Smart devices have become a normal part of many home networks. Televisions, streaming devices, speakers, cameras, doorbells, thermostats, lights, appliances, and game systems may all connect to the same router as personal computers and phones.
Although these devices are convenient, they do not always receive the same level of security support as a modern computer, which can create a security risk. One way to reduce the risk is to place smart devices on a separate guest or Internet of Things network.
This practice is called network segmentation.
What Is Network Segmentation?
Network segmentation means dividing one network into smaller groups. Instead of allowing every device to communicate freely with every other device, devices are separated according to their purpose and level of trust.
A simple home network might contain:
- A main network for trusted computers and phones.
- An IoT network for smart televisions, speakers, cameras, and appliances.
- A guest network for visitors’ devices.
Each group may still be able to access the internet, but access between the groups can be restricted, reducing the number of systems an attacker can reach if one of them is compromised.
Why Are Smart Devices a Concern?
Smart devices are not automatically dangerous, but they can introduce risks that are easy to overlook.
Limited Security Updates
Some manufacturers provide security updates for years, while others stop supporting products relatively quickly. A device may continue working long after it stops receiving security patches.
It may also be difficult to determine whether a smart television, camera, or appliance is running its latest software.
Weak or Unclear Security Controls
Some devices provide few security settings. They may use default services, unnecessary network features, weak authentication, or cloud accounts that are not protected with multifactor authentication.
Unlike a computer, a smart device may not support antivirus software, local monitoring tools, or detailed security logs.
Constant Internet Access
Many smart devices communicate regularly with cloud services. This may be necessary for remote control, notifications, updates, or voice-assistant features.
However, users may not have much visibility into what information is being sent, how often the device connects, or which external services it contacts.
Risk of Lateral Movement
Lateral movement occurs when an attacker compromises one device and then attempts to reach other devices on the same network.
For example, a vulnerable smart device connected to the main network might be able to communicate with computers, printers, shared storage, or other sensitive equipment.
Separating smart devices limits the number of valuable systems they can reach.
What Is an IoT Network?
IoT stands for Internet of Things. An IoT network is a separate network intended for smart and connected devices.
Some home routers provide a dedicated IoT network option. Others provide a guest network that can serve a similar purpose. Advanced networks may use virtual local area networks, commonly called VLANs.
For many households, a properly isolated guest or IoT network is the simplest place to begin.
The important word is “isolated.” Creating a second Wi-Fi name does not guarantee that the devices are separated. The router must also restrict communication between the IoT network and the trusted main network.
Look for settings with names such as:
- Block access to the local network.
- Isolate guest devices.
- Allow internet access only.
- Prevent access to the LAN.
- Client isolation.
- AP isolation.
The exact names and behavior vary between routers.
Segmentation Versus Device Isolation
Segmentation and device isolation are related, but they are not identical.
Segmentation separates groups of devices. A smart device on the IoT network may be prevented from reaching a computer on the main network.
Device or client isolation prevents devices within the same network from communicating directly with one another. For example, two devices connected to the guest network may both have internet access but may not be able to communicate with each other.
Client isolation can provide additional protection, but it may also interfere with legitimate functions. Smart-home hubs, wireless speakers, printers, casting devices, and local controllers may need to communicate with other devices.
For this reason, isolation should be enabled carefully and tested rather than assumed to work with every smart-home product.
Which Devices Belong on the IoT Network?
Possible candidates include:
- Smart televisions.
- Streaming devices.
- Smart speakers.
- Cameras and video doorbells.
- Smart lights and switches.
- Thermostats.
- Connected appliances.
- Robot vacuums.
- Smart-home hubs.
- Game consoles.
- Other devices that primarily require internet access.
Trusted computers and phones normally remain on the main network. These devices may contain personal documents, saved sessions, financial information, browser data, and other sensitive material.
A phone used to manage smart devices can often remain on the main network, but this depends on the router and the way the smart devices are controlled.
Plan Before Changing the Network
Before creating a new network, make a private inventory of the existing devices. Record the device type, owner, connection method, and expected purpose.
Also determine how each smart device is controlled:
- Does it communicate entirely through a cloud service?
- Does a phone need to discover it locally?
- Does it require a smart-home hub?
- Does it depend on casting or screen sharing?
- Does it need to communicate with a printer or storage device?
- Does it only support 2.4 GHz Wi-Fi?
- Is it connected through Ethernet instead of Wi-Fi?
This information helps predict which features might stop working after segmentation.
It is also wise to save a router configuration backup, record the current settings privately, and make changes while physically connected to the home network. Avoid experimenting when remote access is the only way to reach the router.
A General Setup Process
Router interfaces differ, but the basic process is usually similar.
1. Create a Separate Network
Open the router’s administration panel and look for Guest Network, IoT Network, or a similar option.
Create a separate Wi-Fi name that does not reveal the owner’s name, address, router model, or other personal information.
2. Use a Unique Password
Protect the new network with a strong password that is different from the main Wi-Fi password.
Use WPA2 or WPA3 security when supported. Some older smart devices may not support newer WPA3-only configurations, so compatibility should be tested.
3. Restrict Access to the Main Network
Disable the IoT or guest network’s access to the main local network when the router provides this option.
The goal is to allow smart devices to reach the internet without giving them unrestricted access to trusted computers and other private systems.
4. Move One Device at a Time
Do not move every smart device at once. Start with one noncritical device, connect it to the new network, and test it.
Confirm that it can:
- Connect to the internet.
- Receive updates.
- Communicate with its official application.
- Perform its normal functions.
- Recover properly after a restart.
Moving devices individually makes troubleshooting much easier.
5. Test Local Features
Check any features that depend on local communication, including casting, printing, media sharing, smart-home hubs, speakers, and local device discovery.
If a feature stops working, determine whether the router supports a controlled method of allowing the required traffic between networks. Avoid disabling all isolation simply to solve one compatibility problem.
6. Document the Result
Update the private device inventory after each device is moved. Record the network group, test results, problems encountered, and any exceptions that were required.
Do not publish real Wi-Fi names, passwords, IP addresses, MAC addresses, device names, or screenshots containing private network details.
What Segmentation Cannot Do
Network segmentation is an important protective control, but it is not a complete security solution.
It does not replace:
- Router and device updates.
- Strong, unique account passwords.
- Multifactor authentication.
- Secure router administration.
- Removal of unused devices.
- Review of cloud-account permissions.
- Backups of important information.
- Monitoring for unexpected network activity.
Segmentation also cannot prevent every compromised device from communicating with a malicious service on the internet. Its primary purpose is to limit what that device can reach inside the home network.
Maintaining the IoT Network
Review the IoT network regularly.
A useful schedule is:
- Monthly: Check for unfamiliar connected devices.
- Quarterly: Review the complete inventory and verify that expected devices are still present.
- After purchasing a device: Decide which network it should use before connecting it.
- After unusual activity: Review connected clients, update passwords if necessary, and investigate unexpected changes.
- When retiring a device: Remove it from the inventory and delete its associated account or cloud access when possible.
Final Thoughts
Separating smart devices from trusted computers is a practical example of defense in depth. If one smart device becomes vulnerable, segmentation can reduce its ability to reach more valuable systems.
The safest approach is to begin with a private inventory, understand how the devices communicate, create an isolated network, and move devices one at a time. Careful testing is essential because some smart-home features rely on local communication.
A separate IoT network does not eliminate every risk, but it creates an important boundary between less-trusted equipment and the devices that contain the household’s most sensitive information.