Network Address Translation(NAT) causes difficulties for peer-to-peer(P2P) communication,and therefore NAT traversal has become a problem to be faced and solved by P2P application .

• 网络中存在的Network Address Translation(NAT)使得Peer-to-Peer(P2P)通信存在极大的困难,因此穿透NAT已经成为P2P应用必须面对和解决的问题。