Topic 03 Practice Test 1 covers IPv4 Addressing, Subnetting, and Private Addressing for Cisco Certified Network Associate 200-301 CCNA and maps to objectives 1.6–1.7. For broader exam preparation, review the Cisco CCNA 200-301 Exam Dumps. Every option includes focused technical reasoning explaining both the networking concept and its fit to the scenario.
Question 1
At Cedar, Nia validates the Atlas cutover under change CHG-2400. A technician is documenting subnet 192.168.10.64/27, which contains host 192.168.10.77. What is the directed broadcast address for this subnet? Choose ONE.
- 192.168.10.64
- 192.168.10.65
- 192.168.10.94
- 192.168.10.95
Correct Answer: D
Correct Answer
Answer D is correct because For 192.168.10.64/27, setting every host bit to one produces 192.168.10.95. That value is reserved as the directed broadcast address for the subnet. This matters during verification because the configured value determines the device behavior being tested.
Incorrect Answers
Answer A is incorrect because 192.168.10.64 is the network address with all host bits zero. The question asks for the opposite boundary value, where the host portion is all ones. This is the relevant behavior an administrator would confirm before accepting the change.
Answer B is incorrect because 192.168.10.65 falls inside the usable host range 192.168.10.65 through 192.168.10.94. A usable endpoint address is not the directed broadcast address. The operational distinction is visible in the resulting interface, address, or forwarding state.
Answer C is incorrect because 192.168.10.94 falls inside the usable host range 192.168.10.65 through 192.168.10.94. A usable endpoint address is not the directed broadcast address. A correct implementation must satisfy that property rather than a superficially similar one.
Question 2
The Helix migration at Juniper is in pre-check, and Mei owns ticket CHG-2413. An engineer reserves the first usable IPv4 address in 10.20.4.128/26 for the default gateway. Which address should be assigned? Choose ONE.
- 10.20.4.129
- 10.20.4.128
- 10.20.4.191
- 10.20.4.190
Correct Answer: A
Correct Answer
Answer A is correct because The network address is 10.20.4.128, so the next address, 10.20.4.129, is the first usable host. That makes it suitable for the gateway reservation described. The device applies the relevant rule to the stated values, which determines the outcome.
Incorrect Answers
Answer B is incorrect because 10.20.4.128 identifies the subnet itself. A network ID cannot be assigned to the gateway interface as a host address. The requested outcome follows from the protocol rule being exercised in this scenario.
Answer C is incorrect because 10.20.4.191 is the directed broadcast address. It is reserved for reaching all hosts on the subnet and cannot be assigned to the gateway. That distinction prevents a valid-looking alternative from meeting the actual requirement.
Answer D is incorrect because 10.20.4.190 is usable but it is the last host in the subnet. The requirement specifically reserves the first usable address, not merely any valid host address. The device evaluates this property directly when it performs the relevant lookup or interface operation.
Question 3
During Maple’s Orbit maintenance window, Maya performs the network acceptance test for CHG-2426. A branch router interface is configured as 172.16.8.9/28. During an addressing review, which IPv4 address is the subnet ID for that interface? Choose ONE.
- 172.16.8.14
- 172.16.8.0
- 172.16.8.15
- 172.16.8.1
Correct Answer: B
Correct Answer
Answer B is correct because Applying the /28 prefix to 172.16.8.9 leaves network address 172.16.8.0. A subnet ID has all host bits set to zero, so it identifies the subnet rather than an endpoint.
Incorrect Answers
Answer C is incorrect because 172.16.8.15 is the directed broadcast address for 172.16.8.0/28. Its host bits are all ones, so it cannot be the subnet ID being requested. The scenario therefore hinges on the specific protocol behavior, not merely on a plausible value.
Answer D is incorrect because 172.16.8.1 is a usable host address inside 172.16.8.0/28. Usable host addresses have a nonzero host portion and therefore do not identify the subnet itself. This is the property an engineer would confirm during an implementation or troubleshooting check.
Answer A is incorrect because 172.16.8.14 is a usable host address inside 172.16.8.0/28. Usable host addresses have a nonzero host portion and therefore do not identify the subnet itself. This choice aligns with both the protocol rule and the operational condition being tested.
Question 4
For ticket CHG-2439, Vikram is reviewing the Vector rollout at the Harbor site. A technician is documenting subnet 198.51.100.16/29, which contains host 198.51.100.19. What is the directed broadcast address for this subnet? Choose ONE.
