IoT / OT/ Industrial Firewalls vs Enterprise Firewalls

For a very long, the firewall was a singular concept. Placed at edge of a network, inspected packets, blocked suspicious traffic, and allowed business applications to function. Whether protecting a corporate LAN, data center, or branch office, the same category of firewall—scaled up or down. It was considered sufficient.

Modern networks now include sensors, controllers, cameras, PLCs, meters, medical devices, building automation systems, and industrial robots. These IoT and OT devices behave nothing like traditional IT endpoints. They work on different protocols, follow rigid communication patterns, rarely change, and often run for decades.

This reality has given rise to a new class of security controls: IoT / OT or industrial Firewalls.

What is an IoT / OT firewall and how is it different from an enterprise firewall?

An IoT firewall is designed to protect machines, devices, and deterministic systems. Its core objective is to ensure that devices only perform expected actions and nothing beyond that.

An enterprise firewall, in contrast, is designed to protect users, applications, and data in highly dynamic environments where traffic patterns constantly evolve.

In simple terms:
– IoT firewalls protect behavior
– Enterprise firewalls protect intent

Why can’t enterprise firewalls handle IoT environments effectively?

Enterprise firewalls are optimized for encrypted web traffic, SaaS applications, user identity, and cloud integrations. IoT environments rely on deterministic, machine-to-machine communication using protocols never designed for internet-scale security.

As a result, enterprise firewalls often misclassify IoT traffic as unknown or risky, while IoT firewalls understand the command-level semantics of device communications.

“Availability First” vs. “Confidentiality First” Zero Tolerance for Latency Enterprise firewalls often use Deep Packet Inspection (DPI) and resource-heavy security features that can introduce millisecond delays. In OT, even slight latency can cause a Programmable Logic Controller (PLC) to lose synchronization, leading to production crashes or physical damage.

Standard firewalls act as “bouncers” that may block traffic by default if it looks suspicious. In an industrial setting, blocking a critical safety command because it triggered a false positive could result in catastrophic equipment failure or injury.

Enterprise firewalls were designed to protect known, managed IT assets such as servers, laptops, and users. IoT environments are the exact opposite—massive in scale, largely unmanaged, diverse in device types, and protocol-heavy. As a result, conventional firewalls struggle on multiple fronts.

How do protocol differences influence firewall design?

IoT and OT environments use specialized protocols such as Modbus TCP, DNP3, BACnet, Profinet, EtherNet/IP, IEC-104, OPC-UA, MQTT, and CoAP. These protocols are deterministic, binary, and often unencrypted.

IoT firewalls perform deep protocol inspection, allowing or blocking traffic based on function codes and command types.

Enterprise firewalls focus on HTTPS, HTTP/2, QUIC, VPNs, and SaaS APIs, relying heavily on TLS inspection, application identification, and identity mapping.

How do ASICs and silicon architectures differ?

IoT firewalls use low-power ARM or MIPS-based SoCs, sometimes supported by FPGA-assisted packet engines. They prioritize deterministic latency, low power consumption, and long lifecycle stability.

Enterprise firewalls use custom NPUs, multi-core x86 processors, and dedicated TLS accelerators designed to handle encrypted traffic at massive scale.

How does physical construction differ between Enterprise and OT/ IOT/ Industrial Firewalls ?

 The fundamental difference is where they are expected to be installed. Ruggedised industrial firewalls (Typical of all IoT/ OT Firewalls) are engineered for uncontrolled, harsh field environments, while enterprise firewalls are built for clean, climate-controlled data centres or Server Rooms. The distinction is primarily physical and environmental.

Why do the security models differ philosophically between Enterprise and OT/ IOT/ Industrial Firewalls ? 

IoT firewall security is based on strict whitelisting and assumes that any deviation from known behavior is potentially dangerous.

Enterprise firewall security assumes constant change and focuses on classification, risk scoring, and adaptive policy enforcement.

Active defence vs passive monitoring
Enterprise IT security relies on active intervention—continuous vulnerability scanning, blocking suspicious IPs, quarantining files, and automatically stopping perceived threats. Disruption is acceptable if it protects data.
Industrial OT security follows a passive-first model. Active scanning or aggressive blocking can crash legacy control systems. OT security therefore focuses on listening, baselining, and alerting humans, rather than automated enforcement that could halt production.

Data protection vs Human safety
In enterprise IT, success is measured by the protection of data, finances, and brand reputation.
In industrial OT, success is measured by Safety, Reliability, and Productivity (SRP). The primary objective is preventing physical harm to people, environmental damage, and loss of critical machinery.

How is performance measured differently Enterprise and OT/ IOT/ Industrial Firewalls ?

