X-Git-Url: https://vcs.fsf.org/?p=exim.git;a=blobdiff_plain;f=src%2Fsrc%2Fconfigure.default;h=d757c0b393ab8dff275fa2d3b6899acc892f6202;hp=0ccbbe85587dab805208322b1cdc0e5437f227e6;hb=refs%2Ftags%2Fexim-4.92-RC3;hpb=d9b2312be1c63d0bf94dfaea9c82c6def6b45884 diff --git a/src/src/configure.default b/src/src/configure.default index 0ccbbe855..d757c0b39 100644 --- a/src/src/configure.default +++ b/src/src/configure.default @@ -37,9 +37,22 @@ +###################################################################### +# 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 @@ -56,7 +69,9 @@ domainlist local_domains = @ domainlist relay_to_domains = -hostlist relay_from_hosts = 127.0.0.1 +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, @@ -91,12 +106,13 @@ hostlist relay_from_hosts = 127.0.0.1 # 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 +# 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. +# 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 @@ -149,6 +165,9 @@ acl_smtp_data = acl_check_data # tls_certificate = /etc/ssl/exim.crt # tls_privatekey = /etc/ssl/exim.pem +# For OpenSSL, prefer EC- over RSA-authenticated ciphers +# tls_require_ciphers = ECDSA:RSA:!COMPLEMENTOFDEFAULT + # 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. @@ -218,18 +237,33 @@ never_users = root 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.) +# 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 -rfc1413_hosts = * -rfc1413_query_timeout = 5s + +# 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. +# +prdr_enable = true # By default, Exim expects all envelope addresses to be fully qualified, that @@ -245,6 +279,13 @@ rfc1413_query_timeout = 5s # 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 @@ -311,6 +352,18 @@ timeout_frozen_after = 7d # 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 # @@ -418,6 +471,11 @@ acl_check_rcpt: control = submission control = dkim_disable_verify + # Insist that a HELO/EHLO was accepted. + + require message = nice hosts say HELO first + condition = ${if def:sender_helo_name} + # 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. @@ -474,6 +532,19 @@ acl_check_rcpt: acl_check_data: + # Deny if the message contains an overlong line. Per the standards + # we should never receive one such via SMTP. + # + deny message = maximum allowed line length is 998 octets, \ + got $max_received_linelength + condition = ${if > {$max_received_linelength}{998}} + + # 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. # @@ -521,6 +592,25 @@ begin routers # 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 @@ -539,8 +629,15 @@ 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 + dnssec_request_domains = * 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. @@ -649,9 +746,55 @@ begin transports # This transport is used for delivering messages over SMTP connections. +# Refuse to send any message with over-long lines, which could have +# been received other than via SMTP. The use of message_size_limit to +# enforce this is a red herring. remote_smtp: driver = smtp + message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}} +.ifdef _HAVE_DANE + dnssec_request_domains = * + hosts_try_dane = * +.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 + message_size_limit = ${if > {$max_received_linelength}{998} {1}{0}} + 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 won't matter, 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 you 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 +.endif # This transport is used for local delivery to user mailboxes in traditional