Phill Edwards put forth on 8/8/2010 11:14 PM:
Originally 192.168.2.1 couldn't see the 192.168.0.0 network but with some help from the Smoothwall forums I have fixed that.
One more example of DMZs creating more grief for a newbie than benefit...
The Smoothie has those ports open to your web server, but it's not routing the packets to your dovecot server. We know the ports are open because you get "Connection refused", which is what Linux does when no service daemon is listening and responding on a port. Translated into newbie speak: It's the Smoothie box itself which said "Connection refused" to your web server.
So, now you need to learn about Smoothie/Linux IP routing. The guys on the forum you mentioned should be able to assist. That's a better place to get assistance, as your problem has nothing to do with Dovecot.
Good luck.
-- Stan