9.2 Using mailfromd with MeTA1.

MeTA1 (http://www.meta1.org) is an MTA of next generation which is designed to provide the following main features:

• Security
• Reliability
• Efficiency
• Configurability
• Extendibility

Instead of using Sendmail-compatible Milter protocol, it implements a new protocol, called policy milter, therefore an additional program is required to communicate with mailfromd. This program is a Pmilter–Milter multiplexer pmult, which is part of the ‘Mailfromd’ distribution. See pmult, for a detailed description of its configuration.

The configuration of ‘Meta1--Mailfromf’ interaction can be subdivided into three tasks.

1. Configure mailfromd

   This was already covered in previous chapters. No special ‘MeTA1’-dependent configuration is needed.

2. Configure pmult to communicate with mailfromd

   This is described in detail in pmult.

3. Set up MeTA1 to communicate with pmult

   The MeTA1 configuration file is located in /etc/meta1/meta1.conf. Configure the smtps component, by adding the following section:

   policy_milter {
       socket {
           type = type;
           address = addr;
           [path = path;]
           [port = port-no;]
       };
       [timeout = interval;]
       [flags = { flag };]
   };
   

   Statements in square brackets are optional. The meaning of each instruction is as follows:

   type = type

   Set the type of the socket to communicate with pmult. Allowed values for type are:

   inet

   Use INET socket. The socket address and port number are set using the address and port statements (see below).

   unix

   Use UNIX socket. The socket path is given by the path statement (see below).

   Notice, that depending on the type setting you have to set up either address/port or path, but not both.

   address = addr

   Configure the socket address for type = inet. Addr is the IP address on which pmult is listening (see listen statement).

   port = port-no

   Port number pmult is listening on (see listen statement).

   path = socket-file

   Full pathname of the socket file, if type = unix.

   timeout = interval

   Sets the maximum amount of time to wait for a reply from pmult.

   The behavior of smtps in case of time out depends on the flags settings:

   flags = { flag }

   Flag is one of the following:

   abort

   If pmult does not respond, abort the current SMTP session with a ‘421’ error.

   accept_but_reconnect

   If pmult does not respond, continue the current session but try to reconnect for the next session.

For example, if the pmult configuration has:

listen inet://127.0.0.1:3333;

then the corresponding part in /etc/meta1/meta1.conf will be

smtps {
    policy_milter {
        socket {
            type = inet;
            address = 127.0.0.1;
            port = 3333;
        };
        …
    };
    …
};

Similarly, if the pmult configuration has:

listen unix:///var/spool/meta1/pmult/socket;

then the /etc/meta1/meta1.conf should have:

smtps {
    policy_milter {
        socket {
            type = unix;
            path = /var/spool/meta1/pmult/socket;
        };
        …
    };
    …
};