OT Security Architecture Review
Review the security boundaries protecting your operations
Architecture determines how far an incident can spread. An architecture review examines how your OT networks are structured, where trust boundaries sit and whether the communication paths that cross them are understood and controlled.
- Sheet
- Service sheet
- Service
- OT Security Architecture Review
- Scope areas
- 11
- Potential deliverables
- 4
- Engagement
- Scoped to you
In short
An OT security architecture review evaluates the design of industrial networks and the controls at their boundaries — segmentation, firewalls, the industrial DMZ, remote access and monitoring — to identify where the design allows more connectivity or trust than operations require.
The challenge
Network designs that were sound when commissioned drift over time. Temporary connections become permanent, firewall rules accumulate, and new systems are attached wherever a port is available. Documentation describes the intended design, not the current one.
The result is often a flat network in practice, even where segmentation exists on paper.
Scope and activities
Areas typically reviewed:
IT/OT boundaries
Where enterprise and control networks meet, and what is permitted between them.
Network segmentation
How the OT network is divided and whether segmentation matches process and criticality.
Security zones and conduits
Zone definitions, trust levels and the conduits that connect them.
Firewall and communication flows
Rule sets and documented flows compared with what operations need.
Industrial DMZ design
Placement of shared services such as historians, patch and antivirus servers and jump hosts.
Remote access
Vendor and engineering access architecture, authentication and session control.
Management networks
Out-of-band and device management access paths.
Monitoring architecture
Where network and host monitoring is, or could be, placed.
Redundancy and resilience
How redundant paths and failover affect security boundaries.
Identity services and dependencies
Domain services, time sources and other shared dependencies that cross zones.
Backup and recovery architecture
Where backups are stored and whether they survive an incident.
Potential deliverables
Final deliverables depend on the agreed engagement.
- Architecture observationsDocumented as-found design with noted discrepancies.
- Architecture findingsWeaknesses with affected zones, flows and rationale.
- Target architecture recommendationsA practical reference design for your environment.
- Prioritized improvement planChanges sequenced around outages and dependencies.
Engagement approach
Collect
Gather drawings, firewall exports, remote access designs and system descriptions.
Model
Build an as-found view of zones, boundaries and flows with your engineers.
Review
Assess the design against good practice and your security requirements.
Recommend
Propose a target architecture and the steps to get there.
Walk through
Review findings with engineering and network teams and refine the plan.
Assumptions and limitations
- The review is based on documentation, configuration exports and discussions.
- Live network testing, scanning or configuration changes are not included unless agreed separately.
- Recommended changes must be validated and implemented through your change management process.
What helps us get started
- Network and architecture drawings
- Firewall rule exports and remote access configuration
- List of systems that communicate across zones
- Network and control system engineers for walkthroughs
Sensitive material is exchanged only after an engagement is agreed, using a method we agree with you — never through the website form.
Questions about OT Security Architecture Review
What is an industrial DMZ?
An industrial DMZ is a buffer network between enterprise IT and OT. Shared services such as historian replicas, patch servers and remote access gateways sit there, so that no traffic needs to pass directly between IT and control networks.
Do you test our firewalls?
Not by default. The review analyzes designs and configuration exports. Technical testing can be added as a separate, planned activity if required.
What are zones and conduits?
Zones group assets with similar security requirements; conduits are the controlled communication paths between them. The concept comes from IEC 62443 and is a practical way to describe segmentation.
Related pages
From the blog
Insights on OT Security Architecture Review
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Architecture8 min
Zones and conduits in practice: segmentation that survives reality
Segmentation diagrams often look perfect and behave very differently. A practical method for zones and conduits that match how your site really works.
Read the article -
Regulation6 min
Preparing for Saudi NCA OTCC: a practical readiness guide
OTCC extends the NCA's Essential Cybersecurity Controls into industrial control systems. Here is how to scope, assess and evidence readiness.
Read the article -
Best practice5 min
Secure remote access for OT vendors: a 2026 baseline
Remote access remains one of the most common routes into OT. A clear, achievable baseline for vendor and engineering access in 2026.
Read the article
Talk to us about OT Security Architecture Review
Share your objectives and constraints. We'll help you define a scope that fits your operations.