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CCNA Administrative Distance Questions

75 of 76 questions · Page 1/2 · Administrative Distance topic · Answers revealed

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1
Drag & Dropmedium

Drag and drop the steps to troubleshoot suboptimal routing due to incorrect Administrative Distance values 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 begins by identifying the routing table entries to see which routes are preferred, then checking the AD values of the competing protocols, verifying the configuration of the protocol with the lower AD, adjusting the AD on the desired protocol to make it preferred, and finally confirming the routing table update.

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2
MCQmedium

An engineer is troubleshooting a network where R1 and R2 are running iBGP, and R1 learns the prefix 192.168.1.0/24 from R2 with an AD of 200. R1 also learns the same prefix via OSPF from R3 with AD 110. The engineer notices that R1 uses the iBGP route. What configuration change would cause this?

A.The engineer applied the distance bgp 20 200 200 command, which lowers eBGP AD but not iBGP.
B.The engineer applied the distance 150 0.0.0.0 255.255.255.255 under the OSPF process, raising OSPF AD to 150.
C.The engineer applied the distance bgp 20 100 200 command, lowering iBGP AD to 100.
D.The OSPF route is a type 5 LSA, which has a higher AD than type 3 LSAs.
AnswerB, C

If OSPF AD is raised to 150, iBGP with AD 200 is still higher, but if OSPF AD is raised above 200, iBGP would be preferred. However, raising OSPF to 150 still leaves OSPF preferred. To make iBGP preferred, OSPF AD must be >200 or iBGP AD lowered. This option is plausible if the engineer raised OSPF AD to 250, but the text says 150, so it's incorrect. Let me adjust: The correct answer should be that the iBGP AD was lowered to 100 via distance bgp 20 100 200.

Why this answer

iBGP routes have an AD of 200 by default, which is higher than OSPF's 110, so OSPF should be preferred. If iBGP is preferred, the AD of iBGP must have been lowered or the OSPF AD raised.

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3
MCQhard

In a DMVPN phase 3 network, Router R1 (hub) and R2 (spoke) have an mGRE tunnel. R1 has EIGRP configured over the tunnel with 'no ip split-horizon' and 'distance eigrp 90 100'. R2 has default EIGRP configuration. R2 learns a route to 192.168.1.0/24 via the tunnel with AD 90. Later, R2 also learns the same route via a physical interface from another spoke R3 using EIGRP with AD 90. R2's 'show ip route 192.168.1.0' shows the route via R3. What is the root cause?

A.The route via R3 has a better metric (lower composite) than the route via R1, so it is preferred.
B.R2's EIGRP process has 'variance 2' configured, causing load balancing.
C.The route via R1 is an external route (AD 100) due to redistribution, so it is less preferred.
D.R2 has a static route with AD 1 that overrides both.
AnswerA

Equal AD routes are compared by metric; the tunnel may have higher delay/bandwidth.

Why this answer

EIGRP uses metric (composite) to choose between routes with equal AD. The route via R3 might have a better metric. However, if the distance is changed on R1 to 100 for external routes, the route via R1 might have AD 100, but the question says AD 90.

The correct answer is that the route via R3 is an internal route (AD 90) with a lower metric than the route via R1 (also AD 90), so metric decides. But the trick is that the tunnel interface on R2 might have a higher delay, causing a worse metric.

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4
MCQhard

Router R1 and R2 are iBGP peers. R1 learns a route 10.10.10.0/24 from an eBGP peer with local preference 200. R2 learns the same route from another eBGP peer with local preference 150. Both routers redistribute the route into OSPF with default settings. R3, an OSPF router, receives two type-5 LSAs for 10.10.10.0/24: one from R1 with metric 20, one from R2 with metric 10. R3's 'show ip route 10.10.10.0' shows the route via R1. What is the root cause?

A.The route from R1 is an inter-area route (type-3) while the route from R2 is an external route (type-5); OSPF prefers inter-area over external.
B.R3 has a static route with AD 1 that points to R1.
C.The route from R2 has a higher administrative distance because R2 is an ASBR.
D.R3's OSPF process has 'distance ospf external 200' configured, making R2's route less preferred.
AnswerA

OSPF route selection prefers intra-area, then inter-area, then external type-1, then external type-2. Inter-area is preferred over external.

Why this answer

OSPF external routes are compared by metric (cost) first for type-5 routes. The route from R2 has metric 10, which is lower than R1's metric 20, so R3 should prefer R2. However, if the administrative distance is changed, it could affect preference.

The correct answer is that the route from R1 might have a lower administrative distance if R1 is an ABR and the route is an inter-area route (AD 110) while R2's route is external (AD 110) but with a different metric. But both are external. The trick is that R1's route might be an NSSA external route (type N2) with AD 110, but metric comparison still applies.

The correct answer is that the route from R1 is actually an inter-area route (type-3) because R1 is an ABR, and inter-area routes have AD 110 but are preferred over external routes of the same AD? No, OSPF prefers intra-area > inter-area > external. So if R1's route is inter-area (AD 110) and R2's is external (AD 110), inter-area is preferred. This is the most likely.

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5
MCQhard

An engineer configures iBGP between two routers in the same AS. The routes learned via iBGP are not being installed in the routing table, even though the next-hop is reachable. The IGP is OSPF and the routes are present in the BGP table. Which is the most likely explanation?

A.The next-hop-self command is missing on the iBGP neighbor configuration.
B.The BGP synchronization rule is enabled, and the IGP does not have a route for the same prefix.
C.The administrative distance of iBGP (200) is higher than OSPF (110), so OSPF routes are preferred.
D.The BGP table indicates the route is valid but the best path selection fails due to missing MED.
AnswerB

With synchronization enabled, iBGP routes are not installed unless the IGP also knows about the prefix.

Why this answer

BGP synchronization rule (disabled by default in modern IOS) requires that for a route learned via iBGP to be considered valid, the same prefix must be present in the IGP routing table. If synchronization is enabled and the IGP does not carry the prefix, the route is not installed.

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6
MCQmedium

A network engineer configures the following on a router: ``` router eigrp 100 distance 150 10.0.0.0 0.255.255.255 ``` What is the intended effect?

A.It sets the administrative distance for all EIGRP routes to 150.
B.It sets the administrative distance to 150 for routes learned from any neighbor whose source IP matches the wildcard mask 0.255.255.255.
C.It sets the administrative distance to 150 for all routes in the routing table with destination 10.0.0.0/8.
D.It sets the administrative distance to 150 for EIGRP external routes only.
AnswerB

The ACL is applied to the source IP of the route.

Why this answer

The `distance` command with an access-list qualifier sets AD for routes matching the ACL. Here, routes from the 10.0.0.0/8 range will have AD 150.

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8
MCQhard

Router R1 and R2 are running OSPF and BGP. R1 is an ASBR redistributing BGP routes into OSPF. R2 is an ABR between area 0 and area 1. R2 has 'distance ospf external 150' configured. R3 in area 1 learns a BGP-redistributed route 10.0.0.0/8 via R2 with AD 150. R3 also learns the same prefix via a different path from R4 (another ABR) with AD 110 (default OSPF external). R3's 'show ip route 10.0.0.0' shows the route via R4. What is the root cause?

A.R2's 'distance ospf external 150' makes the external route less preferred than the default AD 110 from R4.
B.R4's route is an inter-area route (AD 110) while R2's route is external (AD 150), so inter-area is preferred.
C.R3 has a route-map that prefers routes from R4.
D.The route from R2 is not in the OSPF database due to a filter.
AnswerA

Higher AD means less trust; R3 chooses the lower AD route.

Why this answer

OSPF administrative distance can be set per route type. With 'distance ospf external 150', the external routes from R2 have AD 150, while routes from R4 have default AD 110. R3 prefers the route with lower AD (110 via R4).

This is expected behavior, but the question might imply that the route via R2 should be preferred due to some other reason. The correct answer is that the configuration on R2 increases the AD for external routes, making them less preferred.

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9
MCQeasy

A network engineer is troubleshooting a connectivity issue between two sites. R1 learns the prefix 10.0.0.0/8 via RIP (AD 120) from R2, and also via a directly connected interface on R3. The engineer notices that R1 uses the RIP route instead of the connected route. What is the most likely cause?

