2. Glossary and General Information

2.1. Glossary of Terms

In this document a lot of acronyms are used. Here are the most important acronyms and a brief explanation:

DBM: DataBase Management, a library of functions which maintain key-content pairs in a data base.
DLL: Dynamically Linked Library, a library linked to an executable program at run-time.
domainname: A name "key" that is used by NIS clients to be able to locate a suitable NIS server that serves that domainname key. Please note that this does not necessarily have anything at all to do with the DNS "domain" (machine name) of the machine(s).
FTP: File Transfer Protocol, a protocol used to transfer files between two computers.
libnsl: Name services library, a library of name service calls (getpwnam, getservbyname, etc...) on SVR4 Unixes. GNU libc uses this for the NIS (YP) and NIS+ functions.
libsocket: Socket services library, a library for the socket service calls (socket, bind, listen, etc...) on SVR4 Unixes.
NIS: Network Information Service, a service that provides information, that has to be known throughout the network, to all machines on the network. There is support for NIS in Linux's standard libc library, which in the following text is referred to as "traditional NIS".
NIS+: Network Information Service (Plus :-), essentially NIS on steroids. NIS+ is designed by Sun Microsystems Inc. as a replacement for NIS with better security and better handling of _large_ installations.
NYS: This is the name of a project and stands for NIS+, YP and Switch and is managed by Peter Eriksson <peter@ifm.liu.se>. It contains among other things a complete reimplementation of the NIS (= YP) code that uses the Name Services Switch functionality of the NYS library.
NSS: Name Service Switch. The /etc/nsswitch.conf file determines the order of lookups performed when a certain piece of information is requested.
RPC: Remote Procedure Call. RPC routines allow C programs to make procedure calls on other machines across the network. When people talk about RPC they most often mean the Sun RPC variant.
YP: Yellow Pages(tm), a registered trademark in the UK of British Telecom plc.
TCP-IP: Transmission Control Protocol/Internet Protocol. It is the data communication protocol most often used on Unix machines.

2.2. Some General Information

The next four lines are quoted from the Sun(tm) System & Network Administration Manual:

    "NIS was formerly known as Sun Yellow Pages (YP) but
     the name Yellow Pages(tm) is a registered trademark
     in the United Kingdom of British Telecom plc and may
     not be used without permission."

NIS stands for Network Information Service. Its purpose is to provide information, that has to be known throughout the network, to all machines on the network. Information likely to be distributed by NIS is:

login names/passwords/home directories (/etc/passwd)
group information (/etc/group)

If, for example, your password entry is recorded in the NIS passwd database, you will be able to login on all machines on the network which have the NIS client programs running.

Sun is a trademark of Sun Microsystems, Inc. licensed to SunSoft, Inc.