| CIDR Notation | Number of IP Addresses That Will Be Blocked/Permitted (depending on usage) | Netmask (for information/amusement only) |
|---|---|---|
| /24 | 256 (Entire class C) | 255.255.255.0 | /25 | 128 | 255.255.255.128 | /26 | 64 | 255.255.255.192 | /27 | 32 | 255.255.255.224 | /28 | 16 | 255.255.255.240 | /29 | 8 | 255.255.255.248 | /30 | 4 | 255.255.255.252 | /31 | 2 | 255.255.255.254 | /32 | 1 | 255.255.255.255 |