[Mailman-Users] Eliminating Duplicate Postings

Barry Finkel b19141 at britaine.ctd.anl.gov
Thu Dec 6 19:58:20 CET 2007

I wrote, in part:

>>I have not been in contact with the recipient to determine exactly what
>>he/she did.  I would like to prevent this from occurring in the future.

and Mark Sapiro replied:

It's hard to know what happened, but I wouldn't be surprised if it were
not some brain dead MTA doing this. I have seen messages returned to me
that apparently got to some MTA that then decided to deliver a copy
back to me apparently because I was in a To: or Cc: header of the

Go to the archives/private/listname.mbox/listname.mbox file and find
the second message (or a copy of it if you have it) and look at the
chain of Received:  headers for clues.

All I can tell is that the original mail went to some address

     _________ at lsu.edu

at 7AM, and at 17:02 a mailer at LSU sent the mail back to Mailman.
The only way I am going to be able to tell what happened is to contact
the recipient at LSU and ask him what he might have done.

I did see two copies of the mail in the mbox file, as you suggested
I would.

>I am confused about the Postfix log entry. The X-BeenThere: header is
>generated by Mailman on outgoing mail and is checked by Mailman on
>incoming mail to avoid reposting the same message to the same list. A
>message to a list with an X-BeenThere: for that list will be discarded
>and logged as a discard in the vette log.
>Postfix should pay no attention to an X-BeenThere: header, but It may
>have detected a loop on some other criteria.

I do not know why the copy to the second Mailman list here was blocked
by Postfix.  If I have some spare time, I will research the Postfix
syslog message.
Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory          Phone:    +1 (630) 252-7277
9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
Building 222, Room D209              Internet: BSFinkel at anl.gov
Argonne, IL   60439-4828             IBMMAIL:  I1004994

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