A name service which associates domain names with IP addresses. It replaced an original scheme in which this information was held in a central database and downloaded to computers using the File Transfer Protocol. It is set up as a number of name servers spread throughout the Internet partitioned into zones. Each server receives requests for addresses and either resolves them when the information required can be found on its database or sends a request on to another server administering a different zone. This service is one of the most frequently used on the Internet, as whenever a symbolic domain name is employed, for example in an email address, the service needs to be consulted.