The ________ is a subnet that contains all of the servers and application proxy firewalls that must be accessible to the outside world.

• A. Internet Subnet
• B. Server Subnet
• C. External Subnet
• D. None of the Above

Answer: (D)

Public-facing servers and application proxies are placed in a DMZ (demilitarized zone), a separate subnet designed at the network edge to host services that must be accessible from the Internet while protecting the internal network. This zone acts as a buffer: external traffic goes to the DMZ, where it can interact with the exposed services, but the internal network remains isolated behind firewalls and strict access controls. If a server in the DMZ is compromised, the breach has limited reach into the internal network due to the added security boundary.

The options given aren’t standard terms for this concept. An “Internet Subnet” or “External Subnet” isn’t a recognized naming convention for the zone that hosts public-facing servers. “Server Subnet” is too generic and could refer to any set of servers, not specifically those exposed to the outside world. Therefore, none of the above describes the correct, widely used concept, and the intended answer is that none of the above. The correct term you’re looking for is DMZ (perimeter network).