Turning your Broadcom BCM4312 wireless card into monitor mode on Ubuntu 11.10

By default, when installed on Ubuntu 11.10, BCM4312 uses wl driver which don't support monitor mode



Also, the card is tagged as eth2 interface

Monitor mode is required in order to use Aircrack-ng suite. To enable monitor mode fellow these steps

1/ Install the b43-lpphy driver
      sudo apt-get install firmware-b43-lpphy-installer

2/ Unload the wl driver
      sudo modprobe -r wl
        
3/ Load the b43 driver
      sudo modprobe b43

    The name of the card interface will then change to wlan0

4/ Now, you can put the card into monitor mode by disabling and then enabling wlan0

 

   As you can see, a wireless logical interface, mon0, was created. You will refer to this interface when using
   monitor mode capabilities (Aircrack-ng, Wireshark…)

5/ To load b43 driver automatically at boot, add  b43 to /etc/modules file

6/ To disable loading wl driver automatically at boot, blacklist it
    add blacklist wl to  /etc/modprobe.d/blacklist.conf file

When using aireplay-ng, you will receive an error message about negative channel. the card will listen on channel -1 !!


To resolve this issue, fellow this procedure