25.3. 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[1] should recognize it and prompt for the configuration of the corresponding kernel module for it. Be sure to check the Hardware Compatibility List available at http://hardware.redhat.com/hcl/. If the network card is not configured by the installation program or Kudzu and you know which kernel module to load for it, refer to Chapter 40 Kernel Modules for details on loading kernel modules.

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:


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:


A configuration file is needed for each device to be configured to use DHCP.

Other options for the network script include:

For a graphical interface for configuring a DHCP client, refer to Chapter 19 Network Configuration for details on using Network Administration Tool to configure a network interface to use DHCP.



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