[PLUG] Odd email problem

[JP Vossen <jp@jpsdomain.org>]

I'm trying to diagnose an odd email problem with a GNU Mailman list. 
One list member is using Outlook to send email to the correct address, 
PANTUGGeneral@lists.pantug.org, but each message is being rejected as 
destined for PANTUGGeneral@mail.pantug.org.  Note the @lists. vs. @mail. 
parts.

We've gone so far as to sniff the outgoing traffic, but as far as I can 
tell it looks like normal SMTP leaving the local machine on the wire and 
going to the correct address.  But Postfix logs a reject to the wrong 
address.

For this, and other reasons he's switched hosting providers, and the 
problem persists.  We're not aware of any SMTP proxies, and find it hard 
to believe that a proxy would swap parts of an address...  OTOH, the 
reverse lookup of the server *is* mail. (not list.), so it's possible 
something is trying to be "helpful."  We just can't figure out what.

We've hacked around the problem by creating a local account and the 
necessary .forward file (/etc/aliases didn't work for mail domain 
reasons), but it's still really bugging me.

Does anyone have any idea how this could happen, or suggestions on where 
else to look?

Thanks,
JP
----------------------------|:::======|-------------------------------
JP Vossen, CISSP            |:::======|        jp{at}jpsdomain{dot}org
My Account, My Opinions     |=========|      http://www.jpsdomain.org/
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