这种NAT内部的机器A连接过外网机器C后,NAT会打开一个端口.然后外网的任何发到这个打开的端口的UDP数据报都可以到达A.不管是不是C发过来的-such NAT internal machinery A connecting machines over external networks C, NAT will open a port. Then external networks to any of the open ports of UDP datagrams can be reached

一款监控tcp/udp的程序，编程语言为VC，很适合初学-tcp / udp procedures for the programming language Visual C + + is well-suited to beginners

用Visual C++编写的UDP客户端程序。