Docs: warn against using $local_part directly in delivery
[exim.git] / src / src / configure.default
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1######################################################################
2# Runtime configuration file for Exim #
3######################################################################
4
5
6# This is a default configuration file which will operate correctly in
7# uncomplicated installations. Please see the manual for a complete list
8# of all the runtime configuration options that can be included in a
9# configuration file. There are many more than are mentioned here. The
10# manual is in the file doc/spec.txt in the Exim distribution as a plain
11# ASCII file. Other formats (PostScript, Texinfo, HTML, PDF) are available
20f0f788 12# from the Exim ftp sites. The manual is also online at the Exim website.
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13
14
15# This file is divided into several parts, all but the first of which are
16# headed by a line starting with the word "begin". Only those parts that
17# are required need to be present. Blank lines, and lines starting with #
18# are ignored.
19
20
21########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ###########
22# #
23# Whenever you change Exim's configuration file, you *must* remember to #
24# HUP the Exim daemon, because it will not pick up the new configuration #
25# until you do. However, any other Exim processes that are started, for #
26# example, a process started by an MUA in order to send a message, will #
27# see the new configuration as soon as it is in place. #
28# #
29# You do not need to HUP the daemon for changes in auxiliary files that #
30# are referenced from this file. They are read every time they are used. #
31# #
32# It is usually a good idea to test a new configuration for syntactic #
33# correctness before installing it (for example, by running the command #
34# "exim -C /config/file.new -bV"). #
35# #
36########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ###########
37
38
39
40######################################################################
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41# MACROS #
42######################################################################
43#
44
45# If you want to use a smarthost instead of sending directly to recipient
46# domains, uncomment this macro definition and set a real hostname.
47# An appropriately privileged user can then redirect email on the command-line
48# in emergencies, via -D.
49#
50# ROUTER_SMARTHOST=MAIL.HOSTNAME.FOR.CENTRAL.SERVER.EXAMPLE
51
52######################################################################
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53# MAIN CONFIGURATION SETTINGS #
54######################################################################
f26587cb 55#
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56
57# Specify your host's canonical name here. This should normally be the fully
58# qualified "official" name of your host. If this option is not set, the
59# uname() function is called to obtain the name. In many cases this does
60# the right thing and you need not set anything explicitly.
61
62# primary_hostname =
63
64
65# The next three settings create two lists of domains and one list of hosts.
66# These lists are referred to later in this configuration using the syntax
67# +local_domains, +relay_to_domains, and +relay_from_hosts, respectively. They
68# are all colon-separated lists:
69
70domainlist local_domains = @
71domainlist relay_to_domains =
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72hostlist relay_from_hosts = localhost
73# (We rely upon hostname resolution working for localhost, because the default
74# uncommented configuration needs to work in IPv4-only environments.)
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75
76# Most straightforward access control requirements can be obtained by
53394084 77# appropriate settings of the above options. In more complicated situations,
92db8b2d 78# you may need to modify the Access Control Lists (ACLs) which appear later in
53394084 79# this file.
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80
81# The first setting specifies your local domains, for example:
82#
83# domainlist local_domains = my.first.domain : my.second.domain
84#
85# You can use "@" to mean "the name of the local host", as in the default
86# setting above. This is the name that is specified by primary_hostname,
87# as specified above (or defaulted). If you do not want to do any local
88# deliveries, remove the "@" from the setting above. If you want to accept mail
89# addressed to your host's literal IP address, for example, mail addressed to
90# "user@[192.168.23.44]", you can add "@[]" as an item in the local domains
91# list. You also need to uncomment "allow_domain_literals" below. This is not
92# recommended for today's Internet.
93
94# The second setting specifies domains for which your host is an incoming relay.
95# If you are not doing any relaying, you should leave the list empty. However,
96# if your host is an MX backup or gateway of some kind for some domains, you
97# must set relay_to_domains to match those domains. For example:
98#
99# domainlist relay_to_domains = *.myco.com : my.friend.org
100#
101# This will allow any host to relay through your host to those domains.
102# See the section of the manual entitled "Control of relaying" for more
103# information.
104
105# The third setting specifies hosts that can use your host as an outgoing relay
106# to any other host on the Internet. Such a setting commonly refers to a
107# complete local network as well as the localhost. For example:
108#
ff284120 109# hostlist relay_from_hosts = <; 127.0.0.1 ; ::1 ; 192.168.0.0/16
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110#
111# The "/16" is a bit mask (CIDR notation), not a number of hosts. Note that you
112# have to include 127.0.0.1 if you want to allow processes on your host to send
113# SMTP mail by using the loopback address. A number of MUAs use this method of
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114# sending mail. Often, connections are made to "localhost", which might be ::1
115# on IPv6-enabled hosts. Do not forget CIDR for your IPv6 networks.