- 198.51.100.17
- 198.51.100.22
- 198.51.100.23
- 198.51.100.16
Correct Answer: C
Correct Answer
Answer C is correct because For 198.51.100.16/29, setting every host bit to one produces 198.51.100.23. That value is reserved as the directed broadcast address for the subnet. The relevant state can be verified from the protocol information and configuration described here.
Incorrect Answers
Answer D is incorrect because 198.51.100.16 is the network address with all host bits zero. The question asks for the opposite boundary value, where the host portion is all ones. The alternative fails because the operational result differs from what the scenario explicitly requires.
Answer A is incorrect because 198.51.100.17 falls inside the usable host range 198.51.100.17 through 198.51.100.22. A usable endpoint address is not the directed broadcast address. This is the relevant behavior an administrator would confirm before accepting the change.
Answer B is incorrect because 198.51.100.22 falls inside the usable host range 198.51.100.17 through 198.51.100.22. A usable endpoint address is not the directed broadcast address. The protocol rule makes this distinction observable during configuration validation and troubleshooting.
Question 5
Before Summit hands the Cascade service to operations, June must close verification item CHG-2452. A new user VLAN must support at least 29 simultaneously addressed endpoints, and the engineer wants the smallest conventional IPv4 subnet that meets the requirement. Which prefix length should be used? Choose ONE.
- /28
- /26
- /29
- /27
Correct Answer: D
Correct Answer
Answer D is correct because A /27 leaves 5 host bits, giving 30 usable host addresses after the network and broadcast addresses. 30 meets the 29-host requirement while using the longest prefix that still has enough capacity.
Incorrect Answers
Answer A is incorrect because A /28 provides only 14 usable host addresses. That capacity is below the endpoint requirement, so the design would exhaust its usable addresses. The implementation must match this protocol property to satisfy the scenario’s requirement.
Answer B is incorrect because A /26 provides 62 usable host addresses. It would work, but it is larger than necessary because /27 already satisfies the 29-host requirement. The correct choice aligns both with the configured state and with the resulting network behavior.
Answer C is incorrect because A /29 provides only 6 usable host addresses. The usable-host count is insufficient for the stated population and would leave some endpoints without an address. This difference is important because the same device can treat otherwise similar values in different ways.
Question 6
A peer review for Junction at Canyon assigns Talia the evidence check recorded as CHG-2465. A new user VLAN must support at least 50 simultaneously addressed endpoints, and the engineer wants the smallest conventional IPv4 subnet that meets the requirement. Which prefix length should be used? Choose ONE.
- /26
- /27
- /25
- /28
Correct Answer: A
Correct Answer
Answer A is correct because A /26 leaves 6 host bits, giving 62 usable host addresses after the network and broadcast addresses. 62 meets the 50-host requirement while using the longest prefix that still has enough capacity.
Incorrect Answers
Answer B is incorrect because A /27 provides only 30 usable host addresses. Because this subnet supports fewer hosts than required, it cannot satisfy the VLAN capacity target. The scenario tests that exact distinction as it would appear during a practical verification workflow.
Answer C is incorrect because A /25 provides 126 usable host addresses. It would work, but it is larger than necessary because /26 already satisfies the 50-host requirement. The expected result follows from the device state and protocol semantics given in the question.
Answer D is incorrect because A /28 provides only 14 usable host addresses. The host range is too small for the requested endpoint count, making this prefix unsuitable. The engineer must match the requested behavior, not just choose a value that is generally valid elsewhere.
Question 7
The Riverbend branch is staging Quantum; Amina is completing the implementation checklist for CHG-2478. A new user VLAN must support at least 100 simultaneously addressed endpoints, and the engineer wants the smallest conventional IPv4 subnet that meets the requirement. Which prefix length should be used? Choose ONE.
- /27
- /25
- /26
- /24
Correct Answer: B
Correct Answer
Answer B is correct because A /25 leaves 7 host bits, giving 126 usable host addresses after the network and broadcast addresses. 126 meets the 100-host requirement while using the longest prefix that still has enough capacity.
Incorrect Answers
Answer C is incorrect because A /26 provides only 62 usable host addresses. That capacity is below the endpoint requirement, so the design would exhaust its usable addresses. This criterion is what separates the correct operational result from the other plausible alternatives.
