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I'm trying to configure my wifi card in Ubuntu 10.10 server (no GUI, therefore no NetworkManager). I've found a bunch of similar questions here, but none that quite match my problem.

My card is recognised; running "iwconfig wlan0" gives something like this:

wlan0     IEEE 802.11g  ESSID:"networkname"  
  Mode:Managed  Frequency:2.437 GHz  Access Point: Not-Associated   
  Bit Rate:54 Mb/s   Tx-Power:20 dBm   Sensitivity=-121 dBm  
  RTS thr=2347 B   Fragment thr=2346 B   
  Power Management:off

And I can see my wifi network's SSID with "iwlist scan", so the card is definitely working on some level. I've tried following the Ubuntu docs, specifically running:

iwconfig wlan0 mode managed
iwconfig wlan0 channel 4
iwconfig wlan0 essid networkname

But this hasn't associated the network with an access point. I've also tried the command "iwconfig wlan0 key s:mypassphrase", but this is is rejected with "Invalid argument" -- do I need to enter the hex form of the key rather than the passphrase? Or am I missing something else entirely?

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up vote 0 down vote accepted

It turns out that iwconfig was a complete red herring. I instead tried configuring wpa_supplicant, and that did the job. For the benefit of future generations, here's the incantation that I used:

wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf

With the following wpa_supplicant.conf file:


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