Test html

UDP Hole Puching

http://webcache.googleusercontent.com/search?q=cache:sug1DQs1x7AJ:tech.163.com/06/0206/09/2995AK7N00091JFM.html+%E9%98%B2%E7%81%AB%E7%89%86%E7%A9%BF%E9%80%8F&cd=8&hl=zh-TW&ct=clnk&gl=tw&source=www.google.com.tw

http://www.cs.nccu.edu.tw/~lien/Writing/NGN/firewall.htm

現有幾個穿越防火牆/NAT技術如下：

• UPnP(Universal Plug and Play)
• STUN(Simple Traversal of UDP Through Netwoek Address Translators)-RFC 3489
• TRUN(Traversal Using Relay NAT)
• ALG(Application Layer Gatewqy)
• ICE(Interactive Connectivity Establish)

http://zh.wikipedia.org/wiki/NAT%E7%A9%BF%E8%B6%8A

STUN实现

1.STUN Client and Server library(http://sourceforge.net/projects/stun/)
这个库实现了RFC3489中的STUN协议。其中，Client程序输出结果意义如下：
（1）"Open"表示这里的Open Internet
（2）"Independent Mapping, Independent Filter"表示这里的Full Cone NAT
（3）"Independedt Mapping, Address Dependendent Filter"表示这里的Restricted Core NAT
（4）"Indepndent Mapping, Port Dependent Filter"表示这里的Port Restricted Core NAT
（5）"Dependent Mapping"表示这里的Symmetric NAT
（6）"Firewall"表示这里的Symmetric Firewall
（7）"Blocked or could not reach STUN server"表示这里的UDP Blocked

2. reTurn (http://www.resiprocate.org/ReTurn_Overview)
实现了RFC5389中的STUN协议和TURN协议。

This project implements a simple STUN server and client on Windows, Linux, and Solaris. The STUN protocol (Simple Traversal of UDP through NATs) is described in the IETF RFC 3489, available athttp://www.ietf.org/rfc/rfc3489.txt

http://www.resiprocate.org/ReTurn_Overview

http://nutss.gforge.cis.cornell.edu//

http://www.pjsip.org/download.htm