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diff --git a/exim4.conf b/exim4.conf new file mode 100644 index 0000000..23da0b9 --- /dev/null +++ b/exim4.conf @@ -0,0 +1,1022 @@ +# SPDX-License-Identifier: GPL-2.0-or-later +# Copyright (c) 2004-2023 University of Cambridge + +###################################################################### +# Runtime configuration file for Exim # +###################################################################### + + +# This is a default configuration file which will operate correctly in +# uncomplicated installations. Please see the manual for a complete list +# of all the runtime configuration options that can be included in a +# configuration file. There are many more than are mentioned here. The +# manual is in the file doc/spec.txt in the Exim distribution as a plain +# ASCII file. Other formats (PostScript, Texinfo, HTML, PDF) are available +# from the Exim ftp sites. The manual is also online at the Exim website. + + +# This file is divided into several parts, all but the first of which are +# headed by a line starting with the word "begin". Only those parts that +# are required need to be present. Blank lines, and lines starting with # +# are ignored. + + +########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ########### +# # +# Whenever you change Exim's configuration file, you *must* remember to # +# HUP the Exim daemon, because it will not pick up the new configuration # +# until you do. However, any other Exim processes that are started, for # +# example, a process started by an MUA in order to send a message, will # +# see the new configuration as soon as it is in place. # +# # +# You do not need to HUP the daemon for changes in auxiliary files that # +# are referenced from this file. They are read every time they are used. # +# # +# It is usually a good idea to test a new configuration for syntactic # +# correctness before installing it (for example, by running the command # +# "exim -C /config/file.new -bV"). # +# # +########### IMPORTANT ########## IMPORTANT ########### IMPORTANT ########### + + + +###################################################################### +# MACROS # +###################################################################### +# + +# If you want to use a smarthost instead of sending directly to recipient +# domains, uncomment this macro definition and set a real hostname. +# An appropriately privileged user can then redirect email on the command-line +# in emergencies, via -D. +# +# ROUTER_SMARTHOST=MAIL.HOSTNAME.FOR.CENTRAL.SERVER.EXAMPLE + +###################################################################### +# MAIN CONFIGURATION SETTINGS # +###################################################################### +# + +# Specify your host's canonical name here. This should normally be the fully +# qualified "official" name of your host. If this option is not set, the +# uname() function is called to obtain the name. In many cases this does +# the right thing and you need not set anything explicitly. + +# primary_hostname = + + +# The next three settings create two lists of domains and one list of hosts. +# These lists are referred to later in this configuration using the syntax +# +local_domains, +relay_to_domains, and +relay_from_hosts, respectively. They +# are all colon-separated lists: + +domainlist local_domains = @ +domainlist relay_to_domains = +hostlist relay_from_hosts = localhost +# (We rely upon hostname resolution working for localhost, because the default +# uncommented configuration needs to work in IPv4-only environments.) + +# Most straightforward access control requirements can be obtained by +# appropriate settings of the above options. In more complicated situations, +# you may need to modify the Access Control Lists (ACLs) which appear later in +# this file. + +# The first setting specifies your local domains, for example: +# +# domainlist local_domains = my.first.domain : my.second.domain +# +# You can use "@" to mean "the name of the local host", as in the default +# setting above. This is the name that is specified by primary_hostname, +# as specified above (or defaulted). If you do not want to do any local +# deliveries, remove the "@" from the setting above. If you want to accept mail +# addressed to your host's literal IP address, for example, mail addressed to +# "user@[192.168.23.44]", you can add "@[]" as an item in the local domains +# list. You also need to uncomment "allow_domain_literals" below. This is not +# recommended for today's Internet. + +# The second setting specifies domains for which your host is an incoming relay. +# If you are not doing any relaying, you should leave the list empty. However, +# if your host is an MX backup or gateway of some kind for some domains, you +# must set relay_to_domains to match those domains. For example: +# +# domainlist relay_to_domains = *.myco.com : my.friend.org +# +# This will allow any host to relay through your host to those domains. +# See the section of the manual entitled "Control of relaying" for more +# information. + +# The third setting specifies hosts that can use your host as an outgoing relay +# to any other host on the Internet. Such a setting commonly refers to a +# complete local network as well as the localhost. For example: +# +# hostlist relay_from_hosts = <; 127.0.0.1 ; ::1 ; 192.168.0.0/16 +# +# The "/16" is a bit mask (CIDR notation), not a number of hosts. Note