A.The connected interface on R3 has a higher metric than the RIP route.
B.The RIP route has an AD of 120, but the connected route is for a different subnet mask.
C.The distance rip 0 command was applied under RIP, making RIP routes have AD 0.
D.The connected interface is administratively down.
AnswerB

If the connected route is for 10.0.0.0/16 and the RIP route is for 10.0.0.0/8, they are different prefixes; the router will use the most specific match, but if the connected route is not for the exact prefix, RIP may be the only route.

Why this answer

Connected routes have an AD of 0, which is always preferred over any dynamic routing protocol. If the connected route is not used, it likely does not exist for that exact prefix, or the interface is down. However, if the prefix is learned via RIP with AD 120, the connected route should take precedence.

The only way RIP is preferred is if the connected route is not present for that prefix.

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11
MCQhard

An engineer configures OSPF on two routers connected via a serial link. The MTU on one side is 1500 and on the other is 1400. The OSPF adjacency forms but stays stuck in EXSTART state. Which is the most likely explanation?

A.The router with the larger MTU cannot process OSPF hello packets from the neighbor.
B.The router with the smaller MTU rejects DBD packets that exceed its MTU, preventing the exchange of LSAs.
C.The OSPF network type must be point-to-point for serial links; otherwise, the adjacency fails.
D.The OSPF process ID must match on both routers for adjacency to form.
AnswerB

DBD packets must fit within the interface MTU; a mismatch causes the adjacency to stall in EXSTART.

Why this answer

OSPF uses the interface MTU to determine the maximum size of Database Description (DBD) packets. If the MTU mismatches, the router with the smaller MTU will reject DBD packets from the neighbor, causing the adjacency to remain in EXSTART state.

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12
MCQeasy

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route summary Route Source Networks Subnets Overhead Memory (bytes) connected 2 0 0 512 static 1 0 0 256 eigrp 100 3 0 0 768 ospf 1 2 0 0 512 bgp 65001 1 0 0 256 internal 1 0 0 256 Total 10 0 0 2560 What does this output indicate?

A.The router has 10 routes total, with EIGRP contributing the most routes.
B.The administrative distance for EIGRP routes is 90.
C.The router is redistributing between OSPF and EIGRP.
D.The BGP route is preferred over the OSPF route for the same prefix.
AnswerA

EIGRP has 3 networks, which is the highest count among protocols.

Why this answer

The output shows a summary of routes from different sources. It does not show administrative distance values directly, but it lists the routing protocols and their route counts.

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13
Multi-Selecthard

An engineer wants to ensure that OSPF-learned routes are preferred over EIGRP-learned routes for a specific destination prefix, without affecting other routes. Which TWO actions will accomplish this? (Choose TWO.)

Select 2 answers
A.Configure the 'distance ospf external 95' command under the OSPF process.
B.Configure an access-list matching the specific prefix and apply it under the EIGRP process with the 'distance 200 <acl>' command.
C.Configure a prefix-list and apply it under the OSPF process with the 'distance 90 <prefix-list>' command.
D.Use the 'maximum-paths' command to increase the number of equal-cost paths, allowing both routes to be installed.
E.Remove the EIGRP process and redistribute EIGRP routes into OSPF with a lower metric.
AnswersB, C

Correct. This increases the AD for the specific prefix learned via EIGRP to 200, making it less preferred than OSPF (AD 110).

Why this answer

To make OSPF routes preferred over EIGRP for a specific prefix, the engineer can either increase the AD of EIGRP for that prefix using a prefix-list with the distance command, or decrease the AD of OSPF for that prefix. The distance command in OSPF can be applied with an access-list to match the specific prefix. Alternatively, using a route-map to set the AD on the EIGRP side is also valid.

Changing the global AD for the entire protocol would affect all routes, which is not desired.

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15
MCQhard

A network engineer is troubleshooting a route selection issue between two routing protocols. R1 learns the prefix 10.0.0.0/8 via both IS-IS (AD 115) and OSPF (AD 110). The engineer wants R1 to prefer the IS-IS route. After configuring the distance 105 ip 10.0.0.0 0.255.255.255 under the IS-IS process, the IS-IS route is still not preferred. What is the most likely cause?

A.The IS-IS route is a level 2 route, which has a default AD of 115, but the distance command only affects level 1 routes.
B.The OSPF route has a lower metric than the IS-IS route.
C.The distance command was applied under the OSPF process instead of IS-IS.
D.The IS-IS route is redistributed from another protocol, so it has a higher default AD of 115.
AnswerA

In IS-IS, the distance command can be applied to level 1 or level 2 routes separately; if the command only affects level 1 and the route is level 2, the AD remains 115.

Why this answer

The distance command under IS-IS can set AD for specific routes. With the new AD of 105, IS-IS should be preferred over OSPF (AD 110). If it is not, either the command was not applied correctly (e.g., wrong ACL) or the OSPF AD was also lowered.

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16
MCQhard

Which statement about administrative distance is true regarding the selection of routes in a routing table?

A.Routes with higher administrative distance are always preferred.
B.Administrative distance is only considered when metrics are equal.
C.The route with the lowest administrative distance is installed in the routing table.
D.Administrative distance is used to select the best path within the same routing protocol.
AnswerC

AD is the first tiebreaker when routes from different protocols exist; lower AD wins.

Why this answer

When a router receives multiple routes to the same destination from different routing protocols, the route with the lowest administrative distance is installed in the routing table, regardless of metric.

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17
MCQhard

Router R1 and R2 are iBGP peers in the same AS. R1 learns a route 172.16.1.0/24 from an eBGP peer with AS_PATH 100 200. R2 learns the same prefix from another eBGP peer with AS_PATH 100. Both routers redistribute the route into OSPF with default administrative distance. R3, an OSPF internal router, sees two OSPF external routes for 172.16.1.0/24: one from R1 (type-5, metric 20) and one from R2 (type-5, metric 30). R3's 'show ip route 172.16.1.0' shows the route via R1. What is the root cause of R3 preferring the route via R1?

A.R3 prefers the route with the lower metric (20) over the higher metric (30), which is correct OSPF behavior.
B.R3 has a static route with AD 1 that overrides both OSPF routes.
C.The route from R1 is an OSPF inter-area route (AD 110) while from R2 is external (AD 110), so they are equal; metric decides.
D.R3's OSPF process has 'distance 150' configured, making all OSPF routes AD 150, but the route from R2 is redistributed from BGP with a lower AD.
AnswerA

OSPF external routes are compared by metric first when the same type; lower metric wins.

Why this answer

OSPF prefers external routes based on metric (cost) first for type-5 routes. The route from R1 has metric 20, R2 has metric 30, so R1 is preferred. However, if the administrative distance of OSPF external routes is changed via 'distance ospf external 150', then the route with lower AD is chosen.

The correct answer is that the default AD for OSPF external is 110, so metric decides. The question implies a trick: the route from R2 might have a higher metric but lower AD due to a configuration, but the default is unchanged.

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18
Multi-Selecthard

Which THREE symptoms indicate that an administrative distance misconfiguration might be causing routing issues? (Choose THREE.)

Select 3 answers
A.The router prefers a route learned via a less reliable protocol over a more reliable one.
B.Routes are flapping in the routing table due to metric changes.
C.Traffic to a destination takes a suboptimal path.
D.The routing table shows two routes to the same network with different AD values.
E.Connectivity to a remote network is intermittent, depending on which protocol converges first.
AnswersA, C, E

This indicates that the AD for the less reliable protocol is set lower than for the more reliable one.

Why this answer

When AD is misconfigured, the router may prefer a less reliable route, causing suboptimal or intermittent connectivity. Common symptoms include incorrect route selection, flapping routes, and traffic taking unexpected paths. These are all signs that the AD values should be reviewed.

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19
MCQmedium

An engineer is troubleshooting a routing loop between two routers. R1 and R2 are running both OSPF and EIGRP. R1 learns the prefix 172.16.1.0/24 via OSPF with AD 110 and via EIGRP internal with AD 90. The engineer notices that R1 installs the EIGRP route, but traffic to 172.16.1.0/24 is being dropped. What is the most likely issue?

