What Is an AAAA Record?
An AAAA record ("quad-A") is the DNS record that maps a domain name to an IPv6 address — the IPv6 counterpart of the familiar A record, which maps a name to an IPv4 address. When a browser opens a site it looks up both records; the client's own address selection (commonly "Happy Eyeballs") then decides which to connect over — typically trying IPv6 (the AAAA record) first when it has working IPv6, and using IPv4 (the A record) otherwise.
A domain that publishes both an A and an AAAA record is dual-stack; one that publishes only an AAAA record is IPv6-only. Publishing an AAAA record is what makes a site reachable for IPv6-only clients — but a record pointing at a host that isn't actually listening on IPv6 still fails, which is why reachability needs testing, not just configuration.
IPv6 Proxy fetches any address over native IPv6 only, so you can confirm an AAAA record is not merely present but actually served. Enter a domain below to check whether it really answers over IPv6.