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CCNA Eigrp Questions

58 questions · Eigrp topic · All types, answers revealed

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1
MCQeasy

What is the default EIGRP hello interval on a point-to-point serial link?

A.5 seconds
B.10 seconds
C.30 seconds
D.60 seconds
AnswerA

Correct. The default hello interval for point-to-point serial links is 5 seconds.

Why this answer

The default EIGRP hello interval on a point-to-point serial link is 5 seconds. EIGRP uses different hello intervals depending on the media type: for high-speed broadcast links (e.g., Ethernet) and point-to-point links, the default is 5 seconds; for multipoint non-broadcast links (e.g., Frame Relay), the default is 60 seconds.

Exam trap

Cisco often tests the distinction between EIGRP and OSPF hello intervals, so the trap here is that candidates confuse the 10-second OSPF default with EIGRP's 5-second default on point-to-point links.

How to eliminate wrong answers

Option B (10 seconds) is wrong because 10 seconds is the default hello interval for OSPF on broadcast and point-to-point links, not for EIGRP. Option C (30 seconds) is wrong because 30 seconds is not a standard EIGRP hello interval; it is the default hold time multiplier factor (3x hello) on some links, but not the hello timer itself. Option D (60 seconds) is wrong because 60 seconds is the default EIGRP hello interval only on low-speed multipoint non-broadcast links (e.g., Frame Relay multipoint), not on point-to-point serial links.

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2
MCQhard

An engineer configures EIGRP on a new router in a DMVPN network. The router has a single physical interface with two subinterfaces: one for the DMVPN tunnel and one for a direct point-to-point link to a hub router. The engineer notices that EIGRP adjacencies form only on the point-to-point link, not on the DMVPN tunnel. The tunnel interface is configured with ip nhrp network-id 1 and ip nhrp nhs 10.1.1.1. What is the most likely reason?

A.The tunnel interface is not configured with the 'ip nhrp map' command for the hub router.
B.The tunnel interface is not configured with the 'ip eigrp' command under the interface configuration.
C.The DMVPN tunnel is using a different autonomous system number than the point-to-point link.
D.The tunnel interface is in a different VRF than the point-to-point link.
AnswerB

Correct. For EIGRP to form an adjacency over the tunnel interface, the interface must be included in the EIGRP process, typically with 'ip eigrp <as-number>' under the interface. Without it, EIGRP will not send or receive hello packets on that interface.

Why this answer

Option B is correct because the most common reason for EIGRP not forming an adjacency over a tunnel interface is the absence of the 'ip eigrp' command under that interface. Without this command, EIGRP is not enabled on the tunnel, so it will not send or process Hello packets, preventing adjacency formation even if NHRP and tunnel parameters are correctly configured.

Exam trap

Cisco often tests the distinction between routing protocol configuration (e.g., 'ip eigrp') and tunnel-specific parameters (e.g., NHRP), leading candidates to incorrectly blame NHRP mapping or AS number mismatches when the real issue is the missing EIGRP enable command on the interface.

How to eliminate wrong answers

Option A is wrong because the 'ip nhrp map' command is not required for a hub router in a DMVPN phase 2 or 3 spoke configuration; the spoke uses NHRP to dynamically register with the hub, and the hub's address is already specified with 'ip nhrp nhs'. Option C is wrong because if the autonomous system numbers were different, EIGRP would still attempt to form an adjacency but would fail due to mismatched AS numbers, not fail to initiate the adjacency at all; the question states adjacencies form only on the point-to-point link, implying the tunnel interface is not even attempting to form an adjacency. Option D is wrong because a VRF mismatch would prevent routing information exchange but would not prevent the EIGRP adjacency from forming; EIGRP can form adjacencies across VRFs if configured correctly, and the issue here is that no adjacency forms at all.

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3
Multi-Selecthard

Which three statements about EIGRP packet types are true? (Choose three.)

Select 3 answers
A.Hello packets are sent unreliably and do not require an acknowledgment.
B.Update packets are always sent as multicast to all EIGRP neighbors.
C.Query packets are sent reliably and require a Reply from each neighbor.
D.ACK packets are unicast and are used to acknowledge reliable EIGRP packets.
E.Reply packets are sent unreliably to conserve bandwidth.
AnswersA, C, D

Correct because Hello packets are sent as best-effort (unreliable) and are not acknowledged.

Why this answer

EIGRP uses five packet types: Hello (neighbor discovery/maintenance), Update (route information), Query (ask neighbors for routes), Reply (response to Query), and ACK (acknowledgment). Hello packets are multicast to 224.0.0.10, unacknowledged, and used to form and maintain adjacencies. Update packets are sent reliably (with ACK) and can be multicast or unicast.

Query packets are multicast and require a Reply. ACK packets are unicast and are used to acknowledge reliable packets.

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4
MCQhard

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 10.1.1.0/24, 1 successors, FD is 1310720, serno 5 via 192.168.1.2 (1310720/1310720), GigabitEthernet0/0 via 10.2.2.2 (1587200/1310720), GigabitEthernet0/1 P 10.2.2.0/24, 1 successors, FD is 1310720, serno 6 via 192.168.1.2 (1310720/1310720), GigabitEthernet0/0 via 10.2.2.2 (1587200/1310720), GigabitEthernet0/1 Based on this output, what can be concluded?

A.Both routes have a feasible successor via 10.2.2.2.
B.The route 10.1.1.0/24 has two successors.
C.The alternate path via 10.2.2.2 will be used immediately if the successor fails.
D.The router has two paths to 10.1.1.0/24, but only one is in the routing table.
AnswerD

Only the successor is installed in the routing table; the other path is not used unless the successor fails and queries are sent.

Why this answer

The output shows that for 10.1.1.0/24, the feasible distance (FD) is 1310720 and there is only one successor (the route via 192.168.1.2). The alternate path via 10.2.2.2 has a reported distance (RD) of 1310720, which equals the FD, so it does not satisfy the feasibility condition (RD < FD) and therefore is not a feasible successor. Only the successor route is installed in the routing table.

Exam trap

Cisco often tests the distinction between a successor and a feasible successor, and the trap here is that candidates assume any alternate path with a lower metric than the FD is a feasible successor, but the feasibility condition requires the reported distance to be strictly less than the feasible distance, not less than or equal.

How to eliminate wrong answers

Option A is wrong because the alternate path via 10.2.2.2 has a reported distance equal to the feasible distance, which violates the feasibility condition (RD must be strictly less than FD) and thus is not a feasible successor. Option B is wrong because the output explicitly states '1 successors' for 10.1.1.0/24, meaning there is only one successor, not two. Option C is wrong because the alternate path is not a feasible successor; if the successor fails, EIGRP must send queries and go active for that route before it can use the alternate path, so it will not be used immediately.

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5
Drag & Dropmedium

Drag and drop the steps of EIGRP redistribution from OSPF with metric seeding into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

When redistributing OSPF into EIGRP, you must define a default metric or use a route map. First, configure the EIGRP process, then enter address-family, issue the redistribute command, set the metric, and finally verify the redistributed routes.

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6
MCQmedium

A network engineer runs the following command on Router R1: R1# show ip eigrp interfaces detail EIGRP-IPv4 Interfaces for AS(100) Interface: GigabitEthernet0/0 Mtu: 1500, Bandwidth: 1000000 Kbit, Delay: 100 microseconds Reliability: 255/255, Load: 1/255, Min MTU: 1500 Hello interval: 5 sec, Hold time: 15 sec Next hello in: 3 secs Passive interface: No Split horizon: Enabled Authentication: None Neighbor count: 1 Interface: GigabitEthernet0/1 Mtu: 1500, Bandwidth: 100000 Kbit, Delay: 1000 microseconds Reliability: 255/255, Load: 1/255, Min MTU: 1500 Hello interval: 5 sec, Hold time: 15 sec Next hello in: 1 secs Passive interface: No Split horizon: Enabled Authentication: None Neighbor count: 1 Based on this output, what can be concluded?

A.Both interfaces have the same metric weight for bandwidth and delay.
B.GigabitEthernet0/1 will have a higher EIGRP metric than GigabitEthernet0/0 for the same prefix.
C.Interface Gi0/1 is configured as a passive interface.
D.EIGRP authentication is enabled on both interfaces.
AnswerB

EIGRP metric uses bandwidth and delay; lower bandwidth and higher delay increase the metric.

