I have a client with an issue receiving and making calls from a 8841 phone registered to CUCM 12.5 server. The phone, when placed in a directly connected subnet, works fine. However, it's final location is a building connected to the main office (where the CUCM server sits) by 2 SonicWalls. So the config when there are issues is:
CUCM -- SonicWall -- VPN -- SonicWall -- 8841
The phone has the following behavior:
- It registers with the CUCM server
- When dialing another phone by taking the handset off-hook calls do not go through. I believe the server is not receiving the digit by digit numbers.
- When dialing another phone with handset on-hook, calls go through OK, so enbloc dialing is working?
- When a call comes into the phone, it never rings. The RTMT log for the failed inbound call has a termination cause of "CCM_SIP_503_SERVICE_UNAVAILABLE"
The phone shows as registered in CUCM and pings are going between subnets so I don't think it's a routing issue but rather a SonicWall issue. I don't manage or have access to the SonicWall but would like to give the person that does manage it some direction on what to look for. He says everything is being allowed through. The SonicWall is running version 6.5.
Any ideas ?