vanguard wrote:We have set up the VOIP device and it was able to communicate with another VOIP device in the public internet but after every 1min (or less) the voice communication gets terminated. We have tried the VOIP solution with other types of NAT and there was no problem.
The first (and most ideal) solution would be to see if your VOIP supports some form of Keep Alive. You can browse the product documentation for this. If it does, turning that on should resolve the problem.
The second alternative is to go into the Extended Networking properties, go to the Port Security tab and see if there is an entry for UDP ports 2000 and 4000. If there are, you should be able to specify the kind of time-out values you want. Try it initially with a Custom Timeout, of around 5 minutes (Values are entered in seconds).