1. First of all you need to get the MAC address of all the device that is being currently connected to your wifi network. For that you need to Download WifiGuard For Windows.
  2. Now download and install this tool in your windows PC and launch it and select the network 192.168.1.1 from the list.

  3. Now start scanning devices and you will see list of all the devices currently connected to your wifi, note down the MAC address of the devices that belongs to you only and anyone of person whom you share your wifi.
  4. Now time to apply MAC filter on your router, this will only allow selected devices to connect to your wifi network, for complete guide visit our post Allow Selected Devices To Connect To Your Wifi.
  5. Now MAC filter will get enabled and only the devices listed in the router settings will now have access to your wifi network and no other will be able to get connected to your wifi.Thats is you are done will kicking off all unknown devices from your wifi network.