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 Proofpoint, 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 *******************************************************************
162 Some rulesets, features, and options are only useful if the sendmail
163 binary has been compiled with the appropriate options, e.g., the
164 ruleset tls_server is only invoked if sendmail has been compiled
165 with STARTTLS. This is usually obvious from the context and hence
166 not further specified here.
167 There are also so called "For Future Releases" (FFR) compile time
168 options which might be included in a subsequent version or might
169 simply be removed as they turned out not to be really useful.
170 These are generally not documented but if they are, then the required
171 compile time options are listed in doc/op/op.* for rulesets and
172 macros, and for mc/cf specific options they are usually listed here.
173 In addition to compile time options for the sendmail binary, there
174 can also be FFRs for mc/cf which in general can be enabled when the
175 configuration file is generated by defining them at the top of your
178 define(`_FFR_NAME_HERE', 1)
181 +----------------------------+
182 | A BRIEF INTRODUCTION TO M4 |
183 +----------------------------+
185 Sendmail uses the M4 macro processor to ``compile'' the configuration
186 files. The most important thing to know is that M4 is stream-based,
187 that is, it doesn't understand about lines. For this reason, in some
188 places you may see the word ``dnl'', which stands for ``delete
189 through newline''; essentially, it deletes all characters starting
190 at the ``dnl'' up to and including the next newline character. In
191 most cases sendmail uses this only to avoid lots of unnecessary
192 blank lines in the output.
194 Other important directives are define(A, B) which defines the macro
195 ``A'' to have value ``B''. Macros are expanded as they are read, so
196 one normally quotes both values to prevent expansion. For example,
198 define(`SMART_HOST', `smart.foo.com')
200 One word of warning: M4 macros are expanded even in lines that appear
201 to be comments. For example, if you have
203 # See FEATURE(`foo') above
205 it will not do what you expect, because the FEATURE(`foo') will be
206 expanded. This also applies to
208 # And then define the $X macro to be the return address
210 because ``define'' is an M4 keyword. If you want to use them, surround
211 them with directed quotes, `like this'.
213 Since m4 uses single quotes (opening "`" and closing "'") to quote
214 arguments, those quotes can't be used in arguments. For example,
215 it is not possible to define a rejection message containing a single
216 quote. Usually there are simple workarounds by changing those
217 messages; in the worst case it might be ok to change the value
218 directly in the generated .cf file, which however is not advised.
224 This package requires a post-V7 version of m4; if you are running the
225 4.2bsd, SysV.2, or 7th Edition version. SunOS's /usr/5bin/m4 or
226 BSD-Net/2's m4 both work. GNU m4 version 1.1 or later also works.
227 Unfortunately, the M4 on BSDI 1.0 doesn't work -- you'll have to use a
228 Net/2 or GNU version. GNU m4 is available from
229 ftp://ftp.gnu.org/pub/gnu/m4/m4-1.4.tar.gz (check for the latest version).
230 EXCEPTIONS: DEC's m4 on Digital UNIX 4.x is broken (3.x is fine). Use GNU
238 sendmail 8.9 has introduced a new configuration directory for sendmail
239 related files, /etc/mail. The new files available for sendmail 8.9 --
240 the class {R} /etc/mail/relay-domains and the access database
241 /etc/mail/access -- take advantage of this new directory. Beginning with
242 8.10, all files will use this directory by default (some options may be
243 set by OSTYPE() files). This new directory should help to restore
244 uniformity to sendmail's file locations.
246 Below is a table of some of the common changes:
248 Old filename New filename
249 ------------ ------------
250 /etc/bitdomain /etc/mail/bitdomain
251 /etc/domaintable /etc/mail/domaintable
252 /etc/genericstable /etc/mail/genericstable
253 /etc/uudomain /etc/mail/uudomain
254 /etc/virtusertable /etc/mail/virtusertable
255 /etc/userdb /etc/mail/userdb
257 /etc/aliases /etc/mail/aliases
258 /etc/sendmail/aliases /etc/mail/aliases
259 /etc/ucbmail/aliases /etc/mail/aliases
260 /usr/adm/sendmail/aliases /etc/mail/aliases
261 /usr/lib/aliases /etc/mail/aliases
262 /usr/lib/mail/aliases /etc/mail/aliases
263 /usr/ucblib/aliases /etc/mail/aliases
265 /etc/sendmail.cw /etc/mail/local-host-names
266 /etc/mail/sendmail.cw /etc/mail/local-host-names
267 /etc/sendmail/sendmail.cw /etc/mail/local-host-names
269 /etc/sendmail.ct /etc/mail/trusted-users
271 /etc/sendmail.oE /etc/mail/error-header
273 /etc/sendmail.hf /etc/mail/helpfile
274 /etc/mail/sendmail.hf /etc/mail/helpfile
275 /usr/ucblib/sendmail.hf /etc/mail/helpfile
276 /etc/ucbmail/sendmail.hf /etc/mail/helpfile
277 /usr/lib/sendmail.hf /etc/mail/helpfile
278 /usr/share/lib/sendmail.hf /etc/mail/helpfile
279 /usr/share/misc/sendmail.hf /etc/mail/helpfile
280 /share/misc/sendmail.hf /etc/mail/helpfile
282 /etc/service.switch /etc/mail/service.switch
284 /etc/sendmail.st /etc/mail/statistics
285 /etc/mail/sendmail.st /etc/mail/statistics
286 /etc/mailer/sendmail.st /etc/mail/statistics
287 /etc/sendmail/sendmail.st /etc/mail/statistics
288 /usr/lib/sendmail.st /etc/mail/statistics
289 /usr/ucblib/sendmail.st /etc/mail/statistics
291 Note that all of these paths actually use a new m4 macro MAIL_SETTINGS_DIR
292 to create the pathnames. The default value of this variable is
293 `/etc/mail/'. If you set this macro to a different value, you MUST include
296 Notice: all filenames used in a .mc (or .cf) file should be absolute
297 (starting at the root, i.e., with '/'). Relative filenames most
298 likely cause surprises during operations (unless otherwise noted).
305 You MUST define an operating system environment, or the configuration
306 file build will puke. There are several environments available; look
307 at the "ostype" directory for the current list. This macro changes
308 things like the location of the alias file and queue directory. Some
309 of these files are identical to one another.
311 It is IMPERATIVE that the OSTYPE occur before any MAILER definitions.
312 In general, the OSTYPE macro should go immediately after any version
313 information, and MAILER definitions should always go last.
315 Operating system definitions are usually easy to write. They may define
316 the following variables (everything defaults, so an ostype file may be
317 empty). Unfortunately, the list of configuration-supported systems is
318 not as broad as the list of source-supported systems, since many of
319 the source contributors do not include corresponding ostype files.
321 ALIAS_FILE [/etc/mail/aliases] The location of the text version
322 of the alias file(s). It can be a comma-separated
323 list of names (but be sure you quote values with
324 commas in them -- for example, use
325 define(`ALIAS_FILE', `a,b')
326 to get "a" and "b" both listed as alias files;
327 otherwise the define() primitive only sees "a").
328 HELP_FILE [/etc/mail/helpfile] The name of the file
329 containing information printed in response to
330 the SMTP HELP command.
331 QUEUE_DIR [/var/spool/mqueue] The directory containing
332 queue files. To use multiple queues, supply
333 a value ending with an asterisk. For
334 example, /var/spool/mqueue/qd* will use all of the
335 directories or symbolic links to directories
336 beginning with 'qd' in /var/spool/mqueue as queue
337 directories. The names 'qf', 'df', and 'xf' are
338 reserved as specific subdirectories for the
339 corresponding queue file types as explained in
340 doc/op/op.me. See also QUEUE GROUP DEFINITIONS.
341 MSP_QUEUE_DIR [/var/spool/clientmqueue] The directory containing
342 queue files for the MSP (Mail Submission Program,
343 see sendmail/SECURITY).
344 STATUS_FILE [/etc/mail/statistics] The file containing status
346 LOCAL_MAILER_PATH [/bin/mail] The program used to deliver local mail.
347 LOCAL_MAILER_FLAGS [Prmn9] The flags used by the local mailer. The
348 flags lsDFMAw5:/|@q are always included.
349 LOCAL_MAILER_ARGS [mail -d $u] The arguments passed to deliver local
351 LOCAL_MAILER_MAX [undefined] If defined, the maximum size of local
352 mail that you are willing to accept.
353 LOCAL_MAILER_MAXMSGS [undefined] If defined, the maximum number of
354 messages to deliver in a single connection. Only
355 useful for LMTP local mailers.
356 LOCAL_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
357 that ARRIVE from an address that resolves to the
358 local mailer and which are converted to MIME will be
359 labeled with this character set.
360 LOCAL_MAILER_EOL [undefined] If defined, the string to use as the
361 end of line for the local mailer.
362 LOCAL_MAILER_DSN_DIAGNOSTIC_CODE
363 [X-Unix] The DSN Diagnostic-Code value for the
364 local mailer. This should be changed with care.
365 LOCAL_SHELL_PATH [/bin/sh] The shell used to deliver piped email.
366 LOCAL_SHELL_FLAGS [eu9] The flags used by the shell mailer. The
367 flags lsDFM are always included.
368 LOCAL_SHELL_ARGS [sh -c $u] The arguments passed to deliver "prog"
370 LOCAL_SHELL_DIR [$z:/] The directory search path in which the
372 LOCAL_MAILER_QGRP [undefined] The queue group for the local mailer.
373 USENET_MAILER_PATH [/usr/lib/news/inews] The name of the program
375 USENET_MAILER_FLAGS [rsDFMmn] The mailer flags for the usenet mailer.
376 USENET_MAILER_ARGS [-m -h -n] The command line arguments for the
377 usenet mailer. NOTE: Some versions of inews
378 (such as those shipped with newer versions of INN)
379 use different flags. Double check the defaults
380 against the inews man page.
381 USENET_MAILER_MAX [undefined] The maximum size of messages that will
382 be accepted by the usenet mailer.
383 USENET_MAILER_QGRP [undefined] The queue group for the usenet mailer.
384 SMTP_MAILER_FLAGS [undefined] Flags added to SMTP mailer. Default
385 flags are `mDFMuX' for all SMTP-based mailers; the
386 "esmtp" mailer adds `a'; "smtp8" adds `8'; and
388 RELAY_MAILER_FLAGS [undefined] Flags added to the relay mailer. Default
389 flags are `mDFMuX' for all SMTP-based mailers; the
390 relay mailer adds `a8'. If this is not defined,
391 then SMTP_MAILER_FLAGS is used.
392 SMTP_MAILER_MAX [undefined] The maximum size of messages that will
393 be transported using the smtp, smtp8, esmtp, or dsmtp
395 SMTP_MAILER_MAXMSGS [undefined] If defined, the maximum number of
396 messages to deliver in a single connection for the
397 smtp, smtp8, esmtp, or dsmtp mailers.
398 SMTP_MAILER_MAXRCPTS [undefined] If defined, the maximum number of
399 recipients to deliver in a single envelope for the
400 smtp, smtp8, esmtp, or dsmtp mailers.
401 SMTP_MAILER_ARGS [TCP $h] The arguments passed to the smtp mailer.
402 About the only reason you would want to change this
403 would be to change the default port.
404 ESMTP_MAILER_ARGS [TCP $h] The arguments passed to the esmtp mailer.
405 SMTP8_MAILER_ARGS [TCP $h] The arguments passed to the smtp8 mailer.
406 DSMTP_MAILER_ARGS [TCP $h] The arguments passed to the dsmtp mailer.
407 RELAY_MAILER_ARGS [TCP $h] The arguments passed to the relay mailer.
408 SMTP_MAILER_QGRP [undefined] The queue group for the smtp mailer.
409 ESMTP_MAILER_QGRP [undefined] The queue group for the esmtp mailer.
410 SMTP8_MAILER_QGRP [undefined] The queue group for the smtp8 mailer.
411 DSMTP_MAILER_QGRP [undefined] The queue group for the dsmtp mailer.
412 RELAY_MAILER_QGRP [undefined] The queue group for the relay mailer.
413 RELAY_MAILER_MAXMSGS [undefined] If defined, the maximum number of
414 messages to deliver in a single connection for the
416 SMTP_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
417 that ARRIVE from an address that resolves to one of
418 the SMTP mailers and which are converted to MIME will
419 be labeled with this character set.
420 RELAY_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
421 that ARRIVE from an address that resolves to the
422 relay mailers and which are converted to MIME will
423 be labeled with this character set.
424 SMTP_MAILER_LL [990] The maximum line length for SMTP mailers
425 (except the relay mailer).
426 RELAY_MAILER_LL [2040] The maximum line length for the relay mailer.
427 UUCP_MAILER_PATH [/usr/bin/uux] The program used to send UUCP mail.
428 UUCP_MAILER_FLAGS [undefined] Flags added to UUCP mailer. Default
429 flags are `DFMhuU' (and `m' for uucp-new mailer,
430 minus `U' for uucp-dom mailer).
431 UUCP_MAILER_ARGS [uux - -r -z -a$g -gC $h!rmail ($u)] The arguments
432 passed to the UUCP mailer.
433 UUCP_MAILER_MAX [100000] The maximum size message accepted for
434 transmission by the UUCP mailers.
435 UUCP_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
436 that ARRIVE from an address that resolves to one of
437 the UUCP mailers and which are converted to MIME will
438 be labeled with this character set.
439 UUCP_MAILER_QGRP [undefined] The queue group for the UUCP mailers.
440 FAX_MAILER_PATH [/usr/local/lib/fax/mailfax] The program used to
442 FAX_MAILER_ARGS [mailfax $u $h $f] The arguments passed to the FAX
444 FAX_MAILER_MAX [100000] The maximum size message accepted for
446 POP_MAILER_PATH [/usr/lib/mh/spop] The pathname of the POP mailer.
447 POP_MAILER_FLAGS [Penu] Flags added to POP mailer. Flags lsDFMq
449 POP_MAILER_ARGS [pop $u] The arguments passed to the POP mailer.
450 POP_MAILER_QGRP [undefined] The queue group for the pop mailer.
451 PROCMAIL_MAILER_PATH [/usr/local/bin/procmail] The path to the procmail
452 program. This is also used by
453 FEATURE(`local_procmail').
454 PROCMAIL_MAILER_FLAGS [SPhnu9] Flags added to Procmail mailer. Flags
455 DFM are always set. This is NOT used by
456 FEATURE(`local_procmail'); tweak LOCAL_MAILER_FLAGS
458 PROCMAIL_MAILER_ARGS [procmail -Y -m $h $f $u] The arguments passed to
459 the Procmail mailer. This is NOT used by
460 FEATURE(`local_procmail'); tweak LOCAL_MAILER_ARGS
462 PROCMAIL_MAILER_MAX [undefined] If set, the maximum size message that
463 will be accepted by the procmail mailer.
464 PROCMAIL_MAILER_QGRP [undefined] The queue group for the procmail mailer.
465 MAIL11_MAILER_PATH [/usr/etc/mail11] The path to the mail11 mailer.
466 MAIL11_MAILER_FLAGS [nsFx] Flags for the mail11 mailer.
467 MAIL11_MAILER_ARGS [mail11 $g $x $h $u] Arguments passed to the mail11
469 MAIL11_MAILER_QGRP [undefined] The queue group for the mail11 mailer.
470 PH_MAILER_PATH [/usr/local/etc/phquery] The path to the phquery
472 PH_MAILER_FLAGS [ehmu] Flags for the phquery mailer. Flags nrDFM
474 PH_MAILER_ARGS [phquery -- $u] -- arguments to the phquery mailer.
475 PH_MAILER_QGRP [undefined] The queue group for the ph mailer.
476 CYRUS_MAILER_FLAGS [Ah5@/:|] The flags used by the cyrus mailer. The
477 flags lsDFMnPq are always included.
478 CYRUS_MAILER_PATH [/usr/cyrus/bin/deliver] The program used to deliver
480 CYRUS_MAILER_ARGS [deliver -e -m $h -- $u] The arguments passed
481 to deliver cyrus mail.
482 CYRUS_MAILER_MAX [undefined] If set, the maximum size message that
483 will be accepted by the cyrus mailer.
484 CYRUS_MAILER_USER [cyrus:mail] The user and group to become when
485 running the cyrus mailer.
486 CYRUS_MAILER_QGRP [undefined] The queue group for the cyrus mailer.
487 CYRUS_BB_MAILER_FLAGS [u] The flags used by the cyrusbb mailer.
488 The flags lsDFMnP are always included.
489 CYRUS_BB_MAILER_ARGS [deliver -e -m $u] The arguments passed
490 to deliver cyrusbb mail.
491 CYRUSV2_MAILER_FLAGS [A@/:|m] The flags used by the cyrusv2 mailer. The
492 flags lsDFMnqXz are always included.
493 CYRUSV2_MAILER_MAXMSGS [undefined] If defined, the maximum number of
494 messages to deliver in a single connection for the
496 CYRUSV2_MAILER_MAXRCPTS [undefined] If defined, the maximum number of
497 recipients to deliver in a single connection for the
499 CYRUSV2_MAILER_ARGS [FILE /var/imap/socket/lmtp] The arguments passed
500 to the cyrusv2 mailer. This can be used to
501 change the name of the Unix domain socket, or
502 to switch to delivery via TCP (e.g., `TCP $h lmtp')
503 CYRUSV2_MAILER_QGRP [undefined] The queue group for the cyrusv2 mailer.
504 CYRUSV2_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
505 that ARRIVE from an address that resolves to one the
506 Cyrus mailer and which are converted to MIME will
507 be labeled with this character set.
508 confEBINDIR [/usr/libexec] The directory for executables.
509 Currently used for FEATURE(`local_lmtp') and
511 QPAGE_MAILER_FLAGS [mDFMs] The flags used by the qpage mailer.
512 QPAGE_MAILER_PATH [/usr/local/bin/qpage] The program used to deliver
514 QPAGE_MAILER_ARGS [qpage -l0 -m -P$u] The arguments passed
515 to deliver qpage mail.
516 QPAGE_MAILER_MAX [4096] If set, the maximum size message that
517 will be accepted by the qpage mailer.
518 QPAGE_MAILER_QGRP [undefined] The queue group for the qpage mailer.
519 LOCAL_PROG_QGRP [undefined] The queue group for the prog mailer.
521 Note: to tweak Name_MAILER_FLAGS use the macro MODIFY_MAILER_FLAGS:
522 MODIFY_MAILER_FLAGS(`Name', `change') where Name is the first part
523 of the macro Name_MAILER_FLAGS (note: that means Name is entirely in
524 upper case) and change can be: flags that should be used directly
525 (thus overriding the default value), or if it starts with `+' (`-')
526 then those flags are added to (removed from) the default value.
529 MODIFY_MAILER_FLAGS(`LOCAL', `+e')
531 will add the flag `e' to LOCAL_MAILER_FLAGS. Notice: there are
532 several smtp mailers all of which are manipulated individually.
533 See the section MAILERS for the available mailer names.
534 WARNING: The FEATUREs local_lmtp and local_procmail set LOCAL_MAILER_FLAGS
535 unconditionally, i.e., without respecting any definitions in an
543 You will probably want to collect domain-dependent defines into one
544 file, referenced by the DOMAIN macro. For example, the Berkeley
545 domain file includes definitions for several internal distinguished
548 UUCP_RELAY The host that will accept UUCP-addressed email.
549 If not defined, all UUCP sites must be directly
551 BITNET_RELAY The host that will accept BITNET-addressed email.
552 If not defined, the .BITNET pseudo-domain won't work.
553 DECNET_RELAY The host that will accept DECNET-addressed email.
554 If not defined, the .DECNET pseudo-domain and addresses
555 of the form node::user will not work.
556 FAX_RELAY The host that will accept mail to the .FAX pseudo-domain.
557 The "fax" mailer overrides this value.
558 LOCAL_RELAY The site that will handle unqualified names -- that
559 is, names without an @domain extension.
560 Normally MAIL_HUB is preferred for this function.
561 LOCAL_RELAY is mostly useful in conjunction with
562 FEATURE(`stickyhost') -- see the discussion of
563 stickyhost below. If not set, they are assumed to
564 belong on this machine. This allows you to have a
565 central site to store a company- or department-wide
566 alias database. This only works at small sites,
567 and only with some user agents.
568 LUSER_RELAY The site that will handle lusers -- that is, apparently
569 local names that aren't local accounts or aliases. To
570 specify a local user instead of a site, set this to
573 Any of these can be either ``mailer:hostname'' (in which case the
574 mailer is the internal mailer name, such as ``uucp-new'' and the hostname
575 is the name of the host as appropriate for that mailer) or just a
576 ``hostname'', in which case a default mailer type (usually ``relay'',
577 a variant on SMTP) is used. WARNING: if you have a wildcard MX
578 record matching your domain, you probably want to define these to
579 have a trailing dot so that you won't get the mail diverted back
582 The domain file can also be used to define a domain name, if needed
583 (using "DD<domain>") and set certain site-wide features. If all hosts
584 at your site masquerade behind one email name, you could also use
587 You do not have to define a domain -- in particular, if you are a
588 single machine sitting off somewhere, it is probably more work than
589 it's worth. This is just a mechanism for combining "domain dependent
590 knowledge" into one place.
597 There are fewer mailers supported in this version than the previous
598 version, owing mostly to a simpler world. As a general rule, put the
599 MAILER definitions last in your .mc file.
601 local The local and prog mailers. You will almost always
602 need these; the only exception is if you relay ALL
603 your mail to another site. This mailer is included
606 smtp The Simple Mail Transport Protocol mailer. This does
607 not hide hosts behind a gateway or another other
608 such hack; it assumes a world where everyone is
609 running the name server. This file actually defines
610 five mailers: "smtp" for regular (old-style) SMTP to
611 other servers, "esmtp" for extended SMTP to other
612 servers, "smtp8" to do SMTP to other servers without
613 converting 8-bit data to MIME (essentially, this is
614 your statement that you know the other end is 8-bit
615 clean even if it doesn't say so), "dsmtp" to do on
616 demand delivery, and "relay" for transmission to the
617 RELAY_HOST, LUSER_RELAY, or MAIL_HUB.
619 uucp The UNIX-to-UNIX Copy Program mailer. Actually, this
620 defines two mailers, "uucp-old" (a.k.a. "uucp") and
621 "uucp-new" (a.k.a. "suucp"). The latter is for when you
622 know that the UUCP mailer at the other end can handle
623 multiple recipients in one transfer. If the smtp mailer
624 is included in your configuration, two other mailers
625 ("uucp-dom" and "uucp-uudom") are also defined [warning: you
626 MUST specify MAILER(`smtp') before MAILER(`uucp')]. When you
627 include the uucp mailer, sendmail looks for all names in
628 class {U} and sends them to the uucp-old mailer; all
629 names in class {Y} are sent to uucp-new; and all
630 names in class {Z} are sent to uucp-uudom. Note that
631 this is a function of what version of rmail runs on
632 the receiving end, and hence may be out of your control.
633 See the section below describing UUCP mailers in more
636 usenet Usenet (network news) delivery. If this is specified,
637 an extra rule is added to ruleset 0 that forwards all
638 local email for users named ``group.usenet'' to the
639 ``inews'' program. Note that this works for all groups,
640 and may be considered a security problem.
642 fax Facsimile transmission. This is experimental and based
643 on Sam Leffler's HylaFAX software. For more information,
644 see http://www.hylafax.org/.
646 pop Post Office Protocol.
648 procmail An interface to procmail (does not come with sendmail).
