NIS Domain

An NIS domain is a collection of systems that are logically grouped together.

A group of hosts that share the same set of NIS maps belong to the same domain. The hosts are usually grouped together in the domain for a common reason; for example, when working in the same group at a particular location. Each NIS host is assigned to a domain when the system starts. The domain name must be set on all hosts that intend to use NIS.

There is one master server per NIS domain, and the systems in the domain are typically on the same network. However, access to data served by NIS is independent of the relative locations of an NIS client and server. All systems within the NIS domain use the master server to retrieve system information, and the number of systems in a domain must be limited for the sake of efficiency. As the number of systems grows, the response time from the master server increases because of the increased workload. By design, you cannot add another master server to a domain because there would be two authoritative sources for the maps. To reduce master server load, you can add worker servers to the domain, or define more than one domain. Each new domain, of course, has its own master server.