Starting back in 2004 Nvidia has had this on-chip firewall (part hardware -- part software) implemented on certain of their motherboards. (most of the nforce3-nforce4 MoBo's) So it has been around for quite some time. The last mother board I had, came with it, but someone warned me about the troubles it could cause and I avoided installing the drivers for it.
The technology is called ActiveArmor and that should help in a search to discover how to get rid of the drivers. This article
here might help as well if you have a Force4 MoBo.