Why this answer

Option B is correct because EIGRP uses the composite metric formula: metric = (K1 * bandwidth + (K2 * bandwidth) / (256 - load) + K3 * delay) * (K5 / (reliability + K4)). With default K values (K1=K3=1, others=0), the metric simplifies to bandwidth + delay. Gi0/0 has bandwidth 1,000,000 Kbit and delay 100 microseconds, while Gi0/1 has bandwidth 100,000 Kbit and delay 1000 microseconds.

The lower bandwidth and higher delay on Gi0/1 result in a higher metric for the same prefix.

Exam trap

Cisco often tests the misconception that the 'show ip eigrp interfaces detail' command displays the K values or metric weights, when in fact it only shows per-interface parameters like bandwidth and delay, and the K values must be verified separately with 'show ip protocols'.

How to eliminate wrong answers

Option A is wrong because the metric weights (K values) are not shown in the output; the command only displays interface-specific parameters like bandwidth and delay, not the K values themselves. Option C is wrong because the output explicitly shows 'Passive interface: No' for Gi0/1, meaning it is not configured as a passive interface. Option D is wrong because the output shows 'Authentication: None' for both interfaces, indicating no EIGRP authentication is enabled.

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7
MCQmedium

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 10.1.1.0/24, 1 successors, FD is 1310720 via 192.168.1.2 (1310720/1310720), GigabitEthernet0/0 P 10.2.2.0/24, 1 successors, FD is 1310720 via 192.168.1.2 (1310720/1310720), GigabitEthernet0/0 P 10.3.3.0/24, 1 successors, FD is 1310720 via 192.168.1.2 (1310720/1310720), GigabitEthernet0/0 Based on this output, what can be concluded?

A.All routes have a feasible successor.
B.The routes are in Active state, meaning the router is querying for alternate paths.
C.Each route has exactly one successor and no feasible successor.
D.The router is using EIGRP stub routing.
AnswerC

The output shows one successor per route and the RD equals the FD, so no feasible successor.

Why this answer

The output shows each route with a code 'P' (Passive) and exactly one successor, with no feasible successor listed. In EIGRP, a feasible successor is only present if there is a backup route that satisfies the feasibility condition (reported distance < feasible distance). Since only one next-hop is shown per route and no additional entries exist, there is no feasible successor.

Option C correctly identifies this.

Exam trap

Cisco often tests the distinction between Passive and Active states in EIGRP topology table output, where candidates mistakenly think 'P' stands for 'Primary' or 'Path' instead of 'Passive', leading them to misinterpret the route state and miss the absence of feasible successors.

How to eliminate wrong answers

Option A is wrong because the output does not show any feasible successor; each route has only one successor and no backup path, so the statement 'All routes have a feasible successor' is false. Option B is wrong because the routes are in Passive state (code 'P'), not Active; Active state would indicate the router is actively querying neighbors for alternate paths, which is not the case here. Option D is wrong because the output does not indicate stub routing; EIGRP stub routing is configured with the 'eigrp stub' command and would not be evident from the topology table alone, and the routes are normal learned routes, not stub-specific behavior.

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8
MCQeasy

A network engineer is troubleshooting an EIGRP issue where two routers, R1 and R2, are directly connected. R1 shows an EIGRP adjacency with R2, but R2 does not show an adjacency with R1. The engineer checks the interface configurations and finds that R1 has 'ip authentication mode eigrp 1 md5' and 'ip authentication key-chain eigrp 1 MYKEY' configured, while R2 has no authentication configured. What is the most likely cause?

A.R1 has authentication configured, but R2 does not, so R1 will reject R2's hello packets, and no adjacency forms.
B.R2 will automatically learn the authentication key from R1 and form an adjacency.
C.R1 will form an adjacency with R2 because authentication is optional.
D.The adjacency will form but only for routes that are not authenticated.
AnswerA

Correct. EIGRP authentication requires both sides to have matching authentication. Since R2 does not have authentication, R1 will discard R2's hello packets, preventing adjacency.

Why this answer

EIGRP authentication is configured per interface and must match on both sides for an adjacency to form. R1 has MD5 authentication enabled, so it will include the authentication data in its hello packets and will reject any hello packets received from R2 that lack the correct authentication. Since R2 has no authentication configured, its hello packets are sent without authentication data, causing R1 to discard them.

Consequently, R1 sees R2 as a neighbor (because it receives R2's unauthenticated hellos and may still attempt to form adjacency depending on implementation), but R2 never receives a valid hello from R1 (because R1's hellos are authenticated and R2 does not process the authentication field), so R2 does not establish an adjacency with R1.

Exam trap

Cisco often tests the misconception that authentication is optional or that a router can learn keys dynamically; the trap here is assuming that an adjacency can form unidirectionally when authentication is mismatched, when in fact EIGRP requires matching authentication parameters for bidirectional neighbor discovery.

How to eliminate wrong answers

Option B is wrong because EIGRP does not support automatic key learning; authentication keys must be manually configured on both routers. Option C is wrong because when authentication is enabled on one side, it is not optional—the receiving router will drop unauthenticated or mismatched hello packets, preventing adjacency formation. Option D is wrong because EIGRP authentication applies to all EIGRP packets (including hellos and updates); there is no mechanism to form an adjacency for only a subset of routes.

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9
Matchingmedium

Drag and drop each EIGRP metric component on the left to its matching variable on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Bandwidth

Load

Delay

Reliability

MTU

Why these pairings

K1 is bandwidth, K2 is load, K3 is delay, K4 is reliability, K5 is MTU.

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10
MCQmedium

A network engineer is troubleshooting an EIGRP issue in a large enterprise network. Two routers, R1 and R2, are connected via a T1 link. R1 is learning a route to 10.0.0.0/8 from R2 with a metric of 28160, but the same route is also learned from another neighbor with a metric of 26880. The engineer notices that the route from R2 is not being installed in the routing table. What is the most likely cause?

A.The route from R2 is a feasible successor, so it is not installed in the routing table.
B.EIGRP is using unequal-cost load balancing, so the higher metric route is not used.
C.The route with metric 28160 is not installed because EIGRP selects the route with the lowest metric.
D.The route from R2 is a summary route, so it is not installed in the routing table.
AnswerC

Correct. EIGRP installs only the route with the best (lowest) metric in the routing table. Since 26880 is lower than 28160, the route from R2 is not installed.

Why this answer

C is correct because EIGRP installs only the route with the best (lowest) metric into the routing table. The route from R2 has a metric of 28160, while the other neighbor advertises the same route with a metric of 26880. Since 26880 is lower, R1 selects that route as the successor and does not install the higher-metric route from R2.

Exam trap

Cisco often tests the misconception that all learned EIGRP routes are installed in the routing table, but in reality only the successor (lowest metric) is installed unless unequal-cost load balancing is explicitly configured.

How to eliminate wrong answers

Option A is wrong because a feasible successor is a backup route that is kept in the topology table but not installed in the routing table unless the successor fails; however, the question states that the route from R2 is not installed, but it is not necessarily a feasible successor—it could simply be a non-successor route that does not meet the feasibility condition. Option B is wrong because unequal-cost load balancing (variance) is optional and, even if enabled, would only load-balance across routes that meet the variance multiplier; the route with metric 28160 would still not be installed if it is not selected as a successor or feasible successor under the variance condition. Option D is wrong because there is no indication that the route from R2 is a summary route; summary routes are typically installed with a lower administrative distance or as a local route, and the metric difference alone does not imply summarization.

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11
Multi-Selectmedium

Which two statements about EIGRP route summarization are true? (Choose two.)

Select 2 answers
A.Manual summarization can be configured on a per-interface basis using the ip summary-address eigrp command.
B.Automatic summarization is enabled by default in EIGRP for IPv4.
C.A manually configured summary route in EIGRP has an administrative distance of 5.
D.Manual summarization causes the router to advertise all specific routes in addition to the summary.
E.EIGRP for IPv6 does not support manual summarization.
AnswersA, C

Correct because the command 'ip summary-address eigrp <as> <prefix> <mask>' is used to configure manual summarization on an interface.

Why this answer

EIGRP supports manual summarization on any interface, which creates a summary route with an administrative distance of 5 by default. Automatic summarization at classful boundaries is disabled by default in modern IOS versions. Manual summarization can be configured per interface and suppresses more specific routes from being advertised out that interface.

