Understanding the Network Choices That Shape IoT Reliability, Safety, and Performance

As IoT deployments scale across industries — from connected medical devices to smart meters and autonomous vehicles — the security of device communications becomes one of the most important infrastructure decisions an organization must make. At the heart of this decision lies a key question:
Should your IoT devices communicate over the public internet using standard mobile data, or should you deploy a Private APN for controlled, secure connectivity?

Both environments have strengths, but the differences matter — especially when dealing with mission-critical or sensitive data. Understanding how each option works, and the risks and benefits associated with them, will help you choose the right foundation for your IoT ecosystem.

🌐 What Is Public Internet Access for IoT Devices?

When IoT devices use a standard mobile data connection, they operate just like any smartphone or tablet: they connect to the public internet through a mobile network operator’s (MNO’s) infrastructure.

Advantages of Public Internet Access:

Easy to deploy — no special setup required
Cost-effective for small or non-critical deployments
Globally compatible with minimal technical configuration
Fast to scale for testing or early-stage rollouts

However, because traffic flows through the public internet, devices become more vulnerable to several risks, including:

Exposure to public IP ranges, which makes them discoverable
Higher risk of malware, spoofing, SIM hijacking, and DDoS attacks
Greater dependency on the MNO’s shared network environment, offering less control
Difficulty enforcing strict firewall or routing policies across fleets

For many consumer IoT deployments this setup can still be appropriate, but for enterprise IoT — especially in industries like healthcare, energy, transportation, and government — public connectivity often introduces unacceptable security gaps.

🛡️ What Is a Private APN?

A Private Access Point Name (Private APN) gives enterprises their own dedicated gateway into a mobile network. Instead of devices connecting to the open internet, they connect to a private, isolated network environment that only your organization controls.

Think of it as a secure tunnel carved inside the mobile network operator’s infrastructure.

How It Works:

Devices connect using a private APN identifier
All data routes through segregated gateways, not the public internet
Traffic can be directed into your corporate network, cloud environment, or VPN
Devices typically receive private (non-routable) IPs
Firewalls, routing rules, and access policies become fully customizable

A Private APN is essentially your private network in the cloud, with mobile connectivity as its backbone.

🔒 Security Benefits of Private APN for IoT

When protecting IoT devices from external threats, a Private APN offers multiple layers of hardened security. For mission-critical applications, this can be the difference between stable uptime and catastrophic vulnerability.

1. Devices Become Invisible to the Public Internet

Most cyberattacks begin with network scanning and enumeration.
With a Private APN:

Devices cannot be scanned
They cannot be directly reached from outside networks
Attackers have no entry point to probe

This reduces the threat surface dramatically.

2. Controlled, Encrypted Tunnels (VPN / IPsec / GRE)

Private APNs typically integrate with:

IPsec tunnels
Private VPNs
Cloud interconnects (AWS, Azure, GCP)

This ensures that data travels through secure, encrypted channels from device to backend — never in the open.

3. Custom Firewall, ACL, and Routing Policies

Instead of relying on a mobile carrier’s general-purpose security, you can define:

Whitelisted IP ranges
Layer-3 and Layer-7 firewall rules
Device-to-device communication policies
Traffic shaping, filtering, and monitoring rules

This level of control is impossible with public internet access.

4. Private Static IPs for Secure Device Management

Private APNs allow each IoT device to receive a private, fixed IP address, enabling:

Device authentication
Secure remote management
Predictable asset routing
Cloud-based command and control

In contrast, public connectivity typically assigns dynamic, carrier-NATed IPs with limited remote-access options and higher security risks.

5. Better Protection Against SIM-Based Attacks

With a Private APN environment, you can enforce:

IMEI-locking
SIM-to-device binding
Closed-loop routing
Access limiters (aka IP Filtering)

These policies greatly reduce risks like SIM cloning, SIM swapping, or unauthorized usage.

🏢 Why Enterprises Prefer Private APNs for IoT at Scale

As IoT fleets grow into the thousands or millions of devices, enterprises need to guarantee not only security but also operational control and network predictability.