that you +# have to include 127.0.0.1 if you want to allow processes on your host to send +# SMTP mail by using the loopback address. A number of MUAs use this method of +# sending mail. Often, connections are made to "localhost", which might be ::1 +# on IPv6-enabled hosts. Do not forget CIDR for your IPv6 networks. + +# All three of these lists may contain many different kinds of item, including +# wildcarded names, regular expressions, and file lookups. See the reference +# manual for details. The lists above are used in the access control lists for +# checking incoming messages. The names of these ACLs are defined here: + +acl_smtp_rcpt = acl_check_rcpt +.ifdef _HAVE_PRDR +acl_smtp_data_prdr = acl_check_prdr +.endif +acl_smtp_data = acl_check_data + +# You should not change those settings until you understand how ACLs work. + + +# If you are running a version of Exim that was compiled with the content- +# scanning extension, you can cause incoming messages to be automatically +# scanned for viruses. You have to modify the configuration in two places to +# set this up. The first of them is here, where you define the interface to +# your scanner. This example is typical for ClamAV; see the manual for details +# of what to set for other virus scanners. The second modification is in the +# acl_check_data access control list (see below). + +# av_scanner = clamd:/tmp/clamd + + +# For spam scanning, there is a similar option that defines the interface to +# SpamAssassin. You do not need to set this if you are using the default, which +# is shown in this commented example. As for virus scanning, you must also +# modify the acl_check_data access control list to enable spam scanning. + +# spamd_address = 127.0.0.1 783 + + +# If Exim is compiled with support for TLS, you may want to change the +# following option so that Exim disallows certain clients from makeing encrypted +# connections. The default is to allow all. +# In the authenticators section below, there are template configurations for +# plaintext username/password authentication. This kind of authentication is +# only safe when used within a TLS connection, so the authenticators will only +# work if TLS is allowed here. + +# This is equivalent to the default. + +# tls_advertise_hosts = * + +# Specify the location of the Exim server's TLS certificate and private key. +# The private key must not be encrypted (password protected). You can put +# the certificate and private key in the same file, in which case you only +# need the first setting, or in separate files, in which case you need both +# options. + +# tls_certificate = /etc/ssl/exim.crt +# tls_privatekey = /etc/ssl/exim.pem + +# For OpenSSL, prefer EC- over RSA-authenticated ciphers +.ifdef _HAVE_OPENSSL +tls_require_ciphers = ECDSA:RSA:!COMPLEMENTOFDEFAULT +.endif + +# Don't offer resumption to (most) MUAs, who we don't want to reuse +# tickets. Once the TLS extension for vended ticket numbers comes +# though, re-examine since resumption on a single-use ticket is still a benefit. +.ifdef _HAVE_TLS_RESUME +tls_resumption_hosts = ${if inlist {$received_port}{587:465} {:}{*}} +.endif + +# In order to support roaming users who wish to send email from anywhere, +# you may want to make Exim listen on other ports as well as port 25, in +# case these users need to send email from a network that blocks port 25. +# The standard ports for this purpose are: +# port 587, the "message submission" port - see RFC 4409 for details, +# and 465 the TLS-encrypted "submission" port, service name is "submissions", +# see RFC 8314. + +# Microsoft MUAs cannot be configured to +# talk the message submission protocol correctly, so if you need to support +# them you should also allow TLS-on-connect on the traditional (and now +# standard) port 465. + +# daemon_smtp_ports = 25 : 465 : 587 +# tls_on_connect_ports = 465 + + +# Specify the domain you want to be added to all unqualified addresses +# here. An unqualified address is one that does not contain an "@" character +# followed by a domain. For example, "caesar@rome.example" is a fully qualified +# address, but the string "caesar" (i.e. just a login name) is an unqualified +# email address. Unqualified addresses are accepted only from local callers by +# default. See the recipient_unqualified_hosts option if you want to permit +# unqualified addresses from remote sources. If this option is not set, the +# primary_hostname value is used for qualification. + +# qualify_domain = + + +# If you want unqualified recipient addresses to be qualified with a different +# domain to unqualified sender addresses, specify the recipient domain here. +# If this option is not set, the qualify_domain value is used. + +# qualify_recipient = + + +# The following line must be uncommented if you want Exim to recognize +# addresses of the form "user@[10.11.12.13]" that is, with a "domain literal" +# (an IP address) instead of a named domain. The RFCs still require this form, +# but it makes little sense to permit mail to be sent to specific hosts by +# their IP address in the modern Internet. This ancient format has been used +# by those seeking to abuse hosts by using them for unwanted relaying. If you +# really do want to support domain literals, uncomment the following line, and +# see also the "domain_literal" router below. + +# allow_domain_literals + + +# No deliveries will ever be run under the uids of users specified by +# never_users (a