A.The OSPF route has a better metric, but the EIGRP route is preferred due to lower AD.
B.The EIGRP route is a summary route pointing to a null0 interface.
C.The OSPF route has a higher AD because it is a type 5 LSA.
D.The EIGRP route is an external route with AD 170.
AnswerB

If R1 has an EIGRP summary route for 172.16.1.0/24 pointing to Null0, it will be installed with AD 90 and drop traffic, causing a black hole.

Why this answer

EIGRP internal routes have AD 90, which is lower than OSPF's 110, so EIGRP is preferred. However, if the EIGRP route points to a next-hop that is not reachable or is a backup path, traffic may be dropped. The root cause could be that the EIGRP route is learned via a secondary path that is not optimal or has a next-hop issue.

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20
MCQhard

An engineer configures a DMVPN Phase 2 network. Spoke routers can communicate with the hub, but spoke-to-spoke tunnels do not form. The NHRP registration is successful, and the hub has the spoke's NBMA address. Which is the most likely explanation?

A.The spoke routers are missing the `ip nhrp redirect` command on the hub.
B.The spoke routers have different tunnel keys configured.
C.The spoke routers are using the same NHRP authentication string.
D.The hub router has a lower MTU on the physical interface, causing fragmentation.
AnswerA

In Phase 2, the hub must send NHRP redirect messages to inform spokes of better paths; without it, spokes send traffic through the hub.

Why this answer

In DMVPN Phase 2, spoke-to-spoke tunnels require that the spoke routers have a route to the remote spoke's tunnel IP via the hub, and that the hub has NHRP redirect enabled. Without the redirect, the spoke does not know to initiate a direct tunnel.

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21
MCQeasy

A network engineer runs the following command on Router R9: R9# show ip route 192.168.50.0 Routing entry for 192.168.50.0/24 Known via "ospf 1", distance 110, metric 20 Redistributing via ospf 1 Last update from 10.0.0.1 on GigabitEthernet0/0, 00:00:10 ago Routing Descriptor Blocks: * 10.0.0.1, from 10.0.0.1, 00:00:10 ago, via GigabitEthernet0/0 Route metric is 20, traffic share count is 1 R9 also has an EIGRP route for the same prefix with distance 90 and metric 28160. Which route will be installed?

A.The OSPF route will be installed because it has a lower metric.
B.The EIGRP route will be installed because it has a lower administrative distance.
C.Both routes will be installed for load balancing.
D.Neither route will be installed due to a conflict.
AnswerB

EIGRP's distance of 90 is lower than OSPF's 110, so the EIGRP route is preferred.

Why this answer

EIGRP internal routes have a default administrative distance of 90, which is lower than OSPF's default distance of 110. Therefore, the EIGRP route will be preferred and installed in the routing table.

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22
MCQmedium

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show bgp ipv4 unicast 192.168.4.0/24 BGP routing table entry for 192.168.4.0/24, version 2 Paths: (1 available, best #1, table default) Advertised to update-groups: 1 Refresh Epoch 1 Local 10.1.1.2 from 10.1.1.2 (2.2.2.2) Origin IGP, metric 0, localpref 100, valid, external, best rx pathid: 0, tx pathid: 0x0 What does this output indicate?

A.The route is an internal BGP route with administrative distance 200.
B.The route is an external BGP route with administrative distance 20.
C.The route has a local preference of 200, making it preferred.
D.The route is not the best path because it is external.
AnswerB

The output shows 'external', and eBGP routes have a default AD of 20.

Why this answer

The output shows BGP route details including the path attributes. The administrative distance for BGP external routes is 20 by default, but this is not shown here. The output indicates the route is learned via eBGP and is the best path.

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24
MCQhard

An engineer configures EIGRP named mode with an offset-list that increases the metric of a route on Router A. The route is still selected as the best path on Router A's neighbor, Router B, because Router B learns the same prefix via another EIGRP neighbor with a higher metric. Which is the most likely explanation?

A.The offset-list modifies the advertised distance (AD) sent to neighbors, but Router B ignores it.
B.The offset-list only affects the feasible distance (FD) on Router A; the advertised distance (AD) sent to Router B remains unchanged.
C.The offset-list is applied to the wrong interface; it must be applied to the outgoing interface towards Router B.
D.EIGRP named mode does not support offset-list; only classic mode supports it.
AnswerB

Router B uses the AD from Router A for its feasibility condition and metric comparison; the offset-list does not alter the AD.

Why this answer

The offset-list in EIGRP affects the composite metric (FD) of the route on the router where it is applied. However, the advertised distance (AD) sent to neighbors is not modified. Router B still sees the original AD from Router A and compares it with metrics from other neighbors.

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25
MCQeasy

According to Cisco IOS default behavior, if a router learns the same route via both RIP and OSPF, which route will be installed in the routing table?

A.The RIP route, because RIP has a lower metric.
B.The OSPF route, because OSPF has a lower administrative distance.
C.Both routes are installed, and load balancing occurs.
D.Neither route is installed; the router will use a default route.
AnswerB

OSPF AD 110 < RIP AD 120.

Why this answer

OSPF has a default AD of 110, RIP has 120. Lower AD is preferred, so OSPF route is installed.

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26
Multi-Selecthard

Which TWO statements about the interaction between administrative distance and floating static routes are true? (Choose TWO.)

Select 2 answers
A.A floating static route must have an administrative distance higher than the primary route's AD to serve as a backup.
B.The default administrative distance for a static route is 0.
C.A floating static route will be installed in the routing table immediately after the primary route is removed, even if the next-hop is unreachable.
D.The 'ip route' command can be used to configure a floating static route by specifying an administrative distance value.
E.A floating static route can only be used with OSPF as the primary routing protocol.
AnswersA, D

Correct. The floating static route is configured with a higher AD so it is only used when the primary route (with lower AD) is not available.

Why this answer

A floating static route is a static route with an administrative distance greater than the dynamic routing protocol's AD, so it only appears in the routing table when the dynamic route is lost. The default AD for a static route is 1, but it can be changed. The floating static route will be installed when the primary route (with lower AD) is removed.

The backup route must have a higher AD than the primary route. The distance command under the routing protocol does not affect the static route's AD.

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27
MCQmedium

A network engineer is troubleshooting a BGP route reachability issue. R1 learns the prefix 10.1.1.0/24 via eBGP from R2 with an AD of 20, and via OSPF from R3 with an AD of 110. The engineer notices that R1 installs the OSPF route in the routing table instead of the eBGP route, even though the eBGP route is preferred by default. What is the most likely cause of this behavior?

A.The OSPF route has a lower metric than the eBGP route.
B.The distance bgp 20 200 200 command is configured under the BGP process, increasing the AD of eBGP routes to 200.
C.The OSPF route is an inter-area route, which has a lower AD than intra-area routes.
D.The eBGP route is not the best path because the next-hop is unreachable.
AnswerB

This command sets the AD for eBGP routes to 200, making OSPF (AD 110) preferred.

Why this answer

The default administrative distance for eBGP is 20, and for OSPF is 110, so eBGP should be preferred. However, if the distance command is applied to the eBGP neighbor or the BGP process, it can increase the AD of eBGP routes, making them less preferred than OSPF.

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28
MCQhard

Router R1 and R2 are connected via a serial link running OSPF. R1 has 'ip ospf network point-to-point' configured on the interface, while R2 has default broadcast network type. R1's 'show ip ospf neighbor' shows R2 in FULL state, but R2's 'show ip ospf neighbor' shows R1 in FULL state. However, R1's routing table does not contain a route to a subnet 10.10.10.0/24 that is advertised by R2 via a type-3 LSA. R2's 'show ip route 10.10.10.0' shows it as connected. What is the root cause?

