Nick Carrol wrote a tutorial about allow the notifications package mail handling with postfix on MacOs X here
http://www.weg.ee.usyd.edu.au/people/ncarroll/ref/postfix-howto
The original thread is here
https://openacs.org/forums/message-view?message_id=203904
As Mark said configuring qmail to handling incoming mail from forums reply is very easy and it works on default install of forums package.
I have a "catch all" account for my domain and create a file
/var/qmail/alias/.qmail-notification-default
with this one line content:
&service0@mydomain
i am supposing here catch all account for mydomain is service0@mydomain, there is a /home/service0/Maildir readable by the aolserver user and notifications package parameters are configured as in Nicks' tutorial
