Devices You Shouldn’t Connect to Your Wi-Fi Network

You shouldn’t connect IoT devices with weak security, such as cheap smart plugs, older IP cameras, and unknown-brand Wi-Fi thermostats, directly to your main home network because they can serve as an entry point for attackers to reach your computers and phones. Instead, put these devices on a separate guest or IoT network, or use a router that supports network segmentation. This article explains which devices pose the highest risk, why they are vulnerable, and how to isolate them without sacrificing convenience.

Why Some Devices Are Risky

Most people assume any Wi-Fi device is safe to connect, but the reality is that many smart home gadgets are built with minimal security. Manufacturers often prioritize low cost and quick time-to-market over firmware updates and encryption. A 2023 analysis by a security firm found that over 30% of common IoT devices had known vulnerabilities that were never patched. Unlike your laptop or phone, which receive regular OS updates, many smart plugs, cameras, and sensors stop getting updates after a year or two, leaving them permanently exposed.

Attackers scan the internet for vulnerable devices 24/7. If a device on your network has a default password or an unpatched flaw, it can be compromised in minutes. Once inside, the attacker can pivot to other devices on the same network, intercept traffic, or recruit the device into a botnet for DDoS attacks. The risk is not theoretical—the Mirai botnet in 2016 used default credentials on IP cameras to take down major websites, and similar attacks continue today.

Devices to Keep Off Your Main Network

Here are the most common categories of devices that you should not connect directly to your primary Wi-Fi network:

• Unknown-brand smart plugs and switches – Many are sold on marketplaces with no security testing, use unencrypted communication, and have no update mechanism.
• IP cameras and baby monitors – Especially older models or those with cloud accounts that have been breached. They often have open ports and weak authentication.
• Wi-Fi thermostats and sensors – Some budget models lack encryption and can be hijacked to read your schedule or even control your HVAC.
• Smart speakers and displays – While major brands are better, they still collect a lot of data and have had vulnerabilities. They should be on a separate network if you are privacy-conscious.
• Children’s toys with Wi-Fi – Many smart toys have been found to send data unencrypted and have poor parental controls.
• Printers and scanners – These often have open network ports and outdated firmware, making them a common target for attackers looking for a foothold.
• Any device you bought second-hand – You don’t know if it has been tampered with or if the previous owner still has cloud access.

This does not mean you cannot use these devices at all—it means you should isolate them from your main network where your personal data lives.

How to Create a Separate IoT Network

Most modern routers have a feature called “Guest Network” or “IoT Network.” This creates a separate Wi-Fi SSID that is isolated from your main network. Devices on the guest network can access the internet but cannot communicate with devices on your main network. Here’s how to set it up:

1. Log into your router’s admin page (usually via a web browser at an IP address like 192.168.1.1 or a mobile app).
2. Find the “Guest Network” or “IoT Network” settings. It may be under “Wireless” or “Network Settings.”
3. Enable the network and give it a different name (SSID) and a strong password.
4. If your router offers a “Device Isolation” or “AP Isolation” option, enable it to prevent devices on the guest network from talking to each other.
5. Connect your risky devices to this new network, not your main one.

If your router does not have a guest network option, you can buy a cheap second router and set it up as an access point with its own SSID, then connect that router to your main router via Ethernet. This physically separates the networks.

What to Do If You Must Connect a Risky Device

Sometimes you have no choice but to connect a smart device to your main network because it needs to communicate with other devices (e.g., a smart hub). In that case, take these precautions:

• Change the default password immediately and use a unique, strong password.
• Disable any features you don’t need, such as remote access, UPnP, or cloud services.
• Check for firmware updates and install them regularly. If the manufacturer no longer provides updates, consider replacing the device.
• Use a separate VLAN if your router supports it. VLANs are more secure than a guest network because they can be configured to allow only specific traffic.
• Monitor your network for unknown devices using your router’s device list or a network scanning app.

Common Misconceptions

One common misconception is that a strong Wi-Fi password is enough to protect your IoT devices. While a strong password prevents outsiders from joining your network, it does nothing to stop a compromised device from attacking other devices on the same network. Another myth is that only cheap devices are risky. Even major brands have had vulnerabilities, but they are more likely to release patches. The issue is that many IoT devices are “set and forget”—users never update them, so even patched vulnerabilities remain unpatched on their devices.

Another misconception is that a firewall on your computer protects you from IoT threats. A firewall only protects the device it is installed on, not the network. If an IoT device is compromised, it can send malicious traffic to your computer, and the firewall may not block it because it is coming from inside the network.

Comparing Security Options

There are several ways to secure your IoT devices, each with trade-offs:

• Guest Network – Easy to set up, works on most routers, but may not allow device-to-device communication, which some smart home setups require.
• VLAN – More secure and configurable, but requires a router that supports it and some networking knowledge.
• Separate Router – Simple and effective, but costs money and takes up space.
• Do Not Connect – The most secure option, but not practical for many smart home devices.

For most users, a guest network is the best balance of security and convenience. If you are tech-savvy, a VLAN is better.

Frequently Asked Questions

Can I connect my smart TV to the guest network?

Yes, but be aware that some smart TVs need to communicate with your phone or other devices for casting or control. If you put the TV on the guest network, those features may not work unless you also put your phone on the guest network. If you don’t use those features, it’s safer to put the TV on the guest network.

What about a smart doorbell or security camera?

These are high-risk because they are always on and often have cloud access. You should definitely put them on a separate network. If you need to view them from your phone, your phone can still access them over the internet, or you can allow a specific port on the VLAN.

Will a guest network slow down my internet?

No, a guest network uses the same internet connection, so there is no inherent speed loss. However, if you have many devices on the guest network, they may compete for bandwidth with your main devices. You can set bandwidth limits on some routers.

Is it safe to connect a smart speaker like Alexa or Google Home?

These devices are generally more secure than cheap IoT gadgets, but they still collect audio data and have had vulnerabilities. If you are concerned, put them on a guest network. You will still be able to use them for music and queries, but you may lose some cross-device automation.

How do I know if my router supports a guest network?

Check your router’s manual or log into the admin page and look for “Guest Network” or “IoT Network” in the wireless settings. Most routers from the last five years have this feature. If not, you can use a separate router.

What should I do with an old device that can’t be updated?

If a device no longer receives firmware updates, it is a security risk. The best option is to replace it. If you must keep it, put it on a guest network and disable any internet access if possible, or use a firewall rule to block its access to the internet except for essential services.

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