In FortiOS 7.6, web filter profiles are inspection-mode dependent. Certain advanced web filtering features-such as daily category usage quota-are only supported when the firewall policy is operating in proxy-based inspection mode.
Why the profile is not visible
The profile restrictmedia-profile includes a daily category usage quota.
Daily quotas are a proxy-based web filtering feature.
If the firewall policy is configured with:
Inspection mode: Flow-based
Then FortiGate will not display proxy-only web filter profiles in the Web Filter drop-down list.
FortiGate automatically filters the available profiles based on feature compatibility with the policy's inspection mode.
This behavior is explicitly documented in the FortiOS 7.6 Web Filtering and Inspection Mode Compatibility sections.
Why the other options are incorrect
A . Already referenced in another firewall policyWeb filter profiles can be reused across multiple policies. This does not hide them.
B . Firewall policy is in no-inspection mode instead of deep-inspectionSSL inspection depth affects HTTPS visibility, not whether a web filter profile appears in the drop-down list.
C . Naming convention restrictionFortiOS does not restrict profile selection based on naming conventions.

"When using FortiGuard servers for DNS, FortiOS uses DNS over TLS (DoT) by default to secure the DNS traffic. New FortiGuard DNS servers have been added as primary and secondary servers." Technical Deep Dive:
The correct answer is C. It uses DNS over TLS.
This is a direct default-behavior question. If you configure FortiGuard servers as DNS servers and do not change anything else, FortiGate uses DoT rather than plain DNS. That means the DNS session is encrypted, which protects DNS queries from simple interception or tampering on the path.
Why the other options are wrong:
A is standard clear-text DNS behavior, not the FortiGuard DNS default stated in the guide.
B is incorrect because the guide specifically says DNS over TLS, not DNS over HTTPS.
D is incorrect; the guide does not describe UDP 8888 as the default transport for this DNS use case.
Operationally, this matters because FortiGate relies on DNS not only for client-facing services, but also for resolving objects and securely reaching cloud-based services. Using DoT improves confidentiality for those DNS lookups.

According to the FortiOS 7.6 Study Guide and technical documentation, conserve mode is a protective state triggered when memory utilization reaches the Extreme Threshold (typically 95% by default). When this occurs, the FortiGate implements several measures to prioritize system stability over new functionality. One of the primary restrictions is that the FortiGate refuses to accept configuration changes (Statement B). This prevents the system from initiating new processes or allocating additional memory that could lead to a total system crash.
Regarding traffic handling, the behavior is determined by specific "fail-open" settings. For the IPS engine, if the fail-open global setting is enabled, the FortiGate continues to transmit packets without IPS inspection (Statement D). This ensures that network connectivity is maintained even when the system lacks the memory resources to perform deep packet inspection. In contrast, Statement A is incorrect because the system may skip non-essential actions to save memory. Statement C is incorrect because conserve mode is designed to avoid a system halt; the device remains operational and will automatically exit conserve mode once memory usage drops below the Release Threshold (typically 82%).

"To reduce the number of log messages generated and improve performance, you can enable a session table entry of dropped traffic. This creates the denied session in the session table and, if the session is denied, all packets for that session are also denied. This ensures that FortiGate does not have to perform a policy lookup for each new packet matching the denied session, which reduces CPU usage and log generation."
"The CLI command is ses-denied-traffic. You can also set the duration for block sessions. This determines how long a session will be kept in the session table by setting block-session-timer in the CLI. By default, it is set to 30 seconds." Technical Deep Dive:
The correct answers are A and B.
When set ses-denied-traffic enable is configured, FortiGate creates a session-table entry for denied traffic. That means once traffic is denied, subsequent packets that belong to the same denied flow do not need a full policy lookup again. FortiGate can drop them immediately based on the existing denied-session entry. That directly confirms B.
Because FortiGate no longer re-evaluates every repeated denied packet in the same way, the device generates fewer logs and uses less CPU for repeated denied traffic. That is exactly why A is also correct.
Why the other two are wrong:
C is incorrect because block-session-timer 30 means 30 seconds, not 30 minutes. The denied session entry is kept in the session table for that duration.
D is incorrect because these settings do not disable session helpers. They only control how denied traffic is tracked in the session table.
In operational terms, this feature is useful when a host repeatedly retries traffic that FortiGate is already denying. Instead of doing a fresh lookup for every retry, FortiGate caches the denied decision temporarily and drops the repeated packets faster.