Enterprise firewalls emphasize throughput, concurrent sessions, and TLS handshakes per second.

IoT firewalls prioritize predictable packet processing, microsecond-level latency, and reliability over raw throughput.

Throughput vs latency

In enterprise networks, performance is throughput-driven. Firewalls are evaluated on Gbps capacity with security features enabled, along with concurrent session handling for users and applications.
In industrial environments, performance is latency-driven. Even millisecond-level delays or jitter can disrupt real-time control systems. High throughput is irrelevant if deterministic response is compromised.

Deep Packet Inspection priorities

Enterprise DPI performance is about scale—identifying thousands of web applications and inspecting encrypted traffic for evolving malware and threats.
Industrial DPI performance is about protocol awareness. The firewall must deeply parse industrial protocols (Modbus, DNP3, etc.) and make command-level decisions—allowing safe “read” operations while blocking dangerous “write” commands—without impacting process timing.

Resilience and failure behaviour

Enterprise firewalls are measured by HA failover times and typically fail-closed, prioritising data security even at the cost of business disruption.
Industrial firewalls are measured by fail-safe reliability. In many OT scenarios, devices must fail-open or bypass on power or hardware failure to ensure machinery remains controllable, as an unexpected shutdown can be unsafe.

Updates and maintenance model

Enterprise firewall performance includes the ability to rapidly and automatically update signatures and AI models to counter new internet threats.
In OT, performance equals long-term stability. Firewalls are expected to run for years with minimal changes, avoiding reboots or updates that could interrupt production.

What happens if the Enterprise firewall used as an OT/ IoT/ Industrial Firewall?

Using an enterprise (IT-centric) firewall in an OT environment introduces operational and  safety risks. The root cause is a fundamental mismatch in priorities: IT optimises for confidentiality, while OT depends on availability and safety. Using an enterprise firewall in an IoT environment can introduce latency, protocol misinterpretation, and operational risk. On the other-side, Using an IoT firewall in an enterprise environment limits visibility into encrypted traffic and user activity.

Operational outages

Enterprise firewalls introduce inspection-related latency (SSL/TLS decryption, DPI), which causes timing jitter in PLC-driven systems. Even micro-delays can trigger automated trips or emergency shutdowns. Unless the deployed enterprise firewall has configurability feature of industrial protocols, they may block legitimate control commands, including emergency stop or safety adjustments—turning a security device into a production risk.

High probability of physical failure

Enterprise firewalls rely on fan-based cooling and standard hardware. In OT environments, dust, heat, grease, vibration, and EMI rapidly degrade these systems, leading to overheating, crashes, or permanent hardware failure.

Security blind spots where it matters most

Enterprise firewalls are perimeter-focused and largely blind to east-west traffic on the factory floor. Once one device is compromised, attackers can move laterally without detection. Most OT attacks exploit decades old Vulnerabilities, while enterprise firewalls focus on modern internet threats, leaving legacy industrial systems exposed.

Severe financial and regulatory impact

Firewall-induced downtime is extremely costly. In OT, a false positive can be more expensive than an attack. Regulations such as India’s NCIIPC / CEA Guidelines now mandate OT-specific controls and Network Segmentation for IT/ OT implementation. Also refer to NSCS/ TTP for the product details, effective 1^st Jan 2026.

Maintenance and safety deadlocks

Enterprise firewalls require frequent patching and reboots. In OT, rebooting may mean stopping the entire plant, so updates are deferred—creating long-term exposure. Enterprise firewalls typically fail-closed. In industrial and life-safety systems, blocking all traffic during a failure can be catastrophic. OT firewalls are designed to  fail-open or bypass, ensuring human control is never lost.

Industry-Specific Use Cases of IoT/ OT Firewalls

Manufacturing & OT

• Protect PLCs, SCADA, robots, and sensors
• Prevent unauthorized command execution
• Smart Manufacturing (Business Continuity)

 Utility and Infrastructure

Power Sector (Grid Stability)

Micro-segmentation of the “Grid Edge”: With India’s 2026 push toward renewable energy, firewalls are deployed to isolate smart inverters and wind turbine sensors from the main control network.

• Water and Wastewater (Public Health)
• Chemical Level Safeguarding:
• Legacy System capacity and cloaking
• Oil and Gas (Physical Safety)
• Pipeline Remote Station Security

NBFC & Banking

Secure ATMs, branch IoT, CCTV, access systems
Enforce RBI cybersecurity and DPDP Act controls

Healthcare

Protect medical devices, imaging systems, nurse stations

Ensure patient safety and regulatory compliance

Few Examples of OT Firewalls of OEMs