Each LISTSERV article is uniquely generated by a message-ID, either the
one in the original (sender's) header or one generated by the first
LISTSERV (I mean peer) to process the message. However, this message-ID
is a "hidden" tag so you need SET listname FULLHDR to see it.
Now of course if the NETNEWS gateway were to post the same item to
LISTSERV several times, it would be distributed several times, too. The
gateway must see to it that duplicates are eliminated.
Eric