CompTIA Network+ N10-009 Switching Routing Addressing And Network Service Troubleshooting Practice Test

 

Objective 5.3 • 35 original questions

This CompTIA Network+ N10-009 practice test focuses on network-service troubleshooting. All questions are original ExamSnap scenarios aligned to the current N10-009 blueprint; they are not copied from CompTIA exam content. Use the complete N10-009 collection for broader practice across all five domains. For broader exam preparation, review the CompTIA Network+ N10-009 Exam Dumps page.

Instructions: Select the best answer for each question. Review the explanation after answering; each distractor includes a reason it is not the best choice for that scenario.

Question 1

At Litware Manufacturing, a systems administrator is reviewing a network change. The requirement is to diagnose a switched network with broadcast storms and rapidly changing MAC-table entries. Which option is the best fit? The decision applies to a branch-office rollout.

1. Blocking ACL
2. Duplicate IP address
3. Wrong STP root bridge
4. Bad default route
5. STP loop

Correct answer: E

Why: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. This directly satisfies the requirement: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Option review:

A: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

B: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

C: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

D: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

E: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. This directly satisfies the requirement: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Learning point: Use STP loop when the key requirement is to diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Question 2

A ticket at Woodgrove Bank says the team must diagnose a campus where traffic takes suboptimal paths because the wrong switch became root. Which technology or concept most directly addresses this requirement? The decision applies to a campus refresh.

1. STP port role/state
2. Incorrect IP address
3. Wrong STP root bridge
4. Incorrect VLAN assignment
5. Bad default route

Correct answer: C

Why: An unintended root can create inefficient forwarding paths even if STP prevents loops. This directly satisfies the requirement: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Option review:

A: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

B: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

C: An unintended root can create inefficient forwarding paths even if STP prevents loops. This directly satisfies the requirement: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

D: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

E: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Learning point: Use Wrong STP root bridge when the key requirement is to diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Question 3

During a design meeting at Blue Yonder Airlines, the junior network administrator needs to diagnose why a redundant switch link is not forwarding user traffic. What should be selected? The decision applies to a data-center segment.

1. DHCP pool exhaustion
2. STP port role/state
3. Missing route
4. Incorrect subnet mask
5. Bad default route

Correct answer: B

Why: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. This directly satisfies the requirement: diagnose why a redundant switch link is not forwarding user traffic.

Option review:

A: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

B: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. This directly satisfies the requirement: diagnose why a redundant switch link is not forwarding user traffic.

C: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

D: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

E: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

Learning point: Use STP port role/state when the key requirement is to diagnose why a redundant switch link is not forwarding user traffic.

Question 4

Contoso Health is updating its network standard. Which option best meets the need to diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers? The decision applies to a remote-site migration.

1. Missing route
2. Incorrect VLAN assignment
3. Bad default route
4. STP loop
5. Incorrect subnet mask

Correct answer: B

Why: An access port in the wrong VLAN places the host in the wrong broadcast domain. This directly satisfies the requirement: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

B: An access port in the wrong VLAN places the host in the wrong broadcast domain. This directly satisfies the requirement: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

C: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

D: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

E: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Learning point: Use Incorrect VLAN assignment when the key requirement is to diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Question 5

A field technician at Litware Manufacturing is validating a proposed solution. The design must diagnose traffic that has a valid route but is consistently denied at a network boundary. Which answer is most appropriate? The decision applies to a operations lab.

1. Missing route
2. STP loop
3. Duplicate IP address
4. STP port role/state
5. Blocking ACL

Correct answer: E

Why: An access control list can deny otherwise correctly routed traffic. This directly satisfies the requirement: diagnose traffic that has a valid route but is consistently denied at a network boundary.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

B: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

C: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

D: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

E: An access control list can deny otherwise correctly routed traffic. This directly satisfies the requirement: diagnose traffic that has a valid route but is consistently denied at a network boundary.

Learning point: Use Blocking ACL when the key requirement is to diagnose traffic that has a valid route but is consistently denied at a network boundary.

Question 6

For a new deployment at Woodgrove Bank, the networking team wants to diagnose reachability failure where a router has no route for the remote network. Which choice most directly satisfies the goal? The decision applies to a production maintenance window.

