On Wed, 14 Jul 1993 14:52:43 PDT Tim Rushing <RUSHING@WSUVM1> wrote:
>Here's the sequence of events:
>1.  A subscriber posts to the list.
 1A. LISTSERV calculates a "checksum" for the posting and saves the value.
>2.  Subscriber receives confirmation from listserv that
>    posting has been processed and sent.
>3.  Posting is sent to the list.  People *do* receive it.
 3A. Some subscriber grabs the message, and posts it back to 'TESL-L@CUNYVM',
     either maliciously, or, with the help of some "I'm on vacation" software.
 3B. LISTSERV calculates the checksum for this posting,
     and finds that it matches the checksum from a recent posting.
 3C. LISTSERV decides to **not** distribute the "duplicate" posting
     to the subscribers.
>4.  Original poster receives message from LISTSERV, saying
>    the posting has been rejected because it is a duplicate posting.
 5.  List-owner breathes a sigh of relief,
     because LISTSERV's "loop-detection" code has prevented a loop
     which would have bombarded each subscriber with hundreds of copies
     of the same message. :-)
 
>The message saying the posting is rejected shows it has gone through a mailer
>at ccmail.wiu.bgu.edu.  We have been in touch with the acting postmaster to no
>avail.  (The regular postmaster is on vacation.)
>Any guesses on the problem?  We have set all users at that site
>to NOMAIL and the problem has gone away,
>but since it is not the fault of those users,
>I'd like suggestions for a solution.
 
It *MUST* be the fault of *ONE* of those users,
given that the problem vanishes when those users
don't receive postings from the list.
 
One by one, set each of them back to 'MAIL' status,
make a posting to the list, and correlate the results.