Source: https://cleantalk.org/help/sfw-blocks-networks
| 1.2.3.4 | A regular IP address |
| 0.0.0.0/0 | All possible IP addresses (only with 0.0.0.0 so you don’t want that) |
| 1.2.3.4/8 | All IP addresses starting from 1.n.n.n (from 1.0.0.0 to 1.255.255.255). |
| 1.2.3.4/16 | All IP addresses starting from 1.2.n.n (from 1.2.0.0 to 1.2.255.255). |
| 1.2.3.4/24 | All IP addresses starting from 1.2.3.n (from 1.2.3.0 to 1.2.3.255). |