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What is WebRTC?

WebRTC (Web Real-Time Communication) is a technology that enables real-time communication between browsers without the need for plugins or third-party applications. Its application scenarios are very broad:

  • Audio and Video Calls: Directly initiate video or voice calls in the browser, widely used in remote work, online meetings, and telemedicine.

  • File Sharing: Directly transfer files between browsers without relying on email or other transfer tools.

  • Real-time Chat: Supports instant messaging with text, voice, and video.

  • Online Collaboration: Features like screen sharing, whiteboard drawing, and collaborative editing all rely on WebRTC.

  • Web-based Games: The foundation for implementing multiplayer games and voice chat features.

  • Remote Desktop: Remotely access and control other computers.

  • Live Streaming: Supports low-latency video streaming and playback.

In addition to Facebook Messenger, WhatsApp, Discord, Google Meet, and Zoom, a large number of communication platforms and services use WebRTC technology.

Why does WebRTC leak IP addresses?

WebRTC is designed to allow browsers to exchange audio and video data directly in most cases, without relying on an intermediary media server. To achieve this peer-to-peer connection, the browser must know its public IP address—which creates a risk of privacy leaks.

What is NAT?

When your device connects to the internet, it is assigned a private IP address that is only valid within the local network. To communicate with other devices on the internet, this private IP needs to be mapped to a globally unique public IP. This process is called Network Address Translation (NAT).

To use an analogy: your home is like a small village. Everyone has their own house number (private IP), but the entire village shares the same postal code (public IP). When you send a letter to someone outside the village, you must write this postal code so the mail carrier knows where to deliver it. NAT is like the village post office, responsible for sending data packets from inside the village (local network) to the outside world (internet). This way, multiple devices in your home can access the internet through the same public IP.

How does WebRTC get your real IP?

To establish a peer-to-peer connection between browsers, WebRTC needs to obtain the user's real IP address. It accomplishes this using the ICE (Interactive Connectivity Establishment) framework, which includes two core components:

STUN Server: Used to obtain the user's public IP address and port. Since most users are behind a NAT, their private IP cannot be used directly for internet communication. A STUN server helps the browser "discover" its own public IP.

TURN Server: When certain network configurations prevent STUN from directly obtaining a public IP, the browser can use a TURN server as a relay to establish a connection. However, TURN introduces additional communication latency, so STUN is more commonly used.

In simple terms: WebRTC obtains the user's real IP address through STUN or TURN servers to establish a peer-to-peer connection. While this is a normal part of WebRTC communication, it raises privacy and security concerns—your real IP could be leaked as a result.

How to detect a WebRTC leak?

You can use tools like realfp to check if WebRTC is leaking your real IP. When you visit the detection page while connected to a VPN, the IP address section will show both the proxy IP and the real IP obtained by WebRTC. It's important to note that some VPN or proxy services cannot effectively prevent WebRTC leaks.

How to prevent WebRTC IP leaks?

Here are several common prevention methods:

  1. Completely disable WebRTC: Most modern browsers allow you to disable or restrict WebRTC functionality in their settings or privacy preferences. This is the simplest and most direct method.

  2. Use browser extensions: Some specially designed privacy protection extensions can effectively prevent WebRTC leaks, such as WebRTC Network Limiter, WebRTC Control, and WebRTC Leak Prevent.

  3. Choose a more reliable proxy or VPN: Not all proxies or VPNs can block WebRTC leaks. After choosing a provider, you should use a detection tool to verify its effectiveness.

  4. Use an anti-detection browser (Recommended): Almost all anti-detection browsers on the market today support modifying WebRTC behavior, preventing third-party websites from obtaining your real IP. Even if a website can get an IP, it will be the proxy IP, not your real one. Sometimes, "replacing" is more effective than "disabling"—it makes websites see you as a regular user, not someone intentionally hiding their identity.