DNS AAAA Record: IPv6 Addresses Explained
A DNS AAAA record maps a hostname to an IPv6 address. It is the IPv6 counterpart of the classic A record: where an A record points a name to a 32-bit IPv4 address, an AAAA record points the same name to a 128-bit IPv6 address. The name "AAAA" (spoken "quad-A") reflects that an IPv6 address is four times the size of an IPv4 one.
What is an AAAA record?
Defined in RFC 3596, the AAAA record is how the modern internet advertises IPv6 connectivity. When a browser wants to reach example.com over IPv6, it asks a resolver for the domain's AAAA record and connects to the address it returns. Most large sites publish both an A and an AAAA record so that clients on either protocol can reach them — a setup called dual-stack.
AAAA record structure and example
In a zone file an AAAA record is a name, a TTL, the class, the type, and a single IPv6 address:
example.com. 3600 IN AAAA 2606:2800:220:1:248:1893:25c8:1946| Field | Meaning |
|---|---|
| Name | The hostname the record applies to (example.com). |
| TTL | Time to live in seconds — how long resolvers cache the answer. |
| Type | Always AAAA for IPv6 address records. |
| IPv6 address | The 128-bit destination, written as eight groups of hexadecimal separated by colons. Leading zeros in a group can be dropped and one run of all-zero groups can be collapsed to ::. |
How to check a domain's AAAA record
# dig (Linux/macOS)
dig example.com AAAA +short
# nslookup (Windows/cross-platform)
nslookup -type=AAAA example.comAn empty result usually means the domain simply has no IPv6 address published yet — that is common and not an error. To see the AAAA record next to every other record for a domain in one place, use the free DNS lookup tool.
A record vs AAAA record
| A record | AAAA record | |
|---|---|---|
| Address family | IPv4 | IPv6 |
| Address size | 32-bit | 128-bit |
| Example value | 93.184.216.34 | 2606:2800:220:1:248:1893:25c8:1946 |
| Defined in | RFC 1035 | RFC 3596 |
They are not mutually exclusive: publishing both is the recommended dual-stack configuration.
Common AAAA record issues
- Publishing an AAAA record with no working IPv6 path. If the record exists but the server or network cannot actually be reached over IPv6, dual-stack clients may hang before falling back to IPv4. Only publish an AAAA record once the address genuinely responds.
- Mismatched A and AAAA content. If the two records point at different back-ends, users can silently land on the wrong server depending on their protocol.
- Forgetting AAAA in a migration. Moving hosts and updating only the A record leaves IPv6 visitors on the old address until the AAAA record is fixed too.
Related DNS records
Mapping a domain end to end means reading more than one record type. The SOA record defines the zone and its refresh timers, NS records delegate it to authoritative name servers, and PTR records provide the reverse mapping from an IPv6 or IPv4 address back to a hostname.
Frequently asked questions
Do I need an AAAA record?
You need one only if you want your domain reachable over IPv6. It is not mandatory, but adding a correct AAAA record improves reach for the growing share of IPv6-only clients and mobile networks.
Why does "AAAA" mean IPv6?
An IPv6 address (128 bits) is four times the length of an IPv4 address (32 bits), so the record type that carries it was named with four A's.
Can a hostname have both A and AAAA records?
Yes, and it usually should. Serving both is the standard dual-stack setup and lets clients pick whichever protocol they support.