IPv6 test
The test tries IPv4 and IPv6 separately and shows which one your browser uses when it can choose.
IPv6 readiness
Testing …
IPv4
Testing …
IPv6
Testing …
When both are available
Testing …
The test contacts Cloudflare at 1.1.1.1 and quaestio.app, which therefore see your IP address. Nothing is stored.
How it works
IPv4 has just over 4.3 billion addresses, and IANA’s central pool ran out in 2011. In Europe, the RIPE NCC handed out its last regular IPv4 blocks in November 2019. IPv6 addresses are 128 bits long, enough for every device to have its own public address, and most mobile networks and many broadband providers already offer it.
The test makes three requests at once. The first goes to Cloudflare’s server at 1.1.1.1 and can only be reached over IPv4, the second to 2606:4700:4700::1111 and can only be reached over IPv6. The third goes to quaestio.app, which has both an IPv4 and an IPv6 address, and shows which version your browser picks. A request with no answer within eight seconds counts as failed.
When both work, browsers following Happy Eyeballs (RFC 8305) usually try IPv6 first and switch to IPv4 if IPv6 does not answer within a short delay, which the standard recommends should be 250 milliseconds. If IPv4 is used even though IPv6 works, the IPv6 path may have been slow, or the browser may have reused a connection that was already open.
The score is 10 when IPv6 works and is used, 8 when IPv6 works but the browser chose IPv4, and 0 without IPv6. Tunnels such as 6to4 (addresses starting 2002:) and Teredo (2001:0:) cost three points, as they are often slow and unreliable and are not real IPv6 from your provider.
If IPv6 does not work, you usually do not need to do anything, since everything still works over IPv4. If you want IPv6, ask your provider whether they offer it and check that IPv6 is switched on in your router. A VPN can hide or disable IPv6. Some firewalls block the address 1.1.1.1; the IPv4 result is then based on the answer from quaestio.app instead.
The IPv6 address shown is often a temporary address that your computer changes regularly to make it harder to track (RFC 8981). The first 64 bits identify the network and come from your provider, so they are the same for every device on your home network.