Postfix Spam Filter using Ubuntu Dapper question
I've successfully completed the Howto for this particular solution and it's working pretty good so far. I am curious about where it states that I have to open the following firewall ports; 24441 for pyzor, 6277 for DCC, 2703 for Razor and 783 for SpamAssassin. It also only states that I have to open outgoing and incoming on 24441 for pyzor but doesn't specifically state whether the others need to be outgoing/incoming for DCC, Razor, and SpamAssassin.
First, is this regarding iptables, or my hardware firewall on the perimeter of my network?
Next, I've scoured the internet for a couple of hours and I cannot find any information directly related to why these ports are being opened. I'm assuming its for getting updates of spam signatures an similar things, but I'd like to be sure before I decide to leave these ports open. Can anyone point me to some links? Or if you're feeling particularly benevolent a direct answer?