虚拟专用网络（简称VPN)指的是在公用网络上建立专用网络的技术。而这篇对于VPN的关键技术分析有利于我们在进行程序开发时有更好的针对性。-Virtual Private Network (abbreviated VPN) refers to the public network to establish a private network technology. And this analysis of the key technologies for the VPN will help us