Folks, don't forget those hardware firewall/router gadgets you can get at your local computer store. By default, they don't let anything in, so very solid (that isn't initiated from behind them). The advantage is that your computer doesn't get all those zombies' messages that it then has to waste CPU cycles sorting through. I believe those can number in the thousands per hour- which I would imagine could add up to a noticable reduction in computing power.