649 This is designed to be used in mailertables. For example,
650 a common question is "how do I forward all mail for a given
651 domain to a single person?". If you have this mailer
652 defined, you could set up a mailertable reading:
654 host.com procmail:/etc/procmailrcs/host.com
656 with the file /etc/procmailrcs/host.com reading:
658 :0 # forward mail for host.com
659 ! -oi -f $1 person@other.host
661 This would arrange for (anything)@host.com to be sent
662 to person@other.host. In a procmail script, $1 is the
663 name of the sender and $2 is the name of the recipient.
664 If you use this with FEATURE(`local_procmail'), the FEATURE
665 should be listed first.
667 Of course there are other ways to solve this particular
668 problem, e.g., a catch-all entry in a virtusertable.
670 mail11 The DECnet mail11 mailer, useful only if you have the mail11
671 program from gatekeeper.dec.com:/pub/DEC/gwtools (and
672 DECnet, of course). This is for Phase IV DECnet support;
673 if you have Phase V at your site you may have additional
676 phquery The phquery program. This is somewhat counterintuitively
677 referenced as the "ph" mailer internally. It can be used
678 to do CCSO name server lookups. The phquery program, which
679 this mailer uses, is distributed with the ph client.
681 cyrus The cyrus and cyrusbb mailers. The cyrus mailer delivers to
682 a local cyrus user. this mailer can make use of the
683 "user+detail@local.host" syntax (see
684 FEATURE(`preserve_local_plus_detail')); it will deliver the
685 mail to the user's "detail" mailbox if the mailbox's ACL
686 permits. The cyrusbb mailer delivers to a system-wide
687 cyrus mailbox if the mailbox's ACL permits. The cyrus
688 mailer must be defined after the local mailer.
690 cyrusv2 The mailer for Cyrus v2.x. The cyrusv2 mailer delivers to
691 local cyrus users via LMTP. This mailer can make use of the
692 "user+detail@local.host" syntax (see
693 FEATURE(`preserve_local_plus_detail')); it will deliver the
694 mail to the user's "detail" mailbox if the mailbox's ACL
695 permits. The cyrusv2 mailer must be defined after the
698 qpage A mailer for QuickPage, a pager interface. See
699 http://www.qpage.org/ for further information.
701 The local mailer accepts addresses of the form "user+detail", where
702 the "+detail" is not used for mailbox matching but is available
703 to certain local mail programs (in particular, see
704 FEATURE(`local_procmail')). For example, "eric", "eric+sendmail", and
705 "eric+sww" all indicate the same user, but additional arguments <null>,
706 "sendmail", and "sww" may be provided for use in sorting mail.
713 Special features can be requested using the "FEATURE" macro. For
714 example, the .mc line:
716 FEATURE(`use_cw_file')
718 tells sendmail that you want to have it read an /etc/mail/local-host-names
719 file to get values for class {w}. A FEATURE may contain up to 9
720 optional parameters -- for example:
722 FEATURE(`mailertable', `dbm /usr/lib/mailertable')
724 The default database map type for the table features can be set with
726 define(`DATABASE_MAP_TYPE', `dbm')
728 which would set it to use ndbm databases. The default is the Berkeley DB
729 hash database format. Note that you must still declare a database map type
730 if you specify an argument to a FEATURE. DATABASE_MAP_TYPE is only used
731 if no argument is given for the FEATURE. It must be specified before any
732 feature that uses a map.
734 Also, features which can take a map definition as an argument can also take
735 the special keyword `LDAP'. If that keyword is used, the map will use the
736 LDAP definition described in the ``USING LDAP FOR ALIASES, MAPS, AND
737 CLASSES'' section below.
739 Available features are:
741 use_cw_file Read the file /etc/mail/local-host-names file to get
742 alternate names for this host. This might be used if you
743 were on a host that MXed for a dynamic set of other hosts.
744 If the set is static, just including the line "Cw<name1>
745 <name2> ..." (where the names are fully qualified domain
746 names) is probably superior. The actual filename can be
747 overridden by redefining confCW_FILE.
749 use_ct_file Read the file /etc/mail/trusted-users file to get the
750 names of users that will be ``trusted'', that is, able to
751 set their envelope from address using -f without generating
752 a warning message. The actual filename can be overridden
753 by redefining confCT_FILE.
755 redirect Reject all mail addressed to "address.REDIRECT" with
756 a ``551 User has moved; please try <address>'' message.
757 If this is set, you can alias people who have left
758 to their new address with ".REDIRECT" appended.
760 nouucp Don't route UUCP addresses. This feature takes one
762 `reject': reject addresses which have "!" in the local
763 part unless it originates from a system
764 that is allowed to relay.
765 `nospecial': don't do anything special with "!".
766 Warnings: 1. See the notice in the anti-spam section.
767 2. don't remove "!" from OperatorChars if `reject' is
770 nopercenthack Don't treat % as routing character. This feature takes one
772 `reject': reject addresses which have % in the local
773 part unless it originates from a system
774 that is allowed to relay.
775 `nospecial': don't do anything special with %.
776 Warnings: 1. See the notice in the anti-spam section.
777 2. Don't remove % from OperatorChars if `reject' is
780 nocanonify Don't pass addresses to $[ ... $] for canonification
781 by default, i.e., host/domain names are considered canonical,
782 except for unqualified names, which must not be used in this
783 mode (violation of the standard). It can be changed by
784 setting the DaemonPortOptions modifiers (M=). That is,
785 FEATURE(`nocanonify') will be overridden by setting the
786 'c' flag. Conversely, if FEATURE(`nocanonify') is not used,
787 it can be emulated by setting the 'C' flag
788 (DaemonPortOptions=Modifiers=C). This would generally only
789 be used by sites that only act as mail gateways or which have
790 user agents that do full canonification themselves. You may
792 "define(`confBIND_OPTS', `-DNSRCH -DEFNAMES')" to turn off
793 the usual resolver options that do a similar thing.
795 An exception list for FEATURE(`nocanonify') can be
796 specified with CANONIFY_DOMAIN or CANONIFY_DOMAIN_FILE,
797 i.e., a list of domains which are nevertheless passed to
798 $[ ... $] for canonification. This is useful to turn on
799 canonification for local domains, e.g., use
800 CANONIFY_DOMAIN(`my.domain my') to canonify addresses
801 which end in "my.domain" or "my".
802 Another way to require canonification in the local
803 domain is CANONIFY_DOMAIN(`$=m').
805 A trailing dot is added to addresses with more than
806 one component in it such that other features which
807 expect a trailing dot (e.g., virtusertable) will
810 If `canonify_hosts' is specified as parameter, i.e.,
811 FEATURE(`nocanonify', `canonify_hosts'), then
812 addresses which have only a hostname, e.g.,
813 <user@host>, will be canonified (and hopefully fully
816 stickyhost This feature is sometimes used with LOCAL_RELAY,
817 although it can be used for a different effect with
820 When used without MAIL_HUB, email sent to
821 "user@local.host" are marked as "sticky" -- that
822 is, the local addresses aren't matched against UDB,
823 don't go through ruleset 5, and are not forwarded to
824 the LOCAL_RELAY (if defined).
826 With MAIL_HUB, mail addressed to "user@local.host"
827 is forwarded to the mail hub, with the envelope
828 address still remaining "user@local.host".
829 Without stickyhost, the envelope would be changed
830 to "user@mail_hub", in order to protect against
833 mailertable Include a "mailer table" which can be used to override
834 routing for particular domains (which are not in class {w},
835 i.e. local host names). The argument of the FEATURE may be
836 the key definition. If none is specified, the definition
839 hash /etc/mail/mailertable
841 Keys in this database are fully qualified domain names
842 or partial domains preceded by a dot -- for example,
843 "vangogh.CS.Berkeley.EDU" or ".CS.Berkeley.EDU". As a
844 special case of the latter, "." matches any domain not
845 covered by other keys. Values must be of the form:
847 where "mailer" is the internal mailer name, and "domain"
848 is where to send the message. These maps are not
849 reflected into the message header. As a special case,
852 will forward to the indicated user using the local mailer,
854 will forward to the original user in the e-mail address
855 using the local mailer, and
857 error:D.S.N:code message
858 will give an error message with the indicated SMTP reply
859 code and message, where D.S.N is an RFC 1893 compliant
862 domaintable Include a "domain table" which can be used to provide
863 domain name mapping. Use of this should really be
864 limited to your own domains. It may be useful if you
865 change names (e.g., your company changes names from
866 oldname.com to newname.com). The argument of the
867 FEATURE may be the key definition. If none is specified,
868 the definition used is:
870 hash /etc/mail/domaintable
872 The key in this table is the domain name; the value is
873 the new (fully qualified) domain. Anything in the
874 domaintable is reflected into headers; that is, this
875 is done in ruleset 3.
877 bitdomain Look up bitnet hosts in a table to try to turn them into
878 internet addresses. The table can be built using the
879 bitdomain program contributed by John Gardiner Myers.
880 The argument of the FEATURE may be the key definition; if
881 none is specified, the definition used is:
883 hash /etc/mail/bitdomain
885 Keys are the bitnet hostname; values are the corresponding
888 uucpdomain Similar feature for UUCP hosts. The default map definition
891 hash /etc/mail/uudomain
893 At the moment there is no automagic tool to build this
897 Include the local host domain even on locally delivered
898 mail. Normally it is not added on unqualified names.
899 However, if you use a shared message store but do not use
900 the same user name space everywhere, you may need the host
901 name on local names. An optional argument specifies
902 another domain to be added than the local.
904 allmasquerade If masquerading is enabled (using MASQUERADE_AS), this
905 feature will cause recipient addresses to also masquerade
906 as being from the masquerade host. Normally they get
907 the local hostname. Although this may be right for
908 ordinary users, it can break local aliases. For example,
909 if you send to "localalias", the originating sendmail will
910 find that alias and send to all members, but send the
911 message with "To: localalias@masqueradehost". Since that
912 alias likely does not exist, replies will fail. Use this
913 feature ONLY if you can guarantee that the ENTIRE
914 namespace on your masquerade host supersets all the
918 Normally, any hosts listed in class {w} are masqueraded. If
919 this feature is given, only the hosts listed in class {M} (see
920 below: MASQUERADE_DOMAIN) are masqueraded. This is useful
921 if you have several domains with disjoint namespaces hosted
924 masquerade_entire_domain
925 If masquerading is enabled (using MASQUERADE_AS) and
926 MASQUERADE_DOMAIN (see below) is set, this feature will
927 cause addresses to be rewritten such that the masquerading
928 domains are actually entire domains to be hidden. All
929 hosts within the masquerading domains will be rewritten
930 to the masquerade name (used in MASQUERADE_AS). For example,
933 MASQUERADE_AS(`masq.com')
934 MASQUERADE_DOMAIN(`foo.org')
935 MASQUERADE_DOMAIN(`bar.com')
937 then *foo.org and *bar.com are converted to masq.com. Without
938 this feature, only foo.org and bar.com are masqueraded.
940 NOTE: only domains within your jurisdiction and
941 current hierarchy should be masqueraded using this.
944 This feature prevents the local mailer from masquerading even
945 if MASQUERADE_AS is used. MASQUERADE_AS will only have effect
946 on addresses of mail going outside the local domain.
949 If masquerading is enabled (using MASQUERADE_AS) or the
950 genericstable is in use, this feature will cause envelope
951 addresses to also masquerade as being from the masquerade
952 host. Normally only the header addresses are masqueraded.
954 genericstable This feature will cause unqualified addresses (i.e., without
955 a domain) and addresses with a domain listed in class {G}
956 to be looked up in a map and turned into another ("generic")
957 form, which can change both the domain name and the user name.
958 Notice: if you use an MSP (as it is default starting with
959 8.12), the MTA will only receive qualified addresses from the
960 MSP (as required by the RFCs). Hence you need to add your
961 domain to class {G}. This feature is similar to the userdb
962 functionality. The same types of addresses as for
963 masquerading are looked up, i.e., only header sender
964 addresses unless the allmasquerade and/or masquerade_envelope
965 features are given. Qualified addresses must have the domain
966 part in class {G}; entries can be added to this class by the
967 macros GENERICS_DOMAIN or GENERICS_DOMAIN_FILE (analogously
968 to MASQUERADE_DOMAIN and MASQUERADE_DOMAIN_FILE, see below).
970 The argument of FEATURE(`genericstable') may be the map
971 definition; the default map definition is:
973 hash /etc/mail/genericstable
975 The key for this table is either the full address, the domain
976 (with a leading @; the localpart is passed as first argument)
977 or the unqualified username (tried in the order mentioned);
978 the value is the new user address. If the new user address
979 does not include a domain, it will be qualified in the standard
980 manner, i.e., using $j or the masquerade name. Note that the
981 address being looked up must be fully qualified. For local
982 mail, it is necessary to use FEATURE(`always_add_domain')
983 for the addresses to be qualified.
984 The "+detail" of an address is passed as %1, so entries like
986 old+*@foo.org new+%1@example.com
987 gen+*@foo.org %1@example.com
989 and other forms are possible.
991 generics_entire_domain
992 If the genericstable is enabled and GENERICS_DOMAIN or
993 GENERICS_DOMAIN_FILE is used, this feature will cause
994 addresses to be searched in the map if their domain
995 parts are subdomains of elements in class {G}.
997 virtusertable A domain-specific form of aliasing, allowing multiple
998 virtual domains to be hosted on one machine. For example,
999 if the virtuser table contains:
1001 info@foo.com foo-info
1002 info@bar.com bar-info
1003 joe@bar.com error:nouser 550 No such user here
1004 jax@bar.com error:5.7.0:550 Address invalid
1005 @baz.org jane@example.net
1007 then mail addressed to info@foo.com will be sent to the
1008 address foo-info, mail addressed to info@bar.com will be
1009 delivered to bar-info, and mail addressed to anyone at baz.org
1010 will be sent to jane@example.net, mail to joe@bar.com will
1011 be rejected with the specified error message, and mail to
1012 jax@bar.com will also have a RFC 1893 compliant error code
1015 The username from the original address is passed
1018 @foo.org %1@example.com
1020 meaning someone@foo.org will be sent to someone@example.com.
1021 Additionally, if the local part consists of "user+detail"
1022 then "detail" is passed as %2 and "+detail" is passed as %3
1023 when a match against user+* is attempted, so entries like
1025 old+*@foo.org new+%2@example.com
1026 gen+*@foo.org %2@example.com
1027 +*@foo.org %1%3@example.com
1028 X++@foo.org Z%3@example.com
1031 and other forms are possible. Note: to preserve "+detail"
1032 for a default case (@domain) %1%3 must be used as RHS.
1033 There are two wildcards after "+": "+" matches only a non-empty
1034 detail, "*" matches also empty details, e.g., user+@foo.org
1035 matches +*@foo.org but not ++@foo.org. This can be used
1036 to ensure that the parameters %2 and %3 are not empty.
1038 All the host names on the left hand side (foo.com, bar.com,
1039 and baz.org) must be in class {w} or class {VirtHost}. The
1040 latter can be defined by the macros VIRTUSER_DOMAIN or
1041 VIRTUSER_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1042 MASQUERADE_DOMAIN_FILE, see below). If VIRTUSER_DOMAIN or
1043 VIRTUSER_DOMAIN_FILE is used, then the entries of class
1044 {VirtHost} are added to class {R}, i.e., relaying is allowed
1045 to (and from) those domains, which by default includes also
1046 all subdomains (see relay_hosts_only). The default map
1049 hash /etc/mail/virtusertable
1051 A new definition can be specified as the second argument of
1052 the FEATURE macro, such as
1054 FEATURE(`virtusertable', `dbm /etc/mail/virtusers')
1056 virtuser_entire_domain
1057 If the virtusertable is enabled and VIRTUSER_DOMAIN or
1058 VIRTUSER_DOMAIN_FILE is used, this feature will cause
1059 addresses to be searched in the map if their domain
1060 parts are subdomains of elements in class {VirtHost}.
1062 ldap_routing Implement LDAP-based e-mail recipient routing according to
1063 the Internet Draft draft-lachman-laser-ldap-mail-routing-01.
1064 This provides a method to re-route addresses with a
1065 domain portion in class {LDAPRoute} to either a
1066 different mail host or a different address. Hosts can
1067 be added to this class using LDAPROUTE_DOMAIN and
1068 LDAPROUTE_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1069 MASQUERADE_DOMAIN_FILE, see below).
1071 See the LDAP ROUTING section below for more information.
1073 nullclient This is a special case -- it creates a configuration file
1074 containing nothing but support for forwarding all mail to a
1075 central hub via a local SMTP-based network. The argument
1076 is the name of that hub.
1078 The only other feature that should be used in conjunction
1079 with this one is FEATURE(`nocanonify'). No mailers
1080 should be defined. No aliasing or forwarding is done.
1082 local_lmtp Use an LMTP capable local mailer. The argument to this
1083 feature is the pathname of an LMTP capable mailer. By
1084 default, mail.local is used. This is expected to be the
1085 mail.local which came with the 8.9 distribution which is
1086 LMTP capable. The path to mail.local is set by the
1087 confEBINDIR m4 variable -- making the default
1088 LOCAL_MAILER_PATH /usr/libexec/mail.local.
1089 If a different LMTP capable mailer is used, its pathname
1090 can be specified as second parameter and the arguments
1091 passed to it (A=) as third parameter, e.g.,
1093 FEATURE(`local_lmtp', `/usr/local/bin/lmtp', `lmtp')
1095 WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
1096 i.e., without respecting any definitions in an OSTYPE setting.
1098 local_procmail Use procmail or another delivery agent as the local mailer.
1099 The argument to this feature is the pathname of the
1100 delivery agent, which defaults to PROCMAIL_MAILER_PATH.
1101 Note that this does NOT use PROCMAIL_MAILER_FLAGS or
1102 PROCMAIL_MAILER_ARGS for the local mailer; tweak
1103 LOCAL_MAILER_FLAGS and LOCAL_MAILER_ARGS instead, or
1104 specify the appropriate parameters. When procmail is used,
1105 the local mailer can make use of the
1106 "user+indicator@local.host" syntax; normally the +indicator
1107 is just tossed, but by default it is passed as the -a
1108 argument to procmail.
1110 This feature can take up to three arguments:
1112 1. Path to the mailer program
1113 [default: /usr/local/bin/procmail]
1114 2. Argument vector including name of the program
1115 [default: procmail -Y -a $h -d $u]
1116 3. Flags for the mailer [default: SPfhn9]
1118 Empty arguments cause the defaults to be taken.
1119 Note that if you are on a system with a broken
1120 setreuid() call, you may need to add -f $f to the procmail
1121 argument vector to pass the proper sender to procmail.
1123 For example, this allows it to use the maildrop
1124 (http://www.flounder.net/~mrsam/maildrop/) mailer instead
1127 FEATURE(`local_procmail', `/usr/local/bin/maildrop',
1132 FEATURE(`local_procmail', `/usr/local/bin/scanmails')
1134 WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
1135 i.e., without respecting any definitions in an OSTYPE setting.
1137 bestmx_is_local Accept mail as though locally addressed for any host that
1138 lists us as the best possible MX record. This generates
1139 additional DNS traffic, but should be OK for low to
1140 medium traffic hosts. The argument may be a set of
1141 domains, which will limit the feature to only apply to
1142 these domains -- this will reduce unnecessary DNS
1143 traffic. THIS FEATURE IS FUNDAMENTALLY INCOMPATIBLE WITH
1144 WILDCARD MX RECORDS!!! If you have a wildcard MX record
1145 that matches your domain, you cannot use this feature.
1147 smrsh Use the SendMail Restricted SHell (smrsh) provided
1148 with the distribution instead of /bin/sh for mailing
1149 to programs. This improves the ability of the local
1150 system administrator to control what gets run via
1151 e-mail. If an argument is provided it is used as the
1152 pathname to smrsh; otherwise, the path defined by
1153 confEBINDIR is used for the smrsh binary -- by default,
1154 /usr/libexec/smrsh is assumed.
1157 By default, the sendmail configuration files do not permit
1158 mail relaying (that is, accepting mail from outside your
1159 local host (class {w}) and sending it to another host than
1160 your local host). This option sets your site to allow
1161 mail relaying from any site to any site. In almost all
1162 cases, it is better to control relaying more carefully
1163 with the access map, class {R}, or authentication. Domains
1164 can be added to class {R} by the macros RELAY_DOMAIN or
1165 RELAY_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1166 MASQUERADE_DOMAIN_FILE, see below).
1169 This option allows any host in your domain as defined by
1170 class {m} to use your server for relaying. Notice: make
1171 sure that your domain is not just a top level domain,
1172 e.g., com. This can happen if you give your host a name
1173 like example.com instead of host.example.com.
1176 By default, names that are listed as RELAY in the access
1177 db and class {R} are treated as domain names, not host names.
1178 For example, if you specify ``foo.com'', then mail to or
1179 from foo.com, abc.foo.com, or a.very.deep.domain.foo.com
1180 will all be accepted for relaying. This feature changes
1181 the behaviour to look up individual host names only.
1184 Turns on the ability to allow relaying based on the MX
1185 records of the host portion of an incoming recipient; that
1186 is, if an MX record for host foo.com points to your site,
1187 you will accept and relay mail addressed to foo.com. See
1188 description below for more information before using this
1189 feature. Also, see the KNOWNBUGS entry regarding bestmx
1192 FEATURE(`relay_based_on_MX') does not necessarily allow
1193 routing of these messages which you expect to be allowed,
1194 if route address syntax (or %-hack syntax) is used. If
1195 this is a problem, add entries to the access-table or use
1196 FEATURE(`loose_relay_check').
1199 Allows relaying if the mail sender is listed as RELAY in
1200 the access map. If an optional argument `domain' (this
1201 is the literal word `domain', not a placeholder) is given,
1202 relaying can be allowed just based on the domain portion
1203 of the sender address. This feature should only be used if
1204 absolutely necessary as the sender address can be easily
1205 forged. Use of this feature requires the "From:" tag to
1206 be used for the key in the access map; see the discussion
1207 of tags and FEATURE(`relay_mail_from') in the section on
1208 anti-spam configuration control.
1211 Allows relaying if the domain portion of the mail sender
1212 is a local host. This should only be used if absolutely
1213 necessary as it opens a window for spammers. Specifically,
1214 they can send mail to your mail server that claims to be
1215 from your domain (either directly or via a routed address),
1216 and you will go ahead and relay it out to arbitrary hosts
1219 accept_unqualified_senders
1220 Normally, MAIL FROM: commands in the SMTP session will be
1221 refused if the connection is a network connection and the
1222 sender address does not include a domain name. If your
1223 setup sends local mail unqualified (i.e., MAIL FROM:<joe>),
1224 you will need to use this feature to accept unqualified
1225 sender addresses. Setting the DaemonPortOptions modifier
1226 'u' overrides the default behavior, i.e., unqualified
1227 addresses are accepted even without this FEATURE.
1228 If this FEATURE is not used, the DaemonPortOptions modifier
1229 'f' can be used to enforce fully qualified addresses.
1231 accept_unresolvable_domains
1232 Normally, MAIL FROM: commands in the SMTP session will be
1233 refused if the host part of the argument to MAIL FROM:
1234 cannot be located in the host name service (e.g., an A or
1235 MX record in DNS). If you are inside a firewall that has
1236 only a limited view of the Internet host name space, this
1237 could cause problems. In this case you probably want to
1238 use this feature to accept all domains on input, even if
1239 they are unresolvable.
1241 access_db Turns on the access database feature. The access db gives
1242 you the ability to allow or refuse to accept mail from
1243 specified domains for administrative reasons. Moreover,
1244 it can control the behavior of sendmail in various situations.
1245 By default, the access database specification is:
1247 hash -T<TMPF> /etc/mail/access
1249 See the anti-spam configuration control section for further
1250 important information about this feature. Notice:
1251 "-T<TMPF>" is meant literal, do not replace it by anything.
