NSE4_FGT_AD-7.6 Fortinet NSE 4 - FortiOS 7.6 Administrator Questions and Answers

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.

From the HA configuration shown for HQ-NGFW-1:

set memory-based-failover enable

set memory-failover-threshold 70

set memory-failover-monitor-period 50

set memory-failover-sample-rate 10

set memory-failover-flip-timeout 60

set override disable

set priority 200

From the performance status outputs:

HQ-NGFW-1 memory used is 90% (well above the configured threshold of 70%)

HQ-NGFW-2 memory used is about 48.7% (well below the threshold)

What happens in FortiOS 7.6 with memory-based failover

When memory-based failover is enabled, FortiGate monitors memory utilization. If the unit’s memory usage stays above the configured memory-failover-threshold for the configured memory-failover-monitor-period, the cluster triggers a failover away from the unit under memory pressure.

Threshold = 70%

HQ-NGFW-1 is at 90%, so it violates the threshold.

Monitor period = 50 seconds.

The administrator observed for 55 seconds, which is longer than 50 seconds, so the condition is met for long enough to trigger failover.

The memory-failover-flip-timeout 60 is used to prevent rapid back-and-forth role changes (flapping) after a failover decision; it does not prevent the initial failover from occurring once the threshold breach persists for the monitor period.

When the Application sensor receives traffic on that port, the protocol decoder will try to determine if the received data matches the HTTPS traffic In this case it will not match because it is P2P traffic, so this will class as violation and blocked The protocol decoder also try to determine what type of traffic it is, and even if it could not figure out it is P2P traffic, it still count as a violation because even though it does not know what it is, it knows for fact it is not HTTPS

In FortiOS 7.6, the Antivirus scan master switch in an antivirus profile becomes available only after at least one supported protocol is enabled for inspection.

What the exhibit shows

A new antivirus profile named FTP_AV_Profile

Feature set: Flow-based

Antivirus scan switch is grayed out

All Inspected Protocols (HTTP, SMTP, POP3, IMAP, FTP, CIFS) are currently disabled

Why the Antivirus scan switch is grayed out

In FortiOS antivirus profiles:

The Antivirus scan toggle is a dependent control

It cannot be enabled unless at least one inspected protocol is selected

This prevents enabling AV scanning when there is no traffic type to scan

This behavior is documented in the FortiOS 7.6 Antivirus Profile configuration section.

Once you enable a protocol (for example, FTP), the Antivirus scan switch becomes active and configurable.

Why option B is correct

B. None of the inspected protocols are active in this profile.

All protocol toggles are OFF

Therefore, FortiGate disables (grays out) the Antivirus scan option

This is expected and correct behavior

Why the other options are incorrect

A. Antivirus scan is disabled under Feature visibilityIncorrect. Feature Visibility controls whether Antivirus appears in the GUI, not whether the scan switch is enabled inside a profile.

C. Feature set must be Proxy-basedIncorrect. Antivirus scanning is supported in both flow-based and proxy-based modes.

D. Less than 2 GB RAM does not support Antivirus scanIncorrect. Memory size affects performance and offloading, not basic AV scan availability.

Based on the FortiOS 7.6 Infrastructure and IPsec VPN documentation, Dead Peer Detection (DPD) can be configured in three primary modes: On Demand, On Idle, and Disabled.

On Demand (Default Mode): This mode is specifically designed to minimize unnecessary traffic. In this mode, FortiGate sends DPD probes only when there is no inbound traffic but the FortiGate is attempting to send outbound traffic. Because network communication is typically bidirectional, the absence of inbound traffic while outbound traffic is being sent is a primary indicator of a potentially dead tunnel. This matches the specific requirement described in the question.

On Idle: In this mode, DPD probes are sent if no traffic (neither inbound nor outbound) has been observed in the tunnel for a specific period. It verifies the tunnel status even when the connection is completely idle.

Enabled: In older versions or specific CLI contexts, "Enabled" may refer to periodic DPD, but in the current FortiOS 7.x/7.6 GUI and CLI terminology for Phase 1 settings, the active modes are defined as on-demand or on-idle.

Disabled: In this mode, the FortiGate does not send DPD probes but will still respond to DPD probes sent by the remote peer.

