"Welcome back, everyone, to another episode of the SysAdmin's
Corner, where we discuss all things Linux, dig deep below the
surface of our systems and really get to know the soul of the
machine itself. <insert appropriate mood music here> When
last we met on this very corner, we were mucking about with file
sharing, specifically NFS. As you all noticed, NFS has some rather
annoying problems when it comes to permissions. The most annoying
thing about NFS is it assumes a user's name and UID on one machine
matches exactly the user's name and UID on another machine, which
means you either have to have matching password and group files on
all your servers or, somehow, anonymous access is sufficient for
all your needs."
"The answer to this problem is NIS (well, one answer, anyhow).
NIS allows us to share databases of critical system information
across our network, information like users, groups, e-mail aliases
and other things, without having to maintain that information on
every server. Like NFS, NIS is a child of Sun Microsystems and,
also like NFS, goes back to the 1980s. At that time, it was called
Yellow Pages, but since Yellow Pages happens to be a registered
trademark, the name was changed to avoid legal troubles.
Nevertheless, the echoes of those YP days is still with us when we
deal with NIS. As you will soon discover during this section, the
letters "yp" show up in configuration files and commands