In the Client and the Client B know each other's (public IP: port) for x] [write this, at that time A to B contract first, consider the socket programming is to have two tuples (destination IP and port), the dualistic group or there is no way to fill in at this moment, the destination IP is obviously A NAT B public IP, but the port should be A process of port, rather than x.p ort, because x.p ort are mapped port of the network host, that when the package sent to the corresponding NAT B server was obviously not say x.p ort, corresponding NAT server B how do you know which (B) sent to the host?

CodePudding user response:

Make hole need to be established by a middle server first shake hands, so you can get the communication on both sides of the mapping for two tuples (IP, PORT),