colon-separated list). An attempt to do so causes a panic +# error to be logged, and the delivery to be deferred. This is a paranoic +# safety catch. There is an even stronger safety catch in the form of the +# FIXED_NEVER_USERS setting in the configuration for building Exim. The list of +# users that it specifies is built into the binary, and cannot be changed. The +# option below just adds additional users to the list. The default for +# FIXED_NEVER_USERS is "root", but just to be absolutely sure, the default here +# is also "root". + +# Note that the default setting means you cannot deliver mail addressed to root +# as if it were a normal user. This isn't usually a problem, as most sites have +# an alias for root that redirects such mail to a human administrator. + +never_users = root + + +# The setting below causes Exim to do a reverse DNS lookup on all incoming +# IP calls, in order to get the true host name. If you feel this is too +# expensive, you can specify the networks for which a lookup is done, or +# remove the setting entirely. + +host_lookup = * + + +# The setting below causes Exim to try to initialize the system resolver +# library with DNSSEC support. It has no effect if your library lacks +# DNSSEC support. + +dns_dnssec_ok = 1 + + +# The settings below cause Exim to make RFC 1413 (ident) callbacks +# for all incoming SMTP calls. You can limit the hosts to which these +# calls are made, and/or change the timeout that is used. If you set +# the timeout to zero, all RFC 1413 calls are disabled. RFC 1413 calls +# are cheap and can provide useful information for tracing problem +# messages, but some hosts and firewalls have problems with them. +# This can result in a timeout instead of an immediate refused +# connection, leading to delays on starting up SMTP sessions. +# (The default was reduced from 30s to 5s for release 4.61. and to +# disabled for release 4.86) +# +#rfc1413_hosts = * +#rfc1413_query_timeout = 5s + + +# Enable an efficiency feature. We advertise the feature; clients +# may request to use it. For multi-recipient mails we then can +# reject or accept per-user after the message is received. +# This supports recipient-dependent content filtering; without it +# you have to temp-reject any recipients after the first that have +# incompatible filtering, and do the filtering in the data ACL. +# Even with this enabled, you must support the old style for peers +# not flagging support for PRDR (visible via $prdr_requested). +# +.ifdef _HAVE_PRDR +prdr_enable = true +.endif + + +# By default, Exim expects all envelope addresses to be fully qualified, that +# is, they must contain both a local part and a domain. If you want to accept +# unqualified addresses (just a local part) from certain hosts, you can specify +# these hosts by setting one or both of +# +# sender_unqualified_hosts = +# recipient_unqualified_hosts = +# +# to control sender and recipient addresses, respectively. When this is done, +# unqualified addresses are qualified using the settings of qualify_domain +# and/or qualify_recipient (see above). + + +# Unless you run a high-volume site you probably want more logging +# detail than the default. Adjust to suit. + +log_selector = +smtp_protocol_error +smtp_syntax_error \ + +tls_certificate_verified + + +# If you want Exim to support the "percent hack" for certain domains, +# uncomment the following line and provide a list of domains. The "percent +# hack" is the feature by which mail addressed to x%y@z (where z is one of +# the domains listed) is locally rerouted to x@y and sent on. If z is not one +# of the "percent hack" domains, x%y is treated as an ordinary local part. This +# hack is rarely needed nowadays; you should not enable it unless you are sure +# that you really need it. +# +# percent_hack_domains = +# +# As well as setting this option you will also need to remove the test +# for local parts containing % in the ACL definition below. + + +# When Exim can neither deliver a message nor return it to sender, it "freezes" +# the delivery error message (aka "bounce message"). There are also other +# circumstances in which messages get frozen. They will stay on the queue for +# ever unless one of the following options is set. + +# This option unfreezes frozen bounce messages after two days, tries +# once more to deliver them, and ignores any delivery failures. + +ignore_bounce_errors_after = 2d + +# This option cancels (removes) frozen messages that are older than a week. + +timeout_frozen_after = 7d + + +# By default, messages that are waiting on Exim's queue are all held in a +# single directory called "input" which is itself within Exim's spool +# directory. (The default spool directory is specified when Exim is built, and +# is often /var/spool/exim/.) Exim works best when its queue is kept short, but +# there are circumstances where this is not always possible. If you uncomment +# the setting below, messages on the queue are held in 62 subdirectories of +# "input" instead of all in the same directory. The subdirectories are called +# 0, 1, ... A, B, ... a, b, ... z. This has two benefits: (1) If your file +# system degrades with many files in one directory, this is less likely to +# happen; (2) Exim can process the queue one subdirectory at a time instead of +# all at once, which can give better performance with large queues. + +# split_spool_directory = true + + +# If you're in a part of the world where ASCII is