list(ADM)                       19 June 1992                       list(ADM)


 Name

    list - list processor channel for MMDF

 Syntax

    list

 Description

    list is an MMDF channel program for handling mailing lists.  The channel
    functions as a feed-through between deliver and submit.  The list channel
    has its own host table and domain table with one entry for the pseudo
    host ``list-processor'' or something similar.  This program is called by
    the program deliver and is not meant to be invoked by users directly.

    The list channel performs two basic services.  First, it postpones the
    verification of the list addresses and performs the (possibly lengthy)
    verification in the background when the list channel resubmits the mes-
    sage to the mail system.  This prevents tying up a network connection or
    a user's terminal when verifying a long mailing list.  Second, the list
    channel will, under special circumstances, change the return address for
    the message to a generic maintainer's address.  The return address is
    determined by first taking the destination address (for example,
    ``largelist'') and seeing if there is an address in the alias file called
    ``largelist-request''.  If there is, then ``largelist-request'' is used
    as the return address.  If that was not found, the list channel checks to
    see if the destination address has a trailing ``-outbound''.  If so, this
    is stripped and a ``-request'' is added and the lookup in the alias file
    is made a second time.  If the ``-request'' address is found, then that
    address is used as the return address.  If no ``-request'' address is
    found, then the original return address is used (normally the address of
    the sender).

    To use the list channel to process a list, it is generally necessary to
    make three entries in the alias file(s).  Let us say that we wish to set
    up a list called ``largelist'' and we want this list to be processed by
    the list channel.  We would need the following entries in the alias file:

       largelist:              largelist-outbound@list-processor
       largelist-outbound:     :include: /usr/mmdf/lists/largelist-file
       largelist-request:      maintainer

    The first line causes mail sent to ``largelist'' to be sent through the
    list processor, readdressed to ``largelist-outbound''.  The second line
    is what actually references the mailing list file for ``largelist''.  The
    third line is optional, and is used to set up the (informal) standard
    maintenance address.  This -request address, if present, will also be
    used by the list channel as the return address for mail submitted to the
    list.

 See also

    deliver(ADM), submit(ADM)

 File

    mmdf-table-directory/aliases    to find list-request addresses

 Credit

    MMDF was developed at the University of Delaware and is used with permis-
    sion.