Traditionally, the foundation of enterprise network security has been a perimeter firewall behind an organization’s Internet gateway or a pair of firewalls encompassing a demilitarized zone (DMZ) which offer an isolated environment between a completely trusted enterprise network and untrusted external network. However, merely characterizing the entire enterprise network as ‘trusted’ and considering it as ‘flat’ (i.e. as a single segment) creates an environment that requires an antagonist to o...