Answer D is incorrect because A /24 provides 254 usable host addresses. It would work, but it is larger than necessary because /25 already satisfies the 100-host requirement. The network device applies this rule consistently when processing the described configuration or traffic.
Answer A is incorrect because A /27 provides only 30 usable host addresses. The usable-host count is insufficient for the stated population and would leave some endpoints without an address. That behavior is consistent with the configuration evidence supplied in the question.
Question 8
As part of Xray readiness at Lakeside, Marco investigates the condition logged in CHG-2491. A Cisco interface must be configured with prefix length /27. Which dotted-decimal subnet mask represents that prefix? Choose ONE.
- 255.255.255.252
- 255.255.254.0
- 255.255.255.224
- 255.255.255.248
Correct Answer: C
Correct Answer
Answer C is correct because A /27 prefix contains 27 one-bits in the mask, which converts to 255.255.255.224. Cisco IOS accepts the dotted-decimal mask with the IPv4 interface address, so this value preserves the intended prefix.
Incorrect Answers
Answer D is incorrect because 255.255.255.248 corresponds to /29, not /27. That mask changes the subnet boundary, which also changes the network address, broadcast address, and usable host interval. The outcome is determined by the stated addressing or forwarding condition rather than by naming convention.
Answer A is incorrect because 255.255.255.252 corresponds to /30, not /27. Using this mask would define a different subnet and consequently a different broadcast and host range. The operational outcome follows directly from the configuration and protocol behavior described here.
Answer B is incorrect because 255.255.254.0 corresponds to /23, not /27. The prefix represented by this mask does not match the requested boundary, so the resulting network and host limits would differ. The scenario requires that exact behavior rather than a generally related network concept.
Question 9
Operations at Westfield asks Elena to validate Engine before approving change CHG-2504. A Cisco interface must be configured with prefix length /26. Which dotted-decimal subnet mask represents that prefix? Choose ONE.
- 255.255.252.0
- 255.255.248.0
- 255.255.240.0
- 255.255.255.192
Correct Answer: D
Correct Answer
Answer D is correct because A /26 prefix contains 26 one-bits in the mask, which converts to 255.255.255.192. Cisco IOS accepts the dotted-decimal mask with the IPv4 interface address, so this value preserves the intended prefix.
Incorrect Answers
Answer A is incorrect because 255.255.252.0 corresponds to /22, not /26. That mask changes the subnet boundary, which also changes the network address, broadcast address, and usable host interval. The network behavior is determined by this rule when the stated values are applied.
Answer B is incorrect because 255.255.248.0 corresponds to /21, not /26. Using this mask would define a different subnet and consequently a different broadcast and host range. That makes the option unsuitable for this specific verification goal even if it is valid in another context.
Answer C is incorrect because 255.255.240.0 corresponds to /20, not /26. The prefix represented by this mask does not match the requested boundary, so the resulting network and host limits would differ. This matters during verification because the configured value determines the device behavior being tested.
Question 10
The Drift deployment at Eastgate has reached its verification gate; Mateo is handling CHG-2517. A Cisco interface must be configured with prefix length /29. Which dotted-decimal subnet mask represents that prefix? Choose ONE.
- 255.255.255.248
- 255.255.255.0
- 255.255.255.128
- 255.255.255.192
Correct Answer: A
Correct Answer
Answer A is correct because A /29 prefix contains 29 one-bits in the mask, which converts to 255.255.255.248. Cisco IOS accepts the dotted-decimal mask with the IPv4 interface address, so this value preserves the intended prefix.
Incorrect Answers
Answer B is incorrect because 255.255.255.0 corresponds to /24, not /29. That mask changes the subnet boundary, which also changes the network address, broadcast address, and usable host interval. The operational distinction is visible in the resulting interface, address, or forwarding state.
Answer C is incorrect because 255.255.255.128 corresponds to /25, not /29. Using this mask would define a different subnet and consequently a different broadcast and host range. A correct implementation must satisfy that property rather than a superficially similar one.
Answer D is incorrect because 255.255.255.192 corresponds to /26, not /29. The prefix represented by this mask does not match the requested boundary, so the resulting network and host limits would differ. The requested outcome follows from the protocol rule being exercised in this scenario.
Question 11
At the Northpoint office, Salim checks a Keystone design assumption while processing CHG-2530. An inventory report lists IPv4 address 10.44.7.9. How should the address be classified for RFC 1918 private-addressing purposes? Choose ONE.
