Router-modem WiFi Whitelist MAC Address

[yulnim]

I setup my ISP's router-modem to have a whiltelist of MAC address. I'm aware that MAC address can be spoofed to bypass my whitelist but problem is I keep seeing random Android devices with MAC addresses not on the list connected wireless based on the router's GUI.

Is that really possible? Or can it mean the firmware of my router-modem is faulty?

I have also changed the following:
- Router's default user/pass
- SSID and passphrase
- Set authentication type to WPA2-PSK
- Set encryption to AES

I've only had this router-modem for about 2 days yet already saw 12 Android devices with their own unique MAC address connected to my WiFi. So far I've been only able to ping one of them, via cmd, which I assume means they were really able to connect to my WiFi.

At the moment I just disabled the WiFi. Kinda stumped on how else to secure our WiFi and if there are really people in our area that are so dedicated to hack into our Wifi.

 

[jsmithepa]

Does your SSID shows a padlock next to it? Does it have a guests mode?

 

[yulnim]

Does your SSID shows a padlock next to it? Does it have a guests mode?

Do you mean when checking/connecting to SSID from a mobile device or laptop? Then yes it has a padlock on it. But from router GUI no, and no for guest mode either.

But I think I figured out what's causing it. As I said I only got this router-modem 2 days ago. And based on my understanding this model actually has multiple broadcasted SSIDs enabled by default.

I only properly setup the first SSID I saw. The other 3 SSIDs were left without passphrase even. Damn my ISP's technicians for not even telling me that. My own failure as well for not noticing the setting for the other SSIDs (they were "hidden" by drop down list).

Anyway so far so good! Haven't seen any unknown devices connected to our Wi-Fi.