Message files queued to the l channel are delivered to local users by the local channel program l_master.

When l_master runs, it checks to see whether the recipient of the message has a .forward file in their home directory and, if so, re-enqueues the message to all recipient entries specified in that file.

For a user who does not have .forward file or who has a .forward specifying "normal" delivery, PMDF will next check if there is an entry applying to that user in the PMDF user profile database and if there is, deliver accordingly. The user profile database delivery specification, if there is one, is executed just as if it were an entry in the user's .forward file.

For users who need "privileged" forwarding, see also pipe channels, as documented in Section 27.5.

If no forwarding has been established for the user via one of the above mechanisms, then the l channel simply delivers to the user's directory under /var/mail. (In particular, note that a default entry in the PMDF profile database can be a convenient way to specify that by default deliveries should be made to an alternate location.)