Configure wireless from commandline

[sundar22in]

How can we configure a wireless network from commandline in Ubuntu?

I understand iwlist will give us the list of access points.

Next using iwconfig it is possible to connect to a wireless network without network manager. Could you please help with details of the step to connect to a wireless network using commandline?

[chili555]

First, it is difficult to do with Network Manager working or even installed. If you have NM removed, please read on!

Confirm your wireless card has a driver associated with it. Is there a wireless interface in iwconfig? If so, find the exact name of your access point with:
sudo iwlist wlan0 scanSubstitute your wireless interface, if it's not wlan0. You will get a result similar to this:
wlan0 Scan completed :
Cell 01 - Address: 99:24:56:2Z:D7:89
Channel:1
Frequency:2.412 GHz (Channel 1)
Quality=65/70 Signal level=-45 dBm
Encryption key:on
ESSID:"mylilrouter"

Ask your wireless interface to associate with the access point:
sudo iwconfig wlan0 essid mylilrouterIf there is any encryption, supply those details. Here is an example for WEP:
sudo iwconfig wlan0 key 0123456abcdNow ask for an IP address:
sudo dhclient wlan0WPA encryption is a bit more complex.

You can set your details in /etc/network/intefaces:
auto lo
iface lo inet loopback

auto wlan0
iface wlan0 inet dhcp
wireless-essid mylilrouter
wireless-key 0123456abcd

#auto eth0
iface eth0 inet dhcp

[sundar22in]

Hello,

Thank you very much for the response.

I tried the above steps.. but the DHCP client did not run successful.

I use WPA Personal encryption, so I tried editing the /etc/network/interfaces file mentioned above. Should we give the key in hexadecimal value? I gave as normal text:

wireless-key MY_KEY_AS_TEXT


Is this correct?

[chili555]

I use WPA Personal encryption,Remember I said WPA is a bit more complex? Please see: http://ubuntuforums.org/showthread.php?t=318539

[roydrager]

Many thanks to Chili555 for this fix to connect wireless from the command line. Uninstalling the network-manager package did the trick. With network-manager installed and the NetworkManager process running in the background, all my configuration commands had no effect or resulted in crazy output.

My /etc/network/interfaces file:


auto lo
iface lo inet loopback

iface wlan0 inet dhcp
wireless-essid linksys
wireless-key xxxx-xxxx-xxxx
wireless-mode Managed
auto wlan0


On this router it turns out I have to write the WEP key with dashes after every four characters. Was warned about that trick in this helpful wifi doc:
https://help.ubuntu.com/community/WifiDocs/WirelessTroubleShootingGuide

and iwconfig showed the key formated that way when network manager was running the wifi.)

My command line commands:



sudo apt-get remove network-manager
sudo invoke-rc.d networking restart
iwlist wlan0 scan
sudo iwconfig wlan0 essid "linksys" mode Managed key xxxx-xxxx-xxxx
sudo dhclient wlan0


I don't know if the mode Managed was necessary but many tutorials included a mode option and iwconfig had mode Managed when NetworkManager was running it.

Anyway much simpler than many confusing older "ifupdown" methods from old documentation! Thanks again to Chili.