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A record and AAAA record – Comparison


DNS records are small but very important elements for the Domain Name System (DNS) to operate properly. There are different DNS records to accomplish specific functions. The A record and AAAA record are essential to translate domain names to IP addresses. Yes, you got it! Without them, the Internet experience wouldn’t be as comfortable as it is now.

What is the purpose of the A and AAAA records? – Quick review

The A and AAAA records are very important to access domain names. Both DNS records are directly involved in the DNS resolution process. When a user requests a domain name, this action triggers a process to search for the corresponding IP address of the requested domain. Without the IP address, the content of the domain can’t be loaded.

For instance, a user requests, so the resolution process gets triggered until it gets its corresponding IP address At that moment, the domain is loaded so the user can access it.

And this key process is driven exactly by the A record and the AAAA record.

A record and AAAA record, comparison

A and AAAA records are used for the same purpose, to point a domain name to its associated IP address. The big difference is that an A record points to an IPv4 address. Meanwhile, an AAAA record points to an IPv6 address. This last is the latest IP version, which is expected to dominate the Internet in the future.

The IPv4 structure is a 32-bit number. You will find it written in decimal digits, with four 8-bit fields divided by periods (.). Every 8-bit field represents a byte. Example:

The IPv6 structure includes eight fields of four hexadecimal digits divided by colons (:). Every field represents 16 bits. Example: 2011:0db6:67a2:0300:0000:7a1e:0256:7662

One big advantage of an AAAA record is that it can save a 128-bit IPv6 address. In contrast, an A record can store only a 32-bit IPv4 address.

Availability is another difference to consider between the A and the AAAA records. Remember that the world ran out of IPv4 addresses a time ago. You can still find some, but it’s getting harder every day. This was exactly what motivated the creation of IPv6. The A records were more used due to the IPv4 popularity. But this situation is predicted to change once the IPv6 and its corresponding AAAA record get more used.

Remember that since the early 1990s, with the huge Internet growth, the world faced the need for a successor for IPv4. The number of devices requesting Internet connection increased massively, and networks had to optimize the administration of the available IPv4 addresses to the maximum. Then IPv6 got born, and it’s available since 1999. But still, now, the transition is ongoing. Now more devices support IPv6, the problems of compatibility have been solved slowly, and still, it will take a bit more to accomplish the transition completely.


The A and AAAA records are small technology with a huge responsibility! The DNS and the Internet couldn’t work without them.

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