[Mailman-Users] specific (1) LHS and (2) sender rules to frustrate spam/phishing

[Stephen J. Turnbull]

Rich Kulawiec writes:

 > Any incoming mail message whose putative sender matches:
 > 
 > 	do-not-reply@
 >
 > and which is directed to any of the Mailman standard aliases can
 > be rejected (not bounced [1]) with SMTP status 550 (extended status
 > 5.7.1) since either:
 > 
 > 	(a) it's a forgery, therefore there's no point in letting
 > 	    Mailman attempt to emit a reply -- or even in accepting
 > 	    the message to begin with.
 > 	(a) it's not a forgery, therefore there's no point in trying
 > 	    to reply to it.

You have to be careful, though.  For several years on one of my lists
I had a subscriber whose address was something like (I don't recall
exactly) "nobody at not-a-real-address.somewhere.net", which was a
perfectly valid address and at which he/she/it did receive mail and
from which he/she/it would reply.