[Mailman-Users] Looping problem...

Barry A. Warsaw barry at zope.com
Thu Aug 2 00:57:38 CEST 2001

>>>>> "TS" == TJ Snider <timsn at home.com> writes:

    TS> I just ended up with a nasty loop... just when starting up a
    TS> list.

    TS> Use Mailman 2.0.5.  Turn on the anonymous_list option, so mail
    TS> seems to come from the list.  Have someone on the list have a
    TS> vacation notice setup.

    TS> The notice loops... in this case up to 600 times, overnight,
    TS> before I caught it.

    TS> Is there any way of maintaining the anonymous_list feature
    TS> without the looping?  I've turned the anonymous_list feature
    TS> off, but if it can't handle vacation notices, what's the use?

I'm not sure what can be done on Mailman's end, but I think you have a
buggy vacation program on your hands.

I just checked the latest version of vacation on SourceForge, and it
seems to do many sane things to stop the loop on its end.  These
include: never respond to messages with "Precedence: bulk", and never
respond if the user is not in the To: or Cc: line.  Both of these
conditions should be true (thus suppressing vacation notices) for all
messages sent through Mailman.  So "working" vacation programs should
not generate mail loops.

How can Mailman defend against busted vacation programs?  /Maybe/ it
could look for "Subject: away from my mail".  Maybe it could look for
"User-Agent: vacation .*" as at least vacation 1.2.5 adds.  The former
seems quite error prone since the user can set that Subject: header to
anything they want.  Plus, you could set bounce_matching_headers to
trigger on this, holding such messages for approval.  The latter seems
useless because I'm guessing that any vacation program sophisticated
enough to add a User-Agent: header is also sophisticated enough to not
send the reply to a mailing list posting in the first place.


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