not sufficient for most +# text, then you're probably familiar with RFC2047 message header extensions. +# By default, Exim adheres to the specification, including a limit of 76 +# characters to a line, with encoded words fitting within a line. +# If you wish to use decoded headers in message filters in such a way +# that successful decoding of malformed messages matters, you may wish to +# configure Exim to be more lenient. +# +# check_rfc2047_length = false +# +# In particular, the Exim maintainers have had multiple reports of problems +# from Russian administrators of issues until they disable this check, +# because of some popular, yet buggy, mail composition software. + + +# If you wish to be strictly RFC compliant, or if you know you'll be +# exchanging email with systems that are not 8-bit clean, then you may +# wish to disable advertising 8BITMIME. Uncomment this option to do so. + +# accept_8bitmime = false + + +# Exim does not make use of environment variables itself. However, +# libraries that Exim uses (e.g. LDAP) depend on specific environment settings. +# There are two lists: keep_environment for the variables we trust, and +# add_environment for variables we want to set to a specific value. +# Note that TZ is handled separately by the timezone runtime option +# and TIMEZONE_DEFAULT buildtime option. + +# keep_environment = ^LDAP +# add_environment = PATH=/usr/bin::/bin + + + +###################################################################### +# ACL CONFIGURATION # +# Specifies access control lists for incoming SMTP mail # +###################################################################### + +begin acl + +# This access control list is used for every RCPT command in an incoming +# SMTP message. The tests are run in order until the address is either +# accepted or denied. + +acl_check_rcpt: + + # Accept if the source is local SMTP (i.e. not over TCP/IP). We do this by + # testing for an empty sending host field. + + accept hosts = : + control = dkim_disable_verify + + ############################################################################# + # The following section of the ACL is concerned with local parts that contain + # @ or % or ! or / or | or dots in unusual places. + # + # The characters other than dots are rarely found in genuine local parts, but + # are often tried by people looking to circumvent relaying restrictions. + # Therefore, although they are valid in local parts, these rules lock them + # out, as a precaution. + # + # Empty components (two dots in a row) are not valid in RFC 2822, but Exim + # allows them because they have been encountered. (Consider local parts + # constructed as "firstinitial.secondinitial.familyname" when applied to + # someone like me, who has no second initial.) However, a local part starting + # with a dot or containing /../ can cause trouble if it is used as part of a + # file name (e.g. for a mailing list). This is also true for local parts that + # contain slashes. A pipe symbol can also be troublesome if the local part is + # incorporated unthinkingly into a shell command line. + # + # Two different rules are used. The first one is stricter, and is applied to + # messages that are addressed to one of the local domains handled by this + # host. The line "domains = +local_domains" restricts it to domains that are + # defined by the "domainlist local_domains" setting above. The rule blocks + # local parts that begin with a dot or contain @ % ! / or |. If you have + # local accounts that include these characters, you will have to modify this + # rule. + + deny message = Restricted characters in address + domains = +local_domains + local_parts = ^[.] : ^.*[@%!/|] + + # The second rule applies to all other domains, and is less strict. The line + # "domains = !+local_domains" restricts it to domains that are NOT defined by + # the "domainlist local_domains" setting above. The exclamation mark is a + # negating operator. This rule allows your own users to send outgoing + # messages to sites that use slashes and vertical bars in their local parts. + # It blocks local parts that begin with a dot, slash, or vertical bar, but + # allows these characters within the local part. However, the sequence /../ + # is barred. The use of @ % and ! is blocked, as before. The motivation here + # is to prevent your users (or your users' viruses) from mounting certain + # kinds of attack on remote sites. + + deny message = Restricted characters in address + domains = !+local_domains + local_parts = ^[./|] : ^.*[@%!] : ^.*/\\.\\./ + ############################################################################# + + # Accept mail to postmaster in any local domain, regardless of the source, + # and without verifying the sender. + + accept local_parts = postmaster + domains = +local_domains + + # Deny unless the sender address can be verified. + + require verify = sender + + # Reject all RCPT commands after too many bad recipients + # This is partly a defense against spam abuse and partly attacker abuse. + # Real senders should manage, by the time they get to 10 RCPT directives, + # to have had at least half of them be real addresses. + # + # This is a lightweight check and can protect you against repeated + # invocations of more heavy-weight checks which would come after it. + + deny condition = ${if and {\ + {>{$rcpt_count}{10}}\ + {<{$recipients_count}{${eval:$rcpt_count/2}}} }} + message = Rejected for too many bad