Free Subnetting Drill

10 random CCNA-style subnetting questions, 60 seconds each. Aim: 8+/10 with time to spare. If you can do that, your subnetting is exam-ready.

How it works

Questions cover network address, broadcast address, usable host count and block size for random /24–/30 subnets. Wrong answers show the worked method so every miss is a lesson.

The method (if you need it)

Block size = 256 − interesting octet of the mask. Subnets increment by block size; usable hosts = block size − 2. Network address = the subnet boundary at or below the IP; broadcast = the next boundary minus 1. Full walkthrough: CCNA subnetting cheat sheet and the CIDR cheat sheet.

Subnetting down? Now prove the rest.

The free 25-question CCNA mock test covers the full 200-301 blueprint — routing, switching, security, automation.

Start the free mock test