059ec3d9 116
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117# All three of these lists may contain many different kinds of item, including
118# wildcarded names, regular expressions, and file lookups. See the reference
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119# manual for details. The lists above are used in the access control lists for
120# checking incoming messages. The names of these ACLs are defined here:
059ec3d9 121
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122acl_smtp_rcpt = acl_check_rcpt
123.ifdef _HAVE_PRDR
124acl_smtp_data_prdr = acl_check_prdr
125.endif
126acl_smtp_data = acl_check_data
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127
128# You should not change those settings until you understand how ACLs work.
129
130
131# If you are running a version of Exim that was compiled with the content-
132# scanning extension, you can cause incoming messages to be automatically
133# scanned for viruses. You have to modify the configuration in two places to
134# set this up. The first of them is here, where you define the interface to
135# your scanner. This example is typical for ClamAV; see the manual for details
136# of what to set for other virus scanners. The second modification is in the
137# acl_check_data access control list (see below).
059ec3d9 138
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139# av_scanner = clamd:/tmp/clamd
140
141
142# For spam scanning, there is a similar option that defines the interface to
143# SpamAssassin. You do not need to set this if you are using the default, which
144# is shown in this commented example. As for virus scanning, you must also
145# modify the acl_check_data access control list to enable spam scanning.
146
147# spamd_address = 127.0.0.1 783
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148
149
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150# If Exim is compiled with support for TLS, you may want to enable the
151# following options so that Exim allows clients to make encrypted
152# connections. In the authenticators section below, there are template
153# configurations for plaintext username/password authentication. This kind
154# of authentication is only safe when used within a TLS connection, so the
155# authenticators will only work if the following TLS settings are turned on
156# as well.
157
158# Allow any client to use TLS.
159
160# tls_advertise_hosts = *
161
162# Specify the location of the Exim server's TLS certificate and private key.
163# The private key must not be encrypted (password protected). You can put
164# the certificate and private key in the same file, in which case you only
165# need the first setting, or in separate files, in which case you need both
166# options.
167
168# tls_certificate = /etc/ssl/exim.crt
169# tls_privatekey = /etc/ssl/exim.pem
170
ba86e143 171# For OpenSSL, prefer EC- over RSA-authenticated ciphers
1fa62f99 172# tls_require_ciphers = ECDSA:RSA:!COMPLEMENTOFDEFAULT
ba86e143 173
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174# In order to support roaming users who wish to send email from anywhere,
175# you may want to make Exim listen on other ports as well as port 25, in
176# case these users need to send email from a network that blocks port 25.
177# The standard port for this purpose is port 587, the "message submission"
178# port. See RFC 4409 for details. Microsoft MUAs cannot be configured to
179# talk the message submission protocol correctly, so if you need to support
180# them you should also allow TLS-on-connect on the traditional but
181# non-standard port 465.
182
183# daemon_smtp_ports = 25 : 465 : 587
184# tls_on_connect_ports = 465
185
186
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187# Specify the domain you want to be added to all unqualified addresses
188# here. An unqualified address is one that does not contain an "@" character
189# followed by a domain. For example, "caesar@rome.example" is a fully qualified
190# address, but the string "caesar" (i.e. just a login name) is an unqualified
191# email address. Unqualified addresses are accepted only from local callers by
192# default. See the recipient_unqualified_hosts option if you want to permit
193# unqualified addresses from remote sources. If this option is not set, the
194# primary_hostname value is used for qualification.
195
196# qualify_domain =
197
198
199# If you want unqualified recipient addresses to be qualified with a different
200# domain to unqualified sender addresses, specify the recipient domain here.
201# If this option is not set, the qualify_domain value is used.
202
203# qualify_recipient =
204
205
206# The following line must be uncommented if you want Exim to recognize
207# addresses of the form "user@[10.11.12.13]" that is, with a "domain literal"
208# (an IP address) instead of a named domain. The RFCs still require this form,
209# but it makes little sense to permit mail to be sent to specific hosts by
210# their IP address in the modern Internet. This ancient format has been used
211# by those seeking to abuse hosts by using them for unwanted relaying. If you
212# really do want to support domain literals, uncomment the following line, and
213# see also the "domain_literal" router below.
214
215# allow_domain_literals
216
217
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218# No deliveries will ever be run under the uids of users specified by
219# never_users (a colon-separated list). An attempt to do so causes a panic
220# error to be logged, and the delivery to be deferred. This is a paranoic
221# safety catch. There is an even stronger safety catch in the form of the
222# FIXED_NEVER_USERS setting in the configuration for building Exim. The list of
223# users that it specifies is built into the binary, and cannot be changed. The
224# option below just adds additional users to the list. The default for
225# FIXED_NEVER_USERS is "root", but just to be absolutely sure, the default here
226# is also "root".
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227
228# Note that the default setting means you cannot deliver mail addressed to root
229# as if it were a normal user. This isn't usually a problem, as most sites have
230# an alias for root that redirects such mail to a human administrator.