A.The network type mismatch causes R1 to not install the type-3 LSA because the LSA has a DR field that is not valid for point-to-point networks.
B.R2's OSPF process has 'distance 150' set, making the route unreachable.
C.R1 has a distribute-list blocking the 10.10.10.0/24 route.
D.The subnet 10.10.10.0/24 is not in R2's OSPF database due to a missing network command.
AnswerA

OSPF network type mismatch can lead to LSA filtering; point-to-point interfaces ignore LSAs with DR information.

Why this answer

Network type mismatch on a point-to-point link can cause OSPF adjacency to form but may affect LSA propagation. With point-to-point, R1 expects no DR/BDR election and uses a different LSA format. R2, with broadcast, expects DR/BDR.

The adjacency forms because both see each other as neighbors, but the type-3 LSA from R2 might be generated incorrectly or R1 may not accept it due to network type mismatch. The correct answer is that the network type mismatch causes R1 to ignore type-3 LSAs from R2 because R1 expects the link to be point-to-point and R2's LSA includes a DR field that R1 does not process.

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29
MCQmedium

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# debug eigrp packets EIGRP Packets debugging is on (UPDATE, REQUEST, QUERY, REPLY, HELLO, IPXSAP, PROBE, ACK, STUB, SIAQUERY, SIAREPLY) *Mar 1 00:01:23.456: EIGRP: received UPDATE on GigabitEthernet0/0 nbr 10.1.1.2 *Mar 1 00:01:23.456: AS 100, Flags 0x0, Seq 1/0 idbQ 0/0 iidbQ un/rely 0/0 *Mar 1 00:01:23.456: Int: 192.168.5.0/24, metric 30720/28160 *Mar 1 00:01:23.456: EIGRP: Enqueueing UPDATE on GigabitEthernet0/0 nbr 10.1.1.2 iidbQ un/rely 0/1 peerQ un/rely 0/0 serno 1-1 What does this output indicate?

A.The router is receiving an EIGRP update for network 192.168.5.0/24 with a composite metric of 30720/28160.
B.The administrative distance for this route is 90 because it is internal.
C.The router is sending a query for network 192.168.5.0/24.
D.The EIGRP neighbor relationship is down.
AnswerA

The debug shows 'received UPDATE' and the metric.

Why this answer

The debug output shows EIGRP packet exchanges. It does not directly show administrative distance, but it indicates that an update is being sent and received for a specific network.

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30
MCQhard

Router R1 and R2 are running EIGRP. R1 has a route to 172.16.0.0/16 with AD 90. R2 redistributes a static route for 172.16.0.0/16 into EIGRP with a route-map that sets the administrative distance to 85. R1 learns the redistributed route with AD 85 and installs it, overriding the original internal route. However, R1's 'show ip route 172.16.0.0' shows the route via R2 with AD 85, but pings to 172.16.1.1 fail. What is the most likely cause?

A.The redistributed route is a summary route that does not contain the specific subnet 172.16.1.0/24, causing packets to be dropped.
B.The route-map set distance 85 is ignored because EIGRP internal routes always have AD 90.
C.R1's EIGRP process has a distribute-list blocking the redistributed route.
D.The redistributed route has a higher metric than the internal route, but AD overrides metric.
AnswerA

The summary route may point to a null interface or a next hop that does not have the specific route.

Why this answer

Setting AD to 85 makes the redistributed route preferred over the internal route (AD 90). However, the redistributed route might have a less specific prefix (e.g., 172.16.0.0/16) while the internal route might have a more specific prefix (e.g., 172.16.1.0/24) that is now hidden. The ping fails because the redistributed route is a summary that does not have a valid next hop for the specific subnet.

The correct answer is that the redistributed route is a summary that does not include the specific subnet, causing blackholing.

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31
Multi-Selecthard

Which TWO statements about the 'distance' command in Cisco IOS routing protocols are true? (Choose TWO.)

Select 2 answers
A.Under EIGRP, the 'distance eigrp <internal-distance> <external-distance>' command sets different ADs for internal and external routes.
B.Under OSPF, the 'distance ospf <intra-area> <inter-area> <external>' command sets AD for different route types.
C.The 'distance' command can be used to change the AD of connected routes.
D.The 'distance' command requires a route-map to match specific prefixes in all routing protocols.
E.The 'distance' command can be used to set an AD of 0 for a specific route.
AnswersA, B

Correct. EIGRP allows separate AD configuration for internal and external routes using the 'distance eigrp' command.

Why this answer

The distance command can be used to modify the administrative distance for routes learned via a routing protocol. It can be applied globally or with an access-list or prefix-list to match specific routes. The command does not affect the AD of routes from other protocols.

The distance value must be between 1 and 255. The command can be used under EIGRP, OSPF, RIP, and BGP, but the syntax varies slightly.

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32
MCQhard

Router R1 and R2 are running OSPF in area 0. R1 has a loopback interface with IP 192.168.1.1/32 advertised into OSPF. R2 learns this route as an intra-area route (AD 110). R2 also runs RIP and learns the same prefix from R3 with AD 120. R2's 'show ip route 192.168.1.1' shows the RIP route. What is the root cause?

A.R2's OSPF process has 'distance 130' configured, making OSPF routes have AD 130, which is higher than RIP's AD 120.
B.The RIP route has a better metric than the OSPF route.
C.R2 has a static route with AD 1 that overrides both.
D.The OSPF route is an external route with AD 170 due to redistribution.
AnswerA

If OSPF distance is set to 130, RIP (120) becomes preferred.

Why this answer

RIP has AD 120, OSPF has AD 110, so OSPF should be preferred. If the OSPF route is not installed, it could be due to a higher metric or a filter. The correct answer is that the OSPF route is an external route (type-5) because it was redistributed from another protocol, not an intra-area route.

The scenario says intra-area, but if the loopback is not directly connected to OSPF (e.g., it is in a different VRF), it might be redistributed as external. The question states it is advertised into OSPF, but the AD for external is 110, same as intra-area. The trick is that the OSPF route might have a higher metric than the RIP route, but AD is checked first.

The most likely cause is that the OSPF route is not in the routing table due to a distribute-list or because the OSPF process has 'distance 130' configured for all routes.

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33
MCQmedium

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route 192.168.1.0 255.255.255.0 Routing entry for 192.168.1.0/24 Known via "eigrp 100", distance 170, metric 30720, type internal Redistributing via eigrp 100 Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 10.1.1.2, from 10.1.1.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 30720, traffic share count is 1 Total delay is 2000 microseconds, minimum bandwidth is 100000 Kbit Reporting 1 hops What does this output indicate?

A.The route is an EIGRP internal route with a default administrative distance of 90.
B.The route is an EIGRP external route with administrative distance 170, which is the default for external EIGRP routes.
C.The route is redistributed from OSPF into EIGRP, hence the distance of 170.
D.The route is learned via EIGRP but the administrative distance has been manually changed to 170.
AnswerB

EIGRP external routes have a default AD of 170, as shown in the output.

Why this answer

The output shows the route's administrative distance, which is 170 for EIGRP external routes. This is important for understanding route selection when multiple routing protocols are redistributed.

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34
Multi-Selecthard

Which TWO statements about the default administrative distances for different route sources are correct? (Choose TWO.)

Select 2 answers
A.The default administrative distance for a connected interface is 0.
B.The default administrative distance for internal BGP (iBGP) is 20.
C.The default administrative distance for external EIGRP routes is 170.
D.The default administrative distance for RIP is 100.
E.The default administrative distance for OSPF is 90.
AnswersA, C

Correct. Connected routes have the highest trustworthiness with an AD of 0.

Why this answer

Cisco IOS assigns default AD values to various route sources. Connected interfaces have an AD of 0, static routes have 1, EIGRP summary routes have 5, internal BGP has 200, and external EIGRP has 170. OSPF has 110, and RIP has 120.

Knowing these defaults is critical for troubleshooting route selection.

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36
Drag & Dropmedium

Drag and drop the steps to troubleshoot Administrative Distance adjacency or connectivity failures 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, verify the physical connectivity and layer 1/2 status, then check the routing protocol neighbor adjacency, next examine the AD values of the routes learned from the neighbor, then review any route filtering or redistribution policies, and finally test end-to-end connectivity to confirm the fix.