Private APNs provide:

Centralized oversight and uniform policy enforcement

Security and network rules apply instantly across all devices — no matter where they are located globally.

Higher uptime and stability

Private routes avoid public internet congestion and lower latency variability.

Improved compliance posture

For industries regulated by HIPAA, GDPR, SOC2, or NERC-CIP, private traffic flows simplify compliance by keeping data segmented and auditable.

Seamless integration with corporate IT infrastructure

A Private APN acts like an extension of your internal network — making IoT part of your enterprise architecture rather than an isolated environment.

⚖️ Private APN vs. Public Internet for IoT: Quick Comparison

Feature	Public Internet Access	Private APN
Security Level	Moderate (shared network)	High (isolated and private)
Device Exposure	Public-facing IPs	Not exposed to internet
Management	Limited control	Full policy, routing & firewall control
Scalability	Good for small fleets	Best for medium-to-large fleets
Compliance	Harder to meet strict standards	Easier to secure & audit
Cost	Lower	Higher but justified for enterprise-grade security

🧭 When Should You Choose a Private APN?

A Private APN is ideal when:

Devices transmit sensitive data (healthcare, government, finance)
Uptime is mission-critical (utilities, EV charging, industrial automation)
Devices run in remote or hostile environments
You manage hundreds or thousands of IoT endpoints
Direct device access or remote management is required
Compliance and audit trails matter

If security, reliability, and centralized control are top priorities, a Private APN will always outperform public internet access.

🚀 The OneSimCard IoT Advantage

OneSimCard IoT provides robust connectivity solutions tailored for enterprise IoT security, including:

Private APN options with custom IP ranges
Private static IPs and secure VPN tunnels
Multi-IMSI global IoT SIM cards for maximum uptime
Non-steered connectivity to ensure the strongest network at all times
International coverage across 200+ countries
Advanced SIM management portal for real-time monitoring and control

With OneSimCard IoT, your devices operate inside a secure, isolated, enterprise-grade environment — ensuring your IoT data stays protected from the first packet to the last.

🔚 Final Thoughts

As IoT continues to shape industries around the world, the network environment you choose will directly impact your security, reliability, and operational costs. Public internet access can work for small-scale or low-risk deployments, but when your IoT infrastructure becomes mission-critical, the benefits of a Private APN become undeniable.

Private APN = security, visibility, and control.
Public Internet = convenience and quick deployment.

For enterprises serious about IoT security, the choice is clear.

Security is on top of mind for every stakeholder of IoT device deployments and discussions of the best way to secure data is ongoing and constantly evolving. We are regularly consulted on how to harden IoT device data specifically related to IoT SIM cards and data transfer. The goal of this article is to share best practices we have learned over the many years we have been dealing with this question particularly related to the risk of Public Static IP’s and how to mitigate this risk.

Most devices that are deployed with IoT SIM cards deliver data unidirectionally by sending data from the device to your server based on time interval or event triggers and no reply/response is required from the server back to the device, or bidirectionally sending data to and receiving data from the IoT device. This bidirectional communication is where we will concentrate.

Bidirectional data transfer without using Static IPs is typically accomplished using 2 distinct methods:

Polling – this is accomplished by the IoT device initiating communication with your server using protocols like HTTP to request information from the server. Your server can then capture the IP address of the IoT SIM and send its response back to the device using this now known dynamic IP address. This works well for cases when the IoT device is able to initiate communication, or “poll,” typically based on time intervals or if a certain event triggers this communication.
Socket based – where the device maintains an open connection with your server using protocols such as MQTT. The persistent, open connection allows both the IoT device and your server to communicate with each other independently from one another. Unlike polling, neither the device nor the server relies on the other to initiate communication.