1. STP loop
2. Incorrect subnet mask
3. Missing route
4. STP port role/state
5. Duplicate IP address

Correct answer: C

Why: If no specific or default route matches a destination, the router cannot forward the packet. This directly satisfies the requirement: diagnose reachability failure where a router has no route for the remote network.

Option review:

A: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

B: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

C: If no specific or default route matches a destination, the router cannot forward the packet. This directly satisfies the requirement: diagnose reachability failure where a router has no route for the remote network.

D: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

E: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

Learning point: Use Missing route when the key requirement is to diagnose reachability failure where a router has no route for the remote network.

Question 7

At Blue Yonder Airlines, a systems administrator is reviewing a network change. The requirement is to diagnose widespread internet failure caused by an incorrect router default route. Which option is the best fit? The decision applies to a new floor deployment.

1. Missing route
2. Incorrect VLAN assignment
3. Bad default route
4. STP port role/state
5. Incorrect default gateway

Correct answer: C

Why: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. This directly satisfies the requirement: diagnose widespread internet failure caused by an incorrect router default route.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

B: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

C: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. This directly satisfies the requirement: diagnose widespread internet failure caused by an incorrect router default route.

D: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

E: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

Learning point: Use Bad default route when the key requirement is to diagnose widespread internet failure caused by an incorrect router default route.

Question 8

A ticket at Contoso Health says the team must diagnose new clients failing DHCP while existing leased clients continue working. Which technology or concept most directly addresses this requirement? The decision applies to a service-recovery review.

1. Bad default route
2. Wrong STP root bridge
3. Incorrect IP address
4. DHCP pool exhaustion
5. Incorrect VLAN assignment

Correct answer: D

Why: No free addresses remain in the scope, so new clients cannot obtain leases. This directly satisfies the requirement: diagnose new clients failing DHCP while existing leased clients continue working.

Option review:

A: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

B: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

C: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

D: No free addresses remain in the scope, so new clients cannot obtain leases. This directly satisfies the requirement: diagnose new clients failing DHCP while existing leased clients continue working.

E: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

Learning point: Use DHCP pool exhaustion when the key requirement is to diagnose new clients failing DHCP while existing leased clients continue working.

Question 9

During a design meeting at Litware Manufacturing, the junior network administrator needs to diagnose a client that reaches local peers but not off-subnet destinations. What should be selected? The decision applies to a branch-office rollout.

1. Wrong STP root bridge
2. Incorrect default gateway
3. Duplicate IP address
4. STP port role/state
5. Incorrect VLAN assignment

Correct answer: B

Why: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. This directly satisfies the requirement: diagnose a client that reaches local peers but not off-subnet destinations.

Option review:

A: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

B: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. This directly satisfies the requirement: diagnose a client that reaches local peers but not off-subnet destinations.

C: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

D: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

E: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

Learning point: Use Incorrect default gateway when the key requirement is to diagnose a client that reaches local peers but not off-subnet destinations.

Question 10

Woodgrove Bank is updating its network standard. Which option best meets the need to diagnose a client whose address does not belong to the VLAN’s assigned subnet? The decision applies to a campus refresh.

1. Incorrect IP address
2. Incorrect subnet mask
3. Incorrect default gateway
4. Wrong STP root bridge
5. Missing route

Correct answer: A

Why: A host configured for the wrong subnet may be unable to reach intended local or remote resources. This directly satisfies the requirement: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Option review:

A: A host configured for the wrong subnet may be unable to reach intended local or remote resources. This directly satisfies the requirement: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

B: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

C: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

D: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

E: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Learning point: Use Incorrect IP address when the key requirement is to diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Question 11

A field technician at Blue Yonder Airlines is validating a proposed solution. The design must diagnose intermittent access accompanied by duplicate-address warnings. Which answer is most appropriate? The decision applies to a data-center segment.

1. Bad default route
2. Incorrect IP address
3. Incorrect default gateway
4. DHCP pool exhaustion
5. Duplicate IP address

Correct answer: E

Why: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. This directly satisfies the requirement: diagnose intermittent access accompanied by duplicate-address warnings.

Option review:

A: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

B: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

C: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

D: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

E: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. This directly satisfies the requirement: diagnose intermittent access accompanied by duplicate-address warnings.