recipients + logwrite = REJECT [$sender_host_address]: bad recipient count high [${eval:$rcpt_count-$recipients_count}] + + # Accept if the message comes from one of the hosts for which we are an + # outgoing relay. It is assumed that such hosts are most likely to be MUAs, + # so we set control=submission to make Exim treat the message as a + # submission. It will fix up various errors in the message, for example, the + # lack of a Date: header line. If you are actually relaying out out from + # MTAs, you may want to disable this. If you are handling both relaying from + # MTAs and submissions from MUAs you should probably split them into two + # lists, and handle them differently. + + # Recipient verification is omitted here, because in many cases the clients + # are dumb MUAs that don't cope well with SMTP error responses. If you are + # actually relaying out from MTAs, you should probably add recipient + # verification here. + + # Note that, by putting this test before any DNS black list checks, you will + # always accept from these hosts, even if they end up on a black list. The + # assumption is that they are your friends, and if they get onto a black + # list, it is a mistake. + + accept hosts = +relay_from_hosts + control = submission + control = dkim_disable_verify + + # Accept if the message arrived over an authenticated connection, from + # any host. Again, these messages are usually from MUAs, so recipient + # verification is omitted, and submission mode is set. And again, we do this + # check before any black list tests. + + accept authenticated = * + control = submission + control = dkim_disable_verify + + # Insist that any other recipient address that we accept is either in one of + # our local domains, or is in a domain for which we explicitly allow + # relaying. Any other domain is rejected as being unacceptable for relaying. + + require message = relay not permitted + domains = +local_domains : +relay_to_domains + + # We also require all accepted addresses to be verifiable. This check will + # do local part verification for local domains, but only check the domain + # for remote domains. The only way to check local parts for the remote + # relay domains is to use a callout (add /callout), but please read the + # documentation about callouts before doing this. + + require verify = recipient + + ############################################################################# + # There are no default checks on DNS black lists because the domains that + # contain these lists are changing all the time. However, here are two + # examples of how you can get Exim to perform a DNS black list lookup at this + # point. The first one denies, whereas the second just warns. + # + # deny dnslists = black.list.example + # message = rejected because $sender_host_address is in a black list at $dnslist_domain\n$dnslist_text + # + # warn dnslists = black.list.example + # add_header = X-Warning: $sender_host_address is in a black list at $dnslist_domain + # log_message = found in $dnslist_domain + ############################################################################# + + ############################################################################# + # This check is commented out because it is recognized that not every + # sysadmin will want to do it. If you enable it, the check performs + # Client SMTP Authorization (csa) checks on the sending host. These checks + # do DNS lookups for SRV records. The CSA proposal is currently (May 2005) + # an Internet draft. You can, of course, add additional conditions to this + # ACL statement to restrict the CSA checks to certain hosts only. + # + # require verify = csa + ############################################################################# + + ############################################################################# + # If doing per-user content filtering then recipients with filters different + # to the first recipient must be deferred unless the sender talks PRDR. + # + # defer !condition = $prdr_requested + # condition = ${if > {0}{$recipients_count}} + # condition = ${if !eq {$acl_m_content_filter} \ + # {${lookup PER_RCPT_CONTENT_FILTER}}} + # warn !condition = $prdr_requested + # condition = ${if > {0}{$recipients_count}} + # set acl_m_content_filter = ${lookup PER_RCPT_CONTENT_FILTER} + ############################################################################# + + # At this point, the address has passed all the checks that have been + # configured, so we accept it unconditionally. + + accept + + +# This ACL is used once per recipient, for multi-recipient messages, if +# we advertised PRDR. It can be used to perform receipient-dependent +# header- and body- based filtering and rejections. +# We set a variable to record that PRDR was active used, so that checking +# in the data ACL can be skipped. + +.ifdef _HAVE_PRDR +acl_check_prdr: + warn set acl_m_did_prdr = y + + ############################################################################# + # do lookup on filtering, with $local_part@$domain, deny on filter match + # + # deny set acl_m_content_filter = ${lookup PER_RCPT_CONTENT_FILTER} + # condition = ... + ############################################################################# + + accept +.endif + +# This ACL is used after the contents of a message have been received. This +# is the ACL in which you can test a message's headers or body, and in +# particular, this is where you can invoke external