Considerations about perimeter security

Steffo made some interesting comments to the meme, that firewalls or perimeter security isa thing of the past: Firewalls: No more perimeter security?. I agree to Steffo. As long there is no system, that is secure in it´s self (read: never), you need additional barriers outside the system. So the news about the dead of perimeter security are greatly exaggerated. To reuse the pattern of city walls: You don´t need a single wall, you need multiple ones. With doors not aligned in a row to each other.