EIGRP Troubleshooting

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

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?

Examine the following EIGRP configuration on Router R3: interface GigabitEthernet0/1 ip bandwidth-percent eigrp 100 50 What is the effect of this command?

Consider the following EIGRP configuration on Router R4: router eigrp 300 variance 2 network 172.16.0.0 What is the purpose of the variance command?

Given the following configuration snippet on Router R5: router eigrp 400 network 10.1.1.0 0.0.0.255 What is wrong with this configuration?

Examine the following EIGRP configuration on Router R6: interface GigabitEthernet0/2 ip hello-interval eigrp 100 15 ip hold-time eigrp 100 45 What is the effect of these commands?

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

Which of the following is a mandatory condition for a route to be considered a feasible successor in EIGRP?

What is the default administrative distance for internal EIGRP routes?

Which TWO commands would a network engineer use to verify that EIGRP is correctly forming neighbor adjacencies and exchanging routes on an interface? (Choose TWO.)

Which TWO statements about EIGRP stub routing are true when troubleshooting a hub-and-spoke topology? (Choose TWO.)

Which TWO configuration steps are required to enable EIGRP authentication between two directly connected routers? (Choose TWO.)

Which THREE symptoms indicate that EIGRP is experiencing a neighbor relationship issue due to an MTU mismatch? (Choose THREE.)

Which TWO commands can be used to troubleshoot EIGRP route redistribution issues when routes are not appearing in the routing table? (Choose TWO.)

An enterprise network uses EIGRP with route summarization. Router R1 has the following configuration: interface GigabitEthernet0/0 ip summary-address eigrp 100 10.1.0.0 255.255.252.0. Router R2, connected to R1 via GigabitEthernet0/0, shows: 'show ip route eigrp' includes 10.1.0.0/22 but not the more specific route 10.1.1.0/24. Hosts in subnet 10.1.1.0/24 are unreachable from R2. What is the root cause?

A network redistributes EIGRP into OSPF. Router R1 is a redistribution point with configuration: router eigrp 100 redistribute ospf 1 metric 10000 100 255 1 1500. Router R2, an OSPF router, shows: 'show ip route ospf' includes some EIGRP routes but with higher cost than expected. Traffic from R2 to those networks takes suboptimal paths. What is the root cause?

A BGP-speaking router R1 is redistributing BGP routes into EIGRP. R1 has configuration: router bgp 100 redistribute eigrp 100. Router R2, an EIGRP neighbor, shows: 'show ip route eigrp' includes some BGP routes but with high metrics. Traffic to those destinations is suboptimal. What is the root cause?

An OSPF network has a multi-access link between routers R1 and R2. R1 is configured with 'ip ospf network point-to-point' on the interface, while R2 uses the default broadcast network type. R1 shows: 'show ip ospf neighbor' lists R2 as FULL/DR, but R2 shows: 'show ip ospf neighbor' lists R1 as FULL/DROTHER. Traffic from R1 to R2's loopback is fine, but from R2 to R1's loopback is intermittent. What is the root cause?

An EIGRP network is experiencing frequent stuck-in-active (SIA) events. Router R1 shows: 'show ip eigrp topology' includes routes in active state for several minutes. R1's configuration: router eigrp 100 timers active-time 3. R2, a neighbor, is reachable but has a large number of routes. What is the root cause?

A DMVPN network with EIGRP as the routing protocol is experiencing spoke-to-spoke tunnel failures. Spoke routers R1 and R2 are both connected to hub R3. R1 shows: 'show ip nhrp' lists R2's NBMA address, but 'show ip eigrp neighbors' does not show R2. R1's configuration: interface Tunnel0 ip nhrp network-id 1 ip nhrp nhs 10.0.0.3. What is the root cause?

An MPLS network with EIGRP as the IGP is experiencing label distribution failures. Router R1 shows: 'show mpls ldp neighbor' does not list R2. R1's configuration: mpls ip on interfaces, but no router-id configured. R2's configuration: mpls ldp router-id Loopback0 force. R1 and R2 are directly connected. What is the root cause?

A network uses ACLs to filter traffic. Router R1 has the following ACL applied to interface GigabitEthernet0/0 in the inbound direction: access-list 100 permit tcp any any eq 22. Router R2, connected to R1, cannot SSH to R1's loopback address. R1 shows: 'show ip interface GigabitEthernet0/0' indicates the ACL is applied. What is the root cause?

