EIGRP Troubleshooting practice questions

A network engineer is troubleshooting an EIGRP adjacency issue between two directly connected routers, R1 and R2. Both routers are configured with the same autonomous system number, but the adjacency fails to come up. The engineer checks the interfaces and verifies that they are up/up. On R1, the output of 'show ip eigrp neighbors' shows nothing. What is the most likely cause of this problem?

Trap 1: The EIGRP process is shut down on one of the routers.

Incorrect because if the process is shut down, 'show ip eigrp neighbors' would still show the local process, but no neighbors. However, the more common cause is mismatched subnets.

Trap 2: The passive-interface default command is configured under the EIGRP…

Incorrect because passive-interface default would suppress hello packets on all interfaces, but the engineer would likely see a different symptom, such as no neighbors and the interface being listed as passive.

Trap 3: The EIGRP router ID is the same on both routers.

Incorrect because a duplicate router ID does not prevent adjacency formation; it only causes issues during route exchange and may cause instability.

A
The interfaces are configured with IP addresses from different subnets.
Correct because EIGRP will not form an adjacency if the interfaces are not in the same subnet, as the hello packets will be dropped.
B
The EIGRP process is shut down on one of the routers.
Why wrong: Incorrect because if the process is shut down, 'show ip eigrp neighbors' would still show the local process, but no neighbors. However, the more common cause is mismatched subnets.
C
The passive-interface default command is configured under the EIGRP process.
Why wrong: Incorrect because passive-interface default would suppress hello packets on all interfaces, but the engineer would likely see a different symptom, such as no neighbors and the interface being listed as passive.
D
The EIGRP router ID is the same on both routers.
Why wrong: Incorrect because a duplicate router ID does not prevent adjacency formation; it only causes issues during route exchange and may cause instability.

Question 2mediummultiple choice

A network engineer is troubleshooting a routing issue in an EIGRP network. Router R1 is not learning a specific route from its neighbor R2, even though R2 has the route in its routing table. The engineer checks the EIGRP topology table on R1 and does not see the route. The output of 'show ip eigrp neighbors' shows that R1 and R2 are adjacent. What should the engineer check next?

Trap 1: Check if the route is being summarized on R2.

Incorrect because summarization would create a summary route, not cause a specific route to be missing from the topology table.

Trap 2: Check if the EIGRP metric for the route is too high.

Incorrect because if the route is not in the topology table at all, it is not being received, not that it is being ignored due to metric.

Trap 3: Check if the route is a connected route on R2.

Incorrect because connected routes are automatically advertised by EIGRP if they are in the EIGRP network statement.

A
Check if a distribute-list in or out is applied under the EIGRP process on R1.
Correct because a distribute-list can filter incoming or outgoing routes, preventing them from being added to the topology table.
B
Check if the route is being summarized on R2.
Why wrong: Incorrect because summarization would create a summary route, not cause a specific route to be missing from the topology table.
C
Check if the EIGRP metric for the route is too high.
Why wrong: Incorrect because if the route is not in the topology table at all, it is not being received, not that it is being ignored due to metric.
D
Check if the route is a connected route on R2.
Why wrong: Incorrect because connected routes are automatically advertised by EIGRP if they are in the EIGRP network statement.

Question 3hardmultiple choice

An engineer is troubleshooting an EIGRP convergence issue. After a link failure, the network takes an unusually long time to converge. The engineer notices that the EIGRP hello and hold timers are set to the default values. The network has many routers in a hub-and-spoke topology. What is the most likely cause of the slow convergence?

Trap 1: The EIGRP stub feature is not enabled on the spoke routers.

Incorrect because stub routing helps reduce query propagation, but it does not directly affect hello/hold timer issues or convergence time due to neighbor count.

Trap 2: The EIGRP variance command is configured, causing unequal-cost load…

Incorrect because variance does not affect convergence time; it only affects path selection.

Trap 3: The EIGRP router ID is not configured, so it defaults to the…

Incorrect because the router ID does not impact convergence time; it is used for route identification.

