This post is the result of my weekend work.

First check the wikipedia page for UDP hole punching, then this beautifully written article about Peer-to-Peer Communication Across Network Address Translators and then try this code.

So what is this all about.

Using this code you will be able to transfer files between 2 hosts located behind different firewalls or NAT routers. It requires a third host used for session initialisation. This third host is NOT a proxy, it just helps the other 2 hosts to find out about each other.

You need to run this rendezvous server for yourself, but I am trying to create a public rendezvous server.

Right now the code is in a “proof of concept” stage. I hope I will have time to polish this work.