Block port 25

From:	Jason King <jking at informs dot com>
To:	m0n0wall <m0n0wall at lists dot m0n0 dot ch>
Subject:	Block port 25
Date:	Mon, 28 Nov 2005 13:04:10 -0600

I have a WAN, LAN, and DMZ on my m0n0wall. I want to block all SMTP
traffic from the LAN going to the internet, and disable all SMTP traffic
from the DMZ going to the internet except for one host on the DMZ (the
mail server).

Basically, I don't want any machine sending SMTP packets out to the
internet except for one. What rules do I need to add?

Jason