You may not be able to find the necessary clues from the LISTSERV log
file alone, you might also need the SMTP service log from your list host
site (or the host site admin to review it for you).  To describe in a
bit more detail what has been suggested to you, the problem is like
this:  a subscriber on your list has a misconfigured or badly-written
mail service.  When a message from your list reaches that system, their
service sends it back in such a way as to make it appear to LISTSERV as
a duplicate post, so the ORIGINAL poster gets a dup-reject notice, not
the person with the bad mail system. What you need to find is the
identity of the bad-setup mail service.  In the SMTP log for your list
host site, look for an INcoming mail *after* the INcoming mail of the
original poster, corresponding to the time of the dup-reject notice.
There may also be useful clues in the header data of the copy included
with the reject notice.  You might want to post to the list yourself,
just to get your own reject notice with your message (and hopefully the
useful header data) to review.

You mention a subscriber forward setup, and say it would explain only
one - not so.  The subscriber with the bad forwarding setup would be
receiving every message sent out by the list, and would badly-forward
each one, generating a dupe problem each time.


>>> [log in to unmask] 4/12/2006 6:10:26 PM >>>
I understand what you are saying, but this problem occurs when *any*
subscriber posts to the list, not just one. From what my subscribers
are
reporting, this happens with every post to the list. I first checked to
be
sure the list was not subscribed to itself. I also considered a
subscriber
might have a forward setup that was sending list posts back to the
list
address. But that would only explain one such incident, like your
misconfigured header idea, and not how this happens with every post,
from
every subscriber.

The log entries I previously copied to this list were made by
different
subscribers. I have a copy of the logs from that entire day, and with
every
post, the duplicate error message was sent out. So, what the
subscribers are
reporting is, in fact, occuring.

Any ideas?

----- Original Message ----- 
From: "F. J. Kelley" <[log in to unmask]>

look at the "Received:" headers.  One of your subscribers
mailers is misconfigured and is reposting to the list.
you will need to look these headers over very carefully
(start at the bottom), but the key is when you see your
listserver address(es) the second time (ie the mail leaves
the listserver then shows up back at the listserver as if it
were a new post).