An Explanation and Demonstration of NAT Punchthrough Using a Peer to Peer Chat Client

Many applications use Network Address Translation (NAT) punchthrough to allow clients to communicate with each other over separate Local Area Networks (LANs). The idea is to avoid using server resources by allowing clients to communicate directly. Obviously this poses some problems due to the nature of NAT. One client cannot directly communicate with another. However, Using NAT punchthrough this problem can be solved, depending on what type of routers the clients use.