| paul@984 | 1 | = Mail Transfer Agents = |
| paul@984 | 2 | |
| paul@984 | 3 | Although this documentation does not seek to cover the details of configuring |
| paul@984 | 4 | mail transfer agent (MTA) software, some hints and tips are offered to help |
| paul@984 | 5 | avoid frustration. |
| paul@984 | 6 | |
| paul@988 | 7 | <<TableOfContents(2,3)>> |
| paul@988 | 8 | |
| paul@984 | 9 | == General == |
| paul@984 | 10 | |
| paul@984 | 11 | Some general measures are presented below. |
| paul@984 | 12 | |
| paul@984 | 13 | === Hostname === |
| paul@984 | 14 | |
| paul@984 | 15 | The `hostname` command should provide a suitable hostname on the system, or MTAs |
| paul@984 | 16 | may behave strangely. This can be tested with the following command: |
| paul@984 | 17 | |
| paul@984 | 18 | {{{ |
| paul@984 | 19 | hostname -f |
| paul@984 | 20 | }}} |
| paul@984 | 21 | |
| paul@984 | 22 | It should report a fully-qualified hostname. |
| paul@984 | 23 | |
| paul@988 | 24 | === Mailname === |
| paul@988 | 25 | |
| paul@988 | 26 | The contents of `/etc/mailname` should probably be the fully-qualified hostname, |
| paul@988 | 27 | at least for Exim and Postfix. See |
| paul@988 | 28 | [[https://wiki.debian.org/EtcMailName|the Debian Wiki page]] for more details. |
| paul@988 | 29 | |
| paul@984 | 30 | === Interfaces === |
| paul@984 | 31 | |
| paul@988 | 32 | Some software attempts to listen on interfaces that may not be supported. For |
| paul@988 | 33 | example, Exim may be configured to listen on both IPv4 and IPv6 interfaces, even |
| paul@988 | 34 | in environments (such as User Mode Linux) where IPv6 interfaces may not be |
| paul@988 | 35 | available. |
| paul@988 | 36 | |
| paul@988 | 37 | === Authentication === |
| paul@988 | 38 | |
| paul@988 | 39 | It is highly undesirable to allow anyone to connect to a mail server to send |
| paul@988 | 40 | mail. However, it is highly convenient to allow imip-agent to connect to the |
| paul@988 | 41 | mail server on the same host without having to provide credentials. Consequently, |
| paul@988 | 42 | the configuration of an MTA must permit the latter without allowing the former. |
| paul@988 | 43 | |
| paul@988 | 44 | Fortunately, many MTAs are configured to allow local connections because programs |
| paul@988 | 45 | typically rely on such traditional behaviour, but this may be worth checking if |
| paul@988 | 46 | mail server logs indicate authentication failures when imip-agent is attempting |
| paul@988 | 47 | to send mail. |
| paul@984 | 48 | |
| paul@984 | 49 | == Exim == |
| paul@984 | 50 | |
| paul@984 | 51 | On Debian, the following command can be run to adjust the configuration: |
| paul@984 | 52 | |
| paul@984 | 53 | {{{ |
| paul@984 | 54 | dpkg-reconfigure exim4-config |
| paul@984 | 55 | }}} |
| paul@984 | 56 | |
| paul@984 | 57 | The following questions are especially interesting: |
| paul@984 | 58 | |
| paul@984 | 59 | {{{{#!table |
| paul@984 | 60 | '''Question''' || '''Remarks''' |
| paul@984 | 61 | == |
| paul@984 | 62 | IP-addresses to listen on for incoming SMTP connections |
| paul@984 | 63 | || Remove IPv6 interfaces in User Mode Linux or other environments without |
| paul@984 | 64 | .. IPv6 support or Exim will not bother listening on IPv4 interfaces either. |
| paul@984 | 65 | == |
| paul@984 | 66 | System mail name |
| paul@984 | 67 | || State the fully-qualified hostname, not just the domain name, which is |
| paul@984 | 68 | .. what the dialogue suggests is sufficient. For example: |
| paul@984 | 69 | {{{ |
| paul@984 | 70 | mailserver.example.com |
| paul@984 | 71 | }}} |
| paul@984 | 72 | == |
| paul@984 | 73 | Other destinations for which mail is accepted |
| paul@984 | 74 | || This is a colon-separated list that should indicate the local domain as |
| paul@984 | 75 | .. well as the unqualified hostname. For example: |
| paul@984 | 76 | {{{ |
| paul@984 | 77 | mailserver:example.com |
| paul@984 | 78 | }}} |
| paul@984 | 79 | }}}} |
