Cisco 7811 phone not registering to CUCM 11.5

[shivani.sharma]

Trying to register few Cisco 7811 phones to CUCM 11.5. Phones can talk to the CUCM. They get the configuration/firmware files from the CUCM (also acting as TFTP server), but the phone never sends a register request.  There is no error on the phone status messages. Phone is also able to resolve CUCM hostname to correct IP address.

What could be the issue? How do I troubleshoot this issue?

[voipeee]

Hi @shivani.sharma what do you see on the phone? Can you collect console logs and attach it here.

[shivani.sharma]

Phone display just shows registration in progress and then reboots after a while and keeps repeating. How do I get console logs?

[TONY SMITH]

Do you have directory numbers configured on the phones?  SIP phones won't register without at least one DN, unlike SCCP.

[shivani.sharma]

Yes, I do have a DN associated to the phones. I have set the user to anonymous, so no user associated to the phone.

[Rajan · Accepted solution]

Can you get a wireshark capture by connecting a pc/laptop to the back of phone to see the exact communication between CUCM and Phone. This will confirm whether the phone is sending a message to CUCM and whether its an issue from phone side or CUCM.

HTH
Rajan
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[shivani.sharma]

Thanks for your suggestion. After capturing at the phone I saw that the phone was sending a SIP register request but that request never made it to the CUCM. After investigating found that the Fortigate firewall in the path was blocking it. Disabled sip session-helper on FortiGate and the phones were able to register. Thanks!!

[Ratheesh Kumar]

with SIP phones you can face unexpected behaviour, such as phones not registering and incoming calls failing. Therefore if you are experiencing problems its recommend that you turn SIP ALG off if it is enabled.

Hope this Helps

Cheers
Rath!

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