Tony:
 
The "net" is a very dynamic place.  I co-operate an international
list called INFOSYS that has about 5000 subscribers.  Every few
weeks we put out (distribute) a posting.  I would say about 1%
are returned with error messages similar to what you have
documented, as well as "user unknown."  We generally delete those
userids.  In the intervening weeks, more users subscribe and
unsubscribe of their own accord.  The next distribution, the same
kind of per centage are returned.
 
Pragmatically, this is the way it is.  If you are reading
documentation, postings, listings, whatever, you are going to
encounter problems when you try to use those addresses.
 
Take a look at the RECEIVED headers in the message that you
posted to me -- each RECEIVED line represents one or MORE
computer processes that were invoked.  Each one is an opportunity
for things going awry.  These "things" are maintained by human
beings with various levels of trust, expertise, or interest.
 
Sometimes I'm amazed that things work at all.
 
--  co-owner:   INFOSYS, TQM-L, CPARK-L, ERAPPA-L, JANITORS, LDBASE-L, et -L
URL:mailto:[log in to unmask]                       "BEEP if you luv LDBASE"