Cisco ip phone over VPN has problem

[yeharold94@gmail.com]

I am trying to set up an IP phone over VPN; the topology is attached. In location A, I can reach file server from location B and DNS server in Location C, and I can ping and telnet to CME by 10.0.45.0/24.

But my phone can not register to CME, and my phone shows the information above

I have no idea why could someone help?

[Jonathan Schulenberg · Accepted solution]

To be clear: the phone itself is not attempting to function as the VPN client, correct?

I suggest starting by ruling some factors out. For example, Does the phone work is placed at the same site as CME? If yes that would suggest a routing or protocol inspection problem on the firewall/VPN appliance. If not then you may want to start here: https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/troubleshooting/guide/ts_phreg.html

[yeharold94@gmail.com · Accepted solution]

Hi, thank for help me, it works when it is placed at the same site of CME,  I think it may be the protocol inspection problem as well, because I can telnet to the CME from  location A. meanwhile, when I use compute's VLAN for phones, it worked for a while, it could registry to CME. DO you have any idea about how to fix this problem?

Thank you