The summary route is installed in the routing table as a local route.

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12
Drag & Dropmedium

Drag and drop the steps of EIGRP authentication using MD5 key-chain into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

First, a key chain must be created and a key defined with the MD5 key string. Then, the key chain is applied to the EIGRP interface under router configuration. Finally, authentication mode and key chain are enabled on the interface.

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13
MCQmedium

A network engineer is configuring EIGRP on a router that connects to multiple remote sites via Frame Relay. The engineer wants to ensure that EIGRP does not form adjacencies over the Frame Relay interfaces to reduce overhead, but still wants to advertise the connected networks. The engineer applies the 'passive-interface' command to the Frame Relay interfaces. However, the remote sites stop receiving the routes. What is the most likely reason?

A.The 'passive-interface' command also prevents EIGRP from sending routing updates on that interface.
B.The 'passive-interface' command only affects hello packets, not updates, but the remote sites are not configured correctly.
C.The engineer should use the 'neighbor' command under the EIGRP process to specify the remote routers.
D.The remote sites are using a different EIGRP autonomous system number.
AnswerA

Correct. The passive-interface command suppresses both hello packets and routing updates. Therefore, the remote sites do not receive the routes.

Why this answer

The 'passive-interface' command in EIGRP prevents both hello and routing updates from being sent on the specified interface. Since EIGRP relies on hello packets to form and maintain neighbor adjacencies, applying this command to the Frame Relay interfaces stops adjacency formation. Without an adjacency, no routes are exchanged, so the remote sites stop receiving the advertised networks.

Exam trap

Cisco often tests the misconception that 'passive-interface' only affects routing updates but not hello packets, leading candidates to think adjacencies can still form and routes can be received.

How to eliminate wrong answers

Option A is correct because the 'passive-interface' command suppresses both hello and routing updates, breaking adjacency. Option B is wrong because the 'passive-interface' command does affect updates, not just hello packets; it suppresses all EIGRP traffic on the interface, including updates. Option C is wrong because the 'neighbor' command is used for EIGRP over non-broadcast multi-access (NBMA) networks like Frame Relay to define static neighbors, but it does not override the 'passive-interface' command; the interface would still be passive and no packets would be sent.

Option D is wrong because if the remote sites used a different autonomous system number, they would never form adjacencies regardless of the passive-interface command; the question states they were receiving routes before the change, so the AS numbers must match.

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14
Drag & Dropmedium

Drag and drop the steps of EIGRP stub configuration for hub-and-spoke into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

The correct order ensures that the spoke router first enters EIGRP configuration, then configures the stub feature, optionally restricts stub types, and finally applies the configuration. The hub router does not need stub configuration.

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15
Multi-Selecthard

Which three statements about EIGRP stub routing are true? (Choose three.)

Select 3 answers
A.A stub router does not send Query packets to its neighbors.
B.A hub router will send queries to a stub router when a route is lost.
C.The 'eigrp stub' command can be configured with the 'connected' keyword to advertise only connected routes.
D.Stub routing is used to reduce the size of the routing table on the hub router.
E.A stub router can be configured as 'receive-only' to not advertise any routes.
AnswersA, C, E

Correct because stub routers are not allowed to originate queries; they rely on the hub for routing information.

Why this answer

EIGRP stub routing is used to limit the query scope and improve convergence. A stub router is typically a spoke in a hub-and-spoke topology. It advertises its directly connected and summary routes to the hub, but does not query its neighbors.

The hub router does not send queries to the stub router. The stub router can be configured with different options: connected, static, summary, receive-only, or redistributed. The 'eigrp stub' command enables this feature.

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16
Multi-Selecthard

Which three statements about EIGRP named mode configuration are true? (Choose three.)

Select 3 answers
A.Named mode uses the 'router eigrp <name>' command to enter configuration mode.
B.In named mode, the network statement is replaced by the 'af-interface' configuration under the address family.
C.Named mode supports both IPv4 and IPv6 address families within the same EIGRP process.
D.The 'address-family ipv4' command is used to enter IPv4 configuration under named mode.
E.Named mode requires the 'no shutdown' command under the address family to enable EIGRP.
AnswersA, C, D

Correct because named mode starts with 'router eigrp <name>', where <name> is a case-sensitive tag.

Why this answer

EIGRP named mode uses a hierarchical configuration under a single router process, supporting address families (IPv4, IPv6) and VRFs. It simplifies configuration and allows per-interface settings.

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17
MCQmedium

A network engineer is designing an EIGRP network with multiple routers. The network has a core layer where all routers are fully meshed. The engineer wants to ensure that if a link fails, EIGRP converges quickly without relying on route redistribution or static routes. The engineer configures EIGRP with default timers. However, during a failure simulation, convergence takes over 15 seconds. What is the most likely reason?

A.EIGRP is using passive interfaces on the core routers, preventing rapid updates.
B.The failed link was the only feasible successor for the affected routes, causing EIGRP to go into active state and query neighbors.
C.EIGRP hold timers are set to 180 seconds by default, causing slow detection.
D.The engineer configured 'eigrp stub' on the core routers, which prevents query propagation.
AnswerB

Correct. When the only feasible successor fails, EIGRP transitions to active state and sends queries to all neighbors. The time to receive all replies can exceed 15 seconds, especially in large networks.

Why this answer

When the only feasible successor (FS) for a route fails, EIGRP cannot perform a local recomputation and must transition the route to the active state. It then sends query packets to all neighbors to find an alternative path, which introduces significant delay due to the need to wait for replies from every neighbor in a fully meshed core. With default timers, this query/reply process can easily exceed 15 seconds, especially if any neighbor is slow to respond.

Exam trap

Cisco often tests the misconception that EIGRP convergence is always fast due to its DUAL algorithm, but the trap here is that without a feasible successor, the active query process can cause significant delays, especially in a fully meshed network.

How to eliminate wrong answers

Option A is wrong because passive interfaces suppress the sending of EIGRP hellos and updates, which would prevent neighbor formation entirely, not just slow convergence; the scenario implies neighbors are established. Option C is wrong because the default EIGRP hold timer is 15 seconds (not 180 seconds), and even if it were longer, the failure detection delay alone would not account for a 15-second convergence time when the primary issue is query propagation. Option D is wrong because configuring 'eigrp stub' on core routers would actually speed convergence by preventing query propagation, not slow it; stubs do not propagate queries, so they reduce the active-state delay.

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18
Drag & Dropmedium

Drag and drop the steps of EIGRP authentication using MD5 key-chain into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

EIGRP MD5 authentication requires first defining a key chain with keys, then applying the key chain to the EIGRP process, enabling authentication on the interface, and finally verifying the authentication status.

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19
Drag & Dropmedium

Drag and drop the steps of EIGRP named mode configuration steps into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

EIGRP named mode uses an address-family configuration. First, create the named EIGRP instance, then enter address-family IPv4, configure the network, optionally adjust timers, and finally verify the configuration.

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20
MCQmedium

A network engineer is designing an EIGRP network with multiple routers in a hub-and-spoke topology. The engineer wants to ensure that the spoke routers do not become transit routers for traffic between other spokes. The engineer configures 'eigrp stub' on the spoke routers. However, after configuration, the spoke routers stop learning some routes from the hub. What is the most likely reason?

A.The spoke routers are configured with 'eigrp stub receive-only', which prevents them from advertising any routes, so the hub does not have routes to the spoke's networks.
B.The 'eigrp stub' command prevents the spoke from learning routes from the hub.
C.The hub router is also configured as stub, which prevents route propagation.
D.The spoke routers have a different EIGRP autonomous system number than the hub.
AnswerA

Correct. The 'receive-only' keyword prevents the spoke from advertising any routes, including its connected networks. The hub then cannot reach the spoke's networks, and the spoke may not learn routes that depend on those advertisements.

Why this answer

The 'eigrp stub receive-only' command configures the spoke router to only receive routes and not advertise any of its own networks. This causes the hub router to lack routes to the spoke's directly connected or summarized networks, breaking reachability from the hub to the spoke. The correct answer is A because this specific stub mode prevents the spoke from advertising any routes, which is the most likely reason the spoke stops learning some routes from the hub (since the hub may not have a route back to the spoke's networks).

