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← The OT Field Guide
03

You cannot secure what you have not walked

Ground every finding in field reality: verify assets, connections and undocumented links on site.

5 min readInteractive figureISA/IEC 62443-2-1NIST SP 800-82r3
Interactive figure
The plant on the drawing, and the plant on the floor
ENTERPRISESUPERVISORYCONTROLERPOffice LANFirewallHistorianSCADAEWS-02HMI-07PLC-201PLC-203SIS-02
Assets
10
on the register
Paths
9
on the drawing
Bypasses
0
known
Switch to After ThePlantWalk to see what a desk review never finds.

Toggle between the network on the drawing and what a walkdown actually finds.

The drawing is not the plant

Network diagrams and asset registers age the moment a turnaround ends. A vendor leaves a cellular modem in a cabinet for remote support. A contractor bridges two networks with a laptop. A spare switch is patched in to solve an urgent problem and never removed.

None of these appear on paper, and all of them change your exposure. Desk-based assessments and questionnaires cannot see them.

ThePlantWalk

Our senior practitioners walk the plant alongside your engineers, cabinet by cabinet and asset by asset. We verify what is installed, how it is connected and what is reachable, combining physical inspection with passive network visibility that does not disturb the process.

The result is a living asset inventory and a map of flows, the foundation for every risk assessment, segmentation design and monitoring decision that follows.

Takeaways
  1. 01Treat registers and drawings as hypotheses to verify.
  2. 02Look for the undocumented: modems, bridges, unmanaged switches, shared laptops.
  3. 03Use passive methods on live networks.