# IPv4 subnet

How to check if an address belongs to subnet?

For example if your subnet mask is 255.255.255.0, the first 24bits / 3bytes will be the same if you are in same subnet.

e.g. if your ip is 192.0.2.1, you any other ip in the same subnet should be 192.0.2.X.

You could also denote this as 192.0.2.1/24, to indicate the first 24bits are reserved.

How to know if device is in same subnet?

10.0.0.0/8

172.16.0.0/12

192.168.0.0/16