The A-record is the most basic and the most commonly used DNS record type.
It is used to translate human friendly domain names such as "www.example.com" into IP-addresses such as 23.211.43.53 (machine friendly numbers).
A-records are the DNS server equivalent of the hosts file - a simple domain name to IP-address mapping.
A-records are not required for all computers, but are needed for any computer that provides shared resources on a network.
To create a new A-record, right-click a zone in the left list of DNS Records window, and select "New A-record" from the pop-up menu.
This record type is defined in RFC1035.