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Reverse DNS Zone Calculator
Calculate traditional, RFC 2317 classless IPv4, and nibble-aligned IPv6 reverse-DNS zones from CIDR.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
Reverse-zone details
| Address family | — |
|---|---|
| Normalized network | — |
| Prefix length | — |
| First address | — |
| Last address | — |
| Reverse zone / owner | — |
| Parent reverse zone | — |
| Result type | — |
How it works
Octet-aligned IPv4 prefixes and nibble-aligned IPv6 prefixes have unambiguous reverse zones. IPv4 /25–/31 blocks are shown with the RFC 2317 range-label convention. Other non-boundary prefixes are reported as unsupported because their delegation convention cannot be inferred from CIDR alone. No DNS lookup is performed.