Route Maps and Route Filtering practice questions

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A network engineer is troubleshooting a BGP route filtering issue. Router R1 is advertising a prefix 10.1.1.0/24 to its eBGP neighbor R2, but R2 is not receiving it. The engineer checks R1's BGP configuration and sees a route-map named FILTER-OUT applied outbound to the neighbor. The route-map references an ACL that permits 10.1.1.0/24, but the prefix is still not being sent. What is the most likely cause?

Trap 1: The ACL is using the wrong wildcard mask; it should be 0.0.0.255…

Incorrect because the wildcard mask 0.0.0.0 matches only the exact prefix, which is fine for 10.1.1.0/24.

Trap 2: The neighbor is configured with 'soft-reconfiguration inbound'…

Incorrect because soft-reconfiguration inbound only affects inbound updates, not outbound.

Trap 3: The route-map is applied inbound instead of outbound on R1.

Incorrect because the scenario states the route-map is applied outbound.

A
The route-map is missing a 'permit' statement; the default action is deny.
Correct because route-maps without an explicit permit will implicitly deny all prefixes.
B
The ACL is using the wrong wildcard mask; it should be 0.0.0.255 instead of 0.0.0.0.
Why wrong: Incorrect because the wildcard mask 0.0.0.0 matches only the exact prefix, which is fine for 10.1.1.0/24.
C
The neighbor is configured with 'soft-reconfiguration inbound' which blocks outbound updates.
Why wrong: Incorrect because soft-reconfiguration inbound only affects inbound updates, not outbound.
D
The route-map is applied inbound instead of outbound on R1.
Why wrong: Incorrect because the scenario states the route-map is applied outbound.

Question 2hardmultiple choice

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A network engineer is troubleshooting a redistribution issue between OSPF and EIGRP. Router R3 is redistributing OSPF routes into EIGRP, but some OSPF external routes are not appearing in the EIGRP topology table. The engineer checks the redistribute command under EIGRP and sees a route-map named RM-OSPF that uses a prefix-list to match specific prefixes. The missing routes are permitted by the prefix-list. What is the most likely cause?

Trap 1: The prefix-list is using the wrong sequence number and is being…

Incorrect because the scenario says the missing routes are permitted by the prefix-list.

Trap 2: The OSPF routes are type-5 LSAs, which cannot be redistributed into…

Incorrect because OSPF external routes (type-5) can be redistributed into EIGRP.

Trap 3: The route-map is applied to the OSPF process instead of the EIGRP…

Incorrect because the redistribute command is under EIGRP.

A
The route-map is missing a 'set metric' command; EIGRP requires a metric for redistributed routes.
Correct because EIGRP will not accept redistributed routes without an explicit metric.
B
The prefix-list is using the wrong sequence number and is being overridden by a later deny statement.
Why wrong: Incorrect because the scenario says the missing routes are permitted by the prefix-list.
C
The OSPF routes are type-5 LSAs, which cannot be redistributed into EIGRP.
Why wrong: Incorrect because OSPF external routes (type-5) can be redistributed into EIGRP.
D
The route-map is applied to the OSPF process instead of the EIGRP process.
Why wrong: Incorrect because the redistribute command is under EIGRP.

Study the full ACL explanation →

Question 3mediummultiple choice

A network engineer is troubleshooting a PBR (Policy-Based Routing) issue on router R5. The engineer configured a route-map to set the next-hop for traffic from a specific source subnet. The route-map is applied to the incoming interface, but traffic from the source subnet is still being forwarded using the regular routing table. The engineer verifies that the ACL matches the traffic correctly. What is the most likely cause?

Trap 1: The route-map is applied outbound instead of inbound on the…

Incorrect because PBR is applied inbound on the interface where traffic arrives.

Trap 2: The ACL is using a standard ACL, which cannot match source subnet…

Incorrect because standard ACLs can match source subnet with proper wildcard mask.

Trap 3: The route-map has a 'set default interface' command that overrides…

Incorrect because 'set default interface' is used for default routes, not for PBR next-hop.