1253 blocklist_recipients
1254 Turns on the ability to block incoming mail for certain
1255 recipient usernames, hostnames, or addresses. For
1256 example, you can block incoming mail to user nobody,
1257 host foo.mydomain.com, or guest@bar.mydomain.com.
1258 These specifications are put in the access db as
1259 described in the anti-spam configuration control section
1260 later in this document.
1262 delay_checks The rulesets check_mail and check_relay will not be called
1263 when a client connects or issues a MAIL command, respectively.
1264 Instead, those rulesets will be called by the check_rcpt
1265 ruleset; they will be skipped under certain circumstances.
1266 See "Delay all checks" in the anti-spam configuration control
1267 section. Note: this feature is incompatible to the versions
1270 use_client_ptr If this feature is enabled then check_relay will override
1271 its first argument with $&{client_ptr}. This is useful for
1272 rejections based on the unverified hostname of client,
1273 which turns on the same behavior as in earlier sendmail
1274 versions when delay_checks was not in use. See doc/op/op.*
1275 about check_relay, {client_name}, and {client_ptr}.
1277 dnsbl Turns on rejection, discarding, or quarantining of hosts
1278 found in a DNS based list. The first argument is used as
1279 the domain in which blocked hosts are listed. A second
1280 argument can be used to change the default error message,
1281 or select one of the operations `discard' and `quarantine'.
1282 Without that second argument, the error message will be
1284 Rejected: IP-ADDRESS listed at SERVER
1286 where IP-ADDRESS and SERVER are replaced by the appropriate
1287 information. By default, temporary lookup failures are
1288 ignored. This behavior can be changed by specifying a
1289 third argument, which must be either `t' or a full error
1290 message. See the anti-spam configuration control section for
1291 an example. The dnsbl feature can be included several times
1292 to query different DNS based rejection lists. See also
1293 enhdnsbl for an enhanced version.
1295 Set the DNSBL_MAP mc option to change the default map
1296 definition from `host'. Set the DNSBL_MAP_OPT mc option
1297 to add additional options to the map specification used.
1299 Some DNS based rejection lists cause failures if asked
1300 for AAAA records. If your sendmail version is compiled
1301 with IPv6 support (NETINET6) and you experience this
1304 define(`DNSBL_MAP', `dns -R A')
1306 before the first use of this feature. Alternatively you
1307 can use enhdnsbl instead (see below). Moreover, this
1308 statement can be used to reduce the number of DNS retries,
1311 define(`DNSBL_MAP', `dns -R A -r2')
1313 See below (EDNSBL_TO) for an explanation.
1315 enhdnsbl Enhanced version of dnsbl (see above). Further arguments
1316 (up to 5) can be used to specify specific return values
1317 from lookups. Temporary lookup failures are ignored unless
1318 a third argument is given, which must be either `t' or a full
1319 error message. By default, any successful lookup will
1320 generate an error. Otherwise the result of the lookup is
1321 compared with the supplied argument(s), and only if a match
1322 occurs an error is generated. For example,
1324 FEATURE(`enhdnsbl', `dnsbl.example.com', `', `t', `127.0.0.2.')
1326 will reject the e-mail if the lookup returns the value
1327 ``127.0.0.2.'', or generate a 451 response if the lookup
1328 temporarily failed. The arguments can contain metasymbols
1329 as they are allowed in the LHS of rules. As the example
1330 shows, the default values are also used if an empty argument,
1331 i.e., `', is specified. This feature requires that sendmail
1332 has been compiled with the flag DNSMAP (see sendmail/README).
1334 Set the EDNSBL_TO mc option to change the DNS retry count
1335 from the default value of 5, this can be very useful when
1336 a DNS server is not responding, which in turn may cause
1337 clients to time out (an entry stating
1339 did not issue MAIL/EXPN/VRFY/ETRN
1343 ratecontrol Enable simple ruleset to do connection rate control
1344 checking. This requires entries in access_db of the form
1346 ClientRate:IP.ADD.RE.SS LIMIT
1348 The RHS specifies the maximum number of connections
1349 (an integer number) over the time interval defined
1350 by ConnectionRateWindowSize, where 0 means unlimited.
1352 Take the following example:
1354 ClientRate:10.1.2.3 4
1355 ClientRate:127.0.0.1 0
1358 10.1.2.3 can only make up to 4 connections, the
1359 general limit it 10, and 127.0.0.1 can make an unlimited
1360 number of connections per ConnectionRateWindowSize.
1362 See also CONNECTION CONTROL.
1364 conncontrol Enable a simple check of the number of incoming SMTP
1365 connections. This requires entries in access_db of the
1368 ClientConn:IP.ADD.RE.SS LIMIT
1370 The RHS specifies the maximum number of open connections
1371 (an integer number).
1373 Take the following example:
1375 ClientConn:10.1.2.3 4
1376 ClientConn:127.0.0.1 0
1379 10.1.2.3 can only have up to 4 open connections, the
1380 general limit it 10, and 127.0.0.1 does not have any
1383 See also CONNECTION CONTROL.
1385 mtamark Experimental support for "Marking Mail Transfer Agents in
1386 Reverse DNS with TXT RRs" (MTAMark), see
1387 draft-stumpf-dns-mtamark-01. Optional arguments are:
1389 1. Error message, default:
1391 550 Rejected: $&{client_addr} not listed as MTA
1393 2. Temporary lookup failures are ignored unless a second
1394 argument is given, which must be either `t' or a full
1397 3. Lookup prefix, default: _perm._smtp._srv. This should
1398 not be changed unless the draft changes it.
1402 FEATURE(`mtamark', `', `t')
1404 lookupdotdomain Look up also .domain in the access map. This allows to
1405 match only subdomains. It does not work well with
1406 FEATURE(`relay_hosts_only'), because most lookups for
1407 subdomains are suppressed by the latter feature.
1410 Normally, if % addressing is used for a recipient, e.g.
1411 user%site@othersite, and othersite is in class {R}, the
1412 check_rcpt ruleset will strip @othersite and recheck
1413 user@site for relaying. This feature changes that
1414 behavior. It should not be needed for most installations.
1416 authinfo Provide a separate map for client side authentication
1417 information. See SMTP AUTHENTICATION for details.
1418 By default, the authinfo database specification is:
1420 hash /etc/mail/authinfo
1423 Preserve the name of the recipient host if LUSER_RELAY is
1424 used. Without this option, the domain part of the
1425 recipient address will be replaced by the host specified as
1426 LUSER_RELAY. This feature only works if the hostname is
1427 passed to the mailer (see mailer triple in op.me). Note
1428 that in the default configuration the local mailer does not
1429 receive the hostname, i.e., the mailer triple has an empty
1432 preserve_local_plus_detail
1433 Preserve the +detail portion of the address when passing
1434 address to local delivery agent. Disables alias and
1435 .forward +detail stripping (e.g., given user+detail, only
1436 that address will be looked up in the alias file; user+* and
1437 user will not be looked up). Only use if the local
1438 delivery agent in use supports +detail addressing.
1439 Moreover, this will most likely not work if the 'w' flag
1440 for the local mailer is set as the entire local address
1441 including +detail is passed to the user lookup function.
1443 compat_check Enable ruleset check_compat to look up pairs of addresses
1444 with the Compat: tag -- Compat:sender<@>recipient -- in the
1445 access map. Valid values for the RHS include
1446 DISCARD silently discard recipient
1447 TEMP: return a temporary error
1448 ERROR: return a permanent error
1449 In the last two cases, a 4xy/5xy SMTP reply code should
1452 no_default_msa Don't generate the default MSA daemon, i.e.,
1453 DAEMON_OPTIONS(`Port=587,Name=MSA,M=E')
1454 To define a MSA daemon with other parameters, use this
1455 FEATURE and introduce new settings via DAEMON_OPTIONS().
1457 msp Defines config file for Message Submission Program.
1458 See sendmail/SECURITY for details and cf/cf/submit.mc how
1459 to use it. An optional argument can be used to override
1460 the default of `[localhost]' to use as host to send all
1461 e-mails to. Note that MX records will be used if the
1462 specified hostname is not in square brackets (e.g.,
1463 [hostname]). If `MSA' is specified as second argument then
1464 port 587 is used to contact the server. Example:
1466 FEATURE(`msp', `', `MSA')
1468 Some more hints about possible changes can be found below
1469 in the section MESSAGE SUBMISSION PROGRAM.
1471 Note: Due to many problems, submit.mc uses
1473 FEATURE(`msp', `[127.0.0.1]')
1475 by default. If you have a machine with IPv6 only,
1478 FEATURE(`msp', `[IPv6:0:0:0:0:0:0:0:1]')
1480 If you want to continue using '[localhost]', (the behavior
1485 queuegroup A simple example how to select a queue group based
1486 on the full e-mail address or the domain of the
1487 recipient. Selection is done via entries in the
1488 access map using the tag QGRP:, for example:
1490 QGRP:example.com main
1491 QGRP:friend@some.org others
1492 QGRP:my.domain local
1494 where "main", "others", and "local" are names of
1495 queue groups. If an argument is specified, it is used
1496 as default queue group.
1498 Note: please read the warning in doc/op/op.me about
1499 queue groups and possible queue manipulations.
1501 greet_pause Adds the greet_pause ruleset which enables open proxy
1502 and SMTP slamming protection. The feature can take an
1503 argument specifying the milliseconds to wait:
1505 FEATURE(`greet_pause', `5000') dnl 5 seconds
1507 If FEATURE(`access_db') is enabled, an access database
1508 lookup with the GreetPause tag is done using client
1509 hostname, domain, IP address, or subnet to determine the
1512 GreetPause:my.domain 0
1513 GreetPause:example.com 5000
1514 GreetPause:10.1.2 2000
1515 GreetPause:127.0.0.1 0
1517 When using FEATURE(`access_db'), the optional
1518 FEATURE(`greet_pause') argument becomes the default if
1519 nothing is found in the access database. A ruleset called
1520 Local_greet_pause can be used for local modifications, e.g.,
1524 R$* $: $&{daemon_flags}
1527 block_bad_helo Reject messages from SMTP clients which provide a HELO/EHLO
1528 argument which is either unqualified, or is one of our own
1529 names (i.e., the server name instead of the client name).
1530 This check is performed at RCPT stage and disabled for the
1532 - authenticated sessions,
1533 - connections from IP addresses in class $={R}.
1534 Currently access_db lookups can not be used to
1535 (selectively) disable this test, moreover,
1537 FEATURE(`delay_checks')
1539 is required. Note, the block_bad_helo feature automatically
1540 adds the IPv6 and IPv4 localhost IP addresses to $={w} (local
1541 host names) and $={R} (relay permitted).
1543 require_rdns Reject mail from connecting SMTP clients without proper
1544 rDNS (reverse DNS), functional gethostbyaddr() resolution.
1545 Note: this feature will cause false positives, i.e., there
1546 are legitimate MTAs that do not have proper DNS entries.
1547 Rejecting mails from those MTAs is a local policy decision.
1549 The basic policy is to reject message with a 5xx error if
1550 the IP address fails to resolve. However, if this is a
1551 temporary failure, a 4xx temporary failure is returned.
1552 If the look-up succeeds, but returns an apparently forged
1553 value, this is treated as a temporary failure with a 4xx
1558 Exceptions based on access entries are discussed below.
1559 Any IP address matched using $=R (the "relay-domains" file)
1560 is excepted from the rules. Since we have explicitly
1561 allowed relaying for this host, based on IP address, we
1562 ignore the rDNS failure.
1564 The philosophical assumption here is that most users do
1565 not control their rDNS. They should be able to send mail
1566 through their ISP, whether or not they have valid rDNS.
1567 The class $=R, roughly speaking, contains those IP addresses
1568 and address ranges for which we are the ISP, or are acting
1571 If `delay_checks' is in effect (recommended), then any
1572 sender who has authenticated is also excepted from the
1573 restrictions. This happens because the rules produced by
1574 this FEATURE() will not be applied to authenticated senders
1575 (assuming `delay_checks').
1582 will allowlist IP address 1.2.3.4, so that the rDNS
1583 blocking does apply to that IP address
1586 Connect:1.2.3.4 REJECT
1587 will have the effect of forcing a temporary failure for
1588 that address to be treated as a permanent failure.
1590 badmx Reject envelope sender addresses (MAIL) whose domain part
1591 resolves to a "bad" MX record. By default these are
1592 MX records which resolve to A records that match the
1595 ^(127\.|10\.|0\.0\.0\.0)
1597 This default regular expression can be overridden by
1598 specifying an argument, e.g.,
1600 FEATURE(`badmx', `^127\.0\.0\.1')
1602 Note: this feature requires that the sendmail binary
1603 has been compiled with the options MAP_REGEX and
1610 Some things just can't be called features. To make this clear,
1611 they go in the hack subdirectory and are referenced using the HACK
1612 macro. These will tend to be site-dependent. The release
1613 includes the Berkeley-dependent "cssubdomain" hack (that makes
1614 sendmail accept local names in either Berkeley.EDU or CS.Berkeley.EDU;
1615 this is intended as a short-term aid while moving hosts into
1619 +--------------------+
1620 | SITE CONFIGURATION |
1621 +--------------------+
1623 *****************************************************
1624 * This section is really obsolete, and is preserved *
1625 * only for back compatibility. You should plan on *
1626 * using mailertables for new installations. In *
1627 * particular, it doesn't work for the newer forms *
1628 * of UUCP mailers, such as uucp-uudom. *
1629 *****************************************************
1631 Complex sites will need more local configuration information, such as
1632 lists of UUCP hosts they speak with directly. This can get a bit more
1633 tricky. For an example of a "complex" site, see cf/ucbvax.mc.
1635 The SITECONFIG macro allows you to indirectly reference site-dependent
1636 configuration information stored in the siteconfig subdirectory. For
1639 SITECONFIG(`uucp.ucbvax', `ucbvax', `U')
1641 reads the file uucp.ucbvax for local connection information. The
1642 second parameter is the local name (in this case just "ucbvax" since
1643 it is locally connected, and hence a UUCP hostname). The third
1644 parameter is the name of both a macro to store the local name (in
1645 this case, {U}) and the name of the class (e.g., {U}) in which to store
1646 the host information read from the file. Another SITECONFIG line reads
1648 SITECONFIG(`uucp.ucbarpa', `ucbarpa.Berkeley.EDU', `W')
1650 This says that the file uucp.ucbarpa contains the list of UUCP sites
1651 connected to ucbarpa.Berkeley.EDU. Class {W} will be used to
1652 store this list, and $W is defined to be ucbarpa.Berkeley.EDU, that
1653 is, the name of the relay to which the hosts listed in uucp.ucbarpa
1654 are connected. [The machine ucbarpa is gone now, but this
1655 out-of-date configuration file has been left around to demonstrate
1656 how you might do this.]
1658 Note that the case of SITECONFIG with a third parameter of ``U'' is
1659 special; the second parameter is assumed to be the UUCP name of the
1660 local site, rather than the name of a remote site, and the UUCP name
1661 is entered into class {w} (the list of local hostnames) as $U.UUCP.
1663 The siteconfig file (e.g., siteconfig/uucp.ucbvax.m4) contains nothing
1664 more than a sequence of SITE macros describing connectivity. For
1670 The second example demonstrates that you can use two names on the
1671 same line; these are usually aliases for the same host (or are at
1672 least in the same company).
1674 The macro LOCAL_UUCP can be used to add rules into the generated
1675 cf file at the place where MAILER(`uucp') inserts its rules. This
1676 should only be used if really necessary.
1678 +--------------------+
1679 | USING UUCP MAILERS |
1680 +--------------------+
1682 It's hard to get UUCP mailers right because of the extremely ad hoc
1683 nature of UUCP addressing. These config files are really designed
1684 for domain-based addressing, even for UUCP sites.
1686 There are four UUCP mailers available. The choice of which one to
1687 use is partly a matter of local preferences and what is running at
1688 the other end of your UUCP connection. Unlike good protocols that
1689 define what will go over the wire, UUCP uses the policy that you
1690 should do what is right for the other end; if they change, you have
1691 to change. This makes it hard to do the right thing, and discourages
1692 people from updating their software. In general, if you can avoid
1695 The major choice is whether to go for a domainized scheme or a
1696 non-domainized scheme. This depends entirely on what the other
1697 end will recognize. If at all possible, you should encourage the
1698 other end to go to a domain-based system -- non-domainized addresses
1699 don't work entirely properly.
1701 The four mailers are:
1703 uucp-old (obsolete name: "uucp")
1704 This is the oldest, the worst (but the closest to UUCP) way of
1705 sending messages across UUCP connections. It does bangify
1706 everything and prepends $U (your UUCP name) to the sender's
1707 address (which can already be a bang path itself). It can
1708 only send to one address at a time, so it spends a lot of
1709 time copying duplicates of messages. Avoid this if at all
1712 uucp-new (obsolete name: "suucp")
1713 The same as above, except that it assumes that in one rmail
1714 command you can specify several recipients. It still has a
1715 lot of other problems.
1718 This UUCP mailer keeps everything as domain addresses.
1719 Basically, it uses the SMTP mailer rewriting rules. This mailer
1720 is only included if MAILER(`smtp') is specified before
1723 Unfortunately, a lot of UUCP mailer transport agents require
1724 bangified addresses in the envelope, although you can use
1725 domain-based addresses in the message header. (The envelope
1726 shows up as the From_ line on UNIX mail.) So....
1729 This is a cross between uucp-new (for the envelope addresses)
1730 and uucp-dom (for the header addresses). It bangifies the
1731 envelope sender (From_ line in messages) without adding the
1732 local hostname, unless there is no host name on the address
1733 at all (e.g., "wolf") or the host component is a UUCP host name
1734 instead of a domain name ("somehost!wolf" instead of
1735 "some.dom.ain!wolf"). This is also included only if MAILER(`smtp')
1736 is also specified earlier.
1740 On host grasp.insa-lyon.fr (UUCP host name "grasp"), the following
1741 summarizes the sender rewriting for various mailers.
1743 Mailer sender rewriting in the envelope
1744 ------ ------ -------------------------
1745 uucp-{old,new} wolf grasp!wolf
1746 uucp-dom wolf wolf@grasp.insa-lyon.fr
1747 uucp-uudom wolf grasp.insa-lyon.fr!wolf
1749 uucp-{old,new} wolf@fr.net grasp!fr.net!wolf
1750 uucp-dom wolf@fr.net wolf@fr.net
1751 uucp-uudom wolf@fr.net fr.net!wolf
1753 uucp-{old,new} somehost!wolf grasp!somehost!wolf
1754 uucp-dom somehost!wolf somehost!wolf@grasp.insa-lyon.fr
1755 uucp-uudom somehost!wolf grasp.insa-lyon.fr!somehost!wolf
1757 If you are using one of the domainized UUCP mailers, you really want
1758 to convert all UUCP addresses to domain format -- otherwise, it will
1759 do it for you (and probably not the way you expected). For example,
1760 if you have the address foo!bar!baz (and you are not sending to foo),
1761 the heuristics will add the @uucp.relay.name or @local.host.name to
1762 this address. However, if you map foo to foo.host.name first, it
1763 will not add the local hostname. You can do this using the uucpdomain
1767 +-------------------+
1768 | TWEAKING RULESETS |
1769 +-------------------+
1771 For more complex configurations, you can define special rules.
1772 The macro LOCAL_RULE_3 introduces rules that are used in canonicalizing
1773 the names. Any modifications made here are reflected in the header.
1775 A common use is to convert old UUCP addresses to SMTP addresses using
1776 the UUCPSMTP macro. For example:
1779 UUCPSMTP(`decvax', `decvax.dec.com')
1780 UUCPSMTP(`research', `research.att.com')
1782 will cause addresses of the form "decvax!user" and "research!user"
1783 to be converted to "user@decvax.dec.com" and "user@research.att.com"
1786 This could also be used to look up hosts in a database map:
1789 R$* < @ $+ > $* $: $1 < @ $(hostmap $2 $) > $3
1791 This map would be defined in the LOCAL_CONFIG portion, as shown below.
1793 Similarly, LOCAL_RULE_0 can be used to introduce new parsing rules.
1794 For example, new rules are needed to parse hostnames that you accept
1795 via MX records. For example, you might have:
1798 R$+ <@ host.dom.ain.> $#uucp $@ cnmat $: $1 < @ host.dom.ain.>
1800 You would use this if you had installed an MX record for cnmat.Berkeley.EDU
1801 pointing at this host; this rule catches the message and forwards it on
1804 You can also tweak rulesets 1 and 2 using LOCAL_RULE_1 and LOCAL_RULE_2.
1805 These rulesets are normally empty.
1807 A similar macro is LOCAL_CONFIG. This introduces lines added after the
1808 boilerplate option setting but before rulesets. Do not declare rulesets in
1809 the LOCAL_CONFIG section. It can be used to declare local database maps or
1810 whatever. For example:
1813 Khostmap hash /etc/mail/hostmap
1814 Kyplocal nis -m hosts.byname
1817 +---------------------------+
1818 | MASQUERADING AND RELAYING |
1819 +---------------------------+
1821 You can have your host masquerade as another using
1823 MASQUERADE_AS(`host.domain')
1825 This causes mail being sent to be labeled as coming from the
1826 indicated host.domain, rather than $j. One normally masquerades as
1827 one of one's own subdomains (for example, it's unlikely that
1828 Berkeley would choose to masquerade as an MIT site). This
1829 behaviour is modified by a plethora of FEATUREs; in particular, see
1830 masquerade_envelope, allmasquerade, limited_masquerade, and
1831 masquerade_entire_domain.
1833 The masquerade name is not normally canonified, so it is important
1834 that it be your One True Name, that is, fully qualified and not a
1835 CNAME. However, if you use a CNAME, the receiving side may canonify
1836 it for you, so don't think you can cheat CNAME mapping this way.
1838 Normally the only addresses that are masqueraded are those that come
1839 from this host (that is, are either unqualified or in class {w}, the list
1840 of local domain names). You can augment this list, which is realized
1843 MASQUERADE_DOMAIN(`otherhost.domain')
1845 The effect of this is that although mail to user@otherhost.domain
1846 will not be delivered locally, any mail including any user@otherhost.domain
1847 will, when relayed, be rewritten to have the MASQUERADE_AS address.
1848 This can be a space-separated list of names.
1850 If these names are in a file, you can use
1852 MASQUERADE_DOMAIN_FILE(`filename')
1854 to read the list of names from the indicated file (i.e., to add
1855 elements to class {M}).
1857 To exempt hosts or subdomains from being masqueraded, you can use
1859 MASQUERADE_EXCEPTION(`host.domain')
1861 This can come handy if you want to masquerade a whole domain
1862 except for one (or a few) host(s). If these names are in a file,
1865 MASQUERADE_EXCEPTION_FILE(`filename')
1867 Normally only header addresses are masqueraded. If you want to
1868 masquerade the envelope as well, use
1870 FEATURE(`masquerade_envelope')
1872 There are always users that need to be "exposed" -- that is, their
1873 internal site name should be displayed instead of the masquerade name.
1874 Root is an example (which has been "exposed" by default prior to 8.10).
1875 You can add users to this list using
1877 EXPOSED_USER(`usernames')
1879 This adds users to class {E}; you could also use
1881 EXPOSED_USER_FILE(`filename')
1883 You can also arrange to relay all unqualified names (that is, names
1884 without @host) to a relay host. For example, if you have a central
1885 email server, you might relay to that host so that users don't have
1886 to have .forward files or aliases. You can do this using
1888 define(`LOCAL_RELAY', `mailer:hostname')
1890 The ``mailer:'' can be omitted, in which case the mailer defaults to
1891 "relay". There are some user names that you don't want relayed, perhaps
1892 because of local aliases. A common example is root, which may be
1893 locally aliased. You can add entries to this list using
1895 LOCAL_USER(`usernames')
1897 This adds users to class {L}; you could also use
1899 LOCAL_USER_FILE(`filename')
1901 If you want all incoming mail sent to a centralized hub, as for a
1902 shared /var/spool/mail scheme, use
1904 define(`MAIL_HUB', `mailer:hostname')
1906 Again, ``mailer:'' defaults to "relay". If you define both LOCAL_RELAY
1907 and MAIL_HUB _AND_ you have FEATURE(`stickyhost'), unqualified names will
1908 be sent to the LOCAL_RELAY and other local names will be sent to MAIL_HUB.
