NIS - Network Information System

have NIS domains (not related to DNS domains).
machines in a domain share configuration information.
for a domain, NIS server machines keep the information, and other machines send requests to them when they need it. E.g., when looking up a password entry.
a domain has one master server which has the canonical version of the information, and slave servers which have copies of the information.
the information is stored in maps, which are dbm format key/value databases.

netgroup is a logical grouping of users or hosts.
not related to unix groups.
used for controlling access. E.g., putting a number of users in the foo netgroup and adding +@foo to the password file of a machine gives those users login access to that machine.

Linux can easily be an NIS client.
support for the NIS lookups is build into libc.
need the ypclients-2.1.tar.gz clients.
Can be a master, but support is not as complete, and you will need a different C library. See the NIS HOWTO.

modify your /etc/rc.* boot files
- add domainname `cat /etc/defaultdomain` to rc.net1 after the hostname setting line.
- add ypbind to rc.net2 after the lines which run portmap and inetd.
edit /etc/defaultdomain to contain your NIS domainname.
mkdir /var/yp
add + entries to /etc/passwd, /etc/group
add nis to /etc/host.conf to support nis host lookups. E.g.: order hosts, bind, nis

for informational purposes - most NIS operation is hidden away in the library calls.
ypcat: show a map. E.g., ypcat passwd
ypmatch: match a key in a map. E.g., ypmatch username passwd
ypwhich: show which NIS server we are bound to.