IP Leak Test: What Is an IP Leak and How to Fix It in 2026
TL;DR:
- The Core Problem: An IP leak happens when your real network path or address is exposed to websites even while a VPN, proxy or isolated browser profile is running. In multi-accounting, dropshipping and arbitrage it is one of the most common causes of account linking and sudden security challenges.
- The Main Culprits: A leak is not one bug. The four common classes live on different layers of the network stack: WebRTC ICE/STUN candidates, DNS resolver paths, IPv6 routes that stay outside an IPv4-only tunnel, and direct fallbacks after a proxy or tunnel failure.
- How to Check: Never guess your security. Run an IP leak test (browserleaks.com, iphey.com or Gologin’s built-in checker) and compare independent paths HTTP egress, WebRTC, DNS and IPv6 instead of trusting a single “What is my IP” result.
IP Leak Test: Check Your Real IP Right Now
Run this IP leak test in the exact profile and proxy configuration you use for
your accounts. It reports your public IP and its ASN, the WebRTC server-reflexive
candidate, the DNS resolver answering your queries, your IPv6 status and your
browser time zone, five values a detection stack cross-references to decide
whether your identity is consistent.
You fail this test if any row disagrees with the others: a WebRTC
candidate showing your real ISP address, a DNS resolver belonging to your home
provider, a live IPv6 address your tunnel never captured, or a time zone that does
not match the proxy country. A single mismatch is enough platforms do not need
all five.
IP Leak Test: Check Your Real IP Right Now
Run this IP leak test in the exact profile and proxy configuration you use for your accounts. It reports your public IP and its ASN, the WebRTC server-reflexive candidate, the DNS resolver answering your queries, your IPv6 status and your browser time zone five values a detection stack cross-references to decide whether your identity is consistent.
Read the rows against each other, not in isolation. A WebRTC candidate showing your real ISP address, a DNS resolver belonging to your home provider, a live IPv6 address your tunnel never captured, or a time zone that does not match the proxy country, each of these is a consistency failure worth fixing before you log in. A single mismatch is a strong detection signal rather than an automatic ban: thresholds are proprietary, and every platform weighs the signal alongside account history, IP reputation and behaviour.
You’ve done everything right. You set up a fresh proxy, paid for a premium VPN, spun up a new browser profile. Then your ad account dies overnight. Your dropshipping store gets flagged. Your three carefully separated arbitrage accounts merge into one banned mess.
Welcome to the most underestimated problem in multi-accounting: the IP leak.
An IP leak occurs when your browser or device uses a network path that exposes an address or a resolver outside the proxy, VPN or isolated profile boundary you intended. It can appear in ordinary HTTP traffic, in WebRTC ICE/STUN, in DNS resolution, over IPv6, or as a direct fallback after a proxy or tunnel failure. Because those paths are independent, a single leaked packet is enough for a platform’s detection stack to link your “new” identity back to a banned one.
This guide breaks down exactly how IP leaks happen, how to test for them, and how serious operators close every gap in 2026.
The Mechanics: What Factors Influence an IP Leak?
There isn’t one type of IP leak. There are at least four common ones, and each operates on a different layer of the network stack. Understanding the difference is the line between feeling secure and actually being secure.
WebRTC Leaks (The Classic “Browser Leak IP” Cause)
WebRTC Web Real-Time Communication is a protocol built into every modern browser. It powers video calls, voice chats, and peer-to-peer file transfers without plugins.
To make peer connections work, WebRTC uses ICE (Interactive Connectivity Establishment) to gather candidate network paths, and those candidates are not all the same thing. Host candidates come from your local network interfaces. A server-reflexive candidate is learned through a STUN server and reflects the public source address seen on the route your traffic actually took. A relay candidate is allocated on a TURN server, so the address advertised to the peer is the relay’s, not yours. Conflating the three is what makes most WebRTC advice wrong.
Here’s why this matters: a browser-layer proxy does not automatically cover WebRTC UDP. A Chrome extension routes HTTP and HTTPS requests, but if direct Internet access is still available, the STUN path can expose an ISP-facing address the extension never touched your proxy says Lisbon while a JavaScript call to RTCPeerConnection quietly surfaces a candidate from Manchester. RFC 8828 describes exactly this: a classical application proxy can be bypassed, and a split-tunnel VPN can expose both the VPN address and the ISP address at once. A correctly configured full-tunnel VPN that captures the relevant IPv4 and IPv6 routes, however, can carry WebRTC traffic normally.
Modern Chromium also replaces many private host-candidate addresses with temporary mDNS hostnames, which reduces local-address disclosure. It does not fix a public STUN request that left through the wrong interface the two problems are separate, and only one of them is solved for you by default.
In practice, WebRTC is the vector worth checking first, simply because it is the easiest to miss: nothing in the browser UI tells you a candidate was gathered. That is an operational recommendation, not a claim about which leak is statistically most frequent.
