######################################################################
# 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
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 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
+
-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
# 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
# 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 #
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.
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 message contains a virus. Before enabling this check, you
# must install a virus scanner and set the av_scanner option above.
#
# 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}}
# This transport is used for local delivery to user mailboxes in traditional