Five Easy OT Network Fixes that Improve Productivity and Security

When operations slow down or stop entirely, the root cause isn’t always a mechanical failure. In many industrial environments, OT network issues are to blame, causing unexpected device disconnects, lagging HMI screens, overloaded controllers, and hidden cybersecurity vulnerabilities.

Fortunately, small updates to your OT network can lead to big gains in productivity and security. This article explores five easy, low-cost improvements that can help keep your production running smoothly while enhancing your cybersecurity posture.

For more information on the value of an IT/OT network assessment or further help with IT/OT networking, don’t hesitate to reach out to E Tech Group.

Typical Symptoms
Devices unexpectedly disconnect, communication slows during peak production, or equipment stops responding without a clear cause.

What to Look For
Non-industrial switches such as Netgear or Linksys devices installed inside control panels.

Why it Happens
Unmanaged switches lack the ability to prioritize critical traffic, detect or isolate network issues, and do not support the industrial protocols required in OT environments. While they may function under light traffic conditions, they often fail under heavy load, leading to latency, dropped connections, and unreliable performance during peak production periods. This makes them unsuitable for environments where stability, determinism, and protocol compatibility are essential.

Consumer-grade switches are also prone to eventual failure from exposure to harsh industrial environmental conditions for which they are not designed.

Recommended Fix
Replace unmanaged or office-grade switches with industrial-grade managed switches designed for control environments.

Typical Symptoms
HMI screens lag or freeze, controllers slow down unexpectedly, or devices disconnect when the HMI is active.

What to Look For
HMIs with default communication settings that frequently scan large tag lists or request updates from PLCs at very short time intervals.

Why It Happens
Default HMI settings often request excessive data more frequently than the network can handle. This overload can stress PLCs and slow down production.

Recommended Fix
Adjust HMI settings to scan only essential tags, reduce polling frequency.

Typical Symptoms:

Slowed or interrupted data transmission between devices, along with intermittent network drops when nearby machinery starts or stops.

What to Look For:

Look for crimp-on RJ-45 plugs terminating unshielded Ethernet cables on the shop floor, Ethernet runs that share control panels or conduits with 480 V power wiring, and unmarked or sub-600 V-rated cabling that may not meet industrial requirements.

Why It Happens:
Crimped connectors are designed for static, office use. On the plant floor, continuous vibration, temperature swings, and cable flex quickly degrade the connection.

Unshielded, low voltage cables add two more risks:

Electromagnetic interference (EMI) – Variable frequency drives (VFDs), contactors, and other high-frequency devices generate electrical noise that can couple onto nearby data lines. This interference often leads to packet corruption, resulting in communication retries, data loss, or even data corruption—disrupting system reliability and performance
Fire and Signal Integrity Risks from Shared Wireways– Running Ethernet cables alongside 480 V circuits in the same enclosure or wireway can pose a fire hazard. If the cable insulation or shielding is not rated for at least 600 V, it may violate electrical code separation requirements and fail prematurely. Additionally, the high-frequency noise generated by 480 V circuits can interfere with Ethernet communication, leading to data errors and network instability when proper shielding is not in place.

Recommended Fix:

Re-terminate any crimp on plugs with industrial grade connectors that include proper strain relief.
Replace unshielded or < 600V rated cable with shielded, 600V rated industrial
Ethernet cable (STP or FTP) to block EMI and comply with code when installed alongside 480 V conductors.
Where possible, use pre-molded patch cords in panels and field terminable jacks in trays or conduits for maximum durability, protection, and long term reliability.

Typical Symptoms
Often none, until a security incident occurs.

What to Look For
Look for devices such as Ewon or Cradle point remote access units—cellular modems, VPN devices, or remote support boxes—often mounted by OEMs inside control panels and connected directly to the OT network.

Why it Happens
OEMs often install remote access devices to support their machines post-delivery, frequently leaving them with their default login credentials unchanged. Default credentials are often public information, posted in online forums or even the OEM’s manuals. These devices bypass any existing firewall or other network protection, making them a back-door onto the OT network and a serious cybersecurity risk. If unauthorized access to the device is gained—whether by OEM support personnel or other means—malware can be introduced into critical infrastructure with little to no detection, potentially compromising system integrity.

Recommended Fix
Disable or remove all OEM remote access boxes. These devices often operate outside the facility’s security monitoring and change control processes, creating significant blind spots in the OT environment. To reduce this risk, replace them with a plant-managed remote access platform that enforces secure authentication, session logging, and role-based permissions.

The replacement solution should include monitored, secure remote access capabilities such as multi-factor authentication, encrypted connections, session recording, and real-time alerts for connection activity. This ensures that all third-party and remote access is fully controlled and auditable.

Implementing a plant-owned solution also ensures alignment with cybersecurity best practices and supports ongoing compliance with cybersecurity insurance policies, industry standards, and regulatory frameworks. Most importantly, it protects critical infrastructure by eliminating unmanaged entry points into the OT network.

Typical Symptoms:
Frequent slowdowns in operations, unresponsive devices, or systems affected by malware.

What to Look For:
A flat (singular) network architecture where IT and OT devices are connected to the same network without separation.

Why It Happens:
Without segmentation between IT and OT, all traffic—business data, email, file sharing, control commands—flows together. Industrial equipment like robotics, PLCs, and CNC machines requires fast, deterministic communication that a traditional IT network cannot reliably support. This results in degraded performance and unstable operations.

Even more critically, this flat architecture exposes the OT network to the same cyber threats and malware that target IT systems, creating significant risk to production uptime and safety.

Recommended Fix:
Install a firewall to create a secure boundary between the IT and OT networks and implement network segmentation within the OT environment. Segmenting your network into logical zones—such as separating control systems from HMIs, or packaging lines from utilities—limits the spread of threats, enhances monitoring, and allows for more granular access control.

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Takeaways

Proper segmentation not only improves system reliability and visibility but is often a key requirement for cybersecurity insurance, regulatory compliance, and building a zero-trust architecture in industrial environments.

An IT/OT network assessment is a low-cost, high-impact way to uncover and address common issues while gaining a clear, comprehensive view of your OT infrastructure. It identifies outdated equipment, misconfigured devices, and cybersecurity blind spots and delivers a visual map of your network to improve understanding and visibility. The assessment also provides a prioritized asset inventory, helping you pinpoint which systems are most critical and most vulnerable. You’ll receive a phased upgrade plan aligned to your budget, production schedule, and long-term goals. Whether you’re preparing for digital transformation, tightening compliance, or simply working to eliminate persistent downtime issues, an IT/OT assessment gives you a strategic roadmap to modernize your operations with confidence.

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