1909 Note: there is a (long standing) bug which keeps this combination from
1910 working for addresses of the form user+detail.
1911 Names in class {L} will be delivered locally, so you MUST have aliases or
1912 .forward files for them.
1914 For example, if you are on machine mastodon.CS.Berkeley.EDU and you have
1915 FEATURE(`stickyhost'), the following combinations of settings will have the
1918 email sent to.... eric eric@mastodon.CS.Berkeley.EDU
1920 LOCAL_RELAY set to mail.CS.Berkeley.EDU (delivered locally)
1921 mail.CS.Berkeley.EDU (no local aliasing) (aliasing done)
1923 MAIL_HUB set to mammoth.CS.Berkeley.EDU mammoth.CS.Berkeley.EDU
1924 mammoth.CS.Berkeley.EDU (aliasing done) (aliasing done)
1926 Both LOCAL_RELAY and mail.CS.Berkeley.EDU mammoth.CS.Berkeley.EDU
1927 MAIL_HUB set as above (no local aliasing) (aliasing done)
1929 If you do not have FEATURE(`stickyhost') set, then LOCAL_RELAY and
1930 MAIL_HUB act identically, with MAIL_HUB taking precedence.
1932 If you want all outgoing mail to go to a central relay site, define
1933 SMART_HOST as well. Briefly:
1935 LOCAL_RELAY applies to unqualified names (e.g., "eric").
1936 MAIL_HUB applies to names qualified with the name of the
1937 local host (e.g., "eric@mastodon.CS.Berkeley.EDU").
1938 SMART_HOST applies to names qualified with other hosts or
1939 bracketed addresses (e.g., "eric@mastodon.CS.Berkeley.EDU"
1940 or "eric@[127.0.0.1]").
1942 However, beware that other relays (e.g., UUCP_RELAY, BITNET_RELAY,
1943 DECNET_RELAY, and FAX_RELAY) take precedence over SMART_HOST, so if you
1944 really want absolutely everything to go to a single central site you will
1945 need to unset all the other relays -- or better yet, find or build a
1946 minimal config file that does this.
1948 For duplicate suppression to work properly, the host name is best
1949 specified with a terminal dot:
1951 define(`MAIL_HUB', `host.domain.')
1952 note the trailing dot ---^
1955 +-------------------------------------------+
1956 | USING LDAP FOR ALIASES, MAPS, AND CLASSES |
1957 +-------------------------------------------+
1959 LDAP can be used for aliases, maps, and classes by either specifying your
1960 own LDAP map specification or using the built-in default LDAP map
1961 specification. The built-in default specifications all provide lookups
1962 which match against either the machine's fully qualified hostname (${j}) or
1963 a "cluster". The cluster allows you to share LDAP entries among a large
1964 number of machines without having to enter each of the machine names into
1965 each LDAP entry. To set the LDAP cluster name to use for a particular
1966 machine or set of machines, set the confLDAP_CLUSTER m4 variable to a
1967 unique name. For example:
1969 define(`confLDAP_CLUSTER', `Servers')
1971 Here, the word `Servers' will be the cluster name. As an example, assume
1972 that smtp.sendmail.org, etrn.sendmail.org, and mx.sendmail.org all belong
1973 to the Servers cluster.
1975 Some of the LDAP LDIF examples below show use of the Servers cluster.
1976 Every entry must have either a sendmailMTAHost or sendmailMTACluster
1977 attribute or it will be ignored. Be careful as mixing clusters and
1978 individual host records can have surprising results (see the CAUTION
1981 See the file cf/sendmail.schema for the actual LDAP schemas. Note that
1982 this schema (and therefore the lookups and examples below) is experimental
1983 at this point as it has had little public review. Therefore, it may change
1984 in future versions. Feedback via sendmail-YYYY@support.sendmail.org is
1985 encouraged (replace YYYY with the current year, e.g., 2005).
1991 The ALIAS_FILE (O AliasFile) option can be set to use LDAP for alias
1992 lookups. To use the default schema, simply use:
1994 define(`ALIAS_FILE', `ldap:')
1996 By doing so, you will use the default schema which expands to a map
1997 declared as follows:
1999 ldap -k (&(objectClass=sendmailMTAAliasObject)
2000 (sendmailMTAAliasGrouping=aliases)
2001 (|(sendmailMTACluster=${sendmailMTACluster})
2002 (sendmailMTAHost=$j))
2003 (sendmailMTAKey=%0))
2004 -v sendmailMTAAliasValue,sendmailMTAAliasSearch:FILTER:sendmailMTAAliasObject,sendmailMTAAliasURL:URL:sendmailMTAAliasObject
2007 NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
2008 used when the binary expands the `ldap:' token as the AliasFile option is
2009 not actually macro-expanded when read from the sendmail.cf file.
2011 Example LDAP LDIF entries might be:
2013 dn: sendmailMTAKey=sendmail-list, dc=sendmail, dc=org
2014 objectClass: sendmailMTA
2015 objectClass: sendmailMTAAlias
2016 objectClass: sendmailMTAAliasObject
2017 sendmailMTAAliasGrouping: aliases
2018 sendmailMTAHost: etrn.sendmail.org
2019 sendmailMTAKey: sendmail-list
2020 sendmailMTAAliasValue: ca@example.org
2021 sendmailMTAAliasValue: eric
2022 sendmailMTAAliasValue: gshapiro@example.com
2024 dn: sendmailMTAKey=owner-sendmail-list, dc=sendmail, dc=org
2025 objectClass: sendmailMTA
2026 objectClass: sendmailMTAAlias
2027 objectClass: sendmailMTAAliasObject
2028 sendmailMTAAliasGrouping: aliases
2029 sendmailMTAHost: etrn.sendmail.org
2030 sendmailMTAKey: owner-sendmail-list
2031 sendmailMTAAliasValue: eric
2033 dn: sendmailMTAKey=postmaster, dc=sendmail, dc=org
2034 objectClass: sendmailMTA
2035 objectClass: sendmailMTAAlias
2036 objectClass: sendmailMTAAliasObject
2037 sendmailMTAAliasGrouping: aliases
2038 sendmailMTACluster: Servers
2039 sendmailMTAKey: postmaster
2040 sendmailMTAAliasValue: eric
2042 Here, the aliases sendmail-list and owner-sendmail-list will be available
2043 only on etrn.sendmail.org but the postmaster alias will be available on
2044 every machine in the Servers cluster (including etrn.sendmail.org).
2046 CAUTION: aliases are additive so that entries like these:
2048 dn: sendmailMTAKey=bob, dc=sendmail, dc=org
2049 objectClass: sendmailMTA
2050 objectClass: sendmailMTAAlias
2051 objectClass: sendmailMTAAliasObject
2052 sendmailMTAAliasGrouping: aliases
2053 sendmailMTACluster: Servers
2055 sendmailMTAAliasValue: eric
2057 dn: sendmailMTAKey=bobetrn, dc=sendmail, dc=org
2058 objectClass: sendmailMTA
2059 objectClass: sendmailMTAAlias
2060 objectClass: sendmailMTAAliasObject
2061 sendmailMTAAliasGrouping: aliases
2062 sendmailMTAHost: etrn.sendmail.org
2064 sendmailMTAAliasValue: gshapiro
2066 would mean that on all of the hosts in the cluster, mail to bob would go to
2067 eric EXCEPT on etrn.sendmail.org in which case it would go to BOTH eric and
2070 If you prefer not to use the default LDAP schema for your aliases, you can
2071 specify the map parameters when setting ALIAS_FILE. For example:
2073 define(`ALIAS_FILE', `ldap:-k (&(objectClass=mailGroup)(mail=%0)) -v mgrpRFC822MailMember')
2079 FEATURE()'s which take an optional map definition argument (e.g., access,
2080 mailertable, virtusertable, etc.) can instead take the special keyword
2083 FEATURE(`access_db', `LDAP')
2084 FEATURE(`virtusertable', `LDAP')
2086 When this keyword is given, that map will use LDAP lookups consisting of
2087 the objectClass sendmailMTAClassObject, the attribute sendmailMTAMapName
2088 with the map name, a search attribute of sendmailMTAKey, and the value
2089 attribute sendmailMTAMapValue.
2091 The values for sendmailMTAMapName are:
2093 FEATURE() sendmailMTAMapName
2094 --------- ------------------
2099 genericstable generics
2101 uucpdomain uucpdomain
2102 virtusertable virtuser
2104 For example, FEATURE(`mailertable', `LDAP') would use the map definition:
2106 Kmailertable ldap -k (&(objectClass=sendmailMTAMapObject)
2107 (sendmailMTAMapName=mailer)
2108 (|(sendmailMTACluster=${sendmailMTACluster})
2109 (sendmailMTAHost=$j))
2110 (sendmailMTAKey=%0))
2111 -1 -v sendmailMTAMapValue,sendmailMTAMapSearch:FILTER:sendmailMTAMapObject,sendmailMTAMapURL:URL:sendmailMTAMapObject
2113 An example LDAP LDIF entry using this map might be:
2115 dn: sendmailMTAMapName=mailer, dc=sendmail, dc=org
2116 objectClass: sendmailMTA
2117 objectClass: sendmailMTAMap
2118 sendmailMTACluster: Servers
2119 sendmailMTAMapName: mailer
2121 dn: sendmailMTAKey=example.com, sendmailMTAMapName=mailer, dc=sendmail, dc=org
2122 objectClass: sendmailMTA
2123 objectClass: sendmailMTAMap
2124 objectClass: sendmailMTAMapObject
2125 sendmailMTAMapName: mailer
2126 sendmailMTACluster: Servers
2127 sendmailMTAKey: example.com
2128 sendmailMTAMapValue: relay:[smtp.example.com]
2130 CAUTION: If your LDAP database contains the record above and *ALSO* a host
2131 specific record such as:
2133 dn: sendmailMTAKey=example.com@etrn, sendmailMTAMapName=mailer, dc=sendmail, dc=org
2134 objectClass: sendmailMTA
2135 objectClass: sendmailMTAMap
2136 objectClass: sendmailMTAMapObject
2137 sendmailMTAMapName: mailer
2138 sendmailMTAHost: etrn.sendmail.org
2139 sendmailMTAKey: example.com
2140 sendmailMTAMapValue: relay:[mx.example.com]
2142 then these entries will give unexpected results. When the lookup is done
2143 on etrn.sendmail.org, the effect is that there is *NO* match at all as maps
2144 require a single match. Since the host etrn.sendmail.org is also in the
2145 Servers cluster, LDAP would return two answers for the example.com map key
2146 in which case sendmail would treat this as no match at all.
2148 If you prefer not to use the default LDAP schema for your maps, you can
2149 specify the map parameters when using the FEATURE(). For example:
2151 FEATURE(`access_db', `ldap:-1 -k (&(objectClass=mapDatabase)(key=%0)) -v value')
2157 Normally, classes can be filled via files or programs. As of 8.12, they
2158 can also be filled via map lookups using a new syntax:
2160 F{ClassName}mapkey@mapclass:mapspec
2162 mapkey is optional and if not provided the map key will be empty. This can
2163 be used with LDAP to read classes from LDAP. Note that the lookup is only
2164 done when sendmail is initially started. Use the special value `@LDAP' to
2165 use the default LDAP schema. For example:
2167 RELAY_DOMAIN_FILE(`@LDAP')
2169 would put all of the attribute sendmailMTAClassValue values of LDAP records
2170 with objectClass sendmailMTAClass and an attribute sendmailMTAClassName of
2171 'R' into class $={R}. In other words, it is equivalent to the LDAP map
2174 F{R}@ldap:-k (&(objectClass=sendmailMTAClass)
2175 (sendmailMTAClassName=R)
2176 (|(sendmailMTACluster=${sendmailMTACluster})
2177 (sendmailMTAHost=$j)))
2178 -v sendmailMTAClassValue,sendmailMTAClassSearch:FILTER:sendmailMTAClass,sendmailMTAClassURL:URL:sendmailMTAClass
2180 NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
2181 used when the binary expands the `@LDAP' token as class declarations are
2182 not actually macro-expanded when read from the sendmail.cf file.
2184 This can be used with class related commands such as RELAY_DOMAIN_FILE(),
2185 MASQUERADE_DOMAIN_FILE(), etc:
2187 Command sendmailMTAClassName
2188 ------- --------------------
2189 CANONIFY_DOMAIN_FILE() Canonify
2190 EXPOSED_USER_FILE() E
2191 GENERICS_DOMAIN_FILE() G
2192 LDAPROUTE_DOMAIN_FILE() LDAPRoute
2193 LDAPROUTE_EQUIVALENT_FILE() LDAPRouteEquiv
2195 MASQUERADE_DOMAIN_FILE() M
2196 MASQUERADE_EXCEPTION_FILE() N
2197 RELAY_DOMAIN_FILE() R
2198 VIRTUSER_DOMAIN_FILE() VirtHost
2200 You can also add your own as any 'F'ile class of the form:
2204 will use "ClassName" for the sendmailMTAClassName.
2206 An example LDAP LDIF entry would look like:
2208 dn: sendmailMTAClassName=R, dc=sendmail, dc=org
2209 objectClass: sendmailMTA
2210 objectClass: sendmailMTAClass
2211 sendmailMTACluster: Servers
2212 sendmailMTAClassName: R
2213 sendmailMTAClassValue: sendmail.org
2214 sendmailMTAClassValue: example.com
2215 sendmailMTAClassValue: 10.56.23
2217 CAUTION: If your LDAP database contains the record above and *ALSO* a host
2218 specific record such as:
2220 dn: sendmailMTAClassName=R@etrn.sendmail.org, dc=sendmail, dc=org
2221 objectClass: sendmailMTA
2222 objectClass: sendmailMTAClass
2223 sendmailMTAHost: etrn.sendmail.org
2224 sendmailMTAClassName: R
2225 sendmailMTAClassValue: example.com
2227 the result will be similar to the aliases caution above. When the lookup
2228 is done on etrn.sendmail.org, $={R} would contain all of the entries (from
2229 both the cluster match and the host match). In other words, the effective
2232 If you prefer not to use the default LDAP schema for your classes, you can
2233 specify the map parameters when using the class command. For example:
2235 VIRTUSER_DOMAIN_FILE(`@ldap:-k (&(objectClass=virtHosts)(host=*)) -v host')
2237 Remember, macros can not be used in a class declaration as the binary does
2245 FEATURE(`ldap_routing') can be used to implement the IETF Internet Draft
2246 LDAP Schema for Intranet Mail Routing
2247 (draft-lachman-laser-ldap-mail-routing-01). This feature enables
2248 LDAP-based rerouting of a particular address to either a different host
2249 or a different address. The LDAP lookup is first attempted on the full
2250 address (e.g., user@example.com) and then on the domain portion
2251 (e.g., @example.com). Be sure to setup your domain for LDAP routing using
2252 LDAPROUTE_DOMAIN(), e.g.:
2254 LDAPROUTE_DOMAIN(`example.com')
2256 Additionally, you can specify equivalent domains for LDAP routing using
2257 LDAPROUTE_EQUIVALENT() and LDAPROUTE_EQUIVALENT_FILE(). 'Equivalent'
2258 hostnames are mapped to $M (the masqueraded hostname for the server) before
2259 the LDAP query. For example, if the mail is addressed to
2260 user@host1.example.com, normally the LDAP lookup would only be done for
2261 'user@host1.example.com' and '@host1.example.com'. However, if
2262 LDAPROUTE_EQUIVALENT(`host1.example.com') is used, the lookups would also be
2263 done on 'user@example.com' and '@example.com' after attempting the
2264 host1.example.com lookups.
2266 By default, the feature will use the schemas as specified in the draft
2267 and will not reject addresses not found by the LDAP lookup. However,
2268 this behavior can be changed by giving additional arguments to the FEATURE()
2271 FEATURE(`ldap_routing', <mailHost>, <mailRoutingAddress>, <bounce>,
2272 <detail>, <nodomain>, <tempfail>)
2274 where <mailHost> is a map definition describing how to look up an alternative
2275 mail host for a particular address; <mailRoutingAddress> is a map definition
2276 describing how to look up an alternative address for a particular address;
2277 the <bounce> argument, if present and not the word "passthru", dictates
2278 that mail should be bounced if neither a mailHost nor mailRoutingAddress
2279 is found, if set to "sendertoo", the sender will be rejected if not
2280 found in LDAP; and <detail> indicates what actions to take if the address
2281 contains +detail information -- `strip' tries the lookup with the +detail
2282 and if no matches are found, strips the +detail and tries the lookup again;
2283 `preserve', does the same as `strip' but if a mailRoutingAddress match is
2284 found, the +detail information is copied to the new address; the <nodomain>
2285 argument, if present, will prevent the @domain lookup if the full
2286 address is not found in LDAP; the <tempfail> argument, if set to
2287 "tempfail", instructs the rules to give an SMTP 4XX temporary
2288 error if the LDAP server gives the MTA a temporary failure, or if set to
2289 "queue" (the default), the MTA will locally queue the mail.
2291 The default <mailHost> map definition is:
2293 ldap -1 -T<TMPF> -v mailHost -k (&(objectClass=inetLocalMailRecipient)
2294 (mailLocalAddress=%0))
2296 The default <mailRoutingAddress> map definition is:
2298 ldap -1 -T<TMPF> -v mailRoutingAddress
2299 -k (&(objectClass=inetLocalMailRecipient)
2300 (mailLocalAddress=%0))
2302 Note that neither includes the LDAP server hostname (-h server) or base DN
2303 (-b o=org,c=COUNTRY), both necessary for LDAP queries. It is presumed that
2304 your .mc file contains a setting for the confLDAP_DEFAULT_SPEC option with
2305 these settings. If this is not the case, the map definitions should be
2306 changed as described above. The "-T<TMPF>" is required in any user
2307 specified map definition to catch temporary errors.
2309 The following possibilities exist as a result of an LDAP lookup on an
2312 mailHost is mailRoutingAddress is Results in
2313 ----------- --------------------- ----------
2314 set to a set mail delivered to
2315 "local" host mailRoutingAddress
2317 set to a not set delivered to
2318 "local" host original address
2320 set to a set mailRoutingAddress
2321 remote host relayed to mailHost
2323 set to a not set original address
2324 remote host relayed to mailHost
2326 not set set mail delivered to
2329 not set not set delivered to
2330 original address *OR*
2331 bounced as unknown user
2333 The term "local" host above means the host specified is in class {w}. If
2334 the result would mean sending the mail to a different host, that host is
2335 looked up in the mailertable before delivery.
2337 Note that the last case depends on whether the third argument is given
2338 to the FEATURE() command. The default is to deliver the message to the
2341 The LDAP entries should be set up with an objectClass of
2342 inetLocalMailRecipient and the address be listed in a mailLocalAddress
2343 attribute. If present, there must be only one mailHost attribute and it
2344 must contain a fully qualified host name as its value. Similarly, if
2345 present, there must be only one mailRoutingAddress attribute and it must
2346 contain an RFC 822 compliant address. Some example LDAP records (in LDIF
2349 dn: uid=tom, o=example.com, c=US
2350 objectClass: inetLocalMailRecipient
2351 mailLocalAddress: tom@example.com
2352 mailRoutingAddress: thomas@mailhost.example.com
2354 This would deliver mail for tom@example.com to thomas@mailhost.example.com.
2356 dn: uid=dick, o=example.com, c=US
2357 objectClass: inetLocalMailRecipient
2358 mailLocalAddress: dick@example.com
2359 mailHost: eng.example.com
2361 This would relay mail for dick@example.com to the same address but redirect
2362 the mail to MX records listed for the host eng.example.com (unless the
2363 mailertable overrides).
2365 dn: uid=harry, o=example.com, c=US
2366 objectClass: inetLocalMailRecipient
2367 mailLocalAddress: harry@example.com
2368 mailHost: mktmail.example.com
2369 mailRoutingAddress: harry@mkt.example.com
2371 This would relay mail for harry@example.com to the MX records listed for
2372 the host mktmail.example.com using the new address harry@mkt.example.com
2373 when talking to that host.
2375 dn: uid=virtual.example.com, o=example.com, c=US
2376 objectClass: inetLocalMailRecipient
2377 mailLocalAddress: @virtual.example.com
2378 mailHost: server.example.com
2379 mailRoutingAddress: virtual@example.com
2381 This would send all mail destined for any username @virtual.example.com to
2382 the machine server.example.com's MX servers and deliver to the address
2383 virtual@example.com on that relay machine.
2386 +---------------------------------+
2387 | ANTI-SPAM CONFIGURATION CONTROL |
2388 +---------------------------------+
2390 The primary anti-spam features available in sendmail are:
2392 * Relaying is denied by default.
2393 * Better checking on sender information.
2397 Relaying (transmission of messages from a site outside your host (class
2398 {w}) to another site except yours) is denied by default. Note that this
2399 changed in sendmail 8.9; previous versions allowed relaying by default.
2400 If you really want to revert to the old behaviour, you will need to use
2401 FEATURE(`promiscuous_relay'). You can allow certain domains to relay
2402 through your server by adding their domain name or IP address to class
2403 {R} using RELAY_DOMAIN() and RELAY_DOMAIN_FILE() or via the access database
2404 (described below). Note that IPv6 addresses must be prefaced with "IPv6:".
2405 The file consists (like any other file based class) of entries listed on
2406 separate lines, e.g.,
2411 IPv6:2002:c0a8:51d2::23f4
2415 Notice: the last entry allows relaying for connections via a UNIX
2416 socket to the MTA/MSP. This might be necessary if your configuration
2417 doesn't allow relaying by other means in that case, e.g., by having
2418 localhost.$m in class {R} (make sure $m is not just a top level
2423 FEATURE(`relay_entire_domain')
2425 then any host in any of your local domains (that is, class {m})
2426 will be relayed (that is, you will accept mail either to or from any
2427 host in your domain).
2429 You can also allow relaying based on the MX records of the host
2430 portion of an incoming recipient address by using
2432 FEATURE(`relay_based_on_MX')
2434 For example, if your server receives a recipient of user@domain.com
2435 and domain.com lists your server in its MX records, the mail will be
2436 accepted for relay to domain.com. This feature may cause problems
2437 if MX lookups for the recipient domain are slow or time out. In that
2438 case, mail will be temporarily rejected. It is usually better to
2439 maintain a list of hosts/domains for which the server acts as relay.
2440 Note also that this feature will stop spammers from using your host
2441 to relay spam but it will not stop outsiders from using your server
2442 as a relay for their site (that is, they set up an MX record pointing
2443 to your mail server, and you will relay mail addressed to them
2444 without any prior arrangement). Along the same lines,
2446 FEATURE(`relay_local_from')
2448 will allow relaying if the sender specifies a return path (i.e.
2449 MAIL FROM:<user@domain>) domain which is a local domain. This is a
2450 dangerous feature as it will allow spammers to spam using your mail
2451 server by simply specifying a return address of user@your.domain.com.
