Cisco Certified Support Technician (CCST) Networking 100-150 Practice Test 32
Question 310
An incident reviewer analyzes this observation: At the fictional Oakside Warehouse during basic configuration verification, the team observes: An engineer expects an IPv6 host to ARP for a neighbor's MAC address exactly as IPv4 does. What is the MOST specific underlying cause?
- IPv6 uses Neighbor Discovery with ICMPv6 rather than the IPv4 ARP protocol.
- With a /24 mask their network prefixes are different and communication normally needs Layer 3 forwarding.
- Public addressing requires a legitimately assigned routable prefix or translation, not only an outbound static route.
- 8.8.8.8 is publicly addressed while 192.168.1.10 belongs to private RFC 1918 space.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Oakside Warehouse: IPv6 uses Neighbor Discovery with ICMPv6 rather than the IPv4 ARP protocol. The corresponding remedy is “Check neighbor solicitation and advertisement traffic for the IPv6 peer on the local link.”. Confirmation: The neighbor cache shows the resolved link-layer address after ICMPv6 discovery.
Incorrect Answers
B:That cause belongs to a different case: Two laptops use 192.168.2.20/24 and 192.168.3.20/24; the technician treats them as directly on-link because both addresses begin 192.168. The observed fictional Oakside Warehouse condition is specifically explained by “IPv6 uses Neighbor Discovery with ICMPv6 rather than the IPv4 ARP protocol.”.
C:That cause belongs to a different case: A support analyst believes an internal 192.168.50.0/24 address can be made public solely by changing the router's default route. The observed fictional Oakside Warehouse condition is specifically explained by “IPv6 uses Neighbor Discovery with ICMPv6 rather than the IPv4 ARP protocol.”.
D:That cause belongs to a different case: A network drawing marks 8.8.8.8 and 192.168.1.10 as the same address-scope type for internet routing. The observed fictional Oakside Warehouse condition is specifically explained by “IPv6 uses Neighbor Discovery with ICMPv6 rather than the IPv4 ARP protocol.”.
Question 311
After an approved correction, the support team reviews: At the fictional Oakside Warehouse during basic configuration verification, the team observes: An engineer expects an IPv6 host to ARP for a neighbor's MAC address exactly as IPv4 does. The approved corrective action is: “Check neighbor solicitation and advertisement traffic for the IPv6 peer on the local link.” Which result BEST demonstrates success?
- The computed network and host range follow /27, not an assumed classful /24.
- The printer uses a valid host IP and neither the network nor broadcast address is allocated to equipment.
- Clients reach the actual server while 127.0.0.1 continues to reference each client's own machine.
- The neighbor cache shows the resolved link-layer address after ICMPv6 discovery.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Check neighbor solicitation and advertisement traffic for the IPv6 peer on the local link.” at the fictional Oakside Warehouse. It demonstrates correction of the original cause: IPv6 uses Neighbor Discovery with ICMPv6 rather than the IPv4 ARP protocol.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Use the configured /27 prefix and corresponding mask for the subnet calculation.”. It does not establish the intended outcome “The neighbor cache shows the resolved link-layer address after ICMPv6 discovery.” for the fictional Oakside Warehouse case.
B:That result is evidence for a separate corrective action, “Assign the printer one of 10.8.12.73 through 10.8.12.78 instead.”. It does not establish the intended outcome “The neighbor cache shows the resolved link-layer address after ICMPv6 discovery.” for the fictional Oakside Warehouse case.
C:That result is evidence for a separate corrective action, “Replace client-side loopback targeting with the server's reachable interface name or address.”. It does not establish the intended outcome “The neighbor cache shows the resolved link-layer address after ICMPv6 discovery.” for the fictional Oakside Warehouse case.
Question 312
Before approving the action, review: At the fictional Oakside Warehouse during basic configuration verification, the team observes: An engineer expects an IPv6 host to ARP for a neighbor's MAC address exactly as IPv4 does. During “Check neighbor solicitation and advertisement traffic for the IPv6 peer on the local link.”, which precaution MOST specifically prevents a related risk?
- Do not use a /24 mask with a documented /27 prefix length.
- Do not assign duplicate IPv4 host addresses inside one broadcast domain.
