Passive test (nothing leaves your device)
Gathers the local candidates your browser would hand to any site, using no external server.
Full leak test (uses this site's own STUN server)
This asks your browser to discover its public address over WebRTC via our own STUN server, so the only thing your IP is shared with is this site. We compare it to the IP your normal traffic uses. If you are on a VPN and these differ, WebRTC is leaking around it.
What leaves your browser
The passive test sends nothing; it only reads the candidates your browser generates locally. The full test is opt-in: when you press the button, your browser sends STUN requests to our own server (never a third party like Google), which reflects back the public IP it saw. We compare that to your normal IP and store neither. Verify in the source.
Stop the leak
Use a VPN that blocks WebRTC leaks
Good VPN apps route or block WebRTC so it cannot reveal your real IP. Re-run this test after connecting to confirm.
Disable WebRTC or install a leak-blocker
In Firefox set media.peerconnection.enabled to false in about:config. On Chrome, use an extension like uBlock Origin's "Prevent WebRTC from leaking local IP" setting.
Prefer browsers that mask host candidates
Modern browsers hide local IPs behind mDNS (.local) by default, which is why the passive test often shows no real address. That is the leak being blocked, working as intended.
These are unpaid recommendations chosen on merit. If that ever changes, this line will say so.