Research on using UDP to traverse NAT under P2P network environment

With the public network IP addresses offered by IPv4 closing to exhaustion, NAT technology has been used widely on the Internet, which brings about the obstacle to P2P network communication at the same time. So, penetrating NAT technology has already become the problem that must be solved by the P2P network. This paper analyzes the impact of NAT to P2P network, and introduces several kinds of methods to traverse NAT. Then, this paper detailedly analyzes the UDP punching technology, a method that uses of UDP protocol to realize P2P network traversing NAT. At last, the working process of UDP punching technology is analyzed though an example. The results verify that UDP punching technology is applied to the P2P network, which can ensure the security and the robust of network as well.