Exam trap

Cisco often tests the misconception that 'eigrp stub' prevents a router from learning routes, when in fact it only restricts the routes the router advertises, and the 'receive-only' keyword is the specific variant that stops all advertisements, causing the hub to lack routes to the spoke's networks.

How to eliminate wrong answers

Option A is correct as explained. Option B is wrong because the 'eigrp stub' command (without 'receive-only') actually allows the spoke to learn routes from the hub; it only restricts the spoke from acting as a transit router by limiting the routes it advertises (e.g., connected, summary). Option C is wrong because configuring the hub as a stub would prevent the hub from learning routes from spokes, but the question states the spoke routers stop learning routes from the hub, which is not caused by the hub being a stub.

Option D is wrong because if the spoke and hub had different EIGRP autonomous system numbers, they would not form an adjacency at all, and the spoke would not learn any routes from the hub—this is a fundamental configuration mismatch, not a subtle effect of the stub command.

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21
MCQmedium

Consider the following EIGRP configuration on a Cisco IOS router: router eigrp 100 network 10.0.0.0 passive-interface default no passive-interface GigabitEthernet0/1 What is the effect of this configuration?

A.All interfaces except GigabitEthernet0/1 are passive and will not form EIGRP adjacencies.
B.EIGRP hellos are sent on all interfaces, but GigabitEthernet0/1 is prevented from forming adjacencies.
C.Only the network 10.0.0.0 is advertised, and all interfaces are passive.
D.EIGRP will only form adjacencies on interfaces with an IP address in the 10.0.0.0/8 range.
AnswerA

Correct. The default passive setting applies to all interfaces, and the exception is made only for GigabitEthernet0/1.

Why this answer

The 'passive-interface default' command sets all interfaces to passive by default, preventing them from sending EIGRP hellos and forming adjacencies. The 'no passive-interface GigabitEthernet0/1' command then overrides this default for that specific interface, allowing it to send hellos and form adjacencies. Therefore, only GigabitEthernet0/1 is active for EIGRP neighbor discovery, while all other interfaces remain passive.

Exam trap

Cisco often tests the interaction between 'passive-interface default' and 'no passive-interface' to see if candidates understand that the default command makes all interfaces passive, and the 'no' form selectively activates only the specified interface, rather than the reverse.

How to eliminate wrong answers

Option B is wrong because it reverses the logic: 'passive-interface default' prevents hellos on all interfaces by default, not sends them, and 'no passive-interface' enables hellos on the specified interface, not prevents them. Option C is wrong because the 'network 10.0.0.0' command enables EIGRP on any interface whose IP address falls within the 10.0.0.0/8 range, but the passive-interface configuration still controls whether hellos are sent and adjacencies formed; the configuration does not make all interfaces passive—only the default passive setting does, which is overridden for GigabitEthernet0/1. Option D is wrong because the 'network 10.0.0.0' command does not restrict adjacency formation to only 10.0.0.0/8 interfaces; it enables EIGRP on those interfaces, but the passive-interface default command would still prevent adjacencies on all interfaces except GigabitEthernet0/1, regardless of their IP address range.

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22
MCQmedium

Examine the following EIGRP configuration for route summarization: interface GigabitEthernet0/0 ip summary-address eigrp 100 192.168.0.0 255.255.252.0 What is the effect of this command?

A.EIGRP will advertise the 192.168.0.0/22 summary route out of GigabitEthernet0/0 and create a discard route.
B.EIGRP will only accept routes within the 192.168.0.0/22 range on this interface.
C.The summary route will have a metric equal to the best metric among the component routes.
D.This command will cause EIGRP to automatically summarize routes to their classful boundaries.
AnswerA

Correct. The summary-address command creates a summary route and a corresponding discard route.

Why this answer

Option A is correct because the `ip summary-address eigrp` command creates a summary route (192.168.0.0/22) that EIGRP advertises out of the specified interface, and it automatically installs a discard (null0) route to prevent routing loops when the summary is advertised but some component routes may not be present in the routing table.

Exam trap

Cisco often tests the misconception that `ip summary-address eigrp` filters incoming routes or that it sets the summary metric to the highest metric, when in fact it creates a discard route and uses the minimum metric from component routes.

How to eliminate wrong answers

Option B is wrong because the command does not filter incoming routes; it only summarizes routes being advertised outbound. Option C is wrong because the summary route's metric is set to the minimum metric among the component routes, not the best (which could be interpreted as highest or best path). Option D is wrong because this command configures manual summarization, not automatic classful summarization; automatic summarization is controlled by the `auto-summary` command.

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23
MCQeasy

What is the default hold time multiplier for EIGRP?

A.3
B.4
C.5
D.10
AnswerA

Correct. The hold time is typically three times the hello interval, so the multiplier is 3.

Why this answer

The default hold time multiplier for EIGRP is 3. This multiplier is applied to the hello interval to calculate the hold time (hold time = hello interval × multiplier). By default, EIGRP uses a hello interval of 5 seconds on most interfaces (or 60 seconds on low-speed NBMA interfaces), so the default hold time is 15 seconds (5 × 3) or 180 seconds (60 × 3).

Exam trap

Cisco often tests the default hold time multiplier (3) versus the default hold time (15 seconds), causing candidates to confuse the multiplier with the actual hold time value or to mistakenly recall the default hello interval (5 seconds) as the multiplier.

How to eliminate wrong answers

Option B (4) is wrong because the default EIGRP hold time multiplier is not 4; a multiplier of 4 would result in a hold time of 20 seconds (5 × 4), which is not the Cisco default. Option C (5) is wrong because a multiplier of 5 would yield a hold time of 25 seconds (5 × 5), which is not the standard default value. Option D (10) is wrong because a multiplier of 10 would produce a hold time of 50 seconds (5 × 10), far exceeding the default 15 seconds; this value is not used as the default multiplier in EIGRP.

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24
MCQmedium

Given the following EIGRP named mode configuration: router eigrp TEST address-family ipv4 unicast autonomous-system 100 network 10.0.0.0 0.255.255.255 topology base distance eigrp 90 170 exit-address-family Which statement is true?

A.The administrative distance for internal EIGRP routes is set to 90, and for external routes to 170.
B.The network statement will enable EIGRP on all interfaces with an IP address starting with 10.
C.The autonomous-system number must match the process ID in classic mode.
D.The 'topology base' command is optional and can be omitted.
AnswerA

Correct. The distance eigrp command sets internal AD to 90 and external AD to 170.

Why this answer

Option A is correct because the 'distance eigrp 90 170' command explicitly sets the administrative distance for internal EIGRP routes to 90 and for external EIGRP routes to 170. This overrides the default values of 90 for internal and 170 for external routes, but in this configuration, the values are set to the same defaults, so the statement accurately describes the configured distances.

Exam trap

Cisco often tests the mandatory nature of the 'topology base' command in EIGRP named mode, as candidates mistakenly think it is optional or only needed for advanced features, but it is required to complete the address-family configuration.

How to eliminate wrong answers

Option B is wrong because the network statement 'network 10.0.0.0 0.255.255.255' uses a wildcard mask that matches only the first octet (10.x.x.x), but EIGRP named mode enables EIGRP only on interfaces whose primary IP address falls within the specified range; it does not enable EIGRP on all interfaces with an IP starting with 10 if the interface is not in the specified subnet. Option C is wrong because in EIGRP named mode, the autonomous-system number is specified within the address-family and does not need to match a classic mode process ID; classic mode uses 'router eigrp <ASN>' directly, while named mode separates the router name from the ASN. Option D is wrong because the 'topology base' command is mandatory in EIGRP named mode; it defines the base topology for the address-family and cannot be omitted, as it is required to enter the topology configuration mode where routing policies are applied.

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25
MCQmedium

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 0 192.168.1.2 Gi0/0 13 00:12:34 12 100 0 45 1 10.1.1.2 Gi0/1 12 00:10:20 15 120 0 32 Based on this output, what can be concluded?

A.Both neighbors are using MD5 authentication.
B.Neighbor 192.168.1.2 has a higher metric than 10.1.1.2.
C.Both neighbors are fully established and exchanging routing information.
D.Router R1 is using EIGRP named mode.
AnswerC

The 'Q Cnt' of 0 and valid uptime indicate stable adjacencies.