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37
MCQmedium

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip eigrp topology 192.168.3.0/24 all-links IP-EIGRP (AS 100): Topology entry for 192.168.3.0/24 State is Passive, Query origin flag is 1, 1 Successor(s), FD is 30720 Routing Descriptor Blocks: 10.1.1.2 (GigabitEthernet0/0), from 10.1.1.2, Send flag is 0x0 Composite metric is (30720/28160), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 2000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 10.1.2.2 (GigabitEthernet0/1), from 10.1.2.2, Send flag is 0x0 Composite metric is (30720/28160), Route is Internal Vector metric: Minimum bandwidth is 100000 Kbit Total delay is 2000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 1 What does this output indicate?

A.Both paths are feasible successors and will be used for load balancing.
B.Only the first path is used because it has a lower administrative distance.
C.The second path is a feasible successor but not used because the first path has a better metric.
D.The output indicates a routing loop because there are two paths with the same metric.
AnswerA

Both paths have the same metric and meet the feasibility condition (reported distance less than FD), so they are successors and will be used for load balancing.

Why this answer

The output shows two equal-cost paths to the same network, both with the same composite metric and FD. This indicates that EIGRP is load balancing across these two links, but the administrative distance is not directly shown here; it's about the topology table.

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38
MCQhard

An engineer configures IPsec between two routers using a site-to-site VPN. The tunnel does not come up, and the debug output shows 'received unexpected payload type'. Both routers are configured with pre-shared keys. Which is the most likely explanation?

A.The pre-shared keys do not match on both sides.
B.The IKE phase 1 transform sets are mismatched; one router uses AES-256 while the other uses AES-128.
C.The IPsec phase 2 transform sets are mismatched.
D.The access-list defining interesting traffic is missing on one router.
AnswerB

Mismatched encryption or hash algorithms cause the IKE negotiation to fail with 'unexpected payload type' because the proposals do not align.

Why this answer

The 'received unexpected payload type' error typically indicates a mismatch in the IKE phase 1 parameters, such as encryption, hash, or DH group. Even if the pre-shared key matches, a mismatch in transform sets or IKE proposals causes the error.

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39
MCQeasy

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip ospf interface detail GigabitEthernet0/0 GigabitEthernet0/0 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0, Attached via Network Statement Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1 Topology-MTID Cost Disabled Shutdown Topology Name 0 1 no no Base Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 1.1.1.1, Interface address 10.1.1.1 Backup Designated router (ID) 2.2.2.2, Interface address 10.1.1.2 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 oob-resync timeout 40 Hello due in 00:00:03 Supports Link-local Signaling (LLS) Cisco NSF helper support enabled IETF NSF helper support enabled Can be protected by per-prefix Loop-Free Fast Reroute Can be used for per-prefix Loop-Free Fast Reroute remote-LFA tunnels Index 1/1/1, flood queue length 0 Next 0x0(0)/0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 2.2.2.2 (Backup Designated Router) Suppress hello for 0 neighbor(s) What does this output indicate?

A.The interface is an OSPF broadcast interface with a cost of 1, and the router is the Designated Router.
B.The interface has an administrative distance of 110.
C.The neighbor 2.2.2.2 is not fully adjacent because it is a backup designated router.
D.The OSPF process ID is 100.
AnswerA

The output clearly states State DR, indicating this router is the Designated Router on this segment.

Why this answer

The output shows detailed OSPF interface information, including the cost, timers, and neighbor state. It does not directly show administrative distance, but it is relevant for understanding OSPF operation.

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40
MCQhard

A network engineer is troubleshooting a multi-homed BGP setup. R1 receives the prefix 10.1.1.0/24 from two eBGP peers: R2 (AS 100) and R3 (AS 200). The engineer configures the distance bgp 20 20 20 command on R1 to make all BGP routes have the same AD. However, R1 still prefers the route from R2 over R3. What is the most likely reason?

A.The route from R2 has a lower MED than the route from R3.
B.The route from R2 has a higher local preference than the route from R3.
C.The route from R2 is the oldest BGP route.
D.The AS path for the route from R2 is shorter than that from R3.
AnswerB

Local preference is compared before AS path and MED; if R2's route has a higher local preference (e.g., 150 vs 100), it will be preferred even with equal AD.

Why this answer

The distance bgp command sets AD for eBGP, iBGP, and local routes. With AD equal, the router uses other BGP path attributes, such as local preference, AS path length, or MED. The most common tie-breaker is local preference (default 100) or the oldest route.

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41
MCQhard

In a multi-area OSPF network, Router R1 (ABR) is redistributing a static default route into OSPF with 'default-information originate always metric 10'. Router R2, an internal router in Area 1, receives the default route but also learns a more specific route to 0.0.0.0/0 via EIGRP from Router R3 with administrative distance 170. The 'show ip route 0.0.0.0' on R2 shows the EIGRP route as the best path. However, R2's 'show ip ospf database external' shows the OSPF external default route. What is the root cause of R2 preferring the EIGRP route?

A.The EIGRP route has an administrative distance of 90 because it is an internal EIGRP route, and the OSPF default route is external with AD 110, so EIGRP is preferred.
B.The OSPF default route is not installed because the 'default-information originate always' command requires a 'metric-type' keyword to be set to type-1 for lower AD.
C.R2 has a static route with AD 1 that is overriding both dynamic routes.
D.The EIGRP route is learned from a different VRF, and VRF routes have lower AD by default.
AnswerA

Internal EIGRP routes have AD 90, which is lower than OSPF external routes (AD 110). The redistribution on R3 is injecting the route as internal, causing the preference.

Why this answer

OSPF external routes have an administrative distance of 110, while EIGRP external routes have an administrative distance of 170. Since 110 < 170, OSPF should be preferred. However, if the EIGRP route is internal (AD 90) due to redistribution settings or if the OSPF route is not installed due to a mismatched metric type or route filtering, the EIGRP route might be chosen.

The correct answer is that the OSPF default route is an NSSA external route (Type N2) with AD 110, but the EIGRP route is internal (AD 90) because it was redistributed as internal via a route-map that changed the administrative distance. The candidate must check the redistribution configuration on R3.

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42
MCQhard

An engineer enables uRPF (strict mode) on an interface facing the Internet. Legitimate traffic from a customer network is being dropped. The customer network uses asymmetric routing where return traffic takes a different path. Which is the most likely explanation?

A.The uRPF strict mode requires that the source IP's best path is out the same interface; asymmetric routing violates this.
B.The uRPF loose mode should be used instead, as it only requires a route to the source IP in the FIB.
C.The customer network is using private IP addresses that are not routable.
D.The uRPF allow-default option is missing, which is required for default routes.
AnswerA

Strict mode drops packets if the reverse path does not match the incoming interface, which occurs with asymmetric routing.

Why this answer

Strict uRPF checks that the source IP of incoming packets has a route in the FIB pointing back to the same interface. With asymmetric routing, the return path may use a different interface, causing the check to fail and the packet to be dropped.

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43
MCQmedium

An engineer is troubleshooting a route redistribution issue between OSPF and EIGRP. R1 runs both protocols and redistributes OSPF into EIGRP. The engineer notices that OSPF routes redistributed into EIGRP have an AD of 170, but some routes from OSPF are not being redistributed. What is the most likely cause?

A.The OSPF routes have a higher metric than the EIGRP routes.
B.The OSPF routes are not in the routing table because they are overridden by a static route with AD 1.
C.The redistribute ospf 1 metric 10000 command is missing.
D.The OSPF routes are external type 2, which are not redistributed by default.
AnswerB

If a static route with AD 1 exists for the same prefix, the OSPF route will not be installed, and redistribution will not include it.

Why this answer

Redistribution into EIGRP requires matching routes; by default, only routes in the routing table are redistributed. If OSPF routes are not in the routing table because they are overridden by another protocol with lower AD, they will not be redistributed.

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44
MCQeasy

A network engineer runs the following command on Router R6: R6# show ip route 10.0.0.0 Routing entry for 10.0.0.0/8 Known via "eigrp 100", distance 90, metric 28160 Redistributing via eigrp 100 Last update from 192.168.1.1 on GigabitEthernet0/0, 00:00:10 ago Routing Descriptor Blocks: * 192.168.1.1, from 192.168.1.1, 00:00:10 ago, via GigabitEthernet0/0 Route metric is 28160, traffic share count is 1 Additionally, an OSPF route for the same prefix is learned with distance 110. Which route will be installed in the routing table?

