Chapter 6 Deploying Wireless Networks : Configuring a WiFi LAN : Defining a wireless network interface (SSID) : Configuring security
  
Configuring security
Using the web-based manager, you can configure Captive Portal security or Wi-Fi Protected Access version 2 (WPA2) security modes WPA2-Personal and WPA2-Enterprise. Using the CLI, you can also choose WPA/WPA2 modes that support both WPA version 1 and WPA version 2.
WPA2 security with a pre-shared key for authentication is called WPA2-Personal. This can work well for one person or a small group of trusted people. But, as the number of users increases, it is difficult to distribute new keys securely and there is increased risk that the key could fall into the wrong hands.
A more secure form of WPA2 security is WPA2-Enterprise. Users each have their own authentication credentials, verified through an authentication server, usually RADIUS. FortiOS can also authenticate WPA2-Enterprise users through its built-in user group functionality. FortiGate user groups can include RADIUS servers and can select users by RADIUS user group. This makes possible Role-Based Access Control (RBAC).
By default, WPA2 security encrypts communication using Advanced Encryption Standard (AES). But some older wireless clients support only Temporal Key Integrity Protocol (TKIP) . You can change the encryption to TKIP or negotiable TKIP-AES in the CLI. For example, to accomodate clients with either TKIP or AES, enter:
config wireless-controller vap
edit example_wlan
set security wpa-personal
set passphrase "hardtoguess"
set encrypt TKIP-AES
end
Captive Portal security connects users to an open web portal defined in replacement messages. To navigate to any location beyond the web portal, the user must pass FortiGate user authentication.