- Firmware version: Any
- Model: S-Series
The client report he could not register the extension on his IP phone via VPN network. The ping is good from IP phone network to PBX network.
1 - In PBX log, it shows no REGISTER packets from IP phone.
2 - PBX firewall was disabled.
3 - The SIP log captured on IP phone shows no response from PBX.
Therefore, the problem should be the network, firewall blcok or NAT settings of the router.
However SIP Transmission option on SonicWall has been disabled.
The client's IT disabled the App Control for SIP Register packets. Then the registration became normal.