What type of Firewall mode operates independently, without supporting interfaces in FortiGate?

The correct choice identifies the proxy-based mode, which operates independently and does not rely on supporting interfaces in FortiGate. In proxy-based mode, the FortiGate device acts as an intermediary between the user and the destination server. It establishes a separate session for each connection, allowing it to inspect the traffic in detail before forwarding it. This allows for more granular control as it can analyze application-layer protocols and apply security measures effectively.

In contrast, flow-based mode operates by inspecting traffic as it flows through, maintaining a stateful inspection model. This mode relies on the interfaces to manage traffic between the source and destination without creating separate sessions for inspection, which may limit its ability to inspect certain protocols as thoroughly as proxy-based mode.

Profile-based mode is a concept related to the implementation of security policies and profiles but does not define how traffic is processed in terms of independent operation. Advanced mode is not a standard term used in the context of firewall operation in FortiGate and does not represent an actual mode of operation.

By distinguishing proxy-based mode as the only option that operates independently, it clarifies its unique role in traffic management and security within FortiGate devices.