1 = Mail Transfer Agents = 2 3 Although this documentation does not seek to cover the details of configuring 4 mail transfer agent (MTA) software, some hints and tips are offered to help 5 avoid frustration. 6 7 <<TableOfContents(2,3)>> 8 9 == General == 10 11 Some general measures are presented below. 12 13 === Hostname === 14 15 The `hostname` command should provide a suitable hostname on the system, or MTAs 16 may behave strangely. This can be tested with the following command: 17 18 {{{ 19 hostname -f 20 }}} 21 22 It should report a fully-qualified hostname. 23 24 === Mailname === 25 26 The contents of `/etc/mailname` should probably be the fully-qualified hostname, 27 at least for Exim and Postfix. See 28 [[https://wiki.debian.org/EtcMailName|the Debian Wiki page]] for more details. 29 30 === Interfaces === 31 32 Some software attempts to listen on interfaces that may not be supported. For 33 example, Exim may be configured to listen on both IPv4 and IPv6 interfaces, even 34 in environments (such as User Mode Linux) where IPv6 interfaces may not be 35 available. 36 37 === Authentication === 38 39 It is highly undesirable to allow anyone to connect to a mail server to send 40 mail. However, it is highly convenient to allow imip-agent to connect to the 41 mail server on the same host without having to provide credentials. Consequently, 42 the configuration of an MTA must permit the latter without allowing the former. 43 44 Fortunately, many MTAs are configured to allow local connections because programs 45 typically rely on such traditional behaviour, but this may be worth checking if 46 mail server logs indicate authentication failures when imip-agent is attempting 47 to send mail. 48 49 == Exim == 50 51 On Debian, the following command can be run to adjust the configuration: 52 53 {{{ 54 dpkg-reconfigure exim4-config 55 }}} 56 57 The following questions are especially interesting: 58 59 {{{{#!table 60 '''Question''' || '''Remarks''' 61 == 62 IP-addresses to listen on for incoming SMTP connections 63 || Remove IPv6 interfaces in User Mode Linux or other environments without 64 .. IPv6 support or Exim will not bother listening on IPv4 interfaces either. 65 == 66 System mail name 67 || State the fully-qualified hostname, not just the domain name, which is 68 .. what the dialogue suggests is sufficient. For example: 69 {{{ 70 mailserver.example.com 71 }}} 72 == 73 Other destinations for which mail is accepted 74 || This is a colon-separated list that should indicate the local domain as 75 .. well as the unqualified hostname. For example: 76 {{{ 77 mailserver:example.com 78 }}} 79 }}}}