A Demilitarized Zone (DMZ), also known as a screened subnet or perimeter network, is a separate network segment that resides between an organization's internal network and the external, untrusted networks. It is designed to host publicly accessible resources, such as web servers, email gateways, or FTP servers while providing an additional layer of security for the internal network. DMZs are often implemented using multiple firewalls or screening routers, with one firewall separating the DMZ from the external network and another firewall separating the DMZ from the internal network. This configuration allows for granular control over traffic flow and access permissions, ensuring that even if a resource in the DMZ is compromised, the internal network remains protected. While a DMZ is not a perimeter firewall itself, it is an integral part of an organization's perimeter security strategy. It works in tandem with perimeter firewalls and other security measures to enhance the overall defense against cyber threats.