I'm going to go a bit out on a limb and say that what your friend was talking about is what is being sold as a hardware firewall, of a sort that is built into many routers. Netgear and Syslink are 2 that I know of offhand and they are configurable to some extent to help block garbage from your computer. There is some added security advantage to using one in that a router will "buffer" your computer by chaining 2 IP addresses (1 for the comp and 1 for the router). I realize that I'm putting this a bit simplistically but this is the way I understand it. Needless to say, you should take anything you're told and double check it by doing a bit of research. That's why I've given you the 2 manufacturers names above. ABSOLUTELY, DON'T RELY TOTALLY ON WHAT SOMEONE TELLS YOU! Check things out for yourself. Good luck.
L