NSE6_OTS_AR-7.6 Certification Exam Guide + Practice Questions Updated 2026

Explanation:
The correct answer is C. EtherCAT.
The study guide states that for industrial Ethernet protocols, “such as Ethernet/IP and Modbus/TCP, you can use VLANs to segment your physical LAN into multiple logical LANs.” This directly confirms that Ethernet/IP and Modbus/TCP support VLAN-based segmentation in the OT context.
By contrast, the guide explains that “EtherCAT skips layers 3 to 6 to deliver real-time communication” and describes it as an “Open-Software Modified-Ethernet” approach. Because it does not operate like the standard Ethernet/IP model used for normal VLAN-based segmentation, EtherCAT is the protocol identified here as not supporting VLANs in the way Ethernet/IP and Modbus/TCP do.
So, based on the study guide comparison, the verified answer is EtherCAT.

Explanation:
The correct answers are B. IPS on FortiGate_Level5 and C. Virtual patching on FortiGate_Level2.
The study guide explains that “the first line of defense is securing the IT side of your network” and that FortiGate should be placed to protect ICS environments and stop threats from propagating from IT into OT. It also states that IPS improves OT security because “today’s threat landscape requires IPS to block a wider range of threats and improve OT security” and that in IPS mode, vulnerable devices are protected. This makes FortiGate_Level5, at the upper boundary near the DMZ and external connectivity, the correct place to implement IPS as a primary protection control.
The study guide also states in the Purdue model section that “Level 2 consists of the processes and programs that control the PLCs, RTUs, and IEDs found at Level 1” and that “it is necessary to segment, or even microsegment, these servers with firewall segmentation, along with policies that include application control and virtual patching.” In addition, the virtual patching section says “Virtual patching protects OT devices that have not yet been updated against vulnerability exploits” and applies when traffic related to the vulnerable device reaches the firewall policy. Since FortiGate_Level2 sits between the process network and the control network, it is the right enforcement point for virtual patching to protect the PLC-side assets.
Option A is not one of the best answers because offline IDS only detects and logs attacks; the guide says “no traffic flows through FortiGate” in offline IDS mode, whereas IPS can actually block threats.
Option D is also not the best answer because OT signatures are enabled within the IPS framework, but the stronger control explicitly described for this design is to deploy IPS at the upper boundary and virtual patching closer to vulnerable OT devices.

Explanation:
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.

Explanation:
The correct answer is A. FortiGate queries FortiGuard servers. The study guide explains the device detection process very clearly: “First, FortiGate attempts to detect the devices based on the information in the local device database (CIDB). If FortiGate cannot detect the devices locally, it queries the FortiGuard servers by sending data about the unknown devices to the FortiGuard servers. In response, the FortiGuard servers provide additional information about those devices.” This directly answers the question and shows that querying FortiGuard is the next step after local detection fails.
Option D is incorrect because the guide says FortiGate checks the local device database (CIDB) first, before this next step.
Option B refers more to FortiNAC-style profiling logic, not FortiGate’s OT device detection flow.
Option C is also incorrect because service connectors are not described here as the immediate follow-up step for unknown local device detection. The study guide specifically identifies FortiGuard servers as the next destination for device identification assistance