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Posted by cyberdude on 24.03.2008 at 22:50:

Problems getting Xlite to work. - FIXED

We have set Xlite softphone up on a member of staff's laptop but it doesn't seem to work properly.

We are able to make or receive a call immediately after Xlite registers with the PBX but if you leave it for 20 seconds or so then you can no longer make or receive calls. The PBX status page shows Xlite extension as registered though.

The settings in Xlite are configured as we have our IP phone extensions configured so I can't see why we are having this problem.

Any suggestions?

Posted by Diafora on 25.03.2008 at 17:09:

This is a classic NAT traversal issue. If the laptop running X-Lite is behind a firewall, ensure that STUN or ICE is used for proper NAT traversal.

• What kind of firewall protects the network?
• When the staff member takes the laptop at home, does the issue manifest itself there too?
• Can you temporarily assign a public IP to the laptop, or place it on the DMZ of the router to ensure if the issue remains? (Also ensure its' firewall is turned on and properly activated to let the SIP and RTP packets through unobstructed).

Posted by cyberdude on 28.03.2008 at 15:05:

Yeah that's what I was thinking. The set up is as follows:

The user is a remote worker based from home. They have a ADSL modem (speedtouch 516v6) which is like a single port router / gateway. It connects to the laptop via ethernet. The modem firewall and all ports are open. The only firewall used is the WinXP firewall.

I've done some research on that modem and I have discovered it has SIP ALG which I suspect is causing the problem.

I'll report back once I have telnetted into the modem and removed the binding.

Posted by Diafora on 28.03.2008 at 15:42:

Keep in mind the SIP ALG should improve the NAT traversal, but the SIP UA should not be trying to do its' own NAT traversal via STUN or ICE.

So try to disable STUN on the X-Lite first, and see if it remains registered. Also with the SIP ALG running on the SpeedTouch, set the "audio bypass" field to No on the extension of the X-Lite.

Are the rest of the IP phones registered to your account behind any firewall?

Posted by cyberdude on 03.04.2008 at 18:05:

OK .I fixed the problem. It was a problem with the SIP ALG that was causing the problem. I unbound the SIP and now it's all working.