AAAA

networking

Stands for: AAAA record (IPv6 address record)

The DNS record that maps a hostname to an IPv6 address.

An AAAA record (RFC 3596) is the IPv6 counterpart of the A record - four times the bits, hence 'quad-A'. A name can have both A and AAAA records for dual-stack reachability.

An AAAA record maps a name to an IPv6 address, the counterpart to the A record's IPv4. The name is four times A, for an address four times the size.

The operational subtlety is what happens when one is wrong. A client with working IPv6 prefers the AAAA answer, so publishing an AAAA for a host whose IPv6 path is broken makes the service appear down to dual-stacked users while remaining perfectly reachable for everyone else. That asymmetry is the source of the classic report where a site is down for some people and fine for others, and the first diagnostic is to resolve both record types and test each address family separately.

Also known as: aaaa, quad-A, AAAA record

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