A
The hub router has too many EIGRP neighbors, causing CPU overload and dropped hello packets.
Correct because a high number of neighbors can overwhelm the hub, leading to missed hello packets and adjacency resets, which prolongs convergence.
B
The EIGRP stub feature is not enabled on the spoke routers.
Why wrong: Incorrect because stub routing helps reduce query propagation, but it does not directly affect hello/hold timer issues or convergence time due to neighbor count.
C
The EIGRP variance command is configured, causing unequal-cost load balancing.
Why wrong: Incorrect because variance does not affect convergence time; it only affects path selection.
D
The EIGRP router ID is not configured, so it defaults to the highest loopback IP.
Why wrong: Incorrect because the router ID does not impact convergence time; it is used for route identification.

Question 4hardmultiple choice

A network engineer is troubleshooting an EIGRP issue where a route is flapping in and out of the routing table. The engineer checks the logs and sees messages indicating that the route is being learned from two different neighbors, but the metric keeps changing. The route is a summary route. What is the most likely cause of the flapping?

Trap 1: The EIGRP stub feature is configured on one of the neighbors.

Incorrect because stub routing prevents the router from being a transit router, but it does not cause route flapping due to metric changes.

Trap 2: The passive-interface command is applied to the interface receiving…

Incorrect because passive-interface would prevent the router from sending hellos, not cause flapping of a learned route.

Trap 3: The EIGRP router ID is the same on both neighbors.

Incorrect because duplicate router IDs can cause route instability, but they would not cause a summary route to flap specifically due to metric changes.

A
The summary route is being advertised by multiple routers with different metrics.
Correct because if the summary route is originated by multiple routers, the metric may vary, causing the router to flap between the best paths.
B
The EIGRP stub feature is configured on one of the neighbors.
Why wrong: Incorrect because stub routing prevents the router from being a transit router, but it does not cause route flapping due to metric changes.
C
The passive-interface command is applied to the interface receiving the summary route.
Why wrong: Incorrect because passive-interface would prevent the router from sending hellos, not cause flapping of a learned route.
D
The EIGRP router ID is the same on both neighbors.
Why wrong: Incorrect because duplicate router IDs can cause route instability, but they would not cause a summary route to flap specifically due to metric changes.

Question 5mediummultiple choice

An engineer is troubleshooting an EIGRP issue where a router is not learning any routes from a neighbor, but the neighbor adjacency is up. The engineer checks the EIGRP topology table on the local router and sees that the neighbor is listed, but no routes from that neighbor are present. The engineer also verifies that the neighbor has routes to advertise. What is the most likely cause?

Trap 1: The local router has a distribute-list out applied to the neighbor.

Incorrect because a distribute-list out would filter routes going out to the neighbor, not incoming routes.

Trap 2: The EIGRP metric weights are different on the two routers.

Incorrect because mismatched metric weights prevent adjacency formation, not route advertisement after adjacency is up.

Trap 3: The local router has a route-map applied to the EIGRP process that…

Incorrect because a route-map applied to the EIGRP process would affect redistribution, not the reception of routes from a neighbor.

A
The neighbor is configured as an EIGRP stub router.
Correct because a stub router only advertises connected and summary routes by default, so if the neighbor has other routes, they will not be advertised.
B
The local router has a distribute-list out applied to the neighbor.
Why wrong: Incorrect because a distribute-list out would filter routes going out to the neighbor, not incoming routes.
C
The EIGRP metric weights are different on the two routers.
Why wrong: Incorrect because mismatched metric weights prevent adjacency formation, not route advertisement after adjacency is up.
D
The local router has a route-map applied to the EIGRP process that is filtering all routes.
Why wrong: Incorrect because a route-map applied to the EIGRP process would affect redistribution, not the reception of routes from a neighbor.

Question 6mediummultiple choice

A network engineer is troubleshooting an EIGRP issue where a router is not installing a route in the routing table, even though the route is present in the EIGRP topology table. The route is a feasible successor, but it is not being used. What is the most likely reason for this?

Trap 1: The route is a summary route that is being suppressed.

Incorrect because summary routes are installed in the routing table if they are the best path.

Trap 2: The route is being filtered by a distribute-list in.

Incorrect because if a route is in the topology table, it has not been filtered by a distribute-list in.

Trap 3: The EIGRP variance command is set to 1, preventing unequal-cost…

Incorrect because variance only affects whether feasible successors are used for load balancing; it does not prevent the successor from being installed.

