Linux Network Administrator's Guide, 3rd Edition

Chapter 2. Issues of TCP/IP Networking

In this chapter we turn to the configuration decisions that you’ll need to make when connecting your Linux machine to a TCP/IP network, including dealing with IP addresses, hostnames, and routing issues. This chapter gives you the background you need in order to understand what your setup requires, while the next chapters cover the tools that you will use.

To learn more about TCP/IP and the reasons behind it, refer to the three-volume set Internetworking with TCP/IP (Prentice Hall) by Douglas R. Comer. For a more detailed guide to managing a TCP/IP network, see TCP/IP Network Administration (O’Reilly) by Craig Hunt.

Networking Interfaces

To hide the diversity of equipment that may be used in a networking environment, TCP/IP defines an abstract interface through which the hardware is accessed. This interface offers a set of operations that is the same for all types of hardware and basically deals with sending and receiving packets.

For each peripheral networking device, a corresponding interface has to be present in the kernel. For example, Ethernet interfaces in Linux are called by such names as eth0 and eth1; PPP (discussed in Chapter 6) interfaces are named ppp0 and ppp1; and FDDI interfaces are given names such as fddi0 and fddi1. These interface names are used for configuration purposes when you want to specify a particular physical device in a configuration command, and they have no meaning beyond this use.

Before being used by TCP/IP ...