基于Netfilter的SIP安全网关设计及实现

Design and implementation of SIP security gateway based on Netfilter

针对目前较为关注的VoIP中的SPIT问题,提出了一种基于Netfilter模块的SIP安全网关的实现方案,该方案合理利用了SIP中的重定向、呼叫转移等功能,并借鉴了黑白名单、图灵测试、行为特征分析等技术.实验表明,该方案对垃圾电话有一定的防御能力,尤其是机器形式的垃圾电话,但对于人工的呼叫会有一定的缓冲期,并且对合法的用户会有一定的打扰.

With the development and extensive application of VoIP （ voice over internet protocol）, the SPIT （ spare over internet telephony） has become an important issue. This paper designed an application layer SIP （system in pakage） security gateway based on Netfilter. This gateway combines the black and white lists, Turing Test, behaviour character analysis and other technologies. Experiments show that this security gateway has a good effect in the prevention of SPIT.