What is the purpose of a demilitarized zone on a network?

A demilitarized zone (DMZ) is a buffer zone between a trusted internal network and an untrusted external network (usually the internet). Public-facing services like web servers, email servers, and DNS servers are typically placed in the DMZ. These nodes can be accessed from the internet, but the DMZ design ensures that unauthorized access to the internal network is blocked or highly restricted.

The purpose is to provide access to certain systems without exposing the internal network directly.