How to Enable & Disable the Ethernet Card in Linux

If you're using Linux, you can generally enable and disable an Ethernet card through the command line or through the graphical user interface. You may need to be an administrator on the computer to adjust the networking settings.

An Ethernet card is a device inside your computer for connecting to a local network – and often the internet – using a standard called Ethernet. It must be plugged into an Ethernet cable, similar to a phone line, and the cable is generally connected to a network router.

While wireless connections have gotten more prevalent, Ethernet connections can still be faster and more reliable and are still in use for some applications.

A network interface is the Linux term for the digital equivalent of a physical device like an Ethernet card or a Wi-Fi card. You can have Linux disable a network interface or enable it using the command line.

The most common command line tool for the job is a program called "ifconfig." If you simply run "ifconfig" with no arguments, it will give you a list of network interfaces, including whether they are on or off and what Internet Protocol addresses are associated with them.

Traditionally, wired Ethernet interfaces have names beginning with "eth" and wireless interfaces have names beginning with "wlan." A special "loopback" interface doesn't correspond to an actual card. It's set up for the computer to internally send messages without involving the network.

Run "ifconfig up" to have Linux activate a network interface and "ifconfig down" to have Linux disable the LAN connection on that interface. If you want to turn an interface off and back on, run the down command, then the up command.

Some Linux distributions include a newer tool called "ip." You can use this as well, typing "ip link set up" or "ip link set down" to toggle an interface on or off.

You may need to be a superuser to adjust the networking settings. If so, add "sudo" to the beginning of the command to run it as the root user. You'll be prompted to enter your password. If you don't have sudo access, contact someone who does.

Many modern Linux systems also let you adjust the networking settings via a graphical user interface.

On Ubuntu systems running the Gnome desktop environment, for example, you can use an applet called "network-manager" or "nm-applet" in the system tray. It's represented by an icon of two networked computers.

Right-click it to see options to enable and disable connections.