Step 1 Capture network packets and view the SIP call process.
The peer end returns the 200 OK message. The call is set up successfully.
According to RTP streams, IP address 192.168.1.43 sends media information to IP address 10.200.200.243, but no response is received.
According to SDP messages, the media IP address used by the FastCo PBX is 10.200.200.243.
Step 2 Ping IP address 10.200.200.243 using ICMP on the local terminal.
The IP address cannot be reached. As a result, neither the calling or called party can hear each other.
Step 3 Add a static route on the router. The fault is rectified.