CME and SIP calls through VPN

Answered Question
Mar 26th, 2008


I have configured CME 4.1 to act as SIP Proxy Server,Configured it corectly so X-Lite SIP Softphone can register with it. Inside LAN network X-Lite to X-Lite calls function without the problem, but:

I connect through VPN to my LAN and register X-Lite with CME (extenssion 66) without any problem.

The other person also connects to our LAN through and registers his X-Lite with CME (extenssion 55).I would like them to talk to each other.

The problem is following. When any of us try to call eachother, the X-Lite Rings, and when a call is answered it immediatly drops with error "Internal Server Error". This is SIP 500 message.

Does anybody has a clue why is this happening and how it can be solved.


Correct Answer by Paolo Bevilacqua about 8 years 11 months ago

Call from 2222 tries to use an unsupported speex codec. Please configure x-lite to use g711u only.

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Overall Rating: 5 (1 ratings)
alicicmirzet Wed, 03/26/2008 - 07:31

yes, I have configured it with the command

voice class codec 1

codec preference 1 g711alaw

codec preference 2 g711ulaw

and then under voice poolvalso

voice-class codec 1

alicicmirzet Wed, 03/26/2008 - 07:39

I have also to mention following.

When I connect from one location using VPN and registering to CME with IP Communicator and from other Location using VPN and registering X-Lite, calls can be placed between IP Communicator and X-Lite.

The only issue is X-Lite to X-Lite (SIP to SIP) calls


Paolo Bevilacqua Wed, 03/26/2008 - 07:44

Should not be necessary, but please also configure

voice service voip

allow-connections sip-to-sip

Correct Answer
Paolo Bevilacqua Wed, 03/26/2008 - 08:43

Call from 2222 tries to use an unsupported speex codec. Please configure x-lite to use g711u only.

alicicmirzet Wed, 03/26/2008 - 12:23


In X-Lite I have set only G711a and G711u codecs, but it was not working.

When I set only G711u codec it worked.

Thanx very much

I will grade it with 5 ;-)



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