Why this answer

The 'show ip eigrp neighbors' output displays two neighbors in a stable state, indicated by the 'Q Cnt' (Queue Count) of 0 for both, meaning no packets are waiting to be sent. The 'Seq Num' (Sequence Number) values (45 and 32) show that R1 has received and processed EIGRP updates from each neighbor, confirming the adjacency is fully established and routing information is being exchanged. This output does not provide any metric or authentication details, so only the conclusion that both neighbors are fully operational is valid.

Exam trap

Cisco often tests the misconception that the 'show ip eigrp neighbors' output reveals authentication status or metric values, but the table only shows transport-layer reliability statistics and adjacency state, not security or routing metric details.

How to eliminate wrong answers

Option A is wrong because the 'show ip eigrp neighbors' output does not include any authentication type or key information; MD5 or SHA authentication status is verified with 'show ip eigrp interfaces detail' or 'show key chain', not from the neighbor table. Option B is wrong because the neighbor table does not display route metrics; metrics are shown per route in the topology table ('show ip eigrp topology') or routing table, and the SRTT/RTO values here are timers for reliable transport, not metrics. Option D is wrong because the output shows 'EIGRP-IPv4 Neighbors for AS(100)', which is the classic EIGRP configuration format; named mode EIGRP would display 'EIGRP-IPv4 VR-FOO Neighbors' or similar with a VRF or named instance, not just the AS number.

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26
Drag & Dropmedium

Drag and drop the steps of EIGRP stub configuration for hub-and-spoke into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

In hub-and-spoke EIGRP, the spoke router is configured as a stub to limit query propagation. First, enter router configuration mode, then enable EIGRP on the spoke, configure it as a stub, optionally restrict advertised routes, and finally verify the stub status.

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27
Matchingmedium

Drag and drop each EIGRP router role on the left to its matching definition on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Next-hop router with the lowest metric for a destination

Backup next-hop router meeting the feasibility condition

Directly connected EIGRP router exchanging Hello packets

Router is actively querying for a route

Router has a valid route and is not querying

Why these pairings

Successor is the next-hop router with the lowest metric; Feasible Successor is a backup that meets the feasibility condition; Neighbor is a directly connected EIGRP router.

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28
Matchingmedium

Drag and drop each EIGRP router role on the left to its matching definition on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Next-hop router for the best route to a destination

Backup next-hop router meeting the feasibility condition

Directly connected EIGRP router exchanging Hello packets

Lowest metric to a destination from the local router

Metric advertised by a neighbor for a specific route

Why these pairings

A successor is the next-hop router for the best route; a feasible successor is a backup route meeting the feasibility condition; a neighbor is a directly connected EIGRP router.

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29
Matchingmedium

Drag and drop each EIGRP timer on the left to its matching default value on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

5 seconds

15 seconds

3 minutes

5 seconds

0.5 seconds

Why these pairings

Hello timer default is 5 seconds on LAN; Hold timer default is 15 seconds (3x Hello); Active timer default is 3 minutes; Update timer default is 5 seconds; Retransmission timer default is 0.5 seconds.

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30
MCQmedium

A network engineer runs the following command on Router R1: R1# show ip eigrp interfaces EIGRP-IPv4 Interfaces for AS(100) Interface Peers Xmit Queue Mean Pacing Time Multicast Pending 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 55 0 Based on this output, what can be concluded?

A.Interface Gi0/1 has higher latency than Gi0/0.
B.Both interfaces have pending routes to send.
C.The router is using EIGRP named mode.
D.There is a queue backlog on Gi0/0.
AnswerA

The Mean SRTT is higher on Gi0/1 (15 ms) compared to Gi0/0 (12 ms), indicating higher round-trip time.

Why this answer

The 'Mean SRTT' (Smooth Round-Trip Time) column shows the average time in milliseconds for EIGRP packets to reach a neighbor and receive an acknowledgment. Gi0/1 has an SRTT of 15 ms, while Gi0/0 has an SRTT of 12 ms, indicating higher latency on Gi0/1. This directly correlates to the path's delay, which EIGRP uses in its composite metric calculation.

Exam trap

Cisco often tests the ability to interpret the 'show ip eigrp interfaces' output, specifically the 'Mean SRTT' column, and the trap here is that candidates confuse SRTT with interface bandwidth or fail to recognize that a higher SRTT means higher latency, not necessarily a problem with queue or pending routes.

How to eliminate wrong answers

Option B is wrong because the 'Pending Routes' column shows 0 for both interfaces, meaning no routes are waiting to be sent. Option C is wrong because the command output shows 'EIGRP-IPv4 Interfaces for AS(100)', which is the classic mode format; named mode would display 'EIGRP-IPv4 (Address Family)' or similar. Option D is wrong because the 'Xmit Queue Un/Reliable' column shows 0/0 for Gi0/0, indicating no queue backlog.

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31
Matchingmedium

Drag and drop each EIGRP packet type on the left to its matching function on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Discovers and maintains neighbor relationships

Sends routing information to neighbors

Requests information about a lost route

Responds to a query with routing information

Acknowledges receipt of a reliable packet

Why these pairings

Hello packets discover and maintain neighbors; Update packets carry routing information; Query packets ask for alternate paths; Reply packets respond to queries; ACK packets acknowledge reliable delivery.

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32
MCQhard

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 0 192.168.1.2 Gi0/0 13 00:12:34 12 100 0 45 Version 2.0/2.0, Retrans: 0, Retry: 0, Maxseq: 0 Prefixes: 3 Topology ids: 0 Authentication: None Topology: base (0x0) Based on this output, what can be concluded?

A.The neighbor is using EIGRP version 1.
B.The neighbor has advertised 3 prefixes to R1.
C.There is a high number of retransmissions indicating packet loss.
D.The neighbor is using MD5 authentication.
AnswerB

The 'Prefixes: 3' field indicates the number of prefixes learned from this neighbor.

Why this answer

The output shows 'Prefixes: 3' under the neighbor details, which indicates that the neighbor has advertised exactly three prefixes to R1. This is a direct interpretation of the 'show ip eigrp neighbors detail' command, where the 'Prefixes' field lists the number of routes learned from that neighbor.

Exam trap

Cisco often tests the ability to read the 'show ip eigrp neighbors detail' output carefully, where candidates may confuse the 'Prefixes' field with the number of interfaces or ignore the 'Retrans' and 'Authentication' fields, leading them to select incorrect options based on assumptions rather than the explicit data shown.

How to eliminate wrong answers

Option A is wrong because the output shows 'Version 2.0/2.0', meaning both R1 and the neighbor are running EIGRP version 2, not version 1. Option C is wrong because the 'Retrans: 0' and 'Retry: 0' fields indicate zero retransmissions and retries, which means no packet loss is occurring. Option D is wrong because the output explicitly states 'Authentication: None', so MD5 authentication is not configured.

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33
Drag & Dropmedium

Drag and drop the steps of EIGRP named mode configuration steps into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

Named mode starts with the router eigrp <virtual-name> command, then enters address-family configuration, configures the network, and optionally adjusts timers or other parameters. Finally, the configuration is verified.

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34
Matchingmedium

Drag and drop each EIGRP timer on the left to its matching default value on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

5 seconds

15 seconds

3 minutes

60 seconds

180 seconds

Why these pairings

Hello timer default is 5 seconds on LAN; Hold timer default is 15 seconds; Active timer default is 3 minutes.

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35
Multi-Selectmedium

Which two statements about EIGRP feasible successors are true? (Choose two.)

Select 2 answers
A.A feasible successor must have a reported distance less than the feasible distance.
B.A feasible successor is immediately used when the successor fails, without any query process.
C.The feasible distance is the metric of the feasible successor route.
D.EIGRP will always have at least one feasible successor for every route.
E.The feasible successor is stored in the routing table as a backup route.
AnswersA, B

Correct because the feasibility condition requires the reported distance (neighbor's metric) to be strictly less than the feasible distance (the current best metric).

Why this answer

A feasible successor is a backup route that meets the feasibility condition (reported distance < feasible distance). It is stored in the topology table and can be used immediately if the successor fails, without querying neighbors. The feasible distance is the lowest metric to a destination; the successor is the route with that metric.

The reported distance is the neighbor's metric to the destination.

