What is a demilitarized zone (DMZ) in network security?

A demilitarized zone (DMZ) in network security refers to a network segment that serves as a buffer between trusted internal networks and untrusted external networks, such as the internet. This concept is vital for enhancing security by isolating an organization's internal network from potentially hostile external traffic.

In practice, a DMZ typically hosts servers that need to be accessible from the external network, like web servers, email servers, or DNS servers, while keeping the internal network secure. The arrangement allows for controlled access and monitoring of incoming and outgoing traffic. By placing publicly accessible services in the DMZ, organizations can limit exposure to their internal network, thereby reducing the risk of external attacks compromising sensitive data or critical systems.

This architectural design is essential for maintaining a layered security approach, providing an extra layer of defense. If an attacker successfully breaches a server in the DMZ, they still face additional obstacles before they can access the internal network.