Cisco Certified Support Technician (CCST) Networking 100-150 Practice Test 66
Question 650
The local support team reports: At the fictional Harborline Clinic while assessing a controlled network fault, the team observes: Two PCs connected to one physical switch are in separate access VLANs and cannot talk without routing, but the help desk assumes all switch ports share one broadcast domain. What is the MOST specific underlying cause?
- VLANs separate Layer 2 broadcast domains even on the same physical switch.
- Same-subnet IPv4 destinations normally use direct Layer 2 delivery, not a routed next hop.
- Serial WAN ports and USB peripheral ports have different functions and physical signaling.
- Ethernet data capability does not imply that a given port offers Power over Ethernet.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Harborline Clinic: VLANs separate Layer 2 broadcast domains even on the same physical switch. The corresponding remedy is “Verify port VLAN membership and provide an authorized inter-VLAN routing path if communication is required.”. Confirmation: The VLAN map shows distinct Layer 2 domains and routed connectivity follows approved policy.
Incorrect Answers
B:That cause belongs to a different case: A host sees another device on the same 192.168.7.0/24 segment and sends all packets to its gateway rather than using local neighbor resolution. The observed fictional Harborline Clinic condition is specifically explained by “VLANs separate Layer 2 broadcast domains even on the same physical switch.”.
C:That cause belongs to a different case: A remote site uses a legacy serial WAN interface but a technician attaches a modern USB flash-memory cable expecting it to carry the circuit. The observed fictional Harborline Clinic condition is specifically explained by “VLANs separate Layer 2 broadcast domains even on the same physical switch.”.
D:That cause belongs to a different case: A VoIP phone requires power through its Ethernet cable but a technician connects it to an otherwise working non-PoE Ethernet interface. The observed fictional Harborline Clinic condition is specifically explained by “VLANs separate Layer 2 broadcast domains even on the same physical switch.”.
Question 651
The technician must verify the following scenario: At the fictional Harborline Clinic while assessing a controlled network fault, the team observes: Two PCs connected to one physical switch are in separate access VLANs and cannot talk without routing, but the help desk assumes all switch ports share one broadcast domain. The approved corrective action is: “Verify port VLAN membership and provide an authorized inter-VLAN routing path if communication is required.” Which result BEST demonstrates success?
- Both distribution switches report their intended fiber link operational.
- Optical link and receive levels become healthy on both switch ports.
- The escalation includes the model-specific meaning rather than a universal claim that amber always means failure.
- The VLAN map shows distinct Layer 2 domains and routed connectivity follows approved policy.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Verify port VLAN membership and provide an authorized inter-VLAN routing path if communication is required.” at the fictional Harborline Clinic. It demonstrates correction of the original cause: VLANs separate Layer 2 broadcast domains even on the same physical switch.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Use the specified compatible fiber run and transceivers for the distribution uplink.”. It does not establish the intended outcome “The VLAN map shows distinct Layer 2 domains and routed connectivity follows approved policy.” for the fictional Harborline Clinic case.
B:That result is evidence for a separate corrective action, “Attach the correct LC fiber patch cable to the compatible optical module.”. It does not establish the intended outcome “The VLAN map shows distinct Layer 2 domains and routed connectivity follows approved policy.” for the fictional Harborline Clinic case.
C:That result is evidence for a separate corrective action, “Record the exact model, LED name, color and blink pattern and interpret it using the model's documented table.”. It does not establish the intended outcome “The VLAN map shows distinct Layer 2 domains and routed connectivity follows approved policy.” for the fictional Harborline Clinic case.
Question 652
A change reviewer considers: At the fictional Harborline Clinic while assessing a controlled network fault, the team observes: Two PCs connected to one physical switch are in separate access VLANs and cannot talk without routing, but the help desk assumes all switch ports share one broadcast domain. During “Verify port VLAN membership and provide an authorized inter-VLAN routing path if communication is required.”, which precaution MOST specifically prevents a related risk?
- Do not improvise extra Ethernet loops just to create apparent redundancy.
- Do not infer a port's VLAN role solely from the patch cable's color.
- Do not bridge separate VLANs accidentally just to bypass a routing design requirement.
- Do not invent an unapproved alternate gateway IP on endpoints during an outage.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Verify port VLAN membership and provide an authorized inter-VLAN routing path if communication is required.” at the fictional Harborline Clinic. The required protection is “Do not bridge separate VLANs accidentally just to bypass a routing design requirement.”; success still requires “The VLAN map shows distinct Layer 2 domains and routed connectivity follows approved policy.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A field engineer provides a port-to-port cable schedule for a small three-switch network, but the technician connects each switch to every other switch without checking loop control. The principal adjacent risk here is controlled by “Do not bridge separate VLANs accidentally just to bypass a routing design requirement.”.
