[Mailman-Users] Mail/News duplicates problem

Brad Knowles brad at shub-internet.org
Thu May 1 19:48:53 CEST 2008

NFN Smith wrote:

> Where I'm having problems is with messages posted from the news side
> -- they're gated into Mailman, and distributed correctly to mailing
> list subscribers, but then a copy of the message goes back through to
> the INN server, and INN isn't recognizing the message as having been
> seen, and the result is that the news side of thing sees a duplicate
> copy of the message.

What I've seen a lot is that people tend to post to news with clients that 
also send out a copy by e-mail, and the mailing list is configured to 
gateway articles back to the newsgroup, thus resulting in duplicates.

Another source of duplication is if you have multiple people operating 
mail-to-news gateways.

> On further inspection, the duplicate message has clearly been
> submitted to news by Mailman, and includes lots of Mailman-specific
> headers.  In particular, the Message-ID: header is rewritten by
> Mailman, and I'm assuming that INN relies on Message-ID: to track what
> has been seen or not.

INN does rely on the Message-ID to track whether or not it has seen this 
particular message, but an article being gatewayed in via USENET should not 
then be gatewayed back out to USENET by Mailman.  The pipeline of routines 
within Mailman should be set up to avoid precisely that condition.

However, see FAQ 4.59 at 
<http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq04.059.htp> for 
the reasons why Mailman modifies the Message-ID header on incoming USENET news.

Brad Knowles <brad at shub-internet.org>
LinkedIn Profile: <http://tinyurl.com/y8kpxu>

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