[Mailman-Users] endless reposting problem

Stephen J. Turnbull stephen at xemacs.org
Fri Sep 16 11:26:42 CEST 2005

>>>>> "Gil" == Gil Hardwick <ghar4399 at bigpond.net.au> writes:

    Gil> Some of my clients had their office auto-responder switch on,

This ought to be a firing offense ....  It's very simple.  There is a
standard for mailing lists, there are a bunch of headers (List-Id,
etc) that are required of conforming lists, and Mailman (by default)
conforms.  So all vacation programs need to do is not respond to
anything containing a List-Id header (or any other header indicating
bulk mail---I'm willing to bet that some of your users have just added
themselves to the "Golden Live Ones" list at Spammers International).

Unfortunately I can't recommend one; I have a canned stanza for
procmail for this, so have never investigated those programs.

Since there is no standard for vacation programs AFAIK, it is not
possible for mailman to reliably detect the vacation program.

    Gil> I thought only a member of the list could post to the list,
    Gil> in this case all moderated so I would have to approve all
    Gil> posts anyway.

The member vs moderation filters interact in a complicated,
nonintuitive way (or they did in 2.0, I'm not using them in 2.1).  You
should check these settings very carefully, as posts are obviously
getting through.

    Gil> If the list is not a member of itself, how can it keep
    Gil> posting the same mail to and from itself in a continuous
    Gil> loop?

It doesn't.  It sends mail to the user, whose vacation program sends a
canned _new_ message back, so Mailman can't identify it as the "moral
equivalent" of a bounce.  Mailman redistributes the vacation message,
the user gets it, which triggers the vacation reflex, and away we go.
Of course all the vacation messages look alike (because the vacation
program is too simple to come up with a new one every time), but if
you check carefully, you should see that each one has a unique
Message-ID, and possibly (if it's a really smart program) an
"In-Reply-To" header to a unique trigger post.

    Gil> Is there something else I need to configure to stop this happening?

You could chain the users to their workstations.<wink>  But you'll
probably have a better response if you find a decent vacation program.

School of Systems and Information Engineering http://turnbull.sk.tsukuba.ac.jp
University of Tsukuba                    Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
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