- Do not troubleshoot IPv6 neighbor resolution solely by looking for IPv4 ARP messages.
- Do not assume a 100.70.x.x WAN address is independently public and accepts inbound internet connections.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Check neighbor solicitation and advertisement traffic for the IPv6 peer on the local link.” at the fictional Oakside Warehouse. The required protection is “Do not troubleshoot IPv6 neighbor resolution solely by looking for IPv4 ARP messages.”; success still requires “The neighbor cache shows the resolved link-layer address after ICMPv6 discovery.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: An admin converts /27 to a mask of 255.255.255.0 and allocates too many clients to a tiny segment. The principal adjacent risk here is controlled by “Do not troubleshoot IPv6 neighbor resolution solely by looking for IPv4 ARP messages.”.
B:This caution is appropriate for a separate failure pattern: An office assigns the same IPv4 address to a router interface and a server on one VLAN and the pair has intermittent reachability. The principal adjacent risk here is controlled by “Do not troubleshoot IPv6 neighbor resolution solely by looking for IPv4 ARP messages.”.
D:This caution is appropriate for a separate failure pattern: A guest Wi-Fi laptop shows 100.70.4.9 on the carrier-facing status page and the technician treats it as a customer-owned public IPv4 for inbound hosting. The principal adjacent risk here is controlled by “Do not troubleshoot IPv6 neighbor resolution solely by looking for IPv4 ARP messages.”.
Question 313
A technician reviews the following issue: At the fictional Redwood Repair Shop while assessing a controlled network fault, the team observes: A router carries an IPv6 default route and a trainee writes it as 0.0.0.0/0 in the IPv6 route table. Which action MOST directly resolves the reported issue?
- Use the configured /27 prefix and corresponding mask for the subnet calculation.
- Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.
- Identify .1 as a valid default gateway host and .255 as the broadcast for the subnet.
- Select a /26 block for a conventional single-subnet requirement of at least 50 hosts.
Explanation
Correct Answer
B:Correct. In the fictional Redwood Repair Shop case, IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0. The specified corrective action, “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.”, directly targets that condition. Evidence of resolution: The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.
Incorrect Answers
A:That action addresses a different network issue: A trainee is told an old Class C IPv4 label requires a /24 mask even though a configured interface explicitly uses /27. The present fictional Redwood Repair Shop finding instead needs “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.”, verified by “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.”.
C:That action addresses a different network issue: A LAN router's 192.168.40.1/24 interface is documented as the segment broadcast destination rather than a valid host. The present fictional Redwood Repair Shop finding instead needs “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.”, verified by “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.”.
D:That action addresses a different network issue: A site requests at least 50 usable IPv4 addresses and the trainee chooses a /27 because 32 looks close to 50. The present fictional Redwood Repair Shop finding instead needs “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.”, verified by “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.”.
Question 314
An incident reviewer analyzes this observation: At the fictional Redwood Repair Shop while assessing a controlled network fault, the team observes: A router carries an IPv6 default route and a trainee writes it as 0.0.0.0/0 in the IPv6 route table. What is the MOST specific underlying cause?
- IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0.
- In a /26, .18 is in 192.168.60.0–.63 while .126 is in a different subnet .64–.127.
- Public addressing requires a legitimately assigned routable prefix or translation, not only an outbound static route.
- 10.0.0.0/8 is the private IPv4 block regardless of the apparent decimal value of its octets.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Redwood Repair Shop: IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0. The corresponding remedy is “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.”. Confirmation: The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.
Incorrect Answers
B:That cause belongs to a different case: A remote endpoint uses 192.168.60.18/26 with gateway 192.168.60.126 and cannot leave its LAN. The observed fictional Redwood Repair Shop condition is specifically explained by “IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0.”.
C:That cause belongs to a different case: A support analyst believes an internal 192.168.50.0/24 address can be made public solely by changing the router's default route. The observed fictional Redwood Repair Shop condition is specifically explained by “IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0.”.
D:That cause belongs to a different case: An administrator sees 10.42.7.18 in a lab and calls it a globally assigned public IPv4 address because its first octet is small. The observed fictional Redwood Repair Shop condition is specifically explained by “IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0.”.
