Chapter 8. Network Interfaces
Under Red Hat Linux, all network communications occur between configured software
interfaces and physical networking devices
connected to the system.
The configuration files for network interfaces, and the scripts to activate
and deactivate them, are located in the
/etc/sysconfig/network-scripts/ directory. Although
the number and type of interface files can differ from system to system,
there are three categories of files that exist in this directory:
The files in each of these categories work together to enable various
network devices under Red Hat Linux.
This chapter will explore the relationship between these files and how they
8.1. Network Configuration Files
Before delving into the interface configuration files, let us first
itemize the primary configuration files used in network
configuration. Understanding the role these files play in setting up the
network stack can be helpful when customizing a Red Hat Linux system.
The primary network configuration files are as follows:
/etc/hosts — The main purpose of this
file is to resolve hostnames that cannot be resolved any other way. It
can also be used to resolve hostnames on small networks with no DNS
server. Regardless of the type of network the computer is on, this file
should contain a line specifying the IP address of the loopback device
localhost.localdomain. For more information, see the
hosts man page.
/etc/resolv.conf — This file
specifies the IP addresses of DNS servers and the search
domain. Unless configured to do otherwise, the network
initialization scripts populate this file. For more information on
this file, see the resolv.conf man page.
/etc/sysconfig/network — Specifies
routing and host information for all network interfaces. For more
information on this file and the directives it accepts, see Section 4.1.23 /etc/sysconfig/network.
— For each network interface on a Red Hat Linux system, there is a
corresponding interface configuration script. Each of these files
provide information specific to a particular network interface. See
Section 8.2 Interface Configuration Files for more information on
this type of file and the directives it accepts.
The /etc/sysconfig/networking/ directory is used
by the Network Administration Tool
(redhat-config-network) and its contents should not
be edited manually. For more information about configuring network
interfaces using the Network Administration Tool, see
the chapter called Network Configuration in the
Red Hat Linux Customization Guide.