IPv6 via VPN	You have IPv6, and it goes through your VPN. Websites see the VPN's IPv6 address.
No IPv6	Your VPN is on and there's no IPv6 address. Either the VPN blocks IPv6 or your connection doesn't have it, so nothing can leak over it.
IPv6 supported	No VPN. Your provider gives you a working IPv6 address.
IPv6 not supported	No VPN. Your connection only uses IPv4. Websites still work normally.
Unable to verify	You're on a VPN and have IPv6, but the lookup service couldn't confirm who owns the address. Run the test again.
IPv6 leak detected	Your VPN is on, but your real IPv6 address from your internet provider is still visible to websites.

What Is IPv6?

Every device on the internet needs an IP address. The original system, IPv4, has room for about 4.3 billion addresses, and they ran out years ago. IPv6 is its replacement, with enough addresses for every phone, laptop and smart TV for the foreseeable future.

Most connections today run both at once. Your browser prefers IPv6 when the website supports it (Google, Facebook, Netflix and most large sites do) and falls back to IPv4 when it doesn't. That's why a website may see either of your two addresses, depending on the site.

	IPv4	IPv6
Example	`203.0.113.42`	`2001:db8:85a3::8a2e:370:7334`
Length	32 bits, 4 numbers	128 bits, 8 groups of hex digits
Available addresses	About 4.3 billion	About 340 undecillion (3.4 × 10³⁸)
Home network	One shared public address, devices hidden behind the router (NAT)	Each device gets its own public address
Who sees it	Websites without IPv6	Websites that support IPv6

Does My Internet Provider Support IPv6?

In the US, most likely yes. Roughly half of American users already reach Google over IPv6, and nearly all large home and mobile providers hand out IPv6 addresses by default:

Provider	IPv6
Comcast Xfinity	Yes, on by default
Charter Spectrum	Yes, on by default
AT&T Fiber	Yes, on by default
Cox	Yes, on by default
T-Mobile (phones and Home Internet)	Yes, IPv6 is the main protocol
Verizon Wireless	Yes, on by default
Starlink	Yes

If you're with one of these providers and the test says IPv6 not supported, the usual cause is your own router: older models don't support IPv6, and some have it turned off. Check the router's WAN or internet settings for an IPv6 option, set it to automatic (DHCPv6 or SLAAC), and restart it. If you rent the router from your provider, a newer model often fixes it.

The IPv6 provider row in the test shows which network your IPv6 address belongs to. More details about your provider and its ASN are on the Network Information page.

IPv6 and Your Privacy

An IPv6 address reveals about as much as an IPv4 address: your internet provider and your approximate location. There is one difference worth knowing.

An IPv6 address has two halves. The first half, the network prefix, is assigned to your home or your phone by your provider and usually stays the same for weeks or months. The second half identifies the device. Windows, macOS, iOS and Android change the second half regularly (a feature called privacy extensions or temporary addresses), but the prefix alone is often enough for a website to recognize your household.

With IPv4, your whole household shares one address. With IPv6, each device has its own, so a website can tell your laptop and your phone apart even on the same Wi-Fi. A VPN hides both, as long as it tunnels IPv6.

Can Your IPv6 Address Reveal Your MAC Address?

Every network card has a hardware ID called a MAC address, set at the factory. Some devices build the second half of their IPv6 address from it, using a method called EUI-64. You can spot it by ff:fe in the middle of the second half, for example 2601:647:4d00:1a2:021a:2bff:fe3c:4d5e.

That's a privacy problem because the MAC address never changes. Wherever you take the device, at home, at work or on hotel Wi-Fi, the second half of its IPv6 address stays the same, and any website can use it to recognize the device. The MAC address in IPv6 row in the test shows whether your address contains one.

Windows, macOS, iOS and Android avoid this by default with random addresses (privacy extensions). EUI-64 still turns up on older Linux setups, some routers, and smart TVs and other smart devices. If the test shows Exposed:

Windows: open Terminal or Command Prompt as administrator and run netsh interface ipv6 set privacy state=enabled and netsh interface ipv6 set global randomizeidentifiers=enabled, then restart.
Linux: set net.ipv6.conf.all.use_tempaddr = 2 and net.ipv6.conf.default.use_tempaddr = 2 in /etc/sysctl.conf, or turn on IPv6 privacy in NetworkManager.
Mac, iPhone, Android: random addresses are on by default. If the test still shows Exposed, check that no configuration profile or network tool has turned IPv6 privacy off, then reconnect to the network.

