When you set up a domain, you almost certainly created an A record — the entry that points your domain to its server’s IPv4 address. The AAAA record is its counterpart for the modern internet: it points your domain to an IPv6 address. As the world runs out of IPv4 addresses and networks move to IPv6, the AAAA record is what lets visitors on IPv6 connections reach your site directly.
This guide explains what an AAAA record is, how it differs from an A record, how IPv6 DNS resolution works, how to create and check an AAAA record, and when you actually need one.
An AAAA record (pronounced “quad-A”) is a DNS record that maps a domain name to an IPv6 address — for example 2001:db8::1. It’s the exact equivalent of an A record, which maps to an IPv4 address like 185.15.43.160. The name comes from size: an IPv4 address is 32 bits (one “A”), an IPv6 address is 128 bits — four times larger, hence “AAAA.” A domain can have both, and modern hosts serve visitors over whichever protocol their connection supports.
Table of Contents
What is an AAAA record?
An AAAA record is a type of DNS record that maps a hostname to an IPv6 address. It does exactly what an A record does — connect a domain name to the numeric address of the server behind it — except the address is IPv6 instead of IPv4.
The curious name is about address size. An IPv4 address (like 185.15.43.160) is 32 bits long, and its DNS record is called an “A” record. An IPv6 address (like 2001:0db8:85a3::8a2e:0370:7334) is 128 bits — four times the size — so its record was named with four A’s: AAAA. It’s often read aloud as “quad-A.”
When a browser needs to reach your site over IPv6, it asks DNS for the domain’s AAAA record, gets back the IPv6 address, and connects. The mechanism is identical to an A-record lookup; only the address format differs.
A record vs AAAA record: the difference
They’re the same idea for two different versions of the Internet Protocol. The one distinction that matters is which IP version they point to:
| Aspect | A record | AAAA record |
|---|---|---|
| Points to | IPv4 address | IPv6 address |
| Address size | 32-bit | 128-bit |
| Example value | 185.15.43.160 | 2001:db8::1 |
| Format | Four decimal groups, dots | Eight hex groups, colons |
| DNS query type | A | AAAA |
Everything else — TTL, how it propagates, how it’s cached — behaves the same way for both. A domain can (and often should) have both an A record and an AAAA record, so visitors on either protocol can reach it.
How IPv6 DNS resolution works
IPv6 DNS resolution follows the same path as IPv4 — the difference is the record type requested and the address returned. When you open a site on a device with IPv6 connectivity:
- The browser asks the resolver for both the A record (IPv4) and the AAAA record (IPv6) for the domain.
- If an AAAA record exists and the device has a working IPv6 connection, the browser can connect over IPv6.
- If there’s no AAAA record, or IPv6 isn’t available, it falls back to the A record over IPv4.
Modern operating systems use an algorithm called Happy Eyeballs (RFC 8305) to decide: they try IPv6 and IPv4 almost simultaneously and use whichever connects first, so a broken IPv6 path never leaves the visitor stuck. This is why adding an AAAA record is safe — if IPv6 fails for some visitor, they transparently fall back to IPv4.
For the fundamentals of how any DNS lookup travels the network, see what DNS is and how it works and the port DNS uses.
How to create an AAAA record
You add an AAAA record in your DNS provider’s control panel (your registrar, host, or DNS service like Cloudflare). The fields are the same as an A record, except the value is an IPv6 address:
| Field | Value | Meaning |
|---|---|---|
| Type | AAAA | The record type |
| Name / Host | @ or www | Root domain, or a subdomain |
| Value / Points to | 2001:db8::1 | Your server’s IPv6 address |
| TTL | 3600 | Seconds cached (1 hour is typical) |
Get your server’s IPv6 address from your host (it’s alongside the IPv4 in your hosting or VPS control panel). Save the record, then allow for DNS propagation — an AAAA record propagates exactly like an A record, usually within a few hours.
Point the AAAA record only at an IPv6 address your server truly answers on. If you publish an AAAA record for an address that isn’t listening, IPv6 visitors can hit delays or failures before falling back to IPv4. Confirm your host supports IPv6 and the address responds before publishing.
How to check an AAAA record
To verify an AAAA record exists and returns the right IPv6 address, query it directly:
Linux/macOS: dig copahost.com AAAA
Windows: nslookup -type=AAAA copahost.com
Any platform: use an online DNS lookup tool and select "AAAA"If the command returns an IPv6 address, the record is live. An empty answer means there’s no AAAA record for that name — the domain is IPv4-only. You can also test real-world IPv6 reachability with a “test IPv6” tool, which checks whether your site is actually reachable over IPv6, not just whether the record exists.
Do you need an AAAA record?
Not strictly — a site with only an A record works fine for everyone, because virtually all networks still support IPv4. But adding an AAAA record has real upsides and, done correctly, no downside:
- Future-proofing. IPv4 addresses are exhausted; the internet is steadily moving to IPv6. An AAAA record means you’re reachable natively as that shift continues.
- Performance for IPv6 users. Visitors on IPv6-only or IPv6-preferred networks (common on mobile carriers) connect directly, without passing through translation gateways.
- No risk with fallback. Thanks to Happy Eyeballs, if IPv6 ever fails for a visitor, they fall back to IPv4 automatically.
The practical answer for most site owners: if your host supports IPv6, add the AAAA record. If it doesn’t, an A record alone is still perfectly functional today.
Frequently asked questions
What is an AAAA record?
An AAAA record is a DNS record that maps a domain name to an IPv6 address, such as 2001:db8::1. It’s the IPv6 equivalent of an A record, which maps to an IPv4 address. When a browser needs to reach a site over IPv6, it looks up the domain’s AAAA record to get the address.
What’s the difference between an A record and an AAAA record?
An A record points a domain to a 32-bit IPv4 address (like 185.15.43.160); an AAAA record points it to a 128-bit IPv6 address (like 2001:db8::1). They work identically otherwise — same TTL and propagation behavior. A domain can have both so visitors on either protocol can reach it.
Why is it called AAAA?
The name reflects address size. An IPv4 address is 32 bits and its record is called “A.” An IPv6 address is 128 bits — four times larger — so its record was named with four A’s: AAAA, often read as “quad-A.”
Do I need an AAAA record for my website?
Not required — an A record alone works for virtually all visitors since IPv4 is universally supported. But if your host supports IPv6, adding an AAAA record future-proofs your site and improves connectivity for IPv6 users, with automatic fallback to IPv4 if IPv6 fails.
How do I check my domain’s AAAA record?
Query it directly: dig copahost.com AAAA on Linux/macOS, or nslookup -type=AAAA copahost.com on Windows. You can also use an online DNS lookup tool and select the AAAA type. If it returns an IPv6 address, the record is live; an empty result means the domain is IPv4-only.
Copahost hosting includes an easy DNS editor with full support for A, AAAA, CNAME, MX and more — plus IPv6-ready servers and support that helps you get every record right.
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The AAAA record is simply the A record’s IPv6 twin: it maps your domain to a 128-bit IPv6 address so visitors on IPv6 networks can reach you directly. It behaves like an A record in every other way — same TTL, same propagation — and thanks to Happy Eyeballs fallback, adding one is safe even if some visitors lack IPv6. If your host supports IPv6, publishing an AAAA record alongside your A record is a small step that future-proofs your site as the internet continues its shift to IPv6.