Learning point: Use Duplicate IP address when the key requirement is to diagnose intermittent access accompanied by duplicate-address warnings.

Question 12

For a new deployment at Contoso Health, the networking team wants to diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask. Which choice most directly satisfies the goal? The decision applies to a remote-site migration.

1. Incorrect subnet mask
2. Wrong STP root bridge
3. Blocking ACL
4. Incorrect VLAN assignment
5. Incorrect default gateway

Correct answer: A

Why: A wrong mask makes a host incorrectly classify destinations as local or remote. This directly satisfies the requirement: diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

Option review:

A: A wrong mask makes a host incorrectly classify destinations as local or remote. This directly satisfies the requirement: diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

B: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

C: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

D: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

E: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

Learning point: Use Incorrect subnet mask when the key requirement is to diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

Question 13

During a service-recovery review, Litware Manufacturing is comparing several networking concepts. Which option is accurately characterized by this statement: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion.

1. Wrong STP root bridge
2. DHCP pool exhaustion
3. Bad default route
4. Incorrect subnet mask
5. STP loop

Correct answer: E

Why: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. This directly satisfies the requirement: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion..

Option review:

A: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion..

B: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion..

C: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion..

D: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion..

E: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. This directly satisfies the requirement: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion..

Learning point: Use STP loop when the key requirement is to diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Question 14

During a branch-office rollout, Woodgrove Bank is comparing several networking concepts. Which option is accurately characterized by this statement: An unintended root can create inefficient forwarding paths even if STP prevents loops.

1. Missing route
2. Bad default route
3. Incorrect IP address
4. Wrong STP root bridge
5. Incorrect VLAN assignment

Correct answer: D

Why: An unintended root can create inefficient forwarding paths even if STP prevents loops. This directly satisfies the requirement: An unintended root can create inefficient forwarding paths even if STP prevents loops..

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: An unintended root can create inefficient forwarding paths even if STP prevents loops..

B: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: An unintended root can create inefficient forwarding paths even if STP prevents loops..

C: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: An unintended root can create inefficient forwarding paths even if STP prevents loops..

D: An unintended root can create inefficient forwarding paths even if STP prevents loops. This directly satisfies the requirement: An unintended root can create inefficient forwarding paths even if STP prevents loops..

E: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: An unintended root can create inefficient forwarding paths even if STP prevents loops..

Learning point: Use Wrong STP root bridge when the key requirement is to diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Question 15

During a campus refresh, Blue Yonder Airlines is comparing several networking concepts. Which option is accurately characterized by this statement: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop.

1. Bad default route
2. Incorrect IP address
3. STP port role/state
4. STP loop
5. Missing route

Correct answer: C

Why: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. This directly satisfies the requirement: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop..

Option review:

A: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop..

B: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop..

C: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. This directly satisfies the requirement: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop..

D: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop..

E: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop..

Learning point: Use STP port role/state when the key requirement is to diagnose why a redundant switch link is not forwarding user traffic.

Question 16

During a data-center segment, Contoso Health is comparing several networking concepts. Which option is accurately characterized by this statement: An access port in the wrong VLAN places the host in the wrong broadcast domain.

1. STP loop
2. Incorrect subnet mask
3. Incorrect VLAN assignment
4. DHCP pool exhaustion
5. Wrong STP root bridge

Correct answer: C

Why: An access port in the wrong VLAN places the host in the wrong broadcast domain. This directly satisfies the requirement: An access port in the wrong VLAN places the host in the wrong broadcast domain..

Option review:

A: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: An access port in the wrong VLAN places the host in the wrong broadcast domain..

B: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: An access port in the wrong VLAN places the host in the wrong broadcast domain..

C: An access port in the wrong VLAN places the host in the wrong broadcast domain. This directly satisfies the requirement: An access port in the wrong VLAN places the host in the wrong broadcast domain..

D: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: An access port in the wrong VLAN places the host in the wrong broadcast domain..

E: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: An access port in the wrong VLAN places the host in the wrong broadcast domain..

Learning point: Use Incorrect VLAN assignment when the key requirement is to diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Question 17

During a remote-site migration, Litware Manufacturing is comparing several networking concepts. Which option is accurately characterized by this statement: An access control list can deny otherwise correctly routed traffic.

