Uncaught bounce from Dovecot when Quota Exceeded

VERP must be enabled in Mailman. Putting

VERP_DELIVERY_INTERVAL = 1

in mm_cfg.py will enable Mailman's VERP for all messages.

If you attach a copy of the raw bounce message from Dovecot to this report, I will try to update the heuristic recognizers to recognize it. You can obfuscate any personal information such as email addresses or domain names.

Note that if Dovecot sends an RFC 1894/RFC 3464 compliant DSN, it should be recognized.

Attach raw message....

I added "VERP_DELIVERY_INTERVAL = 1" to mm_cfg.py.... when I try it I will post the results.

Thanks for you quick response.

The underlying issue is that the bounce from the Dovecot LDA is not an RFC 3464 Delivery Status Notification, but rather is an RFC 3798 Message Disposition Notification and Mailman doesn't currently recognize these.

I have worked around this for the moment by adding the "Your message to <email address hidden> was automatically rejected:" line to the simple text matcher, but the proper fix is to add recognition for RFC 3798 Message Disposition Notifications to Mailman.

I have thought about this some more and looked more carefully at RFC 3798, and I don't think RFC 3798 MDNs should be considered bounces. The first paragraph of the Abstract of RFC 3798 says:

   This memo defines a MIME content-type that may be used by a mail user
   agent (MUA) or electronic mail gateway to report the disposition of a
   message after it has been successfully delivered to a recipient.
   This content-type is intended to be machine-processable. Additional
   message headers are also defined to permit Message Disposition
   Notifications (MDNs) to be requested by the sender of a message. The
   purpose is to extend Internet Mail to support functionality often
   found in other messaging systems, such as X.400 and the proprietary
   "LAN-based" systems, and often referred to as "read receipts,"
   "acknowledgements", or "receipt notifications." The intention is to
   do this while respecting privacy concerns, which have often been
   expressed when such functions have been discussed in the past.

The key point is that the purpose of an MDN is for an MUA to report the disposition of a message after it has been successfully delivered to a recipient. Thus, it's use by the Dovecot LDA to report non-delivery due to over quota or other reasons seems incorrect, and Dovecot should be sending a DSN with a 'failed' action for the recipient rather than an MDN with a 'deleted' disposition which is intended to report that the message was deleted by the recipient after successful delivery and which should not in general be interpreted as a bounce.

Thus, I think Dovecot's behavior is incorrect, and the best we can do in Mailman is to recognize the "Your message to <email address hidden> was automatically rejected:" line in the simple text matcher as a work around.

Then is a Dovecot bug, the problem is that the version in Debian Lenny is 1.0.15 and the lastest stable is 2.0.8 (1.2.16 in the 1.x brach) so is hard to know if it's already fixed in the lastest versions.

I tested the "VERP_DELIVERY_INTERVAL = 1".... It works, but I don't like the results since it sends one message per recipient and the Postfix queque gets saturated and the whole system is slow down and I'm not able to throttle or assign a lower priority to Mailman.

I'm going to check out the simple text matcher as work around.

The patch to Mailman/Bouncers/SimpleMatch.py is at <http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/revision/1269?start_revid=1269>.

I reported this issue to the Dovecot mailing list at <http://dovecot.org/pipermail/dovecot/2010-December/055920.html>, but no response so far.

Note that it is possible to do the VERPing in Postfix rather than in Mailman. See the patch at <https://bugs.launchpad.net/mailman/+bug/558067>.