NordVPN app for managing WebRTC settings is a good tool. I subscribe to the NordVPN service and the more I get to know about, the better it seems overall. Update: NordVPN is still a good option for VPN services and privacy online. As a browser extension I have no complaints and again I from time to time run WebRTC leak checks and as far as I can tell it is not allowing any VOIP data to be exposed, although modern VOIP services are encrytpted anyway.