Antinat is a flexible SOCKS server and client library for writing proxy-based applications. It supports SOCKS 4, SOCKS 5, authentication, CHAP, XML firewalling, Win32, server chaining, and UDP. It also contains very experimental IPv6 support.
This project adds database connectivity to the built in IAS (RADIUS) Windows 2000 service. This adds a great deal of flexibility for returning custom attributes, implementing custom authorization methods, etc. It includes PAP and CHAP support.