imip-agent

Annotated docs/wiki/MailIntegration--MTA

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2017-10-24 Paul Boddie file changeset files shortlog Remove superfluous result collection slicing and count method parameter.
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= Mail Transfer Agents =
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Although this documentation does not seek to cover the details of configuring
 
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mail transfer agent (MTA) software, some hints and tips are offered to help
 
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avoid frustration.
 
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<<TableOfContents(2,3)>>
 
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== General ==
 
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Some general measures are presented below.
 
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=== Hostname ===
 
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The `hostname` command should provide a suitable hostname on the system, or MTAs
 
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may behave strangely. This can be tested with the following command:
 
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{{{
 
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hostname -f
 
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}}}
 
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It should report a fully-qualified hostname.
 
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=== Mailname ===
 
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The contents of `/etc/mailname` should probably be the fully-qualified hostname,
 
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at least for Exim and Postfix. See
 
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[[https://wiki.debian.org/EtcMailName|the Debian Wiki page]] for more details.
 
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=== Interfaces ===
 
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Some software attempts to listen on interfaces that may not be supported. For
 
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example, Exim may be configured to listen on both IPv4 and IPv6 interfaces, even
 
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in environments (such as User Mode Linux) where IPv6 interfaces may not be
 
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available.
 
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=== Authentication ===
 
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It is highly undesirable to allow anyone to connect to a mail server to send
 
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mail. However, it is highly convenient to allow imip-agent to connect to the
 
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mail server on the same host without having to provide credentials. Consequently,
 
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the configuration of an MTA must permit the latter without allowing the former.
 
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Fortunately, many MTAs are configured to allow local connections because programs
 
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typically rely on such traditional behaviour, but this may be worth checking if
 
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mail server logs indicate authentication failures when imip-agent is attempting
 
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to send mail.
 
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== Exim ==
 
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On Debian, the following command can be run to adjust the configuration:
 
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{{{
 
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dpkg-reconfigure exim4-config
 
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}}}
 
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The following questions are especially interesting:
 
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{{{{#!table
 
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'''Question''' || '''Remarks'''
 
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==
 
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IP-addresses to listen on for incoming SMTP connections
 
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|| Remove IPv6 interfaces in User Mode Linux or other environments without
 
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.. IPv6 support or Exim will not bother listening on IPv4 interfaces either.
 
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==
 
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System mail name
 
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|| State the fully-qualified hostname, not just the domain name, which is
 
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.. what the dialogue suggests is sufficient. For example:
 
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{{{
 
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mailserver.example.com
 
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}}}
 
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==
 
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Other destinations for which mail is accepted
 
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|| This is a colon-separated list that should indicate the local domain as
 
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.. well as the unqualified hostname. For example:
 
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{{{
 
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mailserver:example.com
 
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}}}
 
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}}}}
 
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== Useful Commands ==
 
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The following commands prove useful when troubleshooting and appear to be
 
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available as shown within a Debian environment.
 
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{{{#!table
 
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'''Task''' || '''Exim''' || '''Postfix'''
 
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==
 
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Check the mail queue
 
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||<colspan="2"> `mailq`
 
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==
 
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Process the mail queue
 
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|| `sendmail -q` (or `exim -q` or `runq`)
 
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|| `sendmail -q` (or `postqueue`)
 
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==
 
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Flush the mail queue
 
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|| `exim -qff`
 
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|| `postqueue -f`
 
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==
 
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Deliver a specific message
 
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|| `exim -M <identifier>`
 
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|| `postqueue -i <identifier>`
 
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==
 
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Test delivery for an address
 
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||<colspan="2"> `sendmail -bt <address>` (see also `sendmail -v -bv <address>` and `sendmail -v -bvs <address>`)
 
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}}}
 
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See [[http://bradthemad.org/tech/notes/exim_cheatsheet.php|Exim Cheatsheet]] and [[http://www.postfix.org/DEBUG_README.html|Postfix Debugging Howto]] for more guidance.