What should web servers be placed in after hardening the operating system?

Placing web servers in a DMZ (Demilitarized Zone) after hardening the operating system is a best practice for enhancing security. The DMZ acts as a buffer zone between an organization's internal network and the external internet, allowing for controlled access to public-facing services such as web servers while isolating them from the internal network.

This setup is important because it minimizes exposure to potential threats from the internet, as any attack on the web server would not directly compromise the internal network. The hardened operating system on the web server provides an additional layer of security, but placing it in a DMZ further enhances its protection by controlling the incoming and outgoing traffic. Any unauthorized access attempts can be contained within the DMZ, providing an extra layer of security against various threats.

Other environments, such as a LAN (Local Area Network), would not provide the necessary isolation from external threats, while a VPN (Virtual Private Network) is primarily used for secure remote access rather than for structuring web services. Similarly, a VLAN (Virtual Local Area Network) can improve traffic management within a local network but does not offer the same level of perimeter security that a DMZ provides for exposed web services.