I manage to follow the Remote Worker example to simulate the SIP registration and make calls through two soft phone.
However, the RTP didn’t go through the FreeSBC successfully. The packet capture shows that the RTP has not hit the FreeSBC but leaving a suspicious ICMP - Destination unreachable (Port unreachable) with RTCP message inside.
I suspect the RTP port is not opened when early media is passing through, thus blocking the entire RTP stream. Any ideas how this can be solved?