WebRTC Leak Test: Why Your Proxy Extension Still Exposes Your Real IP

A WebRTC leak happens when a browser reveals your device's real IP address through the WebRTC channel even though a proxy is already masking your IP at the HTTP layer — the most common cause is running the proxy as a browser extension instead of attaching it directly to an isolated browser profile.

A WebRTC leak means your browser is quietly handing over your real IP address through a separate connection channel, completely bypassing whatever proxy you have turned on. The result is an account that looks like it is browsing from the US on the surface, while the platform's anti-fraud system still sees your real Vietnam IP underneath — more than enough to flag the session. This article breaks down why the leak happens even when the proxy itself works fine, how to test for it with a free browser fingerprint scanner, and how to fix it by attaching the proxy directly to a profile in GPM Login instead of using an extension.

What Is a WebRTC Leak, and Why Does It Make a Proxy Pointless?

A WebRTC leak is when the browser's WebRTC API discloses a device's real IP address to a website, regardless of whatever proxy or VPN is active at the network layer. WebRTC exists so two browsers can connect directly, peer-to-peer, for things like video calls or file sharing, so it needs to know the real IP to find the shortest possible route — and many browsers let this happen quietly by default.

When a page runs a WebRTC check — common on the anti-fraud systems used by social platforms, marketplaces and banks — the browser returns a list of network addresses called ICE candidates, which usually include your real public IP even while you are browsing through a proxy. If that address does not match the IP the proxy is showing at the HTTP layer, the platform sees two mismatched network signals in the same session, a textbook sign of an account trying to hide its real location.

According to GPM Login's fingerprint knowledge base on WebRTC IP, this is one of the signals platforms routinely cross-check against the proxy IP, alongside timezone, canvas fingerprint and user agent.

Why Does a Chrome Proxy Extension Still Expose Your Real IP?

Because a proxy extension only intercepts a browser's regular HTTP/HTTPS traffic — it has no control over the WebRTC channel, so when a page asks for an IP through WebRTC, the browser still answers with the device's real network address.

A real test makes this obvious. On a plain Chrome browser with no proxy, a fingerprint scanner returned green results for Browser, Hardware and Network; only Software was flagged, because the machine was being controlled through a remote desktop session, unrelated to any proxy. After installing a proxy extension and switching it to a US IP, the page's outward-facing IP changed from Vietnam to the US — which looks fine at a glance. But a separate WebRTC test page still returned the machine's original Vietnam IP as the public IP over WebRTC, meaning the same browser session was showing two mismatched network addresses at once. Back in the scanner, Network was immediately flagged as abnormal for exposing the real IP through WebRTC.

In other words, switching proxies does not automatically mean your IP is hidden. If only the surface-level address changes while WebRTC is left untouched, the account still carries a real network signal that is more than enough for an anti-fraud system to cross-check and flag.

How Do You Test Whether Your Browser Is Leaking IP Through WebRTC?

The fastest way is to use a browser fingerprint scanner (tools like BrowserScan work well) to compare the IP shown at the HTTP layer against the IP read through WebRTC in the same session — if the two differ, the browser is leaking.

• Open the browser that is running your proxy or VPN and visit any browser fingerprint scanning site.

• Note the “Public IP” the page shows — this is normally the IP your proxy is assigning you.

• Look for a WebRTC IP / WebRTC leak test section on the same page, or open a dedicated WebRTC test page.

• Compare the public IP read through WebRTC with the one from the step above — if they differ, especially across countries, the browser is leaking your real IP.

• Check the scanner's overall result, usually broken down into Browser, Hardware, Software and Network — Network will be flagged if there is a leak.

Repeat this test whenever you change how a proxy is attached, or switch devices, since a WebRTC leak is silent — nothing in the page itself warns you it is happening.

Proxy Extension vs. Profile-Level Proxy: What Is the Real Difference?

The core difference is scope: a proxy extension only reroutes HTTP traffic at the browser level, while a proxy attached directly to a profile — as in GPM Login — is synced across that profile's entire network layer, including WebRTC, timezone and language.

