Which of the following is NOT a valid security log subtype for FortiGate?

The correct answer indicates that "System Event" is not a valid security log subtype for FortiGate. In the context of FortiGate logging, security log subtypes are specifically related to actions and events that pertain to network security monitoring and threat management.

In the case of Web Filter, DNS Query, and Antivirus, each of these subtypes holds significance in terms of capturing specific security-related information. For instance, the Web Filter log subtype records data regarding web traffic and threats that may originate from web activity. Similarly, the DNS Query subtype captures logs related to DNS requests, which can help in identifying malicious activities like domain lookups. The Antivirus subtype logs events related to detected viruses and malware, helping administrators track potential threats on their networks.

On the other hand, the System Event log subtype generally relates to non-security-specific system activities within the FortiGate device itself, such as configuration changes, system diagnostics, and routine operations that do not directly pertain to the security posture of the network. This distinction is critical because effective security management focuses on monitoring specific threats and attacks rather than broader system operations.

Thus, by identifying that "System Event" is not categorized under the security log subtypes recognized by FortiGate, the response highlights the importance