use dhcp on eth0 using command line

Question

I am trying to set the eth0 interface to use dhcp to get an ipv4 address, using the command line. I can manually change the ip address using

sudo ifconfig eth0 x.x.x.x netmask x.x.x.x

Is there a similar command to use to set eth0 to get an address using dhcp? I tried typing:

sudo dhclient eth0 

however the ip address doesn't change when I type this. The /etc/network/interfaces file was set to

iface eth0 inet manual 

which I then changed to:

auto eth0
iface eth0 inet dhcp 

however this doesn't change the eth0 ip address even if the system is rebooted.

Answer 1

If your dhcp is properly configured to give you an IP address, the command:

dhclient eth0 -v 

should work. The option -v enable verbose log messages, it can be useful.

If your eth0 is already up, before asking for a new IP address, try to deconfigure eth0.

To configure the network interfaces based on interface definitions in the file /etc/network/interfaces you can use ifup and ifdown commands.

Answer 2

First you need to run the following command:

dhclient -v -r

Then change the ip adress:

ifconfig eth0 xx.xx.xx.xx

Change xx.xx.xx.xx with the needed ip_adress