FortiGate for application control and intrusion prevention system (IPS): In the control area zones, FortiGate can provide critical security measures such as application control and intrusion prevention. This helps detect and prevent unauthorized activities and threats targeting the OT network.
FortiNAC for network access control: FortiNAC can be used to enforce network access policies, ensuring that only authorized devices and users can access specific zones within the control area, thereby reducing the risk of unauthorized access or breaches.
FortiSIEM for security incident and event management: FortiSIEM provides centralized monitoring and analysis of security incidents and events across the OT environment. It helps to identify potential threats, improve visibility, and ensure quick responses to security incidents.

The current configuration assigns priority 2 to the
IEC.60870.5.104_Information.Transfer.C.BO.NA.1 application signature and sets it to Block.
Priority 1 contains broader IEC.60870.5.104_Information.Transfer entries set to Monitor, which overrides the block action due to higher priority. To ensure that the C.BO.NA.1 signature is blocked, it must have higher priority than the general monitoring rule.