In Many Cases you will have to identify if the user or client is connected using his INTERNET via Wifi because many times it could be in idle state.
While capturing the handshake of WiFi many peoples face a problem and they are Unable to capture the handshake even if the clients are connected. This is because the client who is connected to his WiFi is not using his INTERNET so when you disconnect him from his internet their is no interchange of password in 4 way handshake because the internet and his machine is idle and is not in use , but if he is using the internet you will disconnect him and then he will reconnect himself to the internet and in this case you can capture a pure 4 way handshake which will be valid.
airodump-ng mon0 -a
Now this list all the internet AP in your range and below there will be active clients and their bssid,s the bssid will be the bssid of Router or modem and station will be the bssid of the network adapter .
As you can see i have few active clients below who are connected to their AP , in order to make it easy for you i suggest you to press TAB button while scanning and move it up and down to identify their active clients so now there is a section named " Frames " if the user is using his internet the frames will increase and if its in idle state the frames will not increase.
such as in my case bssid " 5c:0A:5B:F5:FE:0C " is using his INTERNET because frames are increasing.
So before you start capturing the handshake please identify if the user is using his internet or not if so then you will get success.
I hope you liked this little informative tutorial and for more check the below link
