IoT connectivity: a practical reference for engineers and integrators
How cellular networks, SIM cards, VPNs, industrial routers, and edge architecture actually work in real-world UK deployments – not in marketing diagrams. Written for engineers, integrators, and technical decision-makers who need clarity rather than hype.
Start here: key guides
Remote access, VPNs and port forwarding
How engineers connect to devices at remote sites over cellular networks – and why the answer has changed significantly in the last few years. Port forwarding, private APNs, overlay VPNs, and VPS hubs each solve different parts of the problem.
- Port forwarding on industrial routers: public IP, private APN, overlay VPN and VPS explained New
- VPS for SCADA, CCTV and industrial remote access: a practical guide New
- Private vs public IP for cellular IoT: CGNAT, private APNs and static IPs explained Deep dive
- Remote access to SCADA systems: platforms and connectivity options Guide
Key concept: most 4G and 5G SIM cards sit behind carrier-grade NAT (CGNAT). Port forwarding does not work behind CGNAT. If you are searching “port forwarding not working on EE” or “can’t access router remotely on 4G” – this is the likely cause. The guides above explain the alternatives clearly.
SCADA, industrial automation and utilities
Cellular connectivity for industrial control systems, SCADA, water treatment, energy, and critical infrastructure. Covers router selection, protocol compatibility, remote access architectures, and security requirements.
- SCADA over cellular: 4G, 5G and industrial connectivity Guide
- Remote access to SCADA systems: platforms and connectivity Guide
- VPS for SCADA, CCTV and industrial remote access New
SIM cards, IP addressing and cellular networks
How IoT SIM cards differ from consumer SIMs, what private APNs actually do, how CGNAT affects remote access, and how IP addressing works across cellular networks.
- Private vs public IP for cellular IoT Deep dive
- IoT SIM cards explained Reference
- IoT SIM card directory Directory
- eSIM and iSIM articles Category
- UK network coverage and news Category
Industrial routers and gateways
Hardware selection, specifications, and real-world deployment guidance for cellular routers and IoT gateways. Covers Teltonika, Milesight, Robustel, and other industrial brands.
- Cellular router classifications explained Reference
- Routers and gateways hardware database Directory
- Low-power industrial cellular routers for off-grid IoT Guide
- 4G connectivity for deployable CCTV towers Guide
- Teltonika router articles Category
- Milesight router articles Category
- Robustel articles Category
Edge computing and IoT architecture
How data moves from sensors and devices to the cloud, and where processing increasingly happens at the edge. Covers gateway architectures, Docker on industrial routers, and the trade-offs between edge and cloud processing.
Security, compliance and connectivity design
IoT security is an architectural question before it is a product question. This section covers VPN-first design, reducing attack surface, regulatory requirements, and why the default assumption of “public IP SIM” is increasingly the wrong starting point.
- Port forwarding vs VPN vs private APN: security implications explained New
- Why public IP SIMs expose industrial equipment to Shodan and automated scanners New
- IoT security articles Category
LPWAN, LoRaWAN and low-power sensor networks
Where cellular is too expensive or power-hungry, LPWAN technologies like LoRaWAN provide long-range, low-power connectivity for sensors. This section covers the architectures, trade-offs, and backhaul designs used in real deployments.
- Low-power IoT routers: solar and battery deployments Guide
- Connectivity articles including LPWAN and LoRaWAN Category
What this library covers: topics at a glance
- Private vs public IP
- CGNAT explained
- LTE Cat 1, Cat 4, Cat 6
- 5G for IoT
- UK network coverage
- IoT SIM explained
- SIM card directory
- Private APN
- Roaming SIMs
- eSIM and eUICC
- Port forwarding explained
- VPS for SCADA and CCTV
- WireGuard on industrial routers
- OpenVPN vs WireGuard
- Zero-trust IoT access
- SCADA over cellular
- SCADA remote access
- Modbus TCP over VPN
- DNP3 and IEC 60870
- Water and utilities
- Edge computing
- Docker on routers
- MQTT and cloud platforms
- Data to server patterns
- On-device processing
About this section
This connectivity library is written by Peter Green, an industrial IoT and M2M connectivity specialist with over 25 years of experience in cellular, SCADA, and IoT network design. Articles are written for engineers and integrators who need practical guidance rather than vendor marketing.
Content is updated as technologies and deployment patterns evolve. Where articles describe concepts that are changing rapidly – 5G RedCap, eSIM, private 5G – they are reviewed and revised as the market develops.
If you design, deploy, specify, or support IoT connectivity systems and have a question not covered here, use the contact page or submit an article.