How can I get a full pcap/cap trace to sniff all sip and RTP packets?

7. Troubleshooting Troubleshooting
1

while troubleshooting a call, I realized that tcpdump command doesn’t record or sniff the RTP packets on the voip0 port.

How can I get a full pcap/cap trace to sniff all sip and RTP packets?

2

You need to use tbrouter application to get the full trace:

VoIP Ethernet Capture on FreeSBC and ProSBC - TBwiki (telcobridges.com)