The SIP service exposes the external network IP and port through the external network mapping, and the lower-level platform or device registers to the SIP service through the external network.
At this time, if the lower-level platform is configured with its own intranet IP, then in the INVITE, after the other party responds with 200 OK, our SIP service will send ACK and BYE to the other party’s intranet IP and port, then the other party ACK and BYE cannot be received.
After self-testing and verification, it is OK to configure the internal network IP of the lower-level platform to the corresponding external network IP. If you use eXosip, from the packet capture point of view, eXosip will register twice, and the first registration contact is the internal network IP And port, the second contact is the external IP and port, so ACK and BYE will be no problem