Entering only from route address

[eluser]Aken[/eluser]
Routes is a poor solution, because unless you direct it to a 404-specific controller, it'll still be a valid URL.

If you're that serious about it, I would add a quick check to the controllers themselves that check the URI, and if it matches the non-routed URL, throw a 404. You can create a MY_Controller with a method inside it to make that as easy as one line in each controller.