An AAAA record maps a hostname to an IPv6 address. It is the IPv6 counterpart of the A record and is required for clients on IPv6-only networks.
AAAA records store 128-bit IPv6 addresses such as 2001:db8::1. As mobile carriers and ISPs continue rolling out IPv6, publishing a correct AAAA record ensures visitors on those networks can reach your site without falling back through translation gateways. A domain can have both an A record and an AAAA record; clients that support IPv6 generally prefer the AAAA answer.
Missing or stale AAAA records are a frequent cause of the mysterious 'works for me but not for them' bug, because the problem only shows up for users on IPv6 connections while everyone else sees a perfectly healthy site. This checker requests the AAAA record from many locations so you can confirm the IPv6 address is consistent everywhere and has finished propagating. If some resolvers return no AAAA record while others do, the change is still spreading through caches, or the record was only recently added and has not reached every region yet. Verifying IPv6 alongside IPv4 avoids surprising a growing slice of your audience, and it is the quickest way to rule out reachability problems that are specific to IPv6-only clients.
Frequently asked questions
- Do I need an AAAA record?
- Only if you want to serve visitors over IPv6. It is optional, but increasingly recommended as IPv6 adoption grows.
- Can a domain have both A and AAAA records?
- Yes. Dual-stack hosts publish both, and IPv6-capable clients typically prefer the AAAA record.