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A
The route-map is missing a 'set ip next-hop' command, or the next-hop is not reachable.
Correct because without a valid 'set' command, PBR does not alter forwarding.
B
The route-map is applied outbound instead of inbound on the interface.
Why wrong: Incorrect because PBR is applied inbound on the interface where traffic arrives.
C
The ACL is using a standard ACL, which cannot match source subnet correctly.
Why wrong: Incorrect because standard ACLs can match source subnet with proper wildcard mask.
D
The route-map has a 'set default interface' command that overrides the next-hop.
Why wrong: Incorrect because 'set default interface' is used for default routes, not for PBR next-hop.

Question 4hardmultiple choice

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A network engineer is troubleshooting a route filtering problem with prefix-lists. Router R6 is using a prefix-list to filter routes from a BGP neighbor. The prefix-list is configured to permit only 192.168.0.0/16 and 192.168.1.0/24, but routes with prefix 192.168.2.0/24 are also being accepted. The engineer checks the prefix-list configuration and sees only two permit statements. What is the most likely cause?

Trap 1: The prefix-list has an implicit permit at the end for all routes.

Incorrect because prefix-lists have an implicit deny at the end.

Trap 2: The prefix-list is using 'ge 24' which permits any prefix with a…

Incorrect because the scenario says only two permit statements without ge/le.

Trap 3: The BGP neighbor is configured with 'soft-reconfiguration inbound'…

Incorrect because soft-reconfiguration stores updates but does not override filtering.

A
The prefix-list is not applied to the BGP neighbor; the neighbor is using a different filter or no filter.
Correct because if the prefix-list is not applied, no filtering occurs.
B
The prefix-list has an implicit permit at the end for all routes.
Why wrong: Incorrect because prefix-lists have an implicit deny at the end.
C
The prefix-list is using 'ge 24' which permits any prefix with a mask >= 24, including 192.168.2.0/24.
Why wrong: Incorrect because the scenario says only two permit statements without ge/le.
D
The BGP neighbor is configured with 'soft-reconfiguration inbound' which overrides prefix-list filtering.
Why wrong: Incorrect because soft-reconfiguration stores updates but does not override filtering.

Question 5hardmultiple choice

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A network engineer is troubleshooting a redistribution loop between OSPF and EIGRP. Router R7 is redistributing EIGRP routes into OSPF, and also redistributing OSPF routes into EIGRP. The engineer notices that some OSPF routes are appearing in the EIGRP topology table with a higher metric than expected, causing suboptimal routing. What is the most likely cause?

Trap 1: The OSPF process has a 'default-information originate' command that…

Incorrect because this would inject a default route, not affect metrics.

Trap 2: The EIGRP process has a 'variance' command that is causing…

Incorrect because variance affects load balancing, not redistribution metrics.

Trap 3: The route-map applied to redistribution is missing a 'match tag'…

Incorrect because the issue is re-redistribution, not filtering of specific tags.

A
Routes are being re-redistributed due to missing route tags; a route-map with 'set tag' should be used to prevent loops.
Correct because route tags allow filtering to prevent redistribution loops.
B
The OSPF process has a 'default-information originate' command that is injecting a default route into EIGRP.
Why wrong: Incorrect because this would inject a default route, not affect metrics.
C
The EIGRP process has a 'variance' command that is causing unequal-cost load balancing.
Why wrong: Incorrect because variance affects load balancing, not redistribution metrics.
D
The route-map applied to redistribution is missing a 'match tag' statement to filter out redistributed routes.
Why wrong: Incorrect because the issue is re-redistribution, not filtering of specific tags.

Question 6mediummultiple choice

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A network engineer is troubleshooting a BGP route-map that is supposed to set a community value on routes from a specific neighbor. The engineer configures a route-map with 'set community 100:100' and applies it inbound to the neighbor. After the configuration, the engineer checks the BGP table on the local router and sees that the routes do not have the community set. What is the most likely cause?

Trap 1: The route-map is applied outbound instead of inbound.

Incorrect because the scenario says it is applied inbound.

Trap 2: The community value 100:100 is reserved and cannot be used.

Incorrect because 100:100 is a valid community value.

Trap 3: The route-map has a 'match community' statement that is filtering…

Incorrect because the scenario does not mention a match community statement.

