Over the past month, a particular list has had previously distributed mail,
regurgitated back to the listserv for redistribution. The origin of the loop
seems to be mail.industry.net.
 
This is part of a sample header on the looped mail:
 
Received: (root@localhost) by mail.industry.net (8.6.9/8.6.8) id RAA02513; Wed,
          31 Jul 1996 17:51:05 -0400
Received: from info.utcc.utoronto.ca (dbs.utcc.utoronto.ca [128.100.132.30]) by
          mail.industry.net (8.6.9/8.6.8) with SMTP id QAA03534; Wed, 24 Jul
          1996 16:34:52 -0400
 
As you can see, this mail was distributed on the 24th of July and put back
into the system on the 31st of July. Multiply this by hundreds and you can
see that a listserv can be inundated with this looping mail.
 
This phenomenom has occurred 4 times the last month.
 
Since the volume of looped mail exceeded the max number of messages, holds
were multiple during the day. This value was increased from 50 to 100.
 
The list has 5 or 6 subscribers that share the domain which is looping the
mail. The looped mail retains the original posters name but with the
X-Deliver-To: tag of the person who the mail was delivered, is appended to
the looped message header.
 
Over the short term, quiet killing the 5 or 6 subscribers has been
tried....but with spooled mail, it may take days to see the results...since
the looping mail is tying the system up.
 
The brute force method seems to be the filter command.
 
The topics for discussion:
 
How is looped mail able to repost to a send=private list?
 
How has this phenomenon been solved in the past? Support at Industry Net has
been notified.