[Mailman-Users] Mailman "To" address changes when posting

[Stuart]

Hi All,

I have just installed and configured mailman and it's all functioning
fairly well, but I still have the following problem.

When a user posts to the list they use listname at lists.domain.com.au . I
have setup an MX record for this subdomain, and configured sendmail do be
the local MTA for lists, and that is all working correctly in and out.

However, the the real FQDN of the server is "proxy.domain.com.au" and even
though emails are addressed to listname at lists.domain.com.au, they appear
in your inbox as listname at proxy.domain.com.au.  Is mailman changing this
in transit or is it somewhere else?

I have configured masquerading on the sendmail server to make
lists.domain.com.au the default domain for all mail sent via this server.
This works for outgoing messages, but incoming messages are being changed
somewhere.

I have configured "Mailman/mm_cfg.py" to use lists.domain.com.au as the
default domain for the web interface and email. What am I doing wrong
here? I apologise if this has been covered. I did a lot of searching
before I came here.

Server: Fedora Core 3
Mailman: mailman-2.1.5-32.fc3 (from rpm)
Sendmail: sendmail-8.13.1-2

Any suggestions would be much appreciated,

Cheers,
Stuart