CloakMyIPAddress

IPv6 Leak Test: Is Your VPN Leaking Your IPv6 Address?

Check whether your IPv6 address is visible while on a VPN, why IPv6 leaks happen, and how to fix them on Windows, macOS, Android, iPhone and routers.

By CloakMyIPAddress Privacy Desk Published

Disclosure: Some links go to VPN providers via our /go/ links and may earn us a commission in future, at no cost to you. Disclosure

On this page
  1. IPv4 vs IPv6 in plain terms
  2. How an IPv6 leak happens
  3. Does IPv6 identify me more than IPv4?
  4. How to run the test
  5. How to fix an IPv6 leak
  6. 1. In your VPN app
  7. 2. Windows
  8. 3. macOS
  9. 4. Android
  10. 5. iPhone and iPad
  11. 6. Router
  12. Should you just turn IPv6 off?
  13. Troubleshooting: common IPv6 test results
  14. IPv6 and VPN checklist
  15. Related tests
  16. FAQ
  17. Sources

Last reviewed: 30 October 2026 · By the CloakMyIPAddress Privacy Desk

Live test

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Leak test

Checks whether WebRTC exposes a different IP than the one websites see, which DNS resolvers handle your lookups, and whether IPv6 takes a different route than IPv4.

Browser

Quick answer: your internet provider may give you both an IPv4 and an IPv6 address. If your VPN only handles IPv4, any website reachable over IPv6 sees your real IPv6 address. Run the test with your VPN connected: if an IPv6 address from your home provider appears, you have a leak. Fix it by enabling your VPN’s IPv6 leak protection, or by disabling IPv6 on your device or router.

IPv4 vs IPv6 in plain terms

  • IPv4 addresses look like 203.0.113.45. There are only about 4.3 billion, so providers share them using NAT.
  • IPv6 addresses look like 2001:db8:85a3::8a2e:370:7334. There are enough for every device to have a globally unique one.

Many European providers now offer IPv6 by default on fibre and mobile networks. When both are available, your device often prefers IPv6 for sites that support it (the “Happy Eyeballs” algorithm, RFC 8305, picks whichever connects fastest).

How an IPv6 leak happens

  1. Your VPN connects and routes IPv4 traffic through the tunnel.
  2. Your device still has a working IPv6 address from your provider.
  3. You visit a site that supports IPv6 (Google, Facebook, Netflix and many others do).
  4. Your device connects over IPv6 — outside the tunnel — and the site sees your real IPv6 address, which maps to your provider and location.

Well-designed VPN apps prevent this by either tunnelling IPv6 too or blocking IPv6 while connected. Older apps, manual configurations and some routers don’t.

Does IPv6 identify me more than IPv4?

An IPv6 address has two halves: a network prefix (typically the first 64 bits, assigned by your provider to your connection) and an interface identifier. Early implementations built the identifier from the device’s MAC address, which made devices trackable. Modern Windows, macOS, iOS, Android and Linux use temporary, randomised addresses for outgoing connections (RFC 8981), rotating them regularly. But the prefix still identifies your home connection — so a leak is roughly as revealing as an IPv4 leak.

How to run the test

  1. VPN off: run the test. If you see “No IPv6 connectivity”, your network doesn’t use IPv6 and you can’t leak it (re-test on other networks, e.g. mobile data).
  2. If you do see an IPv6 address, note its beginning (your provider’s prefix).
  3. VPN on, kill switch on: run the test again.
  4. Pass: “No IPv6 connectivity”, or an IPv6 address belonging to your VPN provider.
  5. Leak: your provider’s IPv6 prefix appears.

How to fix an IPv6 leak

1. In your VPN app

Look for “IPv6 leak protection”, “Block IPv6” or “Enable IPv6 support”. Update the app; many leak fixes ship silently. Mainstream providers’ official apps — such as Mullvad, Proton VPN, NordVPN and Surfshark — handle IPv6 either by tunnelling it or blocking it; check the provider’s current documentation and re-test.

2. Windows

Settings → Network & internet → Advanced network settings → your adapter → More adapter options → Edit → untick Internet Protocol Version 6 (TCP/IPv6). Re-enable it when you stop using the VPN if you need IPv6.

3. macOS

System Settings → Network → select Wi-Fi or Ethernet → Details → TCP/IP → Configure IPv6: Link-local only.

4. Android

There’s no simple IPv6 switch. Use Always-on VPN with Block connections without VPN and a VPN app that handles IPv6. For mobile data, some phones let you set APN protocol to IPv4 (Settings → Network → Access Point Names) — operator-dependent.

5. iPhone and iPad

No user setting to disable IPv6. Use a VPN app that tunnels or blocks IPv6 and re-test on both Wi-Fi and mobile data.

6. Router

Many routers can turn IPv6 off for the whole home network (often under WAN/Internet → IPv6). This fixes all devices at once, at the cost of losing IPv6 on the network.

Should you just turn IPv6 off?

It’s a valid quick fix if your VPN doesn’t support it. But IPv6 is the future of the internet, and some networks (especially mobile) work better with it. The better long-term fix is a VPN that supports IPv6 properly.

Troubleshooting: common IPv6 test results

“IPv6 detected” with VPN off, “No IPv6” with VPN on. This is the result you want: your VPN is blocking IPv6 while connected. You lose IPv6 only while the VPN is on.

Your provider’s IPv6 appears with the VPN on. Classic leak. Update the VPN app, turn on IPv6 leak protection and the kill switch, then reconnect. If it still leaks, disable IPv6 on the device or router as above, and tell the VPN provider — reputable providers treat leak reports as security bugs.

An IPv6 address from a different provider appears. If it belongs to your VPN provider, your VPN tunnels IPv6 natively — also a pass. Check the owner name shown in the result.

The result changes between Wi-Fi and mobile data. Mobile networks increasingly run IPv6-first (sometimes IPv6-only with translation to IPv4). Test on both, because a VPN that’s safe at home can behave differently on a mobile network.

The test works in one browser and not another. IPv6 handling is system-wide, so differences between browsers usually point to a browser proxy or extension. Disable extensions and re-test.

IPv6 and VPN checklist

  1. Run the IPv6 test with the VPN off and on.
  2. Turn on the kill switch and any “block IPv6” option.
  3. Re-test on Wi-Fi and mobile data.
  4. Run the WebRTC and DNS tests as well — a VPN can pass one and fail another.
  5. Re-test after every major OS or VPN app update.

FAQ

What is an IPv6 leak? IPv6 traffic bypassing an IPv4-only VPN tunnel.

Should I disable IPv6? Only if your VPN doesn’t handle it and you see a leak.

Is IPv6 less private? Not inherently; temporary addresses help, but the prefix identifies your connection.

Sources