What Is A DNS A Record?

100% Uptime SLA, 24/7/365 Live Support & Fast Cloud Servers

The 'A' stands for 'address' and this is the most basic kind of DNS record: the IP address of a given domain is indicated. For instance, if you pull cloudflare.com DNS records, the A record currently returns an IP address of 104.17.210.9.

A records only hold IPv4 addresses. If a website has an IPv6 address, it will instead use an ‘AAAA’ record.

Here is an example of an A record:

example.com record type: value: TTL

@ A 192.0.2.1 14400

In this example, the '@' symbol indicates that this is a record for the root domain, and the TTL (time to live), specified in seconds, is the '14400' value. For A records, the default TTL is 14400 seconds. This implies that it takes 240 minutes (14400 seconds) to take effect if an A record gets changed.

There is only one A record for the vast majority of websites, although it is possible to have many. As part of a technique called round-robin load balancing, some higher profile websites may have several distinct A records, which can disperse request traffic to one of several IP addresses, each hosting identical content.

When are DNS A records used?

IP address lookups are the most popular use of A records: matching a domain name (like 'cloudflare.com') to an IPv4 address. This allows the computer of a user to connect to and load a website without memorising and typing in the actual IP address by the user. This is automatically carried out by the user's web browser by submitting a question to a DNS resolver.

For running a Domain Name System-based Blackhole List (DNSBL), DNS A records are also used. Mail servers may be supported by DNSBLs to recognise and block email messages from suspected spammers.

Registered in England and Wales with company number 12201331.

Registered Office: 252 High Street, Aldershot, 
United Kingdom, GU12 4LP
cloud-syncearthbullhorn