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) 1998-2004 Sendmail, Inc. and its suppliers.
81 # All rights reserved.
82 # Copyright (c) 1983 Eric P. Allman. All rights reserved.
83 # Copyright (c) 1988, 1993
84 # The Regents of the University of California. All rights reserved.
86 # By using this file, you agree to the terms and conditions set
87 # forth in the LICENSE file which can be found at the top level of
88 # the sendmail distribution.
92 # This is a Berkeley-specific configuration file for HP-UX 9.x.
93 # It applies only to the Computer Science Division at Berkeley,
94 # and should not be used elsewhere. It is provided on the sendmail
95 # distribution as a sample only. To create your own configuration
96 # file, create an appropriate domain file in ../domain, change the
97 # `DOMAIN' macro below to reference that file, and copy the result
98 # to a name of your own choosing.
102 The divert(-1) will delete the crud in the resulting output file.
103 The copyright notice can be replaced by whatever your lawyers require;
104 our lawyers require the one that is included in these files. A copyleft
105 is a copyright by another name. The divert(0) restores regular output.
107 VERSIONID(`<SCCS or RCS version id>')
109 VERSIONID is a macro that stuffs the version information into the
110 resulting file. You could use SCCS, RCS, CVS, something else, or
111 omit it completely. This is not the same as the version id included
112 in SMTP greeting messages -- this is defined in m4/version.m4.
116 You must specify an OSTYPE to properly configure things such as the
117 pathname of the help and status files, the flags needed for the local
118 mailer, and other important things. If you omit it, you will get an
119 error when you try to build the configuration. Look at the ostype
120 directory for the list of known operating system types.
122 DOMAIN(`CS.Berkeley.EDU')dnl
124 This example is specific to the Computer Science Division at Berkeley.
125 You can use "DOMAIN(`generic')" to get a sufficiently bland definition
126 that may well work for you, or you can create a customized domain
127 definition appropriate for your environment.
132 These describe the mailers used at the default CS site. The local
133 mailer is always included automatically. Beware: MAILER declarations
134 should only be followed by LOCAL_* sections. The general rules are
135 that the order should be:
141 local macro definitions
147 There are a few exceptions to this rule. Local macro definitions which
148 influence a FEATURE() should be done before that feature. For example,
149 a define(`PROCMAIL_MAILER_PATH', ...) should be done before
150 FEATURE(`local_procmail').
152 *******************************************************************
153 *** BE SURE YOU CUSTOMIZE THESE FILES! They have some ***
154 *** Berkeley-specific assumptions built in, such as the name ***
155 *** of their UUCP-relay. You'll want to create your own ***
156 *** domain description, and use that in place of ***
157 *** domain/Berkeley.EDU.m4. ***
158 *******************************************************************
161 +----------------------------+
162 | A BRIEF INTRODUCTION TO M4 |
163 +----------------------------+
165 Sendmail uses the M4 macro processor to ``compile'' the configuration
166 files. The most important thing to know is that M4 is stream-based,
167 that is, it doesn't understand about lines. For this reason, in some
168 places you may see the word ``dnl'', which stands for ``delete
169 through newline''; essentially, it deletes all characters starting
170 at the ``dnl'' up to and including the next newline character. In
171 most cases sendmail uses this only to avoid lots of unnecessary
172 blank lines in the output.
174 Other important directives are define(A, B) which defines the macro
175 ``A'' to have value ``B''. Macros are expanded as they are read, so
176 one normally quotes both values to prevent expansion. For example,
178 define(`SMART_HOST', `smart.foo.com')
180 One word of warning: M4 macros are expanded even in lines that appear
181 to be comments. For example, if you have
183 # See FEATURE(`foo') above
185 it will not do what you expect, because the FEATURE(`foo') will be
186 expanded. This also applies to
188 # And then define the $X macro to be the return address
190 because ``define'' is an M4 keyword. If you want to use them, surround
191 them with directed quotes, `like this'.
193 Since m4 uses single quotes (opening "`" and closing "'") to quote
194 arguments, those quotes can't be used in arguments. For example,
195 it is not possible to define a rejection message containing a single
196 quote. Usually there are simple workarounds by changing those
197 messages; in the worst case it might be ok to change the value
198 directly in the generated .cf file, which however is not advised.
204 This package requires a post-V7 version of m4; if you are running the
205 4.2bsd, SysV.2, or 7th Edition version. SunOS's /usr/5bin/m4 or
206 BSD-Net/2's m4 both work. GNU m4 version 1.1 or later also works.
207 Unfortunately, the M4 on BSDI 1.0 doesn't work -- you'll have to use a
208 Net/2 or GNU version. GNU m4 is available from
209 ftp://ftp.gnu.org/pub/gnu/m4/m4-1.4.tar.gz (check for the latest version).
210 EXCEPTIONS: DEC's m4 on Digital UNIX 4.x is broken (3.x is fine). Use GNU
218 sendmail 8.9 has introduced a new configuration directory for sendmail
219 related files, /etc/mail. The new files available for sendmail 8.9 --
220 the class {R} /etc/mail/relay-domains and the access database
221 /etc/mail/access -- take advantage of this new directory. Beginning with
222 8.10, all files will use this directory by default (some options may be
223 set by OSTYPE() files). This new directory should help to restore
224 uniformity to sendmail's file locations.
226 Below is a table of some of the common changes:
228 Old filename New filename
229 ------------ ------------
230 /etc/bitdomain /etc/mail/bitdomain
231 /etc/domaintable /etc/mail/domaintable
232 /etc/genericstable /etc/mail/genericstable
233 /etc/uudomain /etc/mail/uudomain
234 /etc/virtusertable /etc/mail/virtusertable
235 /etc/userdb /etc/mail/userdb
237 /etc/aliases /etc/mail/aliases
238 /etc/sendmail/aliases /etc/mail/aliases
239 /etc/ucbmail/aliases /etc/mail/aliases
240 /usr/adm/sendmail/aliases /etc/mail/aliases
241 /usr/lib/aliases /etc/mail/aliases
242 /usr/lib/mail/aliases /etc/mail/aliases
243 /usr/ucblib/aliases /etc/mail/aliases
245 /etc/sendmail.cw /etc/mail/local-host-names
246 /etc/mail/sendmail.cw /etc/mail/local-host-names
247 /etc/sendmail/sendmail.cw /etc/mail/local-host-names
249 /etc/sendmail.ct /etc/mail/trusted-users
251 /etc/sendmail.oE /etc/mail/error-header
253 /etc/sendmail.hf /etc/mail/helpfile
254 /etc/mail/sendmail.hf /etc/mail/helpfile
255 /usr/ucblib/sendmail.hf /etc/mail/helpfile
256 /etc/ucbmail/sendmail.hf /etc/mail/helpfile
257 /usr/lib/sendmail.hf /etc/mail/helpfile
258 /usr/share/lib/sendmail.hf /etc/mail/helpfile
259 /usr/share/misc/sendmail.hf /etc/mail/helpfile
260 /share/misc/sendmail.hf /etc/mail/helpfile
262 /etc/service.switch /etc/mail/service.switch
264 /etc/sendmail.st /etc/mail/statistics
265 /etc/mail/sendmail.st /etc/mail/statistics
266 /etc/mailer/sendmail.st /etc/mail/statistics
267 /etc/sendmail/sendmail.st /etc/mail/statistics
268 /usr/lib/sendmail.st /etc/mail/statistics
269 /usr/ucblib/sendmail.st /etc/mail/statistics
271 Note that all of these paths actually use a new m4 macro MAIL_SETTINGS_DIR
272 to create the pathnames. The default value of this variable is
273 `/etc/mail/'. If you set this macro to a different value, you MUST include
276 Notice: all filenames used in a .mc (or .cf) file should be absolute
277 (starting at the root, i.e., with '/'). Relative filenames most
278 likely cause surprises during operations (unless otherwise noted).
285 You MUST define an operating system environment, or the configuration
286 file build will puke. There are several environments available; look
287 at the "ostype" directory for the current list. This macro changes
288 things like the location of the alias file and queue directory. Some
289 of these files are identical to one another.
291 It is IMPERATIVE that the OSTYPE occur before any MAILER definitions.
292 In general, the OSTYPE macro should go immediately after any version
293 information, and MAILER definitions should always go last.
295 Operating system definitions are usually easy to write. They may define
296 the following variables (everything defaults, so an ostype file may be
297 empty). Unfortunately, the list of configuration-supported systems is
298 not as broad as the list of source-supported systems, since many of
299 the source contributors do not include corresponding ostype files.
301 ALIAS_FILE [/etc/mail/aliases] The location of the text version
302 of the alias file(s). It can be a comma-separated
303 list of names (but be sure you quote values with
304 commas in them -- for example, use
305 define(`ALIAS_FILE', `a,b')
306 to get "a" and "b" both listed as alias files;
307 otherwise the define() primitive only sees "a").
308 HELP_FILE [/etc/mail/helpfile] The name of the file
309 containing information printed in response to
310 the SMTP HELP command.
311 QUEUE_DIR [/var/spool/mqueue] The directory containing
312 queue files. To use multiple queues, supply
313 a value ending with an asterisk. For
314 example, /var/spool/mqueue/qd* will use all of the
315 directories or symbolic links to directories
316 beginning with 'qd' in /var/spool/mqueue as queue
317 directories. The names 'qf', 'df', and 'xf' are
318 reserved as specific subdirectories for the
319 corresponding queue file types as explained in
320 doc/op/op.me. See also QUEUE GROUP DEFINITIONS.
321 MSP_QUEUE_DIR [/var/spool/clientmqueue] The directory containing
322 queue files for the MSP (Mail Submission Program,
323 see sendmail/SECURITY).
324 STATUS_FILE [/etc/mail/statistics] The file containing status
326 LOCAL_MAILER_PATH [/bin/mail] The program used to deliver local mail.
327 LOCAL_MAILER_FLAGS [Prmn9] The flags used by the local mailer. The
328 flags lsDFMAw5:/|@q are always included.
329 LOCAL_MAILER_ARGS [mail -d $u] The arguments passed to deliver local
331 LOCAL_MAILER_MAX [undefined] If defined, the maximum size of local
332 mail that you are willing to accept.
333 LOCAL_MAILER_MAXMSGS [undefined] If defined, the maximum number of
334 messages to deliver in a single connection. Only
335 useful for LMTP local mailers.
336 LOCAL_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
337 that ARRIVE from an address that resolves to the
338 local mailer and which are converted to MIME will be
339 labeled with this character set.
340 LOCAL_MAILER_EOL [undefined] If defined, the string to use as the
341 end of line for the local mailer.
342 LOCAL_MAILER_DSN_DIAGNOSTIC_CODE
343 [X-Unix] The DSN Diagnostic-Code value for the
344 local mailer. This should be changed with care.
345 LOCAL_SHELL_PATH [/bin/sh] The shell used to deliver piped email.
346 LOCAL_SHELL_FLAGS [eu9] The flags used by the shell mailer. The
347 flags lsDFM are always included.
348 LOCAL_SHELL_ARGS [sh -c $u] The arguments passed to deliver "prog"
350 LOCAL_SHELL_DIR [$z:/] The directory search path in which the
352 LOCAL_MAILER_QGRP [undefined] The queue group for the local mailer.
353 USENET_MAILER_PATH [/usr/lib/news/inews] The name of the program
355 USENET_MAILER_FLAGS [rsDFMmn] The mailer flags for the usenet mailer.
356 USENET_MAILER_ARGS [-m -h -n] The command line arguments for the
357 usenet mailer. NOTE: Some versions of inews
358 (such as those shipped with newer versions of INN)
359 use different flags. Double check the defaults
360 against the inews man page.
361 USENET_MAILER_MAX [undefined] The maximum size of messages that will
362 be accepted by the usenet mailer.
363 USENET_MAILER_QGRP [undefined] The queue group for the usenet mailer.
364 SMTP_MAILER_FLAGS [undefined] Flags added to SMTP mailer. Default
365 flags are `mDFMuX' for all SMTP-based mailers; the
366 "esmtp" mailer adds `a'; "smtp8" adds `8'; and
368 RELAY_MAILER_FLAGS [undefined] Flags added to the relay mailer. Default
369 flags are `mDFMuX' for all SMTP-based mailers; the
370 relay mailer adds `a8'. If this is not defined,
371 then SMTP_MAILER_FLAGS is used.
372 SMTP_MAILER_MAX [undefined] The maximum size of messages that will
373 be transported using the smtp, smtp8, esmtp, or dsmtp
375 SMTP_MAILER_MAXMSGS [undefined] If defined, the maximum number of
376 messages to deliver in a single connection for the
377 smtp, smtp8, esmtp, or dsmtp mailers.
378 SMTP_MAILER_MAXRCPTS [undefined] If defined, the maximum number of
379 recipients to deliver in a single connection for the
380 smtp, smtp8, esmtp, or dsmtp mailers.
381 SMTP_MAILER_ARGS [TCP $h] The arguments passed to the smtp mailer.
382 About the only reason you would want to change this
383 would be to change the default port.
384 ESMTP_MAILER_ARGS [TCP $h] The arguments passed to the esmtp mailer.
385 SMTP8_MAILER_ARGS [TCP $h] The arguments passed to the smtp8 mailer.
386 DSMTP_MAILER_ARGS [TCP $h] The arguments passed to the dsmtp mailer.
387 RELAY_MAILER_ARGS [TCP $h] The arguments passed to the relay mailer.
388 SMTP_MAILER_QGRP [undefined] The queue group for the smtp mailer.
389 ESMTP_MAILER_QGRP [undefined] The queue group for the esmtp mailer.
390 SMTP8_MAILER_QGRP [undefined] The queue group for the smtp8 mailer.
391 DSMTP_MAILER_QGRP [undefined] The queue group for the dsmtp mailer.
392 RELAY_MAILER_QGRP [undefined] The queue group for the relay mailer.
393 RELAY_MAILER_MAXMSGS [undefined] If defined, the maximum number of
394 messages to deliver in a single connection for the
396 SMTP_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
397 that ARRIVE from an address that resolves to one of
398 the SMTP mailers and which are converted to MIME will
399 be labeled with this character set.
400 UUCP_MAILER_PATH [/usr/bin/uux] The program used to send UUCP mail.
401 UUCP_MAILER_FLAGS [undefined] Flags added to UUCP mailer. Default
402 flags are `DFMhuU' (and `m' for uucp-new mailer,
403 minus `U' for uucp-dom mailer).
404 UUCP_MAILER_ARGS [uux - -r -z -a$g -gC $h!rmail ($u)] The arguments
405 passed to the UUCP mailer.
406 UUCP_MAILER_MAX [100000] The maximum size message accepted for
407 transmission by the UUCP mailers.
408 UUCP_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
409 that ARRIVE from an address that resolves to one of
410 the UUCP mailers and which are converted to MIME will
411 be labeled with this character set.
412 UUCP_MAILER_QGRP [undefined] The queue group for the UUCP mailers.
413 FAX_MAILER_PATH [/usr/local/lib/fax/mailfax] The program used to
415 FAX_MAILER_ARGS [mailfax $u $h $f] The arguments passed to the FAX
417 FAX_MAILER_MAX [100000] The maximum size message accepted for
419 POP_MAILER_PATH [/usr/lib/mh/spop] The pathname of the POP mailer.
420 POP_MAILER_FLAGS [Penu] Flags added to POP mailer. Flags lsDFMq
422 POP_MAILER_ARGS [pop $u] The arguments passed to the POP mailer.
423 POP_MAILER_QGRP [undefined] The queue group for the pop mailer.
424 PROCMAIL_MAILER_PATH [/usr/local/bin/procmail] The path to the procmail
425 program. This is also used by
426 FEATURE(`local_procmail').
427 PROCMAIL_MAILER_FLAGS [SPhnu9] Flags added to Procmail mailer. Flags
428 DFM are always set. This is NOT used by
429 FEATURE(`local_procmail'); tweak LOCAL_MAILER_FLAGS
431 PROCMAIL_MAILER_ARGS [procmail -Y -m $h $f $u] The arguments passed to
432 the Procmail mailer. This is NOT used by
433 FEATURE(`local_procmail'); tweak LOCAL_MAILER_ARGS
435 PROCMAIL_MAILER_MAX [undefined] If set, the maximum size message that
436 will be accepted by the procmail mailer.
437 PROCMAIL_MAILER_QGRP [undefined] The queue group for the procmail mailer.
438 MAIL11_MAILER_PATH [/usr/etc/mail11] The path to the mail11 mailer.
439 MAIL11_MAILER_FLAGS [nsFx] Flags for the mail11 mailer.
440 MAIL11_MAILER_ARGS [mail11 $g $x $h $u] Arguments passed to the mail11
442 MAIL11_MAILER_QGRP [undefined] The queue group for the mail11 mailer.
443 PH_MAILER_PATH [/usr/local/etc/phquery] The path to the phquery
445 PH_MAILER_FLAGS [ehmu] Flags for the phquery mailer. Flags nrDFM
447 PH_MAILER_ARGS [phquery -- $u] -- arguments to the phquery mailer.
448 PH_MAILER_QGRP [undefined] The queue group for the ph mailer.
449 CYRUS_MAILER_FLAGS [Ah5@/:|] The flags used by the cyrus mailer. The
450 flags lsDFMnPq are always included.
451 CYRUS_MAILER_PATH [/usr/cyrus/bin/deliver] The program used to deliver
453 CYRUS_MAILER_ARGS [deliver -e -m $h -- $u] The arguments passed
454 to deliver cyrus mail.
455 CYRUS_MAILER_MAX [undefined] If set, the maximum size message that
456 will be accepted by the cyrus mailer.
457 CYRUS_MAILER_USER [cyrus:mail] The user and group to become when
458 running the cyrus mailer.
459 CYRUS_MAILER_QGRP [undefined] The queue group for the cyrus mailer.
460 CYRUS_BB_MAILER_FLAGS [u] The flags used by the cyrusbb mailer.
461 The flags lsDFMnP are always included.
462 CYRUS_BB_MAILER_ARGS [deliver -e -m $u] The arguments passed
463 to deliver cyrusbb mail.
464 CYRUSV2_MAILER_FLAGS [A@/:|m] The flags used by the cyrusv2 mailer. The
465 flags lsDFMnqXz are always included.
466 CYRUSV2_MAILER_MAXMSGS [undefined] If defined, the maximum number of
467 messages to deliver in a single connection for the
469 CYRUSV2_MAILER_MAXRCPTS [undefined] If defined, the maximum number of
470 recipients to deliver in a single connection for the
472 CYRUSV2_MAILER_ARGS [FILE /var/imap/socket/lmtp] The arguments passed
473 to the cyrusv2 mailer. This can be used to
474 change the name of the Unix domain socket, or
475 to switch to delivery via TCP (e.g., `TCP $h lmtp')
476 CYRUSV2_MAILER_QGRP [undefined] The queue group for the cyrusv2 mailer.
477 CYRUSV2_MAILER_CHARSET [undefined] If defined, messages containing 8-bit data
478 that ARRIVE from an address that resolves to one the
479 Cyrus mailer and which are converted to MIME will
480 be labeled with this character set.
481 confEBINDIR [/usr/libexec] The directory for executables.
482 Currently used for FEATURE(`local_lmtp') and
484 QPAGE_MAILER_FLAGS [mDFMs] The flags used by the qpage mailer.
485 QPAGE_MAILER_PATH [/usr/local/bin/qpage] The program used to deliver
487 QPAGE_MAILER_ARGS [qpage -l0 -m -P$u] The arguments passed
488 to deliver qpage mail.
489 QPAGE_MAILER_MAX [4096] If set, the maximum size message that
490 will be accepted by the qpage mailer.
491 QPAGE_MAILER_QGRP [undefined] The queue group for the qpage mailer.
492 LOCAL_PROG_QGRP [undefined] The queue group for the prog mailer.
494 Note: to tweak Name_MAILER_FLAGS use the macro MODIFY_MAILER_FLAGS:
495 MODIFY_MAILER_FLAGS(`Name', `change') where Name is the first part of
496 the macro Name_MAILER_FLAGS and change can be: flags that should
497 be used directly (thus overriding the default value), or if it
498 starts with `+' (`-') then those flags are added to (removed from)
499 the default value. Example:
501 MODIFY_MAILER_FLAGS(`LOCAL', `+e')
503 will add the flag `e' to LOCAL_MAILER_FLAGS. Notice: there are
504 several smtp mailers all of which are manipulated individually.
505 See the section MAILERS for the available mailer names.
506 WARNING: The FEATUREs local_lmtp and local_procmail set LOCAL_MAILER_FLAGS
507 unconditionally, i.e., without respecting any definitions in an
515 You will probably want to collect domain-dependent defines into one
516 file, referenced by the DOMAIN macro. For example, the Berkeley
517 domain file includes definitions for several internal distinguished
520 UUCP_RELAY The host that will accept UUCP-addressed email.
521 If not defined, all UUCP sites must be directly
523 BITNET_RELAY The host that will accept BITNET-addressed email.
524 If not defined, the .BITNET pseudo-domain won't work.
525 DECNET_RELAY The host that will accept DECNET-addressed email.
526 If not defined, the .DECNET pseudo-domain and addresses
527 of the form node::user will not work.
528 FAX_RELAY The host that will accept mail to the .FAX pseudo-domain.
529 The "fax" mailer overrides this value.
530 LOCAL_RELAY The site that will handle unqualified names -- that
531 is, names without an @domain extension.
532 Normally MAIL_HUB is preferred for this function.
533 LOCAL_RELAY is mostly useful in conjunction with
534 FEATURE(`stickyhost') -- see the discussion of
535 stickyhost below. If not set, they are assumed to
536 belong on this machine. This allows you to have a
537 central site to store a company- or department-wide
538 alias database. This only works at small sites,
539 and only with some user agents.
540 LUSER_RELAY The site that will handle lusers -- that is, apparently
541 local names that aren't local accounts or aliases. To
542 specify a local user instead of a site, set this to
545 Any of these can be either ``mailer:hostname'' (in which case the
546 mailer is the internal mailer name, such as ``uucp-new'' and the hostname
547 is the name of the host as appropriate for that mailer) or just a
548 ``hostname'', in which case a default mailer type (usually ``relay'',
549 a variant on SMTP) is used. WARNING: if you have a wildcard MX
550 record matching your domain, you probably want to define these to
551 have a trailing dot so that you won't get the mail diverted back
554 The domain file can also be used to define a domain name, if needed
555 (using "DD<domain>") and set certain site-wide features. If all hosts
556 at your site masquerade behind one email name, you could also use
559 You do not have to define a domain -- in particular, if you are a
560 single machine sitting off somewhere, it is probably more work than
561 it's worth. This is just a mechanism for combining "domain dependent
562 knowledge" into one place.
