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IP Class Finder

Type any IPv4 address and see its class (A–E), default mask, typical use, and whether it is a private RFC 1918 or public address: live in your browser.

Runs locallyComputed in your browser: nothing is sent anywhere

tools.ipclass runs locally

When you’d reach for this

Classful addressing is officially obsolete (CIDR replaced it), but exams, legacy configs and interview questions still speak in classes. This tool answers “what class is this address, and is it private?” instantly, and the class strip shows you the first-octet ranges worth memorising.

Learn the idea behind the tool

This tool is the fast answer; the lesson is the understanding. Start with IPv4 addressing.

Keep going

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