Linux Networking Clearly Explained - lions-wing.net

CHAPTER 1 • CREATING A DIAL-UP INTERNET CONNECTION 37
Now you are ready to move on to Chapter 2, where you
will configure Netscape Communicator on your Linux
system. If you would like to learn more about the technical
side of PPP connections with Linux, read the next
section.
Looking Under the Hood
This section briefly introduces the technology that underlies
PPP connections with Linux; in addition, it discusses
some text-mode commands that you may wish to try. You
do not need to have this information down cold to use
Linux successfully; it is of interest only if you would like
to learn more about how Linux works.
The PPP Network Interface (ppp0)
The PPP Daemon
To connect your Linux system to the Internet, it is necessary
to define a network interface. In brief, a network
interface is a file that serves as an intermediary between a
networking device, such as an Ethernet adapter or a
modem, and the Linux kernel. When you connect to the
Internet by means of a modem, the PPP software detects
your modem and creates a network interface called ppp0.
If your computer were equipped with more than one
modem, the software would create additional interfaces
(ppp1, ppp2, and so on).
To implement PPP connections, Linux distributions make
use of the pppd daemon (a daemon is a program that runs
in the background, waiting to step into action when its
services are needed). A pppd is not meant to be run manually;
rather, it is launched by other programs. Among