231
232never_users = root
233
234
235# The setting below causes Exim to do a reverse DNS lookup on all incoming
236# IP calls, in order to get the true host name. If you feel this is too
237# expensive, you can specify the networks for which a lookup is done, or
238# remove the setting entirely.
239
240host_lookup = *
241
242
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243# The setting below causes Exim to try to initialize the system resolver
244# library with DNSSEC support. It has no effect if your library lacks
245# DNSSEC support.
246
247dns_dnssec_ok = 1
248
249
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250# The settings below cause Exim to make RFC 1413 (ident) callbacks
251# for all incoming SMTP calls. You can limit the hosts to which these
252# calls are made, and/or change the timeout that is used. If you set
253# the timeout to zero, all RFC 1413 calls are disabled. RFC 1413 calls
254# are cheap and can provide useful information for tracing problem
255# messages, but some hosts and firewalls have problems with them.
256# This can result in a timeout instead of an immediate refused
257# connection, leading to delays on starting up SMTP sessions.
258# (The default was reduced from 30s to 5s for release 4.61. and to
259# disabled for release 4.86)
260#
261#rfc1413_hosts = *
262#rfc1413_query_timeout = 5s
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263
264
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265# Enable an efficiency feature. We advertise the feature; clients
266# may request to use it. For multi-recipient mails we then can
267# reject or accept per-user after the message is received.
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268# This supports recipient-dependent content filtering; without it
269# you have to temp-reject any recipients after the first that have
270# incompatible filtering, and do the filtering in the data ACL.
271# Even with this enabled, you must support the old style for peers
272# not flagging support for PRDR (visible via $prdr_requested).
ff1c79bc 273#
95dfacf2 274.ifdef _HAVE_PRDR
ff1c79bc 275prdr_enable = true
95dfacf2 276.endif
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277
278
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279# By default, Exim expects all envelope addresses to be fully qualified, that
280# is, they must contain both a local part and a domain. If you want to accept
281# unqualified addresses (just a local part) from certain hosts, you can specify
282# these hosts by setting one or both of
283#
284# sender_unqualified_hosts =
285# recipient_unqualified_hosts =
286#
287# to control sender and recipient addresses, respectively. When this is done,
288# unqualified addresses are qualified using the settings of qualify_domain
289# and/or qualify_recipient (see above).
290
291
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292# Unless you run a high-volume site you probably want more logging
293# detail than the default. Adjust to suit.
294
295log_selector = +smtp_protocol_error +smtp_syntax_error \
48162f79 296 +tls_certificate_verified
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297
298
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299# If you want Exim to support the "percent hack" for certain domains,
300# uncomment the following line and provide a list of domains. The "percent
301# hack" is the feature by which mail addressed to x%y@z (where z is one of
302# the domains listed) is locally rerouted to x@y and sent on. If z is not one
303# of the "percent hack" domains, x%y is treated as an ordinary local part. This
304# hack is rarely needed nowadays; you should not enable it unless you are sure
305# that you really need it.
306#
307# percent_hack_domains =
308#
309# As well as setting this option you will also need to remove the test
310# for local parts containing % in the ACL definition below.
311
312
313# When Exim can neither deliver a message nor return it to sender, it "freezes"
314# the delivery error message (aka "bounce message"). There are also other
315# circumstances in which messages get frozen. They will stay on the queue for
316# ever unless one of the following options is set.
317
318# This option unfreezes frozen bounce messages after two days, tries
319# once more to deliver them, and ignores any delivery failures.
320
321ignore_bounce_errors_after = 2d
322
323# This option cancels (removes) frozen messages that are older than a week.
324
325timeout_frozen_after = 7d
326
327
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328# By default, messages that are waiting on Exim's queue are all held in a
329# single directory called "input" which it itself within Exim's spool
330# directory. (The default spool directory is specified when Exim is built, and
331# is often /var/spool/exim/.) Exim works best when its queue is kept short, but
332# there are circumstances where this is not always possible. If you uncomment
333# the setting below, messages on the queue are held in 62 subdirectories of
334# "input" instead of all in the same directory. The subdirectories are called
335# 0, 1, ... A, B, ... a, b, ... z. This has two benefits: (1) If your file
336# system degrades with many files in one directory, this is less likely to
337# happen; (2) Exim can process the queue one subdirectory at a time instead of
338# all at once, which can give better performance with large queues.
339
340# split_spool_directory = true
341
342
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343# If you're in a part of the world where ASCII is not sufficient for most
344# text, then you're probably familiar with RFC2047 message header extensions.
345# By default, Exim adheres to the specification, including a limit of 76
346# characters to a line, with encoded words fitting within a line.
347# If you wish to use decoded headers in message filters in such a way
348# that successful decoding of malformed messages matters, you may wish to
349# configure Exim to be more lenient.