2452 It should not be used unless absolutely necessary.
2453 A slightly better solution is
2455 FEATURE(`relay_mail_from')
2457 which allows relaying if the mail sender is listed as RELAY in the
2458 access map. If an optional argument `domain' (this is the literal
2459 word `domain', not a placeholder) is given, the domain portion of
2460 the mail sender is also checked to allowing relaying. This option
2461 only works together with the tag From: for the LHS of the access
2462 map entries. This feature allows spammers to abuse your mail server
2463 by specifying a return address that you enabled in your access file.
2464 This may be harder to figure out for spammers, but it should not
2465 be used unless necessary. Instead use SMTP AUTH or STARTTLS to
2466 allow relaying for roaming users.
2469 If source routing is used in the recipient address (e.g.,
2470 RCPT TO:<user%site.com@othersite.com>), sendmail will check
2471 user@site.com for relaying if othersite.com is an allowed relay host
2472 in either class {R}, class {m} if FEATURE(`relay_entire_domain') is used,
2473 or the access database if FEATURE(`access_db') is used. To prevent
2474 the address from being stripped down, use:
2476 FEATURE(`loose_relay_check')
2478 If you think you need to use this feature, you probably do not. This
2479 should only be used for sites which have no control over the addresses
2480 that they provide a gateway for. Use this FEATURE with caution as it
2481 can allow spammers to relay through your server if not setup properly.
2483 NOTICE: It is possible to relay mail through a system which the
2484 anti-relay rules do not prevent: the case of a system that does use
2485 FEATURE(`nouucp', `nospecial') / FEATURE(`nopercenthack', `nospecial')
2486 (system A) and relays local messages to a mail hub (e.g., via
2487 LOCAL_RELAY or LUSER_RELAY) (system B). If system B doesn't use the
2488 same feature (nouucp / nopercenthack) at all, addresses of the form
2489 <example.net!user@local.host> / <user%example.net@local.host>
2490 would be relayed to <user@example.net>.
2491 System A doesn't recognize `!' / `%' as an address separator and
2492 therefore forwards it to the mail hub which in turns relays it
2493 because it came from a trusted local host. So if a mailserver
2494 allows UUCP (bang-format) / %-hack addresses, all systems from which
2495 it allows relaying should do the same or reject those addresses.
2497 As of 8.9, sendmail will refuse mail if the MAIL FROM: parameter has
2498 an unresolvable domain (i.e., one that DNS, your local name service,
2499 or special case rules in ruleset 3 cannot locate). This also applies
2500 to addresses that use domain literals, e.g., <user@[1.2.3.4]>, if the
2501 IP address can't be mapped to a host name. If you want to continue
2502 to accept such domains, e.g., because you are inside a firewall that
2503 has only a limited view of the Internet host name space (note that you
2504 will not be able to return mail to them unless you have some "smart
2505 host" forwarder), use
2507 FEATURE(`accept_unresolvable_domains')
2509 Alternatively, you can allow specific addresses by adding them to
2510 the access map, e.g.,
2512 From:unresolvable.domain OK
2516 Notice: domains which are temporarily unresolvable are (temporarily)
2517 rejected with a 451 reply code. If those domains should be accepted
2518 (which is discouraged) then you can use
2523 sendmail will also refuse mail if the MAIL FROM: parameter is not
2524 fully qualified (i.e., contains a domain as well as a user). If you
2525 want to continue to accept such senders, use
2527 FEATURE(`accept_unqualified_senders')
2529 Setting the DaemonPortOptions modifier 'u' overrides the default behavior,
2530 i.e., unqualified addresses are accepted even without this FEATURE. If
2531 this FEATURE is not used, the DaemonPortOptions modifier 'f' can be used
2532 to enforce fully qualified domain names.
2534 An ``access'' database can be created to accept or reject mail from
2535 selected domains. For example, you may choose to reject all mail
2536 originating from known spammers. To enable such a database, use
2538 FEATURE(`access_db')
2540 Notice: the access database is applied to the envelope addresses
2541 and the connection information, not to the header.
2543 The FEATURE macro can accept as second parameter the key file
2544 definition for the database; for example
2546 FEATURE(`access_db', `hash -T<TMPF> /etc/mail/access_map')
2548 Notice: If a second argument is specified it must contain the option
2549 `-T<TMPF>' as shown above. The optional parameters may be
2551 `skip' enables SKIP as value part (see below).
2552 `lookupdotdomain' another way to enable the feature of the
2553 same name (see above).
2554 `relaytofulladdress' enable entries of the form
2555 To:user@example.com RELAY
2556 to allow relaying to just a specific
2557 e-mail address instead of an entire domain.
2559 Remember, since /etc/mail/access is a database, after creating the text
2560 file as described below, you must use makemap to create the database
2563 makemap hash /etc/mail/access < /etc/mail/access
2565 The table itself uses e-mail addresses, domain names, and network
2566 numbers as keys. Note that IPv6 addresses must be prefaced with "IPv6:".
2569 From:spammer@aol.com REJECT
2570 From:cyberspammer.com REJECT
2571 Connect:cyberspammer.com REJECT
2573 Connect:192.168.212 REJECT
2574 Connect:IPv6:2002:c0a8:02c7 RELAY
2575 Connect:IPv6:2002:c0a8:51d2::23f4 REJECT
2577 would refuse mail from spammer@aol.com, any user from cyberspammer.com
2578 (or any host within the cyberspammer.com domain), any host in the entire
2579 top level domain TLD, 192.168.212.* network, and the IPv6 address
2580 2002:c0a8:51d2::23f4. It would allow relay for the IPv6 network
2581 2002:c0a8:02c7::/48.
2583 Entries in the access map should be tagged according to their type.
2584 Three tags are available:
2586 Connect: connection information (${client_addr}, ${client_name})
2587 From: envelope sender
2588 To: envelope recipient
2590 Notice: untagged entries are deprecated.
2592 If the required item is looked up in a map, it will be tried first
2593 with the corresponding tag in front, then (as fallback to enable
2594 backward compatibility) without any tag, unless the specific feature
2595 requires a tag. For example,
2597 From:spammer@some.dom REJECT
2598 To:friend.domain RELAY
2599 Connect:friend.domain OK
2600 Connect:from.domain RELAY
2601 From:good@another.dom OK
2602 From:another.dom REJECT
2604 This would deny mails from spammer@some.dom but you could still
2605 send mail to that address even if FEATURE(`blocklist_recipients')
2606 is enabled. Your system will allow relaying to friend.domain, but
2607 not from it (unless enabled by other means). Connections from that
2608 domain will be allowed even if it ends up in one of the DNS based
2609 rejection lists. Relaying is enabled from from.domain but not to
2610 it (since relaying is based on the connection information for
2611 outgoing relaying, the tag Connect: must be used; for incoming
2612 relaying, which is based on the recipient address, To: must be
2613 used). The last two entries allow mails from good@another.dom but
2614 reject mail from all other addresses with another.dom as domain
2618 The value part of the map can contain:
2620 OK Accept mail even if other rules in the running
2621 ruleset would reject it, for example, if the domain
2622 name is unresolvable. "Accept" does not mean
2623 "relay", but at most acceptance for local
2624 recipients. That is, OK allows less than RELAY.
2625 RELAY Accept mail addressed to the indicated domain
2626 (or address if `relaytofulladdress' is set) or
2627 received from the indicated domain for relaying
2628 through your SMTP server. RELAY also serves as
2629 an implicit OK for the other checks.
2630 REJECT Reject the sender or recipient with a general
2632 DISCARD Discard the message completely using the
2633 $#discard mailer. If it is used in check_compat,
2634 it affects only the designated recipient, not
2635 the whole message as it does in all other cases.
2636 This should only be used if really necessary.
2637 SKIP This can only be used for host/domain names
2638 and IP addresses/nets. It will abort the current
2639 search for this entry without accepting or rejecting
2640 it but causing the default action.
2641 ### any text where ### is an RFC 821 compliant error code and
2642 "any text" is a message to return for the command.
2643 The entire string should be quoted to avoid
2648 Otherwise sendmail formats the text as email
2649 addresses, e.g., it may remove spaces.
2650 This type is deprecated, use one of the two
2651 ERROR: entries below instead.
2653 as above, but useful to mark error messages as such.
2654 If quotes need to be used to avoid modifications
2655 (see above), they should be placed like this:
2657 ERROR:"### any text"
2659 ERROR:D.S.N:### any text
2660 where D.S.N is an RFC 1893 compliant error code
2661 and the rest as above. If quotes need to be used
2662 to avoid modifications, they should be placed
2665 ERROR:D.S.N:"### any text"
2668 Quarantine the message using the given text as the
2669 quarantining reason.
2673 From:cyberspammer.com ERROR:"550 We don't accept mail from spammers"
2674 From:okay.cyberspammer.com OK
2675 Connect:sendmail.org RELAY
2676 To:sendmail.org RELAY
2677 Connect:128.32 RELAY
2678 Connect:128.32.2 SKIP
2679 Connect:IPv6:1:2:3:4:5:6:7 RELAY
2680 Connect:suspicious.example.com QUARANTINE:Mail from suspicious host
2681 Connect:[127.0.0.3] OK
2682 Connect:[IPv6:1:2:3:4:5:6:7:8] OK
2684 would accept mail from okay.cyberspammer.com, but would reject mail
2685 from all other hosts at cyberspammer.com with the indicated message.
2686 It would allow relaying mail from and to any hosts in the sendmail.org
2687 domain, and allow relaying from the IPv6 1:2:3:4:5:6:7:* network
2688 and from the 128.32.*.* network except for the 128.32.2.* network,
2689 which shows how SKIP is useful to exempt subnets/subdomains. The
2690 last two entries are for checks against ${client_name} if the IP
2691 address doesn't resolve to a hostname (or is considered as "may be
2692 forged"). That is, using square brackets means these are host
2693 names, not network numbers.
2695 Warning: if you change the RFC 821 compliant error code from the default
2696 value of 550, then you should probably also change the RFC 1893 compliant
2697 error code to match it. For example, if you use
2699 To:user@example.com ERROR:450 mailbox full
2701 the error returned would be "450 5.0.0 mailbox full" which is wrong.
2702 Use "ERROR:4.2.2:450 mailbox full" instead.
2704 Note, UUCP users may need to add hostname.UUCP to the access database
2709 FEATURE(`relay_hosts_only')
2711 then the above example will allow relaying for sendmail.org, but not
2712 hosts within the sendmail.org domain. Note that this will also require
2713 hosts listed in class {R} to be fully qualified host names.
2715 You can also use the access database to block sender addresses based on
2716 the username portion of the address. For example:
2718 From:FREE.STEALTH.MAILER@ ERROR:550 Spam not accepted
2720 Note that you must include the @ after the username to signify that
2721 this database entry is for checking only the username portion of the
2726 FEATURE(`blocklist_recipients')
2728 then you can add entries to the map for local users, hosts in your
2729 domains, or addresses in your domain which should not receive mail:
2731 To:badlocaluser@ ERROR:550 Mailbox disabled for badlocaluser
2732 To:host.my.TLD ERROR:550 That host does not accept mail
2733 To:user@other.my.TLD ERROR:550 Mailbox disabled for this recipient
2735 This would prevent a recipient of badlocaluser in any of the local
2736 domains (class {w}), any user at host.my.TLD, and the single address
2737 user@other.my.TLD from receiving mail. Please note: a local username
2738 must be now tagged with an @ (this is consistent with the check of
2739 the sender address, and hence it is possible to distinguish between
2740 hostnames and usernames). Enabling this feature will keep you from
2741 sending mails to all addresses that have an error message or REJECT
2742 as value part in the access map. Taking the example from above:
2744 spammer@aol.com REJECT
2745 cyberspammer.com REJECT
2747 Mail can't be sent to spammer@aol.com or anyone at cyberspammer.com.
2748 That's why tagged entries should be used.
2750 There are several DNS based blocklists which can be found by
2751 querying a search engine. These are databases of spammers
2752 maintained in DNS. To use such a database, specify
2754 FEATURE(`dnsbl', `dnsbl.example.com')
2756 This will cause sendmail to reject mail from any site listed in the
2757 DNS based blocklist. You must select a DNS based blocklist domain
2758 to check by specifying an argument to the FEATURE. The default
2761 Rejected: IP-ADDRESS listed at SERVER
2763 where IP-ADDRESS and SERVER are replaced by the appropriate
2764 information. A second argument can be used to specify a different
2765 text or action. For example,
2767 FEATURE(`dnsbl', `dnsbl.example.com', `quarantine')
2769 would quarantine the message if the client IP address is listed
2770 at `dnsbl.example.com'.
2772 By default, temporary lookup failures are ignored
2773 and hence cause the connection not to be rejected by the DNS based
2774 rejection list. This behavior can be changed by specifying a third
2775 argument, which must be either `t' or a full error message. For
2778 FEATURE(`dnsbl', `dnsbl.example.com', `',
2779 `"451 Temporary lookup failure for " $&{client_addr} " in dnsbl.example.com"')
2781 If `t' is used, the error message is:
2783 451 Temporary lookup failure of IP-ADDRESS at SERVER
2785 where IP-ADDRESS and SERVER are replaced by the appropriate
2788 This FEATURE can be included several times to query different
2789 DNS based rejection lists.
2791 Notice: to avoid checking your own local domains against those
2792 blocklists, use the access_db feature and add:
2795 Connect:127.0.0.1 RELAY
2797 to the access map, where 10.1 is your local network. You may
2798 want to use "RELAY" instead of "OK" to allow also relaying
2799 instead of just disabling the DNS lookups in the blocklists.
2802 The features described above make use of the check_relay, check_mail,
2803 and check_rcpt rulesets. Note that check_relay checks the SMTP
2804 client hostname and IP address when the connection is made to your
2805 server. It does not check if a mail message is being relayed to
2806 another server. That check is done in check_rcpt. If you wish to
2807 include your own checks, you can put your checks in the rulesets
2808 Local_check_relay, Local_check_mail, and Local_check_rcpt. For
2809 example if you wanted to block senders with all numeric usernames
2810 (i.e. 2312343@bigisp.com), you would use Local_check_mail and the
2814 Kallnumbers regex -a@MATCH ^[0-9]+$
2818 # check address against various regex checks
2819 R$* $: $>Parse0 $>3 $1
2820 R$+ < @ bigisp.com. > $* $: $(allnumbers $1 $)
2821 R@MATCH $#error $: 553 Header Error
2823 These rules are called with the original arguments of the corresponding
2824 check_* ruleset. If the local ruleset returns $#OK, no further checking
2825 is done by the features described above and the mail is accepted. If
2826 the local ruleset resolves to a mailer (such as $#error or $#discard),
2827 the appropriate action is taken. Other results starting with $# are
2828 interpreted by sendmail and may lead to unspecified behavior. Note: do
2829 NOT create a mailer with the name OK. Return values that do not start
2830 with $# are ignored, i.e., normal processing continues.
2835 By using FEATURE(`delay_checks') the rulesets check_mail and check_relay
2836 will not be called when a client connects or issues a MAIL command,
2837 respectively. Instead, those rulesets will be called by the check_rcpt
2838 ruleset; they will be skipped if a sender has been authenticated using
2839 a "trusted" mechanism, i.e., one that is defined via TRUST_AUTH_MECH().
2840 If check_mail returns an error then the RCPT TO command will be rejected
2841 with that error. If it returns some other result starting with $# then
2842 check_relay will be skipped. If the sender address (or a part of it) is
2843 listed in the access map and it has a RHS of OK or RELAY, then check_relay
2844 will be skipped. This has an interesting side effect: if your domain is
2845 my.domain and you have
2849 in the access map, then any e-mail with a sender address of
2850 <user@my.domain> will not be rejected by check_relay even though
2851 it would match the hostname or IP address. This allows spammers
2852 to get around DNS based blocklist by faking the sender address. To
2853 avoid this problem you have to use tagged entries:
2856 Connect:my.domain RELAY
2858 if you need those entries at all (class {R} may take care of them).
2860 FEATURE(`delay_checks') can take an optional argument:
2862 FEATURE(`delay_checks', `friend')
2863 enables spamfriend test
2864 FEATURE(`delay_checks', `hater')
2865 enables spamhater test
2867 If such an argument is given, the recipient will be looked up in the
2868 access map (using the tag Spam:). If the argument is `friend', then
2869 the default behavior is to apply the other rulesets and make a SPAM
2870 friend the exception. The rulesets check_mail and check_relay will be
2871 skipped only if the recipient address is found and has RHS FRIEND. If
2872 the argument is `hater', then the default behavior is to skip the rulesets
2873 check_mail and check_relay and make a SPAM hater the exception. The
2874 other two rulesets will be applied only if the recipient address is
2875 found and has RHS HATER.
2877 This allows for simple exceptions from the tests, e.g., by activating
2878 the friend option and having
2882 in the access map, mail to abuse@localdomain will get through (where
2883 "localdomain" is any domain in class {w}). It is also possible to
2884 specify a full address or an address with +detail:
2886 Spam:abuse@my.domain FRIEND
2887 Spam:me+abuse@ FRIEND
2888 Spam:spam.domain FRIEND
2890 Note: The required tag has been changed in 8.12 from To: to Spam:.
2891 This change is incompatible to previous versions. However, you can
2892 (for now) simply add the new entries to the access map, the old
2893 ones will be ignored. As soon as you removed the old entries from
2894 the access map, specify a third parameter (`n') to this feature and
2895 the backward compatibility rules will not be in the generated .cf
2901 You can also reject mail on the basis of the contents of headers.
2902 This is done by adding a ruleset call to the 'H' header definition command
2903 in sendmail.cf. For example, this can be used to check the validity of
2904 a Message-ID: header:
2907 HMessage-Id: $>CheckMessageId
2912 R$* $#error $: 553 Header Error
2914 The alternative format:
2916 HSubject: $>+CheckSubject
2918 that is, $>+ instead of $>, gives the full Subject: header including
2919 comments to the ruleset (comments in parentheses () are stripped
2922 A default ruleset for headers which don't have a specific ruleset
2923 defined for them can be given by:
2928 1. All rules act on tokens as explained in doc/op/op.{me,ps,txt}.
2929 That may cause problems with simple header checks due to the
2930 tokenization. It might be simpler to use a regex map and apply it
2932 2. There are no default rulesets coming with this distribution of
2933 sendmail. You can write your own, can search the WWW for examples,
2934 or take a look at cf/cf/knecht.mc.
2935 3. When using a default ruleset for headers, the name of the header
2936 currently being checked can be found in the $&{hdr_name} macro.
2938 After all of the headers are read, the check_eoh ruleset will be called for
2939 any final header-related checks. The ruleset is called with the number of
2940 headers and the size of all of the headers in bytes separated by $|. One
2941 example usage is to reject messages which do not have a Message-Id:
2942 header. However, the Message-Id: header is *NOT* a required header and is
2943 not a guaranteed spam indicator. This ruleset is an example and should
2944 probably not be used in production.
2948 HMessage-Id: $>CheckMessageId
2952 # Record the presence of the header
2953 R$* $: $(storage {MessageIdCheck} $@ OK $) $1
2955 R$* $#error $: 553 Header Error
2959 R$* $: < $&{MessageIdCheck} >
2960 # Clear the macro for the next message
2961 R$* $: $(storage {MessageIdCheck} $) $1
2962 # Has a Message-Id: header
2964 # Allow missing Message-Id: from local mail
2965 R$* $: < $&{client_name} >
2968 # Otherwise, reject the mail
2969 R$* $#error $: 553 Header Error
2972 +--------------------+
2973 | CONNECTION CONTROL |
2974 +--------------------+
2976 The features ratecontrol and conncontrol allow to establish connection
2977 limits per client IP address or net. These features can limit the
2978 rate of connections (connections per time unit) or the number of
2979 incoming SMTP connections, respectively. If enabled, appropriate
2980 rulesets are called at the end of check_relay, i.e., after DNS
2981 blocklists and generic access_db operations. The features require
2982 FEATURE(`access_db') to be listed earlier in the mc file.
2984 Note: FEATURE(`delay_checks') delays those connection control checks
2985 after a recipient address has been received, hence making these
2986 connection control features less useful. To run the checks as early
2987 as possible, specify the parameter `nodelay', e.g.,
2989 FEATURE(`ratecontrol', `nodelay')
2991 In that case, FEATURE(`delay_checks') has no effect on connection
2992 control (and it must be specified earlier in the mc file).
2994 An optional second argument `terminate' specifies whether the
2995 rulesets should return the error code 421 which will cause
2996 sendmail to terminate the session with that error if it is
2997 returned from check_relay, i.e., not delayed as explained in
2998 the previous paragraph. Example:
3000 FEATURE(`ratecontrol', `nodelay', `terminate')
3007 In this text, cert will be used as an abbreviation for X.509 certificate,
3008 DN (CN) is the distinguished (common) name of a cert, and CA is a
3009 certification authority, which signs (issues) certs.
3011 For STARTTLS to be offered by sendmail you need to set at least
3012 these variables (the file names and paths are just examples):
3014 define(`confCACERT_PATH', `/etc/mail/certs/')
3015 define(`confCACERT', `/etc/mail/certs/CA.cert.pem')
3016 define(`confSERVER_CERT', `/etc/mail/certs/my.cert.pem')
3017 define(`confSERVER_KEY', `/etc/mail/certs/my.key.pem')
3019 On systems which do not have the compile flag HASURANDOM set (see
3020 sendmail/README) you also must set confRAND_FILE.
3022 See doc/op/op.{me,ps,txt} for more information about these options,
3023 especially the sections ``Certificates for STARTTLS'' and ``PRNG for
3026 Macros related to STARTTLS are:
3028 ${cert_issuer} holds the DN of the CA (the cert issuer).
3029 ${cert_subject} holds the DN of the cert (called the cert subject).
3030 ${cn_issuer} holds the CN of the CA (the cert issuer).
3031 ${cn_subject} holds the CN of the cert (called the cert subject).
3032 ${tls_version} the TLS/SSL version used for the connection, e.g., TLSv1,
3033 TLSv1/SSLv3, SSLv3, SSLv2.
3034 ${cipher} the cipher used for the connection, e.g., EDH-DSS-DES-CBC3-SHA,
3035 EDH-RSA-DES-CBC-SHA, DES-CBC-MD5, DES-CBC3-SHA.
3036 ${cipher_bits} the keylength (in bits) of the symmetric encryption algorithm
3037 used for the connection.
3038 ${verify} holds the result of the verification of the presented cert.
3039 Possible values are:
3040 OK verification succeeded.
3041 NO no cert presented.
3042 NOT no cert requested.
3043 FAIL cert presented but could not be verified,
3044 e.g., the cert of the signing CA is missing.
3045 NONE STARTTLS has not been performed.
3046 TEMP temporary error occurred.
3047 PROTOCOL protocol error occurred (SMTP level).
3048 SOFTWARE STARTTLS handshake failed.
3049 ${server_name} the name of the server of the current outgoing SMTP
3051 ${server_addr} the address of the server of the current outgoing SMTP
3057 SMTP STARTTLS can allow relaying for remote SMTP clients which have
3058 successfully authenticated themselves. If the verification of the cert
3059 failed (${verify} != OK), relaying is subject to the usual rules.
3060 Otherwise the DN of the issuer is looked up in the access map using the
3061 tag CERTISSUER. If the resulting value is RELAY, relaying is allowed.
3062 If it is SUBJECT, the DN of the cert subject is looked up next in the
3063 access map using the tag CERTSUBJECT. If the value is RELAY, relaying
3066 To make things a bit more flexible (or complicated), the values for
3067 ${cert_issuer} and ${cert_subject} can be optionally modified by regular
3068 expressions defined in the m4 variables _CERT_REGEX_ISSUER_ and
3069 _CERT_REGEX_SUBJECT_, respectively. To avoid problems with those macros in
3070 rulesets and map lookups, they are modified as follows: each non-printable
3071 character and the characters '<', '>', '(', ')', '"', '+', ' ' are replaced
3072 by their HEX value with a leading '+'. For example:
3074 /C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/emailAddress=
3075 darth+cert@endmail.org
3079 /C=US/ST=California/O=endmail.org/OU=private/CN=
3080 Darth+20Mail+20+28Cert+29/emailAddress=darth+2Bcert@endmail.org
3082 (line breaks have been inserted for readability).
