Keep these common values in your head to speed up your exams: 256 IPs (254 usable) /25: 128 IPs (126 usable) /26: 64 IPs (62 usable) /27: 32 IPs (30 usable) /30: 4 IPs (2 usable) — Used for router-to-router links. 🎓 Ready to test your skills? If you want to dive deeper, I can: Create a practice quiz for you. Explain IPv6 subnetting (it's different!).

In the early days, we used "Classes." This was wasteful and rigid. 255.0.0.0 (/8) — Massive corporations. Class B: 255.255.0.0 (/16) — Universities/Medium biz. Class C: 255.255.255.0 (/24) — Small offices/Homes.

Today, we use . This allows us to put the "slash" anywhere (like /25 or /27), giving us exactly the number of IPs we need. 4. The 5-Step Subnetting Process

Start at .0 and add your magic number repeatedly.

Every device on a network needs a unique identifier: the IP address (IPv4). An IPv4 address is a 32-bit number, usually written in "dotted decimal" format (e.g., 192.168.1.1). The Two Halves of an IP

The is the tool that tells your computer where the street name ends and the house number begins. 2. Understanding Binary (The Secret Language)

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