# $Cambridge: exim/src/src/configure.default,v 1.9 2006/07/07 13:54:32 ph10 Exp $ ###################################################################### # 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 web sites. # 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 ########### ###################################################################### # 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 = 127.0.0.1 # 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 List (ACL) which appears 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 : 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. # 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 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 enable the # following options so that Exim allows clients to make encrypted # connections. 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 the following TLS settings are turned on # as well. # Allow any client to use TLS. # 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 # 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 port for this purpose is port 587, the "message submission" # port. See RFC 4409 for details. 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 but # non-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 these 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 settings below, which are actually the same as the defaults in the # code, 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.) rfc1413_hosts = * rfc1413_query_timeout = 5s # 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). # 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 ###################################################################### # 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 = : ############################################################################# # 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 # 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 # 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 ############################################################################# # 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 message = rejected because $sender_host_address is in a black list at $dnslist_domain\n$dnslist_text # dnslists = black.list.example # # 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 ############################################################################# # Accept if the address is in a local domain, but only if the recipient can # be verified. Otherwise deny. The "endpass" line is the border between # passing on to the next ACL statement (if tests above it fail) or denying # access (if tests below it fail). accept domains = +local_domains endpass verify = recipient # Accept if the address is in a domain for which we are an incoming relay, # but again, only if the recipient can be verified. accept domains = +relay_to_domains endpass verify = recipient # Reaching the end of the ACL causes a "deny", but we might as well give # an explicit message. deny message = relay not permitted # 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 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 # 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, # . 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 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 no_more # 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. # 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. You probably want to make # the same change to the localuser router. # 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. # 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 = $home/.forward # allow_filter no_verify no_expn check_ancestor file_transport = address_file pipe_transport = address_pipe reply_transport = address_reply # This router matches local user mailboxes. If the router fails, the error # message is "Unknown user". # If you want this router to treat local parts with suffixes introduced by "-" # or "+" characters as if the suffixes did not exist, uncomment the two local_ # part_suffix options. Then, for example, xxxx-foo@your.domain will be treated # in the same way as xxxx@your.domain by this router. localuser: driver = accept check_local_user # local_part_suffix = +* : -* # local_part_suffix_optional transport = local_delivery cannot_route_message = Unknown user ###################################################################### # TRANSPORTS CONFIGURATION # ###################################################################### # ORDER DOES NOT MATTER # # Only one appropriate transport is called for each delivery. # ###################################################################### # A transport is used only when referenced from a router that successfully # handles an address. begin transports # This transport is used for delivering messages over SMTP connections. remote_smtp: driver = smtp # This transport is used for local delivery to user mailboxes in traditional # BSD mailbox format. By default it will be run under the uid and gid of the # local user, and requires the sticky bit to be set on the /var/mail directory. # Some systems use the alternative approach of running mail deliveries under a # particular group instead of using the sticky bit. The commented options below # show how this can be done. local_delivery: driver = appendfile file = /var/mail/$local_part 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. # 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_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_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