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New Member

IPC one-way audio

Hi, Can anyone please help.

We are running CallManager 3.3(5) and IPC 1.1.4 and 2.0.1. When we use on our local LAN it works fine. We can make/receive calls without any problems but when we dial-in to our CallManager via VPN client (4.7) and Cisco PIX (6.3) we experience one-way audio - we can hear the remote party but they can't hear us. Does anyone know of any setting we have to change on the PIX / CallManager to fix this. Have downloaded getIP.asp to resolve address translation issues but still no luck. Any help will do. Many Thanks ... Mazolla

New Member

Re: IPC one-way audio


I have the same problem. Somebody told me it’s a routing Problem. At the moment I have not the time to test the routes. Maybe the routes to the remote Client are only one-way.

Re: IPC one-way audio

I've had the same problem and figured it out.. It took a network sniffer to find this. The problem is a routing problem. What type of gateway is this? h.323 or Mgcp. Make sure to configure a source address for MGCP or h.323. In CM manager you point your gateway to this source address. In your PIX, make sure you add a route for the source address. Make sure you exclude from NAT. Once this is done, you should be able to hear two audio.

New Member

Re: IPC one-way audio

I have had the same problem, voice us very sensitive to NAT, and Voice and Firewalls are not really the best friends, you have to make sure the voice devices are on the same subnet ( to avoid Nat ) and if is not possible I suggest you to use a the DMZ port for you firewall and if you don’t have one try forwarding the ports to device that u are having the problem.


Re: IPC one-way audio

had a simliar issue with a checkpoint firewall. we had to open up the port range 16384-32767 and that worked.