WebRTC Leak Test

WebRTC Leak Test – Check Whether Your Browser Gives Away Your Real IP Address

A webrtc leak test answers a question most VPN users never think to ask: while your VPN is happily showing a website one IP address, is your browser quietly handing it a different one? WebRTC — the technology inside your browser that powers video calls, voice chat and in-browser gaming — can reveal your real public IP address to any website that asks, even while a VPN is connected. The test above takes about ten seconds. It asks your browser to list the network addresses WebRTC can see, fetches the public IP address websites normally see, and compares the two for you.

This page is part of Speed Test UK, where every checker gives you a straight answer rather than a screen of raw numbers. Below: what a WebRTC leak is, how to run the test properly (including the two-pass method that gives a definite answer), what each result means, and the exact fix for every major browser.

What Is a WebRTC Leak?

WebRTC (Web Real-Time Communication) is built into Chrome, Edge, Firefox, Safari and Opera. It lets browsers talk directly to each other for Google Meet calls, Discord in the browser, online games and live streaming, without plugins. To set those connections up, the browser has to work out how it can be reached across the internet — including through routers and firewalls that normally hide your devices. It does this using a process called ICE, asking a helper server (a STUN server) a simple question: “When I connect from here, what address do you see?”

The answer is your public IP address — the one your broadband connection presents to the world. The problem is that this lookup happens inside the browser, and depending on how your VPN and browser are set up, WebRTC may find a route that goes around the VPN tunnel or simply report the address of your real network connection. Any website can run the same trick with a few lines of JavaScript, invisibly, in the time it takes the page to load. That is a WebRTC leak: not a hack, not malware, just a useful browser feature doing its job in a way that can quietly undo your VPN’s privacy.

Two things are worth knowing before you worry. First, a leak only matters if you use a VPN (or proxy) to hide your real address — without one, WebRTC reveals the same IP address every website already sees. Second, the local addresses WebRTC reports, such as 192.168.0.12, stay inside your home network: they identify a device on your Wi-Fi, not you on the internet, and modern browsers usually hide even those behind random .local names.

How to Run This WebRTC Leak Test

The test itself needs nothing but the button above. For a result you can act on, follow this method:

1. Decide what you are testing. If you want to know whether your VPN leaks, connect to your VPN first, in the country and city you normally use.
2. Click “Run WebRTC Leak Test”. The tool gathers ICE candidates from your browser using a public STUN server, and separately looks up your normal public IP address.
3. Read the verdict. Green means the addresses match. Amber means something needs a second look. Red means WebRTC exposed a public IP address different from the one your browsing uses.
4. Note both addresses. You will want them again after applying any fix, to confirm the leak has closed.
5. Repeat in every browser you use. WebRTC behaviour is set per browser. A leak fixed in Chrome says nothing about Firefox on the same computer.

The technology is open: the WebRTC project site explains it, and the MDN WebRTC documentation covers the browser APIs this test uses. Open your browser’s developer tools and you can watch the same lookups happen.

What Your Results Mean

The panel above shows up to three kinds of address. Here is how to read them, and what each outcome usually points to.

The key comparison is public IP versus public IP. If both agree, a website learns nothing extra from WebRTC. If they disagree while a VPN is connected, treat the extra address as exposed until you have fixed it and re-tested.

The Definite Method: Test With the VPN Off, Then On

One run tells you whether the addresses match right now; two runs tell you exactly whose address is leaking. First, disconnect your VPN completely and run the test — note the “normal public IP”, your real broadband address. Then connect the VPN, refresh this page and run it again. Your normal IP should now be the VPN’s address. If the WebRTC panel still shows that first, VPN-off address, you have confirmed a leak and identified the exact address escaping.

This before-and-after approach is also the fairest way to judge a VPN app. Some providers handle WebRTC well on their default settings; others only block leaks when a specific “leak protection” or “block WebRTC” option is switched on in their settings. If the second run still exposes your real address after every app protection is enabled, the problem is in the browser — work through the fixes below. You can cross-check the addresses any time with our What Is My IP tool.

How to Fix a WebRTC Leak

Fixes fall into two halves: settings inside your browser, and settings inside your VPN app. Do the VPN half first — it is usually a single toggle — then the browser half if the leak persists.

Check your VPN app settings first

Open your VPN app’s settings and look for options named “WebRTC leak prevention”, “Block WebRTC”, “IP leak protection” or similar, and turn them on. Also enable the kill switch: it does not stop WebRTC leaks directly, but it prevents all traffic escaping if the tunnel drops. If your VPN routes only some apps through the tunnel (split tunnelling), remember that a browser excluded from the tunnel will always show your real address in every test — that is the split tunnel working as configured, not a fault.

Firefox: the two-minute fix

Firefox is the only major browser with a built-in WebRTC off switch. Type about:config in the address bar, accept the warning, and search for media.peerconnection.enabled. Double-click it to set it to false. WebRTC is now fully off — leaks are impossible, but browser video calls (Meet, Teams in the browser) will stop working. If you need those calls, instead set media.peerconnection.ice.no_host to true: this hides your local addresses while keeping calls functional. Mozilla’s guide to the Firefox Configuration Editor explains how the about:config screen works if you have never used it.

