Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A host address is 192.168.50.158/27. Which address is the network address of its 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
192.168.50.128
This is correct because 158 belongs to the 128-159 /27 subnet.
B
Distractor review
192.168.50.159
This is wrong because .159 is the broadcast address of that subnet.
C
Distractor review
192.168.50.160
This is wrong because .160 starts the next /27 subnet.
D
Distractor review
192.168.50.96
This is wrong because that is the start of an earlier /27 subnet.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is mistaking the broadcast address or the next subnet's network address for the network address itself. For a /27 subnet, the last address in the block is the broadcast address, not the network address. For example, 192.168.50.159 is the broadcast address for the 192.168.50.128/27 subnet, so selecting it as the network address is incorrect. Similarly, 192.168.50.160 is the start of the next subnet, not the current one. Candidates often overlook the block size calculation and assume the network address is the closest or similar IP, leading to errors.
Technical deep dive
How to think about this question
Subnetting is a fundamental concept in IP networking that divides a larger network into smaller, manageable segments called subnets. Each subnet has a network address, a range of usable host addresses, and a broadcast address. The subnet mask determines the size of each subnet by defining how many bits are used for the network portion versus the host portion of the IP address. In this question, the /27 mask means 27 bits are fixed for the network, leaving 5 bits for host addresses, resulting in subnets with 32 IP addresses each. To find the network address of a host IP within a /27 subnet, you calculate the block size as 2^(32-27) = 32 addresses per subnet. The subnets increment in blocks of 32 in the last octet: 0-31, 32-63, 64-95, 96-127, 128-159, and so forth. Since the host IP 192.168.50.158 falls between 128 and 159, the network address is the first IP in that range, 192.168.50.128. This address identifies the subnet and is used by routers and switches to route traffic correctly. A common exam trap is confusing the network address with the broadcast or next subnet address. For example, 192.168.50.159 is the broadcast address for the 192.168.50.128/27 subnet, not the network address. Similarly, 192.168.50.160 is the start of the next subnet. Understanding the block size and correctly identifying the first address in the block as the network address is critical for subnetting questions on the CCNA exam and practical network design.
KKey Concepts to Remember
- A /27 subnet mask uses 27 bits for the network portion, leaving 5 bits for host addresses, resulting in 32 IP addresses per subnet block.
- The network address is always the first IP address in the subnet block and identifies the subnet uniquely for routing purposes.
- The broadcast address is the last IP address in the subnet block and is used to send packets to all hosts in that subnet.
- Subnet blocks increment by the block size in the relevant octet, which is calculated as 2^(32 - subnet mask bits).
- Correct subnet identification requires matching the host IP to the subnet block range and selecting the block's first address as the network address.
- Confusing the broadcast address or the next subnet's network address with the current subnet's network address is a common subnetting mistake.
- Cisco devices use the network address to route packets correctly within and between subnets in an IP network.
- Understanding subnetting block sizes and address ranges is essential for configuring 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.
CCNA subnetting practice questions
Practise IPv4 subnetting, CIDR, masks, host ranges and subnet selection.
CCNA OSPF practice questions
Practise OSPF neighbours, router IDs, metrics, areas and routing-table interpretation.
CCNA VLAN practice questions
Practise VLANs, access ports, trunks, allowed VLANs and switching scenarios.
CCNA STP practice questions
Practise spanning tree, root bridge election, port roles and STP troubleshooting.
CCNA EtherChannel practice questions
Practise LACP, PAgP, port-channel behaviour and bundle requirements.
CCNA ACL practice questions
Practise standard and extended ACLs, permit/deny logic and traffic filtering.
CCNA NAT practice questions
Practise static NAT, dynamic NAT, PAT and inside/outside address translation.
CCNA DHCP practice questions
Practise DHCP scopes, relay, leases and troubleshooting.
CCNA show ip route practice questions
Practise routing-table output, longest-prefix match, AD and route selection.
CCNA show interfaces trunk practice questions
Practise trunk verification and VLAN forwarding across switches.
CCNA wireless security practice questions
Practise WLAN security, authentication and wireless architecture concepts.
CCNA IPv6 practice questions
Practise IPv6 addressing, routes, neighbour discovery and common IPv6 exam traps.
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 /27 subnet mask uses 27 bits for the network portion, leaving 5 bits for host addresses, resulting in 32 IP addresses per subnet block.
What is the correct answer to this question?
The correct answer is: 192.168.50.128 — A /27 subnet has a block size of 32. In practical terms, the relevant ranges in the last octet are 0-31, 32-63, 64-95, 96-127, 128-159, and so on. Because 158 falls in the 128-159 block, the network address is 192.168.50.128. This is a block-identification question. Once you identify the correct /27 block, the network address is the first address in that range.
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.
Discussion
Loading comments…
Sign in to join the discussion.