Question 315
After an approved correction, the support team reviews: At the fictional Redwood Repair Shop while assessing a controlled network fault, the team observes: A router carries an IPv6 default route and a trainee writes it as 0.0.0.0/0 in the IPv6 route table. The approved corrective action is: “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.” Which result BEST demonstrates success?
- The subnet calculator and manual bitmask agree on the 32-address block size.
- Concurrent clients access internet services and the NAT table tracks distinct translated sessions.
- The resulting subnet has network .128, usable hosts .129–.254 and broadcast .255.
- The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.” at the fictional Redwood Repair Shop. It demonstrates correction of the original cause: IPv6's default route is ::/0, distinct from the IPv4 default 0.0.0.0/0.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Apply 255.255.255.224 and recalculate the subnet's network and broadcast boundaries.”. It does not establish the intended outcome “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.” for the fictional Redwood Repair Shop case.
B:That result is evidence for a separate corrective action, “Configure an approved source NAT/PAT rule and verify outbound connection translations.”. It does not establish the intended outcome “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.” for the fictional Redwood Repair Shop case.
C:That result is evidence for a separate corrective action, “Calculate the /25 network by masking the last octet and choose 192.168.10.128 as the network ID.”. It does not establish the intended outcome “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.” for the fictional Redwood Repair Shop case.
Question 316
Before approving the action, review: At the fictional Redwood Repair Shop while assessing a controlled network fault, the team observes: A router carries an IPv6 default route and a trainee writes it as 0.0.0.0/0 in the IPv6 route table. During “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.”, which precaution MOST specifically prevents a related risk?
- Do not decide global routability by sorting the first IPv4 octet numerically.
- Do not confuse the first usable host with the subnet's broadcast address.
- Do not place an IPv4 default prefix in an IPv6-only routing table.
- Do not use the broader /24 network address when the configured interface is /25.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Use ::/0 with the appropriate IPv6 next hop in the IPv6 routing table.” at the fictional Redwood Repair Shop. The required protection is “Do not place an IPv4 default prefix in an IPv6-only routing table.”; success still requires “The IPv6 forwarding table lists ::/0 and can select it for destinations without a more-specific route.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: An administrator sees 10.42.7.18 in a lab and calls it a globally assigned public IPv4 address because its first octet is small. The principal adjacent risk here is controlled by “Do not place an IPv4 default prefix in an IPv6-only routing table.”.
B:This caution is appropriate for a separate failure pattern: A LAN router's 192.168.40.1/24 interface is documented as the segment broadcast destination rather than a valid host. The principal adjacent risk here is controlled by “Do not place an IPv4 default prefix in an IPv6-only routing table.”.
D:This caution is appropriate for a separate failure pattern: A workstation uses 192.168.10.130/25 and the help desk claims its subnet network address is 192.168.10.0. The principal adjacent risk here is controlled by “Do not place an IPv4 default prefix in an IPv6-only routing table.”.
Question 317
A technician reviews the following issue: At the fictional Millview Retail after a site connectivity report, the team observes: A technician expects IPv6 to send a subnet-wide broadcast address like 192.168.1.255 when contacting all local nodes. Which action MOST directly resolves the reported issue?
- Use the configured /27 prefix and corresponding mask for the subnet calculation.
- Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.
- Investigate the DHCP or static configuration path before relying on the link-local address for routed access.
- Recognize the shared address scope and confirm carrier NAT or dedicated public access requirements.
Explanation
Correct Answer
B:Correct. In the fictional Millview Retail case, IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles. The specified corrective action, “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.”, directly targets that condition. Evidence of resolution: The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.
Incorrect Answers
A:That action addresses a different network issue: A trainee is told an old Class C IPv4 label requires a /24 mask even though a configured interface explicitly uses /27. The present fictional Millview Retail finding instead needs “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.”, verified by “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.”.
C:That action addresses a different network issue: A receptionist reports 169.254.88.2 on a Windows laptop and the team tries to treat it as an ordinary assigned internet WAN address. The present fictional Millview Retail finding instead needs “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.”, verified by “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.”.
D:That action addresses a different network issue: A guest Wi-Fi laptop shows 100.70.4.9 on the carrier-facing status page and the technician treats it as a customer-owned public IPv4 for inbound hosting. The present fictional Millview Retail finding instead needs “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.”, verified by “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.”.
