Best practices for securing critical infrastructure IoT

Where things typically go wrong

Most teams discover the complications after deployment has started. Roaming can change how network address translation behaves, DNS resolution differs, and IP ranges aren’t what you expected. The private APN features you relied on in one country might work differently with another carrier. Setting up VPN hubs seems like the safe option, but then you’re forcing traffic on long detours and creating bottlenecks every time you need to make a change. Teams often respond by creating broad IP allowlists and trusting anything that appears to be “inside the tunnel”. Then audit season arrives, someone asks for evidence broken down by region, and you’re left manually stitching logs together.

The foundation: secure connectivity that travels

The solution starts with getting your connectivity layer right. When your devices can attach to multiple networks in each country and route traffic through private, isolated paths rather than the public internet, you’ve removed the most obvious attack surface. This means using private APNs or, where needed, IPsec VPN tunnels that keep your IoT traffic separated from general internet traffic, combined with direct connections to your cloud infrastructure where possible.

This approach gives you predictable data paths regardless of which carrier a device connects to in any given moment. Whether a device is operating in Norway, Germany, or further afield, it’s routing through the same secure infrastructure rather than unpredictable public internet hops. And where countries enforce permanent roaming limits, use eUICC with multi-IMSI or local profiles so devices remain compliant while keeping the same security posture.

Identity as the anchor point

Security across regions relies on devices having stable, verifiable identities. Each device should have a unique, non-exportable cryptographic key anchored in secure hardware—ideally in a secure element or embedded in the SIM itself. This identity shouldn’t change when a device moves between countries or switches carriers.

Think of your ICCID and IMEI as inventory markers rather than security credentials. The real trust comes from cryptographic proof that a device is what it claims to be, validated at every connection attempt.

Consistent security policies everywhere

The goal is straightforward: define your security rules once and have them apply consistently across all regions. Start with deny-by-default principles where devices can only communicate with explicitly approved services. Use mutual TLS to protect every service connection—telemetry, over-the-air updates, and administrative functions.

Most IoT deployments should operate outbound-only, with inbound connections closed entirely. This dramatically reduces your attack surface whilst still allowing devices to report data and receive updates. The beauty of this model is that it works the same way whether your device is connecting through a private APN in France, a VPN in Poland, or direct cloud integration in the UK.

Multi-network resilience

One of the biggest operational advantages in multi-region deployments comes from devices that can automatically switch between carriers. When a device powers up or moves location, it should seamlessly attach to the strongest available network without manual intervention. This isn’t just about coverage—it’s about maintaining connectivity even when a single carrier experiences issues.

This carrier-agnostic approach also protects you from permanent roaming restrictions that some countries enforce. Rather than managing complex roaming rules, your connectivity solution should handle network selection intelligently based on local requirements and availability—again, with eUICC and multi-IMSI or local profiles where appropriate.

Data residency without complexity

Meeting data residency requirements doesn’t mean forcing all traffic through one central hub. Instead, land your telemetry and update traffic in the nearest compliant region, using direct connections to your cloud infrastructure. Store and process data where regulations require, then replicate summaries to other regions as needed.

The key is separating the data handling requirements from your security model. Residency is about where data lives and how it’s processed. Security lives at the session and application layers, enforced consistently regardless of geography.

Avoiding backhaul traps

VPNs still have their place, particularly when legacy systems demand them. But modern IoT deployments shouldn’t rely on VPNs as their primary security mechanism. If you must use VPNs, terminate them locally in each region rather than creating long backhaul paths to a central concentrator.

Being “on the VPN” shouldn’t automatically grant access to anything beyond the specific services a device genuinely needs. For cloud-native architectures, prefer direct internet breakout from private APNs combined with strong authentication and encrypted connections to your services. This reduces latency and removes single points of failure.

Visibility and control at scale

Managing thousands of devices across regions requires real-time visibility into connectivity status, usage patterns, and network events. Your connectivity management platform should let you monitor the entire fleet from a single interface, with the ability to activate, suspend, or reconfigure devices regardless of their location.

API access becomes critical at scale, letting you automate lifecycle operations, set usage thresholds, and integrate connectivity management with your own provisioning systems. Every connection attempt, policy decision, and network event should generate logs that tie back to specific device identities and timestamps—essential for both troubleshooting and compliance reporting by region.

How IXT helps

IXT provides the connectivity foundation that makes multi-region security practical. Our global SIM works in over 190 countries with automatic multi-network access (multi-IMSI, SIM/eSIM/iSIM), so devices attach to the best local network without carrier lock-in or roaming headaches.

SecureNet delivers the private connectivity layer: dedicated APNs, IPsec tunnels where needed, and direct cloud connects to AWS, Azure and GCP—keeping IoT traffic off the public internet by default and avoiding backhaul bottlenecks. Built for Zero Trust, we combine strong device identity with least-privilege access and per-session policy controls.

Our Connectivity Management Platform gives real-time visibility and full API control, while the Global Data Pool simplifies operations and cost management. 

Multi-region security starts with getting your connectivity layer right. Use private, isolated paths rather than public internet by default. Ensure devices have stable identities that travel with them across borders. Define consistent security policies and enforce them everywhere. Give yourself visibility into what’s actually happening across your fleet.

Whether you’re deploying hundreds or hundreds of thousands of devices, the principles remain the same: predictable connectivity, verified identities, consistent policies, and comprehensive visibility. Get these foundations right, and scaling across regions becomes an operational task rather than a security crisis.

About the author

IXT writes about IoT connectivity because we build it. We’re a Full-MVNO with our own core network and a CMP we designed in-house, so we see what works at scale and what doesn’t. Our team has decades of experience in M2M/IoT, from network engineering to enterprise rollouts, so the guidance we share is practical, vendor-agnostic and field-tested. Connect, secure and manage devices with confidence using our IoT Connectivity.

IXT – Connected. Secure. Everywhere.