- IPv4 subnet ID
- Private IPv4 address covered by RFC 1918
- Public IPv4 address
- IPv4 directed broadcast address
Correct Answer: B
Correct Answer
Answer B is correct because RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 for private internets. 10.44.7.9 falls inside one of those reserved blocks. That distinction prevents a valid-looking alternative from meeting the actual requirement.
Incorrect Answers
Answer C is incorrect because An IPv4 address outside the RFC 1918 private blocks is not private merely because it is used inside an organization. 10.44.7.9 is inside a private block, so treating it as public would misclassify the address.
Answer D is incorrect because A directed broadcast is the all-host-bits-one address for a particular subnet, which cannot be decided from a private/public label alone. The scenario asks about address scope; 10.44.7.9 is being classified against RFC 1918 rather than against a specific subnet boundary.
Answer A is incorrect because A subnet ID has all host bits zero for a known prefix and identifies one network rather than private-address scope. No prefix boundary is supplied that makes subnet-ID classification the relevant decision for 10.44.7.9.
Question 12
Change CHG-2543 covers the Relay network at Southridge, where Omar is the assigned verifier. An inventory report lists IPv4 address 172.15.9.2. How should the address be classified for RFC 1918 private-addressing purposes? Choose ONE.
- IPv4 subnet ID
- Private IPv4 address covered by RFC 1918
- Public IPv4 address
- IPv4 directed broadcast address
Correct Answer: C
Correct Answer
Answer C is correct because An IPv4 address outside the RFC 1918 private blocks is not private merely because it is used inside an organization. 172.15.9.2 is outside 10/8, 172.16/12, and 192.168/16, so this classification matches the scope.
Incorrect Answers
Answer B is incorrect because RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 for private internets. 172.15.9.2 does not fall inside any of those three blocks.
Answer D is incorrect because A directed broadcast is the all-host-bits-one address for a particular subnet, which cannot be decided from a private/public label alone. The scenario asks about address scope; 172.15.9.2 is being classified against RFC 1918 rather than against a specific subnet boundary.
Answer A is incorrect because A subnet ID has all host bits zero for a known prefix and identifies one network rather than private-address scope. No prefix boundary is supplied that makes subnet-ID classification the relevant decision for 172.15.9.2.
Question 13
At Pinecrest, Rosa validates the Yonder cutover under change CHG-2556. An inventory report lists IPv4 address 192.168.200.4. How should the address be classified for RFC 1918 private-addressing purposes? Choose ONE.
- Public IPv4 address
- IPv4 directed broadcast address
- IPv4 subnet ID
- Private IPv4 address covered by RFC 1918
Correct Answer: D
Correct Answer
Answer D is correct because RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 for private internets. 192.168.200.4 falls inside one of those reserved blocks. The device evaluates this property directly when it performs the relevant lookup or interface operation.
Incorrect Answers
Answer A is incorrect because An IPv4 address outside the RFC 1918 private blocks is not private merely because it is used inside an organization. 192.168.200.4 is inside a private block, so treating it as public would misclassify the address.
Answer B is incorrect because A directed broadcast is the all-host-bits-one address for a particular subnet, which cannot be decided from a private/public label alone. The scenario asks about address scope; 192.168.200.4 is being classified against RFC 1918 rather than against a specific subnet boundary.
Answer C is incorrect because A subnet ID has all host bits zero for a known prefix and identifies one network rather than private-address scope. No prefix boundary is supplied that makes subnet-ID classification the relevant decision for 192.168.200.4.
Question 14
The Frontier migration at Brookhaven is in pre-check, and Dario owns ticket CHG-2569. Two hosts are configured as 192.168.1.10/26 and 192.168.1.62/26. What does the subnet calculation show? Choose ONE.
- They are in the same IPv4 subnet
- They are in different IPv4 subnets
- The result depends only on the default gateway
- The result depends on the switch MAC table
Correct Answer: A
Correct Answer
Answer A is correct because Applying /26 to 192.168.1.10 gives 192.168.1.0/26, while applying the same prefix to 192.168.1.62 gives 192.168.1.0/26. Both results match, so local subnet delivery is possible without crossing a router.
Incorrect Answers
Answer B is incorrect because The subnet calculation yields 192.168.1.0/26 for 192.168.1.10 and 192.168.1.0/26 for 192.168.1.62. Because the network IDs are identical, classifying the endpoints as separate subnets would be incorrect.
