On the Internet, the domain name stores and associates many types of information with domain names; most importantly, it translates domain names (computer hostnames) to IP addresses. It also lists mail exchange servers accepting e-mail for each domain. In providing a worldwide keyword-based redirection service, DNS is an essential component of contemporary Internet use.

Useful for several reasons, the domain name pre-eminently makes it possible to attach easy-to-remember domain names (such as "ec2biz.com") to hard-to-remember IP addresses (such as 202.123.84.161). People take advantage of this when they recite URLs and e-mail addresses. In a subsidiary function, the domain name system makes it possible for people to assign authoritative names without needing to communicate with a central registrar each time.