If you use captive portal for your wireless solution you may notice certain mobile devices such as the iPad running iOS6 will require you to log into the captive portal after each time you use the device. This is because the wireless radio on the iPad is turned off when it sleeps and the captive portal timers reset thus requiring a log in each time. This typically isn’t an issue for mobile device that keep wifi enabled even during sleep. If preventing wifi from turning off on your mobile device isn’t an option then the following settings could be changed on the Fortigate wireless controller:

Change the user timeout setting:

config user setting
set auth-timeout 480
end

The wireless client timeout may also need to be changed:

config wireless-controller timers
set client-idle-timeout 0
end