569 There are fewer mailers supported in this version than the previous
570 version, owing mostly to a simpler world. As a general rule, put the
571 MAILER definitions last in your .mc file.
573 local The local and prog mailers. You will almost always
574 need these; the only exception is if you relay ALL
575 your mail to another site. This mailer is included
578 smtp The Simple Mail Transport Protocol mailer. This does
579 not hide hosts behind a gateway or another other
580 such hack; it assumes a world where everyone is
581 running the name server. This file actually defines
582 five mailers: "smtp" for regular (old-style) SMTP to
583 other servers, "esmtp" for extended SMTP to other
584 servers, "smtp8" to do SMTP to other servers without
585 converting 8-bit data to MIME (essentially, this is
586 your statement that you know the other end is 8-bit
587 clean even if it doesn't say so), "dsmtp" to do on
588 demand delivery, and "relay" for transmission to the
589 RELAY_HOST, LUSER_RELAY, or MAIL_HUB.
591 uucp The UNIX-to-UNIX Copy Program mailer. Actually, this
592 defines two mailers, "uucp-old" (a.k.a. "uucp") and
593 "uucp-new" (a.k.a. "suucp"). The latter is for when you
594 know that the UUCP mailer at the other end can handle
595 multiple recipients in one transfer. If the smtp mailer
596 is included in your configuration, two other mailers
597 ("uucp-dom" and "uucp-uudom") are also defined [warning: you
598 MUST specify MAILER(`smtp') before MAILER(`uucp')]. When you
599 include the uucp mailer, sendmail looks for all names in
600 class {U} and sends them to the uucp-old mailer; all
601 names in class {Y} are sent to uucp-new; and all
602 names in class {Z} are sent to uucp-uudom. Note that
603 this is a function of what version of rmail runs on
604 the receiving end, and hence may be out of your control.
605 See the section below describing UUCP mailers in more
608 usenet Usenet (network news) delivery. If this is specified,
609 an extra rule is added to ruleset 0 that forwards all
610 local email for users named ``group.usenet'' to the
611 ``inews'' program. Note that this works for all groups,
612 and may be considered a security problem.
614 fax Facsimile transmission. This is experimental and based
615 on Sam Leffler's HylaFAX software. For more information,
616 see http://www.hylafax.org/.
618 pop Post Office Protocol.
620 procmail An interface to procmail (does not come with sendmail).
621 This is designed to be used in mailertables. For example,
622 a common question is "how do I forward all mail for a given
623 domain to a single person?". If you have this mailer
624 defined, you could set up a mailertable reading:
626 host.com procmail:/etc/procmailrcs/host.com
628 with the file /etc/procmailrcs/host.com reading:
630 :0 # forward mail for host.com
631 ! -oi -f $1 person@other.host
633 This would arrange for (anything)@host.com to be sent
634 to person@other.host. In a procmail script, $1 is the
635 name of the sender and $2 is the name of the recipient.
636 If you use this with FEATURE(`local_procmail'), the FEATURE
637 should be listed first.
639 Of course there are other ways to solve this particular
640 problem, e.g., a catch-all entry in a virtusertable.
642 mail11 The DECnet mail11 mailer, useful only if you have the mail11
643 program from gatekeeper.dec.com:/pub/DEC/gwtools (and
644 DECnet, of course). This is for Phase IV DECnet support;
645 if you have Phase V at your site you may have additional
648 phquery The phquery program. This is somewhat counterintuitively
649 referenced as the "ph" mailer internally. It can be used
650 to do CCSO name server lookups. The phquery program, which
651 this mailer uses, is distributed with the ph client.
653 cyrus The cyrus and cyrusbb mailers. The cyrus mailer delivers to
654 a local cyrus user. this mailer can make use of the
655 "user+detail@local.host" syntax (see
656 FEATURE(`preserve_local_plus_detail')); it will deliver the
657 mail to the user's "detail" mailbox if the mailbox's ACL
658 permits. The cyrusbb mailer delivers to a system-wide
659 cyrus mailbox if the mailbox's ACL permits. The cyrus
660 mailer must be defined after the local mailer.
662 cyrusv2 The mailer for Cyrus v2.x. The cyrusv2 mailer delivers to
663 local cyrus users via LMTP. This mailer can make use of the
664 "user+detail@local.host" syntax (see
665 FEATURE(`preserve_local_plus_detail')); it will deliver the
666 mail to the user's "detail" mailbox if the mailbox's ACL
667 permits. The cyrusv2 mailer must be defined after the
670 qpage A mailer for QuickPage, a pager interface. See
671 http://www.qpage.org/ for further information.
673 The local mailer accepts addresses of the form "user+detail", where
674 the "+detail" is not used for mailbox matching but is available
675 to certain local mail programs (in particular, see
676 FEATURE(`local_procmail')). For example, "eric", "eric+sendmail", and
677 "eric+sww" all indicate the same user, but additional arguments <null>,
678 "sendmail", and "sww" may be provided for use in sorting mail.
685 Special features can be requested using the "FEATURE" macro. For
686 example, the .mc line:
688 FEATURE(`use_cw_file')
690 tells sendmail that you want to have it read an /etc/mail/local-host-names
691 file to get values for class {w}. A FEATURE may contain up to 9
692 optional parameters -- for example:
694 FEATURE(`mailertable', `dbm /usr/lib/mailertable')
696 The default database map type for the table features can be set with
698 define(`DATABASE_MAP_TYPE', `dbm')
700 which would set it to use ndbm databases. The default is the Berkeley DB
701 hash database format. Note that you must still declare a database map type
702 if you specify an argument to a FEATURE. DATABASE_MAP_TYPE is only used
703 if no argument is given for the FEATURE. It must be specified before any
704 feature that uses a map.
706 Also, features which can take a map definition as an argument can also take
707 the special keyword `LDAP'. If that keyword is used, the map will use the
708 LDAP definition described in the ``USING LDAP FOR ALIASES, MAPS, AND
709 CLASSES'' section below.
711 Available features are:
713 use_cw_file Read the file /etc/mail/local-host-names file to get
714 alternate names for this host. This might be used if you
715 were on a host that MXed for a dynamic set of other hosts.
716 If the set is static, just including the line "Cw<name1>
717 <name2> ..." (where the names are fully qualified domain
718 names) is probably superior. The actual filename can be
719 overridden by redefining confCW_FILE.
721 use_ct_file Read the file /etc/mail/trusted-users file to get the
722 names of users that will be ``trusted'', that is, able to
723 set their envelope from address using -f without generating
724 a warning message. The actual filename can be overridden
725 by redefining confCT_FILE.
727 redirect Reject all mail addressed to "address.REDIRECT" with
728 a ``551 User has moved; please try <address>'' message.
729 If this is set, you can alias people who have left
730 to their new address with ".REDIRECT" appended.
732 nouucp Don't route UUCP addresses. This feature takes one
734 `reject': reject addresses which have "!" in the local
735 part unless it originates from a system
736 that is allowed to relay.
737 `nospecial': don't do anything special with "!".
738 Warnings: 1. See the notice in the anti-spam section.
739 2. don't remove "!" from OperatorChars if `reject' is
742 nocanonify Don't pass addresses to $[ ... $] for canonification
743 by default, i.e., host/domain names are considered canonical,
744 except for unqualified names, which must not be used in this
745 mode (violation of the standard). It can be changed by
746 setting the DaemonPortOptions modifiers (M=). That is,
747 FEATURE(`nocanonify') will be overridden by setting the
748 'c' flag. Conversely, if FEATURE(`nocanonify') is not used,
749 it can be emulated by setting the 'C' flag
750 (DaemonPortOptions=Modifiers=C). This would generally only
751 be used by sites that only act as mail gateways or which have
752 user agents that do full canonification themselves. You may
754 "define(`confBIND_OPTS', `-DNSRCH -DEFNAMES')" to turn off
755 the usual resolver options that do a similar thing.
757 An exception list for FEATURE(`nocanonify') can be
758 specified with CANONIFY_DOMAIN or CANONIFY_DOMAIN_FILE,
759 i.e., a list of domains which are nevertheless passed to
760 $[ ... $] for canonification. This is useful to turn on
761 canonification for local domains, e.g., use
762 CANONIFY_DOMAIN(`my.domain my') to canonify addresses
763 which end in "my.domain" or "my".
764 Another way to require canonification in the local
765 domain is CANONIFY_DOMAIN(`$=m').
767 A trailing dot is added to addresses with more than
768 one component in it such that other features which
769 expect a trailing dot (e.g., virtusertable) will
772 If `canonify_hosts' is specified as parameter, i.e.,
773 FEATURE(`nocanonify', `canonify_hosts'), then
774 addresses which have only a hostname, e.g.,
775 <user@host>, will be canonified (and hopefully fully
778 stickyhost This feature is sometimes used with LOCAL_RELAY,
779 although it can be used for a different effect with
782 When used without MAIL_HUB, email sent to
783 "user@local.host" are marked as "sticky" -- that
784 is, the local addresses aren't matched against UDB,
785 don't go through ruleset 5, and are not forwarded to
786 the LOCAL_RELAY (if defined).
788 With MAIL_HUB, mail addressed to "user@local.host"
789 is forwarded to the mail hub, with the envelope
790 address still remaining "user@local.host".
791 Without stickyhost, the envelope would be changed
792 to "user@mail_hub", in order to protect against
795 mailertable Include a "mailer table" which can be used to override
796 routing for particular domains (which are not in class {w},
797 i.e. local host names). The argument of the FEATURE may be
798 the key definition. If none is specified, the definition
801 hash /etc/mail/mailertable
803 Keys in this database are fully qualified domain names
804 or partial domains preceded by a dot -- for example,
805 "vangogh.CS.Berkeley.EDU" or ".CS.Berkeley.EDU". As a
806 special case of the latter, "." matches any domain not
807 covered by other keys. Values must be of the form:
809 where "mailer" is the internal mailer name, and "domain"
810 is where to send the message. These maps are not
811 reflected into the message header. As a special case,
814 will forward to the indicated user using the local mailer,
816 will forward to the original user in the e-mail address
817 using the local mailer, and
819 error:D.S.N:code message
820 will give an error message with the indicated SMTP reply
821 code and message, where D.S.N is an RFC 1893 compliant
824 domaintable Include a "domain table" which can be used to provide
825 domain name mapping. Use of this should really be
826 limited to your own domains. It may be useful if you
827 change names (e.g., your company changes names from
828 oldname.com to newname.com). The argument of the
829 FEATURE may be the key definition. If none is specified,
830 the definition used is:
832 hash /etc/mail/domaintable
834 The key in this table is the domain name; the value is
835 the new (fully qualified) domain. Anything in the
836 domaintable is reflected into headers; that is, this
837 is done in ruleset 3.
839 bitdomain Look up bitnet hosts in a table to try to turn them into
840 internet addresses. The table can be built using the
841 bitdomain program contributed by John Gardiner Myers.
842 The argument of the FEATURE may be the key definition; if
843 none is specified, the definition used is:
845 hash /etc/mail/bitdomain
847 Keys are the bitnet hostname; values are the corresponding
850 uucpdomain Similar feature for UUCP hosts. The default map definition
853 hash /etc/mail/uudomain
855 At the moment there is no automagic tool to build this
859 Include the local host domain even on locally delivered
860 mail. Normally it is not added on unqualified names.
861 However, if you use a shared message store but do not use
862 the same user name space everywhere, you may need the host
863 name on local names. An optional argument specifies
864 another domain to be added than the local.
866 allmasquerade If masquerading is enabled (using MASQUERADE_AS), this
867 feature will cause recipient addresses to also masquerade
868 as being from the masquerade host. Normally they get
869 the local hostname. Although this may be right for
870 ordinary users, it can break local aliases. For example,
871 if you send to "localalias", the originating sendmail will
872 find that alias and send to all members, but send the
873 message with "To: localalias@masqueradehost". Since that
874 alias likely does not exist, replies will fail. Use this
875 feature ONLY if you can guarantee that the ENTIRE
876 namespace on your masquerade host supersets all the
880 Normally, any hosts listed in class {w} are masqueraded. If
881 this feature is given, only the hosts listed in class {M} (see
882 below: MASQUERADE_DOMAIN) are masqueraded. This is useful
883 if you have several domains with disjoint namespaces hosted
886 masquerade_entire_domain
887 If masquerading is enabled (using MASQUERADE_AS) and
888 MASQUERADE_DOMAIN (see below) is set, this feature will
889 cause addresses to be rewritten such that the masquerading
890 domains are actually entire domains to be hidden. All
891 hosts within the masquerading domains will be rewritten
892 to the masquerade name (used in MASQUERADE_AS). For example,
895 MASQUERADE_AS(`masq.com')
896 MASQUERADE_DOMAIN(`foo.org')
897 MASQUERADE_DOMAIN(`bar.com')
899 then *foo.org and *bar.com are converted to masq.com. Without
900 this feature, only foo.org and bar.com are masqueraded.
902 NOTE: only domains within your jurisdiction and
903 current hierarchy should be masqueraded using this.
906 This feature prevents the local mailer from masquerading even
907 if MASQUERADE_AS is used. MASQUERADE_AS will only have effect
908 on addresses of mail going outside the local domain.
911 If masquerading is enabled (using MASQUERADE_AS) or the
912 genericstable is in use, this feature will cause envelope
913 addresses to also masquerade as being from the masquerade
914 host. Normally only the header addresses are masqueraded.
916 genericstable This feature will cause unqualified addresses (i.e., without
917 a domain) and addresses with a domain listed in class {G}
918 to be looked up in a map and turned into another ("generic")
919 form, which can change both the domain name and the user name.
920 Notice: if you use an MSP (as it is default starting with
921 8.12), the MTA will only receive qualified addresses from the
922 MSP (as required by the RFCs). Hence you need to add your
923 domain to class {G}. This feature is similar to the userdb
924 functionality. The same types of addresses as for
925 masquerading are looked up, i.e., only header sender
926 addresses unless the allmasquerade and/or masquerade_envelope
927 features are given. Qualified addresses must have the domain
928 part in class {G}; entries can be added to this class by the
929 macros GENERICS_DOMAIN or GENERICS_DOMAIN_FILE (analogously
930 to MASQUERADE_DOMAIN and MASQUERADE_DOMAIN_FILE, see below).
932 The argument of FEATURE(`genericstable') may be the map
933 definition; the default map definition is:
935 hash /etc/mail/genericstable
937 The key for this table is either the full address, the domain
938 (with a leading @; the localpart is passed as first argument)
939 or the unqualified username (tried in the order mentioned);
940 the value is the new user address. If the new user address
941 does not include a domain, it will be qualified in the standard
942 manner, i.e., using $j or the masquerade name. Note that the
943 address being looked up must be fully qualified. For local
944 mail, it is necessary to use FEATURE(`always_add_domain')
945 for the addresses to be qualified.
946 The "+detail" of an address is passed as %1, so entries like
948 old+*@foo.org new+%1@example.com
949 gen+*@foo.org %1@example.com
951 and other forms are possible.
953 generics_entire_domain
954 If the genericstable is enabled and GENERICS_DOMAIN or
955 GENERICS_DOMAIN_FILE is used, this feature will cause
956 addresses to be searched in the map if their domain
957 parts are subdomains of elements in class {G}.
959 virtusertable A domain-specific form of aliasing, allowing multiple
960 virtual domains to be hosted on one machine. For example,
961 if the virtuser table contained:
963 info@foo.com foo-info
964 info@bar.com bar-info
965 joe@bar.com error:nouser 550 No such user here
966 jax@bar.com error:5.7.0:550 Address invalid
967 @baz.org jane@example.net
969 then mail addressed to info@foo.com will be sent to the
970 address foo-info, mail addressed to info@bar.com will be
971 delivered to bar-info, and mail addressed to anyone at baz.org
972 will be sent to jane@example.net, mail to joe@bar.com will
973 be rejected with the specified error message, and mail to
974 jax@bar.com will also have a RFC 1893 compliant error code
977 The username from the original address is passed
980 @foo.org %1@example.com
982 meaning someone@foo.org will be sent to someone@example.com.
983 Additionally, if the local part consists of "user+detail"
984 then "detail" is passed as %2 and "+detail" is passed as %3
985 when a match against user+* is attempted, so entries like
987 old+*@foo.org new+%2@example.com
988 gen+*@foo.org %2@example.com
989 +*@foo.org %1%3@example.com
990 X++@foo.org Z%3@example.com
993 and other forms are possible. Note: to preserve "+detail"
994 for a default case (@domain) %1%3 must be used as RHS.
995 There are two wildcards after "+": "+" matches only a non-empty
996 detail, "*" matches also empty details, e.g., user+@foo.org
997 matches +*@foo.org but not ++@foo.org. This can be used
998 to ensure that the parameters %2 and %3 are not empty.
1000 All the host names on the left hand side (foo.com, bar.com,
1001 and baz.org) must be in class {w} or class {VirtHost}. The
1002 latter can be defined by the macros VIRTUSER_DOMAIN or
1003 VIRTUSER_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1004 MASQUERADE_DOMAIN_FILE, see below). If VIRTUSER_DOMAIN or
1005 VIRTUSER_DOMAIN_FILE is used, then the entries of class
1006 {VirtHost} are added to class {R}, i.e., relaying is allowed
1007 to (and from) those domains. The default map definition is:
1009 hash /etc/mail/virtusertable
1011 A new definition can be specified as the second argument of
1012 the FEATURE macro, such as
1014 FEATURE(`virtusertable', `dbm /etc/mail/virtusers')
1016 virtuser_entire_domain
1017 If the virtusertable is enabled and VIRTUSER_DOMAIN or
1018 VIRTUSER_DOMAIN_FILE is used, this feature will cause
1019 addresses to be searched in the map if their domain
1020 parts are subdomains of elements in class {VirtHost}.
1022 ldap_routing Implement LDAP-based e-mail recipient routing according to
1023 the Internet Draft draft-lachman-laser-ldap-mail-routing-01.
1024 This provides a method to re-route addresses with a
1025 domain portion in class {LDAPRoute} to either a
1026 different mail host or a different address. Hosts can
1027 be added to this class using LDAPROUTE_DOMAIN and
1028 LDAPROUTE_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1029 MASQUERADE_DOMAIN_FILE, see below).
1031 See the LDAP ROUTING section below for more information.
1033 nodns If you aren't running DNS at your site (for example,
1034 you are UUCP-only connected). It's hard to consider
1035 this a "feature", but hey, it had to go somewhere.
1036 Actually, as of 8.7 this is a no-op -- remove "dns" from
1037 the hosts service switch entry instead.
1039 nullclient This is a special case -- it creates a configuration file
1040 containing nothing but support for forwarding all mail to a
1041 central hub via a local SMTP-based network. The argument
1042 is the name of that hub.
1044 The only other feature that should be used in conjunction
1045 with this one is FEATURE(`nocanonify'). No mailers
1046 should be defined. No aliasing or forwarding is done.
1048 local_lmtp Use an LMTP capable local mailer. The argument to this
1049 feature is the pathname of an LMTP capable mailer. By
1050 default, mail.local is used. This is expected to be the
1051 mail.local which came with the 8.9 distribution which is
1052 LMTP capable. The path to mail.local is set by the
1053 confEBINDIR m4 variable -- making the default
1054 LOCAL_MAILER_PATH /usr/libexec/mail.local.
1055 If a different LMTP capable mailer is used, its pathname
1056 can be specified as second parameter and the arguments
1057 passed to it (A=) as third parameter, e.g.,
1059 FEATURE(`local_lmtp', `/usr/local/bin/lmtp', `lmtp')
1061 WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
1062 i.e., without respecting any definitions in an OSTYPE setting.
1064 local_procmail Use procmail or another delivery agent as the local mailer.
1065 The argument to this feature is the pathname of the
1066 delivery agent, which defaults to PROCMAIL_MAILER_PATH.
1067 Note that this does NOT use PROCMAIL_MAILER_FLAGS or
1068 PROCMAIL_MAILER_ARGS for the local mailer; tweak
1069 LOCAL_MAILER_FLAGS and LOCAL_MAILER_ARGS instead, or
1070 specify the appropriate parameters. When procmail is used,
1071 the local mailer can make use of the
1072 "user+indicator@local.host" syntax; normally the +indicator
1073 is just tossed, but by default it is passed as the -a
1074 argument to procmail.
1076 This feature can take up to three arguments:
1078 1. Path to the mailer program
1079 [default: /usr/local/bin/procmail]
1080 2. Argument vector including name of the program
1081 [default: procmail -Y -a $h -d $u]
1082 3. Flags for the mailer [default: SPfhn9]
1084 Empty arguments cause the defaults to be taken.
1085 Note that if you are on a system with a broken
1086 setreuid() call, you may need to add -f $f to the procmail
1087 argument vector to pass the proper sender to procmail.
1089 For example, this allows it to use the maildrop
1090 (http://www.flounder.net/~mrsam/maildrop/) mailer instead
1093 FEATURE(`local_procmail', `/usr/local/bin/maildrop',
1098 FEATURE(`local_procmail', `/usr/local/bin/scanmails')
1100 WARNING: This feature sets LOCAL_MAILER_FLAGS unconditionally,
1101 i.e., without respecting any definitions in an OSTYPE setting.
1103 bestmx_is_local Accept mail as though locally addressed for any host that
1104 lists us as the best possible MX record. This generates
1105 additional DNS traffic, but should be OK for low to
1106 medium traffic hosts. The argument may be a set of
1107 domains, which will limit the feature to only apply to
1108 these domains -- this will reduce unnecessary DNS
1109 traffic. THIS FEATURE IS FUNDAMENTALLY INCOMPATIBLE WITH
1110 WILDCARD MX RECORDS!!! If you have a wildcard MX record
1111 that matches your domain, you cannot use this feature.
1113 smrsh Use the SendMail Restricted SHell (smrsh) provided
1114 with the distribution instead of /bin/sh for mailing
1115 to programs. This improves the ability of the local
1116 system administrator to control what gets run via
1117 e-mail. If an argument is provided it is used as the
1118 pathname to smrsh; otherwise, the path defined by
1119 confEBINDIR is used for the smrsh binary -- by default,
1120 /usr/libexec/smrsh is assumed.
1123 By default, the sendmail configuration files do not permit
1124 mail relaying (that is, accepting mail from outside your
1125 local host (class {w}) and sending it to another host than
1126 your local host). This option sets your site to allow
1127 mail relaying from any site to any site. In almost all
1128 cases, it is better to control relaying more carefully
1129 with the access map, class {R}, or authentication. Domains
1130 can be added to class {R} by the macros RELAY_DOMAIN or
1131 RELAY_DOMAIN_FILE (analogously to MASQUERADE_DOMAIN and
1132 MASQUERADE_DOMAIN_FILE, see below).
1135 This option allows any host in your domain as defined by
1136 class {m} to use your server for relaying. Notice: make
1137 sure that your domain is not just a top level domain,
1138 e.g., com. This can happen if you give your host a name
1139 like example.com instead of host.example.com.
1142 By default, names that are listed as RELAY in the access
1143 db and class {R} are treated as domain names, not host names.
