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What Is an AAAA Record?

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What is an AAAA record?

An AAAA record (record type 28) does the same job as an A record, except it points to IPv6 addresses instead of IPv4. It connects a domain name like api.example.com to the IPv6 address of the server that hosts it.

If you know how A records work, AAAA records are pretty similar. A records point to IPv4 addresses. AAAA records point to IPv6 addresses. Same concept, different address format.

IPv6 adoption and AAAA records

We’ve been running out of IPv4 addresses for a while now. That’s why more of the internet is moving to IPv6 (Internet Protocol Version 6). IPv6 gives us way more addresses to work with, plus some improvements to how the internet works.

As more networks and devices support IPv6, AAAA records are getting more common. All of DNSimple’s name servers, which serve DNS hosting at DNSimple, have IPv6 addresses, so they can handle queries over IPv4 or IPv6. This dual-stack setup means they work with either protocol.

How AAAA records work

Here’s what happens when your device tries to reach a domain. If your device and network support IPv6, it usually asks for both the AAAA and the A records. If it gets an IPv6 address, it generally prefers to connect over IPv6, and falls back to IPv4 if that connection fails or is slow (RFC 8305). If there is no AAAA record, it connects over IPv4.

You don’t have to pick one or the other. You can set up both A and AAAA records on the same domain. That way, clients can connect using whichever protocol they support.

Common uses for AAAA records

AAAA records work just like A records, but for IPv6:

Hosting services over IPv6: Use AAAA records to make your website, email server, or other services reachable over IPv6.

Redundancy and load balancing: You can create multiple AAAA records for the same domain, each pointing to a different server’s IPv6 address. This lets you do a couple of things:

  • Load balancing: Resolvers and browsers spread requests across the addresses, so traffic is shared between servers.
  • Basic redundancy: Many clients try another address if the first one does not respond. DNS keeps returning every address, though, including one whose server is down, so this is not health-checked failover.

Multiple domains, one address: Different domain names can all point to the same IPv6 address. Each domain gets its own AAAA record, but they all resolve to that shared IP.

The technical details are in RFC 3596, Section 2.1 if you want to dig into the specification.

Managing AAAA records in DNSimple

You can manage AAAA records using DNSimple’s record editor. Add new ones, remove old ones, or update IPv6 addresses as needed.

For detailed steps, check out our guide: Manage AAAA Records.

Have more questions?

If you have additional questions or need any assistance with AAAA records, just contact support, and we’ll be happy to help.