SIP协议中穿越对称型/非对称型NAT防火墙的多种实现方法，解决私网内部的防火墙穿透问题。-SIP cross symmetric / asymmetric NAT firewall multiple solutions, private internal network firewall penetration.

基于sip协议的VoIP、视频会议源码，对防火墙穿透协议支持较好，跨平台，支持Linux/Unix,Wingdows,CE,Symbian等,Sip agreement based on VoIP, video conferencing source of support to better penetrate the firewall, cross-platform support for Linux/Unix, Wingdows, CE, Symbian, etc.

轻量级sip网络电话服务器，可支持网络穿透，运行于防火墙后端-Lightweight sip Internet phone server support network penetration, running behind a firewall