The mail server channel provides a group of automated server facilities that respond to commands sent as electronic mail messages. The basic idea is very simple. A user sends a mail message to the server requesting some type of service. The server responds by sending one or more response messages. The server can also update various local databases as part of the processing of some commands (e.g., mailing lists).
The mail server channel program presently provides three general types of services: distribution of general information about itself, file serving, and mailing list manipulation.
Distribution of general information means that the mail server will
send general information about the server, in the form of mail
messages, in response to requests for information. These requests are
currently limited to the commands
INFO (a synonym for
File serving means that the mail server will process commands
requesting files and will mail the requested files back to the
SEND command is used to request files and
DIRECTORY command can be used to find out what files
are actually available. The
commands are used to specify how the file or files are read and encoded
prior to being sent.
Mailing list manipulation means that the mail server will accept
requests for subscription to or removal from various mailing lists that
have been placed under the control of the mail server. The
UNSUBSCRIBE commands perform
the basic mailing list functions. The
command can be used to find out what lists are available, and the
SEND/LIST command can be used to obtain a list of the
current subscribers to a given list.5
It is important to keep in mind that
handles files; in particular,
MAILSERV can manage mailing
list membership files. But
MAILSERV has nothing to do with
mailing list postings; postings to the list are handled by PMDF proper
MAILSERV merely manages
subscriptions to and from the list and queries for a copy of the list.
For a complete discussion on PMDF mailing lists, see Section 4.1.
5 By default, the