Fortinet NSEI_OTS_AR-7.6 - Fortinet NSE I - OT Security 7.6 Architect

The correct answers are C. Vendor OUI and D. Network traffic .

The study guide explicitly separates active/direct profiling methods from passive/non-direct methods and states that “In OT environments, passive methods are preferred over active methods.” It then lists the methods that do not require FortiNAC to interact directly with the device being profiled. Among those methods are “Network traffic: gathered from the infrastructure” and “Vendor OUI: determined by the MAC address gathered from the infrastructure.” That directly matches options C and D .

Options A and B are incorrect because SSH and SNMP are shown in the guide under the direct/active profiling methods. The guide’s point is that passive detection avoids directly scanning or interacting with OT endpoints, since that can negatively affect performance in industrial environments. Because the question specifically asks for passive detection methods, the correct pair is Vendor OUI and Network traffic .

The correct answer is D. You can configure forward domain IDs for each network .

The study guide explains that in FortiGate transparent mode, all interfaces belong to the same broadcast domain, even interfaces with different VLAN IDs , and then states that you can “subdivide into multiple broadcast domains” by configuring set forward-domain < domain_ID > . It also states that “interfaces with the same domain ID belong to the same broadcast domain” and, with multiple forward domains, “traffic arriving on one interface is broadcast only to interfaces in the same forward domain ID.” That is the mechanism used to separate internal networks and confine traffic between network segments.

The other options do not fit this requirement. Universal ZTNA is for application access control, not segmentation between two OT networks. One traffic VDOM does not create segmentation by itself; multiple VDOMs would be needed for that type of isolation. An explicit software switch controls intraswitch traffic inside the same software-switch domain, not segmentation between separate networks like network 1 and network 2. Therefore, the correct way to implement the internal segmentation asked in the question is to assign different forward domain IDs to each network.

The correct answer is C. Application sensor set to monitor on all the FortiGate devices .

The study guide clearly explains that application control is the feature used to identify OT protocols. It states that “application control detects the protocols used in applications like Modbus, IEC 104, and the contents of the telecontrol messages” and also says “You can use application control signatures to detect OT protocols.” It further shows an example where a Modbus application control profile is enabled on a firewall policy “for OT protocol visibility in the monitor status.” This directly matches the requirement in the question, which is to detect OT protocols and increase traffic visibility .

The other options do not fit the requirement as precisely. Device detection is for identifying devices and collecting endpoint information, not for detecting industrial protocols. Inline IDS and IPS are focused more on detecting or blocking attacks, exploits, protocol abnormalities, and known vulnerabilities. While IPS can inspect some OT traffic, the study guide distinguishes it from application control by stating that IPS signatures tend to detect exploits, whereas application control signatures tend to provide protocol detection at various levels . Therefore, the required security sensor for OT protocol detection and traffic visibility is the application sensor in monitor mode .