DNS Toolbox & Record Inspector
Web & network Network on demand
IP, CIDR & Subnet Planner
Local onlyCalculate IPv4 and IPv6 networks, split CIDRs, summarize ranges, and allocate VLSM plans.
Planning arithmetic, not network discovery
The tool does not contact, scan, reserve, route, or verify any address. Validate special-use registries, existing assignments, cloud rules, gateway reservations, redundancy, and future growth before deployment.
How to use it
- 01
Enter an address and prefix
Use IPv4 or IPv6 CIDR notation to inspect the canonical network, address range, capacity, reverse DNS, and classification.
- 02
Plan address space
Split a parent CIDR, convert an inclusive range to minimal CIDRs, or allocate IPv4 VLSM blocks by host requirement.
- 03
Copy or export
Copy individual values and CIDRs or export subnet and VLSM plans as CSV.
Frequently asked questions
Does the tool support IPv6?
Yes. It parses compressed and expanded IPv6, calculates prefixes and ranges, creates reverse-DNS names, classifies common special ranges, and splits prefixes.
How are IPv4 /31 networks handled?
Following RFC 3021 point-to-point semantics, both addresses are counted as usable. A /32 is treated as a single host route.
Does this discover my public IP or scan a network?
No. It performs deterministic local address arithmetic only and sends no IP address to a lookup or scanning service.
Is the VLSM plan router-ready?
It is an allocation aid. Verify reserved addresses, routing policy, cloud-provider rules, redundancy, growth, and existing assignments before deployment.
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