Developers at Sun Microsystems realized that the “edit one file per machine” approach endemic to host files didn’t scale, so they invented something called Yellow Pages (YP). Yellow Pages was designed to distribute all the network-wide configuration file information found in files like /etc/hosts, /etc/passwd, /etc/services, etc. In this chapter, we’ll concentrate on its use as a network name service to distribute the machine name-to-IP address mapping information.

YP was renamed Network Information Service, or NIS, in 1990, shortly after British Telecom asserted (with lawyers) that it held the trademark for “Yellow Pages” in the U.K. The ghost of the name “Yellow Pages” still haunts many a Unix box today in the names used for NIS commands and library calls (e.g., ypcat, ypmatch, yppush). All modern Unix variants support NIS. NT machines can be made to use NIS for authentication through the use of special home-brewed authentication libraries,[14] but I know of no NT-based NIS servers. I do not know of any Mac ports of NIS.

In NIS, an administrator designates one or more machines as servers from which other machines will receive client services. One server is the master server, the others slave servers. The master server holds the master copies of the actual text files (e.g., /etc/hosts or /etc/passwd ) all machines normally use. Changes to these files take place on the master and are then propagated to the slave servers.

Any machine on the network that needs ...

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