Abbreviated as NIS, Network Information Service
is a client-server directory service protocol
for distributing system configuration data such as user and host names between computers on a computer
network. NIS allows a group of machines within an NIS domain to share a common set of configuration files. This permits a system administrator to set up NIS client systems with only minimal configuration data and add, remove or modify configuration data from a single location. NIS was first developed by Sun Microsystems to centralize administration of SunOS systems. Now, NIS is supported by all major Unix-based systems including Solaris, HP-UX, AIX, Linux, NetBSD, OpenBSD, and others.