DNS Leaks
When you type a URL, your device has to translate that name into an IP address. That translation goes to a DNS resolver.
A DNS leak happens when name resolution follows a resolver path outside the boundary you intended your ISP’s resolver, a browser-managed DNS-over-HTTPS service, an application-specific resolver, or a different path for IPv4 and IPv6. The proxied connection itself still works, but the resolver and any on-path observer can now learn the domain names you look up. That is not the same as seeing every full URL you visit, and encrypted DNS changes who can observe the query at all, but it is still a record of where you go.
Leak-test sites do not read your resolver out of a JavaScript API; no such standard API exists. Instead, they trigger lookups for unique domain names they control and then observe which recursive resolvers query their authoritative DNS infrastructure. BrowserLeaks, for example, resolves 50 randomly generated hostnames split between IPv4-only and IPv6-only names, and reports the resolvers it saw on the server side.
Interpret the result carefully. A resolver in a different city or ASN from your exit IP is not automatic proof of failure: public resolvers, anycast infrastructure, enterprise DNS, VPN-operated resolvers and remote proxy-side resolution all produce legitimate differences. The strong signal is a resolver that belongs to your own ISP, or a path that plainly contradicts the architecture you configured.
IPv6 Leaks
The internet is in the middle of a slow, messy migration from IPv4 to IPv6, and the leak here is a dual-stack routing problem rather than a property of IPv6 itself. If your VPN or proxy protects only IPv4 while your host still has a usable native IPv6 route common on home fibre and modern mobile networks traffic to IPv6-enabled destinations can leave entirely outside the tunnel. RFC 7359 documents this exact failure mode.
Whether that happens depends on your specific product and profile, not on the market as a whole. Plenty of 2026 VPNs and proxies handle IPv6; the question to answer for your own setup is whether IPv6 is tunnelled, blocked, or simply ignored.
Google, Facebook and Cloudflare are all fully dual-stack, which is where the second half of the problem comes in. Modern connection logic follows Happy Eyeballs-style racing: the client attempts IPv6 and IPv4 concurrently and takes whichever path establishes efficiently. It does not blindly “prefer” IPv6, but if IPv6 is available and fast, it can be selected, and that is enough to expose an unprotected route while your IPv4 proxy sits there looking perfectly configured.
This is why a “working” VPN sometimes mysteriously fails on certain sites and not others. The IPv6 packet went straight out the front door.
HTTP Referer and JavaScript Fingerprinting
Even without a hard leak, fingerprinting scripts collect dozens of small data points: time zone, language headers, canvas rendering, font lists, hardware concurrency, audio API output. None of these are an IP. But cross-referenced with a leaked DNS lookup or an exposed IPv6 packet, they’re enough to map your true origin with high confidence.
This is the layer where simple proxy setups die. The IP looks right. The fingerprint screams “same user as the one banned yesterday.”
How to Perform an IP Leak Test
You can’t fix what you don’t measure. Running a proper IP leak test takes about five minutes and exposes weaknesses that no marketing page will admit to.
Step 1. Turn off your VPN, proxy and anti-detect browser, then run the test above. Note the public IP, DNS resolver and time zone it reports this is your real baseline.
Step 2. Enable your anonymization stack: connect the proxy, launch the anti-detect profile or activate the VPN.
Step 3. Re-run the test in that profile. Compare every row against the baseline you recorded in Step 1. Nothing from Step 1 should still be visible.
Step 4. Read the results in order: WebRTC first, because it is the easiest to overlook; then the DNS resolver’s ASN; then IPv6; then time zone and locale. Test IPv6 on a network that actually provides it an IPv6 test on an IPv4-only connection proves nothing.
Step 5. Investigate anything that disagrees: a WebRTC section exposing your real public or local IP, DNS servers belonging to your ISP rather than the proxy provider, an IPv6 address matching your home connection, or a time zone that doesn’t line up with your proxy’s country. Remember that public and anycast resolvers can legitimately sit in another city, so check the ASN and the architecture, not just the flag on the map.
What a clean run proves is network-path consistency: every measured path leaves through the same egress. That is not the same as complete anonymity fingerprints, account state, authentication history and behaviour are separate identity surfaces entirely.
💡 Expert Insight
Timothy Christian Sumali
Cybersecurity Consultant & CTO at Encripti | Technical Content Reviewer
How to Prevent Your IP from Leaking
Standard prevention methods exist, and they help to a point.
- Disabling WebRTC in your browser flags or via an extension closes the most visible leak. The catch: many modern sites — video conferencing tools, customer support chats, even some checkout flows break without it. You trade leak protection for functional websites.
- Network-level kill switches drop traffic the moment your VPN connection fails, which covers the disconnect case. How much more they cover depends on how they are built: a basic kill switch only reacts to tunnel loss, while a firewall-based policy can also block direct DNS, WebRTC UDP and other native-interface egress while the tunnel is up.