A
The feasible successor has a higher metric than the current successor.
Correct because EIGRP installs only the route with the lowest metric (successor) into the routing table; feasible successors are kept as backup routes.
B
The route is a summary route that is being suppressed.
Why wrong: Incorrect because summary routes are installed in the routing table if they are the best path.
C
The route is being filtered by a distribute-list in.
Why wrong: Incorrect because if a route is in the topology table, it has not been filtered by a distribute-list in.
D
The EIGRP variance command is set to 1, preventing unequal-cost load balancing.
Why wrong: Incorrect because variance only affects whether feasible successors are used for load balancing; it does not prevent the successor from being installed.

Question 7hardmultiple choice

An engineer is troubleshooting an EIGRP issue where a router is not forming an adjacency with a neighbor over a Frame Relay point-to-point subinterface. The physical interface is up/up, and the subinterface is configured with an IP address. The engineer checks the EIGRP configuration and sees that the network statement includes the subnet of the subinterface. What is the most likely cause of the adjacency failure?

Trap 1: The subinterface is not configured with the 'frame-relay…

Incorrect because the DLCI is needed for Frame Relay, but the adjacency failure is more likely due to the interface type not supporting multicast.

Trap 2: The EIGRP hello timer is set to 0 on the subinterface.

Incorrect because setting the hello timer to 0 would disable hellos, but this is not a common misconfiguration.

Trap 3: The IP address on the subinterface is not in the same subnet as the…

Incorrect because if the subinterface is point-to-point, the IP addresses do not need to be in the same subnet; Frame Relay point-to-point links can use different subnets.

A
The subinterface is not configured with the 'frame-relay interface-dlci' command.
Why wrong: Incorrect because the DLCI is needed for Frame Relay, but the adjacency failure is more likely due to the interface type not supporting multicast.
B
The subinterface is configured as multipoint instead of point-to-point.
Correct because multipoint subinterfaces require additional configuration (like 'frame-relay map' for multicast) to support EIGRP, while point-to-point subinterfaces work with multicast by default.
C
The EIGRP hello timer is set to 0 on the subinterface.
Why wrong: Incorrect because setting the hello timer to 0 would disable hellos, but this is not a common misconfiguration.
D
The IP address on the subinterface is not in the same subnet as the neighbor.
Why wrong: Incorrect because if the subinterface is point-to-point, the IP addresses do not need to be in the same subnet; Frame Relay point-to-point links can use different subnets.

Question 8easymultiple choice

A network engineer is troubleshooting an EIGRP issue where a router is not learning any routes from a neighbor, but the neighbor adjacency is up. The engineer checks the EIGRP topology table and sees that the neighbor is listed, but no routes are present. The engineer also checks the interface configuration and sees that the interface is configured as a passive interface under the EIGRP process. What is the most likely cause of the issue?

Trap 1: The passive-interface command is preventing the router from sending…

Incorrect because passive-interface prevents both sending and receiving hellos, so adjacency would not form.

Trap 2: The EIGRP process is configured with the 'no auto-summary' command.

Incorrect because auto-summary affects route summarization at classful boundaries, not the reception of routes.

Trap 3: The router ID is not configured, so EIGRP is using the highest…

Incorrect because the router ID does not affect the ability to receive routes.

A
The passive-interface command is preventing the router from sending updates, but not receiving them.
Why wrong: Incorrect because passive-interface prevents both sending and receiving hellos, so adjacency would not form.
B
The neighbor is configured with a distribute-list that filters all routes.
Correct because if the adjacency is up but no routes are received, the neighbor is likely filtering the routes it sends.
C
The EIGRP process is configured with the 'no auto-summary' command.
Why wrong: Incorrect because auto-summary affects route summarization at classful boundaries, not the reception of routes.
D
The router ID is not configured, so EIGRP is using the highest loopback IP.
Why wrong: Incorrect because the router ID does not affect the ability to receive routes.

Question 9easymultiple choice

An engineer is troubleshooting an EIGRP issue where a router is not learning a specific route from a neighbor, but other routes from the same neighbor are being learned. The engineer checks the EIGRP topology table and sees that the route is not present. The engineer also checks the neighbor's routing table and confirms that the route exists. What is the most likely cause?

Trap 1: The neighbor is configured as a stub router.

Incorrect because a stub router would not advertise any routes except connected and summary, so all routes would be missing, not just one.

Trap 2: The route is a summary route that is being suppressed by the…

Incorrect because summary-address creates a summary route, it does not suppress a specific route.

