iwconfig

Before we get started with aircrcak-ng, we need to make certain that BackTrack recognizes your wireless adapter. We can do this within any Linux system by typing:

• bt > iwconfig

We can see here that BackTrack recognizes my USB wireless card, and it tells me that it's capable of 802.11bgn, that the ESSID is off, that the mode is managed, etc.

iwconfig is used to display and change the parameters of the network interface which are specific to the wireless operation (e.g. interface name, frequency, SSID). It may also be used to display the wireless statistics (extracted from /proc/net/wireless).

In the free Berkeley Software Distribution UNIX operating systems, the role of iwconfig is performed by an expanded ifconfig command.

Sample iwconfig output

The following command displays information about the currently associated wireless network.

 $ iwconfig eth1
 
 eth1     IEEE 802.11g  ESSID:"OSU_PUB"  
          Mode:Managed  Frequency:2.427 GHz  Access Point: 00:0D:9D:C6:38:2D   
          Bit Rate=48 Mb/s   Tx-Power=20 dBm   Sensitivity=8/0  
          Retry limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=91/100  Signal level=-39 dBm  Noise level=-87 dBm
          Rx invalid nwid:0  Rx invalid crypt:860  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:39   Missed beacon:8