[Mailman-Users] Bounce email going to list server admin not list owner...

[Stephen J. Turnbull]

The Mailing List System Admin writes:

 > Didn't have luck researching this question.  I (the list server admin)
 > recently received the following bounce notice:

 > > From Joe.Anybody at example.edu Wed Feb 24 15:55:18 2016
 > > Return-Path: <mailman-loop at lists.example.edu>
 > > From: "Anybody, Joe" <Joe.Anybody at example.edu>
 > > To: Xyz.Forum <mailman-bounces at lists.example.edu>
 > > Subject: Automatic reply: Added to the list
 > > Thread-Topic: Added to the list
 > > X-Auto-Response-Suppress: All
 > > X-MS-Exchange-Inbox-Rules-Loop: Joe.Anybody at example.edu
 > > auto-submitted: auto-generated
 > > x-ms-exchange-generated-message-source: Mailbox Rules Agent
 > > Errors-To: mailman-loop at lists.example.edu
 > > Sender: "Mailman" <mailman-loop at lists.example.edu>
 > > Subject: Automatic reply: Added to the list
 > >  > > I am out of the office...
 > 
 > I don't understand why this bounce went to the server admin list...
 >
 >      mailman-bounces: "|/usr/local/mailman/mail/mailman bounces mailman"

Because it was explicitly addressed to that mailbox.

 > and not the bounce address for the specific list involved...
 > 
 >      xyz.forum-bounces: |"/usr/local/mailman/mail/mailman bounces xyz.forum"
 >

This isn't a bounce.  A bounce is an *undeliverable* message returned
to sender, and indicates that the user's mailbox is temporarily or
permanently invalid.

The message was delivered, and there is no need for bounce processing.
This mailbox is clearly not invalid.  The user is just ignoring it,
and telling people not to expect intelligent responses for a while.

 > I did a dump of the "Xyz.Forum" list's config for what appear
 > to be the relevant parameters:

They're not, because this isn't a bounce.

 > It is apparent from the "To:" that the name of the list involved was
 > known.

I'm not sure why this user's "vacation" message was addressed to
"mailman-bounces".  Probably because subscription notifications are
handled at the server, rather than the list, level.  It does appear
from such messages I have in my archives that messages from the
software are "From" the site rather than "From" the list.

I doubt the format of "you were subscribed" messages is going to
change for Mailman 2 (but Mark is authoritative on that).  It might be
a reasonable feature request for Mailman 3.  However, it would have to
be examined carefully for the possibility of creating mail loops or
other forms of misaddressing.

 > I don't mind getting bounces where a specific list is unknown, but
 > list specific bounces really need to go to the list owner.

At bottom, this one is a "people" problem.  Somebody subscribed Joe
Anybody to a list while he was on "out of office".  That's a no-no in
any case -- this mailbox is now going to be spamming the list with
"out of the office" messages.  Vacation agents don't work and play
nicely with mailing lists.  Somebody ought to tune yours to not
respond to list traffic, or disable it altogether.

There are three header fields that could be used for this purpose:
X-Mailman-Version, X-List-Administrivia, and List-ID.  I think
X-Mailman-Version is present in all Mailman traffic (hardcoded).
X-List-Administrivia won't appear in posts, and List-ID *should* be
present but it is a configuration option.

Also, this kind of event could in fact indicate a site-wide problem,
in the case of a "joe job" where the victim is signed up for numerous
mailing lists to annoy them (and perhaps execute a DoS attack if
there's a limit on the size of the mailbox).