Network Information Service (NIS), formerly known as Yellow Pages(YP), is a directory service used in intranets to store user databases with password files, host address tables or key codes for Secure Remote Procedure Call( RPC) on a central server and retrieve them from clients.
The NIS concept is hierarchical and works with a master server, where the authoritative information resides, and a slave server, where copies are stored. NIS clients can request information from the master or slave server. The Network Information Service (NIS) implements a network service that provides a distributed database to users on a workstation. This database contains a directory of all available resources on the network, in particular information about passwords, group names, networks and hosts.
One of the best known network management systems is Sun's Network File System( NFS). The NFS system represents a simplification of network management and, by storing passwords and address information centrally, solves the problems associated with distributed access permissions and identifications. With this system, the user no longer has to remember one or more passwords. Like the Network File System (NFS), the NIS system is located on the application layer of the OSI reference model and also uses Remote Procedure Call (RPC) and External Data Representation( XDR) for communication. The Network Information Service is mainly supported by Unix systems.