Answer C is incorrect because A default gateway handles off-subnet forwarding; it does not change the subnet derived from an address and its prefix. The address and mask alone are sufficient to derive and compare both IPv4 network IDs.
Answer D is incorrect because The switch MAC table is a Layer 2 port-location database, so it cannot determine an IPv4 subnet boundary. Subnet membership follows by applying the shared prefix to each IPv4 address and comparing the resulting network IDs.
Question 15
During Oakmont’s Matrix maintenance window, Iris performs the network acceptance test for CHG-2582. Two hosts are configured as 192.168.1.63/26 and 192.168.1.65/26. What does the subnet calculation show? Choose ONE.
- They are in the same IPv4 subnet
- They are in different IPv4 subnets
- The result depends only on the default gateway
- The result depends on the switch MAC table
Correct Answer: B
Correct Answer
Answer B is correct because The subnet calculation yields 192.168.1.0/26 for 192.168.1.63 and 192.168.1.64/26 for 192.168.1.65. Because the network IDs differ, a Layer 3 path is required between them.
Incorrect Answers
Answer A is incorrect because Applying /26 to 192.168.1.63 gives 192.168.1.0/26, while applying the same prefix to 192.168.1.65 gives 192.168.1.64/26. The network IDs differ, so they cannot be treated as local peers in the same subnet.
Answer C is incorrect because Subnet membership comes from the IP address and prefix, whereas the gateway is only the next hop for remote destinations. Comparing the network portions requires only the two addresses and their shared mask.
Answer D is incorrect because MAC-to-port learning is separate from Layer 3 subnet calculation and has no role in deriving the IPv4 network ID. The two IPv4 network IDs come from masking each address with the stated prefix; gateway or MAC state is irrelevant.
Question 16
For ticket CHG-2595, Kiran is reviewing the Transit rollout at the Redstone site. Two hosts are configured as 10.2.8.10/23 and 10.2.9.200/23. What does the subnet calculation show? Choose ONE.
- The result depends only on the default gateway
- The result depends on the switch MAC table
- They are in the same IPv4 subnet
- They are in different IPv4 subnets
Correct Answer: C
Correct Answer
Answer C is correct because Applying /23 to 10.2.8.10 gives 10.2.8.0/23, while applying the same prefix to 10.2.9.200 gives 10.2.8.0/23. Both results match, so local subnet delivery is possible without crossing a router.
Incorrect Answers
Answer D is incorrect because The subnet calculation yields 10.2.8.0/23 for 10.2.8.10 and 10.2.8.0/23 for 10.2.9.200. Because the network IDs are identical, classifying the endpoints as separate subnets would be incorrect.
Answer A is incorrect because A default gateway handles off-subnet forwarding; it does not change the subnet derived from an address and its prefix. The address and mask alone are sufficient to derive and compare both IPv4 network IDs. In the For CHG-2595 Kiran validation, this distinction is directly relevant.
Answer B is incorrect because The switch MAC table is a Layer 2 port-location database, so it cannot determine an IPv4 subnet boundary. Subnet membership follows by applying the shared prefix to each IPv4 address and comparing the resulting network IDs. In the For CHG-2595 Kiran validation, this distinction is directly relevant.
Question 17
Before Silverlake hands the Aperture service to operations, Imran must close verification item CHG-2608. Two hosts are configured as 10.2.10.1/24 and 10.2.11.1/24. What does the subnet calculation show? Choose ONE.
- The result depends only on the default gateway
- The result depends on the switch MAC table
- They are in the same IPv4 subnet
- They are in different IPv4 subnets
Correct Answer: D
Correct Answer
Answer D is correct because The subnet calculation yields 10.2.10.0/24 for 10.2.10.1 and 10.2.11.0/24 for 10.2.11.1. Because the network IDs differ, a Layer 3 path is required between them.
Incorrect Answers
Answer C is incorrect because Applying /24 to 10.2.10.1 gives 10.2.10.0/24, while applying the same prefix to 10.2.11.1 gives 10.2.11.0/24. The network IDs differ, so they cannot be treated as local peers in the same subnet.
Answer A is incorrect because Subnet membership comes from the IP address and prefix, whereas the gateway is only the next hop for remote destinations. Comparing the network portions requires only the two addresses and their shared mask. In the Before Silverlake Aperture validation, this distinction is directly relevant.