1. STP loop
2. DHCP pool exhaustion
3. Wrong STP root bridge
4. Blocking ACL
5. Bad default route

Correct answer: D

Why: An access control list can deny otherwise correctly routed traffic. This directly satisfies the requirement: An access control list can deny otherwise correctly routed traffic..

Option review:

A: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: An access control list can deny otherwise correctly routed traffic..

B: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: An access control list can deny otherwise correctly routed traffic..

C: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: An access control list can deny otherwise correctly routed traffic..

D: An access control list can deny otherwise correctly routed traffic. This directly satisfies the requirement: An access control list can deny otherwise correctly routed traffic..

E: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: An access control list can deny otherwise correctly routed traffic..

Learning point: Use Blocking ACL when the key requirement is to diagnose traffic that has a valid route but is consistently denied at a network boundary.

Question 18

During a operations lab, Woodgrove Bank is comparing several networking concepts. Which option is accurately characterized by this statement: If no specific or default route matches a destination, the router cannot forward the packet.

1. Incorrect default gateway
2. Duplicate IP address
3. Incorrect VLAN assignment
4. Missing route
5. Incorrect subnet mask

Correct answer: D

Why: If no specific or default route matches a destination, the router cannot forward the packet. This directly satisfies the requirement: If no specific or default route matches a destination, the router cannot forward the packet..

Option review:

A: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: If no specific or default route matches a destination, the router cannot forward the packet..

B: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: If no specific or default route matches a destination, the router cannot forward the packet..

C: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: If no specific or default route matches a destination, the router cannot forward the packet..

D: If no specific or default route matches a destination, the router cannot forward the packet. This directly satisfies the requirement: If no specific or default route matches a destination, the router cannot forward the packet..

E: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: If no specific or default route matches a destination, the router cannot forward the packet..

Learning point: Use Missing route when the key requirement is to diagnose reachability failure where a router has no route for the remote network.

Question 19

During a production maintenance window, Blue Yonder Airlines is comparing several networking concepts. Which option is accurately characterized by this statement: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way.

1. Blocking ACL
2. Wrong STP root bridge
3. Incorrect subnet mask
4. Bad default route
5. Incorrect IP address

Correct answer: D

Why: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. This directly satisfies the requirement: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way..

Option review:

A: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way..

B: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way..

C: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way..

D: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. This directly satisfies the requirement: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way..

E: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way..

Learning point: Use Bad default route when the key requirement is to diagnose widespread internet failure caused by an incorrect router default route.

Question 20

During a new floor deployment, Contoso Health is comparing several networking concepts. Which option is accurately characterized by this statement: No free addresses remain in the scope, so new clients cannot obtain leases.

1. Incorrect IP address
2. Wrong STP root bridge
3. Bad default route
4. Missing route
5. DHCP pool exhaustion

Correct answer: E

Why: No free addresses remain in the scope, so new clients cannot obtain leases. This directly satisfies the requirement: No free addresses remain in the scope, so new clients cannot obtain leases..

Option review:

A: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: No free addresses remain in the scope, so new clients cannot obtain leases..

B: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: No free addresses remain in the scope, so new clients cannot obtain leases..

C: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: No free addresses remain in the scope, so new clients cannot obtain leases..

D: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: No free addresses remain in the scope, so new clients cannot obtain leases..

E: No free addresses remain in the scope, so new clients cannot obtain leases. This directly satisfies the requirement: No free addresses remain in the scope, so new clients cannot obtain leases..

Learning point: Use DHCP pool exhaustion when the key requirement is to diagnose new clients failing DHCP while existing leased clients continue working.

Question 21

During a service-recovery review, Litware Manufacturing is comparing several networking concepts. Which option is accurately characterized by this statement: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong.

1. Blocking ACL
2. Incorrect default gateway
3. Missing route
4. Duplicate IP address
5. Incorrect VLAN assignment

Correct answer: B

Why: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. This directly satisfies the requirement: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong..

Option review:

A: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong..

B: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. This directly satisfies the requirement: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong..

C: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong..

D: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong..

E: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong..

