An AAAA record is a DNS resource record that associates a domain name with a 128-bit IPv6 address. It is the IPv6 equivalent of the A record, which maps domains to 32-bit IPv4 addresses. Defined in RFC 3596, AAAA records enable IPv6-capable clients to resolve and connect to hosts on the modern IPv6 internet.
How it works
When a DNS resolver queries a domain with QTYPE=28 (the AAAA record type code), the authoritative nameserver responds with the raw IPv6 address in RDATA format. A zone file entry looks like:
example.com. 3600 IN AAAA 2606:2800:220:1:248:1893:25c8:1946
Most domains publish both A and AAAA records for dual-stack support (IPv4 and IPv6). Modern clients use "Happy Eyeballs" (RFC 8305) to query both record types in parallel and race the connection attempts, so that a broken IPv6 path does not block or delay the IPv4 fallback.
When it matters
Publishing an AAAA record without proper IPv6 connectivity (bad routing, firewall rules, misconfigured interfaces) can cause clients to hang or fail when they attempt to use the advertised IPv6 address. If your server supports IPv6, ensure the entire path works end-to-end. Use DNS lookup to verify your AAAA records are correctly published.
NoteAn AAAA record is simply the IPv6 equivalent of an A record. Publishing both an A and an AAAA record for the same hostname lets clients reach you over either protocol.