The local channel is used to deliver messages to addresses on the local host. On UNIX, the local channel is the l (lowercase L) channel.

When using a mail user agent on the local system to send mail (to anywhere), /pmdf/bin/sendmail is invoked as the replacement for sendmail to queue the messages to the appropriate queues, and then the channel programs for those queues will process the messages. Such local mail user agents can include mail, mailx, mailtool, Pine, etc.---any mail user agent that normally invokes sendmail.

The pmdf configuration utility always generates a local channel.