CCNA Network Infrastructure and Connectivity Practice Question
A host address is 10.100.12.94/26. Which address is the broadcast address for that subnet?
⚠ Common exam trap
Be careful not to confuse host addresses or network addresses with the broadcast address. Remember, the broadcast address is the last address in the subnet range.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
10.100.12.127
A /26 subnet has a block size of 64, so the fourth-octet ranges are 0–63, 64–127, 128–191, and 192–255. The host address 10.100.12.94 lies in the 64–127 range, making the broadcast address the last address in that range: 10.100.12.127. Option A (10.100.12.63) is the broadcast of the previous subnet (0–63). Option C (10.100.12.64) is the network address of the subnet containing the host. Option D (10.100.12.128) is the network address of the next subnet (128–191).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
10.100.12.63
Why it's wrong here
10.100.12.63 is the broadcast of the 10.100.12.0/26 subnet, not the one containing the host. It is tempting because /26 boundaries start at .0, .64, .128 and .192, and it would be correct had the host address fallen within the first subnet.
When this WOULD be correct
In a question where the subnet mask is /26 and the network address is 10.100.12.0, if the question mistakenly states that the subnet ends at 10.100.12.63, then 10.100.12.63 would be the correct broadcast address for that defined range.
- ✓
10.100.12.127
Why this is correct
A /26 mask leaves six host bits, so each subnet spans 64 addresses. The host 10.100.12.94 sits in the block 10.100.12.64–10.100.12.127, whose all-ones host portion yields the broadcast address 10.100.12.127, satisfying the subnet broadcast requirement.
- ✗
10.100.12.64
Why it's wrong here
10.100.12.64 is the network address of the subnet containing 10.100.12.94, not its broadcast. It is tempting because it is the nearest /26 boundary below the host, and it would be correct if the question asked for the subnet identifier rather than the broadcast.
When this WOULD be correct
In a different question setup where the subnet mask is /26 and the network address is 10.100.12.64, option C would be the correct answer if the question asked for the first usable host address instead of the broadcast address.
- ✗
10.100.12.128
Why it's wrong here
10.100.12.128 is the network address of the next /26 subnet, not the broadcast of the host's own subnet. It is tempting because it is the following boundary, and it would be correct as the network address for hosts in the 10.100.12.128/26 range.
When this WOULD be correct
If the question were to ask for the broadcast address of a subnet defined by 10.100.12.128/26, then option D would be correct, as the broadcast address for that subnet would be 10.100.12.191.
Option-by-option analysis
Why each answer is right or wrong
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.
✓10.100.12.127Correct answer▾
Why this is correct
A /26 mask leaves six host bits, so each subnet spans 64 addresses. The host 10.100.12.94 sits in the block 10.100.12.64–10.100.12.127, whose all-ones host portion yields the broadcast address 10.100.12.127, satisfying the subnet broadcast requirement.
✗10.100.12.63Wrong answer — click to see why▾
Why this is wrong here
The address 10.100.12.63 is incorrect as the broadcast address for the subnet 10.100.12.0/26, which actually has a range from 10.100.12.0 to 10.100.12.63. The correct broadcast address for the subnet is 10.100.12.127.
★ When this WOULD be the correct answer
In a question where the subnet mask is /26 and the network address is 10.100.12.0, if the question mistakenly states that the subnet ends at 10.100.12.63, then 10.100.12.63 would be the correct broadcast address for that defined range.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of subnetting, where they incorrectly calculate the broadcast address by only considering the last octet and not accounting for the subnet mask properly.
✗10.100.12.64Wrong answer — click to see why▾
Why this is wrong here
Option C (10.100.12.64) is incorrect because it is the first usable host address in the subnet 10.100.12.64/26, not the broadcast address. The broadcast address for this subnet is 10.100.12.127.
★ When this WOULD be the correct answer
In a different question setup where the subnet mask is /26 and the network address is 10.100.12.64, option C would be the correct answer if the question asked for the first usable host address instead of the broadcast address.
Why candidates choose this
Candidates might choose option C due to confusion between the broadcast address and the first usable address in a subnet, especially if they miscalculate the range of addresses available in a /26 subnet.
✗10.100.12.128Wrong answer — click to see why▾
Why this is wrong here
Option D (10.100.12.128) is incorrect because it does not fall within the range of addresses for the subnet defined by 10.100.12.94/26, which spans from 10.100.12.64 to 10.100.12.127.
★ When this WOULD be the correct answer
If the question were to ask for the broadcast address of a subnet defined by 10.100.12.128/26, then option D would be correct, as the broadcast address for that subnet would be 10.100.12.191.
Why candidates choose this
Candidates may be tempted by option D because it is a common mistake to miscalculate subnet boundaries, especially when dealing with larger subnets or when they misinterpret the CIDR notation.
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?”
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Key term
Subnet
A subnet is a logical subdivision of an IP network, created by partitioning a larger network address space using subnet masks.
Key term
Broadcast address
A broadcast address is a special network address used to send data to every device on a local network segment simultaneously.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.