Actually two ways Kip. You are correct in the first assumption, the second is when playing online game (DoD) My cable connection is brought to a stand still. The server does not go down just me. Any advice is apperciated.
NukeNabber sets itself up to listen on TCP and UDP ports commonly attacked over the internet. A total of 50 ports can be monitored simultaneously. ICMP dest_unreach attacks are now logged. It is designed to give you the information you need in order to trace an attacker including a method of finding an attacker's nickname on IRC (mIRC, VIRC and PIRCH clients are supported).
Don't worry about your router/modem being scanned by Code Red. It can only harm the machines that have unpatched IIS running on them. Infact you are more secured with the router cause it blocks all the ports for you and drops the useless packets right at the connection
If you are bothered about the activity light blinking all the time then get a hammer and...