IP Address & Location · Network Tests
IPv6 Test
Check whether you have working IPv6, and whether it agrees with your IPv4 address.
One endpoint answers over IPv6 when your connection has it, the other only ever answers over IPv4. Comparing the two shows which families actually reach the internet.
Address families detected
Addresses reported
A page cannot force a connection to use IPv6, and reachability depends on the destination: a host with no AAAA record is only ever reachable over IPv4. This test therefore reports what these two endpoints negotiated right now, which is a strong indicator of IPv6 support but not a guarantee for every site you visit.
On this page
What the test can and cannot see
This test asks two endpoints for your public address. One of them, api64, answers over IPv6 whenever your connection has it and falls back to IPv4 when it does not. The other, api, only ever answers over IPv4. Comparing what comes back tells you which address families your connection can actually use.
What it cannot do is force anything. A browser has no switch that says use IPv6 now. Whether a request travels over IPv6 depends on your operating system having a global IPv6 address, your router passing it through, and the destination publishing an AAAA record that points at an IPv6 address. The result above is what those endpoints negotiated, which is a strong signal, not a worldwide guarantee.
Two families, two addresses
On a dual-stack connection you genuinely have two public addresses at once, one of each kind, and a site may see either. That is why the IP address test can show a different value on different visits.
Why IPv4 ran out
IPv4 is a 32-bit address space, which caps the internet at about 4.3 billion addresses. The last unallocated blocks were handed to the regional registries in 2011, and they have been rationing ever since. IPv6 was designed to replace it with 128-bit addresses, enough that every device could have an address without anyone counting. The transition has taken far longer than anyone expected, which is why both protocols run side by side today.
The shortage is not theoretical. It is why home routers do network address translation, mapping a whole household onto one public address, and why mobile carriers put thousands of subscribers behind carrier-grade NAT. As a result, one public IPv4 address can now stand for thousands of people, and geolocation against it can do no better than the shared gateway. See the IP geolocation test for what that does to accuracy.
How IPv6 is detected
The mechanism is deliberately simple, and it is worth understanding why that is enough. The address itself encodes its family. An IPv4 address is four decimal groups separated by dots, like 203.0.113.42. An IPv6 address is eight groups of hexadecimal digits separated by colons, like 2001:db8::1. So a page can tell which family it received just by looking at the string, with no special API and nothing to install.
The test leans on the fact that api64 sits behind a hostname with both an A record and an AAAA record. Your browser, following the operating system’s preference, will try IPv6 first. If the whole path supports it the request arrives over IPv6 and the endpoint echoes back an IPv6 address. If anything along the way lacks IPv6 the request simply falls back and an IPv4 address comes back instead.
That makes the shape of the returned string the entire answer. Colons mean IPv6 worked end to end. Dots mean it did not, and the reason could sit in your device, your router, your provider or the destination. The ASN and ISP lookup names the network, which sometimes helps you tell whether your provider supports IPv6 at all.
The VPN leak IPv6 creates
This is the reason an IPv6 test belongs next to a VPN. Many VPN clients still tunnel IPv4 only. When they do, the client rewrites your IPv4 route through the encrypted tunnel but leaves IPv6 traffic alone. If your device also has a native IPv6 address from your provider, requests to sites that publish an AAAA record can leave by the ordinary route, outside the tunnel, and arrive at the destination from your real address rather than the VPN’s.
Nothing about that is exotic or rare. It happens with some of the largest sites on the web precisely because they support IPv6 well. A site that wants to see past a VPN only has to prefer the connection that arrives over IPv6, and it will be looking at your provider’s address, not the exit server’s.
The fix is usually a setting, not a promise
If the panel above shows IPv6 detected while a VPN is connected, check your VPN client for an IPv6 setting or a leak-protection toggle, or disable IPv6 on the device for the duration. Treat any “we protect everything” claim as something to verify rather than assume.
If you have no IPv6
Seeing IPv4 only is not a fault. Large parts of the internet, including many home broadband providers and a good number of corporate networks, have never finished the upgrade, and mobile carriers often enable IPv6 only on newer equipment. Every service you use still speaks IPv4, so nothing breaks and nothing is lost for ordinary browsing.
If you want IPv6 and do not have it, the order to check is device, then router, then provider. Most operating systems enable it by default once they receive a router advertisement, so the usual blockers are a router with IPv6 switched off, a provider that has not deployed it, or a firewall rule that drops the protocol. Turning it on in the router is the single change that most people can make, and it either works immediately or not at all.
One caution for VPN users: enabling IPv6 at home without checking the VPN client is exactly the combination that produces the leak described above. Run the WebRTC leak test after any change to confirm your real address is not visible alongside the masked one.