CCNA Network Infrastructure and Connectivity Practice Question
Exhibit
Host IP: 192.168.14.77/27
Exhibit: A host has address 192.168.14.77/27. Which address is its valid default gateway if the first usable address in the subnet is chosen for the router interface?
⚠ Common exam trap
Be careful not to confuse network and broadcast addresses with usable host addresses when identifying a default gateway.
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
✓
192.168.14.65
A /27 has a block size of 32. Address 192.168.14.77 falls in the 192.168.14.64/27 subnet, where the usable host range is 192.168.14.65 through 192.168.14.94. The first usable address is 192.168.14.65.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
192.168.14.63
Why it's wrong here
That is the broadcast address of the previous subnet.
When this WOULD be correct
In a different question where the subnet mask is changed to /26, making the subnet range 192.168.14.0 to 192.168.14.63, option A could be the correct answer if the question specifies that the last usable address is to be used as the default gateway.
- ✗
192.168.14.64
Why it's wrong here
That is the network address of this subnet.
When this WOULD be correct
In a different question setup where the subnet mask is changed to /26, making 192.168.14.64 the first usable address in the new subnet, option B would then be the correct default gateway for hosts within that subnet.
- ✓
192.168.14.65
Why this is correct
That is the first usable address in 192.168.14.64/27.
- ✗
192.168.14.95
Why it's wrong here
That is the broadcast address of this subnet.
When this WOULD be correct
In a different question where the subnet mask is changed to /25, making the subnet range 192.168.14.0 to 192.168.14.127, option D could be correct if the question specifies that the default gateway is to be chosen from the last usable address in that subnet, which would be 192.168.14.126.
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.
✓192.168.14.65Correct answer▾
Why this is correct
That is the first usable address in 192.168.14.64/27.
✗192.168.14.63Wrong answer — click to see why▾
Why this is wrong here
Option A (192.168.14.63) is wrong because it is the last address in the subnet range (192.168.14.64 to 192.168.14.95) and is reserved for the broadcast address, not a valid default gateway.
★ When this WOULD be the correct answer
In a different question where the subnet mask is changed to /26, making the subnet range 192.168.14.0 to 192.168.14.63, option A could be the correct answer if the question specifies that the last usable address is to be used as the default gateway.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of subnetting, confusing the last usable address with the default gateway, especially if they are not fully aware of the reserved addresses in a subnet.
✗192.168.14.64Wrong answer — click to see why▾
Why this is wrong here
Option B, 192.168.14.64, is incorrect because it is the first usable address in the subnet 192.168.14.64/27, which is reserved for the router interface and cannot be assigned as a default gateway for hosts in the subnet.
★ When this WOULD be the correct answer
In a different question setup where the subnet mask is changed to /26, making 192.168.14.64 the first usable address in the new subnet, option B would then be the correct default gateway for hosts within that subnet.
Why candidates choose this
Candidates may choose option B because it is the first address after the subnet's network address, leading to confusion between usable addresses and reserved addresses for router interfaces.
✗192.168.14.95Wrong answer — click to see why▾
Why this is wrong here
Option D, 192.168.14.95, is incorrect because it falls outside the subnet range defined by the 192.168.14.64/27 subnet, which spans from 192.168.14.64 to 192.168.14.94. Thus, it cannot be a valid default gateway for the host in question.
★ When this WOULD be the correct answer
In a different question where the subnet mask is changed to /25, making the subnet range 192.168.14.0 to 192.168.14.127, option D could be correct if the question specifies that the default gateway is to be chosen from the last usable address in that subnet, which would be 192.168.14.126.
Why candidates choose this
Candidates might choose option D due to a misunderstanding of subnetting boundaries, mistakenly believing that any address within a broader range could serve as a valid gateway without considering the specific subnet limits.
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
Quick reference
IPv4 Address Class Summary
| Class | First Octet Range | Default Mask | Networks | Hosts per Network |
|---|---|---|---|---|
| A | 1–126 | /8 (255.0.0.0) | 126 | 16,777,214 |
| B | 128–191 | /16 (255.255.0.0) | 16,384 | 65,534 |
| C | 192–223 | /24 (255.255.255.0) | 2,097,152 | 254 |
| D | 224–239 | N/A | Multicast groups | — |
| E | 240–255 | N/A | Reserved / experimental | — |
127.x.x.x is reserved for loopback. Modern networks use CIDR (classless) rather than classful addressing.
Go deeper
Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
First usable address
The first IP address in a subnet that can be assigned to a host, typically one higher than the network ID.
Key term
Router
A router is a networking device that connects different networks together and directs data traffic between them by choosing the best path for data to travel.
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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.