This 200-301 practice question tests your understanding of network infrastructure and connectivity. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: /28 subnet mask equals 255.255.255.240. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A host address is 10.77.4.141/28. Which address is the network address of the subnet?
10.77.4.128
This is correct because .141 is in the 128-143 /28 subnet.
10.77.4.143
Why wrong: This is wrong because .143 is the broadcast address of the subnet.
10.77.4.144
Why wrong: This is wrong because .144 starts the next /28 subnet.
10.77.4.112
Why wrong: This is wrong because .112 belongs to an earlier /28 block.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
10.77.4.128
A /28 subnet has a block size of 16. In practical terms, the last-octet blocks are 0-15, 16-31, 32-47, and so on. Because 141 falls within the 128-143 block, the network address is 10.77.4.128. This is a clean addressing-boundary question that rewards careful block calculation rather than guesswork.
Key principle: /28 subnet mask equals 255.255.255.240
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
10.77.4.128
Why this is correct
This is correct because .141 is in the 128-143 /28 subnet.
Related concept
/28 subnet mask equals 255.255.255.240
10.77.4.143
Why it's wrong here
This is wrong because .143 is the broadcast address of the subnet.
When this WOULD be correct
In a different question where the task is to identify the last usable host address in the subnet, 10.77.4.143 would be correct, as it is the highest address before the broadcast address of 10.77.4.143 in a /28 subnet.
10.77.4.144
Why it's wrong here
This is wrong because .144 starts the next /28 subnet.
When this WOULD be correct
If the question asked for the first usable host address in the subnet instead of the network address, then 10.77.4.144 could be considered correct, as it is the first address after the network address (10.77.4.128) and before the broadcast address (10.77.4.143).
10.77.4.112
Why it's wrong here
This is wrong because .112 belongs to an earlier /28 block.
When this WOULD be correct
In a different question where the subnet mask was /24 and the host address was 10.77.4.112/24, option D would be the correct answer as it would represent the network address for that subnet, which spans from 10.77.4.0 to 10.77.4.255.
Option-by-option analysis
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
Why this is correct
This is correct because .141 is in the 128-143 /28 subnet.
Why this is wrong here
Option B, 10.77.4.143, is incorrect because it falls within the usable host range of the subnet defined by 10.77.4.128/28, which spans from 10.77.4.129 to 10.77.4.142. The network address must always be the first address in the subnet.
★ When this WOULD be the correct answer
In a different question where the task is to identify the last usable host address in the subnet, 10.77.4.143 would be correct, as it is the highest address before the broadcast address of 10.77.4.143 in a /28 subnet.
Why candidates choose this
Candidates may choose this option because it is close to the network address and may confuse it with a valid host address, especially if they misinterpret the subnetting boundaries.
Why this is wrong here
This option is wrong because 10.77.4.144 is not the network address for the subnet defined by 10.77.4.141/28; the correct network address is 10.77.4.128, which is the first address in the subnet range.
★ When this WOULD be the correct answer
If the question asked for the first usable host address in the subnet instead of the network address, then 10.77.4.144 could be considered correct, as it is the first address after the network address (10.77.4.128) and before the broadcast address (10.77.4.143).
Why candidates choose this
Candidates may choose this option due to confusion between the network address and the first usable host address, especially if they misinterpret the subnetting concept or overlook the specifics of address allocation.
Why this is wrong here
Option D, 10.77.4.112, is incorrect because it does not fall within the subnet defined by the CIDR notation /28, which covers addresses from 10.77.4.128 to 10.77.4.143. The network address for this subnet is 10.77.4.128.
★ When this WOULD be the correct answer
In a different question where the subnet mask was /24 and the host address was 10.77.4.112/24, option D would be the correct answer as it would represent the network address for that subnet, which spans from 10.77.4.0 to 10.77.4.255.
Why candidates choose this
Candidates might choose option D due to a misunderstanding of subnetting, confusing the range of usable addresses with the network address, especially if they miscalculate the subnet boundaries.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Be careful not to confuse host addresses with network addresses. Always calculate the subnet block to find the network address.
Detailed technical explanation
A /28 subnet mask corresponds to 255.255.255.240, which means 28 bits are fixed for the network and 4 bits are left for host addressing. The block size is calculated as 256 minus the last octet of the subnet mask (256 - 240 = 16). This divides the IP address space into subnets with 16 addresses each. The network address is the first IP in the block, the broadcast address is the last IP, and the usable hosts are the IPs in between. For the IP 10.77.4.141/28, you determine the subnet by finding which 16-address block contains 141. Since 128 to 143 is one such block, 10.77.4.128 is the network address, 10.77.4.143 is the broadcast, and 10.77.4.129 through 10.77.4.142 are usable host addresses. Understanding this calculation is crucial for subnetting questions on the CCNA exam.
Key takeaway
/28 subnet mask equals 255.255.255.240
Real-world example
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
Review /28 subnet mask equals 255.255.255.240, then practise related 200-301 questions on the same topic to reinforce the concept.
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FAQ
Network Infrastructure and Connectivity — This question tests Network Infrastructure and Connectivity — /28 subnet mask equals 255.255.255.240.
The correct answer is: 10.77.4.128 — A /28 subnet has a block size of 16. In practical terms, the last-octet blocks are 0-15, 16-31, 32-47, and so on. Because 141 falls within the 128-143 block, the network address is 10.77.4.128. This is a clean addressing-boundary question that rewards careful block calculation rather than guesswork.
Review /28 subnet mask equals 255.255.255.240, then practise related 200-301 questions on the same topic to reinforce the concept.
/28 subnet mask equals 255.255.255.240
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Last reviewed: May 17, 2026
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