What is the difference between active and passive firewalls?

Active firewalls are designed to take an active role in managing network traffic by not only monitoring it but also modifying the traffic flows as necessary. This means they can enforce security policies in real-time, blocking or allowing traffic based on predefined rules. For instance, they can drop malicious packets or re-route traffic in response to certain criteria. This proactive approach is essential for environments that require stringent security controls and responsive measures against threats.

In contrast, passive firewalls primarily monitor network traffic without interacting with it. They typically log traffic data or alert network administrators about suspicious activity but do not take direct action to alter or block traffic. This fundamental distinction highlights the functional capabilities of active firewalls in providing dynamic security responses, while passive firewalls serve a more observational and less interventionist role.

This understanding is crucial for selecting the right firewall type based on specific network needs and threat models.