Chapter 6 Deploying Wireless Networks : Configuring a WiFi LAN : Defining a wireless network interface (SSID) : Configuring security : Captive Portal security
  
Captive Portal security
Captive Portal security provides an access point that initially appears open. The wireless client can connect to the AP with no security credentials. The AP responds to the client’s first HTTP request with a web page requesting user name and password. Until the user enters valid credentials, no communication beyond the AP is permitted.
For more information about captive portals, see “Captive portals”.