Trap 3: The EIGRP metric for the route is too high, so it is not considered…

Incorrect because if the route is not in the topology table at all, it is not being received, not that it is being ignored due to metric.

A
A distribute-list in is applied on the local router that filters the specific route.
Correct because a distribute-list can filter specific routes based on prefix or other criteria.
B
The neighbor is configured as a stub router.
Why wrong: Incorrect because a stub router would not advertise any routes except connected and summary, so all routes would be missing, not just one.
C
The route is a summary route that is being suppressed by the 'summary-address' command.
Why wrong: Incorrect because summary-address creates a summary route, it does not suppress a specific route.
D
The EIGRP metric for the route is too high, so it is not considered feasible.
Why wrong: Incorrect because if the route is not in the topology table at all, it is not being received, not that it is being ignored due to metric.

Question 10mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp neighbors

EIGRP-IPv4 Neighbors for AS(100) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 10.1.1.2 Gi0/0 13 00:12:34 12 200 0 45 1 10.2.2.2 Gi0/1 12 00:10:20 15 200 0 32 2 10.3.3.2 Gi0/2 14 00:08:15 18 200 0 28 3 10.4.4.2 Gi0/3 13 00:06:10 20 200 0 22

Based on this output, which statement is correct?

Trap 1: Neighbor 10.4.4.2 has a high SRTT of 20 ms, indicating a slow link.

An SRTT of 20 ms is normal and not considered high for EIGRP.

Trap 2: The Q Cnt of 0 means that there are 0 packets queued for…

A Q Cnt of 0 is normal and indicates no retransmissions are pending.

Trap 3: The neighbor on Gi0/3 has the lowest uptime, so it may be flapping.

An uptime of 6 minutes is not necessarily indicative of flapping; it could be a recent addition.

A
All four EIGRP neighbors are in the established state and exchanging routes.
All neighbors show a hold time, uptime, SRTT, RTO, and Q Cnt of 0, indicating a stable adjacency.
B
Neighbor 10.4.4.2 has a high SRTT of 20 ms, indicating a slow link.
Why wrong: An SRTT of 20 ms is normal and not considered high for EIGRP.
C
The Q Cnt of 0 means that there are 0 packets queued for retransmission, but this could indicate a problem.
Why wrong: A Q Cnt of 0 is normal and indicates no retransmissions are pending.
D
The neighbor on Gi0/3 has the lowest uptime, so it may be flapping.
Why wrong: An uptime of 6 minutes is not necessarily indicative of flapping; it could be a recent addition.

Question 11hardmultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology

EIGRP-IPv4 Topology Table for AS(100)/ID(192.168.1.1) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

P 10.10.10.0/24, 1 successors, FD is 28160 via 10.1.1.2 (28160/28160), GigabitEthernet0/0 P 10.20.20.0/24, 1 successors, FD is 28160 via 10.2.2.2 (28160/28160), GigabitEthernet0/1 P 10.30.30.0/24, 1 successors, FD is 28160 via 10.3.3.2 (28160/28160), GigabitEthernet0/2 A 10.40.40.0/24, 0 successors, FD is Infinity via 10.4.4.2 (Infinity/Infinity), GigabitEthernet0/3

Based on this output, what is the problem?

Trap 1: The route to 10.40.40.0/24 is passive and stable.

The code 'A' indicates Active, not Passive.

Trap 2: The route to 10.30.30.0/24 has a feasible successor.

The output shows only one successor for 10.30.30.0/24; no feasible successor is listed.

Trap 3: All routes are in a stable passive state.

The route to 10.40.40.0/24 is Active, so not all routes are passive.

A
The route to 10.40.40.0/24 is stuck-in-active and may cause a network instability.
A route in Active state with no successor indicates that the router is querying neighbors and has not received a reply, which can lead to SIA.
B
The route to 10.40.40.0/24 is passive and stable.
Why wrong: The code 'A' indicates Active, not Passive.
C
The route to 10.30.30.0/24 has a feasible successor.
Why wrong: The output shows only one successor for 10.30.30.0/24; no feasible successor is listed.
D
All routes are in a stable passive state.
Why wrong: The route to 10.40.40.0/24 is Active, so not all routes are passive.