A network uses Control Plane Policing (CoPP) to protect the router. Router R1 has CoPP policy applied that rate-limits all traffic to 1 Mbps. R1 shows: 'show policy-map control-plane' indicates drops for EIGRP packets. R1's EIGRP neighbor R2 is flapping. What is the root cause?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# debug eigrp packets hello *Mar 1 00:05:23.123: EIGRP: received packet with MD5 authentication, key id = 1 *Mar 1 00:05:23.123: EIGRP: int GigabitEthernet0/0, src 10.1.1.2 dst 224.0.0.10, seq 0, ttl 1, opcode = 1 (Hello) *Mar 1 00:05:23.123: EIGRP: authentication failed for packet from 10.1.1.2, key id = 1, integrity check failed What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# show ip eigrp topology 10.1.1.0/24 IP-EIGRP (AS 100): Topology entry for 10.1.1.0/24 State: Passive, Query origin flag: 1, 1 Successor(s), FD is 131072 Routing Descriptor Blocks: 10.1.2.2 (GigabitEthernet0/0), from 10.1.2.2, Send flag: 0x0 Composite metric: (131072/130816), Route is Internal Vector metric: Minimum bandwidth is 10000 Kbit Total delay is 100 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 10.1.3.3 (GigabitEthernet0/1), from 10.1.3.3, Send flag: 0x0 Composite metric: (131328/131072), Route is Internal Vector metric: Minimum bandwidth is 10000 Kbit Total delay is 200 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 2 What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# show ip eigrp topology all-links IP-EIGRP Topology Table for AS 100 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 131072 via 10.1.2.2 (131072/130816), GigabitEthernet0/0 via 10.1.3.3 (131328/131072), GigabitEthernet0/1 P 10.2.2.0/24, 1 successors, FD is 131072 via 10.1.2.2 (131072/130816), GigabitEthernet0/0 A 10.3.3.0/24, 0 successors, FD is Infinity via 10.1.2.2 (4294967295/4294967295), GigabitEthernet0/0 via 10.1.3.3 (4294967295/4294967295), GigabitEthernet0/1 What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# show ip eigrp neighbors detail IP-EIGRP neighbors for process 100 H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 0 10.1.2.2 Gi0/0 13 00:12:34 12 200 0 145 Version 12.4/1.2, Retrans: 0, Retries: 0, Prefixes: 5 Topology-ids from peer - 0 Stub Peer Advertising (CONNECTED STATIC) Routes Suppressing queries What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# debug eigrp packets update *Mar 1 00:10:15.456: EIGRP: received packet with opcode = 2 (Update) on GigabitEthernet0/0, src 10.1.2.2 dst 10.1.2.1 *Mar 1 00:10:15.456: EIGRP: Update contains 5 routes, version 145, seq 10 *Mar 1 00:10:15.456: EIGRP: Update update/interval, 10.1.1.0/24 metric 131072 *Mar 1 00:10:15.456: EIGRP: Update update/interval, 10.2.2.0/24 metric 131072 *Mar 1 00:10:15.456: EIGRP: Update update/interval, 10.3.3.0/24 metric 131072 *Mar 1 00:10:15.456: EIGRP: Update update/interval, 10.4.4.0/24 metric 131072 *Mar 1 00:10:15.456: EIGRP: Update update/interval, 10.5.5.0/24 metric 131072 What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# show ip eigrp interfaces detail Interface GigabitEthernet0/0 EIGRP interface state: Enabled, Up Hello interval: 5 sec, Hold time: 15 sec Split horizon: Enabled Next multicast: 0.0.0.0, Next update: 0.0.0.0 Bandwidth: 10000 Kbit, Delay: 100 us Reliability: 255/255, Load: 1/255, MTU: 1500 Packets sent: 100, received: 95 Authentication: MD5, key chain: EIGRP-KEY Passive interface: No What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# show ip eigrp traffic IP-EIGRP Traffic Statistics for process 100 Hellos sent/received: 500/495 Updates sent/received: 10/8 Queries sent/received: 2/1 Replies sent/received: 1/2 Acks sent/received: 8/10 Input queue high water mark: 2, Input queue depth: 0 Total packets sent: 521, received: 516 What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# debug eigrp fsm *Mar 1 00:20:45.678: EIGRP: 10.1.1.0/24 - do advertising, metric 131072 *Mar 1 00:20:45.678: EIGRP: 10.1.1.0/24 - route installed in table *Mar 1 00:20:45.678: EIGRP: 10.1.1.0/24 - metric change from 131072 to 131328 *Mar 1 00:20:45.678: EIGRP: 10.1.1.0/24 - find FS, metric 131328, RD 130816 *Mar 1 00:20:45.678: EIGRP: 10.1.1.0/24 - found FS via 10.1.3.3, metric 131328 *Mar 1 00:20:45.678: EIGRP: 10.1.1.0/24 - new successor is 10.1.3.3 What does this output indicate?

A network engineer runs the following command to troubleshoot an EIGRP issue: R1# show ip eigrp topology 10.1.1.0/24 detail IP-EIGRP (AS 100): Topology entry for 10.1.1.0/24 State: Passive, Query origin flag: 1, 1 Successor(s), FD is 131072 Routing Descriptor Blocks: 10.1.2.2 (GigabitEthernet0/0), from 10.1.2.2, Send flag: 0x0 Composite metric: (131072/130816), Route is Internal Vector metric: Minimum bandwidth is 10000 Kbit Total delay is 100 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 Originating router: 10.1.2.2 External data: Not advertised Protocol: EIGRP Route tag: 0 Extended community: None What does this output indicate?

