When you like to make a simple Whitelist for a Fortigate with FortiOS V4.0 MR3 you can do the following. You can create under the menu UTM => Web Filter => URL Filter a new list. I called this list „White List“. You can add new URL for this List. To allow this URL you have to set the Action Exempt. Add all the URL’s you like to access if they are blocked by a category.
Now you can add the „White List“ to a Web Filter Profile.
Under Pofle choose your Web Filter Profile and add the Filter to the list. In the Profile Overview the URL List is under the blocking Category. It doesn’t matter because the firewall checks first the URL List before it checks the Category List. Consequently the URL’s in the URL List are always allowed.