1144 For example, if you specify ``foo.com'', then mail to or
1145 from foo.com, abc.foo.com, or a.very.deep.domain.foo.com
1146 will all be accepted for relaying. This feature changes
1147 the behaviour to lookup individual host names only.
1150 Turns on the ability to allow relaying based on the MX
1151 records of the host portion of an incoming recipient; that
1152 is, if an MX record for host foo.com points to your site,
1153 you will accept and relay mail addressed to foo.com. See
1154 description below for more information before using this
1155 feature. Also, see the KNOWNBUGS entry regarding bestmx
1158 FEATURE(`relay_based_on_MX') does not necessarily allow
1159 routing of these messages which you expect to be allowed,
1160 if route address syntax (or %-hack syntax) is used. If
1161 this is a problem, add entries to the access-table or use
1162 FEATURE(`loose_relay_check').
1165 Allows relaying if the mail sender is listed as RELAY in
1166 the access map. If an optional argument `domain' (this
1167 is the literal word `domain', not a placeholder) is given,
1168 relaying can be allowed just based on the domain portion
1169 of the sender address. This feature should only be used if
1170 absolutely necessary as the sender address can be easily
1171 forged. Use of this feature requires the "From:" tag to
1172 be used for the key in the access map; see the discussion
1173 of tags and FEATURE(`relay_mail_from') in the section on
1174 anti-spam configuration control.
1177 Allows relaying if the domain portion of the mail sender
1178 is a local host. This should only be used if absolutely
1179 necessary as it opens a window for spammers. Specifically,
1180 they can send mail to your mail server that claims to be
1181 from your domain (either directly or via a routed address),
1182 and you will go ahead and relay it out to arbitrary hosts
1185 accept_unqualified_senders
1186 Normally, MAIL FROM: commands in the SMTP session will be
1187 refused if the connection is a network connection and the
1188 sender address does not include a domain name. If your
1189 setup sends local mail unqualified (i.e., MAIL FROM: <joe>),
1190 you will need to use this feature to accept unqualified
1191 sender addresses. Setting the DaemonPortOptions modifier
1192 'u' overrides the default behavior, i.e., unqualified
1193 addresses are accepted even without this FEATURE.
1194 If this FEATURE is not used, the DaemonPortOptions modifier
1195 'f' can be used to enforce fully qualified addresses.
1197 accept_unresolvable_domains
1198 Normally, MAIL FROM: commands in the SMTP session will be
1199 refused if the host part of the argument to MAIL FROM:
1200 cannot be located in the host name service (e.g., an A or
1201 MX record in DNS). If you are inside a firewall that has
1202 only a limited view of the Internet host name space, this
1203 could cause problems. In this case you probably want to
1204 use this feature to accept all domains on input, even if
1205 they are unresolvable.
1207 access_db Turns on the access database feature. The access db gives
1208 you the ability to allow or refuse to accept mail from
1209 specified domains for administrative reasons. Moreover,
1210 it can control the behavior of sendmail in various situations.
1211 By default, the access database specification is:
1213 hash -T<TMPF> /etc/mail/access
1215 See the anti-spam configuration control section for further
1216 important information about this feature. Notice:
1217 "-T<TMPF>" is meant literal, do not replace it by anything.
1219 blacklist_recipients
1220 Turns on the ability to block incoming mail for certain
1221 recipient usernames, hostnames, or addresses. For
1222 example, you can block incoming mail to user nobody,
1223 host foo.mydomain.com, or guest@bar.mydomain.com.
1224 These specifications are put in the access db as
1225 described in the anti-spam configuration control section
1226 later in this document.
1228 delay_checks The rulesets check_mail and check_relay will not be called
1229 when a client connects or issues a MAIL command, respectively.
1230 Instead, those rulesets will be called by the check_rcpt
1231 ruleset; they will be skipped under certain circumstances.
1232 See "Delay all checks" in the anti-spam configuration control
1233 section. Note: this feature is incompatible to the versions
1236 use_client_ptr If this feature is enabled then check_relay will override
1237 its first argument with $&{client_ptr}. This is useful for
1238 rejections based on the unverified hostname of client,
1239 which turns on the same behavior as in earlier sendmail
1240 versions when delay_checks was not in use. See doc/op/op.*
1241 about check_relay, {client_name}, and {client_ptr}.
1243 dnsbl Turns on rejection of hosts found in an DNS based rejection
1244 list. If an argument is provided it is used as the domain
1245 in which blocked hosts are listed; otherwise it defaults to
1246 blackholes.mail-abuse.org. An explanation for an DNS based
1247 rejection list can be found at http://mail-abuse.org/rbl/.
1248 A second argument can be used to change the default error
1249 message. Without that second argument, the error message
1251 Rejected: IP-ADDRESS listed at SERVER
1252 where IP-ADDRESS and SERVER are replaced by the appropriate
1253 information. By default, temporary lookup failures are
1254 ignored. This behavior can be changed by specifying a
1255 third argument, which must be either `t' or a full error
1256 message. See the anti-spam configuration control section for
1257 an example. The dnsbl feature can be included several times
1258 to query different DNS based rejection lists. See also
1259 enhdnsbl for an enhanced version.
1261 Set the DNSBL_MAP mc option to change the default map
1262 definition from `host'. Set the DNSBL_MAP_OPT mc option
1263 to add additional options to the map specification used.
1265 Some DNS based rejection lists cause failures if asked
1266 for AAAA records. If your sendmail version is compiled
1267 with IPv6 support (NETINET6) and you experience this
1270 define(`DNSBL_MAP', `dns -R A')
1272 before the first use of this feature. Alternatively you
1273 can use enhdnsbl instead (see below). Moreover, this
1274 statement can be used to reduce the number of DNS retries,
1277 define(`DNSBL_MAP', `dns -R A -r2')
1279 See below (EDNSBL_TO) for an explanation.
1281 NOTE: The default DNS blacklist, blackholes.mail-abuse.org,
1282 is a service offered by the Mail Abuse Prevention System
1283 (MAPS). As of July 31, 2001, MAPS is a subscription
1284 service, so using that network address won't work if you
1285 haven't subscribed. Contact MAPS to subscribe
1286 (http://mail-abuse.org/).
1288 enhdnsbl Enhanced version of dnsbl (see above). Further arguments
1289 (up to 5) can be used to specify specific return values
1290 from lookups. Temporary lookup failures are ignored unless
1291 a third argument is given, which must be either `t' or a full
1292 error message. By default, any successful lookup will
1293 generate an error. Otherwise the result of the lookup is
1294 compared with the supplied argument(s), and only if a match
1295 occurs an error is generated. For example,
1297 FEATURE(`enhdnsbl', `dnsbl.example.com', `', `t', `127.0.0.2.')
1299 will reject the e-mail if the lookup returns the value
1300 ``127.0.0.2.'', or generate a 451 response if the lookup
1301 temporarily failed. The arguments can contain metasymbols
1302 as they are allowed in the LHS of rules. As the example
1303 shows, the default values are also used if an empty argument,
1304 i.e., `', is specified. This feature requires that sendmail
1305 has been compiled with the flag DNSMAP (see sendmail/README).
1307 Set the EDNSBL_TO mc option to change the DNS retry count
1308 from the default value of 5, this can be very useful when
1309 a DNS server is not responding, which in turn may cause
1310 clients to time out (an entry stating
1312 did not issue MAIL/EXPN/VRFY/ETRN
1316 ratecontrol Enable simple ruleset to do connection rate control
1317 checking. This requires entries in access_db of the form
1319 ClientRate:IP.ADD.RE.SS LIMIT
1321 The RHS specifies the maximum number of connections
1322 (an integer number) over the time interval defined
1323 by ConnectionRateWindowSize, where 0 means unlimited.
1325 Take the following example:
1327 ClientRate:10.1.2.3 4
1328 ClientRate:127.0.0.1 0
1331 10.1.2.3 can only make up to 4 connections, the
1332 general limit it 10, and 127.0.0.1 can make an unlimited
1333 number of connections per ConnectionRateWindowSize.
1335 See also CONNECTION CONTROL.
1337 conncontrol Enable a simple check of the number of incoming SMTP
1338 connections. This requires entries in access_db of the
1341 ClientConn:IP.ADD.RE.SS LIMIT
1343 The RHS specifies the maximum number of open connections
1344 (an integer number).
1346 Take the following example:
1348 ClientConn:10.1.2.3 4
1349 ClientConn:127.0.0.1 0
1352 10.1.2.3 can only have up to 4 open connections, the
1353 general limit it 10, and 127.0.0.1 does not have any
1356 See also CONNECTION CONTROL.
1358 mtamark Experimental support for "Marking Mail Transfer Agents in
1359 Reverse DNS with TXT RRs" (MTAMark), see
1360 draft-stumpf-dns-mtamark-01. Optional arguments are:
1362 1. Error message, default:
1364 550 Rejected: $&{client_addr} not listed as MTA
1366 2. Temporary lookup failures are ignored unless a second
1367 argument is given, which must be either `t' or a full
1370 3. Lookup prefix, default: _perm._smtp._srv. This should
1371 not be changed unless the draft changes it.
1375 FEATURE(`mtamark', `', `t')
1377 lookupdotdomain Look up also .domain in the access map. This allows to
1378 match only subdomains. It does not work well with
1379 FEATURE(`relay_hosts_only'), because most lookups for
1380 subdomains are suppressed by the latter feature.
1383 Normally, if % addressing is used for a recipient, e.g.
1384 user%site@othersite, and othersite is in class {R}, the
1385 check_rcpt ruleset will strip @othersite and recheck
1386 user@site for relaying. This feature changes that
1387 behavior. It should not be needed for most installations.
1389 authinfo Provide a separate map for client side authentication
1390 information. See SMTP AUTHENTICATION for details.
1391 By default, the authinfo database specification is:
1393 hash /etc/mail/authinfo
1396 Preserve the name of the recipient host if LUSER_RELAY is
1397 used. Without this option, the domain part of the
1398 recipient address will be replaced by the host specified as
1399 LUSER_RELAY. This feature only works if the hostname is
1400 passed to the mailer (see mailer triple in op.me). Note
1401 that in the default configuration the local mailer does not
1402 receive the hostname, i.e., the mailer triple has an empty
1405 preserve_local_plus_detail
1406 Preserve the +detail portion of the address when passing
1407 address to local delivery agent. Disables alias and
1408 .forward +detail stripping (e.g., given user+detail, only
1409 that address will be looked up in the alias file; user+* and
1410 user will not be looked up). Only use if the local
1411 delivery agent in use supports +detail addressing.
1413 compat_check Enable ruleset check_compat to look up pairs of addresses
1414 with the Compat: tag -- Compat:sender<@>recipient -- in the
1415 access map. Valid values for the RHS include
1416 DISCARD silently discard recipient
1417 TEMP: return a temporary error
1418 ERROR: return a permanent error
1419 In the last two cases, a 4xy/5xy SMTP reply code should
1422 no_default_msa Don't generate the default MSA daemon, i.e.,
1423 DAEMON_OPTIONS(`Port=587,Name=MSA,M=E')
1424 To define a MSA daemon with other parameters, use this
1425 FEATURE and introduce new settings via DAEMON_OPTIONS().
1427 msp Defines config file for Message Submission Program.
1428 See sendmail/SECURITY for details and cf/cf/submit.mc how
1429 to use it. An optional argument can be used to override
1430 the default of `[localhost]' to use as host to send all
1431 e-mails to. Note that MX records will be used if the
1432 specified hostname is not in square brackets (e.g.,
1433 [hostname]). If `MSA' is specified as second argument then
1434 port 587 is used to contact the server. Example:
1436 FEATURE(`msp', `', `MSA')
1438 Some more hints about possible changes can be found below
1439 in the section MESSAGE SUBMISSION PROGRAM.
1441 Note: Due to many problems, submit.mc uses
1443 FEATURE(`msp', `[127.0.0.1]')
1445 by default. If you have a machine with IPv6 only,
1448 FEATURE(`msp', `[IPv6:::1]')
1450 If you want to continue using '[localhost]', (the behavior
1455 queuegroup A simple example how to select a queue group based
1456 on the full e-mail address or the domain of the
1457 recipient. Selection is done via entries in the
1458 access map using the tag QGRP:, for example:
1460 QGRP:example.com main
1461 QGRP:friend@some.org others
1462 QGRP:my.domain local
1464 where "main", "others", and "local" are names of
1465 queue groups. If an argument is specified, it is used
1466 as default queue group.
1468 Note: please read the warning in doc/op/op.me about
1469 queue groups and possible queue manipulations.
1471 greet_pause Adds the greet_pause ruleset which enables open proxy
1472 and SMTP slamming protection. The feature can take an
1473 argument specifying the milliseconds to wait:
1475 FEATURE(`greet_pause', `5000') dnl 5 seconds
1477 If FEATURE(`access_db') is enabled, an access database
1478 lookup with the GreetPause tag is done using client
1479 hostname, domain, IP address, or subnet to determine the
1482 GreetPause:my.domain 0
1483 GreetPause:example.com 5000
1484 GreetPause:10.1.2 2000
1485 GreetPause:127.0.0.1 0
1487 When using FEATURE(`access_db'), the optional
1488 FEATURE(`greet_pause') argument becomes the default if
1489 nothing is found in the access database. A ruleset called
1490 Local_greet_pause can be used for local modifications, e.g.,
1494 R$* $: $&{daemon_flags}
1501 Some things just can't be called features. To make this clear,
1502 they go in the hack subdirectory and are referenced using the HACK
1503 macro. These will tend to be site-dependent. The release
1504 includes the Berkeley-dependent "cssubdomain" hack (that makes
1505 sendmail accept local names in either Berkeley.EDU or CS.Berkeley.EDU;
1506 this is intended as a short-term aid while moving hosts into
1510 +--------------------+
1511 | SITE CONFIGURATION |
1512 +--------------------+
1514 *****************************************************
1515 * This section is really obsolete, and is preserved *
1516 * only for back compatibility. You should plan on *
1517 * using mailertables for new installations. In *
1518 * particular, it doesn't work for the newer forms *
1519 * of UUCP mailers, such as uucp-uudom. *
1520 *****************************************************
1522 Complex sites will need more local configuration information, such as
1523 lists of UUCP hosts they speak with directly. This can get a bit more
1524 tricky. For an example of a "complex" site, see cf/ucbvax.mc.
1526 The SITECONFIG macro allows you to indirectly reference site-dependent
1527 configuration information stored in the siteconfig subdirectory. For
1530 SITECONFIG(`uucp.ucbvax', `ucbvax', `U')
1532 reads the file uucp.ucbvax for local connection information. The
1533 second parameter is the local name (in this case just "ucbvax" since
1534 it is locally connected, and hence a UUCP hostname). The third
1535 parameter is the name of both a macro to store the local name (in
1536 this case, {U}) and the name of the class (e.g., {U}) in which to store
1537 the host information read from the file. Another SITECONFIG line reads
1539 SITECONFIG(`uucp.ucbarpa', `ucbarpa.Berkeley.EDU', `W')
1541 This says that the file uucp.ucbarpa contains the list of UUCP sites
1542 connected to ucbarpa.Berkeley.EDU. Class {W} will be used to
1543 store this list, and $W is defined to be ucbarpa.Berkeley.EDU, that
1544 is, the name of the relay to which the hosts listed in uucp.ucbarpa
1545 are connected. [The machine ucbarpa is gone now, but this
1546 out-of-date configuration file has been left around to demonstrate
1547 how you might do this.]
1549 Note that the case of SITECONFIG with a third parameter of ``U'' is
1550 special; the second parameter is assumed to be the UUCP name of the
1551 local site, rather than the name of a remote site, and the UUCP name
1552 is entered into class {w} (the list of local hostnames) as $U.UUCP.
1554 The siteconfig file (e.g., siteconfig/uucp.ucbvax.m4) contains nothing
1555 more than a sequence of SITE macros describing connectivity. For
1561 The second example demonstrates that you can use two names on the
1562 same line; these are usually aliases for the same host (or are at
1563 least in the same company).
1565 The macro LOCAL_UUCP can be used to add rules into the generated
1566 cf file at the place where MAILER(`uucp') inserts its rules. This
1567 should only be used if really necessary.
1569 +--------------------+
1570 | USING UUCP MAILERS |
1571 +--------------------+
1573 It's hard to get UUCP mailers right because of the extremely ad hoc
1574 nature of UUCP addressing. These config files are really designed
1575 for domain-based addressing, even for UUCP sites.
1577 There are four UUCP mailers available. The choice of which one to
1578 use is partly a matter of local preferences and what is running at
1579 the other end of your UUCP connection. Unlike good protocols that
1580 define what will go over the wire, UUCP uses the policy that you
1581 should do what is right for the other end; if they change, you have
1582 to change. This makes it hard to do the right thing, and discourages
1583 people from updating their software. In general, if you can avoid
1586 The major choice is whether to go for a domainized scheme or a
1587 non-domainized scheme. This depends entirely on what the other
1588 end will recognize. If at all possible, you should encourage the
1589 other end to go to a domain-based system -- non-domainized addresses
1590 don't work entirely properly.
1592 The four mailers are:
1594 uucp-old (obsolete name: "uucp")
1595 This is the oldest, the worst (but the closest to UUCP) way of
1596 sending messages across UUCP connections. It does bangify
1597 everything and prepends $U (your UUCP name) to the sender's
1598 address (which can already be a bang path itself). It can
1599 only send to one address at a time, so it spends a lot of
1600 time copying duplicates of messages. Avoid this if at all
1603 uucp-new (obsolete name: "suucp")
1604 The same as above, except that it assumes that in one rmail
1605 command you can specify several recipients. It still has a
1606 lot of other problems.
1609 This UUCP mailer keeps everything as domain addresses.
1610 Basically, it uses the SMTP mailer rewriting rules. This mailer
1611 is only included if MAILER(`smtp') is specified before
1614 Unfortunately, a lot of UUCP mailer transport agents require
1615 bangified addresses in the envelope, although you can use
1616 domain-based addresses in the message header. (The envelope
1617 shows up as the From_ line on UNIX mail.) So....
1620 This is a cross between uucp-new (for the envelope addresses)
1621 and uucp-dom (for the header addresses). It bangifies the
1622 envelope sender (From_ line in messages) without adding the
1623 local hostname, unless there is no host name on the address
1624 at all (e.g., "wolf") or the host component is a UUCP host name
1625 instead of a domain name ("somehost!wolf" instead of
1626 "some.dom.ain!wolf"). This is also included only if MAILER(`smtp')
1627 is also specified earlier.
1631 On host grasp.insa-lyon.fr (UUCP host name "grasp"), the following
1632 summarizes the sender rewriting for various mailers.
1634 Mailer sender rewriting in the envelope
1635 ------ ------ -------------------------
1636 uucp-{old,new} wolf grasp!wolf
1637 uucp-dom wolf wolf@grasp.insa-lyon.fr
1638 uucp-uudom wolf grasp.insa-lyon.fr!wolf
1640 uucp-{old,new} wolf@fr.net grasp!fr.net!wolf
1641 uucp-dom wolf@fr.net wolf@fr.net
1642 uucp-uudom wolf@fr.net fr.net!wolf
1644 uucp-{old,new} somehost!wolf grasp!somehost!wolf
1645 uucp-dom somehost!wolf somehost!wolf@grasp.insa-lyon.fr
1646 uucp-uudom somehost!wolf grasp.insa-lyon.fr!somehost!wolf
1648 If you are using one of the domainized UUCP mailers, you really want
1649 to convert all UUCP addresses to domain format -- otherwise, it will
1650 do it for you (and probably not the way you expected). For example,
1651 if you have the address foo!bar!baz (and you are not sending to foo),
1652 the heuristics will add the @uucp.relay.name or @local.host.name to
1653 this address. However, if you map foo to foo.host.name first, it
1654 will not add the local hostname. You can do this using the uucpdomain
1658 +-------------------+
1659 | TWEAKING RULESETS |
1660 +-------------------+
1662 For more complex configurations, you can define special rules.
1663 The macro LOCAL_RULE_3 introduces rules that are used in canonicalizing
1664 the names. Any modifications made here are reflected in the header.
1666 A common use is to convert old UUCP addresses to SMTP addresses using
1667 the UUCPSMTP macro. For example:
1670 UUCPSMTP(`decvax', `decvax.dec.com')
1671 UUCPSMTP(`research', `research.att.com')
1673 will cause addresses of the form "decvax!user" and "research!user"
1674 to be converted to "user@decvax.dec.com" and "user@research.att.com"
1677 This could also be used to look up hosts in a database map:
1680 R$* < @ $+ > $* $: $1 < @ $(hostmap $2 $) > $3
1682 This map would be defined in the LOCAL_CONFIG portion, as shown below.
1684 Similarly, LOCAL_RULE_0 can be used to introduce new parsing rules.
1685 For example, new rules are needed to parse hostnames that you accept
1686 via MX records. For example, you might have:
1689 R$+ <@ host.dom.ain.> $#uucp $@ cnmat $: $1 < @ host.dom.ain.>
1691 You would use this if you had installed an MX record for cnmat.Berkeley.EDU
1692 pointing at this host; this rule catches the message and forwards it on
1695 You can also tweak rulesets 1 and 2 using LOCAL_RULE_1 and LOCAL_RULE_2.
1696 These rulesets are normally empty.
1698 A similar macro is LOCAL_CONFIG. This introduces lines added after the
1699 boilerplate option setting but before rulesets. Do not declare rulesets in
1700 the LOCAL_CONFIG section. It can be used to declare local database maps or
1701 whatever. For example:
1704 Khostmap hash /etc/mail/hostmap
1705 Kyplocal nis -m hosts.byname
1708 +---------------------------+
1709 | MASQUERADING AND RELAYING |
1710 +---------------------------+
1712 You can have your host masquerade as another using
1714 MASQUERADE_AS(`host.domain')
1716 This causes mail being sent to be labeled as coming from the
1717 indicated host.domain, rather than $j. One normally masquerades as
1718 one of one's own subdomains (for example, it's unlikely that
1719 Berkeley would choose to masquerade as an MIT site). This
1720 behaviour is modified by a plethora of FEATUREs; in particular, see
1721 masquerade_envelope, allmasquerade, limited_masquerade, and
1722 masquerade_entire_domain.
1724 The masquerade name is not normally canonified, so it is important
1725 that it be your One True Name, that is, fully qualified and not a
1726 CNAME. However, if you use a CNAME, the receiving side may canonify
1727 it for you, so don't think you can cheat CNAME mapping this way.
1729 Normally the only addresses that are masqueraded are those that come
1730 from this host (that is, are either unqualified or in class {w}, the list
1731 of local domain names). You can augment this list, which is realized
1734 MASQUERADE_DOMAIN(`otherhost.domain')
1736 The effect of this is that although mail to user@otherhost.domain
1737 will not be delivered locally, any mail including any user@otherhost.domain
1738 will, when relayed, be rewritten to have the MASQUERADE_AS address.
1739 This can be a space-separated list of names.
1741 If these names are in a file, you can use
1743 MASQUERADE_DOMAIN_FILE(`filename')
1745 to read the list of names from the indicated file (i.e., to add
1746 elements to class {M}).