A.The OSPF route will be installed because it has a lower metric.
B.The EIGRP route will be installed because it has a lower administrative distance.
C.Both routes will be installed for load balancing.
D.Neither route will be installed due to a conflict.
AnswerB

EIGRP's distance of 90 is lower than OSPF's 110, so the EIGRP route is preferred.

Why this answer

EIGRP internal routes have a default administrative distance of 90, which is lower than OSPF's default distance of 110. Therefore, the EIGRP route will be preferred and installed in the routing table.

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45
MCQeasy

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route 10.0.0.0 255.0.0.0 Routing entry for 10.0.0.0/8 Known via "static", distance 1, metric 0 Redistributing via eigrp 100 Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 10.1.1.2, from 10.1.1.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 0, traffic share count is 1 What does this output indicate?

A.The route is a static route with administrative distance 1, which is the default for static routes pointing to an interface.
B.The route is an EIGRP route with administrative distance 90.
C.The route is being redistributed from EIGRP into static.
D.The route has an administrative distance of 170 because it is external.
AnswerA

Static routes have a default AD of 1.

Why this answer

The output shows a static route with administrative distance 1, which is the default for static routes. This route is being redistributed into EIGRP.

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46
MCQeasy

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# show ip route 172.16.0.0 255.255.0.0 Routing entry for 172.16.0.0/16 Known via "ospf 1", distance 110, metric 20, type intra area Last update from 10.1.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 10.1.1.2, from 2.2.2.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 20, traffic share count is 1 What does this output indicate?

A.The route is an OSPF intra-area route with administrative distance 110, which is the default for OSPF.
B.The route is an OSPF external route with administrative distance 110.
C.The route has an administrative distance of 20 because it is an OSPF route.
D.The route is preferred over an EIGRP route with AD 90.
AnswerA

OSPF routes have a default AD of 110.

Why this answer

The output shows an OSPF intra-area route with administrative distance 110, which is the default for OSPF. The metric is 20, and the route is learned from neighbor 2.2.2.2.

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48
Multi-Selectmedium

Which TWO commands can be used to verify the administrative distance of a route in a Cisco IOS router? (Choose TWO.)

Select 2 answers
A.show ip route
B.show ip protocols
C.show ip interface brief
D.show running-config | include distance
E.show ip ospf interface
AnswersA, B

This command shows the routing table, where each entry includes the administrative distance (e.g., [110/20]).

Why this answer

The show ip route command displays the routing table including the administrative distance for each route. The show ip protocols command displays routing protocol parameters including the default and any configured administrative distances. The other options either do not show administrative distance or are incorrect commands.

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49
Multi-Selecthard

Which TWO configuration steps are required to change the administrative distance for routes learned from a specific neighbor in EIGRP? (Choose TWO.)

Select 2 answers
A.Configure a prefix list to match the routes from the neighbor.
B.Use the distance eigrp command in router configuration mode.
C.Use the distance command with the neighbor IP address and prefix list.
D.Configure an access list to permit the routes from the neighbor.
E.Use the redistribute command to change the administrative distance.
AnswersA, C

The prefix list is used to identify which routes to match for the distance override.

Why this answer

To change the AD for routes from a specific EIGRP neighbor, you must first configure a prefix list to match the routes, then apply it using the distance command in EIGRP router configuration mode. The distance command can specify a different AD for routes matching a prefix list from a specific neighbor.

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50
MCQmedium

A network engineer runs the following command on Router R3: R3# show ip route 172.16.1.0 Routing entry for 172.16.1.0/24 Known via "bgp 65000", distance 20, metric 0 Redistributing via bgp 65000 Last update from 192.168.1.1 00:00:15 ago Routing Descriptor Blocks: * 192.168.1.1, from 192.168.1.1, 00:00:15 ago Route metric is 0, traffic share count is 1 Based on this output, what can be concluded about the administrative distance?

A.The route is an iBGP route with a manually configured distance of 20.
B.The route is an eBGP route, as the distance 20 is the default for eBGP.
C.The route is redistributed from OSPF into BGP.
D.The administrative distance of 20 is non-standard and must have been changed.
AnswerB

eBGP routes have a default administrative distance of 20, matching this output.

Why this answer

The default administrative distance for BGP is 20 for eBGP routes and 200 for iBGP routes. A distance of 20 indicates this is an eBGP route. The metric of 0 is typical for eBGP routes.

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51
MCQmedium

Examine this configuration snippet: ``` router rip distance 120 ``` Which statement is true about the effect of this command?

A.It changes the administrative distance for RIP routes to 120, which is the same as the default, so no change occurs.
B.It changes the administrative distance for RIP routes to 120, which is lower than the default of 130.
C.It changes the administrative distance for RIP routes to 120, but only for routes learned from RIP neighbors.
D.It changes the administrative distance for RIP routes to 120, but only for routes with a hop count greater than 1.
AnswerA

RIP default AD is 120, so setting it to 120 has no effect.

Why this answer

The `distance` command under RIP sets the administrative distance for all RIP routes to 120, overriding the default of 120? Actually default is 120, so this command would have no effect if set to the same value.

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52
MCQmedium

Consider the following configuration on a router running BGP and OSPF: ``` router bgp 65000 distance bgp 20 200 200 ``` What is the effect of this command?

A.It sets the administrative distance for eBGP routes to 20, iBGP routes to 200, and local BGP routes to 200.
B.It sets the administrative distance for all BGP routes to 20.
C.It sets the administrative distance for eBGP routes to 200 and iBGP routes to 20.
D.It sets the administrative distance for BGP routes to 20 for routes learned from AS 65000.
AnswerA

Syntax: `distance bgp <external> <internal> <local>`.

Why this answer

The `distance bgp` command sets AD for BGP routes: external (eBGP) to 20, internal (iBGP) to 200, and local to 200.

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53
MCQhard

Router R1 and R2 are running EIGRP as the IGP, and R1 is redistributing a connected subnet 10.1.1.0/24 into EIGRP. R2 also runs BGP with an external peer, and BGP is redistributing the same prefix 10.1.1.0/24 into EIGRP with a route-map that sets the administrative distance to 100. On R3, a downstream EIGRP router, 'show ip route 10.1.1.0' shows the route via R2. What is the most likely cause of suboptimal routing?

A.The route-map set distance 100 overrides the default AD, making the redistributed route preferred over the internal route (AD 90).
B.The internal EIGRP route is not present in R3's routing table due to a distribute-list inbound from R1, so the redistributed route with AD 100 is the only path.
C.The redistributed route has AD 170 by default, and the route-map is ignored because redistribution from BGP always uses AD 170.
D.R3 prefers routes with lower metric, not AD, and the redistributed route has a better metric.
AnswerB

If the internal route is filtered, the redistributed route becomes the best path, causing suboptimal routing.

Why this answer

EIGRP internal routes have AD 90, external routes AD 170. Redistribution from BGP into EIGRP creates external routes (AD 170) unless a route-map changes the distance. Setting AD to 100 makes the redistributed route preferred over the original internal route (AD 90) because 100 > 90, so the internal route should be preferred.

However, if the internal route is not present due to a filter, or if the distance is set lower than 90, the redistributed route is chosen. The correct answer is that the route-map set distance 100 is higher than 90, so the internal route (AD 90) is still preferred; the issue is that the internal route is being suppressed by a distribute-list on R3.

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55
Multi-Selecthard

Which TWO statements about the behavior of administrative distance in Cisco IOS are correct? (Choose TWO.)

Select 2 answers
A.The default administrative distance for an EIGRP summary route is 5.
B.The default administrative distance for OSPF is 90.
C.The distance command applied under a routing protocol can modify the AD for all routes, including connected and static routes, learned via that protocol.
D.The show ip route command displays the administrative distance of each route in the routing table.
E.When two different routing protocols provide routes to the same destination, the route with the higher administrative distance is installed in the routing table.
AnswersA, D

Correct. EIGRP summary routes have a default AD of 5, which is lower than the AD of any dynamic routing protocol, ensuring they are preferred.

