How dangerous is it to have my IPv4's firewall disabled?

[Davcoll]

So a while back ago me and my friend were having trouble connecting to one of our listen servers on certain games. We tried everything until eventually I found out that by disabling my IPv4 firewall on my gateway's login screen that it fixed the issue.

So my question is how safe is it to have the FW disabled and what are the risks I run by having it disabled. Keep in mind that I'm not an expert at networking, so try to keep the explanation simple if you could. My router is an Arris TG862G-CT. Pic - http://i.imgur.com/2B9HadH.jpg

 

[bill001g]

It likely makes almost no difference. The key so called firewall feature you get for free on every router is the NAT. This is the same as a firewall filter that prevents any traffic coming in from the outside that was not first established from the inside. So if you machines in your lan did not talk to something on certain ports on the internet then the traffic will be dropped.

Almost all other firewall protection is mostly to protect the router itself from attack and those are mostly denial of service things.

It would be different if you had port fowarding or used the DMZ options then again device you expose to the internet like that you normally have higher than normal firewall option enable on those hosts so they only accept traffic for the application they are running.