Question 318
An incident reviewer analyzes this observation: At the fictional Millview Retail after a site connectivity report, the team observes: A technician expects IPv6 to send a subnet-wide broadcast address like 192.168.1.255 when contacting all local nodes. What is the MOST specific underlying cause?
- IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles.
- 100.64.0.0/10 is shared address space commonly used for carrier-grade NAT rather than individually public internet addresses.
- Port address translation can map multiple private flows through one public IPv4 using transport port mappings.
- IPv4 127.0.0.0/8 is loopback to the local host, not a remote server reachable from peers.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Millview Retail: IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles. The corresponding remedy is “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.”. Confirmation: The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.
Incorrect Answers
B:That cause belongs to a different case: A guest Wi-Fi laptop shows 100.70.4.9 on the carrier-facing status page and the technician treats it as a customer-owned public IPv4 for inbound hosting. The observed fictional Millview Retail condition is specifically explained by “IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles.”.
C:That cause belongs to a different case: A shared office connects many private IPv4 clients to the internet but expects each to consume a separate public address despite a single ISP-facing IPv4. The observed fictional Millview Retail condition is specifically explained by “IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles.”.
D:That cause belongs to a different case: A developer uses 127.0.0.1 as the server address in an application deployed to other PCs on the LAN. The observed fictional Millview Retail condition is specifically explained by “IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles.”.
Question 319
After an approved correction, the support team reviews: At the fictional Millview Retail after a site connectivity report, the team observes: A technician expects IPv6 to send a subnet-wide broadcast address like 192.168.1.255 when contacting all local nodes. The approved corrective action is: “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.” Which result BEST demonstrates success?
- Concurrent clients access internet services and the NAT table tracks distinct translated sessions.
- An external site sees the approved edge public source while the workstation retains its private address.
- The endpoint can ARP for the gateway and reach an off-subnet test host.
- The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.” at the fictional Millview Retail. It demonstrates correction of the original cause: IPv6 does not use IPv4-style broadcast; multicast serves applicable group communication roles.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Configure an approved source NAT/PAT rule and verify outbound connection translations.”. It does not establish the intended outcome “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.” for the fictional Millview Retail case.
B:That result is evidence for a separate corrective action, “Keep the private prefix internally and arrange approved NAT or public address allocation at the network edge.”. It does not establish the intended outcome “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.” for the fictional Millview Retail case.
C:That result is evidence for a separate corrective action, “Configure a default gateway address within the workstation's 192.168.60.0/26 subnet.”. It does not establish the intended outcome “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.” for the fictional Millview Retail case.
Question 320
Before approving the action, review: At the fictional Millview Retail after a site connectivity report, the team observes: A technician expects IPv6 to send a subnet-wide broadcast address like 192.168.1.255 when contacting all local nodes. During “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.”, which precaution MOST specifically prevents a related risk?
- Do not confuse the first usable host with the subnet's broadcast address.
- Do not claim that a conventional /30 offers four usable host addresses.
- Do not invent a universal IPv6 broadcast address modeled on IPv4 .255.
- Do not decide global routability by sorting the first IPv4 octet numerically.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Identify the appropriate link-local IPv6 multicast group for the intended discovery or group message.” at the fictional Millview Retail. The required protection is “Do not invent a universal IPv6 broadcast address modeled on IPv4 .255.”; success still requires “The capture shows IPv6 multicast delivery instead of a directed or limited broadcast packet.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A LAN router's 192.168.40.1/24 interface is documented as the segment broadcast destination rather than a valid host. The principal adjacent risk here is controlled by “Do not invent a universal IPv6 broadcast address modeled on IPv4 .255.”.
B:This caution is appropriate for a separate failure pattern: A branch requires two usable addresses for a point-to-point IPv4 link and selects /29 without considering the simpler conventional /30. The principal adjacent risk here is controlled by “Do not invent a universal IPv6 broadcast address modeled on IPv4 .255.”.
D:This caution is appropriate for a separate failure pattern: An administrator sees 10.42.7.18 in a lab and calls it a globally assigned public IPv4 address because its first octet is small. The principal adjacent risk here is controlled by “Do not invent a universal IPv6 broadcast address modeled on IPv4 .255.”.