|  | 10.2 | The Role of DNS in Router Configurations
| 10.2.4 | How to enable and disable DNS on a router
Each unique IP address can have a host name associated with it. The Cisco IOS software maintains a cache of host name-to-address mappings for use by EXEC commands. This cache speeds the process of converting names to addresses. IP defines a naming scheme that allows a device to be identified by its location in IP. A name such as ftp.cisco.com identifies the domain of the File Transfer Protocol (FTP) for Cisco. To keep track of domain names, IP identifies a name server that manages the name cache. DNS (Domain Name Service) is enabled by default with a server address of 255.255.255.255, which is a local broadcast. The no ip domain-lookup command turns off name-to-address translation in the router. This means that the router will not generate or forward name system broadcast packets.