OT NETWORK
FIREWALL
Your IT Firewall Was Not Built for OT
Operational technology networks operate on protocols like Modbus, DNP3, EtherNet/IP, and PROFINET that standard IT firewalls cannot inspect or understand. A firewall that doesn’t recognize what it’s seeing can’t protect what’s behind it. Deploying an OT-unaware firewall creates a dangerous illusion of security.
Most industrial environments have grown organically over decades—PLCs, RTUs, HMIs, and historian servers operating with flat network topologies and no segmentation between zones. A single compromised endpoint in an unsegmented network can spread laterally to your most critical assets within minutes.
Legacy OT devices cannot be patched without operational downtime, and in many cases cannot be patched at all. Virtual patching at the firewall level provides critical protection for vulnerable assets without requiring any changes to the devices themselves—buying time while maintaining uptime.
What a next-gen OT Firewall should do
OT Protocol Deep Packet Inspectionr
Inspect and enforce policies at the application layer for industrial protocols including Modbus, DNP3, EtherNet/IP, and PROFINET. Block unauthorized commands and abnormal values before they reach your control systems.
Zone-Based Network Segmentation
Enforce the Purdue Model by creating security zones across IT/OT boundaries, DMZ layers, and field device networks. Control and audit all traffic flows between every zone with granular, policy-driven access controls.
Virtual Patching for Legacy Assets
Protect unpatched PLCs, RTUs, and HMIs by blocking exploitation attempts at the network perimeter. Maintain security coverage for end-of-life devices that cannot be updated without operational disruption.
Industrial Firewall Features That Matter in OT
OT Asset Discovery & Visibility
Automatically identify and classify all devices on your OT network—PLCs, HMIs, RTUs, switches, and more—without active scanning that could disrupt sensitive operations.
Auto-Generated Policy Recommendations
Generate baseline firewall policies from observed traffic patterns, reducing manual configuration effort and the risk of misconfiguration in complex industrial environments.
Purdue Model Enforcement
Apply architectural controls aligned with ISA/IEC 62443 zone and conduit requirements, ensuring proper separation between enterprise, supervisory, and field device layers.
Failsafe & High-Availability Design
Deploy in fail-open or fail-closed modes to match your operational risk tolerance. Redundant configurations ensure firewall failures never cause process disruptions.