350#
351# check_rfc2047_length = false
352#
353# In particular, the Exim maintainers have had multiple reports of problems
354# from Russian administrators of issues until they disable this check,
355# because of some popular, yet buggy, mail composition software.
356
059ec3d9 357
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358# If you wish to be strictly RFC compliant, or if you know you'll be
359# exchanging email with systems that are not 8-bit clean, then you may
360# wish to disable advertising 8BITMIME. Uncomment this option to do so.
361
362# accept_8bitmime = false
363
364
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365# Exim does not make use of environment variables itself. However,
366# libraries that Exim uses (e.g. LDAP) depend on specific environment settings.
367# There are two lists: keep_environment for the variables we trust, and
368# add_environment for variables we want to set to a specific value.
4c04137d 369# Note that TZ is handled separately by the timezone runtime option
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370# and TIMEZONE_DEFAULT buildtime option.
371
372# keep_environment = ^LDAP
373# add_environment = PATH=/usr/bin::/bin
374
375
376
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377######################################################################
378# ACL CONFIGURATION #
379# Specifies access control lists for incoming SMTP mail #
380######################################################################
381
382begin acl
383
384# This access control list is used for every RCPT command in an incoming
385# SMTP message. The tests are run in order until the address is either
386# accepted or denied.
387
388acl_check_rcpt:
389
390 # Accept if the source is local SMTP (i.e. not over TCP/IP). We do this by
391 # testing for an empty sending host field.
392
393 accept hosts = :
94f85d3e 394 control = dkim_disable_verify
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395
396 #############################################################################
397 # The following section of the ACL is concerned with local parts that contain
398 # @ or % or ! or / or | or dots in unusual places.
399 #
400 # The characters other than dots are rarely found in genuine local parts, but
401 # are often tried by people looking to circumvent relaying restrictions.
402 # Therefore, although they are valid in local parts, these rules lock them
403 # out, as a precaution.
404 #
405 # Empty components (two dots in a row) are not valid in RFC 2822, but Exim
406 # allows them because they have been encountered. (Consider local parts
407 # constructed as "firstinitial.secondinitial.familyname" when applied to
408 # someone like me, who has no second initial.) However, a local part starting
409 # with a dot or containing /../ can cause trouble if it is used as part of a
410 # file name (e.g. for a mailing list). This is also true for local parts that
411 # contain slashes. A pipe symbol can also be troublesome if the local part is
412 # incorporated unthinkingly into a shell command line.
413 #
414 # Two different rules are used. The first one is stricter, and is applied to
415 # messages that are addressed to one of the local domains handled by this
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416 # host. The line "domains = +local_domains" restricts it to domains that are
417 # defined by the "domainlist local_domains" setting above. The rule blocks
418 # local parts that begin with a dot or contain @ % ! / or |. If you have
419 # local accounts that include these characters, you will have to modify this
420 # rule.
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421
422 deny message = Restricted characters in address
423 domains = +local_domains
424 local_parts = ^[.] : ^.*[@%!/|]
425
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426 # The second rule applies to all other domains, and is less strict. The line
427 # "domains = !+local_domains" restricts it to domains that are NOT defined by
428 # the "domainlist local_domains" setting above. The exclamation mark is a
429 # negating operator. This rule allows your own users to send outgoing
430 # messages to sites that use slashes and vertical bars in their local parts.
431 # It blocks local parts that begin with a dot, slash, or vertical bar, but
432 # allows these characters within the local part. However, the sequence /../
433 # is barred. The use of @ % and ! is blocked, as before. The motivation here
434 # is to prevent your users (or your users' viruses) from mounting certain
435 # kinds of attack on remote sites.
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436
437 deny message = Restricted characters in address
438 domains = !+local_domains
439 local_parts = ^[./|] : ^.*[@%!] : ^.*/\\.\\./
440 #############################################################################
441
442 # Accept mail to postmaster in any local domain, regardless of the source,
443 # and without verifying the sender.
444
445 accept local_parts = postmaster
446 domains = +local_domains
447
448 # Deny unless the sender address can be verified.
449
450 require verify = sender
451
5de37277 452 # Accept if the message comes from one of the hosts for which we are an
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453 # outgoing relay. It is assumed that such hosts are most likely to be MUAs,
454 # so we set control=submission to make Exim treat the message as a
455 # submission. It will fix up various errors in the message, for example, the
456 # lack of a Date: header line. If you are actually relaying out out from
457 # MTAs, you may want to disable this. If you are handling both relaying from
458 # MTAs and submissions from MUAs you should probably split them into two
459 # lists, and handle them differently.
460
461 # Recipient verification is omitted here, because in many cases the clients
462 # are dumb MUAs that don't cope well with SMTP error responses. If you are
463 # actually relaying out from MTAs, you should probably add recipient
464 # verification here.
465
466 # Note that, by putting this test before any DNS black list checks, you will
467 # always accept from these hosts, even if they end up on a black list. The
468 # assumption is that they are your friends, and if they get onto a black
469 # list, it is a mistake.
