Configure Linux DHCP client ( dhclient ) to persistently look for an IP address lease

Posted on in Categories , , , , last updated December 24, 2007

Q. I’ve HP Laptop installed with CentOS 5 workstation operating system. How can I configure Linux dhclient command to continuously requests an IP lease until one is granted by DHCP Server / Router?

A. You need to set the PERSISTENT_DHCLIENT option by editing Ethernet configuration file. This option is turned off by default.

Login as the root user

Open /etc/sysconfig/network-scripts/ifcfg-eth0 file to set eth0 to persistently look for an IP address lease:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0
Append line PERSISTENT_DHCLIENT=1, at the end configuration should look as follows:
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
PERSISTENT_DHCLIENT=1

Save and close the file. Restart networking service or reboot laptop / desktop to test the changes:
# /etc/init.d/networking restart

Please note that your network switches and other protocol may need to configure properly to work with this option.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

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  1. “Save and close the file. Restart networking service or reboot laptop / desktop to test the changes:
    # /etc/init.d/networking restart”

    should be:
    # /etc/init.d/network restart

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