[Mailman-Users] infinite loop on bounce from postmaster to list

[Rich Ramos]

We had an ugly situation occur yesterday.

Here's the summary:
1.  1+ Meg email sent to list with no size limit
2.  An email user, who has a ccMail account that forwards his mail on to 
another account outside the company, has his outside mailbox hit his quota 
limit.  (This user is also digested)
3.  The MTA at the receiving end that detects the over quota and sends an 
email back to the list itself (see below for mail headers as to why this 
might happen).
4.  Mailman sends this email back to everyone on the list including the 
digested mail user, whose MTA then rejects the email for the same reason as 
before.
5.  Repeat steps 3 and 4 about every 8 minutes.

This loop continues until the system comes to a halt from a full /tmp 
directory.  On every iteration the mail message grew a little bigger 
because the last email gets copied on to the reject message.

There are a few problems here, but I'm not sure which problem is the wrong 
case and which solution I should pursue.


Problem #1.  ccMail changes the headers when it processes the mail.

Here's the normal headers from a post to mailman (I've stripped the 
Received lines):
From: Rich Ramos <rich at chi.mti.com>
To: test at chi.mti.com
Message-ID: <563517.996585740@[144.86.11.157]>
X-Mailer: Mulberry/2.1.0b3 (Mac OS X)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Subject: [Test] test to show headers
Sender: test-admin at chi.mti.com
Errors-To: test-admin at chi.mti.com
X-BeenThere: test at chi.mti.com
X-Mailman-Version: 2.0.3
Precedence: bulk
List-Help: <mailto:test-request at chi.mti.com?subject=help>
List-Post: <mailto:test at chi.mti.com>
List-Subscribe: <http://chi.mti.com/mailman/listinfo/test>,
	<mailto:test-request at chi.mti.com?subject=subscribe>
List-Id: <test.chi.mti.com>
List-Unsubscribe: <http://chi.mti.com/mailman/listinfo/test>,
	<mailto:test-request at chi.mti.com?subject=unsubscribe>
List-Archive: <http://chi.mti.com/mailman/private/test/>
Date: Tue, 31 Jul 2001 13:22:20 -0500

Here's the way the headers get changed by ccmail:
Message-Id: <0107319966.AA996603967 at ccmgate.mti.com>
X-Mailer: ccMail Link to SMTP R8.30.00.7
Date: Tue, 31 Jul 2001 13:22:20 -0700
From: Rich Ramos <rich at chi.mti.com>
To: <test at chi.mti.com>
Subject: [Test] test to show headers
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="simple boundary"

As you can tell it's quite a bit different.  However I'm not totally clear 
that even with the changed headers, that the destination MTA should have 
sent the bounce message back to the list.  With the From: and To: headers 
the way they are why didn't the MTA send the bouce back to the From: 
address?

Problem #2:
The message was being delivered to a digested user, however the bounces 
happened every few minutes.  Why didn't the digest get sent once and then 
not again until the next interval for the digest?

Doesn't mailman have some mechanism to catch looping posts to a list?

-Rich