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470
471 accept hosts = +relay_from_hosts
cc38ddbf 472 control = submission
94f85d3e 473 control = dkim_disable_verify
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474
475 # Accept if the message arrived over an authenticated connection, from
476 # any host. Again, these messages are usually from MUAs, so recipient
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477 # verification is omitted, and submission mode is set. And again, we do this
478 # check before any black list tests.
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479
480 accept authenticated = *
cc38ddbf 481 control = submission
94f85d3e 482 control = dkim_disable_verify
5de37277 483
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484 # Insist that a HELO/EHLO was accepted.
485
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486 require message = nice hosts say HELO first
487 condition = ${if def:sender_helo_name}
731c6a90 488
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489 # Insist that any other recipient address that we accept is either in one of
490 # our local domains, or is in a domain for which we explicitly allow
491 # relaying. Any other domain is rejected as being unacceptable for relaying.
492
493 require message = relay not permitted
8bffe342 494 domains = +local_domains : +relay_to_domains
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495
496 # We also require all accepted addresses to be verifiable. This check will
497 # do local part verification for local domains, but only check the domain
498 # for remote domains. The only way to check local parts for the remote
499 # relay domains is to use a callout (add /callout), but please read the
500 # documentation about callouts before doing this.
501
502 require verify = recipient
503
059ec3d9 504 #############################################################################
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505 # There are no default checks on DNS black lists because the domains that
506 # contain these lists are changing all the time. However, here are two
507 # examples of how you can get Exim to perform a DNS black list lookup at this
508 # point. The first one denies, whereas the second just warns.
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509 #
510 # deny message = rejected because $sender_host_address is in a black list at $dnslist_domain\n$dnslist_text
511 # dnslists = black.list.example
512 #
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513 # warn dnslists = black.list.example
514 # add_header = X-Warning: $sender_host_address is in a black list at $dnslist_domain
059ec3d9 515 # log_message = found in $dnslist_domain
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516 #############################################################################
517
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518 #############################################################################
519 # This check is commented out because it is recognized that not every
520 # sysadmin will want to do it. If you enable it, the check performs
521 # Client SMTP Authorization (csa) checks on the sending host. These checks
522 # do DNS lookups for SRV records. The CSA proposal is currently (May 2005)
523 # an Internet draft. You can, of course, add additional conditions to this
524 # ACL statement to restrict the CSA checks to certain hosts only.
525 #
526 # require verify = csa
527 #############################################################################
528
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529 #############################################################################
530 # If doing per-user content filtering then recipients with filters different
531 # to the first recipient must be deferred unless the sender talks PRDR.
532 #
533 # defer !condition = $prdr_requested
534 # condition = ${if > {0}{$receipients_count}}
535 # condition = ${if !eq {$acl_m_content_filter} \
536 # {${lookup PER_RCPT_CONTENT_FILTER}}}
537 # warn !condition = $prdr_requested
538 # condition = ${if > {0}{$receipients_count}}
539 # set acl_m_content_filter = ${lookup PER_RCPT_CONTENT_FILTER}
540 #############################################################################
541
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542 # At this point, the address has passed all the checks that have been
543 # configured, so we accept it unconditionally.
059ec3d9 544
9ecb03f3 545 accept
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546
547
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548# This ACL is used once per recipient, for multi-recipient messages, if
549# we advertised PRDR. It can be used to perform receipient-dependent
550# header- and body- based filtering and rejections.
551# We set a variable to record that PRDR was active used, so that checking
552# in the data ACL can be skipped.
553
554.ifdef _HAVE_PRDR
555acl_check_prdr:
556 warn set acl_m_did_prdr = y
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557
558 #############################################################################
559 # do lookup on filtering, with $local_part@$domain, deny on filter match
560 #
561 # deny set acl_m_content_filter = ${lookup PER_RCPT_CONTENT_FILTER}
562 # condition = ...
563 #############################################################################
564
565 accept
23def169 566.endif
95dfacf2 567
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568# This ACL is used after the contents of a message have been received. This
569# is the ACL in which you can test a message's headers or body, and in
570# particular, this is where you can invoke external virus or spam scanners.
571# Some suggested ways of configuring these tests are shown below, commented
572# out. Without any tests, this ACL accepts all messages. If you want to use
573# such tests, you must ensure that Exim is compiled with the content-scanning
574# extension (WITH_CONTENT_SCAN=yes in Local/Makefile).
575
576acl_check_data:
577
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578 # Deny if the message contains an overlong line. Per the standards
579 # we should never receive one such via SMTP.
580 #
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581 deny message = maximum allowed line length is 998 octets, \
582 got $max_received_linelength
583 condition = ${if > {$max_received_linelength}{998}}
8c952127 584
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585 # Deny if the headers contain badly-formed addresses.