B:This caution is appropriate for a separate failure pattern: A topology shows a printer on a user access port and a distribution trunk between switches; the worker cables the printer into the inter-switch trunk's far end. The principal adjacent risk here is controlled by “Do not bridge separate VLANs accidentally just to bypass a routing design requirement.”.
D:This caution is appropriate for a separate failure pattern: A network has a redundant router and a failed primary gateway but the host points to a single unavailable default gateway IP. The principal adjacent risk here is controlled by “Do not bridge separate VLANs accidentally just to bypass a routing design requirement.”.
Question 653
During entry-level network support, consider: At the fictional Crescent Community Center after a site connectivity report, the team observes: A switch-to-switch uplink must carry several VLANs but one port is configured as a single access VLAN. Which action MOST directly resolves the reported issue?
- Validate the approved gateway availability mechanism and host default-gateway address.
- Configure and verify the supported VLAN trunk on the designated uplink.
- Install an approved SFP transceiver matching the cable and link speed.
- Repatch the AP cable to the documented approved PoE-capable access port.
Explanation
Correct Answer
B:Correct. In the fictional Crescent Community Center case, A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link. The specified corrective action, “Configure and verify the supported VLAN trunk on the designated uplink.”, directly targets that condition. Evidence of resolution: The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.
Incorrect Answers
A:That action addresses a different network issue: A network has a redundant router and a failed primary gateway but the host points to a single unavailable default gateway IP. The present fictional Crescent Community Center finding instead needs “Configure and verify the supported VLAN trunk on the designated uplink.”, verified by “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.”.
C:That action addresses a different network issue: A switch has a removable SFP slot and a trainee tries to plug an RJ-45 patch cord directly into the empty metal cage. The present fictional Crescent Community Center finding instead needs “Configure and verify the supported VLAN trunk on the designated uplink.”, verified by “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.”.
D:That action addresses a different network issue: A PoE access point is shown on port Gi1/0/12 but the technician patches it into a non-PoE port and it stays dark. The present fictional Crescent Community Center finding instead needs “Configure and verify the supported VLAN trunk on the designated uplink.”, verified by “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.”.
Question 654
The local support team reports: At the fictional Crescent Community Center after a site connectivity report, the team observes: A switch-to-switch uplink must carry several VLANs but one port is configured as a single access VLAN. What is the MOST specific underlying cause?
- A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link.
- A console port provides device-management terminal access rather than ordinary switched Ethernet service.
- A properly configured Layer 3 switch can route between VLAN interfaces, unlike a Layer 2-only switch.
- IPv4 routers decrement TTL to help prevent packets from looping indefinitely.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Crescent Community Center: A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link. The corresponding remedy is “Configure and verify the supported VLAN trunk on the designated uplink.”. Confirmation: The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.
Incorrect Answers
B:That cause belongs to a different case: A technician connects an Ethernet patch lead to the blue-labelled console jack and wonders why no data-link address appears on the switch uplink. The observed fictional Crescent Community Center condition is specifically explained by “A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link.”.
C:That cause belongs to a different case: A technician says a Layer 3 switch can only learn MAC addresses and is incapable of routing between configured VLAN interfaces. The observed fictional Crescent Community Center condition is specifically explained by “A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link.”.
D:That cause belongs to a different case: A technician sees that packet TTL decreases at a routed hop and calls it corruption that must be repaired by disabling routing. The observed fictional Crescent Community Center condition is specifically explained by “A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link.”.
Question 655
The technician must verify the following scenario: At the fictional Crescent Community Center after a site connectivity report, the team observes: A switch-to-switch uplink must carry several VLANs but one port is configured as a single access VLAN. The approved corrective action is: “Configure and verify the supported VLAN trunk on the designated uplink.” Which result BEST demonstrates success?
- Port activity indications correlate with test traffic while interface error counters remain acceptable.
- A trace verifies the exact physical endpoints required by the network diagram.
- The terminal emulator shows a local device prompt without depending on a routed IP session.
- The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Configure and verify the supported VLAN trunk on the designated uplink.” at the fictional Crescent Community Center. It demonstrates correction of the original cause: A trunk is used to carry multiple VLANs over an appropriately configured inter-switch link.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Identify the specific port's link/activity LED behavior in its documented status guide.”. It does not establish the intended outcome “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.” for the fictional Crescent Community Center case.
B:That result is evidence for a separate corrective action, “Use the cable labels and tester to reconnect panel 24 to switch B port 7.”. It does not establish the intended outcome “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.” for the fictional Crescent Community Center case.
