Mail Transports and Invoking Agent Programs

The essential aspect of mail system configuration involves mail transports and the integration of agent programs into the mail processing pipeline. A number of example files are provided here.

Such files need adjusting for the deployment environment so that, for example, the domain would be replaced with a suitable value.

If LMTP is being used, instances of LMTP_SOCKET in the example configuration files will need to be replaced with a suitable filesystem path. Where the lmtp system group is employed, it may be replaced with a different group. See the LMTP guide for a discussion of LMTP and mail delivery.

Transports in Exim

Example configuration files for Exim are distributed in conf/exim:




Integration of agent programs



These files can be incorporated into the Exim configuration. On Debian systems, they can be copied into /etc/exim4/conf.d/transport.

If local SMTP delivery is being used, the 30_exim4-config_people file (in conf/exim) will need adjusting.

Transports in Postfix

Example configuration files for Postfix are distributed in conf/postfix:



Integration of agent programs (for inclusion in


Configuration of agent transports


Configuration of outgoing mail routing

These files can be incorporated into the Postfix configuration. On Debian systems, can be merged into /etc/postfix/, whereas the remaining files would be installed into /etc/postfix.

If local SMTP delivery is being used, the file (in conf/postfix) will need adjusting.