Manufacturing OT
A plant network designed around the Purdue model so control systems stay reachable without becoming a doorway into the business.
The Purdue model organizes a manufacturing environment into levels: Level 0 field instruments, Level 1 controllers, Level 2 local operator interfaces, Level 3 manufacturing operations and the control center LAN, Level 4 enterprise business systems, and Level 5 the internet. The design goal is that a problem in a higher level cannot directly reach a lower level, so a compromised office PC cannot send commands to a PLC.
Purdue model
The control network, industrial DMZ and enterprise are stacked so a compromised office PC cannot reach a PLC — and production data still reaches the people who need it.
Industrial control systems were not designed for the internet. They often run old operating systems, rely on flat addressing, and assume every device on the network is trusted. When they are connected to the same network as the office, ransomware, misconfigured updates, or a single malicious email can stop production.
The Purdue model solves this by separating zones and only allowing traffic through controlled, documented paths.
The DMZ is the only place where business and control systems are allowed to meet. A historian replica in the DMZ lets ERP and reporting read production data without touching the live SCADA server. A patch server in the DMZ can push updates to isolated equipment. A jump server lets vendors reach the device they support without a tunnel to the rest of the plant.
Common questions
Yes. The model is about network zones and firewall rules, not about replacing controllers. The hard part is usually discovering what is actually on the floor and deciding what each device really needs to talk to.
No. The model is a reference, not a mandate. A small shop may collapse some levels, but the principle remains: separate control from office and make the path between them intentional.
We review your network, security posture, cloud tenant and recovery plan, then hand you a plain-language report of what we found and what it means for the business.
