I have a Debian 5 "Lenny" server with Postfix, Amavis, ClamAV, SpamAssassin, and Courier-IMAP. It has been giving me trouble from the start, but it works most of the time, with the exception of randomly queuing messages. I will attach my postfix configuration files, and the mail.log. I use MySQL for virtual mailbox mapping. I'm in Africa using a VSAT, but I don't have power, so it will be 12 hours before I can respond. Thanks in advance.
Apr 2 18:38:06 meinkleinewelt postfix/error: 55BC9FDAB4: to=<firstname.lastname@example.org>, relay=none, delay=196835, delays=196833/2.1/0/0.07, dsn=4.3.0, status=deferred (mail transport unavailable)
That error repeats for every mail message that didn't make it into a local user's mailbox, or out to someone else's email around the world.
I would actually prefer removing Amavis and ClamAV, as they eat up most of my memory.
All of my config files (copied to a webserver directory, it would take me forever to attach and upload): http://www.wfto.cc/mailsrvconfig/