Communication between two computers without opening ports, using a third computer to set up the connection

Question

Let\'s say I have a server, and two clients connected to it. (via TCP, but it doesn\'t matter)

My goal is to allow a direct connection between those two clients. This is

Answer 1

A few links to projects that might be of interest or helpful:

• http://sourceforge.net/projects/stun/
• http://udt.sourceforge.net/
• http://www.telehash.org/