An SI’s Fast Pass to OT Network Resilience: Overcoming 3 Major Brownfield Challenges

Building resilient OT networks is more complex than ever. Consequently, system Integrators (SIs) are caught in a tight spot, forced to reconcile rigorous cybersecurity regulations like IEC 62443 with non-negotiable demands for zero downtime. SIs widely agree that implementing advanced security measures in delicate brownfield settings often triggers integration nightmares and production disruptions.

So, how can they speed up system integration projects without falling into hidden traps? You’ll find everything you need in this navigation guide for secure, reliable, and compliant networks.

Hidden Trap 1: The Massive Effort of System-wide IEC 62443 Compliance

Are you feeling the heat from customers demanding strict adherence to IEC 62443 standards? IEC 62443 is a broad set of cybersecurity requirements, encompassing industrial automation control systems’ components, systems, and their integration.

A common pitfall for SIs is the massive effort required to bridge the gap between device-level capabilities and system-level execution. Purchasing IEC 62443-4-2 compliant, security-hardened devices is a great start, but system integrators and asset owners still need to address the complex, system-wide requirements of IEC 62443-3-3. Significant time and effort are needed to redesign vulnerable networks to meet these rigid standards.

Our Navigation Guide: Accelerate Your Path to Compliance

System-level compliance doesn’t necessarily mean using individually certified products. Opting for devices created within a stringent security framework provides SIs with a more extensive and dependable array of options. We implement a Secure Development Life-cycle (SDL) process certified to IEC 62443-4-1 ML3, which is why we guarantee a secure-by-design foundation throughout our networking portfolio.

For projects that strictly require certified hardware, we provide a complete portfolio of IEC 62443-4-2 Security Level 2 certified devices, anchored by the EDS-4000/G4000 Series secure managed switches and the EDR-G9010 Series industrial firewalls. By partnering with a vendor that offers both a secure development philosophy and a comprehensive lineup of certified products, SIs can significantly accelerate their journey toward building a compliant, defense-in-depth architecture.

As an IEC 62443-4-1 ML3 certified company and an IEC 62443-4-2 certified networking solution provider, we commit ourselves to helping you build resilient network security and advance your efforts to achieve IEC 62443-3-3 system-wide compliance. Download our white paper to learn how we can help you implement IEC 62443-3-3 from a networking perspective.

Hidden Trap 2: The “Rip-and-replace” Nightmare in Brownfield Segmentation

For SIs in brownfield environments, a major hurdle is that segmentation updates frequently require altering PLC IP addresses—a risky move that can halt production. Furthermore, if an inline security device fails, it can cause a “fail-close” scenario, shutting down critical control loops and incurring massive financial losses by the minute.

Additionally, consider the growing need to send substantial data volumes throughout the factory. Managing multiple projects simultaneously is tough enough. Sourcing and testing solutions for clients with vastly different security and uptime requirements makes it an even more daunting, time-consuming task for SIs.

Our Navigation Guide: Your One-stop Shop for Brownfield Revamps

To meet diverse security and performance demands, we offer a comprehensive portfolio of managed switches and industrial firewalls to help you build resilient networks for your customers. Instead of piecing together solutions from multiple vendors, you can rely on Moxa’s toolkit for brownfield scenarios:

Step 1: Establish Basic Segmentation

For immediate brownfield security improvements, upgrade your unmanaged switches to our secure managed switches. You get network status and can use VLANs or subnetting for straightforward, effective segmentation.

Step 2: Protect Legacy Systems Transparently

Our EDF-G1002-BP firewalls can function as a Layer 2 Transparent Bridge, which is ideal for safeguarding legacy systems that cannot be patched, such as Windows XP HMIs. Position the firewall inconspicuously in front of legacy machines to maintain existing IP addresses and routing configurations.

In OT environments prioritizing continuity, we recommend a step-by-step approach. Begin with Intrusion Detection System (IDS) mode — passively monitoring and logging traffic without any blocking action — to build visibility into normal OT communication patterns. Doing so directly addresses a critical OT concern: “What if the firewall blocks something it shouldn’t and takes down the line?” The IDS-first approach gives you the data and confidence needed to answer that question before any active enforcement begins.

