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IP Communicator via VPN not able to receive calls

Hi there

We have an Intel VPN client installed on a PC.

IP Communicator registers fine with Call Manager at the other end of the VPN. It can also place outgoing call.

If a call arrives and I try to answer, the caller gets a busy tone; the call never connects into IP Communicator.

Did any of you had this problem before?

How about in general having a skinny node at the other end of a VPN?

I know this works fine with PIXs. What about with other VPN solutions? Is skinny affected if it goes through a NAT/VPN tunnel?


Super Bronze

Re: IP Communicator via VPN not able to receive calls


You'll need a VPN solution that gives an address to clients that is routable - i.e. new unsolicited UDP streams can get back to the client as calls are set up, as well as new TCP connections for call setup.

You can get problems where IP Comm picks up the local LAN IP and uses that as it's address in call setup messages, in these situations you need to set the actual VPN address in the preferences in the app, or use a URL that you returns the IP of the client dynamically.

This is basically because (as you mentioned NAT) most NAT systems will NAT the network-layer IP address, but not the addresses embedded in higher layer protocols (i.e. SCCP) - PIX's have (I believe) a fixup command that allows them to NAT the addresses in SCCP packets.


Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!