How to Change an Internal IP in Kubuntu

If your router moves IP addresses around, due to dynamic IPs, it can make a mess of your port-forwarding setup. If you need to keep the IPs dynamic, you can manually change the IP to match what you need.

Difficulty: Easy

Instructions

Things You'll Need:

• Computer with Kubuntu or variant

1. Before changing the IP address assigned by your router, you will want to make sure it is available. You can check availability by pinging the IP you want by opening your favorite Command Line Interface (CLI) application (Konsole, Terminal or Yakuake) and typing: ping -c 4 192.168.1.2 . The IP address varies by what your router has setup for assignment. This is just an example. The command will send 4 packages to the IP address you specify and hope to get a response. We, on the other hand, do not want a response. If you do not have a response, skip to step 3. If you receive a response, proceed to step 2.

2. If the IP address is taken by another computer, you can choose to turn off the computer or disable the network connection. Either method will work to release the IP address. The command in Kubuntu and its variants is: sudo ifconfig eth0 down. This will turn off the network card. If it is connected to a printer or other network device, simply turn it off.

3. With the IP address available, and your CLI application open, we can assign it to the computer by typing: sudo ifconfig eth0 192.168.1.2 . The IP address will vary, but you will know this information since you are the Network Administrator. This will setup the IP address for the computer. Repeat as many times necessary for other computers.

Tips & Warnings

• eth0 is eth zero. This means ethernet device zero. In all computer languages, zero counts as a number.
• If you want to see the device and IP address assigned, you can type "ifconfig" in Konsole, Terminal and Yakuake.
• This tutorial is for changing your network IP address. Contact your Internet Service Provider to change your world-viewed (broadcasted) IP address.
• When changing IP addresses, make sure it is not being used elsewhere. This will complicate network communications.

[pianistic]

on 11/13/2008 Thanks for sharing your knowledge.

[Wasatch]

on 11/13/2008 Good article. You know your stuff. Thanks