Esta página está en inglés, porqué puede ser útil en general. Cuando tenga un poquito de tiempo haré una versión en castellano (o a lo mejor puede hacerla alguien de Linux entre Comillas.

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This page explain how I managed to connect to the University wireless network, which is a IEEE802.1x network using PEAP and MSCHAPv2 protocols for authentication. I use a RTL8180-based cheap 802.11b PCMCIA card, on a Sony laptop with a recent Mandrakelinux distribution. So, if you have different setups, some command/location of file may change.

Moreover, this explain a quite manual procedure. It can be made more user-friendly for sure, integrating it in the general structure of your distribution. I have no time to hack this part.

Standard disclaimer: this one works for me. I will have no responsibility on the effects that this procedure could have on your hardware, software, time or environment...

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• The software you need.

  Basically, you need a wireless hardware and the corresponding software driver able to support dynamic WEP keys.

  To know if you have a wireless interface set up, issue the command: iwconfig and if you have an interface with wireless extension, it will appear like this:

  lo        no wireless extensions.
   
  eth0      no wireless extensions.
   
  eth1      no wireless extensions.
   
  wlan0     IEEE 802.11b  ESSID:"upco_wlan"
            Mode:Managed  Frequency:2.442GHz  Access Point: 00:11:5C:6B:90:E0
            Bit Rate:11Mb/s   Tx-Power:20 dBm   Sensitivity=0/3
            RTS thr:2432 B   Fragment thr:2432 B
            Power Management:off
            Link Quality:100/100  Signal level:-61 dBm  Noise level:-256 dBm
            Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
            Tx excessive retries:0  Invalid misc:0   Missed beacon:0
  

• For my card there is no native Linux driver, so that I use the ndiswrapper driver (thanks to Giridhar Pemmasani), which enable Linux to use Windows XP NDIS network drivers. I am using now release 1.1 which works perfectly out of the box.
• If you want to use the release 1.0 you need this additional patch that enables compatibility with the Cisco AP (Access Points) we have here. Notice that this patch is a bad hack; better use official ndiswrapper releases. Please notice, too, that with older release of this driver the connection is not going to work; unfortunately, almost all current Linux distribution ships a very old (0.8 or earlier) release.

  Do not ask me for installation instruction; there is a very nice wiki page which should have all the answers.

• Then you need a supplicant, for example wpa_supplicant (thanks to Jouni Malinen). I use release 0.3.8 with this configuration file as .config. (0.3.6 works too). Again, instructions on compiling and installing the wpa_supplicant come with the package.
• Next, to test the setup, I did a very strange hack: I disabled the network start from hotplug script, which went all the time into the way. I edited /etc/hotplug/net.agent and added near the top:

  mesg "Romano hack: do not hotplug network!"
  exit 1
  

  which is a bit rude but hey... when I'll find out how automate all, I'll report here.
• Next step: write a /etc/wpa_supplicant.conf that suits you. For example:

  eapol_version=1
  ap_scan=1
   
  network={
          ssid="upco_wlan"
          key_mgmt=IEEE8021X
          eap=PEAP
          identity="alumnos\romano"
          password="your-nice-pass-here"
          phase2="auth=MSCHAPV2"
  }

  In this file, the identity is composed by what here is called domain and username in Windows jargon, separated by a backslash.
• Ready to go! Now load the interface driver if necessary (in my case with modprobe ndiswrapper, "up" the interface with ifconfig wlan0 up, and run the supplicant:

  # ./wpa_supplicant -Dndiswrapper -iwlan0 -c/etc/wpa_supplicant.conf
  Trying to associate with 00:11:5c:6b:90:e0 (SSID='upco_wlan' freq=2442 MHz)
  Associated with 00:11:5c:6b:90:e0
  EAP-MSCHAPV2: Authentication succeeded
  EAP-TLV: TLV Result - Success - EAP-TLV/Phase2 Completed
  

  Note that the command is just the first line...
• If authentication is gone well, you just have to ask an IP to enter the network; in Mandrakelinux you use dhclient, others have pump:

  # dhclient wlan0
  Internet Systems Consortium DHCP Client V3.0.1rc14
  Copyright 2004 Internet Systems Consortium.
  All rights reserved.
  For info, please visit http://www.isc.org/products/DHCP
    
  Listening on LPF/wlan0/00:0b:9d:00:b2:6e
  Sending on   LPF/wlan0/00:0b:9d:00:b2:6e
  Sending on   Socket/fallback
  DHCPREQUEST on wlan0 to 255.255.255.255 port 67
  DHCPACK from 172.20.200.1
  bound to 172.20.200.6 -- renewal in 11227 seconds.
  

• It's all. Now you are on air. Congratulations!!!
• To automate it all, you can use this two scripts to start and, respectively, stop the connection:
  • To start:

    #! /bin/bash -x
    #
    modprobe ndiswrapper
    ifconfig wlan0 allmulti up
    wpa_supplicant -Dndiswrapper -iwlan0 -c /etc/wpa_supplicant.conf -Bw
    sleep 1
    dhclient wlan0
    

  • To stop:

    #! /bin/bash -x
    #
    killall wpa_supplicant
    killall dhclient
    ifconfig wlan0 down
    rmmod ndiswrapper
    

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