Learning point: Use Incorrect default gateway when the key requirement is to diagnose a client that reaches local peers but not off-subnet destinations.

Question 22

During a branch-office rollout, Woodgrove Bank is comparing several networking concepts. Which option is accurately characterized by this statement: A host configured for the wrong subnet may be unable to reach intended local or remote resources.

1. Missing route
2. STP port role/state
3. STP loop
4. Duplicate IP address
5. Incorrect IP address

Correct answer: E

Why: A host configured for the wrong subnet may be unable to reach intended local or remote resources. This directly satisfies the requirement: A host configured for the wrong subnet may be unable to reach intended local or remote resources..

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: A host configured for the wrong subnet may be unable to reach intended local or remote resources..

B: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: A host configured for the wrong subnet may be unable to reach intended local or remote resources..

C: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: A host configured for the wrong subnet may be unable to reach intended local or remote resources..

D: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: A host configured for the wrong subnet may be unable to reach intended local or remote resources..

E: A host configured for the wrong subnet may be unable to reach intended local or remote resources. This directly satisfies the requirement: A host configured for the wrong subnet may be unable to reach intended local or remote resources..

Learning point: Use Incorrect IP address when the key requirement is to diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Question 23

During a campus refresh, Blue Yonder Airlines is comparing several networking concepts. Which option is accurately characterized by this statement: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability.

1. STP loop
2. Bad default route
3. Blocking ACL
4. Duplicate IP address
5. Missing route

Correct answer: D

Why: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. This directly satisfies the requirement: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability..

Option review:

A: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability..

B: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability..

C: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability..

D: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. This directly satisfies the requirement: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability..

E: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability..

Learning point: Use Duplicate IP address when the key requirement is to diagnose intermittent access accompanied by duplicate-address warnings.

Question 24

During a data-center segment, Contoso Health is comparing several networking concepts. Which option is accurately characterized by this statement: A wrong mask makes a host incorrectly classify destinations as local or remote.

1. Blocking ACL
2. Incorrect subnet mask
3. Incorrect default gateway
4. Incorrect IP address
5. Wrong STP root bridge

Correct answer: B

Why: A wrong mask makes a host incorrectly classify destinations as local or remote. This directly satisfies the requirement: A wrong mask makes a host incorrectly classify destinations as local or remote..

Option review:

A: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: A wrong mask makes a host incorrectly classify destinations as local or remote..

B: A wrong mask makes a host incorrectly classify destinations as local or remote. This directly satisfies the requirement: A wrong mask makes a host incorrectly classify destinations as local or remote..

C: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: A wrong mask makes a host incorrectly classify destinations as local or remote..

D: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: A wrong mask makes a host incorrectly classify destinations as local or remote..

E: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: A wrong mask makes a host incorrectly classify destinations as local or remote..

Learning point: Use Incorrect subnet mask when the key requirement is to diagnose selective reachability because the client has the correct IP but an incorrect prefix/mask.

Question 25

A systems administrator at Litware Manufacturing is troubleshooting a new floor deployment. The team has isolated the key need as follows: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries. Which concept should be applied or investigated first?

1. Missing route
2. Blocking ACL
3. Incorrect default gateway
4. STP port role/state
5. STP loop

Correct answer: E

Why: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. This directly satisfies the requirement: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

B: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

C: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

D: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. However, it does not most directly satisfy the requirement in this scenario: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

E: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. This directly satisfies the requirement: diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Learning point: Use STP loop when the key requirement is to diagnose a switched network with broadcast storms and rapidly changing MAC-table entries.

Question 26

A NOC analyst at Woodgrove Bank is troubleshooting a service-recovery review. The team has isolated the key need as follows: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root. Which concept should be applied or investigated first?

1. Blocking ACL
2. Bad default route
3. Wrong STP root bridge
4. Missing route
5. STP loop

Correct answer: C

Why: An unintended root can create inefficient forwarding paths even if STP prevents loops. This directly satisfies the requirement: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Option review:

A: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

B: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

C: An unintended root can create inefficient forwarding paths even if STP prevents loops. This directly satisfies the requirement: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

D: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

E: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Learning point: Use Wrong STP root bridge when the key requirement is to diagnose a campus where traffic takes suboptimal paths because the wrong switch became root.

