255.255.255.0 /24
1 subnet, 254 possible hosts
255.255.255.128 /25
2 subnets, 126 possible hosts
255.255.255.192 /26
4 subnets, 62 hosts
255.255.255.224 /27
8 subnets, 30 hosts
255.255.255.240 /28
16 subnets, 14 hosts
255.255.255.248 /29
32 subnets, 6 hosts
255.255.255.252 /30
64 subnets, 2 hosts
255.255.255.254 /31
128 subnets ... no hosts?
255.255.255.255 /32
256 subnets again no hosts?