I recently received a complaint from the owner of a list which is set to 
Reply= Sender.  When a subscriber from AOL posts to the list, all the 
copies to AOL subscribers bounced with this error: 
http://postmaster.info.aol.com/errors/554rlysn.html, "This error 
indicates you are sending email as AOL.COM, or one of its affiliates 
from an unauthorized IP address."  It's true that with Reply= Sender 
Listserv does that, but what's the alternative?  Is there a way to 
prevent AOL from bouncing the mail while keeping Reply= Sender?

Peter