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I am trying to connect to my WEP network just using the command-line (Linux).

I run:

sudo iwconfig wlan0 mode Managed essid 'my_network' key 'xx:xx:... hex key, 26 digits'

Then I try to obtain an IP with

sudo dhclient -v wlan0


sudo dhclient wlan0

without success (tried to ping google.com).

I know that the keyword is right, and I also tried with the ASCII key using 's:key', and again, the same result.

I get the message below when running dhclient:

Listening on LPF/wlan0/44:...
Sending on   LPF/wlan0/44:...
Sending on   Socket/fallback
DHCPDISCOVER on wlan0 to port 67 interval 3 

I have no problem connecting with WICD or the standard Ubuntu tool.

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Side note - don't use WEP, use WPA2 –  icyrock.com Sep 29 '13 at 2:12
Can you please post the results of iwconfig without any parameters too. What version of Linux are you using? –  Danijel J Sep 29 '13 at 4:20
The OP might use WEP for his own reason. It is considered shallow in perspective of security, but some people just still prefer it. –  Danijel J Sep 29 '13 at 4:41

1 Answer 1

Option 1

Just edit /etc/network/interfaces and write:

auto wlan0
iface wlan0 inet dhcp 
                wpa-ssid {ssid}
                wpa-psk  {password}

After that write and close file and use command:

sudo dhclient wlan0

Replace {ssid} and {password} with your respective WiFi SSID and password.

Option 2

This is going to be more of a 1. Assuming your Wireless network card is wlan0 2. Assuming your Wireless network is "Wifi2Home" 2. Assuming your Wireless network key is ASCII code ABCDE12345

First, get your WiFi card up and running:

sudo ifconfig wlan0 up

Now scan for a list of WiFi networks in range. You might be typing your name wr$

sudo iwlist wlan0 scan

This will show you a list of wireless networks, pick yours from the list:

sudo iwconfig wlan0 essid Wifi2Home key s:ABCDE12345

To obtain the IP address, now request it with the Dynamic Host Client:

sudo dhclient wlan0

You should then be connected to the WiFi network. The first option is better, because it will be able to run as a cron job to start up the wifi whenever you need it going. If you need to turn off your WiFi for whatever reason, just type:

sudo ifconfig wlan0 down


I have also seen people using alternative commands. I use Debian, Solaris and OSX, so I'm not 100% sure if they are the same on Ubuntu. But here they are:

sudo ifup wlan0 is the same as sudo ifconfig wlan0 up
sudo ifdown wlan0 is the same as sudo ifconfig wlan down

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