Connect your mobile device to your router's WiFi then open the Linksys app.
Log in to your Linksys cloud account. If you are using an iOS device, click here. If you are using an Android™ device, click here.
On the Dashboard, tap the menu icon on the upper-left corner.
Tap Advanced Settings and select WiFi MAC Filters.
Tap Edit at the top-right corner of the screen to change the WiFi MAC Filters settings.
Select which WiFi MAC Filter to use.
Deny Access – All MAC addresses except those in the list are allowed to join the network. Enter the MAC address of the device you want to deny access, then tap Add a Rule. Alternatively, you may tap on the Select from device list option. Make sure to tap Save at the top-right corner of the screen.
NOTE: If you choose to disable this feature, tap Off and Save to apply the changes.