CCNA Network Infrastructure and Connectivity Practice Question
A subnet has the network address 192.168.30.0/26. What is the broadcast address?
⚠ Common exam trap
Remember that the broadcast address is the last address in the subnet, not the first address of the next subnet or the last usable host address.
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
✓
192.168.30.63
A /26 subnet contains 64 addresses. In plain language, the block that starts at 192.168.30.0 runs through 192.168.30.63. The first address is the network address and the last address is the broadcast address, so the broadcast for this subnet is 192.168.30.63. This is a standard subnet-boundary calculation. Once the block size is identified, the broadcast address is simply the final address in that block.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
192.168.30.63
Why this is correct
The /26 prefix length means 26 network bits, leaving 6 host bits, so the block size is 64 addresses. Since the network address is 192.168.30.0, the usable host range is .1 through .62, and the broadcast address is the last address in the block, which is .63. This is the directed broadcast for this specific /26 subnet.
- ✗
192.168.30.64
Why it's wrong here
.64 is the network address of the next /26 subnet (the block from .64 to .127). It is not part of the .0/26 subnet at all; it is the first address of the subsequent block. Therefore it cannot be the broadcast address for the .0/26 network.
When this WOULD be correct
If the question asked for the first usable IP address of the subnet 192.168.30.0/26, then option B (192.168.30.64) would be correct, as it is the first address of the subsequent subnet after the specified range.
- ✗
192.168.30.255
Why it's wrong here
.255 is the broadcast address for the entire /24 subnet (192.168.30.0/24), which contains four /26 subnets. A /26 broadcast must stay within its own 64-address block; since this /26 block ends at .63, .255 is outside that range and is the broadcast for the parent network, not for this subnet.
When this WOULD be correct
If the question were about a subnet with the network address 192.168.30.0/24, then 192.168.30.255 would be the correct broadcast address, as this subnet includes all addresses from 192.168.30.0 to 192.168.30.255.
- ✗
192.168.30.31
Why it's wrong here
.31 would be the broadcast address if the prefix length were /27, which creates a block size of 32 addresses. The /26 block from .0 spans .0 through .63, so the last address is .63, not .31. A broadcast address must be the final address in the block defined by the prefix length and network address.
When this WOULD be correct
In a different question where the subnet mask is /27, asking for the last usable IP address in the subnet 192.168.30.0/27, option D would be correct as it would then represent the last usable address before the broadcast address of 192.168.30.31.
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.
✓192.168.30.63Correct answer▾
Why this is correct
The /26 prefix length means 26 network bits, leaving 6 host bits, so the block size is 64 addresses. Since the network address is 192.168.30.0, the usable host range is .1 through .62, and the broadcast address is the last address in the block, which is .63. This is the directed broadcast for this specific /26 subnet.
✗192.168.30.64Wrong answer — click to see why▾
Why this is wrong here
Option B is incorrect because the broadcast address for the subnet 192.168.30.0/26 is 192.168.30.63, not 192.168.30.64. The address 192.168.30.64 is actually the first address of the next subnet (192.168.30.64/26).
★ When this WOULD be the correct answer
If the question asked for the first usable IP address of the subnet 192.168.30.0/26, then option B (192.168.30.64) would be correct, as it is the first address of the subsequent subnet after the specified range.
Why candidates choose this
Candidates may choose option B due to confusion between the broadcast address and the first address of the next subnet, especially if they misinterpret the subnetting boundaries.
✗192.168.30.255Wrong answer — click to see why▾
Why this is wrong here
The address 192.168.30.255 is incorrect as the broadcast address for the subnet 192.168.30.0/26, which only spans IPs from 192.168.30.0 to 192.168.30.63. The broadcast address for this subnet is 192.168.30.63.
★ When this WOULD be the correct answer
If the question were about a subnet with the network address 192.168.30.0/24, then 192.168.30.255 would be the correct broadcast address, as this subnet includes all addresses from 192.168.30.0 to 192.168.30.255.
Why candidates choose this
Candidates may choose this option due to familiarity with the concept of broadcast addresses, mistakenly assuming that the highest address in any subnet is always the broadcast address without considering the subnet mask.
✗192.168.30.31Wrong answer — click to see why▾
Why this is wrong here
Option D, 192.168.30.31, is incorrect because it represents the last usable IP address in the subnet 192.168.30.0/26, not the broadcast address. The broadcast address for this subnet is 192.168.30.63.
★ When this WOULD be the correct answer
In a different question where the subnet mask is /27, asking for the last usable IP address in the subnet 192.168.30.0/27, option D would be correct as it would then represent the last usable address before the broadcast address of 192.168.30.31.
Why candidates choose this
Candidates may choose option D due to confusion between the last usable IP address and the broadcast address, especially if they misinterpret the subnetting details or overlook the specific range of usable addresses.
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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Related to this question
Learn chapter
IPv4 Addressing and Address Classes
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
Block size
Block size is the amount of data, measured in bytes, that a system reads or writes in a single operation, affecting storage efficiency and network performance.
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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.