AAAA record
The IPv6 equivalent of an A record. Maps a hostname to an IPv6 address (128-bit, written in colon-separated hex groups).
An AAAA record (pronounced "quad-A") maps a hostname to an IPv6 address. Same idea as an A record, but for IPv6 instead of IPv4.
example.com. AAAA 2606:2800:21f:cb07:6820:80da:af6b:8b2c ; TTL 3600
Why "AAAA"
A records hold 32-bit addresses. AAAA records hold 128-bit addresses, which is four times as much data. The name is a literal pun on the size difference.
Do you need AAAA records?
If you serve any traffic from mobile networks (where IPv6 adoption is high in many countries, especially the US and India), having AAAA records improves latency for some users by skipping a fallback step.
Practical guidance:
- Have both A and AAAA records for your apex and your main service hostnames.
- Don't worry if you have only A records on every internal hostname.
- If you're a SaaS offering custom domains, make sure your edge has AAAA records, otherwise your customers' IPv6 users hit a NAT64 gateway adding 50–100ms latency.
How resolvers pick
A client (browser, app) typically queries for both A and AAAA records. If both come back, it tries the IPv6 connection first (RFC 6555, "Happy Eyeballs"), falling back to IPv4 if the IPv6 attempt is slow or fails.