[plug] Firewall on gateway

[Rennie Barnett]

Here at work we have a debian box acting as a gateway & DHCP for the rest of 
the office. All works a treat on old scrounged hardware, very reliable...as 
apposed to the XP file server...

Anyhow I've been able to get Gatekeeper to firewall everything except SSH and 
keep on NATing but I seem to be getting significant traffic on unusual ports 
like 2206 & 3541 etc..

My understanding of networking is basic so maybe I'm off the track when 
thinking that it's suspicious to see all this traffic on ports other than 80 
for what is a very basic internet connection (HTTP, FTP, mail).

Is it a bad idea to block OUTPUT, FORWARD and INPUT on a whole bunch of these 
seemingly unnecessary ports?

Rennie