[Mailman-Users] Duplicate Subscribe/Unsubscribe Notifications

Brad Knowles brad at shub-internet.org
Sat Jan 27 01:52:57 CET 2007

At 4:41 PM -0500 1/26/07, Alan McConnell wrote:

>>  Check your queue-ids.  That will tell you where the duplication is
>>  occurring.
>	What are "queue-ids"?  Are they something that a mailman admin
>	can see?  I have no access to any log files; they are available
>	only to the sys-admins of my ISP.

The queue-ids are typically shown in the contents of the various 
"Received:" headers on each message.  They would also show up in the 
system logs for the mail server.  These logs may only be accessible 
to your mail server administrator -- they are outside of Mailman, and 
unfortunately not even the internal Mailman logs are available via 
the web.

For example, on the message I am responding to, this is a sample of 
the "Received:" headers I found:

Received: from bag.python.org (bag [])
	by bag.python.org (Postfix) with ESMTP id 943801E4011
	for <mailman-users at python.org>; Fri, 26 Jan 2007 22:42:32 +0100 (CET)
Received: from bag (HELO bag.python.org) (
	by bag.python.org with SMTP; 26 Jan 2007 22:42:32 +0100
Received: from jefferson.patriot.net (jefferson.patriot.net [])
	by bag.python.org (Postfix) with ESMTP
	for <mailman-users at python.org>; Fri, 26 Jan 2007 22:42:31 +0100 (CET)
Received: from patriot.net (postfix at pool180-173.patriot.net [])
	by jefferson.patriot.net (8.13.4/8.13.4/Debian-3sarge3) with ESMTP
	id l0QLgPrM022931; Fri, 26 Jan 2007 16:42:29 -0500
Received: by patriot.net (Postfix, from userid 500)
	id 8ABEC47587; Fri, 26 Jan 2007 16:41:37 -0500 (EST)

In each case, where it says "id 8ABEC47587" or "with ESMTP id 
l0QLgPrM022931", or something like that, the ids it is referring to 
are called "queue ids".  If you are looking at the system log for the 
mail services on a given server, the only way you can typically tie 
in a given log entry to a given message is through the queue-ids. 
Looking in the system log file for postfix on this machine, the 
entries relevant to queue-id 943801E4011 are:

Jan 26 22:42:32 bag postfix/smtpd[27954]: 943801E4011: client=bag[]
Jan 26 22:42:32 bag postfix/cleanup[28483]: 943801E4011: 
message-id=<20070126214137.GD3294 at patriot.net>
Jan 26 22:42:32 bag postfix/qmgr[27081]: 943801E4011: 
from=<alan at patriot.net>, size=2239, nrcpt=1 (queue active)
Jan 26 22:42:32 bag postfix/local[28226]: 943801E4011: 
to=<mailman-users at bag.python.org>, 
orig_to=<mailman-users at python.org>, relay=local, delay=0, status=sent 
(delivered to command: /usr/local/mailman/mail/mailman post 
Jan 26 22:42:32 bag postfix/qmgr[27081]: 943801E4011: removed

You see the message-id here once, but all the other log entries 
relative to this particular event are logged with only the date and 
the queue-id, as well as whatever other information was being logged. 
So, you need the queue-id in order to be able to tie them all 

Now, these are not the only log entries for this message.  Because of 
the way the mail server on this machine is configured, it actually 
handles each message three times -- once on inbound (before scanning 
for spam and viruses), once on inbound (after scanning), and again 
after the message has gone through Mailman and is being sent out.

So, if we look for other log entries relative to this message-id, we 
find that we have to look at 992 different queue-ids, one for each of 
the subscribers on the outbound side, plus one on inbound (before 
scanning) and another on inbound (after scanning).  I'll spare you 
and not even show you the complete list of all the queue-ids in 
question, and of course I'd never show you the complete set of all 
those log entries.

Anyway, my point is this -- if you look at the headers of two 
messages that appear to be identical, you can look at the "Received:" 
headers to see if they really are identical.  If each and every 
queue-id in both messages are exactly the same, then there must have 
been some sort of duplication that occurred within your mail client 
or somewhere else outside of the normal SMTP Message Transfer Agent 
system.  If the queue-ids are identical up to a point but they 
diverge after that point, that tells you exactly where the message 
was somehow duplicated.

Brad Knowles <brad at shub-internet.org>, Consultant & Author
Co-author of SAGE Booklet #15 "Internet Postmaster: Duties and 
Founding Member and Platinum Individual Sponsor of LOPSA: 
Papers: <http://tinyurl.com/tj6q4> LinkedIn Profile: 

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