Operational Technology (OT) is the backbone of modern industry — the hardware and software that keep physical processes running safely, efficiently, and continuously. From the automated machinery in factories to the control systems behind power grids and water treatment plants, OT underpins the critical infrastructure that keeps the world moving.
But as these systems become more connected to digital networks, gaining a deeper understanding of operational technology and its relationship to traditional IT systems has become essential for both business leaders and engineers.
So, what is OT?
Operational Technology (OT) refers to the systems, networks, and devices that monitor and control physical processes, machinery, and infrastructure. These systems are designed to ensure that industrial operations — such as manufacturing, energy production, logistics, and utilities — run safely and continuously.
Examples of Operational Technology environments
OT systems can be found across a range of critical and industrial sectors. Some of the most common include:
Manufacturing
- Assembly lines, robotic systems, and automated packaging rely on OT for precise control and continuous operation.
Energy
- Power generation, oil and gas refineries, and renewable energy farms depend on OT systems for safe, efficient control of turbines, compressors, and grid management systems.
Utilities
- Water treatment plants, sewage systems, and electrical grids use OT to manage flow rates, pressure, and chemical dosing — ensuring public services remain safe and reliable.
Logistics and transport
- Ports, airports, and warehouse automation systems use OT to control cranes, conveyor belts, and vehicle routing, optimising throughput and safety.
Each of these OT environments presents its own security challenges — especially as organisations introduce remote connectivity, IoT devices, and cloud-based monitoring.
How OT differs from IT
Information technology (IT) deals primarily with data and communication systems. In contrast, OT focuses on controlling real-world outcomes. So whilst IT is concerned with storing files and documents, sending emails, and managing customer data, OT is focused on things like starting a pump, adjusting a conveyor belt’s speed, or opening a valve in a refinery.
In short, IT manages information; OT manages action.
OT and IT were built with very different priorities in mind.
| Aspect | Operational Technology (OT) | Information Technology (IT) |
| Primary Function | Control and monitor physical processes | Manage and process data |
| Downtime Tolerance | Near-zero (continuous uptime is critical) | Some downtime acceptable |
| Typical Environment | Industrial sites, factories, plants, utilities | Offices, data centres, cloud systems |
| Primary Concern | Safety and reliability | Data confidentiality and integrity |
| Update Cycles | Infrequent; systems may run for decades | Regular updates and patches |
| Vulnerabilities | Legacy systems, limited visibility, vendor dependencies | Phishing, malware, data breaches |
But the two worlds are increasingly converging. And whilst OT networks were traditionally isolated — “air-gapped” — from corporate IT networks, the rise of Industry 4.0 has seen the two become much more connected for remote monitoring, analytics, and automation, blurring the line between the two domains.
What are OT systems?
An OT system is a combination of hardware devices and software designed to monitor and control physical processes. Together, these systems form the core of industrial operations.
In a typical OT system, you’re likely to find devices like:
- Programmable Logic Controllers (PLCs): Industrial computers that automate specific processes, such as opening valves or starting motors.
- Supervisory Control and Data Acquisition (SCADA) systems: Centralised software that gathers data from sensors and controls processes across multiple sites.
- Sensors: Devices that collect data on temperature, pressure, vibration, flow, or position.
- Actuators: Mechanisms that convert digital commands into physical actions, such as moving a valve or starting a pump.
- Human–Machine Interfaces (HMIs): Screens or control panels that allow operators to monitor and interact with OT systems in real time.
Together, these elements form complex OT environments that keep industrial operations running 24/7 — often in harsh or remote conditions.
What are OT networks?
An OT network is the way in which systems and devices — such as sensors, controllers, actuators, and SCADA systems — are connected so they can communicate and coordinate effectively across an industrial environment.
It’s like the nervous system of an industrial operation: transmitting commands, measurements, and alerts between the components that keep physical processes running safely and efficiently.
Unlike IT networks, which are optimised for data speed and bandwidth, OT networks prioritise determinism — the guarantee that communication between devices happens within a precise and predictable timeframe.
In a factory or power plant, milliseconds matter. A delay in sending a command to shut down a motor or open a valve could lead to safety incidents, product defects, or costly equipment damage.
Deterministic communication ensures that every instruction arrives exactly when it’s needed — not just as fast as possible. This makes OT networks highly reliable, but also less flexible than IT systems.
The role of communication protocols
To make all these devices work together, OT networks rely on industrial communication protocols — the standardised “languages” that define how information is formatted, transmitted, and received between machines.
These protocols ensure interoperability between different types of equipment, even from multiple vendors, and are tailored for the specific needs of industrial automation: reliability, timing, and safety.
Here are some of the most widely used OT network protocols:
Modbus
- One of the oldest and most widely used industrial protocols, Modbus is simple and robust.
- It allows controllers and sensors to exchange data using a master–slave structure, where one device (the master) requests information and the others (slaves) respond.