The requirement that the administrator wants probes sent only when there is no inbound traffic (usually implying the FortiGate is sending but not receiving) is the fundamental definition of the On Demand mechanism in the Fortinet curriculum.

In FortiOS 7.6, when a FortiGate is operating in NAT mode, physical interfaces that participate in traffic forwarding (such as LAN and DMZ) must meet certain fundamental requirements.

Correct statements

D. Both interfaces must have IP addresses assigned.

Correct

In NAT mode, FortiGate operates as a Layer-3 device.

Every interface that forwards traffic must have an IP address.

Without an IP address:

The interface cannot participate in routing

Firewall policies cannot be applied correctly

This is a mandatory requirement.

C. Both interfaces must have directly connected routes on the routing table.

Correct

When an IP address is assigned to an interface, FortiGate automatically installs a connected route for that subnet in the routing table.

These connected routes are required so FortiGate:

Knows how to reach the locally attached networks

Can forward traffic between LAN and DMZ

While administrators do not manually create these routes, their presence is required for correct operation.

Why the other options are incorrect

A. Both interfaces must have DHCP enabled and roles assigned.

Incorrect

DHCP is optional; interfaces can use static IPs.

Interface roles (LAN, DMZ, WAN) are administrative/GUI aids, not functional requirements.

B. Both interfaces must have the interface role assigned.

Incorrect

Interface roles affect GUI grouping and some default behavior.

They are not required for NAT mode operation or traffic forwarding.

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. In the IP pool configuration, set end ip to 100.65.0.112.

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. In the IP pool configuration, set type to overload.

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. Multiple Interface Policies is unrelated to IP pool exhaustion and does not solve NAT allocation limits.

C. match-vip affects VIP matching behavior for destination NAT/virtual IP usage and does not address the source NAT pool shortage causing PC3 to fail.

Based on the exhibit and the FortiOS 7.6 SSL/SSH Inspection documentation, the correct answer is C.

Understanding the Exhibit Configuration

In the SSL/SSH Inspection Profile, the following settings are shown:

Inspection method: Full SSL Inspection

Server certificate SNI check: Strict

This setting directly controls how FortiGate validates the Server Name Indication (SNI) provided by the client during the TLS handshake.

FortiOS 7.6 Behavior of “Server certificate SNI check”

FortiOS supports three modes for Server certificate SNI check:

Disable

No validation between SNI and server certificate.

Enable

FortiGate checks SNI against the certificate.

If mismatch occurs, FortiGate may still allow the session with reduced validation.

Strict

FortiGate enforces a strict match.

The SNI must match either the CN (Common Name) or one of the SAN (Subject Alternative Name) entries in the server certificate.

If the SNI does not match either CN or SAN, the TLS session is immediately terminated.

The exhibit clearly shows Strict selected.

Why Option C is Correct

With Strict enabled, FortiGate rejects the TLS connection when:

The SNI does not match the CN, and

The SNI does not match any SAN entry

This results in the connection being closed, not allowed with warnings or fallback behavior.

Therefore:

C. FortiGate will close the connection if the SNI does not match the CN or SAN fields is exactly the documented behavior.

Why the Other Options Are Incorrect

A: FortiGate does not fall back to using the CN for URL filtering when Strict is enabled.

B: There is no “accept with warning” behavior in Strict mode.

D: Incorrect logical condition. FortiGate does not require mismatch with both CN and SAN simultaneously; a mismatch with either valid field set is sufficient to close the connection.

From the exhibits:

A VIP named VIP-WEB-SERVER is configured on WAN (port2) with:

External IP: 100.65.0.200

Mapped (internal) IP: 10.0.11.50

Port forwarding enabled (TCP)

External service port: 443

Map to IPv4 port: 4443

The inbound firewall policy Web_Server_Access is:

From WAN (port2) to LAN (port4)

Destination: VIP-WEB-SERVER

Service: HTTPS

NAT: Disabled (meaning no source NAT is applied)

What happens to the packet

A host 100.65.1.111 sends TCP SYN dst-port 443 to 100.65.0.200.

