Security & connectivity
Why should an older CNC control not sit directly on the business network?
Updated
OT-MaxDNC-MaxNetwork segmentation
Direct answer
Legacy controls may depend on unsupported operating systems and older protocols that cannot be hardened like current IT endpoints. Give them only the communication they need through a private segment, DNC server, or hardened gateway. The objective is to preserve production capability without granting the control broad network reachability.
Practical checkpoint
From the CNC segment, verify that only the specifically authorized DNC, data, time, or support endpoints can be reached.