Question 12mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp interfaces

EIGRP-IPv4 Interfaces for AS(100) Xmit Queue Mean Pacing Time Multicast Pending

Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes

Gi0/0 1 0/0 12 0/10 50 0 Gi0/1 1 0/0 15 0/10 50 0 Gi0/2 1 0/0 18 0/10 50 0 Gi0/3 1 0/0 20 0/10 50 0 Gi0/4 0 0/0 0 0/10 50 0

Based on this output, which statement is correct?

Trap 1: All interfaces have at least one EIGRP neighbor.

Gi0/4 has 0 peers, so not all interfaces have a neighbor.

Trap 2: The mean SRTT on Gi0/2 is 18 ms, which is too high and indicates a…

18 ms is a normal SRTT value for EIGRP.

Trap 3: The pending routes count of 0 on all interfaces indicates a routing…

A pending routes count of 0 is normal and indicates no routes are waiting to be processed.

A
Interface Gi0/4 has no EIGRP neighbor, which may indicate a configuration issue or lack of connectivity.
A peer count of 0 means no EIGRP adjacency exists on that interface.
B
All interfaces have at least one EIGRP neighbor.
Why wrong: Gi0/4 has 0 peers, so not all interfaces have a neighbor.
C
The mean SRTT on Gi0/2 is 18 ms, which is too high and indicates a problem.
Why wrong: 18 ms is a normal SRTT value for EIGRP.
D
The pending routes count of 0 on all interfaces indicates a routing loop.
Why wrong: A pending routes count of 0 is normal and indicates no routes are waiting to be processed.

Question 13mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp traffic

EIGRP-IPv4 Traffic Statistics for AS(100) Hellos sent/received: 5000/4995 Updates sent/received: 150/148 Queries sent/received: 10/8 Replies sent/received: 8/10 Acks sent/received: 300/298 Input queue high water mark: 10 Input queue drops: 0 SIA-Queries sent/received: 0/0 SIA-Replies sent/received: 0/0 Hello process ID: 123 PDM process ID: 124 Socket queue: 0/2000/10/0 (current/max/highest/drops) Input queue: 0/2000/10/0 (current/max/highest/drops)

Based on this output, which statement is correct?

Trap 1: There is a problem because more queries were sent than replies…

A slight imbalance is normal; the numbers are close and within acceptable range.

Trap 2: The input queue drops of 0 indicate that the router is not…

Input queue drops of 0 mean no packets were dropped, which is good.

Trap 3: The SIA-Queries count of 0 indicates that the network has…

A count of 0 means no SIA events have occurred.

A
The EIGRP process is operating normally with no signs of issues.
No input drops, no SIA events, and balanced packet counts indicate a healthy EIGRP process.
B
There is a problem because more queries were sent than replies received.
Why wrong: A slight imbalance is normal; the numbers are close and within acceptable range.
C
The input queue drops of 0 indicate that the router is not processing EIGRP packets.
Why wrong: Input queue drops of 0 mean no packets were dropped, which is good.
D
The SIA-Queries count of 0 indicates that the network has experienced stuck-in-active events.
Why wrong: A count of 0 means no SIA events have occurred.

Question 14hardmultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp neighbors detail

EIGRP-IPv4 Neighbors for AS(100) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 10.1.1.2 Gi0/0 13 00:12:34 12 200 0 45 Version 12.0/2.0, Retrans: 0, Retries: 0, Restarts: 0 Topology ids from peer: 0 Passive interface: No Hello interval: 5 Hold time: 15

Based on this output, what is the problem?

Trap 1: The interface is configured as passive, preventing neighbor…

The output says 'Passive interface: No', meaning it is not passive.

Trap 2: The neighbor has a high number of retransmissions.

Retransmissions are 0, indicating no issues.

Trap 3: The hold time of 15 seconds is too short and may cause flapping.

The hold time of 15 seconds is the default for EIGRP on LAN interfaces and is acceptable.

A
The neighbor is operating normally with no issues.
All parameters are within normal range, and the neighbor is fully established.
B
The interface is configured as passive, preventing neighbor formation.
Why wrong: The output says 'Passive interface: No', meaning it is not passive.
C
The neighbor has a high number of retransmissions.
Why wrong: Retransmissions are 0, indicating no issues.
D
The hold time of 15 seconds is too short and may cause flapping.
Why wrong: The hold time of 15 seconds is the default for EIGRP on LAN interfaces and is acceptable.