When FortiGate matches the VIP and forwards traffic to the internal server, FortiGate performs destination NAT (DNAT) based on the VIP:

Source IP is unchanged because policy NAT is disabled:

Source remains 100.65.1.111

Destination IP is translated by the VIP:

Destination becomes 10.0.11.50

Destination port is translated by the VIP port-forward:

Destination port becomes 4443

Therefore, at the time FortiGate forwards the packet to the destination (internal server), it will be:

Source address: 100.65.1.111

Destination address: 10.0.11.50

Destination port: 4443

In FortiOS 7.6, HA cluster heartbeat IP addresses are automatically managed by FortiGate and play a critical role in cluster communication and synchronization.

Correct statements

A. Heartbeat IP addresses are used to distinguish between cluster members.

Correct

FortiGate assigns unique heartbeat IP addresses (link-local addresses in the 169.254.0.0/16 range) to each HA member.

These addresses are used for:

Cluster member identification

Health checks

Synchronization traffic

This allows FortiGate units to uniquely identify and communicate with each other inside the HA cluster.

C. A change in the heartbeat IP address happens when a FortiGate device joins or leaves the cluster.

Correct

Heartbeat IPs are dynamically assigned.

When:

A new FortiGate joins the cluster, or

A member leaves or fails,

FortiGate may reassign heartbeat IP addresses to maintain unique identification among members.

This behavior is documented in the FortiOS HA operation and troubleshooting guides.

Why the other options are incorrect

B. The heartbeat interface of the primary device is always assigned IP address 169.254.0.1.

Incorrect

There is no fixed or guaranteed heartbeat IP (such as 169.254.0.1) for the primary unit.

Heartbeat IP assignment is dynamic, not role-based.

D. Heartbeat interfaces have virtual IP addresses that are manually assigned.

Incorrect

Heartbeat IP addresses are:

Automatically assigned

Link-local

Administrators do not manually configure heartbeat IP addresses.

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. All the SLA targets can be configured.

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 SLA.

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

D. They are applied in an SD-WAN rule lowest cost strategy.

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. They can be measured actively or passively.

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. They rely on session loss and jitter.

Incorrect

SLAs measure packet loss, latency, and jitter.

Session loss is not an SLA metric in FortiOS.

B. They monitor the state of the FortiGate device.

Incorrect

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

According to the FortiOS 7.6 Security Fabric documentation and Study Guide, several conditions must be met for a downstream FortiGate to successfully join a Security Fabric.

First, the Upstream FortiGate IP/FQDN configured on the downstream device must point to the IP address of the interface on the upstream device that is listening for fabric connections. In the provided logical topology, the Fabric Root (HQ-NGFW-1) uses port4 with the IP 10.0.11.254 to connect to the internal segmentation firewalls (ISFWs). Since HQ-ISFW-2 is in the same subnet as HQ-ISFW, it is physically and logically connected to the network segment serviced by port4. Therefore, the current configuration of 10.0.13.254 (which is port6, likely the WAN side) is incorrect, and it must be set to 10.0.11.254 (Statement A).

Second, once the downstream device successfully reaches the upstream device, it enters a Pending state. For security purposes, FortiOS does not allow devices to join the fabric automatically; the administrator of the upstream device (in this case, HQ-ISFW or the root) must manually authorize the new device (Statement C) in the Fabric Management console. Until this authorization is granted, the status will remain "Pending" and no fabric data will be synchronized. Statements B and D are incorrect as SAML settings do not block the initial fabric join, and the management IP should be the local device's IP, not the upstream's IP.

According to the FortiOS 7.6 Study Guide and technical documentation regarding High Availability (HA), the FortiGate Clustering Protocol (FGCP) uses a specific set of rules to elect the primary unit in a cluster. By default, the election order follows: Connected Monitored Ports > HA Uptime > Priority > Serial Number.

However, when the HA override setting is enabled, the election logic is modified to prioritize the administrator-defined priority value over the uptime of the cluster members. In this specific configuration, the election process follows this sequence:

Connected monitored ports: The unit with the most functioning monitored interfaces is preferred.

Priority: The unit with the highest manually configured priority value (e.g., 255) is selected next.

HA uptime: If monitored ports and priority are equal, the unit that has been up in the HA cluster the longest is chosen.

FortiGate serial number: As a final tie-breaker, the unit with the higher serial number is elected.1

Statement A is correct because it reflects the shift where Priority is evaluated immediately after monitored ports, overriding the standard uptime advantage. Statements B and D are incorrect because the FGCP uses HA uptime, not system uptime, for its calculations.