Interactive DDI tools

Turn network concepts into working answers.

Plan IPv4 space, inspect public DNS, and follow a DHCP lease from discovery through renewal or expiry. Every tool connects the result back to the underlying protocol.

Calculate a subnet Run a DNS lookup

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Start with the question in front of you

Plan address space

IPv4 subnet calculator

Turn an IPv4 address and CIDR prefix into its network, mask, usable range, broadcast address, and subnet plan.

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Inspect public DNS

Live DNS record lookup

Query public DNS records and inspect the answer shape, TTL, priority, and authority data without leaving KnowDDI.

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Follow the lease

DHCP lease lifecycle simulator

Explore DORA, renewal at T1, rebinding at T2, and lease expiry under different server-response scenarios.

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Know the boundary

Useful evidence, not a change to your network

The calculator and simulator run entirely in your browser. DNS lookup asks a public resolver and cannot see private zones, split views, search suffixes, or your organization’s resolver policy.