Linux in a Nutshell, Fifth Edition

Overview of Networking | 19

Sys Admin

Overview

This is the Title of the Book, eMatter Edition

Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

Miscellaneous

Overview of Networking

Networks connect computers so that the different systems can share information.

For users and system administrators, Unix systems have traditionally provided a

set of simple but valuable network services that let you check whether systems are

running, refer to files residing on remote systems, communicate via electronic

mail, and so on.

For most commands to work over a network, each system must be continuously

running a server process in the background, silently waiting to handle the user’s

request. This kind of process is called a daemon. Common examples, on which

you rely for the most basic functions of your Linux system, are named (which

translates between numeric IP addresses and more human-readable alphanumeric

names), cupsd (which sends documents to a printer, possibly over a network),

and ftpd (which allows connections via ftp).

Most Unix networking commands are based on Internet protocols, standardized

ways of communicating across a network on hierarchical layers. The protocols

range from addressing and packet routing at a relatively low layer to finding users

and executing user commands at a higher layer.

The basic user commands that most systems support over Internet protocols are

generally called ...