What is an AAAA record?
An AAAA record — commonly called a quad-A record — is a DNS (Domain Name System) entry that maps a domain name to its corresponding IPv6 address. It serves the same purpose as an A record, but for the newer, larger IPv6 address space rather than the older IPv4 format.
IPv6 addresses are 128 bits long, compared to the 32 bits used by IPv4. That makes an AAAA record four times the size of an A record — which is exactly where the "quad A" name comes from. A typical IPv6 address looks like 2001:0db8:85a3:0000:0000:8a2e:0370:7334, written as eight groups of four hexadecimal digits separated by colons.
Why are AAAA records important?
The IPv4 address space, with roughly 4.3 billion possible addresses, has been exhausted. IPv6 expands that pool to an almost unfathomably large number — approximately 340 undecillion unique addresses — ensuring the internet can continue growing for the foreseeable future. As more devices connect to the internet and more networks transition to IPv6, AAAA records are becoming increasingly essential for any domain that wants to remain reachable to all users.
Modern operating systems and browsers prefer IPv6 when it is available. If a domain has a AAAA record and the user's ISP supports IPv6, the connection will typically be made over IPv6 automatically. Having both an A and a AAAA record configured ensures a domain is accessible to clients on either protocol.
How to use the AAAA record lookup tool
Enter any domain or subdomain in the search field — no need to include https:// — and click Lookup. The tool queries DNS in real time and returns any AAAA records associated with that domain within seconds.
Each result shows the host name, the full IPv6 address it resolves to, and the TTL (Time to Live) value. If no AAAA records are returned, the domain is likely configured for IPv4 only and you can use the A Record Lookup tool instead.
Understanding the results
The Host column shows the fully qualified domain name the record belongs to. The IPv6 Address column contains the full AAAA record value — the IPv6 address the domain resolves to. The TTL value shows how long, in seconds, DNS resolvers should cache this record before fetching a fresh copy from the authoritative name server.
As with A records, a shorter TTL means DNS changes will propagate faster globally. A longer TTL reduces repeated DNS lookups at the cost of slower propagation when the record is updated. Lowering the TTL before making planned DNS changes is a good practice to limit disruption.
Frequently Asked Questions
Can a domain have both an A record and an AAAA record?
Yes, and this is actually recommended for most public-facing domains. Having both means your domain is reachable over IPv4 and IPv6 simultaneously. When a visitor's device and network support IPv6, the connection will typically prefer the AAAA record. If IPv6 is unavailable, the browser falls back to the A record and IPv4 seamlessly. Running both records in parallel is known as dual-stack configuration.
How do I know if a domain supports IPv6?
Run an AAAA record lookup for the domain. If one or more AAAA records are returned with valid IPv6 addresses, the domain has IPv6 support configured. If the lookup returns no records or an error, the domain is currently IPv4-only. You can also try prefixing the domain with www. if the bare domain returns no results, as some subdomains are configured separately.
What is the difference between an A record and an AAAA record?
Both record types map a domain name to an IP address, but they handle different IP versions. A records map to IPv4 addresses (32-bit, written as four decimal groups like 192.168.1.1). AAAA records map to IPv6 addresses (128-bit, written as eight hexadecimal groups like 2001:db8::1). The core function is identical — the difference is purely in which addressing scheme the record supports.
Why might an AAAA lookup return no results?
A domain will return no AAAA records if its DNS zone has not been configured with any IPv6 addresses. This is common for older websites or hosting environments that have not yet adopted IPv6. It does not mean the domain is broken — it simply means the domain operates on IPv4 only. You can verify IPv4 connectivity by running an A record lookup for the same domain.
Do AAAA records affect website performance?
In most cases, IPv6 connections perform comparably to IPv4 and can sometimes be faster depending on network routing. Modern browsers implement a mechanism called Happy Eyeballs, which races IPv4 and IPv6 connection attempts simultaneously and uses whichever completes first. This means having a AAAA record should not slow down your site for anyone — IPv4 users are unaffected, while IPv6 users benefit from the native connection.
How long does it take for AAAA record changes to propagate?
Propagation time depends on the TTL value set on the record before the change was made. If the TTL was 3600 seconds (one hour), it can take up to an hour for all resolvers globally to clear their cached copy and fetch the updated record. Reducing the TTL to a lower value (such as 300 seconds) ahead of a planned change can significantly shorten this window. Full propagation typically completes within a few minutes to a few hours for most users.