What is a DNS A record?

DNS A records associate hostnames to IP addresses of hosts (computers) on the Internet. The hostname can be a root domain (such as example.com), or a sub-domain (like www.example.com). Each hostname can also have more than one DNS A record, thus acting as a DNS level load-balancer for the hosts.

Input required to set DNS A records

DNS A record requires three inputs:

1. Name: This is the DNS name of a hostname. For example, the DNS name will be "www" for the hostname "www.example.com". To set up a DNS record for the root domain “example.com“, this field can be left empty or the symbol ‘@’ used instead. The DNS name must follow the limits defined in RFC1035,
   i. DNS name can have up to 250 characters, and must start with a letter (a-z), end with a letter or a digit (0-9), and can have only letters, digits, and hyphen (-) as characters.
   ii. DNS name can be split into labels using the dot (.) character, to a maximum of 8 labels. Each label can have 63 characters or less.
2. Data: For the DNS A record, the data (target) is the IPv4 address of the host/computer on the Internet.
3. TTL: TTL or Time To Live is the time-span limit (in seconds) for the DNS data on the Internet. DNS caching servers use this limit while saving the record temporarily for faster DNS resolution.

Usage scope for DNS A records

DNS A records can map IPv4 addresses only, whereas the DNS AAAA records map IPv6 addresses. For example, "93.184.216.34" is the IPv4 address of "example.com" hosted using a DNS A record. Also, certain IPv4 addresses like private addresses (such as 0.0.0.0) cannot be hosted using DNS A records, but only those address ranges accessible on the Internet.

How to host a DNS A record

DNS records are hosted on the Internet through DNS hosting services. If you are using SlickAlpha DNS, check this related guide to learn how to add a DNS record on your SlickAlpha account.

How to check DNS A records

DNS records can be queried directly on your system terminal using the dig command. To check your DNS A records on the browser, try our free DNS Lookup tool.

Uses of DNS A records

DNS A record is essential in mapping domains and sub-domains to IP addresses of host computers. The most common use of DNS A record is web browsing. When the hostname is entered on a web browser, the browser client uses the DNS A record to get the IP address of the host from public DNS resolvers. The browser then connects the host server using that IP address to fetch web content. DNS lists also use DNS A records to provide domain-related information.