Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

VOIP over VPN no audio

I'm using Netmeeting to make a call using the Callmanager as a gatekeeper.

When in the office, I can make calls to internal and external numbers. However, when I am at home and I am connected via VPN, when I make a call there is no audio on the receiving end.

Any help would be greatly appreciated.

6 REPLIES
New Member

Re: VOIP over VPN no audio

Please be sure the RTP ports are open in the network...

the set up of the call may not be blocked, but the UDP ports for RTP voice may be...

16383-32767

Jeff

New Member

Re: VOIP over VPN no audio

The reason this may not be working is because of NAT. H.323 does not work (very well) with NAT. When using nat and VOIP once side hears the audio and the other side does not. So may want to check to see if you are using NAT on your VPN connection.

New Member

Re: VOIP over VPN no audio

Thanks, you were right. When I removed the NAT I was able to hear both sides of the call. Any suggestions on how to continue to use NAT and voip?

New Member

Re: VOIP over VPN no audio

Check the codec being used as well. They need to match.

New Member

Re: VOIP over VPN no audio

We've not been able to get NM to work with anything but G.711 u/a. So, your VPN has to sustain 80 kbps if this is in fact true. I don't recall, but this may be in fact 80 x 2 for full duplex.

New Member

Re: VOIP over VPN no audio

We have had the same problem with a vpn-3030 and IPSEC client. The app we are using (Lucent Softphone) connected to the phone switch, but wouldn't pass audio. Just for fun, we tried connecting with a pptp tunnel, which allowed us to use the app without a problem. During consultation with Lucent, we were told this is a common problme with IPSEC vpn's and h.323 traffic. We are still working to find a solution to this as the PPTP tunnel isn't what we want to use. You might want to try this and see if it resolves your problems.

411
Views
0
Helpful
6
Replies
CreatePlease login to create content