Joe, a client, wants to allow only specific portable devices to connect to his wireless network. Which of the following methods would BEST accomplish this?

Disabling SSID broadcast hides the network name from casual discovery but does not restrict which devices can connect - any device that knows the SSID can still join.

Every network adapter has a unique MAC (Media Access Control) address burned into its hardware. MAC filtering on a wireless access point or router lets the administrator define an explicit list of permitted MAC addresses, blocking all other devices from connecting. This directly fulfills the requirement to allow only specific portable devices onto the network.

Lowering radio power levels reduces the physical range of the wireless signal but does not authenticate or restrict specific devices within that range.

Directional antennas focus the signal in a specific direction to limit coverage area but cannot identify or block specific devices.