What does the term "implicit firewall policy" refer to in FortiGate?

The term "implicit firewall policy" in FortiGate refers to a policy that blocks all traffic by default. This means that unless there is a specific security policy defined to allow certain types of traffic, all other traffic is denied. By default, FortiGate operates on a principle of least privilege, ensuring that only explicitly permitted traffic flows through the firewall, thus enhancing security.

This approach is essential for maintaining a strong defense posture, as it minimizes the risk of unauthorized access and potential attacks. Administrators can then create specific policies to allow particular types of traffic, accommodating the needs of the network while still keeping unwanted traffic blocked.

In the context of FortiGate firewall management, understanding this implicit policy is crucial for correctly configuring and troubleshooting firewall rules.