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36
Matchingmedium

Drag and drop each EIGRP metric component on the left to its matching K variable on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

K1

K2

K3

K4

K5

Why these pairings

K1 is bandwidth, K2 is load, K3 is delay, K4 is reliability, K5 is MTU.

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37
Drag & Dropmedium

Drag and drop the steps of EIGRP variance-based unequal-cost load balancing into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

To enable unequal-cost load balancing, first ensure feasible successors exist, then set the variance multiplier, optionally adjust the metric offset, and finally verify the load sharing across multiple paths.

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38
Drag & Dropmedium

Drag and drop the steps of EIGRP DUAL route computation into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

EIGRP DUAL first identifies feasible successors via reported distance, then selects the best path as successor. If the successor fails, it checks feasible successors; if none exist, it goes active and queries neighbors. After replies, it computes a new successor.

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39
MCQmedium

An engineer is troubleshooting an EIGRP convergence issue in a network with redundant links. The engineer notices that when a primary link fails, the backup link takes over immediately, but the routing table shows the route with a higher metric. The engineer wants to ensure that the backup link is used only when the primary fails, and that traffic is not load-balanced. The engineer has configured 'variance 2' on all routers. What is the most likely effect of this configuration?

A.The variance 2 command causes EIGRP to install only the best metric route, so the backup link is not used.
B.The variance 2 command causes EIGRP to install both the primary and backup routes, resulting in unequal-cost load balancing.
C.The variance 2 command has no effect on route installation; it only affects the feasible successor selection.
D.The variance 2 command is used for equal-cost load balancing only.
AnswerB

Correct. With variance 2, if the backup route's metric is within twice the best metric, it will be installed and used for load balancing, which the engineer does not want.

Why this answer

The 'variance 2' command in EIGRP allows the router to install multiple routes to the same destination network in the routing table, even if their metrics are not equal, as long as the metric of the alternate route is within the variance multiplier (2x) of the best metric (the feasible distance). Since the backup link has a higher metric but is within the variance, EIGRP installs both routes, causing unequal-cost load balancing. This explains why the backup link is actively used for traffic, contrary to the engineer's desire to use it only as a failover.

Exam trap

Cisco often tests the misconception that 'variance' only affects feasible successor selection or that it is used for equal-cost load balancing, when in fact it directly controls the installation of multiple unequal-cost paths into the routing table.

How to eliminate wrong answers

Option A is wrong because the 'variance 2' command does not restrict EIGRP to only the best metric route; it explicitly allows additional routes with higher metrics to be installed. Option C is wrong because the variance command directly affects route installation by allowing multiple routes into the routing table, not just feasible successor selection (which is controlled by the feasibility condition and the 'metric' command). Option D is wrong because the variance command is specifically designed for unequal-cost load balancing, not equal-cost load balancing (which is the default behavior without variance).

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40
MCQhard

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: 1000/950 Updates sent/received: 45/40 Queries sent/received: 2/3 Replies sent/received: 3/2 Acks sent/received: 50/48 Input queue high water mark: 1 Input queue depth: 0 Total packets sent: 1100 Total packets received: 1043 Based on this output, what can be concluded?

A.The router has experienced many route flaps.
B.The network is stable with few topology changes.
C.The router is using EIGRP stub to suppress queries.
D.There is a high packet loss on the network.
AnswerB

Low query and reply counts indicate stable topology.

Why this answer

The output shows a very low number of EIGRP Queries (2 sent, 3 received) and Replies (3 sent, 2 received), which indicates that the network has experienced very few topology changes. A stable EIGRP network with minimal route flaps will have a high ratio of Hellos to Updates/Queries, as seen here (1000 Hellos vs. 45 Updates). Therefore, the network is stable with few topology changes, making option B correct.

Exam trap

Cisco often tests the misconception that a high number of Hellos indicates instability or that a small difference between sent and received packets automatically means packet loss, when in fact EIGRP Hellos are sent unreliably (multicast) and may be lost without retransmission, so a small discrepancy is normal.

How to eliminate wrong answers

Option A is wrong because route flaps would generate a high number of Updates and Queries, but the output shows only 45 Updates sent and 2 Queries sent, which is very low. Option C is wrong because the output does not show any evidence of EIGRP stub configuration; stub routers suppress queries entirely, but here queries are still being sent and received (2 sent, 3 received), indicating stub is not in use. Option D is wrong because packet loss would be reflected in a mismatch between sent and received packets (e.g., Hellos sent 1000 vs. received 950 is a 5% difference, which is normal for EIGRP due to timing and multicast delivery, not indicative of high loss; total sent 1100 vs. received 1043 is a 5.2% difference, which is typical in a healthy network).

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41
Drag & Dropmedium

Drag and drop the steps of EIGRP route summarization configuration into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

EIGRP route summarization first requires enabling EIGRP, configuring the network statement, then entering interface configuration mode, applying the summary-address command, and finally verifying the summary route in the routing table.

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42
MCQhard

A network engineer runs the following command on Router R1: R1# show ip eigrp topology 10.1.1.0/24 EIGRP-IPv4 Topology Entry for AS(100)/ID(192.168.1.1) for 10.1.1.0/24 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: (128256/0), Route is Internal Vector metric: Minimum bandwidth: 1000000 Kbit Total delay: 100 microseconds Reliability: 255/255 Load: 1/255 Minimum MTU: 1500 Hop count: 0 192.168.1.2 (GigabitEthernet0/0), from 192.168.1.2, Send flag: 0x0 Composite metric: (1310720/128256), Route is Internal Vector metric: Minimum bandwidth: 1000000 Kbit Total delay: 1100 microseconds Reliability: 255/255 Load: 1/255 Minimum MTU: 1500 Hop count: 1 Based on this output, what can be concluded?

A.The route 10.1.1.0/24 is learned from neighbor 192.168.1.2 and is the successor.
B.The router has a feasible successor for this route.
C.The route is directly connected on Router R1.
D.The router is in Active state for this route.
AnswerC

The Null0 entry with metric 128256/0 indicates a connected route.

Why this answer

The presence of a Null0 route in the EIGRP topology table with a composite metric of (128256/0) and a hop count of 0 indicates that Router R1 has a directly connected interface on the 10.1.1.0/24 network. EIGRP automatically installs a summary or connected route to Null0 to prevent routing loops, and the metric (128256/0) with hop count 0 confirms it is locally originated, not learned from a neighbor.

Exam trap

Cisco often tests the misconception that a Null0 route in the EIGRP topology table indicates a summary or redistributed route, when in fact it confirms a directly connected network; candidates mistakenly assume the neighbor route must be the successor because it has a next-hop IP address.

How to eliminate wrong answers

Option A is wrong because the route learned from neighbor 192.168.1.2 has a composite metric of (1310720/128256), which is higher than the Null0 route's metric (128256/0); the successor is the best path, which is the directly connected Null0 route, not the neighbor route. Option B is wrong because a feasible successor requires a reported distance (RD) less than the feasible distance (FD) of the successor; here the only neighbor route has an RD of 128256, which is equal to the FD of the Null0 route (128256), so it does not meet the feasibility condition (RD < FD). Option D is wrong because the output shows 'State: Passive', meaning the router is not performing Diffusing Update Algorithm (DUAL) computations for this route; an Active state would indicate the router is actively querying neighbors for a lost route.

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43
MCQhard

An engineer is troubleshooting an EIGRP issue where a router is not learning a specific route from a neighbor. The engineer runs 'show ip eigrp topology all-links' and sees the route in the topology table with a feasible distance of 100 and a reported distance of 120. The neighbor's advertised distance is 80. The router's own computed distance to the network is 150. The route is not in the routing table. What is the most likely cause?

A.The route is a feasible successor, but the successor route is not present.
B.The route is not installed because the reported distance (80) from the neighbor is less than the feasible distance (100), but the router's computed distance (150) is higher.
C.The route is not installed because the feasible distance (100) is not the best metric; the router has another route with a lower metric.
D.The route is not installed because EIGRP is configured for stub routing, which prevents learning routes.
AnswerC

Correct. The feasible distance is 100, but if there is another route with a lower metric (e.g., 90), that route would be the successor and installed. The route with FD 100 would not be installed. The scenario implies the route is not the best.

Why this answer

Option C is correct because EIGRP installs the route with the best feasible distance (FD) into the routing table. The router's computed distance of 150 is lower than the feasible distance of 100, meaning the router has a better path (FD 100) already in the topology table. Since the route is not in the routing table, the router must have another route with a lower metric (FD 100) that is already installed, and the route with FD 150 is not selected as the successor.

