By ToolzHive · Updated
The three RFC 1918 private blocks can be reused in separate private networks. They are not globally unique public addresses.
Reference table
| Range | CIDR | Classification |
|---|---|---|
| 10.0.0.0 – 10.255.255.255 | 10.0.0.0/8 | Private |
| 172.16.0.0 – 172.31.255.255 | 172.16.0.0/12 | Private |
| 192.168.0.0 – 192.168.255.255 | 192.168.0.0/16 | Private |
| 127.0.0.0 – 127.255.255.255 | 127.0.0.0/8 | Loopback, not RFC 1918 |
| 169.254.0.0 – 169.254.255.255 | 169.254.0.0/16 | Link-local, not RFC 1918 |
| 100.64.0.0 – 100.127.255.255 | 100.64.0.0/10 | Shared space, not RFC 1918 |
Common mistake
172.16.5.8 is private but 172.32.5.8 is outside RFC 1918. Do not classify the whole 172.0.0.0/8 block as private.
Private is not secure
Private addressing provides neither encryption nor access control. Apply firewall rules, authentication and isolation appropriate to the network.
Try the related tools
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