Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A host address is 192.168.22.145/28. Which subnet contains that host?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
192.168.22.128/28
This is wrong because that block ends at .143.
B
Best answer
192.168.22.144/28
This is correct because .145 falls within the .144 through .159 block.
C
Distractor review
192.168.22.160/28
This is wrong because that block begins above the host address.
D
Distractor review
192.168.22.148/28
This is wrong because /28 boundaries do not start at .148.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is choosing a subnet that seems numerically close to the host address but does not align with the subnet boundary defined by the prefix length. For example, selecting 192.168.22.128/28 because it is near 192.168.22.145 is incorrect since the /28 subnet block ends at .143. This mistake happens when candidates do not calculate the block size or subnet increments properly, leading to misidentification of the correct subnet. The trap exploits familiarity with common subnet numbers rather than precise subnetting calculations.
Technical deep dive
How to think about this question
Subnetting divides an IP network into smaller, manageable segments by borrowing bits from the host portion of the address to create subnetworks. A /28 prefix means the subnet mask is 255.255.255.240, which allocates 28 bits for the network and leaves 4 bits for host addresses. This results in subnets with 16 IP addresses each, including network and broadcast addresses. To determine which subnet contains a given host IP, calculate the subnet block size using the prefix length. For /28, the block size is 16 addresses. Starting from zero, subnets increment by 16 in the fourth octet: 0–15, 16–31, 32–47, and so forth. Since 192.168.22.145 falls between 144 and 159, it belongs to the 192.168.22.144/28 subnet. A common exam trap is selecting a subnet based on a close but incorrect boundary, such as 192.168.22.128/28, which ends at .143 and excludes .145. Understanding subnet boundaries and block sizes is critical in Cisco CCNA subnetting questions to avoid misclassification of host addresses and ensure accurate network segmentation in practical Cisco environments.
KKey Concepts to Remember
- A /28 subnet mask allocates 28 bits to the network portion and leaves 4 bits for host addresses, creating subnets with 16 IP addresses each.
- Subnet blocks increment by the block size derived from the prefix length, which is 16 for a /28 subnet, defining the range of valid host addresses.
- The network address of a subnet is the first IP in the block, and the broadcast address is the last IP in the block, with usable hosts in between.
- To determine the subnet containing a host, calculate the subnet block boundaries and identify the block range that includes the host IP address.
- Incorrectly selecting a subnet that does not align with the calculated block boundaries leads to misclassification of the host’s subnet.
- Cisco CCNA subnetting questions test the ability to convert prefix lengths to block sizes and apply them to real IP address ranges.
- Hosts must fall within the subnet’s valid host address range, which excludes the network and broadcast addresses.
- Understanding subnet boundaries is essential for designing and troubleshooting IP networks in Cisco environments.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Related practice questions
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
A /28 subnet mask allocates 28 bits to the network portion and leaves 4 bits for host addresses, creating subnets with 16 IP addresses each.
What is the correct answer to this question?
The correct answer is: 192.168.22.144/28 — A /28 prefix creates address blocks of 16. In practical terms, the fourth-octet ranges are 0–15, 16–31, 32–47, and so on. Because 145 falls inside the 144–159 range, the network address of the containing subnet is 192.168.22.144/28. This type of question checks whether you can move from prefix length to block size and then place a host into the correct interval. The common mistake is choosing a nearby familiar number instead of calculating the actual block boundary.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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