CCNA Network Infrastructure and Connectivity Practice Question
A host is configured with 10.10.10.33/27. What is the broadcast address of its subnet?
⚠ Common exam trap
Don't confuse the network address or the next subnet's start with the broadcast address. Always calculate the correct range first.
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
✓
10.10.10.63
A /27 uses address blocks of 32. In practical terms, the ranges are 0–31, 32–63, 64–95, and so on. Because .33 falls inside the 32–63 block, the broadcast address is the last address in that block, which is 10.10.10.63. This is a classic subnet-boundary question. The trick is to identify the correct block first and then choose its last address as the broadcast.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
10.10.10.31
Why it's wrong here
10.10.10.31 is the broadcast address of the previous /27 subnet, which spans 10.10.10.0 through 10.10.10.31. Because .33 is not in that range—it lies in the next 32-address block starting at .32—the broadcast for .33's subnet cannot be .31. Confusing it with the prior block ignores the subnet boundary at .32, which is why this is incorrect.
When this WOULD be correct
If the question were to ask for the broadcast address of the subnet 10.10.10.0/27, then 10.10.10.31 would be the correct answer, as it is the highest address in that subnet range.
- ✓
10.10.10.63
Why this is correct
10.10.10.63 is correct because the /27 prefix length gives a block size of 2^(32-27)=32 addresses, meaning subnets align on boundaries of 32 in the last octet. The host 10.10.10.33 falls within the 10.10.10.32 to 10.10.10.63 range, and the broadcast address is always the highest (last) address in that subnet block, which is 10.10.10.63. This matches the definition of a directed broadcast for that subnet.
- ✗
10.10.10.32
Why it's wrong here
10.10.10.32 is the network address of the /27 subnet that contains host .33, because a /27 mask divides the fourth octet into 32-address blocks (0-31, 32-63, 64-95...). The network address is always the first address of the block and is reserved to identify the subnet itself, never used as a broadcast. Since .33 falls in the 32-63 block, the broadcast for that block must be the last address, .63, not the first.
When this WOULD be correct
In a different question where the subnet mask is /26 and the host IP is 10.10.10.33, option C (10.10.10.32) would be the correct answer, as it would then represent the network address of that subnet.
- ✗
10.10.10.64
Why it's wrong here
10.10.10.64 is the network address of the following /27 subnet, which covers 10.10.10.64 through 10.10.10.95. Since the host .33 belongs to the 10.10.10.32-63 block, any address in the next block is outside its subnet. The broadcast address must be the last address of the containing block, .63, not the starting address of a subsequent block.
When this WOULD be correct
If the question specified a different subnet mask, such as /26, then the broadcast address would be 10.10.10.63, making option D (10.10.10.64) the next valid address in that subnet, which could be considered for a different context.
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.
✓10.10.10.63Correct answer▾
Why this is correct
10.10.10.63 is correct because the /27 prefix length gives a block size of 2^(32-27)=32 addresses, meaning subnets align on boundaries of 32 in the last octet. The host 10.10.10.33 falls within the 10.10.10.32 to 10.10.10.63 range, and the broadcast address is always the highest (last) address in that subnet block, which is 10.10.10.63. This matches the definition of a directed broadcast for that subnet.
✗10.10.10.31Wrong answer — click to see why▾
Why this is wrong here
10.10.10.31 is the broadcast address of the previous /27 subnet (10.10.10.0–10.10.10.31), not the subnet containing .33.
★ When this WOULD be the correct answer
If the question were to ask for the broadcast address of the subnet 10.10.10.0/27, then 10.10.10.31 would be the correct answer, as it is the highest address in that subnet range.
Why candidates choose this
Students often mistakenly think that because .33 is close to .31, the broadcast might be .31, or they confuse the network address with the broadcast address.
✗10.10.10.32Wrong answer — click to see why▾
Why this is wrong here
10.10.10.32 is the network address (subnet ID) of the subnet containing .33, not the broadcast address. The network address is the first address in the block.
★ When this WOULD be the correct answer
In a different question where the subnet mask is /26 and the host IP is 10.10.10.33, option C (10.10.10.32) would be the correct answer, as it would then represent the network address of that subnet.
Why candidates choose this
Students may incorrectly assume that the network address is the broadcast address, especially when they see that .32 is the start of the subnet and .33 is the first usable host.
✗10.10.10.64Wrong answer — click to see why▾
Why this is wrong here
10.10.10.64 is the network address of the next /27 subnet (10.10.10.64–10.10.10.95), not the broadcast address of the subnet containing .33.
★ When this WOULD be the correct answer
If the question specified a different subnet mask, such as /26, then the broadcast address would be 10.10.10.63, making option D (10.10.10.64) the next valid address in that subnet, which could be considered for a different context.
Why candidates choose this
Students might think that because .33 is near the end of the block, the broadcast could be the next network address, or they may miscalculate the block 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?”
Visual reference
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Related to this question
Learn chapter
IPv4 Addressing and Address Classes
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.
Key term
Subnet
A subnet is a logical subdivision of an IP network, created by partitioning a larger network address space using subnet masks.
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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.