nat-traversal

I am trying to make an online game application, which communicates with another pc peer-to-peer over the Internet. Since both pc's are likely to be under NAT, and since I cannot afford an external server, I thought the only way is to use free STUN and TURN server, such as Numb . However, after some research, I couldn't figure out how to use those servers to make a connection. Is it really possible to use only those servers to do it? If it is, how would you do that? Or is there an easier way of doing that? I can use either UDP or TCP for this. Take a look at the Internet Gateway Device Protocol

I've seen and read a lot of similar questions, and the corresponding Wikipedia articles ( NAT traversal , STUN , TURN , TCP hole punching ), but the overwhelming amount of information doesn't really help me with my very simple problem: I'm writing a P2P application, and I want two users of my application behind NAT to be able to connect to each other. The connection must be reliable (comparable to TCP's reliability) so I can't just switch to UDP. The solution should work on today's common systems without reconfiguration. If it helps, the solution may involve a connectible 3rd-party, as long as

How does one PC connect to another over the internet to another PC? An example would be a program listening for connections on PC 1. PC 1 sits behind Router 1. PC 2 has a client program trying to connect to PC 1. What is the correct technology/technique to use as the listening program in this situation? This article by Brian Ford explains how peer to peer communication across NATs work. Most routers also expose a Universal Plug and Play interface (uPnP) which can be used for port forwarding and NAT traversal. You should also check out the STUNT library which is an easy to use NAT traversal

I've come across an interesting problem. Basically I have 2 mobile phones that are both behind NATs. I want to communicate directly between the 2 devices using UDP. I know if I initiate a connection from the phones to a server then I can push data back down that connection to the phone (ie send it back from the same port that received the message to the same ip and port that it was received from). So I can easily communicate between the 2 devices by connecting both phones to the server. Then sending data to the server and having it re-routed back to the phones. This bypasses any NAT traversal