Why does Zfone show the IDLE status during some VoIP calls?
Some VoIP clients attempt to traverse NAT routers by sending RTP voice and video packets through TCP instead of UDP. This protocol tunneling violates the IETF standards for VoIP, which require that RTP media packets be sent over UDP. Zfone assumes that RTP will be found only in UDP packets, and thus will not detect RTP sent through TCP. In that case, Zfone’s GUI displays the “Idle” status during a call, and does not engage the ZRTP protocol. Sometimes the packets are going through a media relay which converts them to UDP for the other party, whose Zfone client can therefore see the media stream, but searches in vain for the idled ZRTP peer and displays the “NOT Secure / No ZRTP Peer” status. If this happens, here are a couple of workarounds: 1) The best solution is to move one of the parties’ computers (in particular, the one that displays IDLE) off their local network to an external IP address, thereby simplifying the NAT traversal problem. Even better, move both computers to external
