The domain name system or domain name server (DNS) is a system that stores information associated with domain names in a distributed database on networks, such as the Internet. The domain name system (domain name server) associates many types of information with domain names, but most importantly, it translates the domain name (computer hostnames) to IP addresses. It is used to store DNS records such as MX(Mail exchange) records, C (Canonical)records and A(Aliases) records.
DNS is useful for several reasons. Most well known, the DNS makes it possible to attach easy-to-remember domain names and hard-to-remember IP addresses. For example 220.127.116.11 is one ip address of Google.com. It is very difficult to remember always so you can use domain name to view the particular website.The primary work of DNS is, if you give ip address in the browser ,it search for the domain name of a particular ip address. If you give domain name in the address bar of the browser it convert the domain name to ip address(Search for the particular ip address). For any queries regarding DNS visit the site WhoisXY.com