The Network Information Service (NIS) is a system that provides network information (login names,
passwords, home directories, group information) to all of the machines on a network. NIS can allow
users to log in on any machine on the network, as long as the machine has the NIS client programs
running and the user’s password is recorded inthe NIS passwd database. NIS was formerly known as
Sun Yellow Pages(YP). This package provides the ypbind daemon. The ypbind daemon binds NIS
clients to an NIS domain. Ypbind must be running on any machines running NIS client programs.
Install the ypbind package on any machines running NIS client programs (included in the yp?tools
package). If you need an NIS server, youalso need to install the ypserv package to a machine on your
network.

Sumber : http://www.tldp.org/LDP/Linux?Dictionary/html/index.html