While these examples of bidirectional communication are viable, they do have significant drawbacks:

Polling relies on the IoT device to initiate communication with the server and this, as previously mentioned, is based on time or event triggers which don’t allow for you to connect with the IoT device whenever you want; you have to wait for the device to initiate and this could be too long of a period of time.
Socket based communication relies on the persistent connection which for a number of reasons could get interrupted. If the connection is interrupted, then you must wait for the device to open another connection because the dynamic IP address of the IoT SIM card could have changed and there is no way of knowing the new IP address for the IoT SIM card.
Not all devices support these types of communication protocols and this limits your choices when choosing IoT devices for your project.

Because of these considerable drawbacks, enterprises use Static IPs on IoT SIM cards for much more reliable bidirectional communication. Static IPs allow you to communicate with the IoT device at any time because, by definition, you always know the IP address of the SIM card. There are two types of Static IPs, Public and Private. We are going to talk about replacing Public Static IPs with Private Static IPs because of the security and cost concerns with Public Static IPs.

First, it is important to understand a bit more about Public Static IPs.

Public Static IPs

IoT SIM cards with Public Static IPs have been used for IoT deployments for bidirectional communication between IoT devices and servers for many years. These static IPs allow you to proactively reach out to a remote IoT device in the field at any time using the known IP address. Because these are Public IP addresses, you can communicate with your devices from any machine which, on first blush, seems like a handy solution. This access raises an enormous security concern though. By definition, these IPs are addressable to any machine on the public internet, which forces organizations to implement ancillary security methods like rotating passwords, whitelisting incoming connections and turning off services which aren’t being used. This security concern also extends to the server to which the IoT device connects, because that server also needs to be publicly available. Here is a diagram of this design:

As you can see, this design is inherently flawed from a security standpoint because the use of publicly accessible IPs exposes your deployment to intrusion by hackers from anywhere in the world.

Security isn’t the only concern when using IoT SIM cards with Public IPs, though. Cost is another consideration. Just like Real Estate, there is a finite number of Public IPs available. This drives the cost of Public Static IPs higher and it takes time to deploy these Public IPs from the network carriers. Cost and time are major hindrances to effective IoT device deployment.

IoT SIM cards with Private Static IPs – The Solution to Replace Public Static IPs

The other method to bidirectional communication is to deploy Private Static IPs on your IoT SIM cards. Just like Public Static IPs, Private Static IPs allow you to always know the address of your device and access the device at any time. However, IoT Sim cards with Private Static IPs do not allow public access to the IoT device because only devices or servers on the private network are allowed to communicate with the devices within the network. It is possible, if necessary, to send data from the IoT device to a place on the public internet (external site) but proactive communication to the IoT SIM card can only be initiated from within the private network. We create this private network in 2 ways.

Peer to Peer communication. This method uses an IoT SIM card with Private Static IP in your IoT device and another IoT SIM card either in a router behind your firewall, or in another IoT device if the devices need to communicate with each other. Peer to Peer communication is typically used when small amounts of data is being used because you are essentially doubling your cellular data consumption because the IoT SIM card on your server is acting as the data connection rather than traditional ISPs. This can be expensive if large amounts of data are being transferred, and;
VPN connection. VPN (IPsec or OpenVPN) is a much more common method to create the connection to the IoT SIM card with Private Static IP. The way this works is a VPN connection is made from your server to our server which, by rule, is connected to all of our IoT SIM cards. This tunnel communicates securely to your IoT devices because the traffic is encrypted end to end and all traffic is kept within this secure tunnel. This is by far the most secure and cost-effective way to maintain bidirectional communication with your IoT devices.

Below are diagrams demonstrating Peer to Peer and VPN connections with Private Static IPs:

Peer to Peer Connection:

Peer to Peer Connection

VPN Connection with Private Static IPs:

VPN Connection with Private Static IPs

Clearly, using Private Static IPs on IoT SIM cards is a much more elegant and secure way to communicate. This setup will allow reliable, cost-effective bidirectional communication between your servers and your IoT devices and it reduces the need for further hardening which is required when using Public Static IPs.

If you would like to speak with one of our IoT experts, please reach out to us anytime at sales@onesimcard.com.

Tag: IoT security

Private APN vs. Public Internet Access: What’s Best for IoT Security?