After setting up a dependable traffic baseline, you can gradually activate Intrusion Prevention System (IPS) and Deep Packet Inspection (DPI) rules for recognized threat signatures. Time-sensitive control traffic can be exempt from IPS inspection, thus maintaining the determinism of OT control loops and ensuring operational performance is not compromised by security.

Want to know the technical differences between routed and transparent firewalls? You can learn about how to choose suitable industrial firewalls for your projects in our white paper.

Step 3: Scale Up Segmentation and Remote Access

For extensive network segmentation, our EDR-8010 Series firewalls build multiple complex segments, support 1:1 NAT for identical OEM skids, and offer secure VPN tunnels for remote access.

Step 4: Ensure Uncompromising Reliability

We understand the OT mandate of “uptime over everything.” That’s why we build our security solution to avoid a single point of failure. Advanced industrial firewalls, such as the EDF-G1002-BP and EDR-G9004 Series, feature Gen3 LAN Bypass technology. If the firewall loses power or experiences a system crash, mechanical relays instantly engage a fail-to-wire bypass, keeping critical PLC-to-I/O communications uninterrupted. Meanwhile, our secure managed switches and EDR-8010/G9010 Series firewalls provide robust fail-safe redundancy mechanisms to keep large-scale networks running smoothly, even under heavy data loads.

Hidden Trap 3: The Burden of Complex Deployment and Pay-to-play Maintenance

Many firewall solutions on the market come with overly complex management interfaces and aggressive pay-to-play subscription models. For SIs, this creates a massive bottleneck during commissioning, turning the deployment of network settings and firewall rules across dozens of devices into a labor-intensive nightmare.

It’s only after the project handover that the trap truly closes. Customers get tired of complex setups for daily maintenance, making routine fixes almost impossible without expert network skills. Worse, mandatory recurring subscriptions act as a ticking time bomb: If a customer forgets to renew a license, some solutions on the market will lock users out or stop forwarding traffic entirely. Such action leads to catastrophic, self-inflicted system downtime, tarnishing the SI’s reputation.

Our Navigation Guide: Streamlined Operations and Predictable TCO

Our solutions empower SIs to achieve quicker deployments, simpler troubleshooting, and confident project handovers. By stripping away complexity, we ensure your jobs are highly profitable to install and effortless for your clients to maintain.

Comprehensive Network and Security Visibility

Moxa provides a powerful dual-software approach designed specifically for industrial personnel, replacing complex command lines with intuitive visual management:

• MXview One: Automatically maps out the entire physical network topology, giving SIs and operators real-time visibility into device health, link status, and network redundancy. It helps SIs pinpoint physical connection issues instantly during deployment.

• MXsecurity: Acts as the centralized brain, allowing SIs to easily orchestrate firewall policies, NAT rules, and threat monitoring across dozens of remote devices through a centralized, visual interface. This ensures consistent policy deployment across mass nodes in just a few clicks, significantly reducing the risk of human error during large-scale provisioning.

CapEx-friendly Licensing With Out-of-the-box Protection

Moxa champions an OT-friendly purchasing model. Core functionalities—including routing, NAT, and firewall filtering—are built into the hardware with no recurring subscription required.

Advanced industrial firewalls such as the EDF-G1002-BP include factory-installed IPS licenses, with point-based subscriptions for additional IPS pattern updates to safeguard against emerging threats.

When you accidentally miss the renewal of the IPS pattern update subscription, the IPS functions will continue to work, but will not receive IPS pattern updates. This scenario won’t stop your network from forwarding traffic simply because a subscription lapses. This gives you a clear, predictable TCO to present to customers. No subscription-induced downtime, no feature deactivation surprises—just a solution that keeps working.

Are you ready to enhance network security and reliability without integration headaches? Achieving true OT network resilience requires more than a single device. Moxa’s secure networking portfolio—featuring managed switches, industrial firewalls, and centralized management software—is your fast pass to bypassing brownfield traps.

Explore our full range of secure networking solutions and find the right fit for your next integration project now.