WebRTC
WebRTC is the browser's built-in real-time audio/video feature behind web video meetings and voice calls. It reports your IP to the outside over UDP.
Think of it like this
Like slipping a reply card with your home address into a parcel: the parcel went through a shopper, but the reply card comes straight back to your door.
In this setup
If Clash Verge only has "System Proxy" on, the browser's WebRTC bypasses the proxy and shows websites your real IP. The right fix is turning on "Tun Mode" so UDP also goes through the server — WebRTC keeps working. Do not use extensions that disable WebRTC instead; that breaks video and voice on web pages.
Common misconceptions
- "No IP detected means it is fixed": that usually means WebRTC has been disabled, not fixed.
- "Some Chinese test sites still show a Chinese IP, so it is not fixed": if that site uses a Chinese STUN server, Rule mode connects to it directly — that is expected.
Try it: Check for WebRTC leaks
Related: System proxy vs TUN, TCP and UDP, DNS leak