Chrome and Edge: no off switch, so control the policy

Chrome and Edge do not let you disable WebRTC in settings. The practical fix is a small extension that controls WebRTC’s IP handling policy (search the Chrome Web Store for “WebRTC control” or “WebRTC leak prevent”), set to its strictest option — often labelled “Disable non-proxied UDP”. That forces WebRTC to use only the VPN route or nothing. Be fussy about which extension you install: a WebRTC controller needs no access to your browsing history, so avoid any that ask for it. Edge has one extra built-in option: type edge://flags, find “Anonymize local IPs exposed by WebRTC” and enable it — that masks local addresses only, so combine it with an extension or VPN protection for the public-IP side.

Safari

Safari applies mDNS masking by default and is generally the least leaky major browser for local addresses. There is no user-facing WebRTC switch on iOS, and macOS Develop-menu options change between versions — the dependable route is your VPN app’s leak protection, verified with the two-pass test above.

WebRTC Leaks vs DNS Leaks: Check Both

A WebRTC leak exposes your IP address through the browser’s calling features. A DNS leak is different: your device asks your broadband provider’s DNS servers to look up website names even though the rest of your traffic uses the VPN, revealing which sites you visit. A setup can pass one test and fail the other, and the fixes live in different places. Run our DNS Leak Test alongside this one whenever you set up a new VPN, browser or router — together they take under a minute.

Running the Test From the UK: What to Know

A few UK specifics change how you read your results. Most UK broadband connections — BT, Virgin Media, Sky, TalkTalk, EE and Plusnet among them — give you a dynamic public IP address that changes from time to time. So do not panic if last week’s address differs from today’s: what matters is whether the two addresses in a single run match each other. A changing address also means a leaked IP identifies your connection and rough area rather than you personally — worth fixing, but not a catastrophe.

Second, VPN use in the UK has jumped as age-verification checks and online-safety rules have pushed people towards them, and many users connect to appear in another country or to watch UK television abroad. Testing from abroad with a VPN set to a UK server works in reverse: your normal IP should be the UK VPN address, and any WebRTC address pointing to your real location is the leak. If your results look clean but the connection feels wrong, run a broadband speed test too — privacy and performance checks answer different questions.

Troubleshooting Odd Results

The test shows nothing at all. WebRTC may be disabled (by you, an extension, or a work/school device policy), or a strict network blocked the STUN server. That outcome is good for privacy. If browser calls also fail in this browser, one of those blocks is the reason.

Different browsers give different results. Completely normal — WebRTC settings, extensions and defaults are per browser. Fix and re-test each browser separately.

The WebRTC IP is not mine or my VPN’s. Occasionally you will see an address from your VPN provider’s wider network rather than the exact exit server you chose. If it belongs to your provider, it is not your real address escaping — confirm with the two-pass method to be sure.

IPv6 addresses appear. Some UK connections have IPv6 alongside IPv4. If your VPN only tunnels IPv4, an IPv6 result in your ISP’s range is a genuine leak route — look for IPv6 leak protection in the VPN app.

Frequently Asked Questions

Is a WebRTC leak dangerous?

It is a privacy problem rather than a security breach. Your IP address reveals your approximate location (usually town or city level) and your provider, and lets websites link your activity to your real connection despite the VPN. It does not expose passwords or files by itself, but if you pay for a VPN to keep your address private, a leak defeats the point.

Does incognito or private browsing stop WebRTC leaks?

No. Private windows change what is stored on your device afterwards; they do not change how WebRTC gathers network addresses. A VPN plus a private window can still leak in exactly the same way, so test in the browsing mode you actually use.

Why does the test show names ending in .local?

Those are mDNS hostnames. Chrome and Firefox generate random .local names to stand in for your real local IP addresses, so websites cannot see your home network layout. Seeing them is a sign the masking is working, not a fault — the tool labels them so you do not mistake them for a leak.

Will disabling WebRTC break anything?

Yes, potentially: browser-based video and voice calls (Google Meet, Microsoft Teams and Discord in the browser, some online games and live-streaming tools) rely on WebRTC. If you fully disable it, use those services in their dedicated apps instead, or choose the gentler fixes — hiding local addresses, forcing WebRTC through the VPN route — which keep calls working.

Can a website really see my IP address with WebRTC without me knowing?

Yes. The same few lines of code this test runs can run on any page, with no permission prompt and no visible sign, because WebRTC was designed to work silently in the background. That is why the only reliable defence is to test your own setup and close the gap with browser or VPN settings.

Should I test again after fixing?

Always. Apply one fix at a time, refresh this page and re-run the test, so you know which change closed the leak. Also re-test after major browser updates and whenever you change VPN provider, VPN protocol or router — settings that affect WebRTC are scattered across all four.

Run the Test, Fix the Gap, Test Again

Scroll back up, connect your VPN the way you normally use it, and run the webrtc leak test. Green means evidence — not just hope — that your browser and VPN agree about who you are. Red means a few minutes of fixes, then a ten-second re-test. For the full picture, pair this with our DNS leak test and a quick visit to Speed Test UK to check the connection itself.