Comment by idupree
12 years ago
That's standardized as TURN, if I'm not mistaken ( https://en.wikipedia.org/wiki/Traversal_Using_Relays_around_... ). Other NAT traversal mechanisms (STUN) don't make the server pay for bandwidth. (Which methods work with TCP, in practice?)
There was a good thread on p2p-hackers a little while back. I apologize for not digging up the link but I'm on my way to bed. I think the thread was something like "state of the art NAT traversal"