A failed request is a clue, not a diagnosis
The IPv6 check asks your browser to reach our IPv6 endpoint. A successful result shows the IPv6 source address used on that path. A failure can come from DNS, a blocked request, TLS, a VPN, a timeout, the test service, or your network. It does not by itself mean that your ISP has no IPv6.
Dual-stack websites can still load when one family is broken. Browsers can try multiple addresses and choose a working connection, so normal browsing is not a complete IPv6 test.
Worked example: only a link-local address
A laptop shows fe80::1234 on Wi-Fi and no other IPv6 address. That is a link-local address: it works on the local link and is not evidence of Internet IPv6. Start at the router’s IPv6 status and ISP prefix delegation rather than changing the website’s DNS record.
If the laptop has an Internet-routable IPv6 address but no default IPv6 route, address assignment succeeded while routing is incomplete. If both exist, a forced HTTPS request helps narrow the problem further.
# Linux: inspect addresses and the default route
ip -6 address show
ip -6 route show default
# macOS / Linux / curl.exe on Windows
curl -6 --connect-timeout 5 --max-time 10 https://myip.dk/api/ipWork outward from your device
Keep a note of which step fails so an ISP or network administrator has something specific to investigate.
- Retry once and compare another browser or device on the same network.
- Check whether a VPN or security tool disables or separately routes IPv6.
- Check the router’s IPv6 connection and delegated prefix, then the device address and default route.
- Use the DNS lookup tool to see whether the destination publishes an AAAA record. The presence of an AAAA record alone does not establish reachability.
- Compare another network, such as a phone hotspot. A working result there narrows the issue to the original connection or its configuration.
Read the result narrowly
A successful HTTPS check is an application connection to one destination. It does not test every IPv6 route, incoming reachability, MTU behavior, or every application. The displayed request time includes application and network work; it is not an ICMP ping or a broadband speed measurement.
Some networks translate between IPv6 and IPv4. A public IPv4 observed by a website can therefore be a translator’s address rather than native IPv4 assigned to your device.