IP Configuration in Ubuntu

Here is a howto about the configuring ip using networking related files in Ubuntu / Debian systems.

File: /etc/network/interfaces
    This file contains network interface configuration information  for the ifup and ifdown commands. This is where you configure how your system is connected to the network.

Three important Interfaces are:

        # lo: Loopback interface (it is an internal 

            networking mechanism. It is used to

            test applications...)
        # eth0: First ethernet interface card
        # wlan0: First wireless network interface

Use following command to edit the interfaces file

$ sudo gedit /etc/network/interfaces

Add one or more of the stanzas below 

    Static IP example:
    auto lo
    iface lo inet loopback

    auto eth0
    iface eth0 inet static
            address 208.88.34.106
            netmask 255.255.255.248
            broadcast 208.88.34.111
            network 208.88.34.104
            gateway 208.88.34.110
                   

    Dynamic IP (DHCP) example:
    auto lo
    iface lo inet loopback

    auto eth0
    iface eth0 inet dhcp

    auto eth1
    iface eth1 inet dhcp

    auto eth2
    iface eth2 inet dhcp

    auto ath0
    iface ath0 inet dhcp

    auto wlan0
    iface wlan0 inet dhcp
                   
    Lines  beginning with the word "auto" in the interfaces file are used to identify the physical interfaces to be brought up when ifup is run with the -a option.  (This option  is  used by the system boot scripts.)  Physical interface names should follow the word "auto" on the same line.

GUI Network Tools:

    * NetworkManager or wicd can be used as the GUI tools for the network management. Better use wicd network manager if you have to rely more upon the wireless internet than the wired ones.