3084 The macros which are subject to this encoding are ${cert_subject},
3085 ${cert_issuer}, ${cn_subject}, and ${cn_issuer}.
3089 To allow relaying for everyone who can present a cert signed by
3091 /C=US/ST=California/O=endmail.org/OU=private/CN=
3092 Darth+20Mail+20+28Cert+29/emailAddress=darth+2Bcert@endmail.org
3096 CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
3097 Darth+20Mail+20+28Cert+29/emailAddress=darth+2Bcert@endmail.org RELAY
3099 To allow relaying only for a subset of machines that have a cert signed by
3101 /C=US/ST=California/O=endmail.org/OU=private/CN=
3102 Darth+20Mail+20+28Cert+29/emailAddress=darth+2Bcert@endmail.org
3106 CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
3107 Darth+20Mail+20+28Cert+29/emailAddress=darth+2Bcert@endmail.org SUBJECT
3108 CertSubject:/C=US/ST=California/O=endmail.org/OU=private/CN=
3109 DeathStar/emailAddress=deathstar@endmail.org RELAY
3111 Note: line breaks have been inserted after "CN=" for readability,
3112 each tagged entry must be one (long) line in the access map.
3114 Of course it is also possible to write a simple ruleset that allows
3115 relaying for everyone who can present a cert that can be verified, e.g.,
3122 Allowing Connections
3123 --------------------
3125 The rulesets tls_server, tls_client, and tls_rcpt are used to decide whether
3126 an SMTP connection is accepted (or should continue).
3128 tls_server is called when sendmail acts as client after a STARTTLS command
3129 (should) have been issued. The parameter is the value of ${verify}.
3131 tls_client is called when sendmail acts as server, after a STARTTLS command
3132 has been issued, and from check_mail. The parameter is the value of
3133 ${verify} and STARTTLS or MAIL, respectively.
3135 Both rulesets behave the same. If no access map is in use, the connection
3136 will be accepted unless ${verify} is SOFTWARE, in which case the connection
3137 is always aborted. For tls_server/tls_client, ${client_name}/${server_name}
3138 is looked up in the access map using the tag TLS_Srv/TLS_Clt, which is done
3139 with the ruleset LookUpDomain. If no entry is found, ${client_addr}
3140 (${server_addr}) is looked up in the access map (same tag, ruleset
3141 LookUpAddr). If this doesn't result in an entry either, just the tag is
3142 looked up in the access map (included the trailing colon). Notice:
3143 requiring that e-mail is sent to a server only encrypted, e.g., via
3145 TLS_Srv:secure.domain ENCR:112
3147 doesn't necessarily mean that e-mail sent to that domain is encrypted.
3148 If the domain has multiple MX servers, e.g.,
3150 secure.domain. IN MX 10 mail.secure.domain.
3151 secure.domain. IN MX 50 mail.other.domain.
3153 then mail to user@secure.domain may go unencrypted to mail.other.domain.
3154 tls_rcpt can be used to address this problem.
3156 tls_rcpt is called before a RCPT TO: command is sent. The parameter is the
3157 current recipient. This ruleset is only defined if FEATURE(`access_db')
3158 is selected. A recipient address user@domain is looked up in the access
3159 map in four formats: TLS_Rcpt:user@domain, TLS_Rcpt:user@, TLS_Rcpt:domain,
3160 and TLS_Rcpt:; the first match is taken.
3162 The result of the lookups is then used to call the ruleset TLS_connection,
3163 which checks the requirement specified by the RHS in the access map against
3164 the actual parameters of the current TLS connection, esp. ${verify} and
3165 ${cipher_bits}. Legal RHSs in the access map are:
3167 VERIFY verification must have succeeded
3168 VERIFY:bits verification must have succeeded and ${cipher_bits} must
3169 be greater than or equal bits.
3170 ENCR:bits ${cipher_bits} must be greater than or equal bits.
3172 The RHS can optionally be prefixed by TEMP+ or PERM+ to select a temporary
3173 or permanent error. The default is a temporary error code (403 4.7.0)
3174 unless the macro TLS_PERM_ERR is set during generation of the .cf file.
3176 If a certain level of encryption is required, then it might also be
3177 possible that this level is provided by the security layer from a SASL
3178 algorithm, e.g., DIGEST-MD5.
3180 Furthermore, there can be a list of extensions added. Such a list
3181 starts with '+' and the items are separated by '++'. Allowed
3184 CN:name name must match ${cn_subject}
3185 CN ${client_name}/${server_name} must match ${cn_subject}
3186 CS:name name must match ${cert_subject}
3187 CI:name name must match ${cert_issuer}
3188 CITag:MYTag look up MYTag:${cert_issuer} in access map; the check
3189 only succeeds if it is found with a RHS of OK.
3191 Example: e-mail sent to secure.example.com should only use an encrypted
3192 connection. E-mail received from hosts within the laptop.example.com domain
3193 should only be accepted if they have been authenticated. The host which
3194 receives e-mail for darth@endmail.org must present a cert that uses the
3195 CN smtp.endmail.org. E-mail sent to safe.example.com must be verified,
3196 have a matching CN, and must present a cert signed by a CA with one of
3199 TLS_Srv:secure.example.com ENCR:112
3200 TLS_Clt:laptop.example.com PERM+VERIFY:112
3201 TLS_Rcpt:darth@endmail.org ENCR:112+CN:smtp.endmail.org
3202 TLS_Srv:safe.example.net VERIFY+CN++CITag:MyCA
3203 MyCA:/C=US/ST=CA/O=safe/CN=example.net/ OK
3204 MyCA:/C=US/ST=CA/O=secure/CN=example.net/ OK
3207 TLS Options per Session
3208 -----------------------
3210 By default STARTTLS is used whenever possible. However, there are
3211 MTAs with STARTTLS interoperability issues. To be able to send to
3212 (or receive from) those MTAs several features are available:
3214 1) Various TLS options be be set per IP/domain.
3215 2) STARTTLS can be turned off for specific IP addresses/domains.
3217 About 1): the rulesets tls_srv_features and tls_clt_features can
3218 be used to return a (semicolon separated) list of TLS related
3221 - Options: compare {Server,Client}SSLOptions.
3222 - CipherList: same as the global option.
3223 - CertFile, KeyFile: {Server,Client}{Cert,Key}File
3224 - Flags: see doc/op/op.me for details.
3226 If FEATURE(`tls_session_features') is used, then default rulesets
3227 are activated which look up entries in the access map with the tags
3228 TLS_Srv_features and TLS_Clt_features, respectively.
3229 For example, these entries:
3231 TLS_Srv_features:10.0.2.4 CipherList=MEDIUM+aRSA;
3232 TLS_Clt_features:10.1.0.1 Options=SSL_OP_NO_TLSv1_2; CipherList=ALL:-EXPORT
3234 specify a cipherlist with MEDIUM strength ciphers that use RSA
3235 certificates only for the client with the IP address 10.0.2.4,
3236 and turn off TLSv1.2 when connecting to the server with the IP
3237 address 10.1.0.1 as well as setting a specific cipherlist.
3238 If FEATURE(`tls_session_features') is not used the user can provide
3239 their own rulesets which must return the appropriate data.
3240 If the rulesets are not defined or do not return a value, the
3241 default TLS options are not modified.
3243 About 2): the ruleset try_tls (srv_features) can be used together
3244 with the access map. Entries for the access map must be tagged
3245 with Try_TLS (Srv_Features) and refer to the hostname or IP address
3246 of the connecting system. A default case can be specified by using
3247 just the tag. For example, the following entries in the access map:
3249 Try_TLS:broken.server NO
3250 Srv_Features:my.domain v
3253 will turn off STARTTLS when sending to broken.server (or any host
3254 in that domain), and request a client certificate during the TLS
3255 handshake only for hosts in my.domain. The valid entries on the RHS
3256 for Srv_Features are listed in the Sendmail Installation and
3263 The Received: header reveals whether STARTTLS has been used. It contains an
3266 (version=${tls_version} cipher=${cipher} bits=${cipher_bits} verify=${verify})
3269 +---------------------+
3270 | SMTP AUTHENTICATION |
3271 +---------------------+
3273 The macros ${auth_authen}, ${auth_author}, and ${auth_type} can be
3274 used in anti-relay rulesets to allow relaying for those users that
3275 authenticated themselves. A very simple example is:
3278 R$* $: $&{auth_type}
3281 which checks whether a user has successfully authenticated using
3282 any available mechanism. Depending on the setup of the Cyrus SASL
3283 library, more sophisticated rulesets might be required, e.g.,
3286 R$* $: $&{auth_type} $| $&{auth_authen}
3287 RDIGEST-MD5 $| $+@$=w $# OK
3289 to allow relaying for users that authenticated using DIGEST-MD5
3290 and have an identity in the local domains.
3292 The ruleset trust_auth is used to determine whether a given AUTH=
3293 parameter (that is passed to this ruleset) should be trusted. This
3294 ruleset may make use of the other ${auth_*} macros. Only if the
3295 ruleset resolves to the error mailer, the AUTH= parameter is not
3296 trusted. A user supplied ruleset Local_trust_auth can be written
3297 to modify the default behavior, which only trust the AUTH=
3298 parameter if it is identical to the authenticated user.
3300 Per default, relaying is allowed for any user who authenticated
3301 via a "trusted" mechanism, i.e., one that is defined via
3302 TRUST_AUTH_MECH(`list of mechanisms')
3304 TRUST_AUTH_MECH(`KERBEROS_V4 DIGEST-MD5')
3306 If the selected mechanism provides a security layer the number of
3307 bits used for the key of the symmetric cipher is stored in the
3310 Providing SMTP AUTH Data when sendmail acts as Client
3311 -----------------------------------------------------
3313 If sendmail acts as client, it needs some information how to
3314 authenticate against another MTA. This information can be provided
3315 by the ruleset authinfo or by the option DefaultAuthInfo. The
3316 authinfo ruleset looks up {server_name} using the tag AuthInfo: in
3317 the access map. If no entry is found, {server_addr} is looked up
3318 in the same way and finally just the tag AuthInfo: to provide
3319 default values. Note: searches for domain parts or IP nets are
3320 only performed if the access map is used; if the authinfo feature
3321 is used then only up to three lookups are performed (two exact
3322 matches, one default).
3324 Note: If your daemon does client authentication when sending, and
3325 if it uses either PLAIN or LOGIN authentication, then you *must*
3326 prevent ordinary users from seeing verbose output. Do NOT install
3327 sendmail set-user-ID. Use PrivacyOptions to turn off verbose output
3328 ("goaway" works for this).
3330 Notice: the default configuration file causes the option DefaultAuthInfo
3331 to fail since the ruleset authinfo is in the .cf file. If you really
3332 want to use DefaultAuthInfo (it is deprecated) then you have to
3335 The RHS for an AuthInfo: entry in the access map should consists of a
3336 list of tokens, each of which has the form: "TDstring" (including
3337 the quotes). T is a tag which describes the item, D is a delimiter,
3338 either ':' for simple text or '=' for a base64 encoded string.
3339 Valid values for the tag are:
3341 U user (authorization) id
3345 M list of mechanisms delimited by spaces
3347 Example entries are:
3349 AuthInfo:other.dom "U:user" "I:user" "P:secret" "R:other.dom" "M:DIGEST-MD5"
3350 AuthInfo:host.more.dom "U:user" "P=c2VjcmV0"
3352 User id or authentication id must exist as well as the password. All
3353 other entries have default values. If one of user or authentication
3354 id is missing, the existing value is used for the missing item.
3355 If "R:" is not specified, realm defaults to $j. The list of mechanisms
3356 defaults to those specified by AuthMechanisms.
3358 Since this map contains sensitive information, either the access
3359 map must be unreadable by everyone but root (or the trusted user)
3360 or FEATURE(`authinfo') must be used which provides a separate map.
3361 Notice: It is not checked whether the map is actually
3362 group/world-unreadable, this is left to the user.
3364 +--------------------------------+
3365 | ADDING NEW MAILERS OR RULESETS |
3366 +--------------------------------+
3368 Sometimes you may need to add entirely new mailers or rulesets. They
3369 should be introduced with the constructs MAILER_DEFINITIONS and
3370 LOCAL_RULESETS respectively. For example:
3380 Local additions for the rulesets srv_features, try_tls, tls_rcpt,
3381 tls_client, and tls_server can be made using LOCAL_SRV_FEATURES,
3382 LOCAL_TRY_TLS, LOCAL_TLS_RCPT, LOCAL_TLS_CLIENT, and LOCAL_TLS_SERVER,
3383 respectively. For example, to add a local ruleset that decides
3384 whether to try STARTTLS in a sendmail client, use:
3389 Note: you don't need to add a name for the ruleset, it is implicitly
3390 defined by using the appropriate macro.
3393 +-------------------------+
3394 | ADDING NEW MAIL FILTERS |
3395 +-------------------------+
3397 Sendmail supports mail filters to filter incoming SMTP messages according
3398 to the "Sendmail Mail Filter API" documentation. These filters can be
3399 configured in your mc file using the two commands:
3401 MAIL_FILTER(`name', `equates')
3402 INPUT_MAIL_FILTER(`name', `equates')
3404 The first command, MAIL_FILTER(), simply defines a filter with the given
3405 name and equates. For example:
3407 MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3409 This creates the equivalent sendmail.cf entry:
3411 Xarchive, S=local:/var/run/archivesock, F=R
3413 The INPUT_MAIL_FILTER() command performs the same actions as MAIL_FILTER
3414 but also populates the m4 variable `confINPUT_MAIL_FILTERS' with the name
3415 of the filter such that the filter will actually be called by sendmail.
3417 For example, the two commands:
3419 INPUT_MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3420 INPUT_MAIL_FILTER(`spamcheck', `S=inet:2525@localhost, F=T')
3422 are equivalent to the three commands:
3424 MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3425 MAIL_FILTER(`spamcheck', `S=inet:2525@localhost, F=T')
3426 define(`confINPUT_MAIL_FILTERS', `archive, spamcheck')
3428 In general, INPUT_MAIL_FILTER() should be used unless you need to define
3429 more filters than you want to use for `confINPUT_MAIL_FILTERS'.
3431 Note that setting `confINPUT_MAIL_FILTERS' after any INPUT_MAIL_FILTER()
3432 commands will clear the list created by the prior INPUT_MAIL_FILTER()
3436 +-------------------------+
3437 | QUEUE GROUP DEFINITIONS |
3438 +-------------------------+
3440 In addition to the queue directory (which is the default queue group
3441 called "mqueue"), sendmail can deal with multiple queue groups, which
3442 are collections of queue directories with the same behaviour. Queue
3443 groups can be defined using the command:
3445 QUEUE_GROUP(`name', `equates')
3447 For details about queue groups, please see doc/op/op.{me,ps,txt}.
3449 +-------------------------------+
3450 | NON-SMTP BASED CONFIGURATIONS |
3451 +-------------------------------+
3453 These configuration files are designed primarily for use by
3454 SMTP-based sites. They may not be well tuned for UUCP-only or
3455 UUCP-primarily nodes (the latter is defined as a small local net
3456 connected to the rest of the world via UUCP). However, there is
3457 one hook to handle some special cases.
3459 You can define a ``smart host'' that understands a richer address syntax
3462 define(`SMART_HOST', `mailer:hostname')
3464 In this case, the ``mailer:'' defaults to "relay". Any messages that
3465 can't be handled using the usual UUCP rules are passed to this host.
3467 If you are on a local SMTP-based net that connects to the outside
3468 world via UUCP, you can use LOCAL_NET_CONFIG to add appropriate rules.
3471 define(`SMART_HOST', `uucp-new:uunet')
3473 R$* < @ $* .$m. > $* $#smtp $@ $2.$m. $: $1 < @ $2.$m. > $3
3475 This will cause all names that end in your domain name ($m) to be sent
3476 via SMTP; anything else will be sent via uucp-new (smart UUCP) to uunet.
3477 If you have FEATURE(`nocanonify'), you may need to omit the dots after
3478 the $m. If you are running a local DNS inside your domain which is
3479 not otherwise connected to the outside world, you probably want to
3482 define(`SMART_HOST', `smtp:fire.wall.com')
3484 R$* < @ $* . > $* $#smtp $@ $2. $: $1 < @ $2. > $3
3486 That is, send directly only to things you found in your DNS lookup;
3487 anything else goes through SMART_HOST.
3489 You may need to turn off the anti-spam rules in order to accept
3490 UUCP mail with FEATURE(`promiscuous_relay') and
3491 FEATURE(`accept_unresolvable_domains').
3498 Normally, the $j macro is automatically defined to be your fully
3499 qualified domain name (FQDN). Sendmail does this by getting your
3500 host name using gethostname and then calling gethostbyname on the
3501 result. For example, in some environments gethostname returns
3502 only the root of the host name (such as "foo"); gethostbyname is
3503 supposed to return the FQDN ("foo.bar.com"). In some (fairly rare)
3504 cases, gethostbyname may fail to return the FQDN. In this case
3505 you MUST define confDOMAIN_NAME to be your fully qualified domain
3506 name. This is usually done using:
3509 define(`confDOMAIN_NAME', `$w.$m')dnl
3512 +-----------------------------------+
3513 | ACCEPTING MAIL FOR MULTIPLE NAMES |
3514 +-----------------------------------+
3516 If your host is known by several different names, you need to augment
3517 class {w}. This is a list of names by which your host is known, and
3518 anything sent to an address using a host name in this list will be
3519 treated as local mail. You can do this in two ways: either create the
3520 file /etc/mail/local-host-names containing a list of your aliases (one per
3521 line), and use ``FEATURE(`use_cw_file')'' in the .mc file, or add
3522 ``LOCAL_DOMAIN(`alias.host.name')''. Be sure you use the fully-qualified
3523 name of the host, rather than a short name.
3525 If you want to have different address in different domains, take
3526 a look at the virtusertable feature, which is also explained at
3527 http://www.sendmail.org/virtual-hosting.html
3530 +--------------------+
3531 | USING MAILERTABLES |
3532 +--------------------+
3534 To use FEATURE(`mailertable'), you will have to create an external
3535 database containing the routing information for various domains.
3536 For example, a mailertable file in text format might be:
3538 .my.domain xnet:%1.my.domain
3539 uuhost1.my.domain uucp-new:uuhost1
3540 .bitnet smtp:relay.bit.net
3542 This should normally be stored in /etc/mail/mailertable. The actual
3543 database version of the mailertable is built using:
3545 makemap hash /etc/mail/mailertable < /etc/mail/mailertable
3547 The semantics are simple. Any LHS entry that does not begin with
3548 a dot matches the full host name indicated. LHS entries beginning
3549 with a dot match anything ending with that domain name (including
3550 the leading dot) -- that is, they can be thought of as having a
3551 leading ".+" regular expression pattern for a non-empty sequence of
3552 characters. Matching is done in order of most-to-least qualified
3553 -- for example, even though ".my.domain" is listed first in the
3554 above example, an entry of "uuhost1.my.domain" will match the second
3555 entry since it is more explicit. Note: e-mail to "user@my.domain"
3556 does not match any entry in the above table. You need to have
3559 my.domain esmtp:host.my.domain
3561 The RHS should always be a "mailer:host" pair. The mailer is the
3562 configuration name of a mailer (that is, an M line in the
3563 sendmail.cf file). The "host" will be the hostname passed to
3564 that mailer. In domain-based matches (that is, those with leading
3565 dots) the "%1" may be used to interpolate the wildcarded part of
3566 the host name. For example, the first line above sends everything
3567 addressed to "anything.my.domain" to that same host name, but using
3568 the (presumably experimental) xnet mailer.
3570 In some cases you may want to temporarily turn off MX records,
3571 particularly on gateways. For example, you may want to MX
3572 everything in a domain to one machine that then forwards it
3573 directly. To do this, you might use the DNS configuration:
3575 *.domain. IN MX 0 relay.machine
3577 and on relay.machine use the mailertable:
3579 .domain smtp:[gateway.domain]
3581 The [square brackets] turn off MX records for this host only.
3582 If you didn't do this, the mailertable would use the MX record
3583 again, which would give you an MX loop. Note that the use of
3584 wildcard MX records is almost always a bad idea. Please avoid
3585 using them if possible.
3588 +--------------------------------+
3589 | USING USERDB TO MAP FULL NAMES |
3590 +--------------------------------+
3592 The user database was not originally intended for mapping full names
3593 to login names (e.g., Eric.Allman => eric), but some people are using
3594 it that way. (it is recommended that you set up aliases for this
3595 purpose instead -- since you can specify multiple alias files, this
3596 is fairly easy.) The intent was to locate the default maildrop at
3597 a site, but allow you to override this by sending to a specific host.
3599 If you decide to set up the user database in this fashion, it is
3600 imperative that you not use FEATURE(`stickyhost') -- otherwise,
3601 e-mail sent to Full.Name@local.host.name will be rejected.
3603 To build the internal form of the user database, use:
3605 makemap btree /etc/mail/userdb < /etc/mail/userdb.txt
3607 As a general rule, it is an extremely bad idea to using full names
3608 as e-mail addresses, since they are not in any sense unique. For
3609 example, the UNIX software-development community has at least two
3610 well-known Peter Deutsches, and at one time Bell Labs had two
3611 Stephen R. Bournes with offices along the same hallway. Which one
3612 will be forced to suffer the indignity of being Stephen_R_Bourne_2?
3613 The less famous of the two, or the one that was hired later?
3615 Finger should handle full names (and be fuzzy). Mail should use
3616 handles, and not be fuzzy.
3619 +--------------------------------+
3620 | MISCELLANEOUS SPECIAL FEATURES |
3621 +--------------------------------+
3624 Sometimes it is convenient to merge configuration on a
3625 centralized mail machine, for example, to forward all
3626 root mail to a mail server. In this case it might be
3627 useful to be able to treat the root addresses as a class
3628 of addresses with subtle differences. You can do this
3629 using plussed users. For example, a client might include
3632 root: root+client1@server
3634 On the server, this will match an alias for "root+client1".
3635 If that is not found, the alias "root+*" will be tried,
3643 A lot of sendmail security comes down to you. Sendmail 8 is much
3644 more careful about checking for security problems than previous
3645 versions, but there are some things that you still need to watch
3648 * Make sure the aliases file is not writable except by trusted
3649 system personnel. This includes both the text and database
3652 * Make sure that other files that sendmail reads, such as the
3653 mailertable, are only writable by trusted system personnel.
3655 * The queue directory should not be world writable PARTICULARLY
3656 if your system allows "file giveaways" (that is, if a non-root
3657 user can chown any file they own to any other user).
3659 * If your system allows file giveaways, DO NOT create a publicly
3660 writable directory for forward files. This will allow anyone
3661 to steal anyone else's e-mail. Instead, create a script that
3662 copies the .forward file from users' home directories once a
3663 night (if you want the non-NFS-mounted forward directory).
3665 * If your system allows file giveaways, you'll find that
3666 sendmail is much less trusting of :include: files -- in
3667 particular, you'll have to have /SENDMAIL/ANY/SHELL/ in
3668 /etc/shells before they will be trusted (that is, before
3669 files and programs listed in them will be honored).
3671 In general, file giveaways are a mistake -- if you can turn them
3675 +--------------------------------+
3676 | TWEAKING CONFIGURATION OPTIONS |
3677 +--------------------------------+
3679 There are a large number of configuration options that don't normally
3680 need to be changed. However, if you feel you need to tweak them,
3681 you can define the following M4 variables. Note that some of these
3682 variables require formats that are defined in RFC 2821 or RFC 2822.
