IPv6 Connectivity Test
Find out whether this connection actually used IPv6 — not whether it could.
Where this comes from
The address the edge saw is read and its family reported. That is deliberately not a capability check: “your browser supports IPv6” and “your traffic went over IPv6” are different claims, and only the second one describes what actually happens when you use the internet. Browsers implement Happy Eyeballs, trying both and preferring IPv6 where it answers first — so a machine that has IPv6 configured but cannot route it falls back within a fraction of a second and looks fully enabled from the inside. Reading the address at the far end is the only way to know which one carried the request.
What the results mean
- Version used
- Which family carried this request. The claim that matters.
- IPv4-mapped IPv6
- An IPv4 connection in a v6-shaped container somewhere in the path. Functionally IPv4.
- Fallback is invisible
- Browsers try both and prefer IPv6. A failure takes a fraction of a second and shows no symptom.
- VPN
- The commonest reason IPv6 disappears. Many carry IPv4 only.
Common problems and fixes
- My router says IPv6 is enabled but this shows IPv4
- Enabled locally is not the same as routed. Check whether your ISP actually provides IPv6 — a router can hand out addresses on the local network that go nowhere.
- It worked yesterday and not today
- A VPN is the usual answer. Many carry IPv4 only, so connecting one removes IPv6 entirely.
- Should I care?
- Mostly no, for browsing. It matters for peer-to-peer connections, some games, and carrier-grade NAT situations where IPv4 puts you behind a shared address.
Frequently asked questions
Why does a capability check disagree with this?
Because they answer different questions. A capability check asks whether your machine can form an IPv6 connection; this reports which family carried the request that fetched the page. A machine that can try and always falls back passes the first and fails the second.
What is Happy Eyeballs?
The browser behaviour of attempting both families at once and using whichever answers first, with a slight preference for IPv6. It is why a broken IPv6 path produces no visible symptom at all.
Does a VPN break IPv6?
Frequently. Many VPNs tunnel IPv4 only, and some block IPv6 outright to prevent a leak — which is the right call for privacy and does mean your connection is IPv4 while it is on.
Put this on your own site
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