LISTSERV Postmasters and List Owners:
 
   We just found a rather nasty reflector problem.  We were getting
duplicated messages on one of our lists.  The messages were repeated
every 27-30some messages.  (They weren't caught by the CRC checker for
duplicate text since that only retained the last 20 message CRCs.  I think
Eric has some good ideas on how to prevent this in the future).
 
   We found a subscription in the list of:
 
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on three of our lists.  Telneting to the SMTP port at MADRONA and doing an
expn listname  we found that each pointed directly back to the list!  Needless
to say we removed the subscriptions and served those addresses off (in case
they tried to re-subscribe).
 
   Looking at the SMTP logs showed the incoming items were from OWNER-listname
so the reflector just echoed the incoming mail using the same MAIL FROM as
the outgoing list mail.  The Helo Domain was: madrona.engr.washington.edu .
 
   I just wanted to warn others.  You might want to check any MADRONA
subscriptions in your lists...  ;-)
 
   The problem was difficult to catch because of the "distance" between
repeats.  We still don't know how it got started but it seems to have
started yesterday afternoon (our incoming mail from madrona started at
14:47 CST or 20:47 GMT).  Perhaps we were the only ones affected (the
three lists here were all part of one project, KIDLINK).  But better
safe than sorry!
 
         Marty