Collate LISTSERV's log with SMTP's.  Depending on source
routing, you might need to then pursue at another host.
 
One of my "favorites" is when a incorrectly configured
MTA neglects to append the HLQF to a host name.  LISTSERV
then likes to think of this as a Bitnet node.  Subscribes
the person, then it bounces, and auto-deletes.
 
(I think this is a form of listserv-selfabuse).
 
Using 'confirm= yes' only helps slightly in that scenario.
 
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