What is an Industrial Firewall?
An Industrial Firewall is a Firewall specifically designed for Operational Technology (OT) and industrial networks. Unlike standard IT Firewalls, an industrial Firewall is optimised for industrial protocols, Real-time communication and network reliability.
Industrial Firewalls protect critical systems such as PLCs, SCADA, Drives, HMIs and Historians from cyberattacks, unauthorised access and misconfiguration.
🧠 How does an industrial firewall work?
- Rule-based packet filtering
- DPI (Deep Packet Inspection)
- Understands industrial protocols and commands
- Can, for example, block “write” commands while allowing “read” traffic
- Zone protection
- Segmentation of the OT network in line with the Zone and Conduits model or Purdue Model
- Separation between Control Network, Engineering Network and DMZ
- Logging & auditing
- Events are recorded for analysis or Security Monitoring
🏭 Application in industrial networks
- Demarcation between IT and OT (e.g. via IDMZ or Datadiode)
- Protection of individual cells or production lines
- Filtering of traffic between PLCs, SCADA and Historian
- Securing external access via VPN or Remote Access
Typical environments:
- Process industry, food, pharma, energy, water, infrastructure (such as tunnels and bridges)
🔍 Industrial vs. Enterprise Firewall
| Feature | Industrial Firewall | Enterprise Firewall |
|---|---|---|
| Protocol support | Modbus, OPC UA, S7, DNP3, Ethernet/IP | HTTP, SMTP, FTP, DNS |
| Real-time behaviour | Support for deterministic networks | Not guaranteed |
| Ruggedness | DIN-rail mount, vibration-resistant | 19” rack or cloud-based |
| Use | OT networks, production installations | IT infrastructure, offices, data centres |
Industrial firewalls are often “hardened” and designed for extreme conditions (temperature, humidity, EMC).
🔐 Security aspects
- Combine with DPI, Access Control, anomaly detection and SIEM
- Implement Least Privilege and “deny by default” policies
- Integrate with User Access Control or RADIUS for authentication
- Use redundancy and High Availability on critical networks
- Configure logging for Audit and compliance (IEC 62443, NIS2)
Note: a misconfigured firewall is just as dangerous as no firewall at all.
📌 In summary
An Industrial Firewall is essential for protecting industrial networks against cyber threats, human error and unauthorised access. They understand industrial protocols, are robustly built and fit within OT architectures.