virus or spam scanners. +# Some suggested ways of configuring these tests are shown below, commented +# out. Without any tests, this ACL accepts all messages. If you want to use +# such tests, you must ensure that Exim is compiled with the content-scanning +# extension (WITH_CONTENT_SCAN=yes in Local/Makefile). + +acl_check_data: + + # Deny if the message contains an overlong line. Per the standards + # we should never receive one such via SMTP. + # + deny condition = ${if > {$max_received_linelength}{998}} + message = maximum allowed line length is 998 octets, \ + got $max_received_linelength + + # Deny if the headers contain badly-formed addresses. + # + deny !verify = header_syntax + message = header syntax + log_message = header syntax ($acl_verify_message) + + # Deny if the message contains a virus. Before enabling this check, you + # must install a virus scanner and set the av_scanner option above. + # + # deny malware = * + # message = This message contains a virus ($malware_name). + + # Add headers to a message if it is judged to be spam. Before enabling this, + # you must install SpamAssassin. You may also need to set the spamd_address + # option above. + # + # warn spam = nobody + # add_header = X-Spam_score: $spam_score\n\ + # X-Spam_score_int: $spam_score_int\n\ + # X-Spam_bar: $spam_bar\n\ + # X-Spam_report: $spam_report + + ############################################################################# + # No more tests if PRDR was actively used. + # accept condition = ${if def:acl_m_did_prdr} + # + # To get here, all message recipients must have identical per-user + # content filtering (enforced by RCPT ACL). Do lookup for filter + # and deny on match. + # + # deny set acl_m_content_filter = ${lookup PER_RCPT_CONTENT_FILTER} + # condition = ... + ############################################################################# + + + # Accept the message. + + accept + + + +###################################################################### +# ROUTERS CONFIGURATION # +# Specifies how addresses are handled # +###################################################################### +# THE ORDER IN WHICH THE ROUTERS ARE DEFINED IS IMPORTANT! # +# An address is passed to each router in turn until it is accepted. # +###################################################################### + +begin routers + +# This router routes to remote hosts over SMTP by explicit IP address, +# when an email address is given in "domain literal" form, for example, +# <user@[192.168.35.64]>. The RFCs require this facility. However, it is +# little-known these days, and has been exploited by evil people seeking +# to abuse SMTP relays. Consequently it is commented out in the default +# configuration. If you uncomment this router, you also need to uncomment +# allow_domain_literals above, so that Exim can recognize the syntax of +# domain literal addresses. + +# domain_literal: +# driver = ipliteral +# domains = ! +local_domains +# transport = remote_smtp + + +# This router can be used when you want to send all mail to a +# server which handles DNS lookups for you; an ISP will typically run such +# a server for their customers. The hostname in route_data comes from the +# macro defined at the top of the file. If not defined, then we'll use the +# dnslookup router below instead. +# Beware that the hostname is specified again in the Transport. + +.ifdef ROUTER_SMARTHOST + +smarthost: + driver = manualroute + domains = ! +local_domains + transport = smarthost_smtp + route_data = ROUTER_SMARTHOST + ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1 + no_more + +.else + +# This router routes addresses that are not in local domains by doing a DNS +# lookup on the domain name. The exclamation mark that appears in "domains = ! +# +local_domains" is a negating operator, that is, it can be read as "not". The +# recipient's domain must not be one of those defined by "domainlist +# local_domains" above for this router to be used. +# +# If the router is used, any domain that resolves to 0.0.0.0 or to a loopback +# interface address (127.0.0.0/8) is treated as if it had no DNS entry. Note +# that 0.0.0.0 is the same as 0.0.0.0/32, which is commonly treated as the +# local host inside the network stack. It is not 0.0.0.0/0, the default route. +# If the DNS lookup fails, no further routers are tried because of the no_more +# setting, and consequently the address is unrouteable. + +dnslookup: + driver = dnslookup + domains = ! +local_domains + transport = remote_smtp + ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8 +# if ipv6-enabled then instead use: +# ignore_target_hosts = <; 0.0.0.0 ; 127.0.0.0/8 ; ::1 + no_more + +# This closes the ROUTER_SMARTHOST ifdef around the choice of routing for +# off-site mail. +.endif + + +# The remaining routers handle addresses in the local domain(s), that is those +# domains that are defined by "domainlist local_domains" above. + + +# This router handles aliasing using a linearly searched alias file with the +# name SYSTEM_ALIASES_FILE. When this configuration is installed automatically, +# the name gets inserted into this file from whatever is set in Exim's +# build-time configuration. The default path is the traditional /etc/aliases. +# If you install this configuration by hand, you need to specify the correct +# path in the "data" setting below. +# +##### NB You must ensure that the alias file exists. It used to be the case +##### NB that