Antinat SOCKS server
Antinat is a flexible SOCKS server and client library for writing proxy-based applications. It supports SOCKS 4, SOCKS 4a, SOCKS 5, authentication, CHAP, XML firewalling, Win32, server chaining, and UDP. It also contains very experimental IPv6 support.
SOCKS can be used to overcome some limitations of NAT, including facilites for allowing connectbacks and server-side DNS. Antinat aims to be fully standards compliant, feature rich, and have a solid API for writing standards-compliant client applications.
Connections are filtered by applying XML rules, which allow for very fine-grained control. You can filter out on the basis of addresses, ports, users, socks version, the operation requested, how the user was authenticated, and where user credentials came from.
Standard free software disclaimer: find a bug? Let us know. Want a feature? Let us know. Patches are preferred to feedback, feedback is preferred to nothing. We can't read your mind. We can't. Honest.
So without further adue, download it now.