6.5 OT-Specific Appliances
The previous sections covered general-purpose network appliances: firewalls, IDS/IPS, load balancers, and storage. OT networks require a specialized subset of these appliances — industrial firewalls with deep packet inspection for industrial protocols, and data diodes that enforce 1-way data flow at the hardware level.
Part 6 documents these products in depth. Each Hirschmann product page includes real specifications, configuration guidance, and use cases:
19.1 EAGLE One Firewall Layer 2/3 industrial firewall with Classic Firewall Software. Certified for substation (IEC 61850-3), railway (EN 50121-4), and hazardous locations (ATEX Zone 2).
19.2 EAGLE40 Next-Generation Firewall Stateful + Deep Packet Inspection firewall with HiSecOS. IPSec VPN, OSPF, VRRP, and protocol-specific enforcement modules for EtherNet/IP, Modbus, OPC UA, IEC 104, DNP3, and GOOSE.
19.3 Rail Data Diode Hardware-enforced unidirectional data transfer. The hardware physically eliminates the return path — no software misconfiguration opens the return path.
What Comes Next
Section titled “What Comes Next”OT-specific security appliances complete the infrastructure picture. The next chapter covers wireless networking — 802.11 standards, channels, encryption, and the challenges of deploying wireless in industrial environments.
References
Section titled “References”- Hirschmann. (2024). Belden/Hirschmann Essentials 2024. Belden.