NSE6_SDW_AD-7.6 Exam Dumps - Fortinet Network Security Expert Questions and Answers

For FortiGate to steer traffic using SD-WAN rules, two foundational elements must be in place: available WAN paths (underlay links) and firewall policies that allow traffic to reach the SD-WAN interface.

Underlay links (Option B) are mandatory because SD-WAN operates by selecting among multiple WAN transports (for example, broadband, MPLS, LTE, or IPsec tunnels). These links are configured as SD-WAN members and form the physical or logical paths over which traffic can be steered. Without underlay links, SD-WAN has no paths to evaluate or select.

Firewall policies (Option E) are also mandatory because FortiGate only processes and forwards traffic that is explicitly permitted by a firewall policy. When SD-WAN is enabled, firewall policies must reference the SD-WAN interface or SD-WAN zone as the outgoing interface. If no such policy exists, traffic will not be forwarded and SD-WAN rules will never be evaluated.

Why the other options are incorrect:

Security profiles (Option A) are optional and relate to inspection, not SD-WAN steering.

Overlay links (Option C) are used in specific designs such as ADVPN or hub-and-spoke overlays, but SD-WAN can steer traffic without overlays (for example, DIA-only designs).

Traffic shaping (Option D) is not required for SD-WAN decision-making; it is an optional optimization feature.

Therefore, the two required features that must be configured before FortiGate can steer traffic according to SD-WAN rules are underlay links and firewall policies, which correspond to B and E.

The command shown in the exhibit is:

diagnose sys sdwan service 4 3

This command displays the runtime state of SD-WAN rule ID 3 on the device. The output explicitly shows:

Service(3) which confirms the SD-WAN rule being evaluated is rule number 3

Members(9) which indicates that nine SD-WAN members are associated with this rule

The listed members include multiple IPsec tunnel interfaces such as HUB1-VPN1, HUB1-VPN2, HUB1-VPN3, HUB2-VPN1, HUB2-VPN2, and HUB2-VPN3, which is characteristic of a spoke device connecting to multiple hubs in a hub-and-spoke ADVPN topology, as defined in the FCSS SD-WAN 7.6 architecture.

Option B is incorrect because, although members are listed under different interfaces, the output does not indicate SD-WAN zones. Zones are shown only in configuration output, not in this diagnostic command.

Option C is incorrect because this is not a hub device. The presence of multiple hub tunnels as SD-WAN members indicates a spoke role. Additionally, the output does not confirm the number of established ADVPN shortcuts.

Option D is incorrect because the output clearly references SD-WAN rule 3, not rule 4, and it does not state that exactly three shortcut tunnels are allowed.

Therefore, the correct conclusion is that this is a spoke device and SD-WAN rule 3 is configured with nine members, which matches option A.

Before FortiGate can steer traffic according to SD-WAN rules, certain configuration elements must be present. The guide states:

"SD-WAN is not a standalone feature and interacts with several fundamental FortiGate configurations. Specifically, you must: (1) Define the interfaces (physical, VLAN, or IPsec) that will act as SD-WAN members, (2) Create firewall policies to allow traffic to be steered by SD-WAN, and (3) Set up routing so that traffic has valid routes via SD-WAN members. Without these, SD-WAN rules will not be able to match or steer any traffic."

Security profiles and traffic shaping are not mandatory for basic SD-WAN steering but can be layered on for enhanced security and QoS once foundational elements are present.

From the SD-WAN Zones view in the FortiGate GUI:

virtual-wan-link is the default SD-WAN zone. This zone is system-defined and cannot be deleted, which makes option A incorrect.

The WAN2 zone is displayed without any expandable members beneath it, indicating that no SD-WAN members are currently assigned to the WAN2 zone. This directly supports option B.

A zone can be deleted only if it has no members and is not system-defined, but the exhibit does not indicate that WAN1 is eligible for deletion. Therefore, option C cannot be concluded from the information shown.

In FortiOS SD-WAN, an SD-WAN member can belong to only one SD-WAN zone at a time. A member such as B-125 cannot be assigned to both the WAN3 zone and the Test zone simultaneously, which makes option D incorrect.

This is because the setting minimum-sla-meet-members = 2 requires at least two SD-WAN zone members (in this case, HUB2-VPN1, HUB2-VPN2, and HUB2-VPN3) to pass the defined SLA health check (HUB1_HC) before the FortiGate will establish ADVPN shortcuts. If fewer than two members meet the SLA, shortcuts will not be created.

The diagnose output lists SD-WAN members 4(HUB1-VPN1), 5(HUB1-VPN2), 7(HUB2-VPN1), 8(HUB2-VPN2), and 9(HUB2-VPN3). It does not include member 6 (HUB1-VPN3). From the template, HUB1-VPN3 is installed only on branch2_fgt and branch3_fgt - not on branch1_fgt. Therefore, the output must be from branch1_fgt.

In FortiOS 7.6, when a Performance SLA probe mode is set to Prefer Passive, FortiGate attempts to measure link performance using passive monitoring first, based on real user traffic. Only when passive monitoring is not possible does FortiGate temporarily fall back to active probing.

With Prefer Passive, FortiGate passively monitors TCP traffic flowing through the SD-WAN member to calculate SLA metrics such as latency, jitter, and packet loss. This behavior directly matches option A.

During passive monitoring, FortiGate relies on observed traffic to infer link health. Because no synthetic probes are sent, a completely dead link (with no traffic passing) cannot be detected by the SLA during passive mode. As a result, dead members may not be immediately detected, which makes option D correct.

Option B is incorrect because there is no fixed 3-minute timer defined in FortiOS 7.6 that forces a return from active probing back to passive monitoring.

Option C is incorrect because passive SLA monitoring is based on TCP traffic, not ICMP traffic. ICMP is used for active probing, not passive monitoring.

Option E is incorrect because traffic subject to passive SLA monitoring cannot be offloaded to hardware. Passive SLA measurement requires software inspection of packets, which prevents NPU offloading.

Therefore, the two correct observable impacts of configuring the probe mode as Prefer Passive are A and D.

The SD-WAN rule (config service edit 1) is configured with set mode priority. This means the rule selects the best interface based on a defined performance metric, as opposed to a simple static priority or SLA. The event log (image_41cfb5.png) shows Metric latency and Message Service prioritized by performance metric will be redirected in sequence order. This indicates that the rule is using latency to determine the preferred member. Given that the log message is about a change, and the most logical reason for a change in a priority mode is that a different member is now the best performer, it implies that the latency on port2 has become lower than that on port1.

The log message Service prioritized by performance metric will be redirected in sequence order confirms that FortiGate is changing the member being used for this service. Because the mode is priority, FortiGate dynamically selects the member that currently meets the best performance criteria, which in this case is latency. The log implies a new member has been selected as the most optimal, and with the default configuration, the members are sorted based on their performance, so the outgoing interface list is effectively updated to prefer the new best-performing member (port2).