Setting up a wireless adapter on Ubuntu server 12.04 LTS via CLI isn't THAT easy. Plug'n'Play doesn't simply work. Good thing there is Google. And a lot of helpful sites.
Insert the stick (or boot with it) and connect automaticly to the preferred network
This is not a tutorial. And it's realy not for the uninitiated. It's more like a short reminder for me, or people who have a basic idea what's happening here...
- Software: Vanilla Ubuntu 12.04 Server LTS
- Hardware: A USB-Wifi Stick (here a TP-Link TL-WN821N)
What was done:
This has to be done only once
Change to su mode
Execute following command, whereas you have to replace the two <> variables with your actual values. It will create a WPA2 Pre Shared Key based on your ESSID and passphrase
add at the top of the /etc/wpa_supplicant.conf file (above the "network") the line
then exit the su mode
Now we have to check if our settings work:
sudo wpa_supplicant –D wext –i wlan1 –c/etc/wpa_supplicant.conf
If everything works like expected, some message like "CTRL-EVENT-CONNECTED" will appear. Fine. Now lets move on:
Again, enter su mode and edit the file /etc/rc.local
add the following two lines just before the exit 0;
sudo wpa_supplicant –D wext –i wlan1 –c/etc/wpa_supplicant.conf -B sudo dhclient -4 wlan1
This should do the trick. Our Wifi will work. Obviously the rc.local could be a little bit more ... niftier. It could, for example check if there is a wifi stick present and if it is active for wlan1. But for a first shot, this will be enough.
One "problem" still exist: When you execute the wpa_supplicant part, I encounter some weird error messages:
ioctl[SIOCSIWENCODEEXT]: Invalid argument
The important part for me: I've got no problems with my wifi. just this message. When I've some time I will investigate a little bit.