586 #
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587 deny !verify = header_syntax
588 message = header syntax
589 log_message = header syntax ($acl_verify_message)
4b7a7471 590
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591 # Deny if the message contains a virus. Before enabling this check, you
592 # must install a virus scanner and set the av_scanner option above.
593 #
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594 # deny malware = *
595 # message = This message contains a virus ($malware_name).
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596
597 # Add headers to a message if it is judged to be spam. Before enabling this,
598 # you must install SpamAssassin. You may also need to set the spamd_address
599 # option above.
600 #
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601 # warn spam = nobody
602 # add_header = X-Spam_score: $spam_score\n\
603 # X-Spam_score_int: $spam_score_int\n\
604 # X-Spam_bar: $spam_bar\n\
605 # X-Spam_report: $spam_report
74e0617f 606
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607 #############################################################################
608 # No more tests if PRDR was actively used.
609 # accept condition = ${if def:acl_m_did_prdr}
610 #
611 # To get here, all message recipients must have identical per-user
612 # content filtering (enforced by RCPT ACL). Do lookup for filter
613 # and deny on match.
614 #
615 # deny set acl_m_content_filter = ${lookup PER_RCPT_CONTENT_FILTER}
616 # condition = ...
617 #############################################################################
618
619
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620 # Accept the message.
621
622 accept
623
624
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625
626######################################################################
627# ROUTERS CONFIGURATION #
628# Specifies how addresses are handled #
629######################################################################
630# THE ORDER IN WHICH THE ROUTERS ARE DEFINED IS IMPORTANT! #
631# An address is passed to each router in turn until it is accepted. #
632######################################################################
633
634begin routers
635
636# This router routes to remote hosts over SMTP by explicit IP address,
637# when an email address is given in "domain literal" form, for example,
638# <user@[192.168.35.64]>. The RFCs require this facility. However, it is
639# little-known these days, and has been exploited by evil people seeking
640# to abuse SMTP relays. Consequently it is commented out in the default
641# configuration. If you uncomment this router, you also need to uncomment
642# allow_domain_literals above, so that Exim can recognize the syntax of
643# domain literal addresses.
644
645# domain_literal:
646# driver = ipliteral
647# domains = ! +local_domains
648# transport = remote_smtp
649
650
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651# This router can be used when you want to send all mail to a
652# server which handles DNS lookups for you; an ISP will typically run such
653# a server for their customers. The hostname in route_data comes from the
654# macro defined at the top of the file. If not defined, then we'll use the
655# dnslookup router below instead.
656# Beware that the hostname is specified again in the Transport.
657
658.ifdef ROUTER_SMARTHOST
659
660smarthost:
661 driver = manualroute
662 domains = ! +local_domains
663 transport = smarthost_smtp
664 route_data = ROUTER_SMARTHOST
665 ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1
666 no_more
667
668.else
669
059ec3d9 670# This router routes addresses that are not in local domains by doing a DNS
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671# lookup on the domain name. The exclamation mark that appears in "domains = !
672# +local_domains" is a negating operator, that is, it can be read as "not". The
673# recipient's domain must not be one of those defined by "domainlist
674# local_domains" above for this router to be used.
675#
676# If the router is used, any domain that resolves to 0.0.0.0 or to a loopback
677# interface address (127.0.0.0/8) is treated as if it had no DNS entry. Note
678# that 0.0.0.0 is the same as 0.0.0.0/32, which is commonly treated as the
679# local host inside the network stack. It is not 0.0.0.0/0, the default route.
680# If the DNS lookup fails, no further routers are tried because of the no_more
681# setting, and consequently the address is unrouteable.
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682
683dnslookup:
684 driver = dnslookup
685 domains = ! +local_domains
686 transport = remote_smtp
687 ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
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688# if ipv6-enabled then instead use:
689# ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1
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690 no_more
691
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692# This closes the ROUTER_SMARTHOST ifdef around the choice of routing for
693# off-site mail.
694.endif
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695
696
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697# The remaining routers handle addresses in the local domain(s), that is those
698# domains that are defined by "domainlist local_domains" above.
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699
700
701# This router handles aliasing using a linearly searched alias file with the
702# name SYSTEM_ALIASES_FILE. When this configuration is installed automatically,
703# the name gets inserted into this file from whatever is set in Exim's
704# build-time configuration. The default path is the traditional /etc/aliases.
705# If you install this configuration by hand, you need to specify the correct
706# path in the "data" setting below.
707#
708##### NB You must ensure that the alias file exists. It used to be the case
709##### NB that every Unix had that file, because it was the Sendmail default.
710##### NB These days, there are systems that don't have it. Your aliases
711##### NB file should at least contain an alias for "postmaster".
712#
713# If any of your aliases expand to pipes or files, you will need to set
714# up a user and a group for these deliveries to run under. You can do
715# this by uncommenting the "user" option below (changing the user name
716# as appropriate) and adding a "group" option if necessary. Alternatively, you
717# can specify "user" on the transports that are used. Note that the transports
718# listed below are the same as are used for .forward files; you might want
719# to set up different ones for pipe and file deliveries from aliases.
