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New Member


Trying out the IP softphone over DSL. Problem is when I place a call I can hear dial tone, however, after the call is placed and connects the other party can hear me but I can not hear them (at all).

Also, is there a limit to how many softphones you can have on a call manager.?

New Member

Re: Softphone

You stay using softphone over vpn client or NAT????

Thys is one-way audio, you hear dial tone, because signaling is h225 and h245 communications. Audio run over rtp (UDP) and have problem with NAT.

This url have more information about h323 over nat.

Best Regards

Joao Medeiros

New Member

Re: Softphone

I have run into this same problem using the softphone and Cisco VPN client. The problem is that during the RTP setup, the softphone registers it's IP address as the first IP address it finds on the PC, which is the IP address on the local network, not the IP address of the VPN interface. And of course, the other device cannot route to that address.

In the Softphone, under settings, you can manually set the IP address to use. It's on the Audio tab, under Netrok Audio Settings. You can specify the address from a dropdown list of addresses, but that gets reset when the VPN connection is lost. The best way to do it is to place the file getIP.asp on a internal webserver and then specify that URL on the Automatic selection option. The getIP.asp simply returns the source IP address the client when queried. I beleive this file can be found in the install files for the softphone.