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Subnetting Practice Questions
Free, unlimited subnetting practice. Each problem gives you a random IPv4 address and CIDR prefix; solve for the network address, broadcast address, and usable host count, then check your work or reveal the full worked answer. This is the fastest way to build the subnetting speed the CCNA exam demands.
Practice problem
Score: 0 / 0
Given 192.168.10.0/26, find the network address, broadcast address, and number of usable hosts.
How to use the practice generator
- Read the IP address and CIDR prefix in the problem.
- Work out the network address, broadcast address, and usable host count by hand.
- Type your answers and select Check answer for instant per-field feedback.
- Reveal the worked answer to compare the method, then generate a new problem.
- Need to verify a one-off calculation? Use the subnet calculator or read the subnetting guide.
Frequently asked questions
How do I practice subnetting for the CCNA?
Work random problems under time pressure until the method is automatic. For each problem, find the block size (256 minus the mask octet), round the host octet down to the nearest block boundary for the network address, add the block size minus one for the broadcast, and subtract two from the total addresses for usable hosts. This generator gives you unlimited fresh problems and checks every answer.
What is the fastest way to subnet by hand?
Use the magic-number method. The magic number is 256 minus the relevant mask octet, which is also the block size. Network boundaries fall on multiples of the block size, the broadcast is one below the next boundary, and usable hosts are two less than the block of addresses. With practice you can do most CCNA subnetting questions in under 20 seconds, no binary required.
How many subnetting questions should I do before the exam?
Most candidates need a few hundred reps before subnetting feels automatic. Aim for 20 to 30 correct problems per session across different prefix lengths, and keep going until you can find the network, broadcast, and usable host count without hesitation. Speed matters because the CCNA is time-limited.
Does this cover VLSM and the /31 and /32 edge cases?
The generator produces prefixes from /9 to /30, which is the range you will use for VLSM design and most exam questions. The companion subnet calculator handles every prefix from /0 to /32, including the /31 point-to-point case (RFC 3021) and the /32 single host.
Want subnetting taught live?
Subnetting is one module of CISNET's instructor-led CCNA training. You get guided labs, the fast manual method, and exam-style drills with an instructor who answers your questions in real time.
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