Going back through old mail, I found the letter attached below, regarding
looping mail between a LISTSERV list and a userid in the .UK domain (we all
know of the friendly english mailers, huh ? >:) )
 
In this site's case, all bounced mail comes from a specific userid (FAILREPTER)
so serving off this userid would break any loop from PHOENIX.CAMBRIDGE.AC.UK.
 
Now the question is: do other .UK sites have similar mechanisms ? (Then,
perhaps we can add a fixed list of served off userids to a sysvars file)
 
Or better yet, is this all still necessary ? (Perhaps Eric has already done
his magic on the incoming mail parser and no more bounced .UK mail loops)
 
Juan
 
----- Forwarded Mail Follows -----
Date:       Thu, 29 Mar 90 15:54:28 BST
From:       Ken Warner <[log in to unmask]>
To:         postmast@TECMTYVM, scheutje@HWALHW50
Subject:    looping LISTSERV discussion
Message-ID: <[log in to unmask]>
 
We (PHOENIX.CAMBRIDGE.AC.UK) recently rejected a large amount of mail
sent on the POLYMERP list to our user CJGP, who is away.
 
Our failreports used the 'Sender:' information from the received mail,
which is the correct approach.  Unfortunately because of an incorrectly
configured LISTSERV somewhere it seems that our failreports were
broadcast to the list.
 
[log in to unmask] sends ONLY fail reports.  It is
entirely reasonable to configure individual LISTSERV systems so that
this username cannot broadcast to a list, if that is the only means
available for breaking the loop.
 
Ken Warner - PostMaster.