AAAA record

Also known as: AAAA records, quad-A record

DNS record mapping a name to an IPv6 address. The IPv6 equivalent of an A record.

Pronounced quad-A. Modern operating systems and browsers prefer IPv6 when both A and AAAA are published, falling back to IPv4 if IPv6 fails. Managed hosts (Cloudflare, M365, AWS managed services) usually publish AAAA records automatically. Mismatched A/AAAA targets on a migration are a common failure mode: IPv6-capable users see one server and IPv4-only users see another.