WebRTC leak test
WebRTC lets the browser connect directly for calls and file sharing. To do that it asks a server which address it is seen from, and behind a badly set up VPN that address can be your real one.
Checking your browser…
How the WebRTC test works
WebRTC lets two browsers connect directly, for video calls or file transfers. To find a route, the browser sends a request to a STUN server, which answers with the public address it sees. A VPN that does not carry this traffic lets it go out through your normal connection, and then a site that runs the same request learns your real address.
This page sends that request to our own STUN server and compares the answer with the address the page was loaded from. It also looks at the local candidate: current browsers hide the address of your device inside your network behind an mDNS name ending in .local.
How to read the result
- Public address in WebRTC: the address our STUN server saw. It should be the same as the page address.
- Local address: "hidden (mDNS)" is what you want. A visible local address does not reveal your location, but it makes your browser easier to recognise.
- WebRTC is off: the browser or an extension blocks it, so nothing can leak, and calls in the browser will not work.
- iCloud Private Relay: Apple carries this traffic too, and an address of another relay exit is not a leak.
Further reading
- Is my VPN working: all the checks together
- WebRTC leak: what it is and how to check
- DNS leak: what it is and why it matters with a VPN
- My IP address: what websites learn from it
- My IP and anonymity check
Frequently asked questions
- How do I stop a WebRTC leak?
- Turn on the WebRTC leak protection in your VPN app if it has one, or use a browser setting or extension that limits WebRTC to the VPN connection. Then run this test again.
- Does turning WebRTC off break anything?
- Calls and screen sharing in the browser (Google Meet, Discord and others) stop working, and a few sites notice that WebRTC is missing.
- Is it a leak if WebRTC shows an IPv6 address?
- We only compare addresses of the same type, IPv4 with IPv4 and IPv6 with IPv6, so a different type alone is not reported as a leak.
- Is anything stored?
- No. The addresses are compared for this check and forgotten; only daily sums are counted, without the checks themselves.