What is WebRTC?
WebRTC enables real-time audio, video, and peer-to-peer connections directly in the browser without plugins.
To establish connections, browsers may query STUN servers for candidate IP addresses — including LAN host addresses and public server-reflexive addresses.
Why VPN users care
Your VPN can mask the IP this page loads over, while WebRTC still gathers a different public address via STUN. That mismatch is the leak that matters.
Seeing 192.168 or another private host candidate is local-network visibility, not proof your ISP public IP leaked. Privacy browsers and VPN apps often limit ICE candidates to reduce both.
How to read host, STUN, relay, and mDNS
Host is a local interface. A 192.168, 10.x, or IPv6 ULA host address means this page can see your LAN. That is not the same as a public IP leak.
Server-reflexive (srflx) is a public address as a STUN server sees you. Compare it to Public IP on this page. A mismatch in that family is the VPN-relevant leak.
Relay (TURN) is traffic via a turn server, not your ISP address. Peer-reflexive (prflx) is learned from a peer. mDNS names end in .local: this test ignores them for the verdict because they hide the raw LAN IP, not a public leak.
Run it twice: before and after connecting
Load this test with the VPN off and note Public IP and Public WebRTC. Connect the VPN, run it again, and both public values should match the VPN exit — not your home ISP.
If Public WebRTC still shows your ISP address after connecting, the tunnel is not covering WebRTC. Enable the VPN’s WebRTC protection or limit ICE candidates in the browser, then re-test. Next, run DNS Leak Test.
IPv4 and IPv6 are compared separately
This page loads over one IP family. The automatic verdict only compares public WebRTC addresses in that family, so a dual-stack IPv6 STUN address is not treated as a leak just because the page used IPv4.
When the other family appears, we list it and ask you to compare it to the matching VPN exit if you have one. We stay on one STUN server; a second STUN would not change that rule.
How to reduce WebRTC IP exposure
Chrome and Edge no longer offer the old chrome://flags “WebRTC IP handling” toggle many guides still describe, and the WebRTC Network Limiter extension is retired. Managed browsers can set the WebRTC IP handling policy (default public interface only, or disable non-proxied UDP). Otherwise use a VPN that includes WebRTC protection.
Firefox: in about:config, media.peerconnection.ice.default_address_only and media.peerconnection.ice.no_host hide LAN host candidates. Setting media.peerconnection.enabled to false turns WebRTC off and breaks in-browser calls.
Safari: limit WebRTC in site settings where available. Prefer hiding IPs over disabling WebRTC unless you never need browser calls. Then re-run this test.