WebRTC is a browser feature that allows real-time peer to peer communication. This is great for things like audio/video communication. However, this also presents an exploit where your public IP address can be captured even if you’re using a VPN connection. If you are not planning on using voice/video over the web browser, you can disable WebRTC so that never presents an issue.
To disable WebRTC in the chrome browser, download one of the following addons: WebRTC Leak Prevent, WebRTC Control, or Easy WebRTC Block.
Open Firefox and type about:config in the address bar. Then, filter the option media.peerconnection.enabled and set it to false.