hole-punching

I try to make a P2P Program and need help with getting through the NAT of the clients. I have read many questions here on stackoverflow, but i never got what the drawbacks and benefits of all the Methods to get through a NAT are. How many routers support which methods? Which methods are commonly used by the big companies? (BitTorrent, TeamViewer,...) What are the drawbacks/benefits of the three methods i listed and which else exists? UPnP requires software support in your router. Even when routers have it, it's sometimes turned off due to security concerns. STUN uses a simple public server to

I'm trying to add networking over the internet to my game, using Peer to Peer. I have already implemented a LAN only version, which uses .NET's peer to peer classes to connect within the local network. I realized I need to use UDP hole punching in order to establish a connection to other clients that are behind a firewall. This is how I have started to implement it: The server is a HTTP server using very simple PHP scripts to get the job done. register name on server, sending the private ip address and port as a GET variable when the server gets a registration request, it will save the public

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 to allow direct voice contact between two players, for example, or any other client plugin they may have installed which don't need server interaction (like playing some kind of random game between the two). The server can be there to help setting up the connection. From duskwuff's answer, I got several leads: http://en.wikipedia.org/wiki/STUN which describes an algorithm to do that, and http://en.wikipedia.org/wiki/UDP_hole

Question is below. Here is my current test code which did not succeed. static void Main(string[] args) { if (args.Count() != 3) { Console.WriteLine("Bad args"); } var ep = new IPEndPoint(IPAddress.Parse(args[0]), int.Parse(args[1])); var lp = new IPEndPoint(IPAddress.Any, int.Parse(args[2])); var s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); s.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true); s.Bind(lp); var c = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); c.SetSocketOption(SocketOptionLevel.Socket