Question 27

A junior network administrator at Blue Yonder Airlines is troubleshooting a branch-office rollout. The team has isolated the key need as follows: diagnose why a redundant switch link is not forwarding user traffic. Which concept should be applied or investigated first?

1. Duplicate IP address
2. Incorrect default gateway
3. STP port role/state
4. STP loop
5. Missing route

Correct answer: C

Why: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. This directly satisfies the requirement: diagnose why a redundant switch link is not forwarding user traffic.

Option review:

A: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

B: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

C: Incorrect or unexpected STP roles/states can block traffic on a link or expose a loop. This directly satisfies the requirement: diagnose why a redundant switch link is not forwarding user traffic.

D: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

E: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose why a redundant switch link is not forwarding user traffic.

Learning point: Use STP port role/state when the key requirement is to diagnose why a redundant switch link is not forwarding user traffic.

Question 28

A network technician at Contoso Health is troubleshooting a campus refresh. The team has isolated the key need as follows: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers. Which concept should be applied or investigated first?

1. Duplicate IP address
2. DHCP pool exhaustion
3. Incorrect default gateway
4. Incorrect subnet mask
5. Incorrect VLAN assignment

Correct answer: E

Why: An access port in the wrong VLAN places the host in the wrong broadcast domain. This directly satisfies the requirement: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Option review:

A: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

B: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

C: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

D: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

E: An access port in the wrong VLAN places the host in the wrong broadcast domain. This directly satisfies the requirement: diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Learning point: Use Incorrect VLAN assignment when the key requirement is to diagnose a user who can link to the switch but reaches the wrong subnet or cannot reach expected local peers.

Question 29

A field technician at Litware Manufacturing is troubleshooting a data-center segment. The team has isolated the key need as follows: diagnose traffic that has a valid route but is consistently denied at a network boundary. Which concept should be applied or investigated first?

1. Missing route
2. Blocking ACL
3. Wrong STP root bridge
4. Incorrect default gateway
5. Duplicate IP address

Correct answer: B

Why: An access control list can deny otherwise correctly routed traffic. This directly satisfies the requirement: diagnose traffic that has a valid route but is consistently denied at a network boundary.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

B: An access control list can deny otherwise correctly routed traffic. This directly satisfies the requirement: diagnose traffic that has a valid route but is consistently denied at a network boundary.

C: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

D: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

E: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose traffic that has a valid route but is consistently denied at a network boundary.

Learning point: Use Blocking ACL when the key requirement is to diagnose traffic that has a valid route but is consistently denied at a network boundary.

Question 30

A network support specialist at Woodgrove Bank is troubleshooting a remote-site migration. The team has isolated the key need as follows: diagnose reachability failure where a router has no route for the remote network. Which concept should be applied or investigated first?

1. Missing route
2. Bad default route
3. DHCP pool exhaustion
4. STP loop
5. Wrong STP root bridge

Correct answer: A

Why: If no specific or default route matches a destination, the router cannot forward the packet. This directly satisfies the requirement: diagnose reachability failure where a router has no route for the remote network.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. This directly satisfies the requirement: diagnose reachability failure where a router has no route for the remote network.

B: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

C: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

D: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

E: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose reachability failure where a router has no route for the remote network.

Learning point: Use Missing route when the key requirement is to diagnose reachability failure where a router has no route for the remote network.

Question 31

A systems administrator at Blue Yonder Airlines is troubleshooting a operations lab. The team has isolated the key need as follows: diagnose widespread internet failure caused by an incorrect router default route. Which concept should be applied or investigated first?

1. Incorrect default gateway
2. STP loop
3. Bad default route
4. Incorrect IP address
5. Blocking ACL

Correct answer: C

Why: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. This directly satisfies the requirement: diagnose widespread internet failure caused by an incorrect router default route.

Option review:

A: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

B: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

C: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. This directly satisfies the requirement: diagnose widespread internet failure caused by an incorrect router default route.

D: A host configured for the wrong subnet may be unable to reach intended local or remote resources. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

E: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: diagnose widespread internet failure caused by an incorrect router default route.

Learning point: Use Bad default route when the key requirement is to diagnose widespread internet failure caused by an incorrect router default route.

