Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!spool.mu.edu!uunet!wendy-fate.uu.net
From: kyle@wendy-fate.uu.net (Kyle Jones)
Newsgroups: news.software.b
Subject: Re: Sys file question
Message-ID: <120876@uunet.UU.NET>
Date: 2 Feb 91 04:26:18 GMT
References: <1991Feb1.112306.3072@daimi.aau.dk>
Sender: kyle@uunet.UU.NET
Lines: 23

datpete@daimi.aau.dk (Peter Andersen) writes:
 > [...] I try to gateway a mailing list into a local 
 > newsgroup (comp.special.group).
 >
 > When mails come from the mailing list, a small script posts these as
 > articles to comp.special.group with distribution 'local'.  When a local
 > user posts an article to comp.special.group with distribution 'local', I
 > want the article to go into the local database, and nowhere else.  When
 > a local user posts an article to comp.special.group with a distribution
 > wider than 'local', I mail it into the mailing list. In this case I
 > don't want the article to go into the local database, since it will
 > later appear in the mailing list, and then be gatewayed into the
 > newsgroup by the script mentioned above.  The reason for the sys-file
 > question is thus that I want to prevent that locally posted articles
 > appear twice in the newsgroup.

If a locally posted article is sent to the mailing list and loops back
with the same message ID, the news system will reject it as a
duplicate.  As long as that's the case, you can let articles with any
distribution be spooled by the news system, since it will keep track
of the message ID and reject the mailing list copy when it returns.
Just make sure the gateway to the mailing list doesn't give messages a
new message ID.