3683 Before changing them you need to make sure you do not violate those
3684 (and other relevant) RFCs.
3686 This list is shown in four columns: the name you define, the default
3687 value for that definition, the option or macro that is affected
3688 (either Ox for an option or Dx for a macro), and a brief description.
3689 Greater detail of the semantics can be found in the Installation
3690 and Operations Guide.
3692 Some options are likely to be deprecated in future versions -- that is,
3693 the option is only included to provide back-compatibility. These are
3696 Remember that these options are M4 variables, and hence may need to
3697 be quoted. In particular, arguments with commas will usually have to
3698 be ``double quoted, like this phrase'' to avoid having the comma
3699 confuse things. This is common for alias file definitions and for
3702 M4 Variable Name Configuration [Default] & Description
3703 ================ ============= =======================
3704 confMAILER_NAME $n macro [MAILER-DAEMON] The sender name used
3705 for internally generated outgoing
3707 confDOMAIN_NAME $j macro If defined, sets $j. This should
3708 only be done if your system cannot
3709 determine your local domain name,
3710 and then it should be set to
3711 $w.Foo.COM, where Foo.COM is your
3713 confCF_VERSION $Z macro If defined, this is appended to the
3714 configuration version name.
3715 confLDAP_CLUSTER ${sendmailMTACluster} macro
3716 If defined, this is the LDAP
3717 cluster to use for LDAP searches
3718 as described above in ``USING LDAP
3719 FOR ALIASES, MAPS, AND CLASSES''.
3720 confFROM_HEADER From: [$?x$x <$g>$|$g$.] The format of an
3721 internally generated From: address.
3722 confRECEIVED_HEADER Received:
3723 [$?sfrom $s $.$?_($?s$|from $.$_)
3724 $.$?{auth_type}(authenticated)
3725 $.by $j ($v/$Z)$?r with $r$. id $i$?u
3728 The format of the Received: header
3729 in messages passed through this host.
3730 It is unwise to try to change this.
3731 confMESSAGEID_HEADER Message-Id: [<$t.$i@$j>] The format of an
3732 internally generated Message-Id:
3734 confCW_FILE Fw class [/etc/mail/local-host-names] Name
3735 of file used to get the local
3736 additions to class {w} (local host
3738 confCT_FILE Ft class [/etc/mail/trusted-users] Name of
3739 file used to get the local additions
3740 to class {t} (trusted users).
3741 confCR_FILE FR class [/etc/mail/relay-domains] Name of
3742 file used to get the local additions
3743 to class {R} (hosts allowed to relay).
3744 confTRUSTED_USERS Ct class [no default] Names of users to add to
3745 the list of trusted users. This list
3746 always includes root, uucp, and daemon.
3747 See also FEATURE(`use_ct_file').
3748 confTRUSTED_USER TrustedUser [no default] Trusted user for file
3749 ownership and starting the daemon.
3750 Not to be confused with
3751 confTRUSTED_USERS (see above).
3752 confSMTP_MAILER - [esmtp] The mailer name used when
3753 SMTP connectivity is required.
3754 One of "smtp", "smtp8",
3755 "esmtp", or "dsmtp".
3756 confUUCP_MAILER - [uucp-old] The mailer to be used by
3757 default for bang-format recipient
3758 addresses. See also discussion of
3759 class {U}, class {Y}, and class {Z}
3760 in the MAILER(`uucp') section.
3761 confLOCAL_MAILER - [local] The mailer name used when
3762 local connectivity is required.
3763 Almost always "local".
3764 confRELAY_MAILER - [relay] The default mailer name used
3765 for relaying any mail (e.g., to a
3766 BITNET_RELAY, a SMART_HOST, or
3767 whatever). This can reasonably be
3768 "uucp-new" if you are on a
3769 UUCP-connected site.
3770 confSEVEN_BIT_INPUT SevenBitInput [False] Force input to seven bits?
3771 confEIGHT_BIT_HANDLING EightBitMode [pass8] 8-bit data handling
3772 confALIAS_WAIT AliasWait [10m] Time to wait for alias file
3773 rebuild until you get bored and
3774 decide that the apparently pending
3776 confMIN_FREE_BLOCKS MinFreeBlocks [100] Minimum number of free blocks on
3777 queue filesystem to accept SMTP mail.
3778 (Prior to 8.7 this was minfree/maxsize,
3779 where minfree was the number of free
3780 blocks and maxsize was the maximum
3781 message size. Use confMAX_MESSAGE_SIZE
3782 for the second value now.)
3783 confMAX_MESSAGE_SIZE MaxMessageSize [infinite] The maximum size of messages
3784 that will be accepted (in bytes).
3785 confBLANK_SUB BlankSub [.] Blank (space) substitution
3787 confCON_EXPENSIVE HoldExpensive [False] Avoid connecting immediately
3788 to mailers marked expensive.
3789 confCHECKPOINT_INTERVAL CheckpointInterval
3790 [10] Checkpoint queue files every N
3792 confDELIVERY_MODE DeliveryMode [background] Default delivery mode.
3793 confERROR_MODE ErrorMode [print] Error message mode.
3794 confERROR_MESSAGE ErrorHeader [undefined] Error message header/file.
3795 confSAVE_FROM_LINES SaveFromLine Save extra leading From_ lines.
3796 confTEMP_FILE_MODE TempFileMode [0600] Temporary file mode.
3797 confMATCH_GECOS MatchGECOS [False] Match GECOS field.
3798 confMAX_HOP MaxHopCount [25] Maximum hop count.
3799 confIGNORE_DOTS* IgnoreDots [False; always False in -bs or -bd
3800 mode] Ignore dot as terminator for
3802 confBIND_OPTS ResolverOptions [undefined] Default options for DNS
3804 confMIME_FORMAT_ERRORS* SendMimeErrors [True] Send error messages as MIME-
3805 encapsulated messages per RFC 1344.
3806 confFORWARD_PATH ForwardPath [$z/.forward.$w:$z/.forward]
3807 The colon-separated list of places to
3808 search for .forward files. N.B.: see
3809 the Security Notes section.
3810 confMCI_CACHE_SIZE ConnectionCacheSize
3811 [2] Size of open connection cache.
3812 confMCI_CACHE_TIMEOUT ConnectionCacheTimeout
3813 [5m] Open connection cache timeout.
3814 confHOST_STATUS_DIRECTORY HostStatusDirectory
3815 [undefined] If set, host status is kept
3816 on disk between sendmail runs in the
3817 named directory tree. This need not be
3818 a full pathname, in which case it is
3819 interpreted relative to the queue
3821 confSINGLE_THREAD_DELIVERY SingleThreadDelivery
3822 [False] If this option and the
3823 HostStatusDirectory option are both
3824 set, single thread deliveries to other
3825 hosts. That is, don't allow any two
3826 sendmails on this host to connect
3827 simultaneously to any other single
3828 host. This can slow down delivery in
3829 some cases, in particular since a
3830 cached but otherwise idle connection
3831 to a host will prevent other sendmails
3832 from connecting to the other host.
3833 confUSE_COMPRESSED_IPV6_ADDRESSES
3834 UseCompressedIPv6Addresses
3835 [undefined] If set, use the compressed
3836 form of IPv6 addresses, such as
3837 IPV6:::1, instead of the uncompressed
3838 form, such as IPv6:0:0:0:0:0:0:0:1.
3839 confUSE_ERRORS_TO* UseErrorsTo [False] Use the Errors-To: header to
3840 deliver error messages. This should
3841 not be necessary because of general
3842 acceptance of the envelope/header
3844 confLOG_LEVEL LogLevel [9] Log level.
3845 confME_TOO MeToo [True] Include sender in group
3846 expansions. This option is
3847 deprecated and will be removed from
3849 confCHECK_ALIASES CheckAliases [False] Check RHS of aliases when
3850 running newaliases. Since this does
3851 DNS lookups on every address, it can
3852 slow down the alias rebuild process
3853 considerably on large alias files.
3854 confOLD_STYLE_HEADERS* OldStyleHeaders [True] Assume that headers without
3855 special chars are old style.
3856 confPRIVACY_FLAGS PrivacyOptions [authwarnings] Privacy flags.
3857 confCOPY_ERRORS_TO PostmasterCopy [undefined] Address for additional
3858 copies of all error messages.
3859 confQUEUE_FACTOR QueueFactor [600000] Slope of queue-only function.
3860 confQUEUE_FILE_MODE QueueFileMode [undefined] Default permissions for
3861 queue files (octal). If not set,
3862 sendmail uses 0600 unless its real
3863 and effective uid are different in
3864 which case it uses 0644.
3865 confDONT_PRUNE_ROUTES DontPruneRoutes [False] Don't prune down route-addr
3866 syntax addresses to the minimum
3868 confSAFE_QUEUE* SuperSafe [True] Commit all messages to disk
3870 confTO_INITIAL Timeout.initial [5m] The timeout waiting for a response
3871 on the initial connect.
3872 confTO_CONNECT Timeout.connect [0] The timeout waiting for an initial
3873 connect() to complete. This can only
3874 shorten connection timeouts; the kernel
3875 silently enforces an absolute maximum
3876 (which varies depending on the system).
3877 confTO_ICONNECT Timeout.iconnect
3878 [undefined] Like Timeout.connect, but
3879 applies only to the very first attempt
3880 to connect to a host in a message.
3881 This allows a single very fast pass
3882 followed by more careful delivery
3883 attempts in the future.
3884 confTO_ACONNECT Timeout.aconnect
3885 [0] The overall timeout waiting for
3886 all connection for a single delivery
3887 attempt to succeed. If 0, no overall
3889 confTO_HELO Timeout.helo [5m] The timeout waiting for a response
3890 to a HELO or EHLO command.
3891 confTO_MAIL Timeout.mail [10m] The timeout waiting for a
3892 response to the MAIL command.
3893 confTO_RCPT Timeout.rcpt [1h] The timeout waiting for a response
3894 to the RCPT command.
3895 confTO_DATAINIT Timeout.datainit
3896 [5m] The timeout waiting for a 354
3897 response from the DATA command.
3898 confTO_DATABLOCK Timeout.datablock
3899 [1h] The timeout waiting for a block
3901 confTO_DATAFINAL Timeout.datafinal
3902 [1h] The timeout waiting for a response
3903 to the final "." that terminates a
3905 confTO_RSET Timeout.rset [5m] The timeout waiting for a response
3906 to the RSET command.
3907 confTO_QUIT Timeout.quit [2m] The timeout waiting for a response
3908 to the QUIT command.
3909 confTO_MISC Timeout.misc [2m] The timeout waiting for a response
3910 to other SMTP commands.
3911 confTO_COMMAND Timeout.command [1h] In server SMTP, the timeout
3912 waiting for a command to be issued.
3913 confTO_IDENT Timeout.ident [5s] The timeout waiting for a
3914 response to an IDENT query.
3915 confTO_FILEOPEN Timeout.fileopen
3916 [60s] The timeout waiting for a file
3917 (e.g., :include: file) to be opened.
3918 confTO_LHLO Timeout.lhlo [2m] The timeout waiting for a response
3919 to an LMTP LHLO command.
3920 confTO_AUTH Timeout.auth [10m] The timeout waiting for a
3921 response in an AUTH dialogue.
3922 confTO_STARTTLS Timeout.starttls
3923 [1h] The timeout waiting for a
3924 response to an SMTP STARTTLS command.
3925 confTO_CONTROL Timeout.control
3926 [2m] The timeout for a complete
3927 control socket transaction to complete.
3928 confTO_QUEUERETURN Timeout.queuereturn
3929 [5d] The timeout before a message is
3930 returned as undeliverable.
3931 confTO_QUEUERETURN_NORMAL
3932 Timeout.queuereturn.normal
3933 [undefined] As above, for normal
3935 confTO_QUEUERETURN_URGENT
3936 Timeout.queuereturn.urgent
3937 [undefined] As above, for urgent
3939 confTO_QUEUERETURN_NONURGENT
3940 Timeout.queuereturn.non-urgent
3941 [undefined] As above, for non-urgent
3942 (low) priority messages.
3943 confTO_QUEUERETURN_DSN
3944 Timeout.queuereturn.dsn
3945 [undefined] As above, for delivery
3946 status notification messages.
3947 confTO_QUEUEWARN Timeout.queuewarn
3948 [4h] The timeout before a warning
3949 message is sent to the sender telling
3950 them that the message has been
3952 confTO_QUEUEWARN_NORMAL Timeout.queuewarn.normal
3953 [undefined] As above, for normal
3955 confTO_QUEUEWARN_URGENT Timeout.queuewarn.urgent
3956 [undefined] As above, for urgent
3958 confTO_QUEUEWARN_NONURGENT
3959 Timeout.queuewarn.non-urgent
3960 [undefined] As above, for non-urgent
3961 (low) priority messages.
3962 confTO_QUEUEWARN_DSN
3963 Timeout.queuewarn.dsn
3964 [undefined] As above, for delivery
3965 status notification messages.
3966 confTO_HOSTSTATUS Timeout.hoststatus
3967 [30m] How long information about host
3968 statuses will be maintained before it
3969 is considered stale and the host should
3970 be retried. This applies both within
3971 a single queue run and to persistent
3972 information (see below).
3973 confTO_RESOLVER_RETRANS Timeout.resolver.retrans
3974 [varies] Sets the resolver's
3975 retransmission time interval (in
3977 Timeout.resolver.retrans.first and
3978 Timeout.resolver.retrans.normal.
3979 confTO_RESOLVER_RETRANS_FIRST Timeout.resolver.retrans.first
3980 [varies] Sets the resolver's
3981 retransmission time interval (in
3982 seconds) for the first attempt to
3984 confTO_RESOLVER_RETRANS_NORMAL Timeout.resolver.retrans.normal
3985 [varies] Sets the resolver's
3986 retransmission time interval (in
3987 seconds) for all resolver lookups
3988 except the first delivery attempt.
3989 confTO_RESOLVER_RETRY Timeout.resolver.retry
3990 [varies] Sets the number of times
3991 to retransmit a resolver query.
3993 Timeout.resolver.retry.first and
3994 Timeout.resolver.retry.normal.
3995 confTO_RESOLVER_RETRY_FIRST Timeout.resolver.retry.first
3996 [varies] Sets the number of times
3997 to retransmit a resolver query for
3998 the first attempt to deliver a
4000 confTO_RESOLVER_RETRY_NORMAL Timeout.resolver.retry.normal
4001 [varies] Sets the number of times
4002 to retransmit a resolver query for
4003 all resolver lookups except the
4004 first delivery attempt.
4005 confTIME_ZONE TimeZoneSpec [USE_SYSTEM] Time zone info -- can be
4006 USE_SYSTEM to use the system's idea,
4007 USE_TZ to use the user's TZ envariable,
4008 or something else to force that value.
4009 confDEF_USER_ID DefaultUser [1:1] Default user id.
4010 confUSERDB_SPEC UserDatabaseSpec
4011 [undefined] User database
4013 confFALLBACK_MX FallbackMXhost [undefined] Fallback MX host.
4014 confFALLBACK_SMARTHOST FallbackSmartHost
4015 [undefined] Fallback smart host.
4016 confTLS_FALLBACK_TO_CLEAR TLSFallbacktoClear
4017 [undefined] If set, immediately try
4018 a connection again without STARTTLS
4019 after a TLS handshake failure.
4020 confTRY_NULL_MX_LIST TryNullMXList [False] If this host is the best MX
4021 for a host and other arrangements
4022 haven't been made, try connecting
4023 to the host directly; normally this
4024 would be a config error.
4025 confQUEUE_LA QueueLA [varies] Load average at which
4026 queue-only function kicks in.
4027 Default values is (8 * numproc)
4028 where numproc is the number of
4029 processors online (if that can be
4031 confREFUSE_LA RefuseLA [varies] Load average at which
4032 incoming SMTP connections are
4033 refused. Default values is (12 *
4034 numproc) where numproc is the
4035 number of processors online (if
4036 that can be determined).
4037 confREJECT_LOG_INTERVAL RejectLogInterval [3h] Log interval when
4038 refusing connections for this long.
4039 confDELAY_LA DelayLA [0] Load average at which sendmail
4040 will sleep for one second on most
4041 SMTP commands and before accepting
4042 connections. 0 means no limit.
4043 confMAX_ALIAS_RECURSION MaxAliasRecursion
4044 [10] Maximum depth of alias recursion.
4045 confMAX_DAEMON_CHILDREN MaxDaemonChildren
4046 [undefined] The maximum number of
4047 children the daemon will permit. After
4048 this number, connections will be
4049 rejected. If not set or <= 0, there is
4051 confMAX_HEADERS_LENGTH MaxHeadersLength
4052 [32768] Maximum length of the sum
4054 confMAX_MIME_HEADER_LENGTH MaxMimeHeaderLength
4055 [undefined] Maximum length of
4056 certain MIME header field values.
4057 confCONNECTION_RATE_THROTTLE ConnectionRateThrottle
4058 [undefined] The maximum number of
4059 connections permitted per second per
4060 daemon. After this many connections
4061 are accepted, further connections
4062 will be delayed. If not set or <= 0,
4064 confCONNECTION_RATE_WINDOW_SIZE ConnectionRateWindowSize
4065 [60s] Define the length of the
4066 interval for which the number of
4067 incoming connections is maintained.
4068 confWORK_RECIPIENT_FACTOR
4069 RecipientFactor [30000] Cost of each recipient.
4070 confSEPARATE_PROC ForkEachJob [False] Run all deliveries in a
4072 confWORK_CLASS_FACTOR ClassFactor [1800] Priority multiplier for class.
4073 confWORK_TIME_FACTOR RetryFactor [90000] Cost of each delivery attempt.
4074 confQUEUE_SORT_ORDER QueueSortOrder [Priority] Queue sort algorithm:
4075 Priority, Host, Filename, Random,
4076 Modification, or Time.
4077 confMAX_QUEUE_AGE MaxQueueAge [undefined] If set to a value greater
4078 than zero, entries in the queue
4079 will be retried during a queue run
4080 only if the individual retry time
4081 has been reached which is doubled
4082 for each attempt. The maximum retry
4083 time is limited by the specified value.
4084 confMIN_QUEUE_AGE MinQueueAge [0] The minimum amount of time a job
4085 must sit in the queue between queue
4086 runs. This allows you to set the
4087 queue run interval low for better
4088 responsiveness without trying all
4090 confDEF_CHAR_SET DefaultCharSet [unknown-8bit] When converting
4091 unlabeled 8 bit input to MIME, the
4092 character set to use by default.
4093 confSERVICE_SWITCH_FILE ServiceSwitchFile
4094 [/etc/mail/service.switch] The file
4095 to use for the service switch on
4096 systems that do not have a
4097 system-defined switch.
4098 confHOSTS_FILE HostsFile [/etc/hosts] The file to use when doing
4099 "file" type access of hosts names.
4100 confDIAL_DELAY DialDelay [0s] If a connection fails, wait this
4101 long and try again. Zero means "don't
4102 retry". This is to allow "dial on
4103 demand" connections to have enough time
4104 to complete a connection.
4105 confNO_RCPT_ACTION NoRecipientAction
4106 [none] What to do if there are no legal
4107 recipient fields (To:, Cc: or Bcc:)
4108 in the message. Legal values can
4109 be "none" to just leave the
4110 nonconforming message as is, "add-to"
4111 to add a To: header with all the
4112 known recipients (which may expose
4113 blind recipients), "add-apparently-to"
4114 to do the same but use Apparently-To:
4115 instead of To: (strongly discouraged
4116 in accordance with IETF standards),
4117 "add-bcc" to add an empty Bcc:
4118 header, or "add-to-undisclosed" to
4120 ``To: undisclosed-recipients:;''.
4121 confSAFE_FILE_ENV SafeFileEnvironment
4122 [undefined] If set, sendmail will do a
4123 chroot() into this directory before
4125 confCOLON_OK_IN_ADDR ColonOkInAddr [True unless Configuration Level > 6]
4126 If set, colons are treated as a regular
4127 character in addresses. If not set,
4128 they are treated as the introducer to
4129 the RFC 822 "group" syntax. Colons are
4130 handled properly in route-addrs. This
4131 option defaults on for V5 and lower
4132 configuration files.
4133 confMAX_QUEUE_RUN_SIZE MaxQueueRunSize [0] If set, limit the maximum size of
4134 any given queue run to this number of
4135 entries. Essentially, this will stop
4136 reading each queue directory after this
4137 number of entries are reached; it does
4138 _not_ pick the highest priority jobs,
4139 so this should be as large as your
4140 system can tolerate. If not set, there
4142 confMAX_QUEUE_CHILDREN MaxQueueChildren
4143 [undefined] Limits the maximum number
4144 of concurrent queue runners active.
4145 This is to keep system resources used
4146 within a reasonable limit. Relates to
4147 Queue Groups and ForkEachJob.
4148 confMAX_RUNNERS_PER_QUEUE MaxRunnersPerQueue
4149 [1] Only active when MaxQueueChildren
4150 defined. Controls the maximum number
4151 of queue runners (aka queue children)
4152 active at the same time in a work
4153 group. See also MaxQueueChildren.
4154 confDONT_EXPAND_CNAMES DontExpandCnames
4155 [False] If set, $[ ... $] lookups that
4156 do DNS based lookups do not expand
4157 CNAME records. This currently violates
4158 the published standards, but the IETF
4159 seems to be moving toward legalizing
4160 this. For example, if "FTP.Foo.ORG"
4161 is a CNAME for "Cruft.Foo.ORG", then
4162 with this option set a lookup of
4163 "FTP" will return "FTP.Foo.ORG"; if
4164 clear it returns "Cruft.FOO.ORG". N.B.
4165 you may not see any effect until your
4166 downstream neighbors stop doing CNAME
4168 confFROM_LINE UnixFromLine [From $g $d] The From_ line used
4169 when sending to files or programs.
4170 confSINGLE_LINE_FROM_HEADER SingleLineFromHeader
4171 [False] From: lines that have
4172 embedded newlines are unwrapped
4174 confALLOW_BOGUS_HELO AllowBogusHELO [False] Allow HELO SMTP command that
4175 does not include a host name.
4176 confMUST_QUOTE_CHARS MustQuoteChars [.'] Characters to be quoted in a full
4177 name phrase (@,;:\()[] are automatic).
4178 confOPERATORS OperatorChars [.:%@!^/[]+] Address operator
4180 confSMTP_LOGIN_MSG SmtpGreetingMessage
4181 [$j Sendmail $v/$Z; $b]
4182 The initial (spontaneous) SMTP
4183 greeting message. The word "ESMTP"
4184 will be inserted between the first and
4185 second words to convince other
4186 sendmails to try to speak ESMTP.
4187 confDONT_INIT_GROUPS DontInitGroups [False] If set, the initgroups(3)
4188 routine will never be invoked. You
4189 might want to do this if you are
4190 running NIS and you have a large group
4191 map, since this call does a sequential
4192 scan of the map; in a large site this
4193 can cause your ypserv to run
4194 essentially full time. If you set
4195 this, agents run on behalf of users
4196 will only have their primary
4197 (/etc/passwd) group permissions.
4198 confUNSAFE_GROUP_WRITES UnsafeGroupWrites
4199 [True] If set, group-writable
4200 :include: and .forward files are
4201 considered "unsafe", that is, programs
4202 and files cannot be directly referenced
4203 from such files. World-writable files
4204 are always considered unsafe.
4205 Notice: this option is deprecated and
4206 will be removed in future versions;
4207 Set GroupWritableForwardFileSafe
4208 and GroupWritableIncludeFileSafe in
4209 DontBlameSendmail if required.
4210 confCONNECT_ONLY_TO ConnectOnlyTo [undefined] override connection
4211 address (for testing).
