On Dec 6, 2006, at 5:55 PM, Kenny, Melissa S wrote:

> I would check the header of the message the subscriber is trying to  
> send
> to see if the From address matches the address they used to subscribe.

While you're looking in the header, check for a "Sender:" header.   
LISTSERV uses that, if it exists, in preference to the "From:".

Bill