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10.3. Configuring a DHCP Client

The first step for configuring a DHCP client is to make sure the kernel recognizes the network interface card. Most cards are recognized during the installation process and the system is configured to use the correct kernel module for the card. If a card is added after installation, Kudzu [7] will recognize it and prompt you for the proper kernel module (Be sure to check the Hardware Compatibility List at http://hardware.redhat.com/hcl/). If either the installation program or kudzu does not recognize the network card, you can load the correct kernel module (refer to Chapter 30, General Parameters and Modules for details).
To configure a DHCP client manually, modify the /etc/sysconfig/network file to enable networking and the configuration file for each network device in the /etc/sysconfig/network-scripts directory. In this directory, each device should have a configuration file named ifcfg-eth0, where eth0 is the network device name.
The /etc/sysconfig/network file should contain the following line:
NETWORKING=yes
The NETWORKING variable must be set to yes if you want networking to start at boot time.
The /etc/sysconfig/network-scripts/ifcfg-eth0 file should contain the following lines:
DEVICE=eth0
BOOTPROTO=dhcp
ONBOOT=yes

A configuration file is needed for each device to be configured to use DHCP.
Other options for the network script includes:
If you prefer using a graphical interface, refer to Chapter 5, Network Configuration for instructions on using the Network Administration Tool to configure a network interface to use DHCP.

Tip

For advanced configurations of client DHCP options such as protocol timing, lease requirements and requests, dynamic DNS support, aliases, as well as a wide variety of values to override, prepend, or append to client-side configurations, refer to the dhclient and dhclient.conf man pages.


[7] Kudzu is a hardware probing tool run at system boot time to determine what hardware has been added or removed from the system.