NSE4_FGT_AD-7.6 Practice Questions

From the exhibits:

The firewall policy has NAT enabled and is configured to Use Dynamic IP Pool.

The selected IP pool (Internet-pool) is configured as:

Type: One-to-One

External IP Range: 100.65.0.110–100.65.0.111 (only two public IPs)

PC1 and PC2 can access the internet because each one-to-one NAT mapping consumes one public IP from the pool. When PC3 is added, there is no third public IP available in the pool, so FortiGate cannot allocate a one-to-one mapping for PC3 and the session fails.

FortiOS behavior here is standard: with one-to-one IP pools, the available pool size limits how many distinct internal sources can be translated concurrently (depending on allocation and sessions), and a pool with only two IPs will not reliably support three separate hosts needing translations.

Therefore, the administrator can fix this in two valid ways:

B.  

This expands the pool by adding an additional public IP address, making three public IPs available (.110, .111, .112), so PC3 can be assigned an address for one-to-one NAT.

D.  

Changing the pool type to overload enables PAT (many-to-one), allowing multiple internal hosts (PC1, PC2, PC3) to share the pool address(es) using different source ports. This removes the “one public IP per internal host” limitation inherent to one-to-one pools.

Why the other options are not correct:

A.  

C.  

In FortiOS 7.6, SD-WAN Performance SLAs are used to measure link quality and influence SD-WAN rule decisions. The following three statements are true.

C.  

True

SD-WAN Performance SLAs allow administrators to configure:

Latency

Jitter

Packet loss

Mean Opinion Score (MOS) (for voice)

Threshold values for these metrics are fully configurable per SL

A.  

This is explicitly documented in the SD-WAN Performance SLA configuration section.

D.  

True

Performance SLAs are commonly used with the Lowest Cost (SLA-based) strategy.

In this strategy:

FortiGate selects the lowest-cost link that meets the SLA requirements.

If a link violates the SLA, it is excluded from selection.

E.  

True

FortiOS supports:

Active probing (synthetic probes such as ping/HTTP)

Passive measurement (based on real traffic statistics)

Administrators can choose how SLAs are measured depending on the deployment and requirements.

Why the other options are incorrect

A.  

Incorrect

SLAs measure packet loss, latency, and jitter.

Session loss is not an SLA metric in FortiOS.

B.  

Incorrect

Performance SLAs monitor link quality, not FortiGate system health or device state.

From the exhibits:

System performance output

Memory used: 90%

Free memory: ~5%

Default memory thresholds (FortiOS 7.6)

memory-use-threshold-green 82%

memory-use-threshold-red 88%

memory-use-threshold-extreme 89%

Because memory usage (90%) exceeds the extreme threshold (89%), the FortiGate enters conserve mode.

Effects of conserve mode (FortiOS 7.6 – verified)

B.  

Correct

When memory usage exceeds the red/extreme threshold, FortiGate automatically enters conserve mode.

This is exactly the condition shown in the system performance output.

D.  

Correct

Even in conserve mode:

Administrators can still log in (GUI, SSH, console)

Configuration changes are allowed

FortiGate does not lock configuration access during conserve mode.

This behavior is explicitly documented in the FortiOS 7.6 Conserve Mode section.

Why the other options are incorrect

A.  

Incorrect

Network access (GUI/SSH) is still available in conserve mode unless otherwise restricted.

Console-only access is not a conserve-mode requirement.

C.  

Incorrect (as a general statement)

FortiGate may drop or bypass new inspection-required sessions depending on fail-open/fail-close settings.

It does not universally drop all new sessions, so this statement is not always true.

"Also, advanced mode supports nested or inherited groups; that is, users can be members of subgroups that belong to monitored parent groups." "In advanced mode, you can configure FortiGate as an LDAP client and configure the group filters on FortiGate. You can also configure group filters on the collector agent."

Collector Agent Advanced Mode provides deeper integration between FortiGate, LDAP, and Active Directory, compared to standard mode.

Key features of Collector Agent Advanced Mode

B.  

Correct

In advanced mode:

FortiGate directly queries LDAP/AD

User group filters are configured on FortiGate, not only on the Collector Agent

This allows more flexible and scalable user/group-based policies

D.  

Correct

Advanced mode supports:

Nested AD groups

Inherited group memberships

This is one of the primary reasons advanced mode is used in complex AD environments

Why the other options are incorrect

A.  

Incorrect.

Security profiles can be applied to users or groups, depending on policy configuration.

C.  

Incorrect.

NetBIOS naming is associated with standard mode

Advanced mode typically uses LDAP DN-based identification

Based on the diagnose debug rating output provided in the exhibit and the standard behavior of the FortiGuard connection mechanism in FortiOS 7.6:

Weight Calculation (Statement A is True):

In FortiOS, the rating server selection process uses a weight-based system.

According to official documentation, the weight increases with failed packets (lost responses) and decreases with successful packets.

This mechanism ensures that servers with poor reliability are penalized by having higher weights, effectively pushing them to the bottom of the preference list.

Default Port Communication (Statement D is True):

The exhibit explicitly shows the communication is using HTTPS on port 8888.

In FortiOS 7.6 (and legacy versions like 6.2/6.4), FortiGuard filtering supports specific protocols and ports: HTTPS on ports 443, 53, and 8888, where 8888 is considered a default port for FortiGuard queries.

Ports 53 and 8888 are standard for both UDP and TCP/HTTPS FortiGuard communications to avoid common firewall blocks on standard web ports.

Why other options are incorrect:

Statement B (Unreliable protocols): While you can configure UDP (which is unreliable), the exhibit specifically shows HTTPS is being used, which is a reliable (TCP-based) protocol.

Statement C (DNS lookup): In the "Flags" column of the server list, a server found via DNS lookup would be marked with the "D" flag. The exhibit shows the flag as "I" (indicating the last INIT request was sent to this server) and a numeric "2," but the "D" flag is absent. Additionally, the IP 10.0.1.241 is a private address, suggesting it is a manually configured FortiManager or local override server rather than a public server found via global DNS lookup.

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%).

The exhibit shows a FortiGate UTM application control log with fields such as:

type="utm"

subtype="app-ctrl"

action="block"

policyid=1

appid=30220

appcat="Video/Audio"

service="HTTP"

apprisk="elevated"

This is a forward traffic security log, generated by Application Control applied to a firewall policy.

Why the correct answers are C and D

C.  

Correct.

FortiOS logs can be viewed and filtered in:

Log & Report → Forward Traffic

Administrators can filter logs using fields such as:

Policy ID / Policy UUID

Application name (app)

Application ID (appid)

The log entry clearly includes application-related fields, making filtering by policy and application a valid and documented way to view these logs.

D.  

Correct.

The log is a UTM Application Control log for traffic passing through a firewall policy.

Such logs are displayed under:

Log & Report → Forward Traffic

This is the standard and correct location to view application control, web filter, IPS, and other security profile logs related to user traffic.

Why the other options are incorrect

A.  

Incorrect.

Implicit deny policies do not generate UTM forward traffic logs like the one shown.

Application control logs are generated only by explicit firewall policies with security profiles enabled.

B.  

Incorrect.

diagnose log test is used to test log connectivity and log settings, not to view historical log entries.

It does not display traffic or UTM logs.