What is the default EIGRP hello interval on a point-to-point serial interface with bandwidth 1544 Kbps?

Which EIGRP packet type is used to confirm receipt of a reliable update?

What is the default EIGRP hold time multiplier relative to the hello interval?

Which of the following is the correct formula for EIGRP composite metric calculation using default K values?

What is the default behavior of EIGRP auto-summary in IOS-XE 15.x and later?

Which EIGRP loop prevention mechanism prevents a router from installing a route that was originally learned from itself?

What is the default EIGRP authentication mode when authentication is configured?

What is the maximum hop count for an EIGRP route?

Which of the following is the default EIGRP network type on a Frame Relay point-to-point subinterface?

Drag and drop the steps to troubleshoot EIGRP neighbor adjacency formation into the correct order, from first to last.

Drag and drop the steps to troubleshoot EIGRP adjacency or connectivity failures into the correct order, from first to last.

Drag and drop the steps to verify and validate the EIGRP operational state into the correct order, from first to last.

Which TWO statements correctly describe the behavior of EIGRP stub routing and its impact on troubleshooting? (Choose TWO.)

Which TWO actions will prevent an EIGRP neighbor relationship from forming due to authentication mismatch? (Choose TWO.)

An engineer is troubleshooting an EIGRP network where routes from router R1 are not being installed in the routing table of router R2, although R2 sees them in the EIGRP topology table. Which TWO configuration issues could cause this problem? (Choose TWO.)

Which THREE commands can be used to verify and troubleshoot EIGRP route redistribution issues, specifically when routes are not being redistributed correctly? (Choose THREE.)

An engineer is troubleshooting an EIGRP network where some routers are not learning all routes, and suspects a route filtering issue. Which TWO statements about EIGRP route filtering are true? (Choose TWO.)

An engineer configures EIGRP named mode with `address-family ipv4 unicast autonomous-system 100` and applies an offset-list to a neighbor using `offset-list 1 out 1000` under the `af-interface` configuration. Unexpectedly, the offset-list does not affect the feasible distance (FD) as expected, but the advertised distance (AD) is increased. Which is the most likely explanation?

An engineer configures EIGRP stub with `eigrp stub connected static` on a remote router. The remote router has a directly connected network and a static route redistributed into EIGRP. Unexpectedly, the hub router does not receive the static route, although the connected route is learned. Which is the most likely explanation?

Two routers are configured with EIGRP using `network 0.0.0.0 0.0.0.0` to enable EIGRP on all interfaces. One router has a loopback interface with IP 10.1.1.1/32. The other router learns 10.1.1.1/32 via EIGRP. An engineer then configures `distribute-list prefix FILTER out` under the EIGRP process on the first router, where FILTER denies 10.1.1.1/32. Unexpectedly, the second router still receives the route. Which is the most likely explanation?

An engineer configures mutual redistribution between EIGRP and OSPF on a router. EIGRP routes are redistributed into OSPF with a route-map that sets metric-type type-1, and OSPF routes are redistributed into EIGRP with default metric 10000 100 255 1 1500. Unexpectedly, the router starts flapping routes between the two protocols, causing instability. Which is the most likely explanation?

A DMVPN Phase 2 network is configured with EIGRP as the routing protocol over the tunnel interface. Spoke routers have `no ip split-horizon eigrp 100` configured on the tunnel interface. Unexpectedly, spoke-to-spoke tunnels are established, but EIGRP routes learned from one spoke are not installed in the routing table of another spoke, even though NHRP resolution works. Which is the most likely explanation?

An engineer configures IPsec between two routers using a site-to-site VPN with IKEv1. The configuration uses `crypto isakmp policy 10` with authentication pre-share and encryption aes. On the peer, the policy is configured with authentication pre-share and encryption 3des. Unexpectedly, the IKE phase 1 negotiation fails. Which is the most likely explanation?

An engineer configures Control Plane Policing (CoPP) on a router with a policy-map that matches EIGRP packets and sets a police rate of 1000 pps. The class-default is configured with a police rate of 100 pps. Unexpectedly, EIGRP neighbor relationships start flapping, even though the EIGRP packet rate is well below 1000 pps. Which is the most likely explanation?

An engineer enables uRPF (unicast Reverse Path Forwarding) in strict mode on an interface connected to a DMVPN spoke. The spoke has multiple tunnels and receives traffic from the hub with a source IP that is not the best reverse path. Unexpectedly, the spoke drops all traffic from the hub, even though the hub is reachable via the tunnel. Which is the most likely explanation?

Two routers are configured with EIGRP and have a neighbor relationship. One router has a route to 192.168.1.0/24 with metric 100. The other router has a route to the same prefix with metric 200. An engineer configures an offset-list on the first router to increase the metric of 192.168.1.0/24 by 50, expecting the second router to prefer its own route. Unexpectedly, the second router still prefers the first router's route after the offset. Which is the most likely explanation?