Subnet cheat sheet
| RFC1918 name | IP address range | Number of addresses | Classful Description | Largest CIDR block (subnet mask) | Host ID size |
| 24-bit block | 10.0.0.0 – 10.255.255.255 | 16,777,216 | single class A | 10.0.0.0/8 (255.0.0.0) | 24 bits |
| 20-bit block | 172.16.0.0 – 172.31.255.255 | 1,048,576 | 16 contiguous class Bs | 172.16.0.0/12 (255.240.0.0) | 20 bits |
| 16-bit block | 192.168.0.0 – 192.168.255.255 | 65,536 | 256 contiguous class Cs | 192.168.0.0/16 (255.255.0.0) | 16 bits |