Encryption between 2 Ip Phone

Unanswered Question
Feb 6th, 2008


Is it possible to encrypt communication throught 2 IP Phone interconnect with a CME ?

My IP Phones are 7906 and 7911.

Thanks in advance


I have this problem too.
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ogor Fri, 02/15/2008 - 02:32

I'm in CME 4.2 with 7942, 7911 and 7906 IP Phone and when I put the

ephone xxx

device-security-mode encrypted

command then the IP Phone could not register on the CME

=> Here is the message on the IP Phone " Registration Rejected : Max Phones ...3

and the one on the CME

Feb 15 19:31:09.091 UTC: %IPPHONE-6-REG_ALARM: 24: Name=SEP001EF7C2BC4D Load= SCCP42.8-3-2S Last=Phone-Reg-Rej

Feb 15 19:31:10.087 UTC: %IPPHONE-6-REG_ALARM: 22: Name=SEP001EF7C2BD1E Load= SCCP42.8-3-2S Last=Reset-Reset

when I remove the device-security-mode encrypted, the IP phone register immedialtly but without sRTP ?

any idea

thanks in advance for your help


MARTIN STREULE Wed, 02/20/2008 - 15:45

You have to do the steps mentioned in the doc in the other post. It's more then just enter the one command...

Phone Authentication

•Configuring the Cisco IOS Certification Authority (required)

•Authenticating Certificates for Server Functions (required)

•Configuring Telephony-Service Security Parameters (required)

•Configuring the CTL Client (required)

•Configuring the CAPF Server (required)

Media Encryption

•Configuring Secure Calls Between Cisco Unified CMEs Across an H.323 Trunk (required)

•Configuring Cisco Unified CME SRTP Fallback for H.323 Dial Peers (optional)

Good luck,


joelau007 Tue, 02/02/2010 - 06:45

Has anyone found the solution for this ? I'm looking at exactly the same error when "device-security-mode encrypted" in CME7.



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