C:That result is evidence for a separate corrective action, “Choose the correct physical COM or USB serial adapter and attach it to the Cisco console interface.”. It does not establish the intended outcome “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.” for the fictional Crescent Community Center case.
Question 656
A change reviewer considers: At the fictional Crescent Community Center after a site connectivity report, the team observes: A switch-to-switch uplink must carry several VLANs but one port is configured as a single access VLAN. During “Configure and verify the supported VLAN trunk on the designated uplink.”, which precaution MOST specifically prevents a related risk?
- Do not assume a management Ethernet port is interchangeable with a data-plane access port.
- Do not conceal incorrect cabling with speculative IP or VLAN changes.
- Do not configure user endpoint ports as broad unrestricted trunks without a requirement.
- Do not bypass fiber-interface requirements with an unrelated copper connector.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Configure and verify the supported VLAN trunk on the designated uplink.” at the fictional Crescent Community Center. The required protection is “Do not configure user endpoint ports as broad unrestricted trunks without a requirement.”; success still requires “The allowed VLANs cross the uplink while end-device access ports remain assigned to one VLAN.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A device has both a dedicated management Ethernet jack and ordinary switched data ports, but an installer uses the management jack for end-user PC access. The principal adjacent risk here is controlled by “Do not configure user endpoint ports as broad unrestricted trunks without a requirement.”.
B:This caution is appropriate for a separate failure pattern: A diagram explicitly labels rack A panel 24 to switch B port 7, but the installer connects panel 23 and concludes that logical VLAN changes will repair the wrong patch. The principal adjacent risk here is controlled by “Do not configure user endpoint ports as broad unrestricted trunks without a requirement.”.
D:This caution is appropriate for a separate failure pattern: A fiber uplink terminates in an LC optical transceiver but the worker tries to use a telephone RJ-11 lead to connect the switches. The principal adjacent risk here is controlled by “Do not configure user endpoint ports as broad unrestricted trunks without a requirement.”.
Question 657
During entry-level network support, consider: At the fictional Willowbrook Campus during its network support shift, the team observes: A technician moves a workstation to a different port and the switch initially sends some traffic to its old location. Which action MOST directly resolves the reported issue?
- Check the host's subnet mask and local neighbor resolution for the directly connected target.
- Inspect the MAC address table and allow or trigger legitimate relearning after the move.
- Use the specified compatible fiber run and transceivers for the distribution uplink.
- Compare matching prefix lengths and use the 10.20.0.0/16 route for a destination such as 10.20.5.6.
Explanation
Correct Answer
B:Correct. In the fictional Willowbrook Campus case, MAC learning and aging or relearning govern how a switch updates host-to-port information. The specified corrective action, “Inspect the MAC address table and allow or trigger legitimate relearning after the move.”, directly targets that condition. Evidence of resolution: The host's MAC now maps to the new port and frames are delivered correctly.
Incorrect Answers
A:That action addresses a different network issue: A host sees another device on the same 192.168.7.0/24 segment and sends all packets to its gateway rather than using local neighbor resolution. The present fictional Willowbrook Campus finding instead needs “Inspect the MAC address table and allow or trigger legitimate relearning after the move.”, verified by “The host's MAC now maps to the new port and frames are delivered correctly.”.
C:That action addresses a different network issue: A diagram specifies a fiber link between two distribution switches but the installer uses a short twisted-pair patch cord to bridge the racks across a long cable tray. The present fictional Willowbrook Campus finding instead needs “Inspect the MAC address table and allow or trigger legitimate relearning after the move.”, verified by “The host's MAC now maps to the new port and frames are delivered correctly.”.
D:That action addresses a different network issue: A branch router has a specific route to 10.20.0.0/16 and a default route, but the trainee expects all 10.x.x.x traffic to use the default. The present fictional Willowbrook Campus finding instead needs “Inspect the MAC address table and allow or trigger legitimate relearning after the move.”, verified by “The host's MAC now maps to the new port and frames are delivered correctly.”.
Question 658
The local support team reports: At the fictional Willowbrook Campus during its network support shift, the team observes: A technician moves a workstation to a different port and the switch initially sends some traffic to its old location. What is the MOST specific underlying cause?
- MAC learning and aging or relearning govern how a switch updates host-to-port information.
- Port function is determined by actual hardware labels and configuration, not arbitrary patch-cable colors.
- Longest-prefix matching selects a specific matching route over a less-specific default route.
- Redundant topology requires distinct documented ports and correct optical terminations on each link.
