A domain name server is a computer that has records of domain names and its web server’s IP address.
For example, when a user enters the domain name in a browser to go to a website, your browser looks up the IP address in the DNS for web server assigned to the domain name. The computer then sends the request to the IP address for a resource. e.g http://www.waterloowebservices.com
As a user, we use the domain name instead of the IP addresses of a web server because names are easier to remember than numbers. Technically, we can use the IP address instead. The domain name servers mitigate remembering the IP address of a website.