Why WebRTC Can Leak Your Real IP: Causes, Risks & Fixes

Many people encounter WebRTC leaks for the first time when their proxy is already connected, and the IP detection page shows normal, but as soon as they check for WebRTC leaks, their real IP is directly exposed.

In fact, WebRTC itself is not a vulnerability; it is a communication mechanism designed for "direct connection efficiency." Its "overly real" nature has become a source of risk.

Next, let's explain in detail: why WebRTC can leak the real IP, how it is identified by browser fingerprinting, and how to truly reduce the risk of leaks.

1.What is a WebRTC Leak? It Was Originally a “Good Thing”

WebRTC stands for Web Real-Time Communication and is a real-time communication technology built into browsers.

Its original purpose is to allow browsers to make direct voice and video calls without extra plugins, with low latency and high efficiency.

For example, when you hold video conferences or voice chats on a webpage, much of the underlying work relies on WebRTC.

The problem is: WebRTC actively collects network information to enable “direct connections.”

2. The Core Reason for WebRTC Leaks: Bypassing Proxies for Direct Connection

1️⃣ WebRTC Uses the ICE Framework

When establishing a connection, WebRTC uses a mechanism called ICE (Interactive Connectivity Establishment).

ICE tries multiple methods to establish the most stable connection, including:

•  Local LAN IP

•  Public IP

•  Relay server IP (TURN)

To improve success rates, it actively probes your real network exit information.

2️⃣ Proxy ≠ Default WebRTC Channel

The issue is that browser proxies (HTTP/SOCKS) and IP tunneling tools are not necessarily used by WebRTC.

The result is: page script calls WebRTC → WebRTC directly obtains the real IP → proxy is effectively useless.

This is what is called a WebRTC real IP leak.

3. How WebRTC Leaks Are Detected

The logic for detecting WebRTC leaks is actually quite simple:

•  Page calls WebRTC API via JS

•  Retrieve ICE Candidates

•  Parse the IP addresses contained

•  Compare current exit IP with proxy IP

If any of the following occur, a WebRTC leak is confirmed:

•  Local IPv4

•  Internal network IP

•  Non-proxy public IP

4. How to Perform WebRTC Leak Detection? Don’t Rely on a Single Check

Many people check WebRTC on only one page, which is not enough. A more reliable method is comprehensive detection:

•  WebRTC leak detection

•  DNS leak detection

•  Canvas / WebGL

•  Fonts, timezone, language

•  IP correlation analysis

Combined, these make up a complete browser fingerprint detection system.

Tools like ToDetect have the advantage of not only detecting WebRTC but also evaluating risks from fingerprint consistency.

This is closer to real-world risk control logic and is much more reliable than “single-point IP detection.”

5. How to Reduce Risks Caused by WebRTC Leaks

1️⃣ Disable WebRTC Directly (for Low-Demand Scenarios)

Firefox: Set media.peerconnection.enabled to false.

Chrome / Edge: Can only be restricted via parameters, extensions, or policies.

This has the following effects:

•  Pages cannot obtain ICE information via WebRTC

•  Local IP and real public IP are no longer exposed

But the drawbacks are clear:

•  Some websites’ video or voice features may malfunction

•  Easily detected by risk control systems as “non-standard environment”

👉 Conclusion: Suitable for general users, not suitable for high-demand environments.

2️⃣ Make WebRTC Use the Correct Exit Instead of Simply Disabling It

Let WebRTC use the proxy IP instead of the real IP; this is what many fingerprinted browsers and professional environments do.

Core approach:

•  Keep only the proxy IP type in WebRTC

•  Prevent exposure of local/internal IPs

•  Ensure ICE Candidate results match the proxy exit

This way, during WebRTC leak detection:

•  Pages can still obtain an IP

•  But it is a “valid proxy IP”

•  No real network fingerprint conflicts occur

This is crucial for browser fingerprint consistency.

3️⃣ Don’t Ignore IPv6, a Major Source of WebRTC Leaks

This is a common pitfall rarely explained clearly. Why IPv6 is particularly easy to leak:

•  Many proxies only handle IPv4

•  WebRTC prefers IPv6

•  System defaults to IPv6, but users are unaware

The result is:

•  IPv4 seems “clean”

•  WebRTC directly exposes the real IPv6

On many WebRTC leak detection pages, it is IPv6 that truly exposes identity.

👉 Risk reduction approach:

•  Disable IPv6 at the system level

•  Disable IPv6 WebRTC Candidates at the browser level

•  Use a proxy solution that isolates IPv6

4️⃣ Proxy Must Support WebRTC; Otherwise, It’s Useless

Many think: “I use a high-anonymity proxy, so WebRTC leaks won’t happen.”

In reality, these are two separate issues. Proxy safety depends on:

•  Whether it supports UDP / WebRTC traffic

•  Whether it can handle WebRTC connection requests

•  Whether the exit IP matches the browser fingerprint

If the proxy does not support WebRTC routing, no matter how the browser is configured, it’s just “covering your ears while stealing a bell.”

5️⃣ Combine with browser fingerprint detection, don’t focus only on WebRTC

WebRTC leaks are never an “isolated problem.” Real-world risk systems usually make comprehensive assessments:

•  WebRTC IP

•  HTTP request IP

•  DNS resolution results

•  Timezone, language, system parameters

•  Canvas / WebGL fingerprint

Therefore, the correct approach is: consider WebRTC as part of a complete browser fingerprint detection system.

Conclusion

Ultimately, WebRTC leaks are not vulnerabilities; it simply does too much “real work” to improve efficiency.

The real issue is that when we pursue anonymity, isolation, and multi-environments, we often overlook that it still quietly exposes information in the background.

If you care about privacy, account security, and environment isolation, then WebRTC leak detection + browser fingerprint detection must be part of your routine checks.