Answer B is incorrect because MAC-to-port learning is separate from Layer 3 subnet calculation and has no role in deriving the IPv4 network ID. The two IPv4 network IDs come from masking each address with the stated prefix; gateway or MAC state is irrelevant. In the Before Silverlake Aperture validation, this distinction is directly relevant.
Question 18
A peer review for Harrier at Greenfield assigns Jonas the evidence check recorded as CHG-2621. A router interface must use IPv4 address 192.0.2.17/27. Which Cisco IOS interface command configures the address with the correct mask? Choose ONE.
- ip address 192.0.2.17 255.255.255.224
- ip address 192.0.2.17 255.255.255.240
- ipv6 address 192.0.2.17/27
- ip default-gateway 192.0.2.17
Correct Answer: A
Correct Answer
Answer A is correct because The ip address interface command takes the IPv4 address followed by a dotted-decimal mask; /27 converts to 255.255.255.224. The command therefore assigns the requested host address and preserves the stated /27 subnet boundary.
Incorrect Answers
Answer B is incorrect because 255.255.255.240 represents /28 rather than /27. This would create a smaller subnet and change the network and broadcast boundaries around 192.0.2.17. The scenario therefore hinges on the specific protocol behavior, not merely on a plausible value.
Answer C is incorrect because The ipv6 address command configures IPv6 addressing, not an IPv4 address and dotted-decimal mask. The requested address is IPv4, so using the IPv6 command family is syntactically and operationally wrong. This is the property an engineer would confirm during an implementation or troubleshooting check.
Answer D is incorrect because Ip default-gateway identifies a next-hop gateway on a device that is not routing; it does not assign an address to the interface. The task is to configure the interface itself, so a gateway command cannot satisfy it.
Question 19
The Hillcrest branch is staging Gemini; Anya is completing the implementation checklist for CHG-2634. After assigning IPv4 addresses to several router interfaces, an engineer wants a compact table showing each interface, its IPv4 address, and the interface/protocol state. Which command should be used? Choose ONE.
- show running-config | include hostname
- show ip interface brief
- show mac address-table
- show ipv6 interface brief
Correct Answer: B
Correct Answer
Answer B is correct because Show ip interface brief summarizes interface names, assigned IPv4 addresses, configuration method, interface status, and protocol status. That compact output is designed for exactly this verification task. The relevant state can be verified from the protocol information and configuration described here.
Incorrect Answers
Answer C is incorrect because Show mac address-table displays Layer 2 learned or static MAC entries and their VLAN/port associations. It does not provide the requested routed-interface IPv4 summary. The protocol semantics make this the appropriate interpretation for the values shown.
Answer D is incorrect because Show ipv6 interface brief summarizes IPv6 state and IPv6 addresses. The engineer is validating IPv4 assignments, so the IPv6-specific command is not the requested view. The alternative fails because the operational result differs from what the scenario explicitly requires.
Answer A is incorrect because This filtered configuration view would return hostname-related lines, not a table of interface addresses and states. It therefore cannot efficiently verify the IPv4 addressing requested in the scenario. The resulting device state distinguishes this answer from the related but incorrect alternatives.
Question 20
As part of Nova readiness at Fairview, Yusuf investigates the condition logged in CHG-2647. A router shows GigabitEthernet0/1 as administratively down in show ip interface brief after the correct IPv4 address was configured. Which action is required to enable the interface? Choose ONE.
- Clear the MAC address table
- Configure an IPv6 link-local address
- Enter no shutdown under the interface
- Change the subnet mask to /32
Correct Answer: C
Correct Answer
Answer C is correct because An administratively down state means the interface has been disabled by configuration, commonly with the shutdown command. Removing the administrative shutdown allows the interface hardware state to come up when the physical link is available.
Incorrect Answers
Answer D is incorrect because A /32 mask changes Layer 3 subnet interpretation but does not remove an administrative shutdown. The interface would remain disabled regardless of the configured prefix. The protocol rule makes this distinction observable during configuration validation and troubleshooting.
Answer A is incorrect because Clearing learned Layer 2 addresses affects switching information, not the administrative state of a routed interface. It cannot change an interface from administratively down to enabled. This result can be confirmed from the address, interface, or forwarding information provided.
Answer B is incorrect because Adding IPv6 addressing does not override the configured shutdown state. Administrative enablement must be addressed directly before either IPv4 or IPv6 can operate on the interface. The correct choice aligns both with the configured state and with the resulting network behavior.
