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7 Useful Linux Networking Commands

ifconfig, iwconfig, ethtool

  • April 19, 2010
  • By Eric Geier

Though you can usually manage your network settings via the GUI in most Linux distros these days, it's always good to be familiar with the command-line tools. So we're going to review some select commands from a couple of tools that are typically included in the popular Linux distros. Remember, if you want full details on the tool and its options, refer to its man page: type man followed by the tool name. Now bring up a terminal and let's get started!

ifconfig for basic interface and IP configuration

The ifconfig tool (derived from interface configurator) provides a few very basic, but important, functions. It lets you turn network adapters on and off and assign IP address and netmask details. Here are some of the common commands:

View current configuration of network interfaces, including the interface names:

ifconfig

Turn an adapter on (up) or off (down):

ifconfig

Assign an IP address to an adapter:

ifconfig

Assign a second IP address to an adapter:

ifconfig

Example: ifconfig eth0:0 192.168.1.101

ethtool managages ethernet card settings

Ethtool lets you view and change many different settings for ethernet adapters (which does not include Wi-Fi cards). You can manage many different advanced settings, including tx/rx, checksumming, and wake-on-LAN settings. However, here are more basic commands you might be interested in:

Display the driver information for a specific network adapter, great when checking for software compatibility:�

ethtool -i

Initiate an adapter-specific action, usually blinking the LED lights on the adapter, to help you identify between multiple adapters or interface names:

ethtool -p

Display network statistics:

ethtool -S

Set the connection speed of the adapter in Mbps:

ethtool speed <10|100|1000>�

iwconfig for wireless configuration

The iwconfig tool is like ifconfig and ethtool for wireless cards. You can view and set the basic Wi-Fi network details, such as the SSID, channel, and encryption. There's also many advanced settings you can view and change, including receive sensitivity, RTS/CTS, fragmentation, and retries. Here are some commands you may want to try:

Display the wireless settings of your interfaces, including the interface names you'll need for other commands:

iwconfig

Set the ESSID (Extended Service Set Identifier) or network name:

iwconfig essid

Example: iwconfig "my network"

Example: iwconfig any

Set the wireless channel of the radio (1-11):

iwconfig

Input a WEP encryption key (WPA/WPA2 isn't supported yet; for this you need wpa_supplicant):

iwconfig eth0 key

Only allow the adapter to connect to an AP with the MAC address you specify:

iwconfig ap

Example: iwconfig eth0 ap 00:60:1D:01:23:45

Set the transmit power of the radio, if supported by the wireless card, in dBm format by default or mW when specified:

iwconfig txpower

Example: iwconfig eth0 txpower 15

Example: iwconfig eth0 txpower 30mW

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