The Domain Name System (DNS) associates various information with domain names; most importantly, it serves as the "phone book" for the Internet by translating human-readable computer hostnames, e.g. www.webfitz.com, into an Internet Protocol (IP ) address, i.e. 123.456.456.166, that networking equipment needs to deliver information.  It also stores other information such as the list of mail exchange servers (MX records) that accept email for a given domain.  In providing a worldwide keyword-based redirection service, the Domain Name System is an essential component of Internet use.