The local channel is used to deliver messages to addresses on the local host. On OpenVMS, the local channel is the l (lowercase L) channel. On OpenVMS systems, this channel interfaces to the standard VMS MAIL utility. The local channel is also used on OpenVMS to interface PMDF to PSIMail. The conversion of PSIMail addresses to RFC 822 addresses is described in the following sections.

On OpenVMS systems, DECnet MAIL-11 channels, d and d_, are used to deliver messages via VMS MAIL to remote hosts using the MAIL-11 protocol. These channels differ from the local channel only in that, for messages queued to the channels, the host name in envelope To: addresses is significant. The local channel program is also used to service DECnet MAIL-11 channels.

MAIL_ channels are used on OpenVMS systems to provide specialized interfaces to other foreign mail transports that attach to VMS MAIL.

Many of the details of the operation of the local channel are described in Chapter 19 and in the PMDF User's Guide, OpenVMS Edition. In particular, the PMDF User's Guide, OpenVMS Edition describes those aspects of PMDF that are visible through the VMS MAIL user interface.

The automatic configuration generator always generates a local channel and, if needed, a d channel.