaces, use
4400 DAEMON_OPTIONS(`Name=MTA-v4, Family=inet')
4401 DAEMON_OPTIONS(`Name=MTA-v6, Family=inet6')
4403 A "Message Submission Agent" still uses all of the same rulesets for
4404 processing the message (and therefore still allows message rejection via
4405 the check_* rulesets). In accordance with the RFC, the MSA will ensure
4406 that all domains in envelope addresses are fully qualified if the message
4407 is relayed to another MTA. It will also enforce the normal address syntax
4408 rules and log error messages. Additionally, by using the M=a modifier you
4409 can require authentication before messages are accepted by the MSA.
4410 Notice: Do NOT use the 'a' modifier on a public accessible MTA! Finally,
4411 the M=E modifier shown above disables ETRN as required by RFC 2476.
4413 Mail filters can be defined using the INPUT_MAIL_FILTER() and MAIL_FILTER()
4416 INPUT_MAIL_FILTER(`sample', `S=local:/var/run/f1.sock')
4417 MAIL_FILTER(`myfilter', `S=inet:3333@localhost')
4419 The INPUT_MAIL_FILTER() command causes the filter(s) to be called in the
4420 same order they were specified by also setting confINPUT_MAIL_FILTERS. A
4421 filter can be defined without adding it to the input filter list by using
4422 MAIL_FILTER() instead of INPUT_MAIL_FILTER() in your .mc file.
4423 Alternatively, you can reset the list of filters and their order by setting
4424 confINPUT_MAIL_FILTERS option after all INPUT_MAIL_FILTER() commands in
4428 +----------------------------+
4429 | MESSAGE SUBMISSION PROGRAM |
4430 +----------------------------+
4432 The purpose of the message submission program (MSP) is explained
4433 in sendmail/SECURITY. This section contains a list of caveats and
4434 a few hints how for those who want to tweak the default configuration
4435 for it (which is installed as submit.cf).
4437 Notice: do not add options/features to submit.mc unless you are
4438 absolutely sure you need them. Options you may want to change
4441 - confTRUSTED_USERS, FEATURE(`use_ct_file'), and confCT_FILE for
4442 avoiding X-Authentication warnings.
4443 - confTIME_ZONE to change it from the default `USE_TZ'.
4444 - confDELIVERY_MODE is set to interactive in msp.m4 instead
4445 of the default background mode.
4446 - FEATURE(stickyhost) and LOCAL_RELAY to send unqualified addresses
4447 to the LOCAL_RELAY instead of the default relay.
4448 - confRAND_FILE if you use STARTTLS and sendmail is not compiled with
4449 the flag HASURANDOM.
4451 The MSP performs hostname canonicalization by default. As also
4452 explained in sendmail/SECURITY, mail may end up for various DNS
4453 related reasons in the MSP queue. This problem can be minimized by
4456 FEATURE(`nocanonify', `canonify_hosts')
4457 define(`confDIRECT_SUBMISSION_MODIFIERS', `C')
4459 See the discussion about nocanonify for possible side effects.
4461 Some things are not intended to work with the MSP. These include
4462 features that influence the delivery process (e.g., mailertable,
4463 aliases), or those that are only important for a SMTP server (e.g.,
4464 virtusertable, DaemonPortOptions, multiple queues). Moreover,
4465 relaxing certain restrictions (RestrictQueueRun, permissions on
4466 queue directory) or adding features (e.g., enabling prog/file mailer)
4467 can cause security problems.
4469 Other things don't work well with the MSP and require tweaking or
4470 workarounds. For example, to allow for client authentication it
4471 is not just sufficient to provide a client certificate and the
4472 corresponding key, but it is also necessary to make the key group
4473 (smmsp) readable and tell sendmail not to complain about that, i.e.,
4475 define(`confDONT_BLAME_SENDMAIL', `GroupReadableKeyFile')
4477 If the MSP should actually use AUTH then the necessary data
4478 should be placed in a map as explained in SMTP AUTHENTICATION:
4480 FEATURE(`authinfo', `DATABASE_MAP_TYPE /etc/mail/msp-authinfo')
4482 /etc/mail/msp-authinfo should contain an entry like:
4484 AuthInfo:127.0.0.1 "U:smmsp" "P:secret" "M:DIGEST-MD5"
4486 The file and the map created by makemap should be owned by smmsp,
4487 its group should be smmsp, and it should have mode 640. The database
4488 used by the MTA for AUTH must have a corresponding entry.
4489 Additionally the MTA must trust this authentication data so the AUTH=
4490 part will be relayed on to the next hop. This can be achieved by
4491 adding the following to your sendmail.mc file:
4495 R$* $: $&{auth_authen}
4498 Note: the authentication data can leak to local users who invoke
4499 the MSP with debug options or even with -v. For that reason either
4500 an authentication mechanism that does not show the password in the
4501 AUTH dialogue (e.g., DIGEST-MD5) or a different authentication
4502 method like STARTTLS should be used.
4504 feature/msp.m4 defines almost all settings for the MSP. Most of
4505 those should not be changed at all. Some of the features and options
4506 can be overridden if really necessary. It is a bit tricky to do
4507 this, because it depends on the actual way the option is defined
4508 in feature/msp.m4. If it is directly defined (i.e., define()) then
4509 the modified value must be defined after
4513 If it is conditionally defined (i.e., ifdef()) then the desired
4514 value must be defined before the FEATURE line in the .mc file.
