The question is, why do you think the "rogue" device is connected? Does it show up in the IP list? Can you see traffic from the device? A MAC address can show up in the device list without being fully connected to the network.
MERGED QUESTION Question from bibin_kurian : "Hi i change my friends wifi password but some external guys still connected to the wifi.....?"
bibin_kurian :
Hi i change my friends wifi password but some external guys still connected to the wifi.....? How..?? And what can i do for that...?
kanewolf :
A reboot of the router after the WIFI and administrator password change will disconnect all devices. A MAC address may still show up in the list, but it isn't connected, it just attempted to connect.
also in the router put the mac address of our friend device on wi-fi permit list so others should not be able to connect .
MAC address filtering is not considered a valid security measure. Anyone with any knowledge can locate and spoof a valid MAC address in seconds, thus bypassing any filtering.
The question is, why do you think the "rogue" device is connected? Does it show up in the IP list? Can you see traffic from the device? A MAC address can show up in the device list without being fully connected to the network.