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IPv4 Address Membership
Check which CIDR blocks from a list contain a given IPv4 address, with the longest-prefix match highlighted.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
How it works
Enter one address and a list of CIDR blocks (bare addresses count as /32). Every block that contains the address is listed, sorted by prefix length so the longest-prefix match — the one a router would use — is first. Blocks that do not contain the address are listed separately. Up to 5,000 blocks.