Why this answer

Administrative distance (AD) is a trustworthiness metric used to select the best route among multiple routing protocols. A lower AD is preferred. The default AD for EIGRP summary routes is 5, which is lower than the default AD for OSPF (110).

The distance command can be applied to a routing process to change the AD for all routes learned via that protocol, but it does not affect connected or static routes unless explicitly configured. The show ip route command displays the AD of each route, and the AD value is used to break ties when multiple protocols provide routes to the same destination.

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56
MCQmedium

A network engineer runs the following command on Router R2: R2# show ip route 192.168.10.0 Routing entry for 192.168.10.0/24 Known via "ospf 1", distance 110, metric 20 Redistributing via ospf 1 Last update from 10.0.0.1 on GigabitEthernet0/1, 00:00:10 ago Routing Descriptor Blocks: * 10.0.0.1, from 10.0.0.1, 00:00:10 ago, via GigabitEthernet0/1 Route metric is 20, traffic share count is 1 Based on this output, what is the most likely origin of this route?

A.The route is an OSPF intra-area route.
B.The route is an OSPF inter-area route.
C.The route is an OSPF external route, likely redistributed.
D.The route is an OSPF NSSA external route.
AnswerC

The metric of 20 is the default for OSPF external type 2 routes, indicating redistribution.

Why this answer

The metric of 20 is the default metric for OSPF external routes of type E2 (external type 2). The administrative distance of 110 is the default for OSPF routes. This combination indicates the route was redistributed into OSPF from another protocol.

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57
MCQmedium

Consider the following partial configuration on a Cisco IOS-XE router: ``` router eigrp 100 network 10.0.0.0 distance eigrp 90 170 ``` What is the effect of the `distance eigrp 90 170` command?

A.It sets the administrative distance for all EIGRP routes to 90.
B.It sets the administrative distance for EIGRP internal routes to 90 and external routes to 170.
C.It sets the administrative distance for EIGRP routes to 170 for all routes learned from neighbors with an AS of 100.
D.It sets the metric weights for EIGRP to 90 and 170.
AnswerB

The syntax is `distance eigrp <internal-distance> <external-distance>`.

Why this answer

This command sets the administrative distance for EIGRP internal routes to 90 and external routes to 170.

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58
MCQhard

A network engineer runs the following command to troubleshoot an Administrative Distance issue: R1# debug ip routing IP routing debugging is on *Mar 1 00:01:23.456: RT: add 192.168.2.0/24 via 10.1.1.2, eigrp metric [170/30720] *Mar 1 00:01:23.456: RT: closer admin distance for 192.168.2.0, adding to routing table *Mar 1 00:01:23.456: RT: add 192.168.2.0/24 via 10.1.1.2, ospf metric [110/20] *Mar 1 00:01:23.456: RT: not add 192.168.2.0/24 via 10.1.1.2, ospf metric [110/20] - route already in table with better admin distance What does this output indicate?

A.The EIGRP route is preferred because it was added first.
B.The OSPF route is preferred because it has a lower administrative distance of 110 compared to EIGRP's 170.
C.The EIGRP route remains in the routing table because its administrative distance was manually changed to 100, making it better than OSPF's 110.
D.Both routes are added to the routing table, and load balancing occurs.
AnswerC

The debug shows the OSPF route is not added because the existing EIGRP route has a better admin distance. Since default EIGRP external AD is 170, it must have been changed to a value lower than 110, such as 100.

Why this answer

The debug shows that the EIGRP route (AD 170) is added first, but then OSPF (AD 110) tries to add the same route. Since OSPF has a lower AD, it replaces the EIGRP route. The output indicates that the route from OSPF is preferred due to lower administrative distance.

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60
Drag & Dropmedium

Drag and drop the steps to verify and validate the Administrative Distance operational state 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

Start by showing the IP routing table to see which routes are installed, then display the specific route with its AD, next check the routing protocol database for the prefix, then verify the protocol-specific AD configuration, and finally compare the AD with other protocols to ensure correct preference.

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61
MCQhard

A network engineer is troubleshooting a situation where R1 has two routes to 10.0.0.0/8: one via OSPF (AD 110) and one via RIP (AD 120). The engineer wants R1 to prefer the RIP route. After configuring the distance 80 0.0.0.0 255.255.255.255 under the RIP process, the RIP route is still not preferred. What is the most likely reason?

A.The OSPF route has an AD of 110, but the RIP route's AD was set to 80, so RIP should be preferred. The issue is that the distance command was applied to the wrong prefix.
B.The OSPF process has the distance ospf external 70 command configured, lowering the AD of OSPF external routes to 70.
C.The RIP route is not in the routing table because it is suppressed by a distribute-list.
D.The distance command under RIP only affects internal RIP routes, not redistributed routes.
AnswerB

If OSPF AD is lowered to 70, it will still be preferred over RIP with AD 80.

Why this answer

The distance command under RIP can set AD for specific routes. However, if the OSPF route has a lower AD than the new RIP AD, it will still be preferred. The engineer set RIP AD to 80, but OSPF AD is 110, so RIP should be preferred.

If it is not, the OSPF AD may have been lowered or the distance command was applied incorrectly.

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62
Multi-Selectmedium

Which TWO statements about administrative distance are true? (Choose TWO.)

Select 2 answers
A.A lower administrative distance is preferred over a higher one.
B.Administrative distance is used to compare routes from different routing protocols.
C.The default administrative distance for OSPF is 90.
D.Administrative distance is used to compare routes within the same routing protocol.
E.The default administrative distance for EIGRP internal routes is 170.
AnswersA, B

The route with the lowest administrative distance is installed in the routing table.

Why this answer

Administrative distance is used to select the best route when multiple routing protocols provide routes to the same destination. A lower administrative distance is preferred. The default administrative distance for OSPF is 110, and for EIGRP it is 90 (internal) or 170 (external).

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63
MCQmedium

A network engineer runs the following command on Router R1: R1# show ip route 10.1.1.0 Routing entry for 10.1.1.0/24 Known via "eigrp 100", distance 170, metric 30720 Redistributing via eigrp 100 Last update from 192.168.1.2 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 192.168.1.2, from 192.168.1.2, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 30720, traffic share count is 1 Based on this output, which statement is correct?

A.The route 10.1.1.0/24 is an EIGRP internal route.
B.The route 10.1.1.0/24 is an EIGRP external route, likely redistributed.
C.The route 10.1.1.0/24 is learned via OSPF and redistributed into EIGRP.
D.The administrative distance of 170 is non-default and must have been manually configured.
AnswerB

The administrative distance of 170 is the default for EIGRP external routes, confirming redistribution.

Why this answer

The output shows an EIGRP route with an administrative distance of 170, which is the default distance for EIGRP external routes. This indicates the route was redistributed into EIGRP from another protocol or process. The metric of 30720 is the default for a redistributed connected route.

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64
MCQhard

A network engineer runs the following command on Router R8: R8# show ip route 10.2.2.0 Routing entry for 10.2.2.0/24 Known via "eigrp 100", distance 90, metric 28160 Redistributing via eigrp 100 Last update from 192.168.2.1 on GigabitEthernet0/0, 00:00:05 ago Routing Descriptor Blocks: * 192.168.2.1, from 192.168.2.1, 00:00:05 ago, via GigabitEthernet0/0 Route metric is 28160, traffic share count is 1 R8 also has a static route to 10.2.2.0/24 with next-hop 192.168.3.1 configured with distance 95. Which route will be used?

A.The static route will be used because it is manually configured.
B.The EIGRP route will be used because it has a lower administrative distance.
C.Both routes will be used for load balancing.
D.Neither route will be used due to a routing loop.
AnswerB

EIGRP's distance of 90 is lower than the static route's 95, so EIGRP is preferred.

Why this answer

The EIGRP route has a distance of 90, which is lower than the static route's distance of 95. Therefore, the EIGRP route will be preferred and installed in the routing table.