- Custom DNS configuration pointing your system at Cloudflare’s 1.1.1.1 or a proxy-provided resolver closes the DNS path but doesn’t touch WebRTC or IPv6.
Each of these is a patch. None of them creates a complete, isolated identity.
Fail-closed networking: the property that actually matters
The useful question is not “is a proxy enabled?” but “what happens when it stops working?” Fail closed means that losing the approved network path produces a connection error instead of a silent switch back to the host’s ordinary Internet route.
That has to hold across every socket class that matters — HTTP/HTTPS, WebSockets, DNS, WebRTC/UDP, IPv4 and IPv6, because the weakest one defines the boundary:
| Control | Required behaviour | Correct failure state |
|---|---|---|
| Proxy resolution | No DIRECT route or bypass unless explicitly intended | The request fails when the proxy is unavailable |
| WebRTC | Block non-proxied UDP; use supported proxied or relayed transports | No direct STUN or media path on the physical interface |
| DNS | Remote or protected resolver path; browser DoH and local fallback under control | Resolution fails rather than quietly using ISP DNS |
| IPv4 / IPv6 | Equivalent tunnel, proxy or block policy for both families | No native-family fallback outside the profile boundary |
| Network change | Re-evaluate routes and sockets after an interface or tunnel change | New sockets cannot migrate to an unapproved egress |
Chromium makes this concrete: an explicit proxy configuration without a DIRECT fallback fails a request with ERR_PROXY_CONNECTION_FAILED when the proxy is unreachable, while a PAC file that includes DIRECT, or a non-mandatory PAC that fails can silently fall back to direct connectivity. Chromium also exposes a separate WebRTC policy, disable_non_proxied_udp, whose documented purpose is to keep WebRTC on a transport the proxy can actually carry. In other words, “proxy enabled” is not the same as “direct networking impossible”, and WebRTC needs its own policy on top.
That’s where the toolset has to change.
How to avoid IP leaks with Gologin
Gologin isn’t a VPN or a proxy extension. It’s an anti-detect browser designed to address the leak vectors above inside one isolated profile, at the native level rather than through page-level rewriting.
Each profile gets its own spoofed canvas, WebGL and audio fingerprints the GPU-rendered signatures platforms now use to identify hardware. WebRTC is handled through the profile’s Advanced Profile Settings: the “Based on IP” mode aligns WebRTC behaviour with the profile’s proxy IP instead of disabling the API, so video calls and modern sites keep working, and an “Off” mode is available when you want WebRTC gone entirely. The profile proxy determines the IP websites see, and traffic from integrated proxies is routed through the proxy assigned to that profile.
DNS behaviour depends on the proxy type, and it’s worth setting up deliberately rather than assuming. Gologin’s Custom DNS option works with SOCKS proxies, VPN connections and direct connections, but not with HTTP or HTTPS proxies, so if you need a specific resolver pinned to a profile, choose the proxy type accordingly and verify the result with a DNS leak test before you rely on it.
The outcome you’re aiming for is what platforms actually look for: an internally consistent identity. A Vienna time zone, a Vienna IP, a Vienna DNS resolver, a hardware fingerprint that doesn’t match any previously flagged profile, and no WebRTC candidate pointing at your real machine in Birmingham.
For dropshippers running region-locked Shopify stores, arbitrageurs juggling marketplace accounts, or automation engineers running hundreds of profiles in parallel, that consistency is the difference between scaling and starting over.
Frequently Asked Questions
What causes an IP leak?
The most common causes are WebRTC candidate gathering that escapes a browser-layer proxy, DNS resolution that follows a path outside your tunnel, IPv6 traffic on a connection where only IPv4 is protected, and direct fallback after a proxy or tunnel failure. Each exposes a different piece of your real network path, often without any warning from your VPN or proxy software.
Can a browser leak my IP address if I use a VPN?
It depends on how the VPN is routed. WebRTC can expose an ISP-facing address when it bypasses a browser-layer proxy or extension, and when a split-tunnel configuration leaves part of your traffic on the physical interface RFC 8828 describes both cases. A correctly configured full-tunnel VPN that captures the relevant IPv4 and IPv6 routes can carry WebRTC traffic through the tunnel like anything else. The failure mode is incomplete routing, not WebRTC itself.
Is a single IP leak test enough to confirm I’m anonymous?
No. A clean test means no leak was detected by those specific checks that’s network-path consistency, not anonymity. Canvas, font and audio signatures, account history, authentication state and behaviour are all separate identity surfaces. Full protection requires leak prevention and fingerprint spoofing together, which is what a properly configured anti-detect browser delivers.
How often should I run an IP leak test?
Run a full leak test whenever you set up a new profile, change proxies, or update your browser. Many leaks are introduced by software updates that quietly reset privacy settings, or by proxy providers switching infrastructure. A monthly check on active profiles is a sensible baseline.