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.
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.
You do understand, when you have VM’s set to auto scale, they shutdown when not in use, if you’re using horizontal scaling.