To start smelling the frequencies we need a wifi card compatible with monitor mode, this means it theoretically the monitor interface is passive – just receive packets! But with some drivers like mac80211 we can also transmit packets – Packet Injection! Wonderland
More information about packet Inspection here!
We have two methods to put our interface into monitor mode, first we can use airmon-ng tool or the iwconfig command.
Airmon-ng tool is a full app to deal with interfaces monitor mode, we can put an interface monitor mode and we can specify a specific channel to start monitoring avoiding channel hopping.
Starting interface Wlan0 into monitor mode in channel 6
#sudo airmon-ng start wlan0 6
usage: airmon-ng <start|stop> <interface> [channel] or airmon-ng <check|check kill>
#airomon-ng stop wlan0
#airmon-ng start wlan0
Airmon-ng – Start Monitor
If you need help choosing on card verify our list here!
#iwconfig wlan0 mode monitor
What are the best Wifi cards to crack wifi passwords?
Some errors you may find!
Found 4 processes that could cause trouble. If airodump-ng, aireplay-ng or airtun-ng stops working after a short period of time, you may want to kill (some of) them!
To resolve this problem these days the airmon-ng tools already have a parameter to kill the processes that could cause troubles, like:
#sudo airmon-ng check
#sudo airmon-ng check kill
If you want, you can use the Unix command kill to terminate the processes that are interfering with wifi interface, something like:
# kill 635 -> Has we can see at the picture above the process with the pid 635 it’s from Network Manager from my machine.
And that’s it, you can start smell the frequencies around the world! Some of theme smell pretty nice
And if you have been having problems with your wifi cards drivers, check this topic here!