1748 To exempt hosts or subdomains from being masqueraded, you can use
1750 MASQUERADE_EXCEPTION(`host.domain')
1752 This can come handy if you want to masquerade a whole domain
1753 except for one (or a few) host(s). If these names are in a file,
1756 MASQUERADE_EXCEPTION_FILE(`filename')
1758 Normally only header addresses are masqueraded. If you want to
1759 masquerade the envelope as well, use
1761 FEATURE(`masquerade_envelope')
1763 There are always users that need to be "exposed" -- that is, their
1764 internal site name should be displayed instead of the masquerade name.
1765 Root is an example (which has been "exposed" by default prior to 8.10).
1766 You can add users to this list using
1768 EXPOSED_USER(`usernames')
1770 This adds users to class {E}; you could also use
1772 EXPOSED_USER_FILE(`filename')
1774 You can also arrange to relay all unqualified names (that is, names
1775 without @host) to a relay host. For example, if you have a central
1776 email server, you might relay to that host so that users don't have
1777 to have .forward files or aliases. You can do this using
1779 define(`LOCAL_RELAY', `mailer:hostname')
1781 The ``mailer:'' can be omitted, in which case the mailer defaults to
1782 "relay". There are some user names that you don't want relayed, perhaps
1783 because of local aliases. A common example is root, which may be
1784 locally aliased. You can add entries to this list using
1786 LOCAL_USER(`usernames')
1788 This adds users to class {L}; you could also use
1790 LOCAL_USER_FILE(`filename')
1792 If you want all incoming mail sent to a centralized hub, as for a
1793 shared /var/spool/mail scheme, use
1795 define(`MAIL_HUB', `mailer:hostname')
1797 Again, ``mailer:'' defaults to "relay". If you define both LOCAL_RELAY
1798 and MAIL_HUB _AND_ you have FEATURE(`stickyhost'), unqualified names will
1799 be sent to the LOCAL_RELAY and other local names will be sent to MAIL_HUB.
1800 Note: there is a (long standing) bug which keeps this combination from
1801 working for addresses of the form user+detail.
1802 Names in class {L} will be delivered locally, so you MUST have aliases or
1803 .forward files for them.
1805 For example, if you are on machine mastodon.CS.Berkeley.EDU and you have
1806 FEATURE(`stickyhost'), the following combinations of settings will have the
1809 email sent to.... eric eric@mastodon.CS.Berkeley.EDU
1811 LOCAL_RELAY set to mail.CS.Berkeley.EDU (delivered locally)
1812 mail.CS.Berkeley.EDU (no local aliasing) (aliasing done)
1814 MAIL_HUB set to mammoth.CS.Berkeley.EDU mammoth.CS.Berkeley.EDU
1815 mammoth.CS.Berkeley.EDU (aliasing done) (aliasing done)
1817 Both LOCAL_RELAY and mail.CS.Berkeley.EDU mammoth.CS.Berkeley.EDU
1818 MAIL_HUB set as above (no local aliasing) (aliasing done)
1820 If you do not have FEATURE(`stickyhost') set, then LOCAL_RELAY and
1821 MAIL_HUB act identically, with MAIL_HUB taking precedence.
1823 If you want all outgoing mail to go to a central relay site, define
1824 SMART_HOST as well. Briefly:
1826 LOCAL_RELAY applies to unqualified names (e.g., "eric").
1827 MAIL_HUB applies to names qualified with the name of the
1828 local host (e.g., "eric@mastodon.CS.Berkeley.EDU").
1829 SMART_HOST applies to names qualified with other hosts or
1830 bracketed addresses (e.g., "eric@mastodon.CS.Berkeley.EDU"
1831 or "eric@[127.0.0.1]").
1833 However, beware that other relays (e.g., UUCP_RELAY, BITNET_RELAY,
1834 DECNET_RELAY, and FAX_RELAY) take precedence over SMART_HOST, so if you
1835 really want absolutely everything to go to a single central site you will
1836 need to unset all the other relays -- or better yet, find or build a
1837 minimal config file that does this.
1839 For duplicate suppression to work properly, the host name is best
1840 specified with a terminal dot:
1842 define(`MAIL_HUB', `host.domain.')
1843 note the trailing dot ---^
1846 +-------------------------------------------+
1847 | USING LDAP FOR ALIASES, MAPS, AND CLASSES |
1848 +-------------------------------------------+
1850 LDAP can be used for aliases, maps, and classes by either specifying your
1851 own LDAP map specification or using the built-in default LDAP map
1852 specification. The built-in default specifications all provide lookups
1853 which match against either the machine's fully qualified hostname (${j}) or
1854 a "cluster". The cluster allows you to share LDAP entries among a large
1855 number of machines without having to enter each of the machine names into
1856 each LDAP entry. To set the LDAP cluster name to use for a particular
1857 machine or set of machines, set the confLDAP_CLUSTER m4 variable to a
1858 unique name. For example:
1860 define(`confLDAP_CLUSTER', `Servers')
1862 Here, the word `Servers' will be the cluster name. As an example, assume
1863 that smtp.sendmail.org, etrn.sendmail.org, and mx.sendmail.org all belong
1864 to the Servers cluster.
1866 Some of the LDAP LDIF examples below show use of the Servers cluster.
1867 Every entry must have either a sendmailMTAHost or sendmailMTACluster
1868 attribute or it will be ignored. Be careful as mixing clusters and
1869 individual host records can have surprising results (see the CAUTION
1872 See the file cf/sendmail.schema for the actual LDAP schemas. Note that
1873 this schema (and therefore the lookups and examples below) is experimental
1874 at this point as it has had little public review. Therefore, it may change
1875 in future versions. Feedback via sendmail@sendmail.org is encouraged.
1881 The ALIAS_FILE (O AliasFile) option can be set to use LDAP for alias
1882 lookups. To use the default schema, simply use:
1884 define(`ALIAS_FILE', `ldap:')
1886 By doing so, you will use the default schema which expands to a map
1887 declared as follows:
1889 ldap -k (&(objectClass=sendmailMTAAliasObject)
1890 (sendmailMTAAliasGrouping=aliases)
1891 (|(sendmailMTACluster=${sendmailMTACluster})
1892 (sendmailMTAHost=$j))
1893 (sendmailMTAKey=%0))
1894 -v sendmailMTAAliasValue,sendmailMTAAliasSearch:FILTER:sendmailMTAAliasObject,sendmailMTAAliasURL:URL:sendmailMTAAliasObject
1897 NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
1898 used when the binary expands the `ldap:' token as the AliasFile option is
1899 not actually macro-expanded when read from the sendmail.cf file.
1901 Example LDAP LDIF entries might be:
1903 dn: sendmailMTAKey=sendmail-list, dc=sendmail, dc=org
1904 objectClass: sendmailMTA
1905 objectClass: sendmailMTAAlias
1906 objectClass: sendmailMTAAliasObject
1907 sendmailMTAAliasGrouping: aliases
1908 sendmailMTAHost: etrn.sendmail.org
1909 sendmailMTAKey: sendmail-list
1910 sendmailMTAAliasValue: ca@example.org
1911 sendmailMTAAliasValue: eric
1912 sendmailMTAAliasValue: gshapiro@example.com
1914 dn: sendmailMTAKey=owner-sendmail-list, dc=sendmail, dc=org
1915 objectClass: sendmailMTA
1916 objectClass: sendmailMTAAlias
1917 objectClass: sendmailMTAAliasObject
1918 sendmailMTAAliasGrouping: aliases
1919 sendmailMTAHost: etrn.sendmail.org
1920 sendmailMTAKey: owner-sendmail-list
1921 sendmailMTAAliasValue: eric
1923 dn: sendmailMTAKey=postmaster, dc=sendmail, dc=org
1924 objectClass: sendmailMTA
1925 objectClass: sendmailMTAAlias
1926 objectClass: sendmailMTAAliasObject
1927 sendmailMTAAliasGrouping: aliases
1928 sendmailMTACluster: Servers
1929 sendmailMTAKey: postmaster
1930 sendmailMTAAliasValue: eric
1932 Here, the aliases sendmail-list and owner-sendmail-list will be available
1933 only on etrn.sendmail.org but the postmaster alias will be available on
1934 every machine in the Servers cluster (including etrn.sendmail.org).
1936 CAUTION: aliases are additive so that entries like these:
1938 dn: sendmailMTAKey=bob, dc=sendmail, dc=org
1939 objectClass: sendmailMTA
1940 objectClass: sendmailMTAAlias
1941 objectClass: sendmailMTAAliasObject
1942 sendmailMTAAliasGrouping: aliases
1943 sendmailMTACluster: Servers
1945 sendmailMTAAliasValue: eric
1947 dn: sendmailMTAKey=bobetrn, dc=sendmail, dc=org
1948 objectClass: sendmailMTA
1949 objectClass: sendmailMTAAlias
1950 objectClass: sendmailMTAAliasObject
1951 sendmailMTAAliasGrouping: aliases
1952 sendmailMTAHost: etrn.sendmail.org
1954 sendmailMTAAliasValue: gshapiro
1956 would mean that on all of the hosts in the cluster, mail to bob would go to
1957 eric EXCEPT on etrn.sendmail.org in which case it would go to BOTH eric and
1960 If you prefer not to use the default LDAP schema for your aliases, you can
1961 specify the map parameters when setting ALIAS_FILE. For example:
1963 define(`ALIAS_FILE', `ldap:-k (&(objectClass=mailGroup)(mail=%0)) -v mgrpRFC822MailMember')
1969 FEATURE()'s which take an optional map definition argument (e.g., access,
1970 mailertable, virtusertable, etc.) can instead take the special keyword
1973 FEATURE(`access_db', `LDAP')
1974 FEATURE(`virtusertable', `LDAP')
1976 When this keyword is given, that map will use LDAP lookups consisting of
1977 the objectClass sendmailMTAClassObject, the attribute sendmailMTAMapName
1978 with the map name, a search attribute of sendmailMTAKey, and the value
1979 attribute sendmailMTAMapValue.
1981 The values for sendmailMTAMapName are:
1983 FEATURE() sendmailMTAMapName
1984 --------- ------------------
1989 genericstable generics
1991 uucpdomain uucpdomain
1992 virtusertable virtuser
1994 For example, FEATURE(`mailertable', `LDAP') would use the map definition:
1996 Kmailertable ldap -k (&(objectClass=sendmailMTAMapObject)
1997 (sendmailMTAMapName=mailer)
1998 (|(sendmailMTACluster=${sendmailMTACluster})
1999 (sendmailMTAHost=$j))
2000 (sendmailMTAKey=%0))
2001 -1 -v sendmailMTAMapValue,sendmailMTAMapSearch:FILTER:sendmailMTAMapObject,sendmailMTAMapURL:URL:sendmailMTAMapObject
2003 An example LDAP LDIF entry using this map might be:
2005 dn: sendmailMTAMapName=mailer, dc=sendmail, dc=org
2006 objectClass: sendmailMTA
2007 objectClass: sendmailMTAMap
2008 sendmailMTACluster: Servers
2009 sendmailMTAMapName: mailer
2011 dn: sendmailMTAKey=example.com, sendmailMTAMapName=mailer, dc=sendmail, dc=org
2012 objectClass: sendmailMTA
2013 objectClass: sendmailMTAMap
2014 objectClass: sendmailMTAMapObject
2015 sendmailMTAMapName: mailer
2016 sendmailMTACluster: Servers
2017 sendmailMTAKey: example.com
2018 sendmailMTAMapValue: relay:[smtp.example.com]
2020 CAUTION: If your LDAP database contains the record above and *ALSO* a host
2021 specific record such as:
2023 dn: sendmailMTAKey=example.com@etrn, sendmailMTAMapName=mailer, dc=sendmail, dc=org
2024 objectClass: sendmailMTA
2025 objectClass: sendmailMTAMap
2026 objectClass: sendmailMTAMapObject
2027 sendmailMTAMapName: mailer
2028 sendmailMTAHost: etrn.sendmail.org
2029 sendmailMTAKey: example.com
2030 sendmailMTAMapValue: relay:[mx.example.com]
2032 then these entries will give unexpected results. When the lookup is done
2033 on etrn.sendmail.org, the effect is that there is *NO* match at all as maps
2034 require a single match. Since the host etrn.sendmail.org is also in the
2035 Servers cluster, LDAP would return two answers for the example.com map key
2036 in which case sendmail would treat this as no match at all.
2038 If you prefer not to use the default LDAP schema for your maps, you can
2039 specify the map parameters when using the FEATURE(). For example:
2041 FEATURE(`access_db', `ldap:-1 -k (&(objectClass=mapDatabase)(key=%0)) -v value')
2047 Normally, classes can be filled via files or programs. As of 8.12, they
2048 can also be filled via map lookups using a new syntax:
2050 F{ClassName}mapkey@mapclass:mapspec
2052 mapkey is optional and if not provided the map key will be empty. This can
2053 be used with LDAP to read classes from LDAP. Note that the lookup is only
2054 done when sendmail is initially started. Use the special value `@LDAP' to
2055 use the default LDAP schema. For example:
2057 RELAY_DOMAIN_FILE(`@LDAP')
2059 would put all of the attribute sendmailMTAClassValue values of LDAP records
2060 with objectClass sendmailMTAClass and an attribute sendmailMTAClassName of
2061 'R' into class $={R}. In other words, it is equivalent to the LDAP map
2064 F{R}@ldap:-k (&(objectClass=sendmailMTAClass)
2065 (sendmailMTAClassName=R)
2066 (|(sendmailMTACluster=${sendmailMTACluster})
2067 (sendmailMTAHost=$j)))
2068 -v sendmailMTAClassValue,sendmailMTAClassSearch:FILTER:sendmailMTAClass,sendmailMTAClassURL:URL:sendmailMTAClass
2070 NOTE: The macros shown above ${sendmailMTACluster} and $j are not actually
2071 used when the binary expands the `@LDAP' token as class declarations are
2072 not actually macro-expanded when read from the sendmail.cf file.
2074 This can be used with class related commands such as RELAY_DOMAIN_FILE(),
2075 MASQUERADE_DOMAIN_FILE(), etc:
2077 Command sendmailMTAClassName
2078 ------- --------------------
2079 CANONIFY_DOMAIN_FILE() Canonify
2080 EXPOSED_USER_FILE() E
2081 GENERICS_DOMAIN_FILE() G
2082 LDAPROUTE_DOMAIN_FILE() LDAPRoute
2083 LDAPROUTE_EQUIVALENT_FILE() LDAPRouteEquiv
2085 MASQUERADE_DOMAIN_FILE() M
2086 MASQUERADE_EXCEPTION_FILE() N
2087 RELAY_DOMAIN_FILE() R
2088 VIRTUSER_DOMAIN_FILE() VirtHost
2090 You can also add your own as any 'F'ile class of the form:
2094 will use "ClassName" for the sendmailMTAClassName.
2096 An example LDAP LDIF entry would look like:
2098 dn: sendmailMTAClassName=R, dc=sendmail, dc=org
2099 objectClass: sendmailMTA
2100 objectClass: sendmailMTAClass
2101 sendmailMTACluster: Servers
2102 sendmailMTAClassName: R
2103 sendmailMTAClassValue: sendmail.org
2104 sendmailMTAClassValue: example.com
2105 sendmailMTAClassValue: 10.56.23
2107 CAUTION: If your LDAP database contains the record above and *ALSO* a host
2108 specific record such as:
2110 dn: sendmailMTAClassName=R@etrn.sendmail.org, dc=sendmail, dc=org
2111 objectClass: sendmailMTA
2112 objectClass: sendmailMTAClass
2113 sendmailMTAHost: etrn.sendmail.org
2114 sendmailMTAClassName: R
2115 sendmailMTAClassValue: example.com
2117 the result will be similar to the aliases caution above. When the lookup
2118 is done on etrn.sendmail.org, $={R} would contain all of the entries (from
2119 both the cluster match and the host match). In other words, the effective
2122 If you prefer not to use the default LDAP schema for your classes, you can
2123 specify the map parameters when using the class command. For example:
2125 VIRTUSER_DOMAIN_FILE(`@ldap:-k (&(objectClass=virtHosts)(host=*)) -v host')
2127 Remember, macros can not be used in a class declaration as the binary does
2135 FEATURE(`ldap_routing') can be used to implement the IETF Internet Draft
2136 LDAP Schema for Intranet Mail Routing
2137 (draft-lachman-laser-ldap-mail-routing-01). This feature enables
2138 LDAP-based rerouting of a particular address to either a different host
2139 or a different address. The LDAP lookup is first attempted on the full
2140 address (e.g., user@example.com) and then on the domain portion
2141 (e.g., @example.com). Be sure to setup your domain for LDAP routing using
2142 LDAPROUTE_DOMAIN(), e.g.:
2144 LDAPROUTE_DOMAIN(`example.com')
2146 Additionally, you can specify equivalent domains for LDAP routing using
2147 LDAPROUTE_EQUIVALENT() and LDAPROUTE_EQUIVALENT_FILE(). 'Equivalent'
2148 hostnames are mapped to $M (the masqueraded hostname for the server) before
2149 the LDAP query. For example, if the mail is addressed to
2150 user@host1.example.com, normally the LDAP lookup would only be done for
2151 'user@host1.example.com' and '@host1.example.com'. However, if
2152 LDAPROUTE_EQUIVALENT(`host1.example.com') is used, the lookups would also be
2153 done on 'user@example.com' and '@example.com' after attempting the
2154 host1.example.com lookups.
2156 By default, the feature will use the schemas as specified in the draft
2157 and will not reject addresses not found by the LDAP lookup. However,
2158 this behavior can be changed by giving additional arguments to the FEATURE()
2161 FEATURE(`ldap_routing', <mailHost>, <mailRoutingAddress>, <bounce>,
2162 <detail>, <nodomain>, <tempfail>)
2164 where <mailHost> is a map definition describing how to lookup an alternative
2165 mail host for a particular address; <mailRoutingAddress> is a map definition
2166 describing how to lookup an alternative address for a particular address;
2167 the <bounce> argument, if present and not the word "passthru", dictates
2168 that mail should be bounced if neither a mailHost nor mailRoutingAddress
2169 is found, if set to "sendertoo", the sender will be rejected if not
2170 found in LDAP; and <detail> indicates what actions to take if the address
2171 contains +detail information -- `strip' tries the lookup with the +detail
2172 and if no matches are found, strips the +detail and tries the lookup again;
2173 `preserve', does the same as `strip' but if a mailRoutingAddress match is
2174 found, the +detail information is copied to the new address; the <nodomain>
2175 argument, if present, will prevent the @domain lookup if the full
2176 address is not found in LDAP; the <tempfail> argument, if set to
2177 "tempfail", instructs the rules to give an SMTP 4XX temporary
2178 error if the LDAP server gives the MTA a temporary failure, or if set to
2179 "queue" (the default), the MTA will locally queue the mail.
2181 The default <mailHost> map definition is:
2183 ldap -1 -T<TMPF> -v mailHost -k (&(objectClass=inetLocalMailRecipient)
2184 (mailLocalAddress=%0))
2186 The default <mailRoutingAddress> map definition is:
2188 ldap -1 -T<TMPF> -v mailRoutingAddress
2189 -k (&(objectClass=inetLocalMailRecipient)
2190 (mailLocalAddress=%0))
2192 Note that neither includes the LDAP server hostname (-h server) or base DN
2193 (-b o=org,c=COUNTRY), both necessary for LDAP queries. It is presumed that
2194 your .mc file contains a setting for the confLDAP_DEFAULT_SPEC option with
2195 these settings. If this is not the case, the map definitions should be
2196 changed as described above. The "-T<TMPF>" is required in any user
2197 specified map definition to catch temporary errors.
2199 The following possibilities exist as a result of an LDAP lookup on an
2202 mailHost is mailRoutingAddress is Results in
2203 ----------- --------------------- ----------
2204 set to a set mail delivered to
2205 "local" host mailRoutingAddress
2207 set to a not set delivered to
2208 "local" host original address
2210 set to a set mailRoutingAddress
2211 remote host relayed to mailHost
2213 set to a not set original address
2214 remote host relayed to mailHost
2216 not set set mail delivered to
2219 not set not set delivered to
2220 original address *OR*
2221 bounced as unknown user
2223 The term "local" host above means the host specified is in class {w}. If
2224 the result would mean sending the mail to a different host, that host is
2225 looked up in the mailertable before delivery.
2227 Note that the last case depends on whether the third argument is given
2228 to the FEATURE() command. The default is to deliver the message to the
2231 The LDAP entries should be set up with an objectClass of
2232 inetLocalMailRecipient and the address be listed in a mailLocalAddress
2233 attribute. If present, there must be only one mailHost attribute and it
2234 must contain a fully qualified host name as its value. Similarly, if
2235 present, there must be only one mailRoutingAddress attribute and it must
2236 contain an RFC 822 compliant address. Some example LDAP records (in LDIF
2239 dn: uid=tom, o=example.com, c=US
2240 objectClass: inetLocalMailRecipient
2241 mailLocalAddress: tom@example.com
2242 mailRoutingAddress: thomas@mailhost.example.com
2244 This would deliver mail for tom@example.com to thomas@mailhost.example.com.
2246 dn: uid=dick, o=example.com, c=US
2247 objectClass: inetLocalMailRecipient
2248 mailLocalAddress: dick@example.com
2249 mailHost: eng.example.com
2251 This would relay mail for dick@example.com to the same address but redirect
2252 the mail to MX records listed for the host eng.example.com (unless the
2253 mailertable overrides).
2255 dn: uid=harry, o=example.com, c=US
2256 objectClass: inetLocalMailRecipient
2257 mailLocalAddress: harry@example.com
2258 mailHost: mktmail.example.com
2259 mailRoutingAddress: harry@mkt.example.com
2261 This would relay mail for harry@example.com to the MX records listed for
2262 the host mktmail.example.com using the new address harry@mkt.example.com
2263 when talking to that host.
2265 dn: uid=virtual.example.com, o=example.com, c=US
2266 objectClass: inetLocalMailRecipient
2267 mailLocalAddress: @virtual.example.com
2268 mailHost: server.example.com
2269 mailRoutingAddress: virtual@example.com
2271 This would send all mail destined for any username @virtual.example.com to
2272 the machine server.example.com's MX servers and deliver to the address
2273 virtual@example.com on that relay machine.
2276 +---------------------------------+
2277 | ANTI-SPAM CONFIGURATION CONTROL |
2278 +---------------------------------+
2280 The primary anti-spam features available in sendmail are:
2282 * Relaying is denied by default.
2283 * Better checking on sender information.
2287 Relaying (transmission of messages from a site outside your host (class
2288 {w}) to another site except yours) is denied by default. Note that this
2289 changed in sendmail 8.9; previous versions allowed relaying by default.
