Look around, and you’ll see that everything from vehicles to medical sensors to industrial machines is now online. But with the prevalence of IoT devices comes an expanded attack surface. Protecting IoT networks requires robust, scalable security measures, and at the heart of this defense is network firewalls.
What Is a Network Firewall?
So, what are network firewalls? A network firewall is a security device or software designed to monitor, filter, and control incoming and outgoing network traffic. It acts as a barrier between trusted internal networks and untrusted external networks, such as the public internet. By applying a set of predefined security rules, network firewalls decide whether to allow or block specific traffic.
In the IoT world, where billions of devices are constantly exchanging data, a firewall is more than just a safety gate. It is a critical control point that ensures only legitimate traffic flows through while blocking malicious activity. Unlike traditional enterprise IT networks, IoT networks are often geographically dispersed, resource-constrained, and highly dynamic, making firewall functionality even more vital.
Why Network Firewalls Are Critical for Modern Security
Often less protected than laptops or servers, IoT devices are frequent targets of botnets and exploitation campaigns that co-opt vulnerable routers, cameras and industrial gateways. And once compromised, an IoT device can be used as an entry point into the wider network to launch DDoS attacks or as part of a botnet to launch large-scale campaigns. Recent advisories document Mirai‑based activity targeting industrial routers and smart‑home devices via zero‑day and known flaws, underscoring the need for strong, network‑level controls.
A properly deployed firewall network security posture helps IoT teams:
- Enforce allows‑lists and private networking (e.g., private APNs/VPNs) so devices only talk to required services.
- Detect and block threats near the edge, where devices connect.
- Monitor patterns to flag anomalies (e.g., a camera suddenly fanning out to many IPs).
Without a properly configured firewall, network security is a challenge, and IoT devices would be highly vulnerable to unauthorized access, data breaches, and service disruptions.
Core Functions of Network Firewalls
Access Control and Policy Enforcement
At its core, a firewall enforces policies that define which types of traffic are allowed or denied. For IoT deployments, this is critical. Devices often have very specific communication patterns. A smart meter might only need to communicate with a utility provider’s server, not the entire internet. Similarly, a connected medical device in a hospital may only be permitted to exchange data with an internal monitoring system or a secure cloud platform. Access control rules can ensure traffic stays within these parameters, significantly reducing the attack surface and preventing devices from becoming backdoors into the network.
Threat Detection and Prevention
Firewalls inspect traffic to detect threats such as malware, ransomware, or denial-of-service attempts. Advanced firewalls go beyond simple pattern matching and use behavioral analysis to detect zero-day threats. For IoT, this function is essential because many devices cannot run heavy endpoint protection software. The firewall becomes their primary defense mechanism.
Traffic Monitoring and Logging
As in any area of security, visibility is key. Firewalls continuously monitor and log network activity, providing administrators with actionable insights. Logs can reveal attempted intrusions, misconfigurations, or unusual device behavior. For IoT networks, this monitoring is particularly valuable because it helps identify compromised devices before they can be weaponized.
Take the example of a connected security camera in a smart city deployment. Under normal conditions, the device might stream video to a central management platform and receive periodic software updates. If the firewall logs show the camera suddenly trying to contact dozens of unfamiliar IP addresses across the globe, that anomaly is a red flag. It could indicate that the camera has been hijacked and is being used as part of a botnet to launch distributed denial-of-service (DDoS) attacks. With continuous monitoring and alerting in place, security teams can quickly isolate the device, investigate the root cause, and prevent wider damage.
Encryption and Decryption Handling
Many modern firewalls are capable of decrypting SSL/TLS traffic for inspection and then re-encrypting it before sending it on. This ensures that encrypted traffic cannot be used to hide malicious payloads. With IoT devices increasingly relying on secure protocols, firewalls with decryption capabilities are essential to maintain visibility into what is really happening inside the network.
For instance, a connected medical device may send encrypted patient data to a cloud platform. If attackers attempt to smuggle malicious code within that encrypted stream, a firewall with decryption capabilities can catch it before it ever reaches the hospital’s network.
How Network Firewalls Work
Firewalls analyze network packets as they move between sources and destinations. Depending on the firewall type, they may examine just the header information (like IP addresses and ports) or the entire payload. Based on predefined rules or real-time analysis, the firewall allows, blocks, or redirects the traffic.
For IoT, firewalls are often deployed at the edge of the network or even embedded into cloud-native solutions to protect devices across distributed environments. This makes them scalable and adaptable to the needs of globally deployed IoT devices.
