What do DNS A and AAAA records show?¶
title: "What do DNS A and AAAA records show?" card_id: "IP-038" status: "complete" source_document: "https://docs.google.com/document/d/155m-HCVyFW8tgepVjpabiEK6XA2PeV8FlPbWE0Xtlkg/edit?usp=drivesdk"
What do DNS A and AAAA records show?¶
Two of the most common DNS record types are A records and AAAA records.
They perform essentially the same job for different versions of IP addressing.
An A record associates a domain name or hostname with an IPv4 address.
For example, a DNS response might show:
ifdigital.co.uk has an A record pointing to 203.0.113.25.
That tells a device that the IPv4 address can be used when attempting to contact the named service.
A AAAA record—usually pronounced “quad A”—associates the name with an IPv6 address.
For example:
ifdigital.co.uk has a AAAA record pointing to 2001 colon db8 double colon 25.
A domain can have an A record, a AAAA record or both.
A device capable of using both IPv4 and IPv6 may receive both types of answer and decide which connection to attempt.
A name can also have several A or AAAA records at the same time.
The service may use several servers, distribute traffic between different locations or use a content-delivery network. Different users may therefore receive different addresses for the same name.
The records can also change.
A service may move to another hosting provider, replace a server or alter its network configuration. A DNS lookup performed today doesn't necessarily show which address was associated with the name at the time of an earlier event.
The absence of an A record doesn't necessarily mean the domain has no service.
It might use IPv6 only, provide an alias through another DNS record or use the particular name for something other than a website.
An A or AAAA record establishes a published technical association between a name and an IP address.
It doesn't prove that the organisation controlling the domain owns the physical server at that address. The address may belong to a hosting provider, cloud platform, reverse proxy or content-delivery network.
It also doesn't prove that the IP address is used exclusively by that domain. Several unrelated names may share the same address.
Most importantly, the record doesn't show that a particular person visited the domain or connected to the address.
A and AAAA records provide destinations that devices may use. They describe how a name can be reached—not who reached it or what subsequently happened.