Network Interfaces; Network Configuration Files; Interface Configuration Files - Red Hat ENTERPRISE LINUX 3 Reference Manual

Under Red Hat Enterprise 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/
interface files can differ from system to system, there are three categories of files that exist in this
directory:
Interface configuration files
•
Interface control scripts
•
Network function files
•
The files in each of these categories work together to enable various network devices.
This chapter explores the relationship between these files and how they are used.
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 Enterprise Linux system.
The primary network configuration files are as follows:
— The main purpose of this file is to resolve hostnames that cannot be resolved any
• /etc/hosts
other way. It can also be used to resolve hostnames on small networks with no DNS server. Re-
gardless of the type of network the computer is on, this file should contain a line specifying the IP
address of the loopback device (
tion, refer to the
hosts
•
/etc/resolv.conf
Unless configured to do otherwise, the network initialization scripts populate this file. For more
information about this file, refer to the
• /etc/sysconfig/network
For more information about this file and the directives it accepts, refer to Section 4.1.22
/etc/sysconfig/network
• /etc/sysconfig/network-scripts/ifcfg- interface-name
terface, there is a corresponding interface configuration script. Each of these files provide informa-
tion specific to a particular network interface. Refer to Section 8.2 Interface Configuration Files for
more information on this type of file and the directives it accepts.
Caution
The
/etc/sysconfig/networking/
(
redhat-config-network
about configuring network interfaces using the Network Administration Tool, refer to the chapter
called Network Configuration in the Red Hat Enterprise Linux System Administration Guide.
127.0.0.1
man page.
— This file specifies the IP addresses of DNS servers and the search domain.
resolv.conf
— Specifies routing and host information for all network interfaces.
.
directory is used by the Network Administration Tool
) and its contents should not be edited manually. For more information

Network Interfaces

directory. Although the number and type of
) as
localhost.localdomain
man page.
Chapter 8.
. For more informa-
— For each network in-