What Is an IPv6 Leak?

Some VPNs only tunnel IPv4 traffic. Your device keeps its working IPv6 address from your provider, and because browsers prefer IPv6, every site that supports it connects around the VPN. The site sees your real IPv6 address, and with it your provider and location, while the VPN app still shows Connected.

The test checks this when it detects a VPN. It looks up who owns your IPv6 address. If it belongs to your VPN or a data center, you're protected. If it belongs to a home or mobile provider such as Comcast or T-Mobile, your IPv6 traffic bypasses the VPN.

How to Fix an IPv6 Leak

Turn on IPv6 leak protection in your VPN app

Most major VPNs have it in their settings, often next to the kill switch. It blocks IPv6 while the VPN is connected.

Or use a VPN that tunnels IPv6

Some providers, such as Mullvad, route IPv6 through the tunnel instead of blocking it, so websites see the VPN's IPv6 address and IPv6-only sites keep working.

Disable IPv6 on your device if your VPN can't do either

Windows: Control Panel → Network and Sharing Center → Change adapter settings → right-click your connection → Properties → uncheck Internet Protocol Version 6 (TCP/IPv6). Mac: System Settings → Network → your connection → Details → TCP/IP → set Configure IPv6 to Link-local only, or open Terminal and run networksetup -setv6off Wi-Fi (replace Wi-Fi with the name of your connection).

Run this test again

Keep the VPN connected and reload this page. The result should be IPv6 via VPN or No IPv6.

An IPv6 leak rarely comes alone. Run the VPN Test to check DNS and WebRTC at the same time, or see the guide Is Your VPN Leaking? for every fix step by step.

Should You Disable IPv6?

For most people, no. IPv6 doesn't make you less safe on its own, and turning it off can cause problems: T-Mobile and other mobile carriers rely on it, some games and video calls connect faster over it, and Microsoft recommends keeping it enabled in Windows.

Disable it only as a workaround when your VPN leaks IPv6 and offers no fix. If you do, write down what you changed, so you can turn it back on after switching to a VPN that handles IPv6 properly.

The Verdict: IPv6 Is Fine, Leaks Aren't

Having IPv6 is normal and nothing to fix. Most US connections have it, and it doesn't expose more about you than IPv4.

The risk is a VPN that ignores it. If this test shows an IPv6 leak, your real address reaches every IPv6-capable website. Choose a VPN that tunnels or blocks IPv6 and test again after every update.

Compare VPNs That Pass Leak Tests

Frequently Asked Questions

How do I know if I have IPv6?

Open this page. The test tries to reach an IPv6-only server from your browser. If it succeeds, you have IPv6 and the page shows your IPv6 address. If it fails, your connection only uses IPv4.

Why does my IPv6 test fail?

The most common reason is the router. Many providers support IPv6, but older routers or routers with IPv6 turned off in their settings only pass IPv4. Other causes are a provider that doesn't offer IPv6 in your area, IPv6 disabled on your computer, or a VPN that blocks IPv6.

Is IPv6 faster than IPv4?

Sometimes slightly. IPv6 skips the address translation (NAT) that IPv4 needs, which can shave a few milliseconds off connections, especially on mobile networks. For everyday browsing and streaming you won't notice a difference. To measure your connection, use the Speed Test.

Should I disable IPv6?

Usually not. IPv6 is the future of the internet, and mobile carriers such as T-Mobile rely on it. Disable it only if your VPN leaks your IPv6 address and has no IPv6 leak protection. In that case, switching to a VPN that handles IPv6 is the better long-term fix.

Can websites track me by my IPv6 address?

Yes, in the same way as with IPv4. The first half of your IPv6 address (the network prefix) is assigned to your home or phone and usually stays the same for weeks or months. Windows, macOS, iOS and Android change the second half regularly, but the prefix alone is often enough to recognize your household.

Can my IPv6 address reveal my MAC address?

It can. Some devices build the second half of their IPv6 address from the network card's hardware (MAC) address, a method called EUI-64. That address never changes, so any website can recognize the device on every network. Windows, macOS, iOS and Android use random addresses instead, but older Linux systems, some routers and some smart devices still use EUI-64. This test checks your address for it.

What is an IPv6 leak?

An IPv6 leak happens when your VPN only tunnels IPv4 traffic. Your device still has a working IPv6 address from your internet provider, so websites that support IPv6 connect over it and see your real address instead of the VPN's.