4515 To see how the options are defined read feature/msp.m4.
4518 +--------------------------+
4519 | FORMAT OF FILES AND MAPS |
4520 +--------------------------+
4522 Files that define classes, i.e., F{classname}, consist of lines
4523 each of which contains a single element of the class. For example,
4524 /etc/mail/local-host-names may have the following content:
4529 Maps must be created using makemap(8) , e.g.,
4531 makemap hash MAP < MAP
4533 In general, a text file from which a map is created contains lines
4538 where 'key' and 'value' are also called LHS and RHS, respectively.
4539 By default, the delimiter between LHS and RHS is a non-empty sequence
4540 of white space characters.
4543 +------------------+
4544 | DIRECTORY LAYOUT |
4545 +------------------+
4547 Within this directory are several subdirectories, to wit:
4549 m4 General support routines. These are typically
4550 very important and should not be changed without
4551 very careful consideration.
4553 cf The configuration files themselves. They have
4554 ".mc" suffixes, and must be run through m4 to
4555 become complete. The resulting output should
4556 have a ".cf" suffix.
4558 ostype Definitions describing a particular operating
4559 system type. These should always be referenced
4560 using the OSTYPE macro in the .mc file. Examples
4561 include "bsd4.3", "bsd4.4", "sunos3.5", and
4564 domain Definitions describing a particular domain, referenced
4565 using the DOMAIN macro in the .mc file. These are
4566 site dependent; for example, "CS.Berkeley.EDU.m4"
4567 describes hosts in the CS.Berkeley.EDU subdomain.
4569 mailer Descriptions of mailers. These are referenced using
4570 the MAILER macro in the .mc file.
4572 sh Shell files used when building the .cf file from the
4573 .mc file in the cf subdirectory.
4575 feature These hold special orthogonal features that you might
4576 want to include. They should be referenced using
4579 hack Local hacks. These can be referenced using the HACK
4580 macro. They shouldn't be of more than voyeuristic
4581 interest outside the .Berkeley.EDU domain, but who knows?
4583 siteconfig Site configuration -- e.g., tables of locally connected
4587 +------------------------+
4588 | ADMINISTRATIVE DETAILS |
4589 +------------------------+
4591 The following sections detail usage of certain internal parts of the
4592 sendmail.cf file. Read them carefully if you are trying to modify
4593 the current model. If you find the above descriptions adequate, these
4594 should be {boring, confusing, tedious, ridiculous} (pick one or more).
4596 RULESETS (* means built in to sendmail)
4599 1 * Sender rewriting
4600 2 * Recipient rewriting
4601 3 * Canonicalization
4603 5 * Local address rewrite (after aliasing)
4604 1x mailer rules (sender qualification)
4605 2x mailer rules (recipient qualification)
4606 3x mailer rules (sender header qualification)
4607 4x mailer rules (recipient header qualification)
4608 5x mailer subroutines (general)
4609 6x mailer subroutines (general)
4610 7x mailer subroutines (general)
4612 90 Mailertable host stripping
4613 96 Bottom half of Ruleset 3 (ruleset 6 in old sendmail)
4614 97 Hook for recursive ruleset 0 call (ruleset 7 in old sendmail)
4615 98 Local part of ruleset 0 (ruleset 8 in old sendmail)
4620 0 local, prog local and program mailers
4621 1 [e]smtp, relay SMTP channel
4622 2 uucp-* UNIX-to-UNIX Copy Program
4623 3 netnews Network News delivery
4624 4 fax Sam Leffler's HylaFAX software
4625 5 mail11 DECnet mailer
4633 D The local domain -- usually not needed
4634 E reserved for X.400 Relay
4637 H mail Hub (for mail clusters)
4642 M Masquerade (who you claim to be)
4647 R Relay (for unqualified names)
4650 U my UUCP name (if you have a UUCP connection)
4651 V UUCP Relay (class {V} hosts)
4652 W UUCP Relay (class {W} hosts)
4653 X UUCP Relay (class {X} hosts)
4654 Y UUCP Relay (all other hosts)
4661 B domains that are candidates for bestmx lookup
4664 E addresses that should not seem to come from $M
4665 F hosts this system forward for
4666 G domains that should be looked up in genericstable
4671 L addresses that should not be forwarded to $R
4672 M domains that should be mapped to $M
4673 N host/domains that should not be mapped to $M
4674 O operators that indicate network operations (cannot be in local names)
4675 P top level pseudo-domains: BITNET, DECNET, FAX, UUCP, etc.
4677 R domains this system is willing to relay (pass anti-spam filters)
4680 U locally connected UUCP hosts
4681 V UUCP hosts connected to relay $V
4682 W UUCP hosts connected to relay $W
4683 X UUCP hosts connected to relay $X
4684 Y locally connected smart UUCP hosts
4685 Z locally connected domain-ized UUCP hosts
4686 . the class containing only a dot
4687 [ the class containing only a left bracket
4692 1 Local host detection and resolution
4693 2 Local Ruleset 3 additions
4694 3 Local Ruleset 0 additions
4695 4 UUCP Ruleset 0 additions
4696 5 locally interpreted names (overrides $R)
4697 6 local configuration (at top of file)
4698 7 mailer definitions
4699 8 DNS based blacklists
4700 9 special local rulesets (1 and 2)
4702 $Revision: 8.722 $, Last updated $Date: 2007/04/03 21:26:58 $