GNU/Linux Desktop Survival Guide
by Graham Williams
NIS is used to share password files among a collection of machines. This ensures all users have access to all machines and have the same user id and group ids. The group of machines is referred to with a domain name (nothing to do with a network domain name though). One machine in the group must be a master server and the rest are nis clients of that server. You can also have slave servers but we'll ignore that one for now.