Chapter 14 Managing Devices for FortiOS 5.0 : Managing “bring your own device” : Device policies : Creating device policies : Setting Device Policy Options
  
Setting Device Policy Options
1. Optionally, enable Attempt to detect all Unknown device types before implicit deny.
2. Redirect all non-compliant/unregistered FortiClient compatible devices to a captive portal enables the captive portal. Select which device platforms to include.
3. Optionally, enable Prompt Email Address Collection Portal for all devices. This requests an email address from the device user. See “Guest access in a retail environment”.