What is WebRTC?

WebRTC lets a browser make voice and video calls without installing an app, as in Google Meet or WhatsApp Web. To do that, the browser asks a STUN server “what is my public address from outside?” so that both sides of a call can connect directly.

Why your real IP shows despite a VPN

That STUN question usually goes over UDP, and sometimes out of a network interface other than the VPN’s. If the VPN does not send all traffic through its tunnel, or only routes the browser through a proxy, the STUN answer shows your own internet address, and any site can read it with a few lines of code.

CheckNet does exactly that on the “My device” page: it asks Cloudflare’s STUN server (stun.cloudflare.com) for your public address and compares it with the IP sites see over HTTP. If another address shows up, it shows that address and its network owner. If the other address belongs to the same provider, it is probably your other IP version (IPv4 or IPv6) and is not counted as a leak.

Stop the leak

1. Start with your VPN app’s settings. Turn on the option called something like “leak protection” or “block connections without VPN” (a kill switch), and make sure the VPN sends all traffic through the tunnel, not just the browser.
2. In Firefox: open about:config in the address bar, accept the warning, search for media.peerconnection.enabled and double-click it to set it to false. Setting it back to true undoes this.
3. In Chrome and Edge: there is no built-in switch to turn WebRTC off. Google’s own “WebRTC Network Limiter” extension in the Chrome Web Store limits WebRTC to the same route the browser uses for web traffic. After installing it, look at its options too.
4. In Safari, on iPhone and iPad: there is no simple setting for this. Rely on your VPN app’s leak protection and check the result again.
5. Close and reopen the browser, turn the VPN on, and reload the “My device” page.

Turning WebRTC off breaks voice and video calls inside the browser. If you use Meet or a similar service in the browser, prefer the extension or the VPN’s leak protection over switching it off completely.

The local network address row

Sometimes WebRTC shows the device’s address inside your home network, such as one starting with 192.168. It cannot be reached from the internet and does not reveal who you are, but sites can use it to recognise your device again. Most of the fixes above close this too; recent browsers usually show a temporary name ending in .local instead of this address.

Check again with CheckNet

With the VPN on, open the “My device” page. If the WebRTC row says it does not reveal another IP, or that the browser has no WebRTC or has it turned off, nothing leaks this way. If you still see your own internet address, try another method from the list above.