Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A host is configured as 10.10.20.190/26. Which range contains usable host addresses for that subnet?
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
Best answer
10.10.20.129 to 10.10.20.190
This is correct because that is the usable host range of the 10.10.20.128/26 subnet.
B
Distractor review
10.10.20.128 to 10.10.20.191
This is wrong because those include the network and broadcast addresses.
C
Distractor review
10.10.20.130 to 10.10.20.191
This is wrong because it excludes one valid host and includes the broadcast address.
D
Distractor review
10.10.20.193 to 10.10.20.254
This is wrong because that range belongs to the next subnet block.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting an IP range that includes the network or broadcast address as usable hosts. For example, option B includes 10.10.20.128 (network) and 10.10.20.191 (broadcast), which are never assignable to hosts. Another trap is excluding valid hosts or including the broadcast address, as seen in option C. These mistakes often arise from misunderstanding subnet boundaries or miscalculating the block size. Candidates must carefully identify the subnet block and remember that the first and last addresses are reserved, not usable for hosts.
Technical deep dive
How to think about this question
Subnetting is a fundamental concept in IP networking that allows a single IP network to be divided into multiple smaller networks or subnets. This is done by extending the network mask beyond the default classful mask, borrowing bits from the host portion of the address to create subnet bits. For a /26 subnet mask, which is 255.255.255.192, the network is divided into blocks of 64 IP addresses each. These blocks are contiguous and non-overlapping, allowing efficient address allocation and management. To determine the usable host range within a /26 subnet, you first identify the network address, which is the first IP in the block, and the broadcast address, which is the last IP in the block. Neither of these addresses can be assigned to hosts. For example, the block 10.10.20.128/26 includes addresses from 10.10.20.128 to 10.10.20.191. Here, 10.10.20.128 is the network address, and 10.10.20.191 is the broadcast address. The usable host addresses are therefore from 10.10.20.129 to 10.10.20.190. A common exam trap is confusing the network and broadcast addresses with usable hosts, especially when the host IP is near the subnet boundaries. For instance, including 10.10.20.128 or 10.10.20.191 as usable hosts is incorrect and can cause network issues in real Cisco environments. Practically, Cisco routers and switches enforce these rules strictly, so understanding and correctly identifying subnet ranges and usable hosts is essential for configuring interfaces and troubleshooting IP connectivity problems.
KKey Concepts to Remember
- Subnetting divides an IP address space into smaller blocks by borrowing bits from the host portion to create subnetworks.
- A /26 subnet mask corresponds to 255.255.255.192, which divides an IPv4 Class A, B, or C network into blocks of 64 addresses each.
- The first address in a subnet block is the network address and cannot be assigned to hosts.
- The last address in a subnet block is the broadcast address and is reserved for network-wide communication.
- Usable host addresses are all IPs between the network and broadcast addresses, excluding both.
- To find the subnet block for a host, identify the subnet range that contains the host IP based on the subnet mask.
- Cisco devices use subnetting rules strictly, so assigning network or broadcast addresses to hosts causes connectivity issues.
- Understanding subnet boundaries and usable host ranges is critical for IP address planning and troubleshooting in Cisco networks.
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
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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?
Subnetting divides an IP address space into smaller blocks by borrowing bits from the host portion to create subnetworks.
What is the correct answer to this question?
The correct answer is: 10.10.20.129 to 10.10.20.190 — A /26 uses blocks of 64 addresses. In plain language, the ranges are 0–63, 64–127, 128–191, and 192–255. Since the host ends in 190, it belongs to the 128–191 block. In that block, 10.10.20.128 is the network address and 10.10.20.191 is the broadcast address. That leaves 10.10.20.129 through 10.10.20.190 as the usable host range. This question checks whether you can identify the correct block and then exclude the reserved endpoints properly.
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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