2290 If you really want to revert to the old behaviour, you will need to use
2291 FEATURE(`promiscuous_relay'). You can allow certain domains to relay
2292 through your server by adding their domain name or IP address to class
2293 {R} using RELAY_DOMAIN() and RELAY_DOMAIN_FILE() or via the access database
2294 (described below). Note that IPv6 addresses must be prefaced with "IPv6:".
2295 The file consists (like any other file based class) of entries listed on
2296 separate lines, e.g.,
2301 IPv6:2002:c0a8:51d2::23f4
2305 Notice: the last entry allows relaying for connections via a UNIX
2306 socket to the MTA/MSP. This might be necessary if your configuration
2307 doesn't allow relaying by other means in that case, e.g., by having
2308 localhost.$m in class {R} (make sure $m is not just a top level
2313 FEATURE(`relay_entire_domain')
2315 then any host in any of your local domains (that is, class {m})
2316 will be relayed (that is, you will accept mail either to or from any
2317 host in your domain).
2319 You can also allow relaying based on the MX records of the host
2320 portion of an incoming recipient address by using
2322 FEATURE(`relay_based_on_MX')
2324 For example, if your server receives a recipient of user@domain.com
2325 and domain.com lists your server in its MX records, the mail will be
2326 accepted for relay to domain.com. This feature may cause problems
2327 if MX lookups for the recipient domain are slow or time out. In that
2328 case, mail will be temporarily rejected. It is usually better to
2329 maintain a list of hosts/domains for which the server acts as relay.
2330 Note also that this feature will stop spammers from using your host
2331 to relay spam but it will not stop outsiders from using your server
2332 as a relay for their site (that is, they set up an MX record pointing
2333 to your mail server, and you will relay mail addressed to them
2334 without any prior arrangement). Along the same lines,
2336 FEATURE(`relay_local_from')
2338 will allow relaying if the sender specifies a return path (i.e.
2339 MAIL FROM: <user@domain>) domain which is a local domain. This is a
2340 dangerous feature as it will allow spammers to spam using your mail
2341 server by simply specifying a return address of user@your.domain.com.
2342 It should not be used unless absolutely necessary.
2343 A slightly better solution is
2345 FEATURE(`relay_mail_from')
2347 which allows relaying if the mail sender is listed as RELAY in the
2348 access map. If an optional argument `domain' (this is the literal
2349 word `domain', not a placeholder) is given, the domain portion of
2350 the mail sender is also checked to allowing relaying. This option
2351 only works together with the tag From: for the LHS of the access
2352 map entries. This feature allows spammers to abuse your mail server
2353 by specifying a return address that you enabled in your access file.
2354 This may be harder to figure out for spammers, but it should not
2355 be used unless necessary. Instead use SMTP AUTH or STARTTLS to
2356 allow relaying for roaming users.
2359 If source routing is used in the recipient address (e.g.,
2360 RCPT TO: <user%site.com@othersite.com>), sendmail will check
2361 user@site.com for relaying if othersite.com is an allowed relay host
2362 in either class {R}, class {m} if FEATURE(`relay_entire_domain') is used,
2363 or the access database if FEATURE(`access_db') is used. To prevent
2364 the address from being stripped down, use:
2366 FEATURE(`loose_relay_check')
2368 If you think you need to use this feature, you probably do not. This
2369 should only be used for sites which have no control over the addresses
2370 that they provide a gateway for. Use this FEATURE with caution as it
2371 can allow spammers to relay through your server if not setup properly.
2373 NOTICE: It is possible to relay mail through a system which the anti-relay
2374 rules do not prevent: the case of a system that does use FEATURE(`nouucp',
2375 `nospecial') (system A) and relays local messages to a mail hub (e.g., via
2376 LOCAL_RELAY or LUSER_RELAY) (system B). If system B doesn't use
2377 FEATURE(`nouucp') at all, addresses of the form
2378 <example.net!user@local.host> would be relayed to <user@example.net>.
2379 System A doesn't recognize `!' as an address separator and therefore
2380 forwards it to the mail hub which in turns relays it because it came from
2381 a trusted local host. So if a mailserver allows UUCP (bang-format)
2382 addresses, all systems from which it allows relaying should do the same
2383 or reject those addresses.
2385 As of 8.9, sendmail will refuse mail if the MAIL FROM: parameter has
2386 an unresolvable domain (i.e., one that DNS, your local name service,
2387 or special case rules in ruleset 3 cannot locate). This also applies
2388 to addresses that use domain literals, e.g., <user@[1.2.3.4]>, if the
2389 IP address can't be mapped to a host name. If you want to continue
2390 to accept such domains, e.g., because you are inside a firewall that
2391 has only a limited view of the Internet host name space (note that you
2392 will not be able to return mail to them unless you have some "smart
2393 host" forwarder), use
2395 FEATURE(`accept_unresolvable_domains')
2397 Alternatively, you can allow specific addresses by adding them to
2398 the access map, e.g.,
2400 From:unresolvable.domain OK
2404 Notice: domains which are temporarily unresolvable are (temporarily)
2405 rejected with a 451 reply code. If those domains should be accepted
2406 (which is discouraged) then you can use
2411 sendmail will also refuse mail if the MAIL FROM: parameter is not
2412 fully qualified (i.e., contains a domain as well as a user). If you
2413 want to continue to accept such senders, use
2415 FEATURE(`accept_unqualified_senders')
2417 Setting the DaemonPortOptions modifier 'u' overrides the default behavior,
2418 i.e., unqualified addresses are accepted even without this FEATURE. If
2419 this FEATURE is not used, the DaemonPortOptions modifier 'f' can be used
2420 to enforce fully qualified domain names.
2422 An ``access'' database can be created to accept or reject mail from
2423 selected domains. For example, you may choose to reject all mail
2424 originating from known spammers. To enable such a database, use
2426 FEATURE(`access_db')
2428 Notice: the access database is applied to the envelope addresses
2429 and the connection information, not to the header.
2431 The FEATURE macro can accept as second parameter the key file
2432 definition for the database; for example
2434 FEATURE(`access_db', `hash -T<TMPF> /etc/mail/access_map')
2436 Notice: If a second argument is specified it must contain the option
2437 `-T<TMPF>' as shown above. The optional third and fourth parameters
2438 may be `skip' or `lookupdotdomain'. The former enables SKIP as
2439 value part (see below), the latter is another way to enable the
2440 feature of the same name (see above).
2442 Remember, since /etc/mail/access is a database, after creating the text
2443 file as described below, you must use makemap to create the database
2446 makemap hash /etc/mail/access < /etc/mail/access
2448 The table itself uses e-mail addresses, domain names, and network
2449 numbers as keys. Note that IPv6 addresses must be prefaced with "IPv6:".
2452 From:spammer@aol.com REJECT
2453 From:cyberspammer.com REJECT
2454 Connect:cyberspammer.com REJECT
2456 Connect:192.168.212 REJECT
2457 Connect:IPv6:2002:c0a8:02c7 RELAY
2458 Connect:IPv6:2002:c0a8:51d2::23f4 REJECT
2460 would refuse mail from spammer@aol.com, any user from cyberspammer.com
2461 (or any host within the cyberspammer.com domain), any host in the entire
2462 top level domain TLD, 192.168.212.* network, and the IPv6 address
2463 2002:c0a8:51d2::23f4. It would allow relay for the IPv6 network
2464 2002:c0a8:02c7::/48.
2466 Entries in the access map should be tagged according to their type.
2467 Three tags are available:
2469 Connect: connection information (${client_addr}, ${client_name})
2470 From: envelope sender
2471 To: envelope recipient
2473 Notice: untagged entries are deprecated.
2475 If the required item is looked up in a map, it will be tried first
2476 with the corresponding tag in front, then (as fallback to enable
2477 backward compatibility) without any tag, unless the specific feature
2478 requires a tag. For example,
2480 From:spammer@some.dom REJECT
2481 To:friend.domain RELAY
2482 Connect:friend.domain OK
2483 Connect:from.domain RELAY
2484 From:good@another.dom OK
2485 From:another.dom REJECT
2487 This would deny mails from spammer@some.dom but you could still
2488 send mail to that address even if FEATURE(`blacklist_recipients')
2489 is enabled. Your system will allow relaying to friend.domain, but
2490 not from it (unless enabled by other means). Connections from that
2491 domain will be allowed even if it ends up in one of the DNS based
2492 rejection lists. Relaying is enabled from from.domain but not to
2493 it (since relaying is based on the connection information for
2494 outgoing relaying, the tag Connect: must be used; for incoming
2495 relaying, which is based on the recipient address, To: must be
2496 used). The last two entries allow mails from good@another.dom but
2497 reject mail from all other addresses with another.dom as domain
2501 The value part of the map can contain:
2503 OK Accept mail even if other rules in the running
2504 ruleset would reject it, for example, if the domain
2505 name is unresolvable. "Accept" does not mean
2506 "relay", but at most acceptance for local
2507 recipients. That is, OK allows less than RELAY.
2508 RELAY Accept mail addressed to the indicated domain or
2509 received from the indicated domain for relaying
2510 through your SMTP server. RELAY also serves as
2511 an implicit OK for the other checks.
2512 REJECT Reject the sender or recipient with a general
2514 DISCARD Discard the message completely using the
2515 $#discard mailer. If it is used in check_compat,
2516 it affects only the designated recipient, not
2517 the whole message as it does in all other cases.
2518 This should only be used if really necessary.
2519 SKIP This can only be used for host/domain names
2520 and IP addresses/nets. It will abort the current
2521 search for this entry without accepting or rejecting
2522 it but causing the default action.
2523 ### any text where ### is an RFC 821 compliant error code and
2524 "any text" is a message to return for the command.
2525 The string should be quoted to avoid surprises,
2526 e.g., sendmail may remove spaces otherwise.
2527 This type is deprecated, use one of the two
2528 ERROR: entries below instead.
2530 as above, but useful to mark error messages as such.
2531 ERROR:D.S.N:### any text
2532 where D.S.N is an RFC 1893 compliant error code
2533 and the rest as above.
2535 Quarantine the message using the given text as the
2536 quarantining reason.
2540 From:cyberspammer.com ERROR:"550 We don't accept mail from spammers"
2541 From:okay.cyberspammer.com OK
2542 Connect:sendmail.org RELAY
2543 To:sendmail.org RELAY
2544 Connect:128.32 RELAY
2545 Connect:128.32.2 SKIP
2546 Connect:IPv6:1:2:3:4:5:6:7 RELAY
2547 Connect:suspicious.example.com QUARANTINE:Mail from suspicious host
2548 Connect:[127.0.0.3] OK
2549 Connect:[IPv6:1:2:3:4:5:6:7:8] OK
2551 would accept mail from okay.cyberspammer.com, but would reject mail
2552 from all other hosts at cyberspammer.com with the indicated message.
2553 It would allow relaying mail from and to any hosts in the sendmail.org
2554 domain, and allow relaying from the IPv6 1:2:3:4:5:6:7:* network
2555 and from the 128.32.*.* network except for the 128.32.2.* network,
2556 which shows how SKIP is useful to exempt subnets/subdomains. The
2557 last two entries are for checks against ${client_name} if the IP
2558 address doesn't resolve to a hostname (or is considered as "may be
2559 forged"). That is, using square brackets means these are host
2560 names, not network numbers.
2562 Warning: if you change the RFC 821 compliant error code from the default
2563 value of 550, then you should probably also change the RFC 1893 compliant
2564 error code to match it. For example, if you use
2566 To:user@example.com ERROR:450 mailbox full
2568 the error returned would be "450 5.0.0 mailbox full" which is wrong.
2569 Use "ERROR:4.2.2:450 mailbox full" instead.
2571 Note, UUCP users may need to add hostname.UUCP to the access database
2576 FEATURE(`relay_hosts_only')
2578 then the above example will allow relaying for sendmail.org, but not
2579 hosts within the sendmail.org domain. Note that this will also require
2580 hosts listed in class {R} to be fully qualified host names.
2582 You can also use the access database to block sender addresses based on
2583 the username portion of the address. For example:
2585 From:FREE.STEALTH.MAILER@ ERROR:550 Spam not accepted
2587 Note that you must include the @ after the username to signify that
2588 this database entry is for checking only the username portion of the
2593 FEATURE(`blacklist_recipients')
2595 then you can add entries to the map for local users, hosts in your
2596 domains, or addresses in your domain which should not receive mail:
2598 To:badlocaluser@ ERROR:550 Mailbox disabled for badlocaluser
2599 To:host.my.TLD ERROR:550 That host does not accept mail
2600 To:user@other.my.TLD ERROR:550 Mailbox disabled for this recipient
2602 This would prevent a recipient of badlocaluser in any of the local
2603 domains (class {w}), any user at host.my.TLD, and the single address
2604 user@other.my.TLD from receiving mail. Please note: a local username
2605 must be now tagged with an @ (this is consistent with the check of
2606 the sender address, and hence it is possible to distinguish between
2607 hostnames and usernames). Enabling this feature will keep you from
2608 sending mails to all addresses that have an error message or REJECT
2609 as value part in the access map. Taking the example from above:
2611 spammer@aol.com REJECT
2612 cyberspammer.com REJECT
2614 Mail can't be sent to spammer@aol.com or anyone at cyberspammer.com.
2615 That's why tagged entries should be used.
2617 There are several DNS based blacklists, the first of which was
2618 the RBL (``Realtime Blackhole List'') run by the MAPS project,
2619 see http://mail-abuse.org/. These are databases of spammers
2620 maintained in DNS. To use such a database, specify
2624 This will cause sendmail to reject mail from any site in the original
2625 Realtime Blackhole List database. This default DNS blacklist,
2626 blackholes.mail-abuse.org, is a service offered by the Mail Abuse
2627 Prevention System (MAPS). As of July 31, 2001, MAPS is a subscription
2628 service, so using that network address won't work if you haven't
2629 subscribed. Contact MAPS to subscribe (http://mail-abuse.org/).
2631 You can specify an alternative RBL server to check by specifying an
2632 argument to the FEATURE. The default error message is
2634 Rejected: IP-ADDRESS listed at SERVER
2636 where IP-ADDRESS and SERVER are replaced by the appropriate
2637 information. A second argument can be used to specify a different
2638 text. By default, temporary lookup failures are ignored and hence
2639 cause the connection not to be rejected by the DNS based rejection
2640 list. This behavior can be changed by specifying a third argument,
2641 which must be either `t' or a full error message. For example:
2643 FEATURE(`dnsbl', `dnsbl.example.com', `',
2644 `"451 Temporary lookup failure for " $&{client_addr} " in dnsbl.example.com"')
2646 If `t' is used, the error message is:
2648 451 Temporary lookup failure of IP-ADDRESS at SERVER
2650 where IP-ADDRESS and SERVER are replaced by the appropriate
2653 This FEATURE can be included several times to query different
2654 DNS based rejection lists, e.g., the dial-up user list (see
2655 http://mail-abuse.org/dul/).
2657 Notice: to avoid checking your own local domains against those
2658 blacklists, use the access_db feature and add:
2661 Connect:127.0.0.1 RELAY
2663 to the access map, where 10.1 is your local network. You may
2664 want to use "RELAY" instead of "OK" to allow also relaying
2665 instead of just disabling the DNS lookups in the blacklists.
2668 The features described above make use of the check_relay, check_mail,
2669 and check_rcpt rulesets. Note that check_relay checks the SMTP
2670 client hostname and IP address when the connection is made to your
2671 server. It does not check if a mail message is being relayed to
2672 another server. That check is done in check_rcpt. If you wish to
2673 include your own checks, you can put your checks in the rulesets
2674 Local_check_relay, Local_check_mail, and Local_check_rcpt. For
2675 example if you wanted to block senders with all numeric usernames
2676 (i.e. 2312343@bigisp.com), you would use Local_check_mail and the
2680 Kallnumbers regex -a@MATCH ^[0-9]+$
2684 # check address against various regex checks
2685 R$* $: $>Parse0 $>3 $1
2686 R$+ < @ bigisp.com. > $* $: $(allnumbers $1 $)
2687 R@MATCH $#error $: 553 Header Error
2689 These rules are called with the original arguments of the corresponding
2690 check_* ruleset. If the local ruleset returns $#OK, no further checking
2691 is done by the features described above and the mail is accepted. If
2692 the local ruleset resolves to a mailer (such as $#error or $#discard),
2693 the appropriate action is taken. Other results starting with $# are
2694 interpreted by sendmail and may lead to unspecified behavior. Note: do
2695 NOT create a mailer with the name OK. Return values that do not start
2696 with $# are ignored, i.e., normal processing continues.
2701 By using FEATURE(`delay_checks') the rulesets check_mail and check_relay
2702 will not be called when a client connects or issues a MAIL command,
2703 respectively. Instead, those rulesets will be called by the check_rcpt
2704 ruleset; they will be skipped if a sender has been authenticated using
2705 a "trusted" mechanism, i.e., one that is defined via TRUST_AUTH_MECH().
2706 If check_mail returns an error then the RCPT TO command will be rejected
2707 with that error. If it returns some other result starting with $# then
2708 check_relay will be skipped. If the sender address (or a part of it) is
2709 listed in the access map and it has a RHS of OK or RELAY, then check_relay
2710 will be skipped. This has an interesting side effect: if your domain is
2711 my.domain and you have
2715 in the access map, then any e-mail with a sender address of
2716 <user@my.domain> will not be rejected by check_relay even though
2717 it would match the hostname or IP address. This allows spammers
2718 to get around DNS based blacklist by faking the sender address. To
2719 avoid this problem you have to use tagged entries:
2722 Connect:my.domain RELAY
2724 if you need those entries at all (class {R} may take care of them).
2726 FEATURE(`delay_checks') can take an optional argument:
2728 FEATURE(`delay_checks', `friend')
2729 enables spamfriend test
2730 FEATURE(`delay_checks', `hater')
2731 enables spamhater test
2733 If such an argument is given, the recipient will be looked up in the
2734 access map (using the tag Spam:). If the argument is `friend', then
2735 the default behavior is to apply the other rulesets and make a SPAM
2736 friend the exception. The rulesets check_mail and check_relay will be
2737 skipped only if the recipient address is found and has RHS FRIEND. If
2738 the argument is `hater', then the default behavior is to skip the rulesets
2739 check_mail and check_relay and make a SPAM hater the exception. The
2740 other two rulesets will be applied only if the recipient address is
2741 found and has RHS HATER.
2743 This allows for simple exceptions from the tests, e.g., by activating
2744 the friend option and having
2748 in the access map, mail to abuse@localdomain will get through (where
2749 "localdomain" is any domain in class {w}). It is also possible to
2750 specify a full address or an address with +detail:
2752 Spam:abuse@my.domain FRIEND
2753 Spam:me+abuse@ FRIEND
2754 Spam:spam.domain FRIEND
2756 Note: The required tag has been changed in 8.12 from To: to Spam:.
2757 This change is incompatible to previous versions. However, you can
2758 (for now) simply add the new entries to the access map, the old
2759 ones will be ignored. As soon as you removed the old entries from
2760 the access map, specify a third parameter (`n') to this feature and
2761 the backward compatibility rules will not be in the generated .cf
2767 You can also reject mail on the basis of the contents of headers.
2768 This is done by adding a ruleset call to the 'H' header definition command
2769 in sendmail.cf. For example, this can be used to check the validity of
2770 a Message-ID: header:
2773 HMessage-Id: $>CheckMessageId
2778 R$* $#error $: 553 Header Error
2780 The alternative format:
2782 HSubject: $>+CheckSubject
2784 that is, $>+ instead of $>, gives the full Subject: header including
2785 comments to the ruleset (comments in parentheses () are stripped
2788 A default ruleset for headers which don't have a specific ruleset
2789 defined for them can be given by:
2794 1. All rules act on tokens as explained in doc/op/op.{me,ps,txt}.
2795 That may cause problems with simple header checks due to the
2796 tokenization. It might be simpler to use a regex map and apply it
2798 2. There are no default rulesets coming with this distribution of
2799 sendmail. You can either write your own or you can search the
2800 WWW for examples, e.g., http://www.digitalanswers.org/check_local/
2801 3. When using a default ruleset for headers, the name of the header
2802 currently being checked can be found in the $&{hdr_name} macro.
2804 After all of the headers are read, the check_eoh ruleset will be called for
2805 any final header-related checks. The ruleset is called with the number of
2806 headers and the size of all of the headers in bytes separated by $|. One
2807 example usage is to reject messages which do not have a Message-Id:
2808 header. However, the Message-Id: header is *NOT* a required header and is
2809 not a guaranteed spam indicator. This ruleset is an example and should
2810 probably not be used in production.
2814 HMessage-Id: $>CheckMessageId
2818 # Record the presence of the header
2819 R$* $: $(storage {MessageIdCheck} $@ OK $) $1
2821 R$* $#error $: 553 Header Error
2825 R$* $: < $&{MessageIdCheck} >
2826 # Clear the macro for the next message
2827 R$* $: $(storage {MessageIdCheck} $) $1
2828 # Has a Message-Id: header
2830 # Allow missing Message-Id: from local mail
2831 R$* $: < $&{client_name} >
2834 # Otherwise, reject the mail
2835 R$* $#error $: 553 Header Error
2838 +--------------------+
2839 | CONNECTION CONTROL |
2840 +--------------------+
2842 The features ratecontrol and conncontrol allow to establish connection
2843 limits per client IP address or net. These features can limit the
2844 rate of connections (connections per time unit) or the number of
2845 incoming SMTP connections, respectively. If enabled, appropriate
2846 rulesets are called at the end of check_relay, i.e., after DNS
2847 blacklists and generic access_db operations. The features require
2848 FEATURE(`access_db') to be listed earlier in the mc file.
2850 Note: FEATURE(`delay_checks') delays those connection control checks
2851 after a recipient address has been received, hence making these
2852 connection control features less useful. To run the checks as early
2853 as possible, specify the parameter `nodelay', e.g.,
2855 FEATURE(`ratecontrol', `nodelay')
2857 In that case, FEATURE(`delay_checks') has no effect on connection
2858 control (and it must be specified earlier in the mc file).
2860 An optional second argument `terminate' specifies whether the
2861 rulesets should return the error code 421 which will cause
2862 sendmail to terminate the session with that error if it is
2863 returned from check_relay, i.e., not delayed as explained in
2864 the previous paragraph. Example:
2866 FEATURE(`ratecontrol', `nodelay', `terminate')
2873 In this text, cert will be used as an abbreviation for X.509 certificate,
2874 DN (CN) is the distinguished (common) name of a cert, and CA is a
2875 certification authority, which signs (issues) certs.
2877 For STARTTLS to be offered by sendmail you need to set at least
2878 these variables (the file names and paths are just examples):
2880 define(`confCACERT_PATH', `/etc/mail/certs/')
2881 define(`confCACERT', `/etc/mail/certs/CA.cert.pem')
2882 define(`confSERVER_CERT', `/etc/mail/certs/my.cert.pem')
2883 define(`confSERVER_KEY', `/etc/mail/certs/my.key.pem')
2885 On systems which do not have the compile flag HASURANDOM set (see
2886 sendmail/README) you also must set confRAND_FILE.
