PacketFence

PacketFence is an open-source network access control (NAC) system. Deployed in academic networks around the world, PacketFence is reliable, extremely configurable, and built upon unmodified open-source code (Fedora, LAMP, Perl, and Snort).

PacketFence 1.6.2

PacketFence is an open-source network access control (NAC) system. Deployed in academic networks around the world, PacketFence is reliable, extremely configurable, and built upon unmodified open-source code (Fedora, LAMP, Perl, and Snort). Documentation available here.
PacketFence ZEN 0.1

PacketFence ZEN (Zero Effort NAC) is ideal for those testing the NAC waters to get up and running with little effort. A VMware virtual appliance, it works "out of the box" with no modules or RPMs to install. Documentation available here.
dhcp-finger 1.0

Stand-alone utility to perform passive OS fingerprinting using DHCP. Documentation available here.
dhcp-finger 1.0 (OpenWrt Kamikaze)

Compiled binary to allow you to run on your Linksys WRT54G running the Kamikaze release of OpenWRT. Documentation available here.
dhcp-finger 1.0 (OpenWrt Whiterussian)

Compiled binary to allow you to run on your Linksys WRT54G running the Whiterussian release of OpenWRT. Documentation available here.

http://www.packetfence.org/downloads.html