I’m setting up DHCP reservations on my home network and came up with a simple schema to identify devices: .100 is for desktops, .200 for mobiles, .010 for my devices, .020 for my wife’s, and so on. Does anyone else use schemas like this? I’ve also got .local DNS names for each device, but having a consistent schema feels nice to be able to quickly identify devices by their IPs.
The term you are looking for is CIDR notation. The / is showing what the subnet mask is. So the subnet mask for a /8 is 255.0.0.0, which would be an extremely large network (over 16 million addresses, this was traditionally known as a Class A).
https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#CIDR_notation