Network Firewalls vs. Host-Based Firewalls
For IoT ecosystems, network firewalls are generally preferred to host-based firewalls because they provide scalable, centralized protection without burdening resource-constrained devices. Here’s a full breakdown.
| Feature | Network Firewall | Host-Based Firewall |
| Scope | Protects an entire network segment | Protects a single device |
| Deployment | Typically hardware appliance, virtual appliance, or cloud-native service | Installed directly on the device |
| Resource Requirements | Minimal impact on endpoints | Consumes CPU, memory, and storage of the host |
| IoT Feasibility | Well-suited for IoT environments, scalable across devices | Often impractical due to IoT devices’ limited resources |
| Use Case | Centralized protection for distributed networks | Added layer of defense for powerful endpoints like servers or PCs |
Types of Network Firewalls
When you’re asking yourself, what is a network firewall? Which should I opt for in my enterprise deployment, here are some examples you may come across:
- Packet Filtering Firewalls: The simplest form of firewall, packet filters check basic header information such as IP addresses and ports. They are lightweight but limited in functionality, as they cannot inspect the content of packets. For IoT, packet filtering may work for basic scenarios but does not provide sufficient protection against modern threats.
- Stateful Inspection Firewalls: Stateful firewalls keep track of active connections and can determine whether a packet is part of an existing session or a malicious attempt to initiate a new one. They provide stronger security than packet filters while remaining relatively efficient.
- Proxy Firewalls: These act as intermediaries between endpoints and external servers. They inspect traffic at the application layer, which allows for deep inspection and filtering. While effective, proxy firewalls can introduce latency, which may be a drawback for time-sensitive IoT applications.
- Next-Generation Firewalls (NGFW): NGFWs combine traditional firewall capabilities with advanced features like intrusion prevention, application awareness, and integrated threat intelligence. For IoT networks, NGFWs are highly effective because they provide granular visibility and can enforce policies tailored to device behavior.
- Unified Threat Management (UTM) Firewalls: UTMs bundle multiple security functions into a single platform, including firewalling, intrusion detection, antivirus, and VPN. This makes them appealing for organizations that want a consolidated security stack. For IoT, UTMs can simplify management but may lack the specialization required for large-scale, complex deployments.
- Firewall-as-a-Service (FWaaS) and Cloud-Native Firewalls: Finally, FWaaS delivers firewall capabilities as a cloud service, removing the need for on-premises hardware. Cloud-native firewalls are particularly well suited to IoT deployments, where devices are distributed across geographies. They provide centralized control, elastic scalability, and integration with cloud security ecosystems.
floLIVE’s Best Practices for Network Firewall Management
You may now know more about network firewalls than you ever thought possible! But most importantly, how do you deploy them with best practices in mind?
At floLIVE, we understand the unique security challenges of IoT. Our global connectivity solutions are designed with built-in security, ensuring that firewalls and other defenses are optimized for IoT-specific needs. By combining connectivity with security, enterprises can confidently deploy and scale their IoT networks without compromising safety. We believe in:
Regular Policy Reviews and Updates
Firewall rules should evolve alongside the network. IoT environments are dynamic, with new devices joining and leaving regularly. Regular reviews ensure that policies remain relevant and do not create unnecessary exposure.
Principle of Least Privilege
IoT devices should only be allowed to communicate with the endpoints they truly need. By applying the principle of least privilege, organizations minimize the risk of lateral movement within the network in the event of a breach.
Continuous Monitoring and Alerting
Firewalls should not only block traffic but also raise alerts for suspicious activity. With IoT networks operating at scale, automated monitoring and real-time alerts help teams respond quickly before small issues escalate into major incidents.
Implementing Redundancy and High Availability
Firewalls are critical components of the security architecture, and if they fail, the network can become exposed. High availability setups and redundant deployments ensure that firewall protections remain active even during outages or maintenance windows.
Testing and Auditing Firewall Configurations
Configuration errors are a common cause of firewall failures. Regular testing and audits help validate that rules are correctly applied and align with security policies. For IoT networks, where devices may behave unpredictably, ongoing audits are essential to catch misconfigurations early.
Network firewalls: Foundational to Securing IoT ecosystems.
From access control to threat prevention and deep traffic analysis, network firewalls provide the visibility and protection that connected devices need to operate safely. As IoT deployments continue to grow in size and complexity, organizations should embrace modern, cloud-native firewall solutions that can scale globally, enforce granular policies, and adapt to evolving threats.
Speak to us about how we ensure security as part of our global connectivity solution. Schedule a call.