Connecting Ubuntu to wireless networks from the command line

I usually use Linux with IceWM window manager without Gnome nor KDE desktop environments, where I have to manually connect to wireless networks using console commands. Here, I show how I do it. This tip should be also useful if you are working under non-graphical session and needing a wireless network connection, such as in case of headless servers or embedded systems.

Method

First, check our wireless interface name and access points:

$ sudo iwlist scan
ra0       Scan completed :
          Cell 01 - Address: 00:23:F8:AD:40:0E
                    ESSID:"Northeast"
                    Mode:Managed
                    Channel:6
                    Quality:100/100  Signal level:-29 dBm  Noise level:-81 dBm
                    Encryption key:on
                    Bit Rates:18 Mb/s

In this case, we see that our wireless interface is ra0, and the access point is "Northeast" with encryption (WEP access point).

Bring up the wireless interface:

$ sudo ifconfig ra0 up

Bind the access point to the wireless interface with key being initialized. (If your access point is not encrypted, omit "key open".)

$ sudo iwconfig ra0 essid "Northeast" key open

Set our WEP key "77022" (you should know it somehow!). (If your access point is not encrypted, skip this step.)

$ sudo iwconfig ra0 essid "Northeast" key s:77022

Get an IP address from the access point:

$ sudo dhclient ra0

Now, we joined the wireless network!