We had an ugly situation occur yesterday.

Here's the summary: limit. (This user is also digested)

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

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@chi.mti.com To: test@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@chi.mti.com Errors-To: test-admin@chi.mti.com X-BeenThere: test@chi.mti.com X-Mailman-Version: 2.0.3 Precedence: bulk List-Help: mailto:test-request@chi.mti.com?subject=help List-Post: mailto:test@chi.mti.com List-Subscribe: http://chi.mti.com/mailman/listinfo/test, mailto:test-request@chi.mti.com?subject=subscribe List-Id: List-Unsubscribe: http://chi.mti.com/mailman/listinfo/test, mailto:test-request@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@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@chi.mti.com To: test@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