2888 See doc/op/op.{me,ps,txt} for more information about these options,
2889 especially the sections ``Certificates for STARTTLS'' and ``PRNG for
2892 Macros related to STARTTLS are:
2894 ${cert_issuer} holds the DN of the CA (the cert issuer).
2895 ${cert_subject} holds the DN of the cert (called the cert subject).
2896 ${cn_issuer} holds the CN of the CA (the cert issuer).
2897 ${cn_subject} holds the CN of the cert (called the cert subject).
2898 ${tls_version} the TLS/SSL version used for the connection, e.g., TLSv1,
2899 TLSv1/SSLv3, SSLv3, SSLv2.
2900 ${cipher} the cipher used for the connection, e.g., EDH-DSS-DES-CBC3-SHA,
2901 EDH-RSA-DES-CBC-SHA, DES-CBC-MD5, DES-CBC3-SHA.
2902 ${cipher_bits} the keylength (in bits) of the symmetric encryption algorithm
2903 used for the connection.
2904 ${verify} holds the result of the verification of the presented cert.
2905 Possible values are:
2906 OK verification succeeded.
2907 NO no cert presented.
2908 NOT no cert requested.
2909 FAIL cert presented but could not be verified,
2910 e.g., the cert of the signing CA is missing.
2911 NONE STARTTLS has not been performed.
2912 TEMP temporary error occurred.
2913 PROTOCOL protocol error occurred (SMTP level).
2914 SOFTWARE STARTTLS handshake failed.
2915 ${server_name} the name of the server of the current outgoing SMTP
2917 ${server_addr} the address of the server of the current outgoing SMTP
2923 SMTP STARTTLS can allow relaying for remote SMTP clients which have
2924 successfully authenticated themselves. If the verification of the cert
2925 failed (${verify} != OK), relaying is subject to the usual rules.
2926 Otherwise the DN of the issuer is looked up in the access map using the
2927 tag CERTISSUER. If the resulting value is RELAY, relaying is allowed.
2928 If it is SUBJECT, the DN of the cert subject is looked up next in the
2929 access map using the tag CERTSUBJECT. If the value is RELAY, relaying
2932 To make things a bit more flexible (or complicated), the values for
2933 ${cert_issuer} and ${cert_subject} can be optionally modified by regular
2934 expressions defined in the m4 variables _CERT_REGEX_ISSUER_ and
2935 _CERT_REGEX_SUBJECT_, respectively. To avoid problems with those macros in
2936 rulesets and map lookups, they are modified as follows: each non-printable
2937 character and the characters '<', '>', '(', ')', '"', '+', ' ' are replaced
2938 by their HEX value with a leading '+'. For example:
2940 /C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/Email=
2941 darth+cert@endmail.org
2945 /C=US/ST=California/O=endmail.org/OU=private/CN=
2946 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
2948 (line breaks have been inserted for readability).
2950 The macros which are subject to this encoding are ${cert_subject},
2951 ${cert_issuer}, ${cn_subject}, and ${cn_issuer}.
2955 To allow relaying for everyone who can present a cert signed by
2957 /C=US/ST=California/O=endmail.org/OU=private/CN=
2958 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
2962 CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
2963 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org RELAY
2965 To allow relaying only for a subset of machines that have a cert signed by
2967 /C=US/ST=California/O=endmail.org/OU=private/CN=
2968 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org
2972 CertIssuer:/C=US/ST=California/O=endmail.org/OU=private/CN=
2973 Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org SUBJECT
2974 CertSubject:/C=US/ST=California/O=endmail.org/OU=private/CN=
2975 DeathStar/Email=deathstar@endmail.org RELAY
2978 - line breaks have been inserted after "CN=" for readability,
2979 each tagged entry must be one (long) line in the access map.
2980 - if OpenSSL 0.9.7 or newer is used then the "Email=" part of a DN
2981 is replaced by "emailAddress=".
2983 Of course it is also possible to write a simple ruleset that allows
2984 relaying for everyone who can present a cert that can be verified, e.g.,
2991 Allowing Connections
2992 --------------------
2994 The rulesets tls_server, tls_client, and tls_rcpt are used to decide whether
2995 an SMTP connection is accepted (or should continue).
2997 tls_server is called when sendmail acts as client after a STARTTLS command
2998 (should) have been issued. The parameter is the value of ${verify}.
3000 tls_client is called when sendmail acts as server, after a STARTTLS command
3001 has been issued, and from check_mail. The parameter is the value of
3002 ${verify} and STARTTLS or MAIL, respectively.
3004 Both rulesets behave the same. If no access map is in use, the connection
3005 will be accepted unless ${verify} is SOFTWARE, in which case the connection
3006 is always aborted. For tls_server/tls_client, ${client_name}/${server_name}
3007 is looked up in the access map using the tag TLS_Srv/TLS_Clt, which is done
3008 with the ruleset LookUpDomain. If no entry is found, ${client_addr}
3009 (${server_addr}) is looked up in the access map (same tag, ruleset
3010 LookUpAddr). If this doesn't result in an entry either, just the tag is
3011 looked up in the access map (included the trailing colon). Notice:
3012 requiring that e-mail is sent to a server only encrypted, e.g., via
3014 TLS_Srv:secure.domain ENCR:112
3016 doesn't necessarily mean that e-mail sent to that domain is encrypted.
3017 If the domain has multiple MX servers, e.g.,
3019 secure.domain. IN MX 10 mail.secure.domain.
3020 secure.domain. IN MX 50 mail.other.domain.
3022 then mail to user@secure.domain may go unencrypted to mail.other.domain.
3023 tls_rcpt can be used to address this problem.
3025 tls_rcpt is called before a RCPT TO: command is sent. The parameter is the
3026 current recipient. This ruleset is only defined if FEATURE(`access_db')
3027 is selected. A recipient address user@domain is looked up in the access
3028 map in four formats: TLS_Rcpt:user@domain, TLS_Rcpt:user@, TLS_Rcpt:domain,
3029 and TLS_Rcpt:; the first match is taken.
3031 The result of the lookups is then used to call the ruleset TLS_connection,
3032 which checks the requirement specified by the RHS in the access map against
3033 the actual parameters of the current TLS connection, esp. ${verify} and
3034 ${cipher_bits}. Legal RHSs in the access map are:
3036 VERIFY verification must have succeeded
3037 VERIFY:bits verification must have succeeded and ${cipher_bits} must
3038 be greater than or equal bits.
3039 ENCR:bits ${cipher_bits} must be greater than or equal bits.
3041 The RHS can optionally be prefixed by TEMP+ or PERM+ to select a temporary
3042 or permanent error. The default is a temporary error code (403 4.7.0)
3043 unless the macro TLS_PERM_ERR is set during generation of the .cf file.
3045 If a certain level of encryption is required, then it might also be
3046 possible that this level is provided by the security layer from a SASL
3047 algorithm, e.g., DIGEST-MD5.
3049 Furthermore, there can be a list of extensions added. Such a list
3050 starts with '+' and the items are separated by '++'. Allowed
3053 CN:name name must match ${cn_subject}
3054 CN ${server_name} must match ${cn_subject}
3055 CS:name name must match ${cert_subject}
3056 CI:name name must match ${cert_issuer}
3058 Example: e-mail sent to secure.example.com should only use an encrypted
3059 connection. E-mail received from hosts within the laptop.example.com domain
3060 should only be accepted if they have been authenticated. The host which
3061 receives e-mail for darth@endmail.org must present a cert that uses the
3062 CN smtp.endmail.org.
3064 TLS_Srv:secure.example.com ENCR:112
3065 TLS_Clt:laptop.example.com PERM+VERIFY:112
3066 TLS_Rcpt:darth@endmail.org ENCR:112+CN:smtp.endmail.org
3069 Disabling STARTTLS And Setting SMTP Server Features
3070 ---------------------------------------------------
3072 By default STARTTLS is used whenever possible. However, there are
3073 some broken MTAs that don't properly implement STARTTLS. To be able
3074 to send to (or receive from) those MTAs, the ruleset try_tls
3075 (srv_features) can be used that work together with the access map.
3076 Entries for the access map must be tagged with Try_TLS (Srv_Features)
3077 and refer to the hostname or IP address of the connecting system.
3078 A default case can be specified by using just the tag. For example,
3079 the following entries in the access map:
3081 Try_TLS:broken.server NO
3082 Srv_Features:my.domain v
3085 will turn off STARTTLS when sending to broken.server (or any host
3086 in that domain), and request a client certificate during the TLS
3087 handshake only for hosts in my.domain. The valid entries on the RHS
3088 for Srv_Features are listed in the Sendmail Installation and
3095 The Received: header reveals whether STARTTLS has been used. It contains an
3098 (version=${tls_version} cipher=${cipher} bits=${cipher_bits} verify=${verify})
3101 +---------------------+
3102 | SMTP AUTHENTICATION |
3103 +---------------------+
3105 The macros ${auth_authen}, ${auth_author}, and ${auth_type} can be
3106 used in anti-relay rulesets to allow relaying for those users that
3107 authenticated themselves. A very simple example is:
3110 R$* $: $&{auth_type}
3113 which checks whether a user has successfully authenticated using
3114 any available mechanism. Depending on the setup of the Cyrus SASL
3115 library, more sophisticated rulesets might be required, e.g.,
3118 R$* $: $&{auth_type} $| $&{auth_authen}
3119 RDIGEST-MD5 $| $+@$=w $# OK
3121 to allow relaying for users that authenticated using DIGEST-MD5
3122 and have an identity in the local domains.
3124 The ruleset trust_auth is used to determine whether a given AUTH=
3125 parameter (that is passed to this ruleset) should be trusted. This
3126 ruleset may make use of the other ${auth_*} macros. Only if the
3127 ruleset resolves to the error mailer, the AUTH= parameter is not
3128 trusted. A user supplied ruleset Local_trust_auth can be written
3129 to modify the default behavior, which only trust the AUTH=
3130 parameter if it is identical to the authenticated user.
3132 Per default, relaying is allowed for any user who authenticated
3133 via a "trusted" mechanism, i.e., one that is defined via
3134 TRUST_AUTH_MECH(`list of mechanisms')
3136 TRUST_AUTH_MECH(`KERBEROS_V4 DIGEST-MD5')
3138 If the selected mechanism provides a security layer the number of
3139 bits used for the key of the symmetric cipher is stored in the
3142 Providing SMTP AUTH Data when sendmail acts as Client
3143 -----------------------------------------------------
3145 If sendmail acts as client, it needs some information how to
3146 authenticate against another MTA. This information can be provided
3147 by the ruleset authinfo or by the option DefaultAuthInfo. The
3148 authinfo ruleset looks up {server_name} using the tag AuthInfo: in
3149 the access map. If no entry is found, {server_addr} is looked up
3150 in the same way and finally just the tag AuthInfo: to provide
3151 default values. Note: searches for domain parts or IP nets are
3152 only performed if the access map is used; if the authinfo feature
3153 is used then only up to three lookups are performed (two exact
3154 matches, one default).
3156 Note: If your daemon does client authentication when sending, and
3157 if it uses either PLAIN or LOGIN authentication, then you *must*
3158 prevent ordinary users from seeing verbose output. Do NOT install
3159 sendmail set-user-ID. Use PrivacyOptions to turn off verbose output
3160 ("goaway" works for this).
3162 Notice: the default configuration file causes the option DefaultAuthInfo
3163 to fail since the ruleset authinfo is in the .cf file. If you really
3164 want to use DefaultAuthInfo (it is deprecated) then you have to
3167 The RHS for an AuthInfo: entry in the access map should consists of a
3168 list of tokens, each of which has the form: "TDstring" (including
3169 the quotes). T is a tag which describes the item, D is a delimiter,
3170 either ':' for simple text or '=' for a base64 encoded string.
3171 Valid values for the tag are:
3173 U user (authorization) id
3177 M list of mechanisms delimited by spaces
3179 Example entries are:
3181 AuthInfo:other.dom "U:user" "I:user" "P:secret" "R:other.dom" "M:DIGEST-MD5"
3182 AuthInfo:host.more.dom "U:user" "P=c2VjcmV0"
3184 User id or authentication id must exist as well as the password. All
3185 other entries have default values. If one of user or authentication
3186 id is missing, the existing value is used for the missing item.
3187 If "R:" is not specified, realm defaults to $j. The list of mechanisms
3188 defaults to those specified by AuthMechanisms.
3190 Since this map contains sensitive information, either the access
3191 map must be unreadable by everyone but root (or the trusted user)
3192 or FEATURE(`authinfo') must be used which provides a separate map.
3193 Notice: It is not checked whether the map is actually
3194 group/world-unreadable, this is left to the user.
3196 +--------------------------------+
3197 | ADDING NEW MAILERS OR RULESETS |
3198 +--------------------------------+
3200 Sometimes you may need to add entirely new mailers or rulesets. They
3201 should be introduced with the constructs MAILER_DEFINITIONS and
3202 LOCAL_RULESETS respectively. For example:
3212 Local additions for the rulesets srv_features, try_tls, tls_rcpt,
3213 tls_client, and tls_server can be made using LOCAL_SRV_FEATURES,
3214 LOCAL_TRY_TLS, LOCAL_TLS_RCPT, LOCAL_TLS_CLIENT, and LOCAL_TLS_SERVER,
3215 respectively. For example, to add a local ruleset that decides
3216 whether to try STARTTLS in a sendmail client, use:
3221 Note: you don't need to add a name for the ruleset, it is implicitly
3222 defined by using the appropriate macro.
3225 +-------------------------+
3226 | ADDING NEW MAIL FILTERS |
3227 +-------------------------+
3229 Sendmail supports mail filters to filter incoming SMTP messages according
3230 to the "Sendmail Mail Filter API" documentation. These filters can be
3231 configured in your mc file using the two commands:
3233 MAIL_FILTER(`name', `equates')
3234 INPUT_MAIL_FILTER(`name', `equates')
3236 The first command, MAIL_FILTER(), simply defines a filter with the given
3237 name and equates. For example:
3239 MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3241 This creates the equivalent sendmail.cf entry:
3243 Xarchive, S=local:/var/run/archivesock, F=R
3245 The INPUT_MAIL_FILTER() command performs the same actions as MAIL_FILTER
3246 but also populates the m4 variable `confINPUT_MAIL_FILTERS' with the name
3247 of the filter such that the filter will actually be called by sendmail.
3249 For example, the two commands:
3251 INPUT_MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3252 INPUT_MAIL_FILTER(`spamcheck', `S=inet:2525@localhost, F=T')
3254 are equivalent to the three commands:
3256 MAIL_FILTER(`archive', `S=local:/var/run/archivesock, F=R')
3257 MAIL_FILTER(`spamcheck', `S=inet:2525@localhost, F=T')
3258 define(`confINPUT_MAIL_FILTERS', `archive, spamcheck')
3260 In general, INPUT_MAIL_FILTER() should be used unless you need to define
3261 more filters than you want to use for `confINPUT_MAIL_FILTERS'.
3263 Note that setting `confINPUT_MAIL_FILTERS' after any INPUT_MAIL_FILTER()
3264 commands will clear the list created by the prior INPUT_MAIL_FILTER()
3268 +-------------------------+
3269 | QUEUE GROUP DEFINITIONS |
3270 +-------------------------+
3272 In addition to the queue directory (which is the default queue group
3273 called "mqueue"), sendmail can deal with multiple queue groups, which
3274 are collections of queue directories with the same behaviour. Queue
3275 groups can be defined using the command:
3277 QUEUE_GROUP(`name', `equates')
3279 For details about queue groups, please see doc/op/op.{me,ps,txt}.
3281 +-------------------------------+
3282 | NON-SMTP BASED CONFIGURATIONS |
3283 +-------------------------------+
3285 These configuration files are designed primarily for use by
3286 SMTP-based sites. They may not be well tuned for UUCP-only or
3287 UUCP-primarily nodes (the latter is defined as a small local net
3288 connected to the rest of the world via UUCP). However, there is
3289 one hook to handle some special cases.
3291 You can define a ``smart host'' that understands a richer address syntax
3294 define(`SMART_HOST', `mailer:hostname')
3296 In this case, the ``mailer:'' defaults to "relay". Any messages that
3297 can't be handled using the usual UUCP rules are passed to this host.
3299 If you are on a local SMTP-based net that connects to the outside
3300 world via UUCP, you can use LOCAL_NET_CONFIG to add appropriate rules.
3303 define(`SMART_HOST', `uucp-new:uunet')
3305 R$* < @ $* .$m. > $* $#smtp $@ $2.$m. $: $1 < @ $2.$m. > $3
3307 This will cause all names that end in your domain name ($m) to be sent
3308 via SMTP; anything else will be sent via uucp-new (smart UUCP) to uunet.
3309 If you have FEATURE(`nocanonify'), you may need to omit the dots after
3310 the $m. If you are running a local DNS inside your domain which is
3311 not otherwise connected to the outside world, you probably want to
3314 define(`SMART_HOST', `smtp:fire.wall.com')
3316 R$* < @ $* . > $* $#smtp $@ $2. $: $1 < @ $2. > $3
3318 That is, send directly only to things you found in your DNS lookup;
3319 anything else goes through SMART_HOST.
3321 You may need to turn off the anti-spam rules in order to accept
3322 UUCP mail with FEATURE(`promiscuous_relay') and
3323 FEATURE(`accept_unresolvable_domains').
3330 Normally, the $j macro is automatically defined to be your fully
3331 qualified domain name (FQDN). Sendmail does this by getting your
3332 host name using gethostname and then calling gethostbyname on the
3333 result. For example, in some environments gethostname returns
3334 only the root of the host name (such as "foo"); gethostbyname is
3335 supposed to return the FQDN ("foo.bar.com"). In some (fairly rare)
3336 cases, gethostbyname may fail to return the FQDN. In this case
3337 you MUST define confDOMAIN_NAME to be your fully qualified domain
3338 name. This is usually done using:
3341 define(`confDOMAIN_NAME', `$w.$m')dnl
3344 +-----------------------------------+
3345 | ACCEPTING MAIL FOR MULTIPLE NAMES |
3346 +-----------------------------------+
3348 If your host is known by several different names, you need to augment
3349 class {w}. This is a list of names by which your host is known, and
3350 anything sent to an address using a host name in this list will be
3351 treated as local mail. You can do this in two ways: either create the
3352 file /etc/mail/local-host-names containing a list of your aliases (one per
3353 line), and use ``FEATURE(`use_cw_file')'' in the .mc file, or add
3354 ``LOCAL_DOMAIN(`alias.host.name')''. Be sure you use the fully-qualified
3355 name of the host, rather than a short name.
3357 If you want to have different address in different domains, take
3358 a look at the virtusertable feature, which is also explained at
3359 http://www.sendmail.org/virtual-hosting.html
3362 +--------------------+
3363 | USING MAILERTABLES |
3364 +--------------------+
3366 To use FEATURE(`mailertable'), you will have to create an external
3367 database containing the routing information for various domains.
3368 For example, a mailertable file in text format might be:
3370 .my.domain xnet:%1.my.domain
3371 uuhost1.my.domain uucp-new:uuhost1
3372 .bitnet smtp:relay.bit.net
3374 This should normally be stored in /etc/mail/mailertable. The actual
3375 database version of the mailertable is built using:
3377 makemap hash /etc/mail/mailertable < /etc/mail/mailertable
3379 The semantics are simple. Any LHS entry that does not begin with
3380 a dot matches the full host name indicated. LHS entries beginning
3381 with a dot match anything ending with that domain name (including
3382 the leading dot) -- that is, they can be thought of as having a
3383 leading ".+" regular expression pattern for a non-empty sequence of
3384 characters. Matching is done in order of most-to-least qualified
3385 -- for example, even though ".my.domain" is listed first in the
3386 above example, an entry of "uuhost1.my.domain" will match the second
3387 entry since it is more explicit. Note: e-mail to "user@my.domain"
3388 does not match any entry in the above table. You need to have
3391 my.domain esmtp:host.my.domain
3393 The RHS should always be a "mailer:host" pair. The mailer is the
3394 configuration name of a mailer (that is, an M line in the
3395 sendmail.cf file). The "host" will be the hostname passed to
3396 that mailer. In domain-based matches (that is, those with leading
3397 dots) the "%1" may be used to interpolate the wildcarded part of
3398 the host name. For example, the first line above sends everything
3399 addressed to "anything.my.domain" to that same host name, but using
3400 the (presumably experimental) xnet mailer.
3402 In some cases you may want to temporarily turn off MX records,
3403 particularly on gateways. For example, you may want to MX
3404 everything in a domain to one machine that then forwards it
3405 directly. To do this, you might use the DNS configuration:
3407 *.domain. IN MX 0 relay.machine
3409 and on relay.machine use the mailertable:
3411 .domain smtp:[gateway.domain]
3413 The [square brackets] turn off MX records for this host only.
3414 If you didn't do this, the mailertable would use the MX record
3415 again, which would give you an MX loop. Note that the use of
3416 wildcard MX records is almost always a bad idea. Please avoid
3417 using them if possible.
3420 +--------------------------------+
3421 | USING USERDB TO MAP FULL NAMES |
3422 +--------------------------------+
3424 The user database was not originally intended for mapping full names
3425 to login names (e.g., Eric.Allman => eric), but some people are using
3426 it that way. (it is recommended that you set up aliases for this
3427 purpose instead -- since you can specify multiple alias files, this
3428 is fairly easy.) The intent was to locate the default maildrop at
3429 a site, but allow you to override this by sending to a specific host.
3431 If you decide to set up the user database in this fashion, it is
3432 imperative that you not use FEATURE(`stickyhost') -- otherwise,
3433 e-mail sent to Full.Name@local.host.name will be rejected.
3435 To build the internal form of the user database, use:
3437 makemap btree /etc/mail/userdb < /etc/mail/userdb.txt
3439 As a general rule, it is an extremely bad idea to using full names
3440 as e-mail addresses, since they are not in any sense unique. For
3441 example, the UNIX software-development community has at least two
3442 well-known Peter Deutsches, and at one time Bell Labs had two
3443 Stephen R. Bournes with offices along the same hallway. Which one
3444 will be forced to suffer the indignity of being Stephen_R_Bourne_2?
3445 The less famous of the two, or the one that was hired later?
3447 Finger should handle full names (and be fuzzy). Mail should use
3448 handles, and not be fuzzy.
3451 +--------------------------------+
3452 | MISCELLANEOUS SPECIAL FEATURES |
3453 +--------------------------------+
3456 Sometimes it is convenient to merge configuration on a
3457 centralized mail machine, for example, to forward all
3458 root mail to a mail server. In this case it might be
3459 useful to be able to treat the root addresses as a class
3460 of addresses with subtle differences. You can do this
3461 using plussed users. For example, a client might include
3464 root: root+client1@server
3466 On the server, this will match an alias for "root+client1".
3467 If that is not found, the alias "root+*" will be tried,
3475 A lot of sendmail security comes down to you. Sendmail 8 is much
3476 more careful about checking for security problems than previous
3477 versions, but there are some things that you still need to watch
3480 * Make sure the aliases file is not writable except by trusted
3481 system personnel. This includes both the text and database
3484 * Make sure that other files that sendmail reads, such as the
3485 mailertable, are only writable by trusted system personnel.