4212 confCONTROL_SOCKET_NAME ControlSocketName
4213 [undefined] Control socket for daemon
4215 confDOUBLE_BOUNCE_ADDRESS DoubleBounceAddress
4216 [postmaster] If an error occurs when
4217 sending an error message, send that
4218 "double bounce" error message to this
4219 address. If it expands to an empty
4220 string, double bounces are dropped.
4221 confSOFT_BOUNCE SoftBounce [False] If set, issue temporary errors
4222 (4xy) instead of permanent errors
4223 (5xy). This can be useful during
4224 testing of a new configuration to
4225 avoid erroneous bouncing of mails.
4226 confDEAD_LETTER_DROP DeadLetterDrop [undefined] Filename to save bounce
4227 messages which could not be returned
4228 to the user or sent to postmaster.
4229 If not set, the queue file will
4231 confRRT_IMPLIES_DSN RrtImpliesDsn [False] Return-Receipt-To: header
4232 implies DSN request.
4233 confRUN_AS_USER RunAsUser [undefined] If set, become this user
4234 when reading and delivering mail.
4235 Causes all file reads (e.g., .forward
4236 and :include: files) to be done as
4237 this user. Also, all programs will
4238 be run as this user, and all output
4239 files will be written as this user.
4240 confMAX_RCPTS_PER_MESSAGE MaxRecipientsPerMessage
4241 [infinite] If set, allow no more than
4242 the specified number of recipients in
4243 an SMTP envelope. Further recipients
4244 receive a 452 error code (i.e., they
4245 are deferred for the next delivery
4247 confBAD_RCPT_THROTTLE BadRcptThrottle [infinite] If set and the specified
4248 number of recipients in a single SMTP
4249 transaction have been rejected, sleep
4250 for one second after each subsequent
4251 RCPT command in that transaction.
4252 confDONT_PROBE_INTERFACES DontProbeInterfaces
4253 [False] If set, sendmail will _not_
4254 insert the names and addresses of any
4255 local interfaces into class {w}
4256 (list of known "equivalent" addresses).
4257 If you set this, you must also include
4258 some support for these addresses (e.g.,
4259 in a mailertable entry) -- otherwise,
4260 mail to addresses in this list will
4261 bounce with a configuration error.
4262 If set to "loopback" (without
4263 quotes), sendmail will skip
4264 loopback interfaces (e.g., "lo0").
4265 confPID_FILE PidFile [system dependent] Location of pid
4267 confPROCESS_TITLE_PREFIX ProcessTitlePrefix
4268 [undefined] Prefix string for the
4269 process title shown on 'ps' listings.
4270 confDONT_BLAME_SENDMAIL DontBlameSendmail
4271 [safe] Override sendmail's file
4272 safety checks. This will definitely
4273 compromise system security and should
4274 not be used unless absolutely
4276 confREJECT_MSG - [550 Access denied] The message
4277 given if the access database contains
4278 REJECT in the value portion.
4279 confRELAY_MSG - [550 Relaying denied] The message
4280 given if an unauthorized relaying
4281 attempt is rejected.
4282 confDF_BUFFER_SIZE DataFileBufferSize
4283 [4096] The maximum size of a
4284 memory-buffered data (df) file
4285 before a disk-based file is used.
4286 confXF_BUFFER_SIZE XScriptFileBufferSize
4287 [4096] The maximum size of a
4288 memory-buffered transcript (xf)
4289 file before a disk-based file is
4291 confAUTH_MECHANISMS AuthMechanisms [GSSAPI KERBEROS_V4 DIGEST-MD5
4292 CRAM-MD5] List of authentication
4293 mechanisms for AUTH (separated by
4294 spaces). The advertised list of
4295 authentication mechanisms will be the
4296 intersection of this list and the list
4297 of available mechanisms as determined
4298 by the Cyrus SASL library.
4299 confAUTH_REALM AuthRealm [undefined] The authentication realm
4300 that is passed to the Cyrus SASL
4301 library. If no realm is specified,
4302 $j is used. See KNOWNBUGS.
4303 confDEF_AUTH_INFO DefaultAuthInfo [undefined] Name of file that contains
4304 authentication information for
4305 outgoing connections. This file must
4306 contain the user id, the authorization
4307 id, the password (plain text), the
4308 realm to use, and the list of
4309 mechanisms to try, each on a separate
4310 line and must be readable by root (or
4311 the trusted user) only. If no realm
4312 is specified, $j is used. If no
4313 mechanisms are given in the file,
4314 AuthMechanisms is used. Notice: this
4315 option is deprecated and will be
4316 removed in future versions; it doesn't
4317 work for the MSP since it can't read
4318 the file. Use the authinfo ruleset
4319 instead. See also the section SMTP
4321 confAUTH_OPTIONS AuthOptions [undefined] If this option is 'A'
4322 then the AUTH= parameter for the
4323 MAIL FROM command is only issued
4324 when authentication succeeded.
4325 See doc/op/op.me for more options
4327 confAUTH_MAX_BITS AuthMaxBits [INT_MAX] Limit the maximum encryption
4328 strength for the security layer in
4329 SMTP AUTH (SASL). Default is
4330 essentially unlimited.
4331 confTLS_SRV_OPTIONS TLSSrvOptions If this option is 'V' no client
4332 verification is performed, i.e.,
4333 the server doesn't ask for a
4335 confSERVER_SSL_OPTIONS ServerSSLOptions [undefined] SSL related
4336 options for server side. See
4337 SSL_CTX_set_options(3) for a list.
4338 confCLIENT_SSL_OPTIONS ClientSSLOptions [undefined] SSL related
4339 options for client side. See
4340 SSL_CTX_set_options(3) for a list.
4341 confCIPHER_LIST CipherList [undefined] Cipher list for TLS.
4342 See ciphers(1) for possible values.
4343 confLDAP_DEFAULT_SPEC LDAPDefaultSpec [undefined] Default map
4344 specification for LDAP maps. The
4345 value should only contain LDAP
4346 specific settings such as "-h host
4347 -p port -d bindDN", etc. The
4348 settings will be used for all LDAP
4349 maps unless they are specified in
4350 the individual map specification
4352 confCACERT_PATH CACertPath [undefined] Path to directory with
4353 certificates of CAs which must contain
4354 their hashes as filenames or links.
4355 confCACERT CACertFile [undefined] File containing at least
4357 confSERVER_CERT ServerCertFile [undefined] File containing the
4358 cert of the server, i.e., this cert
4359 is used when sendmail acts as
4361 confSERVER_KEY ServerKeyFile [undefined] File containing the
4362 private key belonging to the server
4364 confCLIENT_CERT ClientCertFile [undefined] File containing the
4365 cert of the client, i.e., this cert
4366 is used when sendmail acts as
4368 confCLIENT_KEY ClientKeyFile [undefined] File containing the
4369 private key belonging to the client
4371 confCRL CRLFile [undefined] File containing certificate
4372 revocation status, useful for X.509v3
4374 confCRL_PATH CRLPath [undefined] Directory containing
4375 hashes pointing to certificate
4376 revocation status files.
4377 confDH_PARAMETERS DHParameters [undefined] File containing the
4379 confDANE DANE [false] Enable DANE support.
4380 confRAND_FILE RandFile [undefined] File containing random
4381 data (use prefix file:) or the
4382 name of the UNIX socket if EGD is
4383 used (use prefix egd:). STARTTLS
4384 requires this option if the compile
4385 flag HASURANDOM is not set (see
4387 confCERT_FINGERPRINT_ALGORITHM CertFingerprintAlgorithm
4388 [undefined] The fingerprint algorithm
4389 (digest) to use for the presented
4391 confSSL_ENGINE SSLEngine [undefined] Name of SSLEngine.
4392 confSSL_ENGINE_PATH SSLEnginePath [undefined] Path to dynamic library
4394 confNICE_QUEUE_RUN NiceQueueRun [undefined] If set, the priority of
4395 queue runners is set the given value
4397 confDIRECT_SUBMISSION_MODIFIERS DirectSubmissionModifiers
4398 [undefined] Defines {daemon_flags}
4399 for direct submissions.
4400 confUSE_MSP UseMSP [undefined] Use as mail submission
4401 program, see sendmail/SECURITY.
4402 confDELIVER_BY_MIN DeliverByMin [0] Minimum time for Deliver By
4403 SMTP Service Extension (RFC 2852).
4404 confREQUIRES_DIR_FSYNC RequiresDirfsync [true] RequiresDirfsync can
4405 be used to turn off the compile time
4406 flag REQUIRES_DIR_FSYNC at runtime.
4407 See sendmail/README for details.
4408 confSHARED_MEMORY_KEY SharedMemoryKey [0] Key for shared memory.
4409 confSHARED_MEMORY_KEY_FILE
4411 [undefined] File where the
4412 automatically selected key for
4413 shared memory is stored.
4414 confFAST_SPLIT FastSplit [1] If set to a value greater than
4415 zero, the initial MX lookups on
4416 addresses is suppressed when they
4417 are sorted which may result in
4418 faster envelope splitting. If the
4419 mail is submitted directly from the
4420 command line, then the value also
4421 limits the number of processes to
4422 deliver the envelopes.
4423 confMAILBOX_DATABASE MailboxDatabase [pw] Type of lookup to find
4424 information about local mailboxes.
4425 confDEQUOTE_OPTS - [empty] Additional options for the
4427 confMAX_NOOP_COMMANDS MaxNOOPCommands [20] Maximum number of "useless"
4428 commands before the SMTP server
4429 will slow down responding.
4430 confHELO_NAME HeloName If defined, use as name for EHLO/HELO
4431 command (instead of $j).
4432 confINPUT_MAIL_FILTERS InputMailFilters
4433 A comma separated list of filters
4434 which determines which filters and
4435 the invocation sequence are
4436 contacted for incoming SMTP
4437 messages. If none are set, no
4438 filters will be contacted.
4439 confMILTER_LOG_LEVEL Milter.LogLevel [9] Log level for input mail filter
4440 actions, defaults to LogLevel.
4441 confMILTER_MACROS_CONNECT Milter.macros.connect
4442 [j, _, {daemon_name}, {if_name},
4443 {if_addr}] Macros to transmit to
4444 milters when a session connection
4446 confMILTER_MACROS_HELO Milter.macros.helo
4447 [{tls_version}, {cipher},
4448 {cipher_bits}, {cert_subject},
4449 {cert_issuer}] Macros to transmit to
4450 milters after HELO/EHLO command.
4451 confMILTER_MACROS_ENVFROM Milter.macros.envfrom
4452 [i, {auth_type}, {auth_authen},
4453 {auth_ssf}, {auth_author},
4454 {mail_mailer}, {mail_host},
4455 {mail_addr}] Macros to transmit to
4456 milters after MAIL FROM command.
4457 confMILTER_MACROS_ENVRCPT Milter.macros.envrcpt
4458 [{rcpt_mailer}, {rcpt_host},
4459 {rcpt_addr}] Macros to transmit to
4460 milters after RCPT TO command.
4461 confMILTER_MACROS_EOM Milter.macros.eom
4462 [{msg_id}] Macros to transmit to
4463 milters after the terminating
4464 DATA '.' is received.
4465 confMILTER_MACROS_EOH Milter.macros.eoh
4466 Macros to transmit to milters
4467 after the end of headers.
4468 confMILTER_MACROS_DATA Milter.macros.data
4469 Macros to transmit to milters
4470 after DATA command is received.
4473 See also the description of OSTYPE for some parameters that can be
4474 tweaked (generally pathnames to mailers).
4476 ClientPortOptions and DaemonPortOptions are special cases since multiple
4477 clients/daemons can be defined. This can be done via
4479 CLIENT_OPTIONS(`field1=value1,field2=value2,...')
4480 DAEMON_OPTIONS(`field1=value1,field2=value2,...')
4482 Note that multiple CLIENT_OPTIONS() commands (and therefore multiple
4483 ClientPortOptions settings) are allowed in order to give settings for each
4484 protocol family (e.g., one for Family=inet and one for Family=inet6). A
4485 restriction placed on one family only affects outgoing connections on that
4488 If DAEMON_OPTIONS is not used, then the default is
4490 DAEMON_OPTIONS(`Port=smtp, Name=MTA')
4491 DAEMON_OPTIONS(`Port=587, Name=MSA, M=E')
4493 If you use one DAEMON_OPTIONS macro, it will alter the parameters
4494 of the first of these. The second will still be defaulted; it
4495 represents a "Message Submission Agent" (MSA) as defined by RFC
4496 2476 (see below). To turn off the default definition for the MSA,
4497 use FEATURE(`no_default_msa') (see also FEATURES). If you use
4498 additional DAEMON_OPTIONS macros, they will add additional daemons.
4500 Example 1: To change the port for the SMTP listener, while
4501 still using the MSA default, use
4502 DAEMON_OPTIONS(`Port=925, Name=MTA')
4504 Example 2: To change the port for the MSA daemon, while still
4505 using the default SMTP port, use
4506 FEATURE(`no_default_msa')
4507 DAEMON_OPTIONS(`Name=MTA')
4508 DAEMON_OPTIONS(`Port=987, Name=MSA, M=E')
4510 Note that if the first of those DAEMON_OPTIONS lines were omitted, then
4511 there would be no listener on the standard SMTP port.
4513 Example 3: To listen on both IPv4 and IPv6 interfaces, use
4515 DAEMON_OPTIONS(`Name=MTA-v4, Family=inet')
4516 DAEMON_OPTIONS(`Name=MTA-v6, Family=inet6')
4518 A "Message Submission Agent" still uses all of the same rulesets for
4519 processing the message (and therefore still allows message rejection via
4520 the check_* rulesets). In accordance with the RFC, the MSA will ensure
4521 that all domains in envelope addresses are fully qualified if the message
4522 is relayed to another MTA. It will also enforce the normal address syntax
4523 rules and log error messages. Additionally, by using the M=a modifier you
4524 can require authentication before messages are accepted by the MSA.
4525 Notice: Do NOT use the 'a' modifier on a public accessible MTA! Finally,
4526 the M=E modifier shown above disables ETRN as required by RFC 2476.
4528 Mail filters can be defined using the INPUT_MAIL_FILTER() and MAIL_FILTER()
4531 INPUT_MAIL_FILTER(`sample', `S=local:/var/run/f1.sock')
4532 MAIL_FILTER(`myfilter', `S=inet:3333@localhost')
4534 The INPUT_MAIL_FILTER() command causes the filter(s) to be called in the
4535 same order they were specified by also setting confINPUT_MAIL_FILTERS. A
4536 filter can be defined without adding it to the input filter list by using
4537 MAIL_FILTER() instead of INPUT_MAIL_FILTER() in your .mc file.
4538 Alternatively, you can reset the list of filters and their order by setting
4539 confINPUT_MAIL_FILTERS option after all INPUT_MAIL_FILTER() commands in
4543 +----------------------------+
4544 | MESSAGE SUBMISSION PROGRAM |
4545 +----------------------------+
4547 The purpose of the message submission program (MSP) is explained
4548 in sendmail/SECURITY. This section contains a list of caveats and
4549 a few hints how for those who want to tweak the default configuration
4550 for it (which is installed as submit.cf).
4552 Notice: do not add options/features to submit.mc unless you are
4553 absolutely sure you need them. Options you may want to change
4556 - confTRUSTED_USERS, FEATURE(`use_ct_file'), and confCT_FILE for
4557 avoiding X-Authentication warnings.
4558 - confTIME_ZONE to change it from the default `USE_TZ'.
4559 - confDELIVERY_MODE is set to interactive in msp.m4 instead
4560 of the default background mode.
4561 - FEATURE(stickyhost) and LOCAL_RELAY to send unqualified addresses
4562 to the LOCAL_RELAY instead of the default relay.
4563 - confRAND_FILE if you use STARTTLS and sendmail is not compiled with
4564 the flag HASURANDOM.
4566 The MSP performs hostname canonicalization by default. As also
4567 explained in sendmail/SECURITY, mail may end up for various DNS
4568 related reasons in the MSP queue. This problem can be minimized by
4571 FEATURE(`nocanonify', `canonify_hosts')
4572 define(`confDIRECT_SUBMISSION_MODIFIERS', `C')
4574 See the discussion about nocanonify for possible side effects.
4576 Some things are not intended to work with the MSP. These include
4577 features that influence the delivery process (e.g., mailertable,
4578 aliases), or those that are only important for a SMTP server (e.g.,
4579 virtusertable, DaemonPortOptions, multiple queues). Moreover,
4580 relaxing certain restrictions (RestrictQueueRun, permissions on
4581 queue directory) or adding features (e.g., enabling prog/file mailer)
4582 can cause security problems.
4584 Other things don't work well with the MSP and require tweaking or
4585 workarounds. For example, to allow for client authentication it
4586 is not just sufficient to provide a client certificate and the
4587 corresponding key, but it is also necessary to make the key group
4588 (smmsp) readable and tell sendmail not to complain about that, i.e.,
4590 define(`confDONT_BLAME_SENDMAIL', `GroupReadableKeyFile')
4592 If the MSP should actually use AUTH then the necessary data
4593 should be placed in a map as explained in SMTP AUTHENTICATION:
4595 FEATURE(`authinfo', `DATABASE_MAP_TYPE /etc/mail/msp-authinfo')
4597 /etc/mail/msp-authinfo should contain an entry like:
4599 AuthInfo:127.0.0.1 "U:smmsp" "P:secret" "M:DIGEST-MD5"
4601 The file and the map created by makemap should be owned by smmsp,
4602 its group should be smmsp, and it should have mode 640. The database
4603 used by the MTA for AUTH must have a corresponding entry.
4604 Additionally the MTA must trust this authentication data so the AUTH=
4605 part will be relayed on to the next hop. This can be achieved by
4606 adding the following to your sendmail.mc file:
4610 R$* $: $&{auth_authen}
4613 Note: the authentication data can leak to local users who invoke
4614 the MSP with debug options or even with -v. For that reason either
4615 an authentication mechanism that does not show the password in the
4616 AUTH dialogue (e.g., DIGEST-MD5) or a different authentication
4617 method like STARTTLS should be used.
4619 feature/msp.m4 defines almost all settings for the MSP. Most of
4620 those should not be changed at all. Some of the features and options
4621 can be overridden if really necessary. It is a bit tricky to do
4622 this, because it depends on the actual way the option is defined
4623 in feature/msp.m4. If it is directly defined (i.e., define()) then
4624 the modified value must be defined after
4628 If it is conditionally defined (i.e., ifdef()) then the desired
4629 value must be defined before the FEATURE line in the .mc file.
4630 To see how the options are defined read feature/msp.m4.
4633 +--------------------------+
4634 | FORMAT OF FILES AND MAPS |
4635 +--------------------------+
4637 Files that define classes, i.e., F{classname}, consist of lines
4638 each of which contains a single element of the class. For example,
4639 /etc/mail/local-host-names may have the following content:
4644 Maps must be created using makemap(8) , e.g.,
4646 makemap hash MAP < MAP
4648 In general, a text file from which a map is created contains lines
4653 where 'key' and 'value' are also called LHS and RHS, respectively.
4654 By default, the delimiter between LHS and RHS is a non-empty sequence
4655 of white space characters.
4658 +------------------+
4659 | DIRECTORY LAYOUT |
4660 +------------------+
4662 Within this directory are several subdirectories, to wit:
4664 m4 General support routines. These are typically
4665 very important and should not be changed without
4666 very careful consideration.
4668 cf The configuration files themselves. They have
4669 ".mc" suffixes, and must be run through m4 to
4670 become complete. The resulting output should
4671 have a ".cf" suffix.
4673 ostype Definitions describing a particular operating
4674 system type. These should always be referenced
4675 using the OSTYPE macro in the .mc file. Examples
4676 include "bsd4.3", "bsd4.4", "sunos3.5", and
4679 domain Definitions describing a particular domain, referenced
4680 using the DOMAIN macro in the .mc file. These are
4681 site dependent; for example, "CS.Berkeley.EDU.m4"
4682 describes hosts in the CS.Berkeley.EDU subdomain.
4684 mailer Descriptions of mailers. These are referenced using
4685 the MAILER macro in the .mc file.
4687 sh Shell files used when building the .cf file from the
4688 .mc file in the cf subdirectory.
4690 feature These hold special orthogonal features that you might
4691 want to include. They should be referenced using
4694 hack Local hacks. These can be referenced using the HACK
4695 macro. They shouldn't be of more than voyeuristic
4696 interest outside the .Berkeley.EDU domain, but who knows?
4698 siteconfig Site configuration -- e.g., tables of locally connected
4702 +------------------------+
4703 | ADMINISTRATIVE DETAILS |
4704 +------------------------+
4706 The following sections detail usage of certain internal parts of the
4707 sendmail.cf file. Read them carefully if you are trying to modify
4708 the current model. If you find the above descriptions adequate, these
4709 should be {boring, confusing, tedious, ridiculous} (pick one or more).
4711 RULESETS (* means built in to sendmail)
4714 1 * Sender rewriting
4715 2 * Recipient rewriting
4716 3 * Canonicalization
4718 5 * Local address rewrite (after aliasing)
4719 1x mailer rules (sender qualification)
4720 2x mailer rules (recipient qualification)
4721 3x mailer rules (sender header qualification)
4722 4x mailer rules (recipient header qualification)
4723 5x mailer subroutines (general)
4724 6x mailer subroutines (general)
4725 7x mailer subroutines (general)
4727 90 Mailertable host stripping
4728 96 Bottom half of Ruleset 3 (ruleset 6 in old sendmail)
4729 97 Hook for recursive ruleset 0 call (ruleset 7 in old sendmail)
4730 98 Local part of ruleset 0 (ruleset 8 in old sendmail)
4735 0 local, prog local and program mailers
4736 1 [e]smtp, relay SMTP channel
4737 2 uucp-* UNIX-to-UNIX Copy Program
4738 3 netnews Network News delivery
4739 4 fax Sam Leffler's HylaFAX software
4740 5 mail11 DECnet mailer
4748 D The local domain -- usually not needed
4749 E reserved for X.400 Relay
4752 H mail Hub (for mail clusters)
4757 M Masquerade (who you claim to be)
4762 R Relay (for unqualified names)
4765 U my UUCP name (if you have a UUCP connection)
4766 V UUCP Relay (class {V} hosts)
4767 W UUCP Relay (class {W} hosts)
4768 X UUCP Relay (class {X} hosts)
4769 Y UUCP Relay (all other hosts)
4776 B domains that are candidates for bestmx lookup
4779 E addresses that should not seem to come from $M
4780 F hosts this system forward for
4781 G domains that should be looked up in genericstable
4786 L addresses that should not be forwarded to $R
4787 M domains that should be mapped to $M
4788 N host/domains that should not be mapped to $M
4789 O operators that indicate network operations (cannot be in local names)
4790 P top level pseudo-domains: BITNET, DECNET, FAX, UUCP, etc.
4792 R domains this system is willing to relay (pass anti-spam filters)
4795 U locally connected UUCP hosts
4796 V UUCP hosts connected to relay $V
4797 W UUCP hosts connected to relay $W
4798 X UUCP hosts connected to relay $X
4799 Y locally connected smart UUCP hosts
4800 Z locally connected domain-ized UUCP hosts
4801 . the class containing only a dot
4802 [ the class containing only a left bracket
4807 1 Local host detection and resolution
4808 2 Local Ruleset 3 additions
4809 3 Local Ruleset 0 additions
4810 4 UUCP Ruleset 0 additions
4811 5 locally interpreted names (overrides $R)
4812 6 local configuration (at top of file)
4813 7 mailer definitions
4814 8 DNS based blocklists
4815 9 special local rulesets (1 and 2)