softphone not working over Cisco VPN

Posts: 2 · New Forum Member Joined: Nov 02, 2005 Posts: 2

Hi,

My company uses the Cisco VPN client for secure network access. I just installed the softphone, and it does not work when my pc is connected through the VPN. It works great when the vpn isn't connected.

What, if any, are my options?

Thanks.

Posts: 2 · New Forum Member Joined: Nov 02, 2005 Posts: 2

hi, some digging in the vonage support forum uncovered the (unconfirmed by vonage) fact that the softphone requires UDP 5060, 8000, 8001 to be open, and that these are usually blocked by corporate firewalls. put in a request to have these opened, not too optimistic though.

Posts: 1 · New Forum Member Joined: Nov 04, 2005 Posts: 1

Try starting the softphone before you start the VPN software. Checkpoint VPN is typical two services that are set to automatic at startup. I know this works for some things that my company blocks

Posts: 7 · New Forum Member Joined: Sep 24, 2005 Posts: 7

I don't have the Vonage softphone, but I've been playing around with other softphone providers and here's what I *think* the problem is.

When the softphone starts up it needs to report the IP address of where it is to the voip gateway. Without the VPN running the softphone talks to your router/firewall or to external servers to figure out what the external IP address of your router/firewall is and reports that to the voip gateway.

When the VPN starts up, you effectively have two IP addresses and two routers/firewalls. The softphone seems to prefer to talk to the VPN firewall rather than your local lan one. So it sees the external address of your company and reports that to the voip gateway. Incoming calls get routed to your company IP address, through the VPN and to the softphone. If any of the firewalls at your company or associated with the VPN on your end block the VOIP ports it doesn't work. Even if it works it adds a bunch of extra hops to the voice traffic that don't need to be there.

In my case, even starting the softphone before the VPN doesn't help because softphone software I've tried changes it's reported address as soon as the VPN comes up.

I don't know if there is a way to tell the softphone to ignore the VPN and just use my local firewall instead.

Posts: 1 · New Forum Member Joined: Nov 15, 2006 Posts: 1

I am experiencing the same issue with my Cisco VPN Client. The V-Phone works fine until I completely log into the VPN and the connection is established. The V-Phone then reports "Unregistering Service". I looked at the log files for both the Cisco VPN client and the V-Phone. It appears that the Cisco VPN client defaults to tunnel through UDP, but you can change it to TCP where it uses port 10000 as the default. I am not sure if this is the same for UDP because you do not have the option to change it when UDP is selected. The V-Phone shows multiple instances in the log file showing that its communicating with a Vonage IP address through port 10000. I thought this was the issue so I changed the VPN client to tunnel through port 9000. Even when connecting through this, the problem prevailed.

Has anyone found a solution to this? It really does sound like the answer might be the last post, but what I don't understand is, if the V-Phone prefers the IP it is getting through the VPN, why doesn't it work if you initiate the V-Phone AFTER the VPN is already connected.

Posts: 9 · New Forum Member Joined: Nov 02, 2005 Posts: 9

When are you using the VoIP over VPN you are tunneling over the VPN and then on your company's private network. A few things could be preventing this:

1- The company's firewalls could be blocking those ports (I know we do)
2 - Before you log into your VPN change your softphone settings to use the Cisco VPN Adapter. Once your on that lan device you have a better chance of getting registered because when you are using VPN you are adding another "sudo" layer of NAT: The setup goes out to be this:

ISP Address
Router
Private Home Network
then VPN address

The VPN Address gets tunnled and can sometimes confuse things as it tells all your networking on your machine to go through that interface. Sounds like what is happening is that your company's firewall is blocking the ports and maybe even the address that the softphone would use to register.