3487 * The queue directory should not be world writable PARTICULARLY
3488 if your system allows "file giveaways" (that is, if a non-root
3489 user can chown any file they own to any other user).
3491 * If your system allows file giveaways, DO NOT create a publically
3492 writable directory for forward files. This will allow anyone
3493 to steal anyone else's e-mail. Instead, create a script that
3494 copies the .forward file from users' home directories once a
3495 night (if you want the non-NFS-mounted forward directory).
3497 * If your system allows file giveaways, you'll find that
3498 sendmail is much less trusting of :include: files -- in
3499 particular, you'll have to have /SENDMAIL/ANY/SHELL/ in
3500 /etc/shells before they will be trusted (that is, before
3501 files and programs listed in them will be honored).
3503 In general, file giveaways are a mistake -- if you can turn them
3507 +--------------------------------+
3508 | TWEAKING CONFIGURATION OPTIONS |
3509 +--------------------------------+
3511 There are a large number of configuration options that don't normally
3512 need to be changed. However, if you feel you need to tweak them,
3513 you can define the following M4 variables. Note that some of these
3514 variables require formats that are defined in RFC 2821 or RFC 2822.
3515 Before changing them you need to make sure you do not violate those
3516 (and other relevant) RFCs.
3518 This list is shown in four columns: the name you define, the default
3519 value for that definition, the option or macro that is affected
3520 (either Ox for an option or Dx for a macro), and a brief description.
3521 Greater detail of the semantics can be found in the Installation
3522 and Operations Guide.
3524 Some options are likely to be deprecated in future versions -- that is,
3525 the option is only included to provide back-compatibility. These are
3528 Remember that these options are M4 variables, and hence may need to
3529 be quoted. In particular, arguments with commas will usually have to
3530 be ``double quoted, like this phrase'' to avoid having the comma
3531 confuse things. This is common for alias file definitions and for
3534 M4 Variable Name Configuration [Default] & Description
3535 ================ ============= =======================
3536 confMAILER_NAME $n macro [MAILER-DAEMON] The sender name used
3537 for internally generated outgoing
3539 confDOMAIN_NAME $j macro If defined, sets $j. This should
3540 only be done if your system cannot
3541 determine your local domain name,
3542 and then it should be set to
3543 $w.Foo.COM, where Foo.COM is your
3545 confCF_VERSION $Z macro If defined, this is appended to the
3546 configuration version name.
3547 confLDAP_CLUSTER ${sendmailMTACluster} macro
3548 If defined, this is the LDAP
3549 cluster to use for LDAP searches
3550 as described above in ``USING LDAP
3551 FOR ALIASES, MAPS, AND CLASSES''.
3552 confFROM_HEADER From: [$?x$x <$g>$|$g$.] The format of an
3553 internally generated From: address.
3554 confRECEIVED_HEADER Received:
3555 [$?sfrom $s $.$?_($?s$|from $.$_)
3556 $.$?{auth_type}(authenticated)
3557 $.by $j ($v/$Z)$?r with $r$. id $i$?u
3560 The format of the Received: header
3561 in messages passed through this host.
3562 It is unwise to try to change this.
3563 confMESSAGEID_HEADER Message-Id: [<$t.$i@$j>] The format of an
3564 internally generated Message-Id:
3566 confCW_FILE Fw class [/etc/mail/local-host-names] Name
3567 of file used to get the local
3568 additions to class {w} (local host
3570 confCT_FILE Ft class [/etc/mail/trusted-users] Name of
3571 file used to get the local additions
3572 to class {t} (trusted users).
3573 confCR_FILE FR class [/etc/mail/relay-domains] Name of
3574 file used to get the local additions
3575 to class {R} (hosts allowed to relay).
3576 confTRUSTED_USERS Ct class [no default] Names of users to add to
3577 the list of trusted users. This list
3578 always includes root, uucp, and daemon.
3579 See also FEATURE(`use_ct_file').
3580 confTRUSTED_USER TrustedUser [no default] Trusted user for file
3581 ownership and starting the daemon.
3582 Not to be confused with
3583 confTRUSTED_USERS (see above).
3584 confSMTP_MAILER - [esmtp] The mailer name used when
3585 SMTP connectivity is required.
3586 One of "smtp", "smtp8",
3587 "esmtp", or "dsmtp".
3588 confUUCP_MAILER - [uucp-old] The mailer to be used by
3589 default for bang-format recipient
3590 addresses. See also discussion of
3591 class {U}, class {Y}, and class {Z}
3592 in the MAILER(`uucp') section.
3593 confLOCAL_MAILER - [local] The mailer name used when
3594 local connectivity is required.
3595 Almost always "local".
3596 confRELAY_MAILER - [relay] The default mailer name used
3597 for relaying any mail (e.g., to a
3598 BITNET_RELAY, a SMART_HOST, or
3599 whatever). This can reasonably be
3600 "uucp-new" if you are on a
3601 UUCP-connected site.
3602 confSEVEN_BIT_INPUT SevenBitInput [False] Force input to seven bits?
3603 confEIGHT_BIT_HANDLING EightBitMode [pass8] 8-bit data handling
3604 confALIAS_WAIT AliasWait [10m] Time to wait for alias file
3605 rebuild until you get bored and
3606 decide that the apparently pending
3608 confMIN_FREE_BLOCKS MinFreeBlocks [100] Minimum number of free blocks on
3609 queue filesystem to accept SMTP mail.
3610 (Prior to 8.7 this was minfree/maxsize,
3611 where minfree was the number of free
3612 blocks and maxsize was the maximum
3613 message size. Use confMAX_MESSAGE_SIZE
3614 for the second value now.)
3615 confMAX_MESSAGE_SIZE MaxMessageSize [infinite] The maximum size of messages
3616 that will be accepted (in bytes).
3617 confBLANK_SUB BlankSub [.] Blank (space) substitution
3619 confCON_EXPENSIVE HoldExpensive [False] Avoid connecting immediately
3620 to mailers marked expensive.
3621 confCHECKPOINT_INTERVAL CheckpointInterval
3622 [10] Checkpoint queue files every N
3624 confDELIVERY_MODE DeliveryMode [background] Default delivery mode.
3625 confERROR_MODE ErrorMode [print] Error message mode.
3626 confERROR_MESSAGE ErrorHeader [undefined] Error message header/file.
3627 confSAVE_FROM_LINES SaveFromLine Save extra leading From_ lines.
3628 confTEMP_FILE_MODE TempFileMode [0600] Temporary file mode.
3629 confMATCH_GECOS MatchGECOS [False] Match GECOS field.
3630 confMAX_HOP MaxHopCount [25] Maximum hop count.
3631 confIGNORE_DOTS* IgnoreDots [False; always False in -bs or -bd
3632 mode] Ignore dot as terminator for
3634 confBIND_OPTS ResolverOptions [undefined] Default options for DNS
3636 confMIME_FORMAT_ERRORS* SendMimeErrors [True] Send error messages as MIME-
3637 encapsulated messages per RFC 1344.
3638 confFORWARD_PATH ForwardPath [$z/.forward.$w:$z/.forward]
3639 The colon-separated list of places to
3640 search for .forward files. N.B.: see
3641 the Security Notes section.
3642 confMCI_CACHE_SIZE ConnectionCacheSize
3643 [2] Size of open connection cache.
3644 confMCI_CACHE_TIMEOUT ConnectionCacheTimeout
3645 [5m] Open connection cache timeout.
3646 confHOST_STATUS_DIRECTORY HostStatusDirectory
3647 [undefined] If set, host status is kept
3648 on disk between sendmail runs in the
3649 named directory tree. This need not be
3650 a full pathname, in which case it is
3651 interpreted relative to the queue
3653 confSINGLE_THREAD_DELIVERY SingleThreadDelivery
3654 [False] If this option and the
3655 HostStatusDirectory option are both
3656 set, single thread deliveries to other
3657 hosts. That is, don't allow any two
3658 sendmails on this host to connect
3659 simultaneously to any other single
3660 host. This can slow down delivery in
3661 some cases, in particular since a
3662 cached but otherwise idle connection
3663 to a host will prevent other sendmails
3664 from connecting to the other host.
3665 confUSE_ERRORS_TO* UseErrorsTo [False] Use the Errors-To: header to
3666 deliver error messages. This should
3667 not be necessary because of general
3668 acceptance of the envelope/header
3670 confLOG_LEVEL LogLevel [9] Log level.
3671 confME_TOO MeToo [True] Include sender in group
3672 expansions. This option is
3673 deprecated and will be removed from
3675 confCHECK_ALIASES CheckAliases [False] Check RHS of aliases when
3676 running newaliases. Since this does
3677 DNS lookups on every address, it can
3678 slow down the alias rebuild process
3679 considerably on large alias files.
3680 confOLD_STYLE_HEADERS* OldStyleHeaders [True] Assume that headers without
3681 special chars are old style.
3682 confPRIVACY_FLAGS PrivacyOptions [authwarnings] Privacy flags.
3683 confCOPY_ERRORS_TO PostmasterCopy [undefined] Address for additional
3684 copies of all error messages.
3685 confQUEUE_FACTOR QueueFactor [600000] Slope of queue-only function.
3686 confQUEUE_FILE_MODE QueueFileMode [undefined] Default permissions for
3687 queue files (octal). If not set,
3688 sendmail uses 0600 unless its real
3689 and effective uid are different in
3690 which case it uses 0644.
3691 confDONT_PRUNE_ROUTES DontPruneRoutes [False] Don't prune down route-addr
3692 syntax addresses to the minimum
3694 confSAFE_QUEUE* SuperSafe [True] Commit all messages to disk
3696 confTO_INITIAL Timeout.initial [5m] The timeout waiting for a response
3697 on the initial connect.
3698 confTO_CONNECT Timeout.connect [0] The timeout waiting for an initial
3699 connect() to complete. This can only
3700 shorten connection timeouts; the kernel
3701 silently enforces an absolute maximum
3702 (which varies depending on the system).
3703 confTO_ICONNECT Timeout.iconnect
3704 [undefined] Like Timeout.connect, but
3705 applies only to the very first attempt
3706 to connect to a host in a message.
3707 This allows a single very fast pass
3708 followed by more careful delivery
3709 attempts in the future.
3710 confTO_ACONNECT Timeout.aconnect
3711 [0] The overall timeout waiting for
3712 all connection for a single delivery
3713 attempt to succeed. If 0, no overall
3715 confTO_HELO Timeout.helo [5m] The timeout waiting for a response
3716 to a HELO or EHLO command.
3717 confTO_MAIL Timeout.mail [10m] The timeout waiting for a
3718 response to the MAIL command.
3719 confTO_RCPT Timeout.rcpt [1h] The timeout waiting for a response
3720 to the RCPT command.
3721 confTO_DATAINIT Timeout.datainit
3722 [5m] The timeout waiting for a 354
3723 response from the DATA command.
3724 confTO_DATABLOCK Timeout.datablock
3725 [1h] The timeout waiting for a block
3727 confTO_DATAFINAL Timeout.datafinal
3728 [1h] The timeout waiting for a response
3729 to the final "." that terminates a
3731 confTO_RSET Timeout.rset [5m] The timeout waiting for a response
3732 to the RSET command.
3733 confTO_QUIT Timeout.quit [2m] The timeout waiting for a response
3734 to the QUIT command.
3735 confTO_MISC Timeout.misc [2m] The timeout waiting for a response
3736 to other SMTP commands.
3737 confTO_COMMAND Timeout.command [1h] In server SMTP, the timeout
3738 waiting for a command to be issued.
3739 confTO_IDENT Timeout.ident [5s] The timeout waiting for a
3740 response to an IDENT query.
3741 confTO_FILEOPEN Timeout.fileopen
3742 [60s] The timeout waiting for a file
3743 (e.g., :include: file) to be opened.
3744 confTO_LHLO Timeout.lhlo [2m] The timeout waiting for a response
3745 to an LMTP LHLO command.
3746 confTO_AUTH Timeout.auth [10m] The timeout waiting for a
3747 response in an AUTH dialogue.
3748 confTO_STARTTLS Timeout.starttls
3749 [1h] The timeout waiting for a
3750 response to an SMTP STARTTLS command.
3751 confTO_CONTROL Timeout.control
3752 [2m] The timeout for a complete
3753 control socket transaction to complete.
3754 confTO_QUEUERETURN Timeout.queuereturn
3755 [5d] The timeout before a message is
3756 returned as undeliverable.
3757 confTO_QUEUERETURN_NORMAL
3758 Timeout.queuereturn.normal
3759 [undefined] As above, for normal
3761 confTO_QUEUERETURN_URGENT
3762 Timeout.queuereturn.urgent
3763 [undefined] As above, for urgent
3765 confTO_QUEUERETURN_NONURGENT
3766 Timeout.queuereturn.non-urgent
3767 [undefined] As above, for non-urgent
3768 (low) priority messages.
3769 confTO_QUEUERETURN_DSN
3770 Timeout.queuereturn.dsn
3771 [undefined] As above, for delivery
3772 status notification messages.
3773 confTO_QUEUEWARN Timeout.queuewarn
3774 [4h] The timeout before a warning
3775 message is sent to the sender telling
3776 them that the message has been
3778 confTO_QUEUEWARN_NORMAL Timeout.queuewarn.normal
3779 [undefined] As above, for normal
3781 confTO_QUEUEWARN_URGENT Timeout.queuewarn.urgent
3782 [undefined] As above, for urgent
3784 confTO_QUEUEWARN_NONURGENT
3785 Timeout.queuewarn.non-urgent
3786 [undefined] As above, for non-urgent
3787 (low) priority messages.
3788 confTO_QUEUEWARN_DSN
3789 Timeout.queuewarn.dsn
3790 [undefined] As above, for delivery
3791 status notification messages.
3792 confTO_HOSTSTATUS Timeout.hoststatus
3793 [30m] How long information about host
3794 statuses will be maintained before it
3795 is considered stale and the host should
3796 be retried. This applies both within
3797 a single queue run and to persistent
3798 information (see below).
3799 confTO_RESOLVER_RETRANS Timeout.resolver.retrans
3800 [varies] Sets the resolver's
3801 retransmission time interval (in
3803 Timeout.resolver.retrans.first and
3804 Timeout.resolver.retrans.normal.
3805 confTO_RESOLVER_RETRANS_FIRST Timeout.resolver.retrans.first
3806 [varies] Sets the resolver's
3807 retransmission time interval (in
3808 seconds) for the first attempt to
3810 confTO_RESOLVER_RETRANS_NORMAL Timeout.resolver.retrans.normal
3811 [varies] Sets the resolver's
3812 retransmission time interval (in
3813 seconds) for all resolver lookups
3814 except the first delivery attempt.
3815 confTO_RESOLVER_RETRY Timeout.resolver.retry
3816 [varies] Sets the number of times
3817 to retransmit a resolver query.
3819 Timeout.resolver.retry.first and
3820 Timeout.resolver.retry.normal.
3821 confTO_RESOLVER_RETRY_FIRST Timeout.resolver.retry.first
3822 [varies] Sets the number of times
3823 to retransmit a resolver query for
3824 the first attempt to deliver a
3826 confTO_RESOLVER_RETRY_NORMAL Timeout.resolver.retry.normal
3827 [varies] Sets the number of times
3828 to retransmit a resolver query for
3829 all resolver lookups except the
3830 first delivery attempt.
3831 confTIME_ZONE TimeZoneSpec [USE_SYSTEM] Time zone info -- can be
3832 USE_SYSTEM to use the system's idea,
3833 USE_TZ to use the user's TZ envariable,
3834 or something else to force that value.
3835 confDEF_USER_ID DefaultUser [1:1] Default user id.
3836 confUSERDB_SPEC UserDatabaseSpec
3837 [undefined] User database
3839 confFALLBACK_MX FallbackMXhost [undefined] Fallback MX host.
3840 confFALLBACK_SMARTHOST FallbackSmartHost
3841 [undefined] Fallback smart host.
3842 confTRY_NULL_MX_LIST TryNullMXList [False] If this host is the best MX
3843 for a host and other arrangements
3844 haven't been made, try connecting
3845 to the host directly; normally this
3846 would be a config error.
3847 confQUEUE_LA QueueLA [varies] Load average at which
3848 queue-only function kicks in.
3849 Default values is (8 * numproc)
3850 where numproc is the number of
3851 processors online (if that can be
3853 confREFUSE_LA RefuseLA [varies] Load average at which
3854 incoming SMTP connections are
3855 refused. Default values is (12 *
3856 numproc) where numproc is the
3857 number of processors online (if
3858 that can be determined).
3859 confREJECT_LOG_INTERVAL RejectLogInterval [3h] Log interval when
3860 refusing connections for this long.
3861 confDELAY_LA DelayLA [0] Load average at which sendmail
3862 will sleep for one second on most
3863 SMTP commands and before accepting
3864 connections. 0 means no limit.
3865 confMAX_ALIAS_RECURSION MaxAliasRecursion
3866 [10] Maximum depth of alias recursion.
3867 confMAX_DAEMON_CHILDREN MaxDaemonChildren
3868 [undefined] The maximum number of
3869 children the daemon will permit. After
3870 this number, connections will be
3871 rejected. If not set or <= 0, there is
3873 confMAX_HEADERS_LENGTH MaxHeadersLength
3874 [32768] Maximum length of the sum
3876 confMAX_MIME_HEADER_LENGTH MaxMimeHeaderLength
3877 [undefined] Maximum length of
3878 certain MIME header field values.
3879 confCONNECTION_RATE_THROTTLE ConnectionRateThrottle
3880 [undefined] The maximum number of
3881 connections permitted per second per
3882 daemon. After this many connections
3883 are accepted, further connections
3884 will be delayed. If not set or <= 0,
3886 confCONNECTION_RATE_WINDOW_SIZE ConnectionRateWindowSize
3887 [60s] Define the length of the
3888 interval for which the number of
3889 incoming connections is maintained.
3890 confWORK_RECIPIENT_FACTOR
3891 RecipientFactor [30000] Cost of each recipient.
3892 confSEPARATE_PROC ForkEachJob [False] Run all deliveries in a
3894 confWORK_CLASS_FACTOR ClassFactor [1800] Priority multiplier for class.
3895 confWORK_TIME_FACTOR RetryFactor [90000] Cost of each delivery attempt.
3896 confQUEUE_SORT_ORDER QueueSortOrder [Priority] Queue sort algorithm:
3897 Priority, Host, Filename, Random,
3898 Modification, or Time.
3899 confMIN_QUEUE_AGE MinQueueAge [0] The minimum amount of time a job
3900 must sit in the queue between queue
3901 runs. This allows you to set the
3902 queue run interval low for better
3903 responsiveness without trying all
3905 confDEF_CHAR_SET DefaultCharSet [unknown-8bit] When converting
3906 unlabeled 8 bit input to MIME, the
3907 character set to use by default.
3908 confSERVICE_SWITCH_FILE ServiceSwitchFile
3909 [/etc/mail/service.switch] The file
3910 to use for the service switch on
3911 systems that do not have a
3912 system-defined switch.
3913 confHOSTS_FILE HostsFile [/etc/hosts] The file to use when doing
3914 "file" type access of hosts names.
3915 confDIAL_DELAY DialDelay [0s] If a connection fails, wait this
3916 long and try again. Zero means "don't
3917 retry". This is to allow "dial on
3918 demand" connections to have enough time
3919 to complete a connection.
3920 confNO_RCPT_ACTION NoRecipientAction
3921 [none] What to do if there are no legal
3922 recipient fields (To:, Cc: or Bcc:)
3923 in the message. Legal values can
3924 be "none" to just leave the
3925 nonconforming message as is, "add-to"
3926 to add a To: header with all the
3927 known recipients (which may expose
3928 blind recipients), "add-apparently-to"
3929 to do the same but use Apparently-To:
3930 instead of To: (strongly discouraged
3931 in accordance with IETF standards),
3932 "add-bcc" to add an empty Bcc:
3933 header, or "add-to-undisclosed" to
3935 ``To: undisclosed-recipients:;''.
3936 confSAFE_FILE_ENV SafeFileEnvironment
3937 [undefined] If set, sendmail will do a
3938 chroot() into this directory before
3940 confCOLON_OK_IN_ADDR ColonOkInAddr [True unless Configuration Level > 6]
3941 If set, colons are treated as a regular
3942 character in addresses. If not set,
3943 they are treated as the introducer to
3944 the RFC 822 "group" syntax. Colons are
3945 handled properly in route-addrs. This
3946 option defaults on for V5 and lower
3947 configuration files.
3948 confMAX_QUEUE_RUN_SIZE MaxQueueRunSize [0] If set, limit the maximum size of
3949 any given queue run to this number of
3950 entries. Essentially, this will stop
3951 reading each queue directory after this
3952 number of entries are reached; it does
3953 _not_ pick the highest priority jobs,
3954 so this should be as large as your
3955 system can tolerate. If not set, there
3957 confMAX_QUEUE_CHILDREN MaxQueueChildren
3958 [undefined] Limits the maximum number
3959 of concurrent queue runners active.
3960 This is to keep system resources used
3961 within a reasonable limit. Relates to
3962 Queue Groups and ForkEachJob.
3963 confMAX_RUNNERS_PER_QUEUE MaxRunnersPerQueue
3964 [1] Only active when MaxQueueChildren
3965 defined. Controls the maximum number
3966 of queue runners (aka queue children)
3967 active at the same time in a work
3968 group. See also MaxQueueChildren.
3969 confDONT_EXPAND_CNAMES DontExpandCnames
3970 [False] If set, $[ ... $] lookups that
3971 do DNS based lookups do not expand
3972 CNAME records. This currently violates
3973 the published standards, but the IETF
3974 seems to be moving toward legalizing
3975 this. For example, if "FTP.Foo.ORG"
3976 is a CNAME for "Cruft.Foo.ORG", then
3977 with this option set a lookup of
3978 "FTP" will return "FTP.Foo.ORG"; if
3979 clear it returns "Cruft.FOO.ORG". N.B.
3980 you may not see any effect until your
3981 downstream neighbors stop doing CNAME
3983 confFROM_LINE UnixFromLine [From $g $d] The From_ line used
3984 when sending to files or programs.
3985 confSINGLE_LINE_FROM_HEADER SingleLineFromHeader
3986 [False] From: lines that have
3987 embedded newlines are unwrapped
3989 confALLOW_BOGUS_HELO AllowBogusHELO [False] Allow HELO SMTP command that
3990 does not include a host name.
3991 confMUST_QUOTE_CHARS MustQuoteChars [.'] Characters to be quoted in a full
3992 name phrase (@,;:\()[] are automatic).
