VoIPong is a free VoIP sniffer that detects all Voice-over-IP (VoIP) calls and gateways on a pipeline and produces audio files. It supports several types of VoIP protocols: SIP, H.323, Skinny Client Protocol, G711, RTP and RTCP.
A liveCD version, based on the FreeSBIE project, is also available. It has a pre-installed VoIPong release along with several boot-time scripts for configuring the OS and VoIPong.
VoIPong LiveCD
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