Release & Renew A DHCP Address In Ubuntu 14.04

Most of the time, when you connect your Ubuntu computer to a network it will have a dynamic address, commonly called a DHCP address (an acronym for Dynamic Host Configuration Protocol). You plug your computer into the network, or connect wirelessly, and the network’s DHCP server assigns your computer a dynamic IP address. Typically, a DHCP address has a lease, a time period your computer is allowed to keep the address. If your computer is still connected to the network when the lease is up, the DHCP server will automatically renew the lease. If it is not, the server will assign the address to another computer on the network. Because of this, sometimes you have to manually release and renew a DHCP address. In Ubuntu, you can do so through the Terminal utility, Ubuntu’s command-line application.

To release an assigned DHCP address from the Terminal, first launch the Terminal by going to the Dash, searching for “Terminal”, and then clicking on the icon for Terminal when it appear. You can also launch the Terminal by hitting the CTRL+ALT+T keys simultaneously.

Once the Terminal launches, type this command and then hit the ENTER key:

sudo dhclient –r

Enter your password to authenticate (you must perform this task as a user with Administrative rights), and Ubuntu will release its DHCP address. To obtain a new one, use the dhclient command again, but this time without any arguments:

sudo dhclient

Ubuntu will contact the network’s DHCP server and obtain a new address.

-JM