What type of control is a software firewall that prevents certain traffic from entering a device?

A software firewall that prevents certain traffic from entering a device is classified as a technical control. Technical controls are security measures implemented through technology and are designed to protect systems and networks. These controls include hardware and software solutions that function to restrict unauthorized access or modify the behavior of systems.

A software firewall specifically analyzes incoming and outgoing traffic against predetermined security rules, allowing or blocking data packets accordingly. This active process is a demonstration of a technical control because it involves the application of technology to enhance the security posture of a device.

While physical controls pertain to the tangible protection of hardware and infrastructure, and administrative controls relate to organizational policies and procedures, a software firewall operates at the technical level. Passive controls, on the other hand, typically do not intervene directly but rather log or monitor activity without actively preventing traffic or intrusions. Thus, in the context of how a software firewall functions, it clearly falls under the category of technical controls.