WebRTC IP Leak Test

What is a WebRTC leak, and how can you prevent one?

WebRTC (Web Real-Time Communication) enables real-time audio, video, and peer-to-peer data in browsers. A WebRTC leak occurs when ICE candidates expose a local or public address that differs from the IP used for normal HTTP or HTTPS traffic, potentially revealing a path outside your intended VPN or proxy.

How WebRTC leaks happen

1. When a browser creates a peer-to-peer connection, it gathers ICE candidates through STUN or TURN services.
2. host represents a local-device or LAN candidate; srflx is the public mapped address observed by STUN; and relay is an address provided by a TURN relay.
3. If a host or srflx candidate differs from your current HTTP exit, the real-time WebRTC path may not be fully using your intended VPN or proxy.

A public candidate alone does not prove a leak. Compare it with the current HTTP exit. A different address, a clearly inconsistent location, or an unexpected ISP address is what warrants closer review.

Reducing WebRTC leak risk in Chrome

First, confirm that your VPN or proxy handles UDP, IPv6, and WebRTC traffic. Modern Chrome versions generally use mDNS to hide local addresses. If your proxy cannot control WebRTC paths, or you want to restrict candidate exposure further, consider one of the following extensions. Avoid installing multiple extensions that do the same job:

• WebRTC Network LimiterProvided by Google to limit the network routes WebRTC can use.
• WebRTC Leak PreventOffers manual controls for how WebRTC handles IP addresses.

Run this test again after installing an extension. These tools can affect browser video meetings, voice calls, screen sharing, and peer-to-peer transfers. If those features stop working, review the extension settings instead of stacking more extensions.

Preventing WebRTC leaks in Firefox

Open about:config, find media.peerconnection.enabled, and set it to false to disable WebRTC completely. This also disables browser video meetings, voice calls, screen sharing, and some peer-to-peer features. Set it back to true when you need those features, and use a trusted VPN with an appropriate WebRTC and UDP policy to reduce leak risk.