Proxy via extension: HTTP traffic changes IP, but WebRTC still routes around it and leaks the real address.

How to Fix a WebRTC Leak With GPM Login

The fix is to create a dedicated profile in GPM Login, attach the same proxy you were already using directly to that profile instead of through an extension, then launch the profile so the browser can sync WebRTC, timezone and language to the proxy.

• Open GPM Login and create a new profile (Add New), or reuse an existing one for the account you need.

• In the profile's proxy settings, enter the exact proxy you were using as IP:Port or IP:Port:Username:Password — GPM Login supports HTTP, HTTPS, SOCKS4 and SOCKS5, so there is no need to switch proxies.

• Run Check Live to confirm the proxy is still active (Live) before launching the profile.

• Launch the profile — GPM Login automatically matches Timezone and Language to the proxy's IP, and applies the recommended WebRTC handling mode so WebRTC returns the proxy's IP instead of the real one.

• Go back to the fingerprint scanner and re-check: Browser, Software, Hardware and Network should all come back green this time.

• Open a dedicated WebRTC test page as a final check: the public IP read through WebRTC should now match the proxy IP shown elsewhere.

Proxy attached directly to the profile: HTTP and WebRTC now return the same IP, with no mismatch.

The full before-and-after test, including the scan results, is walked through step by step in the video below. Watch the walkthrough: https://www.youtube.com/watch?v=_g8wx0mG-zs

For the exact steps, see the official guide to creating a profile and the guide to adding and checking proxies in GPM Login's documentation.

Why Does the Full Scan Result Matter More Than Just Changing Your IP?

Because platforms do not look at a single displayed IP address — they cross-check dozens of signals at once, including IP, WebRTC, timezone, canvas and user agent. A single mismatched signal is often enough for an anti-fraud system to flag the whole session.

In practice, after running hundreds of profiles across multi-account projects, most of the “unexplained” account restrictions our technical team has seen trace back to one small mismatch — a WebRTC leak, a timezone that does not match the IP, or a system font that does not match the declared operating system — far more often than to the proxy's own quality.

To be clear: no antidetect tool can guarantee 100% that an account will never be restricted. The realistic goal is to remove the easy-to-detect mismatches, like a WebRTC leak, and bring the risk down as low as it can reasonably go.

FAQ About WebRTC IP Leaks

Is a WebRTC leak the proxy's fault?

Not really. The proxy itself still works correctly at the HTTP layer; the issue is that WebRTC is a separate channel that a regular proxy extension cannot control. The fix is not switching to a “better” proxy — it is controlling WebRTC at the right layer, the browser profile.

Is disabling WebRTC entirely the best fix?

Disabling WebRTC completely can break features that need a direct connection, such as video calls or some identity-verification steps. A safer approach is a recommended mode where WebRTC still works but returns the proxy's IP instead of being switched off outright.

Do I need to switch proxies after moving to profile-level attachment?

No — you only change how the proxy is attached, from a browser extension to a direct connection on an antidetect profile. The same proxy keeps working; the difference is that the profile's entire network layer is now synced to it.

How do I know if a fingerprint scanner is trustworthy?

Favor tools that break results down by layer — public IP, WebRTC IP, canvas, WebGL, timezone — rather than a single vague score, so you can cross-check each signal the way this article does.

What proxy types does GPM Login support?

GPM Login supports HTTP, HTTPS, SOCKS4 and SOCKS5, lets you add them in bulk as IP:Port or IP:Port:Username:Password, and includes a Check Live feature to filter out dead proxies before attaching them to a profile.

Conclusion

A WebRTC leak is a quiet failure, but an easy one to fix once you know where it comes from: the proxy is attached at the wrong layer. Moving from a browser extension to a proxy attached directly to a dedicated profile, as in GPM Login, keeps every network signal — visible IP, WebRTC, timezone — in sync, instead of only changing the surface-level address. Make it a habit to re-test with a fingerprint scanner after every proxy change or device switch.