3993 confOPERATORS OperatorChars [.:%@!^/[]+] Address operator
3995 confSMTP_LOGIN_MSG SmtpGreetingMessage
3996 [$j Sendmail $v/$Z; $b]
3997 The initial (spontaneous) SMTP
3998 greeting message. The word "ESMTP"
3999 will be inserted between the first and
4000 second words to convince other
4001 sendmails to try to speak ESMTP.
4002 confDONT_INIT_GROUPS DontInitGroups [False] If set, the initgroups(3)
4003 routine will never be invoked. You
4004 might want to do this if you are
4005 running NIS and you have a large group
4006 map, since this call does a sequential
4007 scan of the map; in a large site this
4008 can cause your ypserv to run
4009 essentially full time. If you set
4010 this, agents run on behalf of users
4011 will only have their primary
4012 (/etc/passwd) group permissions.
4013 confUNSAFE_GROUP_WRITES UnsafeGroupWrites
4014 [False] If set, group-writable
4015 :include: and .forward files are
4016 considered "unsafe", that is, programs
4017 and files cannot be directly referenced
4018 from such files. World-writable files
4019 are always considered unsafe.
4020 confCONNECT_ONLY_TO ConnectOnlyTo [undefined] override connection
4021 address (for testing).
4022 confCONTROL_SOCKET_NAME ControlSocketName
4023 [undefined] Control socket for daemon
4025 confDOUBLE_BOUNCE_ADDRESS DoubleBounceAddress
4026 [postmaster] If an error occurs when
4027 sending an error message, send that
4028 "double bounce" error message to this
4029 address. If it expands to an empty
4030 string, double bounces are dropped.
4031 confDEAD_LETTER_DROP DeadLetterDrop [undefined] Filename to save bounce
4032 messages which could not be returned
4033 to the user or sent to postmaster.
4034 If not set, the queue file will
4036 confRRT_IMPLIES_DSN RrtImpliesDsn [False] Return-Receipt-To: header
4037 implies DSN request.
4038 confRUN_AS_USER RunAsUser [undefined] If set, become this user
4039 when reading and delivering mail.
4040 Causes all file reads (e.g., .forward
4041 and :include: files) to be done as
4042 this user. Also, all programs will
4043 be run as this user, and all output
4044 files will be written as this user.
4045 confMAX_RCPTS_PER_MESSAGE MaxRecipientsPerMessage
4046 [infinite] If set, allow no more than
4047 the specified number of recipients in
4048 an SMTP envelope. Further recipients
4049 receive a 452 error code (i.e., they
4050 are deferred for the next delivery
4052 confBAD_RCPT_THROTTLE BadRcptThrottle [infinite] If set and the specified
4053 number of recipients in a single SMTP
4054 transaction have been rejected, sleep
4055 for one second after each subsequent
4056 RCPT command in that transaction.
4057 confDONT_PROBE_INTERFACES DontProbeInterfaces
4058 [False] If set, sendmail will _not_
4059 insert the names and addresses of any
4060 local interfaces into class {w}
4061 (list of known "equivalent" addresses).
4062 If you set this, you must also include
4063 some support for these addresses (e.g.,
4064 in a mailertable entry) -- otherwise,
4065 mail to addresses in this list will
4066 bounce with a configuration error.
4067 If set to "loopback" (without
4068 quotes), sendmail will skip
4069 loopback interfaces (e.g., "lo0").
4070 confPID_FILE PidFile [system dependent] Location of pid
4072 confPROCESS_TITLE_PREFIX ProcessTitlePrefix
4073 [undefined] Prefix string for the
4074 process title shown on 'ps' listings.
4075 confDONT_BLAME_SENDMAIL DontBlameSendmail
4076 [safe] Override sendmail's file
4077 safety checks. This will definitely
4078 compromise system security and should
4079 not be used unless absolutely
4081 confREJECT_MSG - [550 Access denied] The message
4082 given if the access database contains
4083 REJECT in the value portion.
4084 confRELAY_MSG - [550 Relaying denied] The message
4085 given if an unauthorized relaying
4086 attempt is rejected.
4087 confDF_BUFFER_SIZE DataFileBufferSize
4088 [4096] The maximum size of a
4089 memory-buffered data (df) file
4090 before a disk-based file is used.
4091 confXF_BUFFER_SIZE XScriptFileBufferSize
4092 [4096] The maximum size of a
4093 memory-buffered transcript (xf)
4094 file before a disk-based file is
4096 confAUTH_MECHANISMS AuthMechanisms [GSSAPI KERBEROS_V4 DIGEST-MD5
4097 CRAM-MD5] List of authentication
4098 mechanisms for AUTH (separated by
4099 spaces). The advertised list of
4100 authentication mechanisms will be the
4101 intersection of this list and the list
4102 of available mechanisms as determined
4103 by the Cyrus SASL library.
4104 confAUTH_REALM AuthRealm [undefined] The authentication realm
4105 that is passed to the Cyrus SASL
4106 library. If no realm is specified,
4108 confDEF_AUTH_INFO DefaultAuthInfo [undefined] Name of file that contains
4109 authentication information for
4110 outgoing connections. This file must
4111 contain the user id, the authorization
4112 id, the password (plain text), the
4113 realm to use, and the list of
4114 mechanisms to try, each on a separate
4115 line and must be readable by root (or
4116 the trusted user) only. If no realm
4117 is specified, $j is used. If no
4118 mechanisms are given in the file,
4119 AuthMechanisms is used. Notice: this
4120 option is deprecated and will be
4121 removed in future versions; it doesn't
4122 work for the MSP since it can't read
4123 the file. Use the authinfo ruleset
4124 instead. See also the section SMTP
4126 confAUTH_OPTIONS AuthOptions [undefined] If this option is 'A'
4127 then the AUTH= parameter for the
4128 MAIL FROM command is only issued
4129 when authentication succeeded.
4130 See doc/op/op.me for more options
4132 confAUTH_MAX_BITS AuthMaxBits [INT_MAX] Limit the maximum encryption
4133 strength for the security layer in
4134 SMTP AUTH (SASL). Default is
4135 essentially unlimited.
4136 confTLS_SRV_OPTIONS TLSSrvOptions If this option is 'V' no client
4137 verification is performed, i.e.,
4138 the server doesn't ask for a
4140 confLDAP_DEFAULT_SPEC LDAPDefaultSpec [undefined] Default map
4141 specification for LDAP maps. The
4142 value should only contain LDAP
4143 specific settings such as "-h host
4144 -p port -d bindDN", etc. The
4145 settings will be used for all LDAP
4146 maps unless they are specified in
4147 the individual map specification
4149 confCACERT_PATH CACertPath [undefined] Path to directory
4151 confCACERT CACertFile [undefined] File containing one CA
4153 confSERVER_CERT ServerCertFile [undefined] File containing the
4154 cert of the server, i.e., this cert
4155 is used when sendmail acts as
4157 confSERVER_KEY ServerKeyFile [undefined] File containing the
4158 private key belonging to the server
4160 confCLIENT_CERT ClientCertFile [undefined] File containing the
4161 cert of the client, i.e., this cert
4162 is used when sendmail acts as
4164 confCLIENT_KEY ClientKeyFile [undefined] File containing the
4165 private key belonging to the client
4167 confCRL CRLFile [undefined] File containing certificate
4168 revocation status, useful for X.509v3
4169 authentication. Note that CRL requires
4170 at least OpenSSL version 0.9.7.
4171 confDH_PARAMETERS DHParameters [undefined] File containing the
4173 confRAND_FILE RandFile [undefined] File containing random
4174 data (use prefix file:) or the
4175 name of the UNIX socket if EGD is
4176 used (use prefix egd:). STARTTLS
4177 requires this option if the compile
4178 flag HASURANDOM is not set (see
4180 confNICE_QUEUE_RUN NiceQueueRun [undefined] If set, the priority of
4181 queue runners is set the given value
4183 confDIRECT_SUBMISSION_MODIFIERS DirectSubmissionModifiers
4184 [undefined] Defines {daemon_flags}
4185 for direct submissions.
4186 confUSE_MSP UseMSP [false] Use as mail submission
4187 program, see sendmail/SECURITY.
4188 confDELIVER_BY_MIN DeliverByMin [0] Minimum time for Deliver By
4189 SMTP Service Extension (RFC 2852).
4190 confREQUIRES_DIR_FSYNC RequiresDirfsync [true] RequiresDirfsync can
4191 be used to turn off the compile time
4192 flag REQUIRES_DIR_FSYNC at runtime.
4193 See sendmail/README for details.
4194 confSHARED_MEMORY_KEY SharedMemoryKey [0] Key for shared memory.
4195 confFAST_SPLIT FastSplit [1] If set to a value greater than
4196 zero, the initial MX lookups on
4197 addresses is suppressed when they
4198 are sorted which may result in
4199 faster envelope splitting. If the
4200 mail is submitted directly from the
4201 command line, then the value also
4202 limits the number of processes to
4203 deliver the envelopes.
4204 confMAILBOX_DATABASE MailboxDatabase [pw] Type of lookup to find
4205 information about local mailboxes.
4206 confDEQUOTE_OPTS - [empty] Additional options for the
4208 confINPUT_MAIL_FILTERS InputMailFilters
4209 A comma separated list of filters
4210 which determines which filters and
4211 the invocation sequence are
4212 contacted for incoming SMTP
4213 messages. If none are set, no
4214 filters will be contacted.
4215 confMILTER_LOG_LEVEL Milter.LogLevel [9] Log level for input mail filter
4216 actions, defaults to LogLevel.
4217 confMILTER_MACROS_CONNECT Milter.macros.connect
4218 [j, _, {daemon_name}, {if_name},
4219 {if_addr}] Macros to transmit to
4220 milters when a session connection
4222 confMILTER_MACROS_HELO Milter.macros.helo
4223 [{tls_version}, {cipher},
4224 {cipher_bits}, {cert_subject},
4225 {cert_issuer}] Macros to transmit to
4226 milters after HELO/EHLO command.
4227 confMILTER_MACROS_ENVFROM Milter.macros.envfrom
4228 [i, {auth_type}, {auth_authen},
4229 {auth_ssf}, {auth_author},
4230 {mail_mailer}, {mail_host},
4231 {mail_addr}] Macros to transmit to
4232 milters after MAIL FROM command.
4233 confMILTER_MACROS_ENVRCPT Milter.macros.envrcpt
4234 [{rcpt_mailer}, {rcpt_host},
4235 {rcpt_addr}] Macros to transmit to
4236 milters after RCPT TO command.
4237 confMILTER_MACROS_EOM Milter.macros.eom
4238 [{msg_id}] Macros to transmit to
4239 milters after DATA command.
4242 See also the description of OSTYPE for some parameters that can be
4243 tweaked (generally pathnames to mailers).
4245 ClientPortOptions and DaemonPortOptions are special cases since multiple
4246 clients/daemons can be defined. This can be done via
4248 CLIENT_OPTIONS(`field1=value1,field2=value2,...')
4249 DAEMON_OPTIONS(`field1=value1,field2=value2,...')
4251 Note that multiple CLIENT_OPTIONS() commands (and therefore multiple
4252 ClientPortOptions settings) are allowed in order to give settings for each
4253 protocol family (e.g., one for Family=inet and one for Family=inet6). A
4254 restriction placed on one family only affects outgoing connections on that
4257 If DAEMON_OPTIONS is not used, then the default is
4259 DAEMON_OPTIONS(`Port=smtp, Name=MTA')
4260 DAEMON_OPTIONS(`Port=587, Name=MSA, M=E')
4262 If you use one DAEMON_OPTIONS macro, it will alter the parameters
4263 of the first of these. The second will still be defaulted; it
4264 represents a "Message Submission Agent" (MSA) as defined by RFC
4265 2476 (see below). To turn off the default definition for the MSA,
4266 use FEATURE(`no_default_msa') (see also FEATURES). If you use
4267 additional DAEMON_OPTIONS macros, they will add additional daemons.
4269 Example 1: To change the port for the SMTP listener, while
4270 still using the MSA default, use
4271 DAEMON_OPTIONS(`Port=925, Name=MTA')
4273 Example 2: To change the port for the MSA daemon, while still
4274 using the default SMTP port, use
4275 FEATURE(`no_default_msa')
4276 DAEMON_OPTIONS(`Name=MTA')
4277 DAEMON_OPTIONS(`Port=987, Name=MSA, M=E')
4279 Note that if the first of those DAEMON_OPTIONS lines were omitted, then
4280 there would be no listener on the standard SMTP port.
4282 Example 3: To listen on both IPv4 and IPv6 interfaces, use
4284 DAEMON_OPTIONS(`Name=MTA-v4, Family=inet')
4285 DAEMON_OPTIONS(`Name=MTA-v6, Family=inet6')
4287 A "Message Submission Agent" still uses all of the same rulesets for
4288 processing the message (and therefore still allows message rejection via
4289 the check_* rulesets). In accordance with the RFC, the MSA will ensure
4290 that all domains in envelope addresses are fully qualified if the message
4291 is relayed to another MTA. It will also enforce the normal address syntax
4292 rules and log error messages. Additionally, by using the M=a modifier you
4293 can require authentication before messages are accepted by the MSA.
4294 Notice: Do NOT use the 'a' modifier on a public accessible MTA! Finally,
4295 the M=E modifier shown above disables ETRN as required by RFC 2476.
4297 Mail filters can be defined using the INPUT_MAIL_FILTER() and MAIL_FILTER()
4300 INPUT_MAIL_FILTER(`sample', `S=local:/var/run/f1.sock')
4301 MAIL_FILTER(`myfilter', `S=inet:3333@localhost')
4303 The INPUT_MAIL_FILTER() command causes the filter(s) to be called in the
4304 same order they were specified by also setting confINPUT_MAIL_FILTERS. A
4305 filter can be defined without adding it to the input filter list by using
4306 MAIL_FILTER() instead of INPUT_MAIL_FILTER() in your .mc file.
4307 Alternatively, you can reset the list of filters and their order by setting
4308 confINPUT_MAIL_FILTERS option after all INPUT_MAIL_FILTER() commands in
4312 +----------------------------+
4313 | MESSAGE SUBMISSION PROGRAM |
4314 +----------------------------+
4316 The purpose of the message submission program (MSP) is explained
4317 in sendmail/SECURITY. This section contains a list of caveats and
4318 a few hints how for those who want to tweak the default configuration
4319 for it (which is installed as submit.cf).
4321 Notice: do not add options/features to submit.mc unless you are
4322 absolutely sure you need them. Options you may want to change
4325 - confTRUSTED_USERS, FEATURE(`use_ct_file'), and confCT_FILE for
4326 avoiding X-Authentication warnings.
4327 - confTIME_ZONE to change it from the default `USE_TZ'.
4328 - confDELIVERY_MODE is set to interactive in msp.m4 instead
4329 of the default background mode.
4330 - FEATURE(stickyhost) and LOCAL_RELAY to send unqualified addresses
4331 to the LOCAL_RELAY instead of the default relay.
4332 - confRAND_FILE if you use STARTTLS and sendmail is not compiled with
4333 the flag HASURANDOM.
4335 The MSP performs hostname canonicalization by default. As also
4336 explained in sendmail/SECURITY, mail may end up for various DNS
4337 related reasons in the MSP queue. This problem can be minimized by
4340 FEATURE(`nocanonify', `canonify_hosts')
4341 define(`confDIRECT_SUBMISSION_MODIFIERS', `C')
4343 See the discussion about nocanonify for possible side effects.
4345 Some things are not intended to work with the MSP. These include
4346 features that influence the delivery process (e.g., mailertable,
4347 aliases), or those that are only important for a SMTP server (e.g.,
4348 virtusertable, DaemonPortOptions, multiple queues). Moreover,
4349 relaxing certain restrictions (RestrictQueueRun, permissions on
4350 queue directory) or adding features (e.g., enabling prog/file mailer)
4351 can cause security problems.
4353 Other things don't work well with the MSP and require tweaking or
4354 workarounds. For example, to allow for client authentication it
4355 is not just sufficient to provide a client certificate and the
4356 corresponding key, but it is also necessary to make the key group
4357 (smmsp) readable and tell sendmail not to complain about that, i.e.,
4359 define(`confDONT_BLAME_SENDMAIL', `GroupReadableKeyFile')
4361 If the MSP should actually use AUTH then the necessary data
4362 should be placed in a map as explained in SMTP AUTHENTICATION:
4364 FEATURE(`authinfo', `DATABASE_MAP_TYPE /etc/mail/msp-authinfo')
4366 /etc/mail/msp-authinfo should contain an entry like:
4368 AuthInfo:127.0.0.1 "U:smmsp" "P:secret" "M:DIGEST-MD5"
4370 The file and the map created by makemap should be owned by smmsp,
4371 its group should be smmsp, and it should have mode 640. The database
4372 used by the MTA for AUTH must have a corresponding entry.
4373 Additionally the MTA must trust this authentication data so the AUTH=
4374 part will be relayed on to the next hop. This can be achieved by
4375 adding the following to your sendmail.mc file:
4379 R$* $: $&{auth_authen}
4382 Note: the authentication data can leak to local users who invoke
4383 the MSP with debug options or even with -v. For that reason either
4384 an authentication mechanism that does not show the password in the
4385 AUTH dialogue (e.g., DIGEST-MD5) or a different authentication
4386 method like STARTTLS should be used.
4388 feature/msp.m4 defines almost all settings for the MSP. Most of
4389 those should not be changed at all. Some of the features and options
4390 can be overridden if really necessary. It is a bit tricky to do
4391 this, because it depends on the actual way the option is defined
4392 in feature/msp.m4. If it is directly defined (i.e., define()) then
4393 the modified value must be defined after
4397 If it is conditionally defined (i.e., ifdef()) then the desired
4398 value must be defined before the FEATURE line in the .mc file.
4399 To see how the options are defined read feature/msp.m4.
4402 +--------------------------+
4403 | FORMAT OF FILES AND MAPS |
4404 +--------------------------+
4406 Files that define classes, i.e., F{classname}, consist of lines
4407 each of which contains a single element of the class. For example,
4408 /etc/mail/local-host-names may have the following content:
4413 Maps must be created using makemap(8) , e.g.,
4415 makemap hash MAP < MAP
4417 In general, a text file from which a map is created contains lines
4422 where 'key' and 'value' are also called LHS and RHS, respectively.
4423 By default, the delimiter between LHS and RHS is a non-empty sequence
4424 of white space characters.
4427 +------------------+
4428 | DIRECTORY LAYOUT |
4429 +------------------+
4431 Within this directory are several subdirectories, to wit:
4433 m4 General support routines. These are typically
4434 very important and should not be changed without
4435 very careful consideration.
4437 cf The configuration files themselves. They have
4438 ".mc" suffixes, and must be run through m4 to
4439 become complete. The resulting output should
4440 have a ".cf" suffix.
4442 ostype Definitions describing a particular operating
4443 system type. These should always be referenced
4444 using the OSTYPE macro in the .mc file. Examples
4445 include "bsd4.3", "bsd4.4", "sunos3.5", and
4448 domain Definitions describing a particular domain, referenced
4449 using the DOMAIN macro in the .mc file. These are
4450 site dependent; for example, "CS.Berkeley.EDU.m4"
4451 describes hosts in the CS.Berkeley.EDU subdomain.
4453 mailer Descriptions of mailers. These are referenced using
4454 the MAILER macro in the .mc file.
4456 sh Shell files used when building the .cf file from the
4457 .mc file in the cf subdirectory.
4459 feature These hold special orthogonal features that you might
4460 want to include. They should be referenced using
4463 hack Local hacks. These can be referenced using the HACK
4464 macro. They shouldn't be of more than voyeuristic
4465 interest outside the .Berkeley.EDU domain, but who knows?
4467 siteconfig Site configuration -- e.g., tables of locally connected
4471 +------------------------+
4472 | ADMINISTRATIVE DETAILS |
4473 +------------------------+
4475 The following sections detail usage of certain internal parts of the
4476 sendmail.cf file. Read them carefully if you are trying to modify
4477 the current model. If you find the above descriptions adequate, these
4478 should be {boring, confusing, tedious, ridiculous} (pick one or more).
4480 RULESETS (* means built in to sendmail)
4483 1 * Sender rewriting
4484 2 * Recipient rewriting
4485 3 * Canonicalization
4487 5 * Local address rewrite (after aliasing)
4488 1x mailer rules (sender qualification)
4489 2x mailer rules (recipient qualification)
4490 3x mailer rules (sender header qualification)
4491 4x mailer rules (recipient header qualification)
4492 5x mailer subroutines (general)
4493 6x mailer subroutines (general)
4494 7x mailer subroutines (general)
4496 90 Mailertable host stripping
4497 96 Bottom half of Ruleset 3 (ruleset 6 in old sendmail)
4498 97 Hook for recursive ruleset 0 call (ruleset 7 in old sendmail)
4499 98 Local part of ruleset 0 (ruleset 8 in old sendmail)
4504 0 local, prog local and program mailers
4505 1 [e]smtp, relay SMTP channel
4506 2 uucp-* UNIX-to-UNIX Copy Program
4507 3 netnews Network News delivery
4508 4 fax Sam Leffler's HylaFAX software
4509 5 mail11 DECnet mailer
4517 D The local domain -- usually not needed
4518 E reserved for X.400 Relay
4521 H mail Hub (for mail clusters)
4526 M Masquerade (who you claim to be)
4531 R Relay (for unqualified names)
4534 U my UUCP name (if you have a UUCP connection)
4535 V UUCP Relay (class {V} hosts)
4536 W UUCP Relay (class {W} hosts)
4537 X UUCP Relay (class {X} hosts)
4538 Y UUCP Relay (all other hosts)
4545 B domains that are candidates for bestmx lookup
4548 E addresses that should not seem to come from $M
4549 F hosts this system forward for
4550 G domains that should be looked up in genericstable
4555 L addresses that should not be forwarded to $R
4556 M domains that should be mapped to $M
4557 N host/domains that should not be mapped to $M
4558 O operators that indicate network operations (cannot be in local names)
4559 P top level pseudo-domains: BITNET, DECNET, FAX, UUCP, etc.
4561 R domains this system is willing to relay (pass anti-spam filters)
4564 U locally connected UUCP hosts
4565 V UUCP hosts connected to relay $V
4566 W UUCP hosts connected to relay $W
4567 X UUCP hosts connected to relay $X
4568 Y locally connected smart UUCP hosts
4569 Z locally connected domain-ized UUCP hosts
4570 . the class containing only a dot
4571 [ the class containing only a left bracket
4576 1 Local host detection and resolution
4577 2 Local Ruleset 3 additions
4578 3 Local Ruleset 0 additions
4579 4 UUCP Ruleset 0 additions
4580 5 locally interpreted names (overrides $R)
4581 6 local configuration (at top of file)
4582 7 mailer definitions
4583 8 DNS based blacklists
4584 9 special local rulesets (1 and 2)
4586 $Revision: 8.694 $, Last updated $Date: 2005/03/23 21:41:09 $