Security issue with untrusted devices on your home network?
Security issue with untrusted devices on your home network?
Hello, I hope you're doing well. In my understanding, the clear answer to the question is generally 1. set up a separate VLAN; 2. keep them separated from each other and from the rest of your network; 3. restrict network access so only essential ports are open for trusted devices; 4. block untrusted devices from reaching the internet; 5. prevent them from connecting to general web domains; 6. allow them limited access to certain websites or addresses. Of course, in practice it's often not feasible. For instance, securing a Chromecast or similar device would require careful handling since it needs to reach many online services and updates. It’s unclear what exact subnets should be whitelisted, as information tends to change over time. Still, the main points remain relevant for most devices. a) It usually demands access to many unknown domains before any app is installed—like logging into Google or updating firmware. It seems unlikely that a complete list exists publicly. b) Most applications require internet access and rarely disclose the full range of needed domains. The more apps you use, the higher the chance something breaks even with initial firewall rules. c) Consumer devices typically don’t publish port details, making it hard to block them effectively. d) Installing services that interact with your network (like Spotify) often requires opening additional ports; though these tend to stay stable, setup remains complex. e) For features such as broadcasting or network discovery, cross-VLAN multicast is problematic and can cause major issues. f) Isolating the device only makes sense if it doesn’t need communication with other devices on your network. Otherwise, exceptions are necessary. In short, creating a dedicated VLAN and controlling access seems ideal, but real-world constraints make it challenging. What are the recommended approaches? Do you have any further questions? Thank you.
They can't reach your other devices that much? It really doesn't matter. My IoT gadgets stay confined to their own VLAN with no connection to anything else. For you, Number 6, I block unwanted ads, malicious software, crypto, and junk at the firewall across all networks (there are many updated lists for this). This would be simpler than just permitting only essential domains, since it would constantly change—especially with devices like a Chromecast—which would lead to frequent disruptions.
The problem lies in ensuring they can reach my other gadgets. For example, Chromecast needs to broadcast its status so Chrome displays a "Cast on..." option, allowing packets to reach the computer. A basic firewall rule should restrict any packet from Chromecast to only computers that recognize it. This stops a malicious program on Chromecast from attempting to infiltrate my NAS or home server, though my computer—often less secure—remains vulnerable. Configuring this is straightforward. The next layer involves controlling which traffic flows between Chromecast and computers. If broadcast packets are permitted but TCP to VNC is blocked, a trojan can’t guess passwords but could flood the network. Since Google hasn’t released specifics on this traffic, it must be determined through testing. For instance, if Spotify runs on Chromecast, it should only access the local network for remote control from nearby devices like smartphones.