NAT(Network Address Translators)，网络地址转换：网络地址转换是在IP地址日益缺乏的情况下产生的，它的主要目的就是为了能够地址重用。NAT分为两大类，基本的NAT和NAPT(Network Address/Port Translator)。

最开始NAT是运行在路由器上的一个功能模块。在这里我就用自己实现的一个源代码来说明UDP穿越NAT的原理。-NAT (Network Address Translators), Network Address Translation: Network Address Translation in the case of the IP address of the increasing scarcity of the produce, its main purpose is to be able to address reuse. NAT is divided into two categories, basic NAT and NAPT (Network Address/Port Translator). Initially NAT is running on a router modules. Here I use myself to achieve a source code to illustrate the UDP Through NAT principle.