AAAA Record
A DNS AAAA record (pronounced 'quad-A') maps a domain name to an IPv6 address. DNS AAAA records are exactly like DNS A records, except that they store a domain's IPv6 address instead of its IPv4 address. IPv6 uses 128-bit IP addresses, providing a near-infinite IP capacity compared to the limited IPv4 address space.
How it works
AAAA records work identically to A records, but they point to IPv6 addresses instead of IPv4 addresses. When a device attempts to connect to a domain, its DNS resolver will typically try to find an AAAA record first if the device and network support IPv6.
The user's device sends a DNS query for the domain's AAAA record to a recursive DNS resolver. The resolver queries the authoritative nameservers for the domain. If an AAAA record exists for the domain, the authoritative nameserver responds with the associated IPv6 address. The resolver caches the response and returns the IPv6 address to the user's device. The user's device can now establish a connection to the resource using the provided IPv6 address.
Key Points
- AAAA records store IPv6 addresses in the format
2606:2800:21f:cb07:6820:80da:af6b:8b2c - IPv6 uses 128-bit IP addresses, offering up to 340 undecillion unique addresses
- If an AAAA record is not found, the DNS resolver will fall back to looking for an
A record and connecting over IPv4 - You can run both A and AAAA records simultaneously for maximum compatibility
- The adoption of IPv6 is steadily increasing worldwide due to IPv4 address exhaustion
Common Use Cases
- IPv6-Only Networks: Essential for devices and networks that operate exclusively on IPv6, including many modern cellular networks
- Future-Proofing: Preparing your infrastructure for the inevitable transition from IPv4 to IPv6 as IPv4 addresses become scarce
- Dual-Stack Configuration: Running both A and AAAA records to support both IPv4 and IPv6 clients, ensuring universal accessibility
- Modern Mobile Networks: Supporting IPv6 users on cellular networks where IPv6 is increasingly the default protocol
code Example Configuration
| Type | Host / Name | Value / Points to | TTL |
|---|---|---|---|
| AAAA | @ | 2606:2800:21f:cb07:6820:80da:af6b:8b2c | 3600 |
| AAAA | www | 2606:2800:21f:cb07:6820:80da:af6b:8b2c | 3600 |
| A | @ | 192.0.2.1 | 3600 |
* IPv6 addresses are much longer than IPv4 addresses and use hexadecimal notation separated by colons.
Frequently Asked Questions
What is the difference between A and AAAA records?expand_more
Both record types serve the same purpose - mapping a domain name to an IP address. The only difference is that A records map to IPv4 addresses (32-bit, format like
192.0.2.1), while AAAA records map to IPv6 addresses (128-bit, format like 2606:2800:21f:cb07:6820:80da:af6b:8b2c).Why is it called AAAA (quad-A)?expand_more
It's called AAAA because IPv6 addresses are four times larger than IPv4 addresses (128 bits vs 32 bits). The four As represent this quadruple size, even though the actual record type is technically just 'AAAA'.
Do I need both A and AAAA records?expand_more
For maximum compatibility, it's recommended to have both. Many users still access the internet via IPv4, so an A record ensures they can reach your site. However, adding an AAAA record future-proofs your domain and serves the growing number of IPv6-only users, especially on mobile networks.
Will DNS automatically prefer IPv6 over IPv4?expand_more
Most modern devices and operating systems prefer IPv6 when available. If both A and AAAA records exist, and the client supports IPv6, the device will typically attempt to connect via IPv6 first. If that fails, it will fall back to IPv4.
Is IPv6 faster than IPv4?expand_more
IPv6 itself isn't inherently faster, but it can provide performance benefits by eliminating the need for NAT (Network Address Translation) and enabling more efficient routing. In practice, the speed difference is usually negligible for most users.