bsdproxy is a generic, event-driven proxy designed specifically for the
BSD platform.  It uses the kqueue()/kevent() system calls to determine
when to relay data from one side of the connection to the other.  It also
uses GLib (http://www.gtk.org) data structures and memory management 
functions to optimize steady-state performance (minimize unnecessary 
memory allocation/deallocation).  

bsdproxy has been used to proxy HTTP, HTTPS, telnet, and mysql without
any problems.  It should be able to serve as a transparent proxy for 
anything over a TCP/IP connection.

WWW:		http://sydney.daveb.net/bsdproxy/
Author:		Dave Bailey <dave@daveb.net>
