Hi Andrew, On 2/20/07, "Andrew Nowrot" <andrew.nowrot(a)gmail.com> wrote: I faced a similar problem some time ago. Here are some tips based on what I have tried to solve this: - Capture the sip messages using ngrep: 'ngrep -qt -d eth0 -W byline port 5060' (of course, replace eth0 with your real iface) - Check the sdp part to see what media IP adress is advertised by each party ('c=IN IP4' line in the INVITE request and OK response.) You may have private IPs here if your sip phones are behind a NAT. - Sniff udp traffic in the port range where the RTP traffic is likely to be (I use '-s0 -X' options on tcpdump to get the payload in hex.) - If you don't see any incoming our outgoing packet then, there ay be a firewall drop issue. Hope this will help. -- Regards, -vma .