[Mailman-Users] determine the sender's email address?

[Jennifer Oxelson]

Hello,

How does Mailman recognize/determine the sender's email address?  E.g., 
FROM, REPLY-TO, RECEIVED, etc?

I see a similar question was asked before, but it appears that it was 
never answered:
[Mailman-Users] Recognize REPLY-TO as a subscribed user?
http://mail.python.org/pipermail/mailman-users/2001-January/009105.html

Also, has anyone ever encountered any issues with spoofing when 
configuring the sender filters of a list to accept/reject addresses via 
a specified domain?  E.g., Mailman FAQ Entry #3.33:  How do I accept or 
reject all addresses from a particular domain?  
(http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq03.033.htp)

Thanks