Many Windows administrators are familiar with the ipconfig command line utility, which is used to get information about network interface configuration and make changes to it. Linux systems have a similar utility, ifconfig, which is a common part of the day-to-day tool belt of most Linux sysadmins. There are some distinct differences between ipconfig and ifconfig, however, such as the fact that the DOS/Windows ipconfig does not allow you to make changes to network configuration.
In general, you must be logged in as root or use sudo to make use of the ifconfig utility on a Linux machine. The ifconfig utility can be used either to simply get information about network interface configuration or to change configuration, depending on what options are used with the ifconfig command.