Exam trap

Cisco often tests the distinction between the feasible distance (FD) and the computed distance (also called the metric) — candidates confuse the reported distance (RD) with the router's own computed distance, thinking that a lower RD automatically means the route is installed, but EIGRP installs only the route with the lowest FD, not the lowest RD.

How to eliminate wrong answers

Option A is wrong because a feasible successor is a backup route that meets the feasibility condition (reported distance < feasible distance), but the route is not installed as a feasible successor if the successor route is present; the issue is that the route is not in the routing table, not that the successor is missing. Option B is wrong because the reported distance (80) from the neighbor is less than the feasible distance (100), which actually satisfies the feasibility condition, but the router's computed distance (150) being higher than the FD (100) means this route is not the best path; the route is not installed because the router has a better path (FD 100), not because of the reported distance comparison. Option D is wrong because stub routing prevents the router from learning routes from neighbors, but the router is learning the route (it appears in the topology table), so stub routing is not the cause; the issue is about route selection, not route learning.

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44
MCQmedium

Consider the following EIGRP configuration: router eigrp 100 metric weights 0 1 0 1 0 0 What does this configuration accomplish?

A.It sets the EIGRP metric to use bandwidth and delay only, which is the default behavior.
B.It disables the use of bandwidth in the metric calculation.
C.It enables the use of load and reliability in the metric calculation.
D.It changes the metric to use only delay.
AnswerA

Correct. The default K values are k1=1, k2=0, k3=1, k4=0, k5=0, so this command explicitly sets them to the default.

Why this answer

The `metric weights` command in EIGRP allows you to modify the K values used in the composite metric calculation. The default K values are K1=1, K2=0, K3=1, K4=0, K5=0, which means only bandwidth (K1) and delay (K3) are used. The configuration `metric weights 0 1 0 1 0 0` explicitly sets K1=1, K2=0, K3=1, K4=0, K5=0, which matches the default behavior.

Therefore, option A is correct.

Exam trap

Cisco often tests the misconception that the `metric weights` command changes the metric calculation from the default, when in fact the given values exactly match the default K values (1,0,1,0,0).

How to eliminate wrong answers

Option B is wrong because the configuration sets K1=1, which enables the use of bandwidth in the metric calculation, not disables it. Option C is wrong because the configuration sets K2=0 and K4=0, which disables load and reliability, respectively; enabling them would require K2=1 and K4=1. Option D is wrong because the configuration sets K1=1, so bandwidth is still included; to use only delay, you would need K1=0 and K3=1.

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45
Matchingmedium

Drag and drop each EIGRP DUAL state on the left to its matching stage on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Route is stable and no queries are pending

Router is querying neighbors for a new route

Router uses a feasible successor without querying

Router queries all neighbors for a new route

Router that first sends a query for a lost route

Why these pairings

Passive state indicates a stable route; Active state indicates the router is querying neighbors; Local Computation occurs when a feasible successor exists; Diffusing Computation occurs when no feasible successor exists; Query Origin is the router that starts the query process.

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46
Drag & Dropmedium

Drag and drop the steps of EIGRP neighbor establishment into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

EIGRP neighbor formation begins with sending Hello packets, then exchanging full routing tables via Update packets, acknowledging with ACK packets, and finally entering the Established state where incremental updates are sent.

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47
Multi-Selectmedium

Which two statements about EIGRP feasible successors are true? (Choose two.)

Select 2 answers
A.A feasible successor must have a reported distance less than the feasible distance of the current successor.
B.A feasible successor is installed in the routing table as a backup route.
C.If a successor fails, EIGPR immediately uses a feasible successor without transitioning to active state.
D.The feasible successor must have the same metric as the successor.
E.EIGRP uses the Diffusing Update Algorithm (DUAL) to determine feasible successors.
AnswersA, C

Correct because the feasibility condition requires RD < FD for a route to be considered a feasible successor.

Why this answer

A feasible successor is a backup route that meets the feasibility condition (reported distance < feasible distance). It is stored in the topology table, not the routing table, and is used immediately if the successor fails.

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48
Multi-Selecthard

Which three statements about EIGRP route summarization are true? (Choose three.)

Select 3 answers
A.Manual summarization is configured using the 'ip summary-address eigrp <as> <prefix> <mask>' command on an interface.
B.Automatic summarization is enabled by default in EIGRP for IPv4.
C.A manual summary route is advertised with a metric equal to the best metric among the component routes.
D.Summary routes are always preferred over more specific routes in the routing table.
E.EIGRP will install a discard route (null0) for the summary prefix to prevent routing loops.
AnswersA, C, E

Correct because this is the standard command to configure a manual summary route on a specific interface.

Why this answer

EIGRP supports manual summarization on any interface and automatic summarization at classful boundaries (disabled by default in modern IOS). Summary routes are advertised with a metric based on the component routes.

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49
Matchingmedium

Drag and drop each EIGRP state on the left to its matching DUAL stage on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Route is stable and no DUAL computation is in progress

DUAL is actively querying neighbors for an alternate path

Query has not been replied to within the active timer

Router sends queries to all neighbors for a lost route

Router has received all replies to its queries

Why these pairings

Passive is the stable state; Active is when DUAL is actively searching for a new route; Stuck in Active occurs when a query is not answered within the active timer.

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50
Matchingmedium

Drag and drop each EIGRP packet type on the left to its matching function on the right.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Discovers and maintains neighbors

Carries routing information

Asks for successor information

Responds to a query

Acknowledges receipt of a reliable packet

Why these pairings

Hello packets discover and maintain neighbors; Update packets carry routing information; Query packets ask for successor information; Reply packets respond to queries; ACK packets acknowledge reliable packets.

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51
Multi-Selectmedium

Which two statements about EIGRP stub routing are true? (Choose two.)

Select 2 answers
A.A stub router advertises only connected and summary routes by default.
B.A stub router can still be used as a transit router for other EIGRP neighbors.
C.The 'eigrp stub' command is configured on the hub router in a hub-and-spoke topology.
D.EIGRP stub routing reduces query scoping and improves convergence.
E.A stub router can be configured with the 'receive-only' keyword to advertise all its routes.
AnswersA, D

Correct because the default stub setting (without keywords) advertises connected and summary routes.

Why this answer

EIGRP stub routing limits the routes a stub router advertises, preventing it from being used as a transit router. Common stub types include connected, static, summary, and receive-only.

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52
MCQmedium

Which of the following is used by EIGRP to calculate the feasible distance (FD) of a route?

A.The sum of the advertised distance (AD) of the successor and the link cost to the successor.
B.The lowest hop count among all paths to the destination.
C.The highest bandwidth among all paths to the destination.
D.The sum of all delays along the path.
AnswerA

Correct. The feasible distance is the metric of the successor, which is the AD (reported distance from neighbor) plus the link cost to that neighbor.

Why this answer

EIGRP calculates the Feasible Distance (FD) as the sum of the Advertised Distance (AD) from the successor neighbor and the link cost (metric) to that neighbor. This represents the total metric from the local router to the destination network via that path. The FD is used to determine the best route (successor) and to compare against feasible successors.

Exam trap

Cisco often tests the distinction between Feasible Distance (FD) and Advertised Distance (AD), and the trap here is that candidates confuse FD with just the link cost or one metric component (like delay or bandwidth), rather than recognizing it as the sum of the AD and the cost to the successor.

How to eliminate wrong answers

Option B is wrong because EIGRP does not use hop count for metric calculation; it uses a composite metric based on bandwidth, delay, load, and reliability (by default bandwidth and delay). Option C is wrong because while bandwidth is a component of the EIGRP metric, the FD is not simply the highest bandwidth; it is a calculated value using the composite metric formula. Option D is wrong because delay is only one component of the EIGRP metric, and the FD is not the sum of all delays along the path; it is the sum of the AD and the link cost, which itself is derived from the composite metric.

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53
Drag & Dropmedium

Drag and drop the steps of EIGRP redistribution from OSPF with metric seeding into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

First, the EIGRP routing process must be entered. Then, the redistribute command is used with the OSPF process and a metric. Optionally, route-map filtering can be applied.