Question 15hardmultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology 10.10.10.0/24

EIGRP-IPv4 Topology Entry for AS(100)/ID(192.168.1.1) for 10.10.10.0/24 State: Passive, Reply status: 0, Originating router: 192.168.1.1 Routing Descriptor Blocks:

0.0.0.0 (Null0) from 0.0.0.0, Send flag: 0x0

Composite metric: (2560000000/0), Route is Internal Vector metric: Minimum bandwidth: 100000 Kbit Total delay: 100 microseconds Reliability: 255/255 Load: 1/255 Minimum MTU: 1500 Hop count: 0

Based on this output, what is the problem?

Trap 1: The route has a metric of 2560000000, indicating a network failure.

A high metric for a null0 route is expected and does not indicate failure.

Trap 2: The hop count of 0 means the route is not reachable.

Hop count of 0 is normal for a directly connected or summary route.

Trap 3: The route is in Active state, indicating a problem.

The state is Passive, which is normal.

A
The route is a local summary route pointing to Null0, which is normal for EIGRP summarization.
EIGRP automatically installs a null0 route for summary addresses to prevent loops.
B
The route has a metric of 2560000000, indicating a network failure.
Why wrong: A high metric for a null0 route is expected and does not indicate failure.
C
The hop count of 0 means the route is not reachable.
Why wrong: Hop count of 0 is normal for a directly connected or summary route.
D
The route is in Active state, indicating a problem.
Why wrong: The state is Passive, which is normal.

Question 16mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology all-links

EIGRP-IPv4 Topology Table for AS(100)/ID(192.168.1.1) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status

P 10.10.10.0/24, 1 successors, FD is 28160, Qos: 0 via 10.1.1.2 (28160/28160), GigabitEthernet0/0 via 10.2.2.2 (28672/28160), GigabitEthernet0/1 P 10.20.20.0/24, 1 successors, FD is 28160, Qos: 0 via 10.2.2.2 (28160/28160), GigabitEthernet0/1 via 10.3.3.2 (28672/28160), GigabitEthernet0/2

Based on this output, which statement is correct?

Trap 1: The route to 10.20.20.0/24 has no feasible successor.

It has a feasible successor via 10.3.3.2.

Trap 2: The FD for 10.10.10.0/24 is 28672.

The FD is 28160, as shown in the output.

Trap 3: The route to 10.10.10.0/24 is in Active state.

The code 'P' indicates Passive state.

A
The network has redundant paths with feasible successors for both routes.
Both routes have a feasible successor, providing backup paths.
B
The route to 10.20.20.0/24 has no feasible successor.
Why wrong: It has a feasible successor via 10.3.3.2.
C
The FD for 10.10.10.0/24 is 28672.
Why wrong: The FD is 28160, as shown in the output.
D
The route to 10.10.10.0/24 is in Active state.
Why wrong: The code 'P' indicates Passive state.

Question 17mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp interfaces detail Gi0/0

EIGRP-IPv4 Interfaces for AS(100)

Interface: GigabitEthernet0/0

Peers: 1 Xmit Queue Un/Reliable: 0/0 Mean SRTT: 12 Pacing Time Un/Reliable: 0/10 Multicast Flow Timer: 50 Pending Routes: 0 Hello interval: 5 Hold time: 15 Split horizon: Enabled Next multicast: 0.0.0.0 Next broadcast: 0.0.0.0

Based on this output, what is the problem?

Trap 1: Split horizon is disabled, which could cause routing loops.

The output shows 'Split horizon: Enabled', not disabled.

Trap 2: The hold time of 15 seconds is too short and may cause instability.

15 seconds is the default hold time for EIGRP on LAN interfaces.

Trap 3: The interface has no peers, indicating a problem.

The output shows 'Peers: 1', so there is one peer.

A
Split horizon is enabled, which is a normal and expected configuration.
Split horizon is enabled by default on EIGRP interfaces and helps prevent routing loops.
B
Split horizon is disabled, which could cause routing loops.
Why wrong: The output shows 'Split horizon: Enabled', not disabled.
C
The hold time of 15 seconds is too short and may cause instability.
Why wrong: 15 seconds is the default hold time for EIGRP on LAN interfaces.
D
The interface has no peers, indicating a problem.
Why wrong: The output shows 'Peers: 1', so there is one peer.

