Without WLAN MAC access restriction, any WLAN client can join (authenticate with) 
a Wi-Fi network if they know the network name (also called the SSID) and perhaps a 
few other security parameters like encryption keys.  
 
When WLAN MAC access is enabled, however, the access point or router performs 
an additional check on a different parameter. Obviously the more checks that are 
made, the greater the likelihood of preventing network break-ins. 
 
To set up WLAN MAC access rules, you as a WLAN administrator must configure a 
list of clients that will be allowed to join the network.