You can view the MAC address, IP address and client ID, and the DHCP lease time of client computers connected to your wireless network.
Open AirPort Utility, located in the Utilities folder in the Applications folder on a computer using Mac OS X, and in Start > All Programs > AirPort on a Windows computer.
Select the device you’re setting up, and then click Manual Setup. Enter the password if necessary.
Click Advanced in the toolbar, and then click Logging & Statistics.
Click “Logs and Statistics,” and then click DHCP Clients. You can see the Mac address, IP address, client ID, and lease time of clients on your network.
The client ID is optional and may not be required in your network.