What inspection mode does FortiGate use if it is configured as a policy-based next-generation firewall (NGFW)?

Full Content inspection is a general term and not a specific FortiGate inspection mode, though it implies deep inspection capabilities which both proxy and flow modes can perform to varying degrees.

Proxy-based inspection is an alternative mode that FortiGate can use, where traffic is proxied through the FortiGate, allowing for more in-depth analysis and content modification, but policy-based NGFW defaults to flow-based for performance.

Certificate inspection is a specific security feature, often part of SSL/TLS inspection, which can be configured within both flow-based and proxy-based inspection modes, but it is not a standalone inspection mode itself.

FortiGate's policy-based NGFW mode primarily uses flow-based inspection, which analyzes traffic as it passes through the FortiGate without proxying, offering high performance and deep packet inspection for various security features like IPS and application control.