A record

An A record is a DNS record that gives an IPv4 address for a name. IPv4 is the familiar Internet Protocol version whose addresses are written as four numbers separated by dots, such as 192.0.2.25. When a device looks up a name and requests its A record, DNS can return the address that the name is configured to use.

What does an A record do?

An A record helps a program find an IPv4 destination for a domain name or host name. For example, a website owner might configure an A record for www.example.com with the address 192.0.2.25. A browser can use the DNS answer to learn which address to contact, then make a separate web request to that server.

The example address is reserved for documentation; it does not identify a real public website. In an actual setup, the value must be an IPv4 address supplied or configured for the service. If a hosting provider changes the server address, the owner may need to update the A record. Until temporarily saved DNS answers expire, some users may continue to receive the earlier address.

Is an A record the same as an AAAA record?

No. An A record stores an IPv4 address. An AAAA record stores an IPv6 address, the newer IP format with many more possible addresses. A domain can have both record types so that clients using either network protocol can find a suitable address. The protocol used to ask DNS is independent of whether the requested answer is IPv4 or IPv6.

An A record only supplies address information. It does not contain the website or confirm that a server is online. For the general structure of DNS entries, see DNS records.

Related terms

• DNS record — the broader kind of information an A record belongs to
• AAAA record — the record type for an IPv6 address
• IPv4 and IPv6 — explains the two IP versions