Networking
Spot it
Spot the Subnetting Mistake
Can you spot the mistake before the red stamp lands?
Quick check · tap an answer to continue
Lesson notes
Key points
- A /27 mask is 255.255.255.224, so five host bits remain.
- Block size is 256 minus 224, which equals 32.
- Subnets start at 0, 32, 64, 96, so 77 sits in the 96 subnet.
- Broadcast is one below the next subnet start.
Takeaway: Pick the largest block start that does not exceed the host value.
Quick check: Which step is wrong?
- Step 1
- Step 2
- Step 3
77 is below 96, so it belongs to the subnet starting at 64, not 96.
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