Mysterious header munging

[Steven M. List]

A friend and I have experienced an interesting problem, and I'm not sure
whether it's his system or mine (but you KNOW whose I really think it is!).
When I send mail to his system (and sometimes to myself through his system
for testing), SOMEtimes the From: and Reply-To: lines are munged.  They
are ALWAYS being rewritten!

He is running SCO UNIX and the supplied MMDF for the transport agent.
His front end (as mine) is ELM 2.3 PL4.  My system is running Smail 3.x,
and has no apparent problems with ANY other system (so there!).  I've
noted that some other systems (like Apple) also rewrite these headers,
but am not expert enough in the transport agent area to know why or what
or how.

So the question is:

    Can anyone give us any pointers on what might be causing these
    problems?

The specific symptom is that the path from his system to mine is changed
to be:

    itkin at guinan.mrspoc.ames.uucp

Which is DEFINITELY not correct!  :^>~

Elm quite nicely adds my Reply-To: line, which starts out as

    Reply-To: itkin at guinan.Transact.COM (Steven List)

and I've checked the outgoing files before they leave both guinan (my
node) and mrspoc (our domain server), and they are fine.

Any hints?

Steven
-- 
 +----------------------------------------------------------------------------+
 :                Steven List @ Transact Software, Inc. :^>~                  :
 :           Chairman, Unify User Group of Northern California                :
 :     {apple,coherent,limbo,mips,pyramid,ubvax}!itkin at guinan.Transact.COM    :