I am worried that there is not really a benefit of doing that, just more noise and energy consumption.
Here’s my use-case, I’m pretty sure the first 2 are pretty common (common enough to be supported by most OEM firmware):
- main LAN
- guest LAN (isolated from “main” but can access internet)
- IoT LAN (isolated from internet, can be accessed from “main”; prevents devices from phoning home)
But you don’t need several LANs for this. This can easily done with proper routing. A can access internet and internal network addresses. B can only access internet, and C can only reach internal addresses.
I’m curious. How would you identify who’s guest and who’s not in this case?
With multiple networks it’s pretty easy as they are on a different network.
MAC whitelist.
That’s what MAC whitelists are for. Your DHCP server should be able to handle this.
Identify your friendly devices and give them one setting with everything (full subnet and correct default GW). Identfy your IoT devices, and give them another (full, or specially limited subnet mask, and fake default GW, maybe a different nameserver, too). Anything else is guest and gets a very limited subnet mask and a working default GW.
This is not the way to do it. The correct way would be multiple SSID’s with each tagged to their own VLAN.
Each VLAN has its own subnet. You can then use a zone based firewall, to allow the zones(subnets) to access each other.
You can also then apply QOS, to limit guest network speeds, prioritize LAN traffic etc.
And zone based firewalls are stateful, you can do rules such as LAN can reach IOT, but not the other way. Or IOT can only reach the IOT server, on specific ports.
I know that this would be the most secure way. But I seriously doubt that this level is necessary in a normal home network.
“Necessary” is a little ambiguous. You could argue that wifi is unnecessary for a normal home network.
Well, I think it is necessary if you have mobile devices. Anything nailed down should be connected by wire, but if it is mobile, it should get the connection. Especially if the cell phone link is not that good inside the house.
None of my mobile devices are “necessary,” though. Honestly, I could live just fine without an internet connection. Not that I’d enjoy it, but that’s not necessary.
My solution is the correct way and easier way. You don’t need MAC address white-list. You just have a guest SSID with DHCP on, they get the IP from the subnet in that zone. No crazy subnet hacks etc.
Can I join your guest network, sure. Let me just grab your mac address, login to the DHCP server, create a reservation with a limited subnet mask that can still see the default gateway.
Or can I connect to you guest network, sure here is the code or scan that QR code. That’s it, they’re in the guest VLAN and subnet, zoned off on the firewall and have QOS applied to not saturate the network.
For anyone reading this, please don’t follow this advice. It’s terrible and basically security through obscurity