Question 32

A NOC analyst at Contoso Health is troubleshooting a production maintenance window. The team has isolated the key need as follows: diagnose new clients failing DHCP while existing leased clients continue working. Which concept should be applied or investigated first?

1. Incorrect subnet mask
2. STP loop
3. DHCP pool exhaustion
4. Missing route
5. Bad default route

Correct answer: C

Why: No free addresses remain in the scope, so new clients cannot obtain leases. This directly satisfies the requirement: diagnose new clients failing DHCP while existing leased clients continue working.

Option review:

A: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

B: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

C: No free addresses remain in the scope, so new clients cannot obtain leases. This directly satisfies the requirement: diagnose new clients failing DHCP while existing leased clients continue working.

D: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

E: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose new clients failing DHCP while existing leased clients continue working.

Learning point: Use DHCP pool exhaustion when the key requirement is to diagnose new clients failing DHCP while existing leased clients continue working.

Question 33

A junior network administrator at Litware Manufacturing is troubleshooting a new floor deployment. The team has isolated the key need as follows: diagnose a client that reaches local peers but not off-subnet destinations. Which concept should be applied or investigated first?

1. STP loop
2. DHCP pool exhaustion
3. Missing route
4. Incorrect VLAN assignment
5. Incorrect default gateway

Correct answer: E

Why: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. This directly satisfies the requirement: diagnose a client that reaches local peers but not off-subnet destinations.

Option review:

A: A Layer 2 forwarding loop causes broadcast storms, MAC-table instability, and severe congestion. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

B: No free addresses remain in the scope, so new clients cannot obtain leases. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

C: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

D: An access port in the wrong VLAN places the host in the wrong broadcast domain. However, it does not most directly satisfy the requirement in this scenario: diagnose a client that reaches local peers but not off-subnet destinations.

E: The host can reach its local subnet but cannot reach remote networks when its gateway is wrong. This directly satisfies the requirement: diagnose a client that reaches local peers but not off-subnet destinations.

Learning point: Use Incorrect default gateway when the key requirement is to diagnose a client that reaches local peers but not off-subnet destinations.

Question 34

A network technician at Woodgrove Bank is troubleshooting a service-recovery review. The team has isolated the key need as follows: diagnose a client whose address does not belong to the VLAN’s assigned subnet. Which concept should be applied or investigated first?

1. Duplicate IP address
2. Blocking ACL
3. Incorrect IP address
4. Incorrect subnet mask
5. Wrong STP root bridge

Correct answer: C

Why: A host configured for the wrong subnet may be unable to reach intended local or remote resources. This directly satisfies the requirement: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Option review:

A: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

B: An access control list can deny otherwise correctly routed traffic. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

C: A host configured for the wrong subnet may be unable to reach intended local or remote resources. This directly satisfies the requirement: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

D: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

E: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Learning point: Use Incorrect IP address when the key requirement is to diagnose a client whose address does not belong to the VLAN’s assigned subnet.

Question 35

A field technician at Blue Yonder Airlines is troubleshooting a branch-office rollout. The team has isolated the key need as follows: diagnose intermittent access accompanied by duplicate-address warnings. Which concept should be applied or investigated first?

1. Missing route
2. Incorrect subnet mask
3. Wrong STP root bridge
4. Duplicate IP address
5. Bad default route

Correct answer: D

Why: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. This directly satisfies the requirement: diagnose intermittent access accompanied by duplicate-address warnings.

Option review:

A: If no specific or default route matches a destination, the router cannot forward the packet. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

B: A wrong mask makes a host incorrectly classify destinations as local or remote. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

C: An unintended root can create inefficient forwarding paths even if STP prevents loops. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

D: Two hosts using the same IPv4 address cause intermittent connectivity and ARP instability. This directly satisfies the requirement: diagnose intermittent access accompanied by duplicate-address warnings.

E: An incorrect next hop for 0.0.0.0/0 sends unknown destinations the wrong way. However, it does not most directly satisfy the requirement in this scenario: diagnose intermittent access accompanied by duplicate-address warnings.

Learning point: Use Duplicate IP address when the key requirement is to diagnose intermittent access accompanied by duplicate-address warnings.