Explanation
Correct Answer
A:Correct. This mechanism fits the observed network symptom at the fictional Willowbrook Campus: MAC learning and aging or relearning govern how a switch updates host-to-port information. The corresponding remedy is “Inspect the MAC address table and allow or trigger legitimate relearning after the move.”. Confirmation: The host's MAC now maps to the new port and frames are delivered correctly.
Incorrect Answers
B:That cause belongs to a different case: A network team labels the RJ-45 connection on a firewall as a console because its cable is blue, while the interface status shows routed Ethernet traffic. The observed fictional Willowbrook Campus condition is specifically explained by “MAC learning and aging or relearning govern how a switch updates host-to-port information.”.
C:That cause belongs to a different case: A branch router has a specific route to 10.20.0.0/16 and a default route, but the trainee expects all 10.x.x.x traffic to use the default. The observed fictional Willowbrook Campus condition is specifically explained by “MAC learning and aging or relearning govern how a switch updates host-to-port information.”.
D:That cause belongs to a different case: A rack elevation places two redundant uplinks on separate switch ports but the installer connects both strands to the same unsupported transceiver and records two working paths. The observed fictional Willowbrook Campus condition is specifically explained by “MAC learning and aging or relearning govern how a switch updates host-to-port information.”.
Question 659
The technician must verify the following scenario: At the fictional Willowbrook Campus during its network support shift, the team observes: A technician moves a workstation to a different port and the switch initially sends some traffic to its old location. The approved corrective action is: “Inspect the MAC address table and allow or trigger legitimate relearning after the move.” Which result BEST demonstrates success?
- The endpoint negotiates Ethernet on the data port while the console remains available for CLI sessions.
- The SFP is recognized and the correct patch lead brings the uplink into link-up state.
- The physical link establishes and the port LED follows the device's documented link indication.
- The host's MAC now maps to the new port and frames are delivered correctly.
Explanation
Correct Answer
D:Correct. This is the required observable acceptance evidence for “Inspect the MAC address table and allow or trigger legitimate relearning after the move.” at the fictional Willowbrook Campus. It demonstrates correction of the original cause: MAC learning and aging or relearning govern how a switch updates host-to-port information.
Incorrect Answers
A:That result is evidence for a separate corrective action, “Identify and use the designated Ethernet data port for network traffic; reserve console for local administration.”. It does not establish the intended outcome “The host's MAC now maps to the new port and frames are delivered correctly.” for the fictional Willowbrook Campus case.
B:That result is evidence for a separate corrective action, “Install an approved SFP transceiver matching the cable and link speed.”. It does not establish the intended outcome “The host's MAC now maps to the new port and frames are delivered correctly.” for the fictional Willowbrook Campus case.
C:That result is evidence for a separate corrective action, “Verify cable seating, peer port status and the interface's configured state.”. It does not establish the intended outcome “The host's MAC now maps to the new port and frames are delivered correctly.” for the fictional Willowbrook Campus case.
Question 660
A change reviewer considers: At the fictional Willowbrook Campus during its network support shift, the team observes: A technician moves a workstation to a different port and the switch initially sends some traffic to its old location. During “Inspect the MAC address table and allow or trigger legitimate relearning after the move.”, which precaution MOST specifically prevents a related risk?
- Do not invent an unapproved alternate gateway IP on endpoints during an outage.
- Do not troubleshoot remote application sockets before restoring a failed gateway uplink.
- Do not hard-code stale MAC-to-port entries to hide a moving endpoint.
- Do not assume creating a local SVI automatically installs routes to every remote site.
Explanation
Correct Answer
C:Correct. This precaution prevents a second fault while applying “Inspect the MAC address table and allow or trigger legitimate relearning after the move.” at the fictional Willowbrook Campus. The required protection is “Do not hard-code stale MAC-to-port entries to hide a moving endpoint.”; success still requires “The host's MAC now maps to the new port and frames are delivered correctly.”.
Incorrect Answers
A:This caution is appropriate for a separate failure pattern: A network has a redundant router and a failed primary gateway but the host points to a single unavailable default gateway IP. The principal adjacent risk here is controlled by “Do not hard-code stale MAC-to-port entries to hide a moving endpoint.”.
B:This caution is appropriate for a separate failure pattern: A PC sends traffic to a remote server but the gateway's Ethernet interface is down and the technician tries to edit only the server's application port. The principal adjacent risk here is controlled by “Do not hard-code stale MAC-to-port entries to hide a moving endpoint.”.
D:This caution is appropriate for a separate failure pattern: A VLAN interface 10.3.5.1/24 is intended to route client traffic but lacks any configuration for reaching 10.7.0.0/16 on another router. The principal adjacent risk here is controlled by “Do not hard-code stale MAC-to-port entries to hide a moving endpoint.”.