Enter a domain and this will look up the AAAA records for its website, its mail exchangers and its own nameservers — then open a connection over IPv6 to see whether the address it published actually answers.
This checker cannot reach the IPv6 internet right now.
DNS records below are still accurate — those lookups go out over IPv4. But no connection is being attempted, so nothing here is evidence that a site is unreachable over IPv6. Results are not being saved or re-checked until it comes back.
No network interface here holds a global IPv6 address.
Three questions, graded separately, because they often have different answers.
AAAA records for the domain and its www name, then an actual
HTTPS connection to the address that was published.
AAAA records for the mail exchangers. A domain with no MX records is marked N/A rather than failed — it receives no mail at all.
AAAA records for the zone's own nameservers. Without one, an IPv6-only resolver cannot look the domain up at all.
A record that does not answer is worse than no record at all.
Mobile networks in much of the world are IPv6-only, reaching the rest of the internet through translation that adds latency and breaks in ways that are hard to debug. A domain that answers natively over IPv6 skips all of it. The most common partial result here is a site that is reachable over IPv6 while its mail is not — usually because the mail is somebody else's service.
A published AAAA record that does not answer is worse than none at all: a visitor's browser tries it first and waits for it to fail. That is the case this tool exists to catch, and it is why the website check opens a real connection rather than trusting the record.