720
721system_aliases:
722 driver = redirect
723 allow_fail
724 allow_defer
725 data = ${lookup{$local_part}lsearch{SYSTEM_ALIASES_FILE}}
726# user = exim
727 file_transport = address_file
728 pipe_transport = address_pipe
729
730
731# This router handles forwarding using traditional .forward files in users'
732# home directories. If you want it also to allow mail filtering when a forward
733# file starts with the string "# Exim filter" or "# Sieve filter", uncomment
734# the "allow_filter" option.
735
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736# The no_verify setting means that this router is skipped when Exim is
737# verifying addresses. Similarly, no_expn means that this router is skipped if
738# Exim is processing an EXPN command.
739
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740# If you want this router to treat local parts with suffixes introduced by "-"
741# or "+" characters as if the suffixes did not exist, uncomment the two local_
742# part_suffix options. Then, for example, xxxx-foo@your.domain will be treated
743# in the same way as xxxx@your.domain by this router. Because this router is
744# not used for verification, if you choose to uncomment those options, then you
745# will *need* to make the same change to the localuser router. (There are
746# other approaches, if this is undesirable, but they add complexity).
747
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748# The check_ancestor option means that if the forward file generates an
749# address that is an ancestor of the current one, the current one gets
750# passed on instead. This covers the case where A is aliased to B and B
751# has a .forward file pointing to A.
752
753# The three transports specified at the end are those that are used when
754# forwarding generates a direct delivery to a file, or to a pipe, or sets
755# up an auto-reply, respectively.
756
757userforward:
758 driver = redirect
759 check_local_user
760# local_part_suffix = +* : -*
761# local_part_suffix_optional
762 file = $home/.forward
763# allow_filter
764 no_verify
765 no_expn
766 check_ancestor
767 file_transport = address_file
768 pipe_transport = address_pipe
769 reply_transport = address_reply
770
771
772# This router matches local user mailboxes. If the router fails, the error
773# message is "Unknown user".
774
775# If you want this router to treat local parts with suffixes introduced by "-"
776# or "+" characters as if the suffixes did not exist, uncomment the two local_
777# part_suffix options. Then, for example, xxxx-foo@your.domain will be treated
778# in the same way as xxxx@your.domain by this router.
779
780localuser:
781 driver = accept
782 check_local_user
783# local_part_suffix = +* : -*
784# local_part_suffix_optional
785 transport = local_delivery
786 cannot_route_message = Unknown user
787
788
789
790######################################################################
791# TRANSPORTS CONFIGURATION #
792######################################################################
793# ORDER DOES NOT MATTER #
794# Only one appropriate transport is called for each delivery. #
795######################################################################
796
797# A transport is used only when referenced from a router that successfully
798# handles an address.
799
800begin transports
801
802
803# This transport is used for delivering messages over SMTP connections.
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804# Refuse to send any message with over-long lines, which could have
805# been received other than via SMTP. The use of message_size_limit to
8c952127 806# enforce this is a red herring.
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807
808remote_smtp:
809 driver = smtp
8c952127 810 message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
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811.ifdef _HAVE_PRDR
812 hosts_try_prdr = *
813.endif
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814
815
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816# This transport is used for delivering messages to a smarthost, if the
817# smarthost router is enabled. This starts from the same basis as
818# "remote_smtp" but then turns on various security options, because
819# we assume that if you're told "use smarthost.example.org as the smarthost"
820# then there will be TLS available, with a verifiable certificate for that
821# hostname, using decent TLS.
822
823smarthost_smtp:
824 driver = smtp
825 message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}}
826 multi_domain
827 #
828.ifdef _HAVE_TLS
829 # Comment out any of these which you have to, then file a Support
830 # request with your smarthost provider to get things fixed:
831 hosts_require_tls = *
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832 tls_verify_hosts = *
833 # As long as tls_verify_hosts is enabled, this won't matter, but if you
834 # have to comment it out then this will at least log whether you succeed
835 # or not:
836 tls_try_verify_hosts = *
837 #
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838 # The SNI name should match the name which we'll expect to verify;
839 # many mail systems don't use SNI and this doesn't matter, but if it does,
840 # we need to send a name which the remote site will recognize.
aa6e77af 841 # This _should_ be the name which the smarthost operators specified as
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842 # the hostname for sending your mail to.
843 tls_sni = ROUTER_SMARTHOST
844 #
26739076 845.ifdef _HAVE_OPENSSL
bdf9ce82 846 tls_require_ciphers = HIGH:!aNULL:@STRENGTH
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847.endif
848.ifdef _HAVE_GNUTLS
bdf9ce82 849 tls_require_ciphers = SECURE192:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1
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850.endif
851.endif
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852.ifdef _HAVE_PRDR
853 hosts_try_prdr = *
854.endif
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855
856
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857# This transport is used for local delivery to user mailboxes in traditional
858# BSD mailbox format. By default it will be run under the uid and gid of the
859# local user, and requires the sticky bit to be set on the /var/mail directory.
