Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
A network administrator is configuring IP addresses for a new subnet. The network address is 192.168.1.0 with a subnet mask of 255.255.255.240. How many usable host addresses are available on this subnet?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
14
A /28 subnet yields 16 addresses; after removing the network and broadcast addresses, 14 host addresses remain usable.
B
Distractor review
16
16 is the total number of addresses in the subnet, including the network and broadcast addresses, not the usable count.
C
Distractor review
30
30 usable hosts would correspond to a /27 subnet (255.255.255.224).
D
Distractor review
62
62 usable hosts would correspond to a /26 subnet (255.255.255.192).
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
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Question 2
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Question 3
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Question 4
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Question 5
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Question 6
A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?
FAQ
Questions learners often ask
What does this N10-009 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: 14 — The subnet mask 255.255.255.240 corresponds to a /28 prefix, which provides 2^(32-28) = 16 total addresses. Subtracting the network address and broadcast address leaves 14 usable host addresses.
What should I do if I get this N10-009 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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