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VPNs & DNS

What Is an IPv6 Leak, and How Do You Fix It?

Updated · 2 min read

Written by the ScanMyPrivacy team. How we write and check guides · Report a correction

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An IPv6 leak happens when your device sends some of its internet traffic over IPv6 straight to the internet, outside your VPN tunnel. The VPN keeps protecting your IPv4 traffic, so it looks as if everything works, while the IPv6 part reveals your real address to any site that supports it.

Why IPv6 leaks happen

The internet runs two address systems side by side: IPv4 and IPv6 (see IPv4 vs IPv6). Many connections have both. A VPN has to tunnel both, or block the one it cannot handle. Some VPN apps only create an IPv4 tunnel. Your device, seeing that a website offers an IPv6 address, prefers it and sends the request around the tunnel using your real IPv6 address from your provider.

Many websites and apps now support IPv6, so the leak is not a rare edge case on connections that have it.

Does your connection even have IPv6?

Not all do. Some home broadband plans, in India and elsewhere, still give only IPv4, while many mobile networks provide IPv6. Open the home page. If the IPv6 line says "Not detected", your connection has no IPv6 on this network, and an IPv6 leak cannot happen there. That can change when you move to a different network, so test again on mobile data or public Wi-Fi.

How to test for an IPv6 leak

  1. Disconnect the VPN and open the home page. Note whether an IPv6 address is shown and which provider it belongs to.
  2. Connect the VPN and reload the page.
  3. If the IPv6 line now shows the same provider as before, or an address you did not see through the VPN, you have a leak. If it shows "Not detected" or an address from the VPN's network, you do not.

The VPN check and the full privacy scan add context about what the sites see.

How to fix an IPv6 leak

  • Use a VPN with IPv6 support or IPv6 leak protection. Many apps have a setting named "Block IPv6" or "IPv6 leak protection". Turn it on.
  • Disable IPv6 on your network adapter. On Windows, open Network Connections, right-click your adapter, choose Properties and untick "Internet Protocol Version 6 (TCP/IPv6)". Re-enable it if you stop using the VPN and want it back.
  • Turn IPv6 off in the router if your device or router lets you. This covers every device on the network but also removes IPv6 for them when you are not on a VPN.

Retest after changing a setting. The leak should disappear, and your VPN leak checklist results should stay clean.

Is turning IPv6 off safe?

For most people yes. Everything keeps working over IPv4, and the internet still supports it for the foreseeable future. You may lose a little speed on a few services that prefer IPv6, but you gain a consistent address that your VPN actually covers.

Keep reading

IPv4 vs IPv6IPv4 vs IPv6 explained: address formats, why we need IPv6, how dual stack works and why a VPN that ignores IPv6 can reveal your real location.How to Check If Your VPN Is Leaking Your IP AddressA five-minute checklist to test your VPN for IP, DNS, WebRTC and IPv6 leaks, and what to do if any test fails. Free tools, no sign-up.Do VPNs Leak DNS?Why a VPN can still leak your DNS requests to your ISP, the common causes (IPv6, Windows, browser DoH) and how to test for and fix a DNS leak.VPN connected but your real IP is still visible: causes and fixesTest shows your real IP while the VPN says connected? Check IPv6, WebRTC, DNS, split tunnelling and a dropped tunnel in order, and how to confirm each.VPN vs Proxy vs TorVPN vs proxy vs Tor compared: what each hides, who can still see your traffic, speed, cost and which to choose for streaming, privacy or anonymity.How to Test Your VPN Kill SwitchA kill switch should cut your internet when the VPN drops. Here is a simple, safe way to test it with a repeating IP check, on Windows, Mac and Linux.

Frequently asked questions

Can an IPv6 leak happen if the VPN says it is connected?

Yes. The connected status only means the tunnel exists. It does not guarantee that every kind of traffic goes through it.

Do I need IPv6 for anything?

Not today. Almost every site still works over IPv4. Some networks, especially mobile ones, use IPv6 heavily, but they also provide IPv4 access.

Is an IPv6 address more identifying than an IPv4 one?

Often yes, because IPv6 addresses are not shared among many customers like IPv4 addresses behind carrier-grade NAT. That is why leaking one matters.