AAAARecord

An AAAA record, also known as a quad-A record, is a type of DNS resource record used to map a domain name to an IPv6 address. It is defined in RFC 3596 and is the IPv6 equivalent of the A record for IPv4 addresses. An owner of a domain can publish one or more AAAA records to indicate the IPv6 endpoints for that name.

When a DNS resolver queries a name, the DNS server may respond with one or more AAAA records containing IPv6 addresses. Clients use these addresses to establish connections. A domain may include multiple AAAA records to enable load balancing or redundancy. If no AAAA records are available, and the client only supports IPv6, the resolution may fail; in dual-stack environments, resolvers often query both A and AAAA records.

The data portion of an AAAA record contains a 128-bit IPv6 address, written in standard IPv6 notation (for example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334). Compression rules allow zero-compression, so it is commonly written as 2001:db8:85a3::8a2e:370:7334.

Publishers should consider DNS security and privacy implications; DNSSEC can be used to provide authenticity, and some environments deploy privacy-preserving IPv6 address schemes. AAAA records coexist with A records in dual-stack configurations.

See also: A record, DNS, IPv6, reverse DNS, DNSSEC.