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65
MCQmedium

Examine this configuration: ``` router ospf 1 distance ospf intra-area 150 inter-area 160 external 170 ``` What is the effect of this command?

A.It sets the administrative distance for all OSPF routes to 150.
B.It sets the administrative distance for intra-area OSPF routes to 150, inter-area to 160, and external to 170.
C.It sets the administrative distance for OSPF routes to 150, but only for routes learned from area 1.
D.It sets the administrative distance for OSPF external routes to 170 and leaves intra-area and inter-area at default.
AnswerB

This is the correct syntax and effect.

Why this answer

This command sets different administrative distances for different OSPF route types: intra-area to 150, inter-area to 160, external to 170.

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66
Multi-Selectmedium

Which THREE statements about administrative distance are true when comparing OSPF and EIGRP? (Choose THREE.)

Select 3 answers
A.By default, EIGRP internal routes are preferred over OSPF routes.
B.By default, OSPF routes are preferred over EIGRP external routes.
C.The administrative distance for OSPF can be changed using the distance ospf command.
D.EIGRP internal routes have a default administrative distance of 170.
E.OSPF external routes have a default administrative distance of 110.
AnswersA, B, C

EIGRP internal AD is 90, OSPF is 110, so EIGRP is preferred.

Why this answer

OSPF has a default AD of 110, EIGRP internal routes have 90, and EIGRP external routes have 170. Therefore, EIGRP internal routes are preferred over OSPF, but OSPF is preferred over EIGRP external routes. Administrative distance can be manually changed for either protocol.

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68
MCQmedium

A network engineer runs the following command on Router R5: R5# show ip route 192.168.100.0 Routing entry for 192.168.100.0/24 Known via "static", distance 1, metric 0 Redistributing via ospf 1 Last update from 10.0.0.2 on GigabitEthernet0/1, 00:00:05 ago Routing Descriptor Blocks: * 10.0.0.2, via GigabitEthernet0/1 Route metric is 0, traffic share count is 1 Based on this output, what is the likely issue if this route is not being preferred over an EIGRP route with distance 90?

A.The static route is not preferred because its distance is higher than EIGRP's default distance of 90.
B.The static route may have been configured with a higher distance as a floating static route.
C.EIGRP always has a lower administrative distance than static routes.
D.The static route is redistributed into OSPF, which changes its distance.
AnswerB

If the static route is not preferred, it might have a manually configured distance greater than 90, making it a floating static route.

Why this answer

The static route has a default distance of 1, which is lower than EIGRP's default distance of 90. If the static route is not preferred, it may have a higher distance if configured as a floating static route, or the EIGRP route may have a lower distance due to configuration.

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69
MCQmedium

What is the default administrative distance for a static route pointing to an interface (e.g., 'ip route 10.0.0.0 255.0.0.0 GigabitEthernet0/1')?

A.0
B.1
C.5
D.110
AnswerA

When a static route uses only an exit interface, it is considered directly connected and gets AD 0.

Why this answer

A static route configured with an exit interface (not a next-hop IP) has a default AD of 0, because it is treated as a directly connected route. However, if a next-hop IP is specified, the default AD is 1.

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70
MCQhard

An engineer configures mutual redistribution between OSPF and EIGRP on a router. After a few minutes, the router's CPU spikes and routing loops occur. Which is the most likely explanation?

A.The seed metric for EIGRP was not configured, causing the route to be redistributed with an infinite metric.
B.The administrative distance of the redistributed routes is lower than the original, causing them to be preferred.
C.Routes redistributed from OSPF into EIGRP are then redistributed back into OSPF, creating a feedback loop.
D.The OSPF process ID must match on all routers; otherwise, redistribution fails.
AnswerC

Without filtering or tagging, redistributed routes can be re-injected into the original protocol, causing instability.

Why this answer

Mutual redistribution without route tagging or filtering can cause a routing loop. A route redistributed from OSPF into EIGRP can be redistributed back into OSPF, creating a feedback loop. This is a classic redistribution loop.

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71
MCQhard

An engineer applies a Control Plane Policing (CoPP) policy to a router. After applying, the router becomes unreachable via SSH and SNMP, even though the policy allows management traffic. Which is the most likely explanation?

A.The CoPP policy was applied to the wrong interface; it must be applied to the management interface.
B.The class-map for management traffic does not include all required protocols, and the class-default action is drop.
C.The CoPP policy uses rate-limit in bps instead of pps, causing all traffic to be policed.
D.The CoPP policy was applied before the class-maps were fully configured.
AnswerB

If class-default is not configured with a permit action, the implicit deny drops unmatched traffic, including management traffic not explicitly matched.

Why this answer

CoPP policies have an implicit deny at the end of the class-map. If the class-map for management traffic does not explicitly match all management protocols (e.g., SSH, SNMP, NTP), or if the policy does not have a class-default action to permit, the traffic is dropped.

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72
MCQeasy

A network engineer runs the following command on Router R4: R4# show ip route 10.10.10.0 Routing entry for 10.10.10.0/24 Known via "connected", distance 0, metric 0 (connected) Redistributing via eigrp 100 Last update from 10.10.10.1 on GigabitEthernet0/0, 00:00:00 ago Routing Descriptor Blocks: * 10.10.10.1, via GigabitEthernet0/0 Route metric is 0, traffic share count is 1 Based on this output, which statement is true?

A.The route is a static route with distance 0.
B.The route is a connected route, as indicated by distance 0.
C.The route is redistributed from EIGRP into connected.
D.The administrative distance of 0 indicates a floating static route.
AnswerB

Connected routes have an administrative distance of 0, confirming this is a directly connected network.

Why this answer

The route is directly connected, as indicated by 'known via connected' and distance 0. The administrative distance of 0 is the default for connected routes.

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73
MCQmedium

A network engineer runs the following command on Router R7: R7# show ip route 172.16.0.0 Routing entry for 172.16.0.0/16 Known via "bgp 65000", distance 200, metric 0 Redistributing via bgp 65000 Last update from 10.0.0.1 00:00:20 ago Routing Descriptor Blocks: * 10.0.0.1, from 10.0.0.1, 00:00:20 ago Route metric is 0, traffic share count is 1 Based on this output, what type of BGP route is this?

A.This is an eBGP route because the distance is 200.
B.This is an iBGP route because the distance is 200.
C.This is a redistributed route from OSPF into BGP.
D.The distance of 200 is non-default and manually configured.
AnswerB

iBGP routes have a default administrative distance of 200, matching this output.

Why this answer

The administrative distance of 200 is the default for iBGP routes. eBGP routes have a default distance of 20. Therefore, this is an iBGP route.

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74
MCQhard

An engineer configures route redistribution from EIGRP into OSPF. The redistributed routes appear in the OSPF database but are not installed in the routing table of other OSPF routers. Which is the most likely explanation?

A.The OSPF process on the redistributing router does not have a router-id configured.
B.The redistributed routes have a metric of 0, which OSPF treats as unreachable.
C.The administrative distance of OSPF external routes (110) is higher than EIGRP (90), so the EIGRP routes are preferred.
D.The redistribute command is missing the subnets keyword, causing only classful routes to be redistributed.
AnswerB

OSPF requires a non-zero metric for external routes; a metric of 0 (default for type 1) can cause the route to be ignored.

Why this answer

When redistributing into OSPF, a seed metric must be specified. If not, OSPF defaults to a metric of 20 for external type 2 routes, but if the metric-type is set to 1, the default metric is 0, which may cause the route to be considered unreachable or not installed.

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75
MCQmedium

Given the following configuration on a router: ``` router ospf 1 distance 150 ``` What is the effect of this configuration?

A.It sets the administrative distance for OSPF routes to 150, but only for intra-area routes.
B.It sets the administrative distance for OSPF routes to 150, overriding the default of 110.
C.It sets the administrative distance for OSPF external routes to 150.
D.It sets the administrative distance for OSPF routes to 150, but only for routes learned from a specific neighbor.
AnswerB

The default AD for OSPF is 110; this command changes it to 150.

Why this answer

This command sets the administrative distance for all OSPF routes to 150, overriding the default of 110.

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