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Lesson 2NIS: Network Information System
ObjectiveDescribe the Network Information System.
It is important that every computer on a network has access to certain information. If you use simple configuration files, each host will need exactly the same information at all times. However, for large and dynamic networks, this is simply impractical because the information is complex and constantly changing. The Network Information Server (NIS) solves this problem by maintaining network information in a database on a server. Any client on the network can then access the database for information on hosts, users, passwords, and more.
In order for a client to use NIS, it must be running two daemons. The first daemon, portmap, allows applications running on the NIS client computer to obtain network information from the NIS server. The second daemon, ypbind, is the NIS client daemon itself. The "yp" found in most NIS tool names stands for Yellow Pages(tm), the former name of NIS. You can think of NIS as a similar type of information resource for your network.

NIS network structure
NIS servers store information in databases, sometimes called maps. For example, you can have maps of hostnames to IP addresses, or users to passwords. Each map has a master server. This server is responsible for keeping all information up-to-date and available to clients. You can also set up slave servers, which merely keep an accurate copy of the master's database and handle NIS requests when the master is busy. The Slide Show below explores some different ways NIS networks are organized.

nis server
The next lesson shows you how to obtain information about the network.