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VPN Leak Test

By Vathanakone Prakosay · Updated on · 5 min read

In short

This VPN leak test checks three things while your VPN is on: which public IP websites see, whether your IPv6 address bypasses the VPN and whether WebRTC reveals another address. If every address belongs to your VPN provider, your VPN does not leak your IP.

VPN leak testruns in your browser

The test asks ipinfo.io ↗ for your public IP and its owner, icanhazip.com ↗ for your IPv6 address and a STUN server of Google ↗ for WebRTC addresses. DNS is not tested here (see below). Nothing runs until you click. Results stay in your browser; we do not store or receive them. Checks marked ↗ send one request to a third party (see Privacy, section 3.3).

    How does this VPN leak test work?

    The VPN leak test runs three checks in your browser and shows who owns each address it finds.

    1. IP check: ipinfo.io returns your public IP address, its location and the network owner (ASN).
    2. IPv6 check: icanhazip.com returns your IPv6 address, if your connection has one. If it belongs to a different network than your main IP, the test flags an IPv6 leak.
    3. WebRTC check: your browser asks a STUN server for the addresses WebRTC exposes. A public address from another network is a possible leak.

    Steps to test: run it once without the VPN and note the network owner. Then connect to a VPN server and run it again. The second result should show your VPN provider, not your ISP.

    How do I read the VPN leak test result?

    Your VPN is working if the network owner is your VPN provider and the test finds no address from another network.

    LineGood result with the VPN onLeak sign
    Public IPOwner is your VPN provider or a hosting networkOwner is your home ISP: the VPN is off or the traffic is not routed through the VPN
    IPv6No IPv6, or the same network as the IPIPv6 from your ISP: IPv6 leak
    WebRTCNo address from another networkAddress from your ISP: WebRTC leak
    DNSNot tested hereUse a full DNS leak test

    What is a VPN leak?

    A VPN leak is any traffic or data that leaves your device outside the encrypted tunnel and reveals your real IP address or your online activity. The four common types are:

    IPv6 leaks are not rare. In a 2015 study of 14 popular commercial VPN services, most of them leaked IPv6 traffic (Perta et al., 2015).

    Why does this page not run a full DNS leak test?

    A browser cannot see which DNS server your system uses. A real DNS leak test needs its own DNS server: your device looks up random test names, and the server records which resolver asked. That is why this page only gives a hint and links to a full test. Our DNS leak test guide explains how to run one and how to prevent DNS leaks, for example with DNS leak protection in your VPN app or with encrypted DNS such as DNS over HTTPS (RFC 8484, 2018).

    How do I fix a VPN leak?

    Most VPN leaks go away with the right app settings. Change one setting at a time and run the VPN leak test again.

    When should I run a VPN leak test?

    Run it after you install a VPN, after you change the VPN protocol or server, after a system or app update and after you switch networks, for example from home Wi-Fi to public Wi-Fi. A connection that was fine yesterday can leak after an update.

    What can this VPN leak test not see?

    It only sees this browser and this moment. Apps outside the browser, a VPN that reconnects later and DNS requests are outside its view. A VPN also does not stop browser fingerprinting: run the browser fingerprint test to see what your browser reveals regardless of your IP. If your VPN works but feels slow, the VPN speed test guide explains how to measure it fairly.

    FAQ

    How do I know if my VPN is leaking?

    Run the VPN leak test with the VPN on. If the public IP or the IPv6 address belongs to your home ISP, or WebRTC shows an address from your ISP’s network, your VPN is leaking. Then run a full DNS leak test as well.

    Can sites tell that I am using a VPN?

    Often, yes. Many VPN servers sit in hosting networks, and the network owner of your IP shows that. A VPN hides your real IP address, not the fact that you use a VPN.

    Can a VPN prevent a DNS leak?

    Yes, if the app sends DNS requests through the tunnel. Many apps call this DNS leak protection. Only a full DNS leak test with its own DNS server can confirm it.

    Does a VPN slow down my internet?

    Usually a little, because traffic is encrypted and travels to the VPN server first. Compare a speed test with and without the VPN; the VPN speed test guide shows how.

    Is the VPN leak test free?

    Yes. It needs no account, shows no ads and does not store your results.

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    Sources