every Unix had that file, because it was the Sendmail default. +##### NB These days, there are systems that don't have it. Your aliases +##### NB file should at least contain an alias for "postmaster". +# +# If any of your aliases expand to pipes or files, you will need to set +# up a user and a group for these deliveries to run under. You can do +# this by uncommenting the "user" option below (changing the user name +# as appropriate) and adding a "group" option if necessary. Alternatively, you +# can specify "user" on the transports that are used. Note that the transports +# listed below are the same as are used for .forward files; you might want +# to set up different ones for pipe and file deliveries from aliases. + +system_aliases: + driver = redirect + allow_fail + allow_defer + data = ${lookup{$local_part}lsearch{SYSTEM_ALIASES_FILE}} +# user = exim + file_transport = address_file + pipe_transport = address_pipe + + +# This router handles forwarding using traditional .forward files in users' +# home directories. If you want it also to allow mail filtering when a forward +# file starts with the string "# Exim filter" or "# Sieve filter", uncomment +# the "allow_filter" option. + +# The no_verify setting means that this router is skipped when Exim is +# verifying addresses. Similarly, no_expn means that this router is skipped if +# Exim is processing an EXPN command. + +# If you want this router to treat local parts with suffixes introduced by "-" +# or "+" characters as if the suffixes did not exist, uncomment the two local_ +# part_suffix options. Then, for example, xxxx-foo@your.domain will be treated +# in the same way as xxxx@your.domain by this router. Because this router is +# not used for verification, if you choose to uncomment those options, then you +# will *need* to make the same change to the localuser router. (There are +# other approaches, if this is undesirable, but they add complexity). + +# The check_ancestor option means that if the forward file generates an +# address that is an ancestor of the current one, the current one gets +# passed on instead. This covers the case where A is aliased to B and B +# has a .forward file pointing to A. + +# The three transports specified at the end are those that are used when +# forwarding generates a direct delivery to a file, or to a pipe, or sets +# up an auto-reply, respectively. + +userforward: + driver = redirect + check_local_user +# local_part_suffix = +* : -* +# local_part_suffix_optional + file = $home/.forward +# allow_filter + no_verify + no_expn + check_ancestor + file_transport = address_file + pipe_transport = address_pipe + reply_transport = address_reply + + +# This router matches local user mailboxes. If the router fails, the error +# message is "Unknown user". + +# If you want this router to treat local parts with suffixes introduced by "-" +# or "+" characters as if the suffixes did not exist, uncomment the two local_ +# part_suffix options. Then, for example, xxxx-foo@your.domain will be treated +# in the same way as xxxx@your.domain by this router. + +localuser: + driver = accept + check_local_user +# local_part_suffix = +* : -* +# local_part_suffix_optional + transport = local_delivery + cannot_route_message = Unknown user + + + +###################################################################### +# TRANSPORTS CONFIGURATION # +###################################################################### +# ORDER DOES NOT MATTER # +# Only one appropriate transport is called for each delivery. # +###################################################################### + +# A transport is used only when referenced from a router that successfully +# handles an address. + +begin transports + + +# This transport is used for delivering messages over SMTP connections. + +remote_smtp: + driver = smtp +.ifdef _HAVE_TLS_RESUME + tls_resumption_hosts = * +.endif + + +# This transport is used for delivering messages to a smarthost, if the +# smarthost router is enabled. This starts from the same basis as +# "remote_smtp" but then turns on various security options, because +# we assume that if you're told "use smarthost.example.org as the smarthost" +# then there will be TLS available, with a verifiable certificate for that +# hostname, using decent TLS. + +smarthost_smtp: + driver = smtp + multi_domain + # +.ifdef _HAVE_TLS + # Comment out any of these which you have to, then file a Support + # request with your smarthost provider to get things fixed: + hosts_require_tls = * + tls_verify_hosts = * + # As long as tls_verify_hosts is enabled, this this will have no effect, + # but if you have to comment it out then this will at least log whether + # you succeed or not: + tls_try_verify_hosts = * + # + # The SNI name should match the name which we'll expect to verify; + # many mail systems don't use SNI and this doesn't matter, but if it does, + # we need to send a name which the remote site will recognize. + # This _should_ be the name which the smarthost operators specified as + # the hostname for sending your mail to. + tls_sni = ROUTER_SMARTHOST + # +.ifdef _HAVE_OPENSSL + tls_require_ciphers = HIGH:!aNULL:@STRENGTH +.endif +.ifdef _HAVE_GNUTLS + tls_require_ciphers = SECURE192:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1 +.endif +.ifdef _HAVE_TLS_RESUME + tls_resumption_hosts = * +.endif +.endif + + +# This transport is used for local delivery to user mailboxes in traditional +# BSD