When designing a defense-in-depth strategy, which layer should be addressed first as the primary boundary between internal and external networks?
The perimeter network sits between trusted internal networks and untrusted external ones, so it forms the primary boundary where traffic is filtered and inspected first. Addressing it initially establishes the outermost control before hardening internal segments.
Why this answer
The perimeter network (DMZ) is the first line of defense that separates the internal network from untrusted public networks.