Question 18hardmultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology 10.50.50.0/24

EIGRP-IPv4 Topology Entry for AS(100)/ID(192.168.1.1) for 10.50.50.0/24 State: Active, Reply status: 0, Originating router: 192.168.1.1 Routing Descriptor Blocks:

10.1.1.2 (GigabitEthernet0/0), from 10.1.1.2, Send flag: 0x0

Composite metric: (4294967295/4294967295), Route is Internal Vector metric: Minimum bandwidth: 100000 Kbit Total delay: 100 microseconds Reliability: 255/255 Load: 1/255 Minimum MTU: 1500 Hop count: 1

Based on this output, what is the problem?

Trap 1: The route is passive and stable.

The state is Active, not Passive.

Trap 2: The metric of 4294967295 is normal for a summary route.

Infinity metric indicates unreachability, not a summary.

Trap 3: The hop count of 1 indicates the route is one hop away and…

Despite the hop count, the metric is Infinity, so the route is not reachable.

A
The route is in Active state with an infinite metric, indicating that the router has lost the route and is querying for a new path.
Active state with Infinity metric means the route is unreachable and the router is actively seeking a replacement.
B
The route is passive and stable.
Why wrong: The state is Active, not Passive.
C
The metric of 4294967295 is normal for a summary route.
Why wrong: Infinity metric indicates unreachability, not a summary.
D
The hop count of 1 indicates the route is one hop away and reachable.
Why wrong: Despite the hop count, the metric is Infinity, so the route is not reachable.

Question 19mediummultiple choice

Consider the following EIGRP configuration on Router R1:

router eigrp 100
 network 10.0.0.0
 passive-interface default
 no passive-interface GigabitEthernet0/0

What is the effect of this configuration?

Trap 1: EIGRP will form neighbor adjacencies on all interfaces.

The passive-interface default command prevents neighbor formation on all interfaces unless explicitly removed.

Trap 2: EIGRP will not form any neighbor adjacencies.

GigabitEthernet0/0 is explicitly enabled, so it will form adjacencies.

Trap 3: EIGRP will form neighbor adjacencies on all interfaces except…

The no passive-interface command enables neighbor formation on GigabitEthernet0/0, not disables it.

A
EIGRP will form neighbor adjacencies on all interfaces.
Why wrong: The passive-interface default command prevents neighbor formation on all interfaces unless explicitly removed.
B
EIGRP will form neighbor adjacencies only on GigabitEthernet0/0.
The no passive-interface command on GigabitEthernet0/0 allows neighbor formation only on that interface.
C
EIGRP will not form any neighbor adjacencies.
Why wrong: GigabitEthernet0/0 is explicitly enabled, so it will form adjacencies.
D
EIGRP will form neighbor adjacencies on all interfaces except GigabitEthernet0/0.
Why wrong: The no passive-interface command enables neighbor formation on GigabitEthernet0/0, not disables it.

Question 20mediummultiple choice

Given the following EIGRP configuration on Router R2:

router eigrp 200
 network 192.168.1.0
 network 10.0.0.0
 no auto-summary

Which statement is true about the operation of EIGRP?

Trap 1: EIGRP will automatically summarize 192.168.1.0 to 192.168.0.0/16.

Auto-summary is disabled, so no classful summarization occurs.

Trap 2: EIGRP will only advertise the classful networks 192.168.0.0/16 and…

Auto-summary is disabled, so classful summarization does not occur.

Trap 3: EIGRP will not form neighbor adjacencies due to missing network…

Network statements without a mask use the classful address, which is valid for EIGRP.

A
EIGRP will automatically summarize 192.168.1.0 to 192.168.0.0/16.
Why wrong: Auto-summary is disabled, so no classful summarization occurs.
B
EIGRP will advertise 192.168.1.0/24 and 10.0.0.0/8 as exact prefixes.
With no auto-summary, subnets are advertised without summarization.
C
EIGRP will only advertise the classful networks 192.168.0.0/16 and 10.0.0.0/8.
Why wrong: Auto-summary is disabled, so classful summarization does not occur.
D
EIGRP will not form neighbor adjacencies due to missing network mask.
Why wrong: Network statements without a mask use the classful address, which is valid for EIGRP.