mailbox format. By default it will be run under the uid and gid of the +# local user, and requires the sticky bit to be set on the /var/mail directory. +# Some systems use the alternative approach of running mail deliveries under a +# particular group instead of using the sticky bit. The commented options below +# show how this can be done. + +local_delivery: + driver = appendfile + file = /var/mail/$local_part_data + delivery_date_add + envelope_to_add + return_path_add +# group = mail +# mode = 0660 + + +# This transport is used for handling pipe deliveries generated by alias or +# .forward files. If the pipe generates any standard output, it is returned +# to the sender of the message as a delivery error. Set return_fail_output +# instead of return_output if you want this to happen only when the pipe fails +# to complete normally. You can set different transports for aliases and +# forwards if you want to - see the references to address_pipe in the routers +# section above. + +address_pipe: + driver = pipe + return_output + + +# This transport is used for handling deliveries directly to files that are +# generated by aliasing or forwarding. + +address_file: + driver = appendfile + delivery_date_add + envelope_to_add + return_path_add + + +# This transport is used for handling autoreplies generated by the filtering +# option of the userforward router. + +address_reply: + driver = autoreply + + + +###################################################################### +# RETRY CONFIGURATION # +###################################################################### + +begin retry + +# This single retry rule applies to all domains and all errors. It specifies +# retries every 15 minutes for 2 hours, then increasing retry intervals, +# starting at 1 hour and increasing each time by a factor of 1.5, up to 16 +# hours, then retries every 6 hours until 4 days have passed since the first +# failed delivery. + +# WARNING: If you do not have any retry rules at all (this section of the +# configuration is non-existent or empty), Exim will not do any retries of +# messages that fail to get delivered at the first attempt. The effect will +# be to treat temporary errors as permanent. Therefore, DO NOT remove this +# retry rule unless you really don't want any retries. + +# Address or Domain Error Retries +# ----------------- ----- ------- + +* * F,2h,15m; G,16h,1h,1.5; F,4d,6h + + + +###################################################################### +# REWRITE CONFIGURATION # +###################################################################### + +# There are no rewriting specifications in this default configuration file. + +begin rewrite + + + +###################################################################### +# AUTHENTICATION CONFIGURATION # +###################################################################### + +# The following authenticators support plaintext username/password +# authentication using the standard PLAIN mechanism and the traditional +# but non-standard LOGIN mechanism, with Exim acting as the server. +# PLAIN and LOGIN are enough to support most MUA software. +# +# These authenticators are not complete: you need to change the +# server_condition settings to specify how passwords are verified. +# They are set up to offer authentication to the client only if the +# connection is encrypted with TLS, so you also need to add support +# for TLS. See the global configuration options section at the start +# of this file for more about TLS. +# +# The default RCPT ACL checks for successful authentication, and will accept +# messages from authenticated users from anywhere on the Internet. + +begin authenticators + +# PLAIN authentication has no server prompts. The client sends its +# credentials in one lump, containing an authorization ID (which we do not +# use), an authentication ID, and a password. The latter two appear as +# $auth2 and $auth3 in the configuration and should be checked against a +# valid username and password. In a real configuration you would typically +# use $auth2 as a lookup key, and compare $auth3 against the result of the +# lookup, perhaps using the crypteq{}{} condition. + +#PLAIN: +# driver = plaintext +# server_set_id = $auth2 +# server_prompts = : +# server_condition = Authentication is not yet configured +# server_advertise_condition = ${if def:tls_in_cipher } + +# LOGIN authentication has traditional prompts and responses. There is no +# authorization ID in this mechanism, so unlike PLAIN the username and +# password are $auth1 and $auth2. Apart from that you can use the same +# server_condition setting for both authenticators. + +#LOGIN: +# driver = plaintext +# server_set_id = $auth1 +# server_prompts = <| Username: | Password: +# server_condition = Authentication is not yet configured +# server_advertise_condition = ${if def:tls_in_cipher } + + +###################################################################### +# CONFIGURATION FOR local_scan() # +###################################################################### + +# If you have built Exim to include a local_scan() function that contains +# tables for private options, you can define those options here. Remember to +# uncomment the "begin" line. It is commented by default because it provokes +# an error with Exim binaries that are not built with LOCAL_SCAN_HAS_OPTIONS +# set in the Local/Makefile. + +# begin local_scan + + +# End of Exim configuration file |