Originally posted here by tyger_claw
[B]If you are behind aNAT router, is it even worth turning WFW on?
It depends. It's definitely worth taking additional steps if you have a wireless network, but as
HTRegz said it kinda depends on your circumstances. For my home network I take several additonal steps, because I live in an urban area with quite a concentration of wireless networks. Even though I use WPA-PSK I don't 100% trust the wireless network to be absolutely secure.

On corporate networks you usually find that Windows Firewall is turned off on client PCs because it just tends to make machines difficult to manage. In fact, the Windows Firewall product in that kind of environment can be quite dangerous.. in certain circumstances a PC can become virus infected, and the Windows Firewall can prevent administrators from accessing the PC to clean it up.