- Modbus is still common in manufacturing, energy, and utilities because it’s easy to implement — though it lacks built-in encryption or authentication, which creates potential security risks in modern connected environments.
PROFINET
- Developed by Siemens, PROFINET is a modern, Ethernet-based protocol widely used in factory automation.
- It supports real-time data exchange between controllers, sensors, and actuators, making it ideal for high-speed, time-critical industrial processes.
- PROFINET is deterministic, highly scalable, and integrates easily with IT systems — but this connectivity also increases the need for strict network segmentation and cybersecurity controls.
EtherNet/IP
- Despite its name, EtherNet/IP (Ethernet Industrial Protocol) is not the same as standard office Ethernet.
- It’s designed specifically for industrial use, enabling devices like PLCs and HMIs to communicate over standard Ethernet infrastructure using the Common Industrial Protocol (CIP).
- EtherNet/IP supports both control and information data, making it popular in manufacturing environments that need close integration between OT and IT networks.
DNP3
- Short for Distributed Network Protocol, DNP3 is common in utilities — particularly electric power, water, and wastewater systems.
- It’s designed to provide reliable communication over long distances and in noisy environments, such as remote substations.
- DNP3 includes features like time stamping and error checking, making it more robust and secure than some older protocols, though additional cybersecurity layers are still recommended.
Many OT networks have evolved over decades, combining modern Ethernet-based technologies with older serial systems and proprietary vendor protocols.
This patchwork of legacy equipment can make integration and visibility difficult, and can expose vulnerabilities if not properly segmented and secured.
Understanding your OT network in this broader context — including how protocols interact and how data flows across systems — is essential for planning safe connectivity with IT networks, cloud platforms, or remote monitoring tools.
The role of OT in Industry 4.0
Industry 4.0 builds on earlier waves of industrial innovation (mechanisation, electrification, and digitisation) by connecting machines, systems, and data through advanced technologies such as the Industrial Internet of Things (IIoT), artificial intelligence (AI), machine learning, and cloud analytics.
The result is a new generation of smart factories and connected infrastructure, where operational data flows freely between physical equipment and digital platforms to improve efficiency, reliability, and decision-making.
As industries embrace Industry 4.0, the line between OT and IT continues to blur. So, it’s increasingly common to find modern OT environments connected to:
- IoT and IIoT devices for real-time data collection
- Data analytics platforms for predictive maintenance and performance optimisation
- Cloud services for remote monitoring and automation
- Artificial intelligence systems that support process optimisation and energy efficiency
This digital integration offers huge efficiency and safety benefits — but it also introduces new vulnerabilities that traditional OT systems were never designed to handle.
Why OT security matters
In the past, OT systems were isolated and considered “safe by design.” Today, connectivity has changed that.
A successful cyberattack on an OT system can have real-world physical consequences:
- Production downtime
- Equipment damage
- Environmental harm
- Safety hazards
- Regulatory and reputational fallout
In critical industries, even a few hours of downtime can result in millions of pounds in lost revenue — or endanger lives.
That’s why OT security is now a board-level issue, not just a technical one.
Common risk areas in OT environments
All OT environments are different, and the only way to fully establish risk areas in an OT environment is to run a full OT risk assessment. But there are some risk areas which are commonly found in many OT set-ups:
- Legacy Systems – Outdated OT technology that lacks modern security features.
- Unsegmented Networks – Flat architectures that allow attackers to move laterally.
- Third-Party Access – Vendors or contractors connecting remotely without secure controls.
- Poor Visibility – Lack of real-time monitoring and asset inventory.
- Insecure Protocols – Legacy industrial protocols without encryption or authentication.
- Human Error – Operators using weak passwords or bypassing safety procedures.
- Converged IT/OT Networks – Insecure integration between corporate IT and operational systems.
Best practices for securing OT environments
To protect critical operations, organisations should take a structured framework approach to OT cybersecurity:
- Network Segmentation: Separate OT networks from IT and external networks to limit the spread of potential attacks.
- Continuous Monitoring: Use intrusion detection systems tailored for OT protocols to spot unusual activity.
- Secure Remote Access: Apply multi-factor authentication and session monitoring for vendors or engineers.
- Asset Inventory: Maintain an up-to-date map of all OT systems, devices, and firmware versions.
- Patch Management: Develop a safe, tested process for updating legacy systems.
- Incident Response: Ensure your OT teams are integrated into your broader cyber incident plans.
For guidance on assessing your OT security posture, see our OT Security DIAGNOSE Services.
Operational Technology is the operational backbone of modern industry — the systems that keep factories running, grids stable, and cities functioning. As these environments become more connected and data-driven, their exposure to cyber risk grows exponentially.
Understanding what OT is, how it differs from IT, and why it matters is the first step.
Securing it is the next.