Finally, verification ensures routes appear in the EIGRP topology table.

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54
MCQmedium

Examine the following EIGRP configuration snippet: interface GigabitEthernet0/0 ip bandwidth-percent eigrp 100 50 What is the effect of this command?

A.EIGRP will use up to 50% of the interface bandwidth for its control traffic.
B.EIGRP will only advertise routes that have a metric within 50% of the best path.
C.EIGRP will use 50% of the interface bandwidth for data traffic.
D.EIGRP will reduce its hello interval by 50%.
AnswerA

Correct. This command limits EIGRP's bandwidth usage to 50% of the interface's configured bandwidth.

Why this answer

The `ip bandwidth-percent eigrp 100 50` command configures EIGRP to use up to 50% of the interface's configured bandwidth for its control traffic (hello, update, query, and reply packets). This limits the amount of bandwidth EIGRP can consume to prevent it from starving other traffic. The percentage is applied to the interface's `bandwidth` setting, not the actual physical link speed.

Exam trap

Cisco often tests the misconception that `ip bandwidth-percent eigrp` controls data traffic or route selection, when in fact it only limits EIGRP's own control plane bandwidth usage.

How to eliminate wrong answers

Option B is wrong because EIGRP does not have a mechanism to advertise only routes within a percentage of the best path; variance and offset-lists are used for unequal-cost load balancing, not route filtering based on metric percentage. Option C is wrong because this command specifically limits EIGRP control traffic, not data traffic; data traffic is unaffected by this command. Option D is wrong because the `ip bandwidth-percent eigrp` command does not influence the hello interval; hello intervals are configured separately with `ip hello-interval eigrp`.

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55
MCQhard

A network engineer is configuring EIGRP on a router that connects to a service provider network. The engineer wants to advertise a default route to internal routers. The engineer configures 'ip default-network 0.0.0.0' and redistributes a static default route into EIGRP. However, internal routers are not receiving the default route. The engineer checks the EIGRP topology table and sees the default route with a metric of 1. What is the most likely reason?

A.The engineer used 'ip default-network' which is not supported in EIGRP; instead, 'default-information originate' should be used.
B.The static default route is not configured correctly; the engineer should use 'ip route 0.0.0.0 0.0.0.0 <next-hop>'.
C.The internal routers have a route to the default network with a better metric from another source.
D.The engineer needs to configure 'eigrp stub' on the router to allow default route advertisement.
AnswerA

Correct. EIGRP does not support the 'ip default-network' command. To advertise a default route, the engineer should use 'redistribute static' and optionally 'default-information originate' to inject the default route.

Why this answer

Option A is correct because EIGRP does not support the 'ip default-network' command to originate a default route; this command is used with IGRP. To advertise a default route in EIGRP, the engineer must use the 'default-information originate' command under the EIGRP process, which redistributes a static default route (0.0.0.0/0) into EIGRP. The presence of the default route in the topology table with a metric of 1 indicates it was redistributed, but without 'default-information originate', EIGRP will not advertise it to neighbors.

Exam trap

Cisco often tests the misconception that 'ip default-network' works with EIGRP, when in fact it is an IGRP-specific command, and candidates may confuse it with the correct 'default-information originate' command used in EIGRP and OSPF.

How to eliminate wrong answers

Option B is wrong because the static route syntax 'ip route 0.0.0.0 0.0.0.0 <next-hop>' is correct and commonly used; the issue is not with the static route configuration but with the EIGRP advertisement method. Option C is wrong because the topology table shows the default route with a metric of 1, and if internal routers had a better metric from another source, the route would still be present in the topology table but not selected as best; the problem is that the route is not being advertised at all. Option D is wrong because configuring 'eigrp stub' restricts the router from advertising routes learned from other EIGRP neighbors, but it does not prevent the advertisement of a locally originated default route via 'default-information originate'; the stub feature is used to limit route propagation, not to enable default route advertisement.

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56
Drag & Dropmedium

Drag and drop the steps of EIGRP variance-based unequal-cost load balancing into the correct order, from first to last.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4
5Step 5

Why this order

First, the EIGRP process must be configured. Then, the variance multiplier is set to allow feasible successors with higher metrics. Optionally, the maximum-paths command can increase the number of paths.

Finally, verification confirms multiple routes in the routing table.

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57
MCQmedium

Given the following EIGRP configuration on a router: router eigrp 200 network 192.168.1.0 0.0.0.255 network 10.0.0.0 Which statement about this configuration is true?

A.EIGRP will be enabled on any interface with an IP address in the 10.0.0.0/8 range, and only on interfaces with an IP address in the 192.168.1.0/24 range.
B.Both network statements are classful and will enable EIGRP on all interfaces with IP addresses in the 192.168.0.0/16 and 10.0.0.0/8 ranges.
C.EIGRP will only be enabled on interfaces with an IP address in the 192.168.1.0/24 range.
D.This configuration will cause an error because wildcard masks are not allowed in EIGRP network statements.
AnswerA

Correct. The first network statement uses a wildcard mask to specify the exact subnet, while the second is classful.

Why this answer

Option A is correct because the first network statement uses a wildcard mask (0.0.0.255) to enable EIGRP only on interfaces in the 192.168.1.0/24 subnet, while the second network statement (10.0.0.0) is classful and enables EIGRP on all interfaces in the 10.0.0.0/8 range. EIGRP network statements can include a wildcard mask to specify a subnet; without one, the router assumes the classful boundary.

Exam trap

Cisco often tests the distinction between classful and classless network statements in EIGRP, where candidates mistakenly assume that a network statement without a wildcard mask applies only to the exact subnet rather than the entire classful range.

How to eliminate wrong answers

Option B is wrong because the first network statement uses a wildcard mask (0.0.0.255), which restricts EIGRP to the 192.168.1.0/24 subnet, not the classful 192.168.0.0/16 range. Option C is wrong because the second network statement (10.0.0.0) is classful and enables EIGRP on all interfaces in the 10.0.0.0/8 range, not just the 192.168.1.0/24 subnet. Option D is wrong because EIGRP explicitly supports wildcard masks in network statements (e.g., network 192.168.1.0 0.0.0.255) to allow subnet-level granularity.

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58
MCQmedium

A network engineer runs the following command on Router R1: R1# debug eigrp packets hello EIGRP: Received HELLO on Gi0/0 nbr 192.168.1.2 AS 100, Flags 0x0, Seq 0/0 interfaceQ 0/0 EIGRP: Sending HELLO on Gi0/0 AS 100, Flags 0x0, Seq 0/0 interfaceQ 0/0 EIGRP: Received HELLO on Gi0/1 nbr 10.1.1.2 AS 100, Flags 0x0, Seq 0/0 interfaceQ 0/0 EIGRP: Sending HELLO on Gi0/1 AS 100, Flags 0x0, Seq 0/0 interfaceQ 0/0 Based on this output, what can be concluded?

A.EIGRP is using MD5 authentication between neighbors.
B.The hello packets are being exchanged normally without any issues.
C.There is a K-value mismatch between R1 and its neighbors.
D.The router is using EIGRP named mode.
AnswerB

The debug shows consistent sending and receiving of hellos with no errors.

Why this answer

The debug output shows EIGRP hello packets being sent and received on both interfaces without any errors, sequence mismatches, or authentication failures. The 'Flags 0x0' and 'Seq 0/0' indicate normal operation, and the neighbor IPs are present, confirming that the EIGRP adjacency is forming correctly. Therefore, the hello packets are being exchanged normally without any issues.

Exam trap

Cisco often tests the distinction between normal hello exchange and authentication or parameter mismatch by showing clean debug output with 'Flags 0x0' and 'Seq 0/0', leading candidates to incorrectly assume authentication is present or that a mismatch exists.

How to eliminate wrong answers

Option A is wrong because the debug output shows 'Flags 0x0' and no authentication-related fields (such as Auth type or key ID), and EIGRP MD5 authentication would include a non-zero authentication field in the packet. Option C is wrong because a K-value mismatch would prevent neighbor adjacency formation, but the debug shows successful hello exchange and neighbor IPs, indicating no mismatch. Option D is wrong because EIGRP named mode uses different debug output formats (e.g., 'EIGRP-IPv4' or 'EIGRP-IPv6' prefixes) and the classic 'debug eigrp packets' command is used here, which is typical for classic EIGRP configuration.

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