860# Some systems use the alternative approach of running mail deliveries under a
861# particular group instead of using the sticky bit. The commented options below
862# show how this can be done.
863
864local_delivery:
865 driver = appendfile
cf8b2c57 866 file = /var/mail/$home
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867 delivery_date_add
868 envelope_to_add
869 return_path_add
870# group = mail
871# mode = 0660
872
873
874# This transport is used for handling pipe deliveries generated by alias or
875# .forward files. If the pipe generates any standard output, it is returned
876# to the sender of the message as a delivery error. Set return_fail_output
877# instead of return_output if you want this to happen only when the pipe fails
878# to complete normally. You can set different transports for aliases and
879# forwards if you want to - see the references to address_pipe in the routers
880# section above.
881
882address_pipe:
883 driver = pipe
884 return_output
885
886
887# This transport is used for handling deliveries directly to files that are
888# generated by aliasing or forwarding.
889
890address_file:
891 driver = appendfile
892 delivery_date_add
893 envelope_to_add
894 return_path_add
895
896
897# This transport is used for handling autoreplies generated by the filtering
898# option of the userforward router.
899
900address_reply:
901 driver = autoreply
902
903
904
905######################################################################
906# RETRY CONFIGURATION #
907######################################################################
908
909begin retry
910
911# This single retry rule applies to all domains and all errors. It specifies
912# retries every 15 minutes for 2 hours, then increasing retry intervals,
913# starting at 1 hour and increasing each time by a factor of 1.5, up to 16
914# hours, then retries every 6 hours until 4 days have passed since the first
915# failed delivery.
916
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917# WARNING: If you do not have any retry rules at all (this section of the
918# configuration is non-existent or empty), Exim will not do any retries of
919# messages that fail to get delivered at the first attempt. The effect will
920# be to treat temporary errors as permanent. Therefore, DO NOT remove this
921# retry rule unless you really don't want any retries.
922
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923# Address or Domain Error Retries
924# ----------------- ----- -------
925
926* * F,2h,15m; G,16h,1h,1.5; F,4d,6h
927
928
929
930######################################################################
931# REWRITE CONFIGURATION #
932######################################################################
933
934# There are no rewriting specifications in this default configuration file.
935
936begin rewrite
937
938
939
940######################################################################
941# AUTHENTICATION CONFIGURATION #
942######################################################################
943
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944# The following authenticators support plaintext username/password
945# authentication using the standard PLAIN mechanism and the traditional
946# but non-standard LOGIN mechanism, with Exim acting as the server.
947# PLAIN and LOGIN are enough to support most MUA software.
948#
949# These authenticators are not complete: you need to change the
950# server_condition settings to specify how passwords are verified.
951# They are set up to offer authentication to the client only if the
952# connection is encrypted with TLS, so you also need to add support
953# for TLS. See the global configuration options section at the start
954# of this file for more about TLS.
955#
956# The default RCPT ACL checks for successful authentication, and will accept
957# messages from authenticated users from anywhere on the Internet.
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958
959begin authenticators
960
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961# PLAIN authentication has no server prompts. The client sends its
962# credentials in one lump, containing an authorization ID (which we do not
963# use), an authentication ID, and a password. The latter two appear as
964# $auth2 and $auth3 in the configuration and should be checked against a
965# valid username and password. In a real configuration you would typically
966# use $auth2 as a lookup key, and compare $auth3 against the result of the
967# lookup, perhaps using the crypteq{}{} condition.
968
969#PLAIN:
970# driver = plaintext
971# server_set_id = $auth2
972# server_prompts = :
973# server_condition = Authentication is not yet configured
d9b2312b 974# server_advertise_condition = ${if def:tls_in_cipher }
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975
976# LOGIN authentication has traditional prompts and responses. There is no
977# authorization ID in this mechanism, so unlike PLAIN the username and
978# password are $auth1 and $auth2. Apart from that you can use the same
979# server_condition setting for both authenticators.
980
981#LOGIN:
982# driver = plaintext
983# server_set_id = $auth1
984# server_prompts = <| Username: | Password:
985# server_condition = Authentication is not yet configured
d9b2312b 986# server_advertise_condition = ${if def:tls_in_cipher }
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987
988
989######################################################################
990# CONFIGURATION FOR local_scan() #
991######################################################################
992
993# If you have built Exim to include a local_scan() function that contains
994# tables for private options, you can define those options here. Remember to
995# uncomment the "begin" line. It is commented by default because it provokes
996# an error with Exim binaries that are not built with LOCAL_SCAN_HAS_OPTIONS
997# set in the Local/Makefile.
998
999# begin local_scan
1000
1001
1002# End of Exim configuration file