A
The neighbor is missing the 'send-community' command under the BGP neighbor configuration.
Correct because communities are not exchanged without this command.
B
The route-map is applied outbound instead of inbound.
Why wrong: Incorrect because the scenario says it is applied inbound.
C
The community value 100:100 is reserved and cannot be used.
Why wrong: Incorrect because 100:100 is a valid community value.
D
The route-map has a 'match community' statement that is filtering the routes before the set command.
Why wrong: Incorrect because the scenario does not mention a match community statement.

Question 7mediummultiple choice

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A network engineer is troubleshooting a route filtering issue using distribute-lists under OSPF. Router R8 has a distribute-list out applied to the OSPF process to filter routes being advertised to a specific neighbor. The distribute-list references an ACL that denies a specific prefix, but the prefix is still being advertised to the neighbor. What is the most likely cause?

Trap 1: The ACL is using the wrong wildcard mask; it should deny the exact…

Incorrect because wildcard mask 0.0.0.0 matches only the exact prefix.

Trap 2: The distribute-list is applied inbound instead of outbound.

Incorrect because the scenario says it is applied outbound.

Trap 3: The OSPF process has 'default-information originate' that overrides…

Incorrect because default-information originate does not override distribute-lists.

A
The distribute-list is applied to the OSPF process, not to the specific neighbor; use 'neighbor distribute-list' instead.
Correct because per-neighbor filtering requires the distribute-list under the neighbor command.
B
The ACL is using the wrong wildcard mask; it should deny the exact prefix with 0.0.0.0 mask.
Why wrong: Incorrect because wildcard mask 0.0.0.0 matches only the exact prefix.
C
The distribute-list is applied inbound instead of outbound.
Why wrong: Incorrect because the scenario says it is applied outbound.
D
The OSPF process has 'default-information originate' that overrides the distribute-list.
Why wrong: Incorrect because default-information originate does not override distribute-lists.

Study the full ACL explanation →

Question 8hardmultiple choice

A network engineer is troubleshooting a PBR route-map that is supposed to set the next-hop for traffic from a specific source to a different next-hop. The route-map is applied to the incoming interface, and the ACL matches the traffic. However, the engineer notices that the traffic is still being forwarded using the routing table. The engineer checks the route-map and sees that the 'set ip next-hop' command points to an IP address that is not reachable. What is the most likely result?

Trap 1: The packet will be dropped because PBR cannot forward it.

Incorrect because PBR does not drop packets; it falls back to routing.

Trap 2: The router will send an ICMP unreachable message to the source.

Incorrect because the router will still forward the packet via the routing table.

Trap 3: The route-map will be ignored and all traffic will be dropped.

Incorrect because only the specific traffic matched will fall back to routing.

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A
PBR will fall back to the routing table and forward the packet normally.
Correct because PBR uses the routing table if the next-hop is unreachable.
B
The packet will be dropped because PBR cannot forward it.
Why wrong: Incorrect because PBR does not drop packets; it falls back to routing.
C
The router will send an ICMP unreachable message to the source.
Why wrong: Incorrect because the router will still forward the packet via the routing table.
D
The route-map will be ignored and all traffic will be dropped.
Why wrong: Incorrect because only the specific traffic matched will fall back to routing.

Question 9mediummultiple choice

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A network engineer is troubleshooting a BGP route-map that is supposed to prepend AS-path to routes from a specific neighbor. The engineer configures a route-map with 'set as-path prepend 65001' and applies it outbound to the neighbor. After the configuration, the engineer checks the BGP table on the neighbor and sees that the AS-path does not include the prepended AS. What is the most likely cause?

Trap 1: The AS 65001 is the same as the neighbor's AS, so BGP ignores the…

Incorrect because BGP allows prepending the same AS; it is a common practice.

Trap 2: The route-map is applied inbound instead of outbound.

Incorrect because the scenario says it is applied outbound.

Trap 3: The neighbor has 'soft-reconfiguration inbound' which prevents…

Incorrect because soft-reconfiguration does not affect outbound AS-path manipulation.

A
The route-map is missing a 'match' statement; without it, the set command is not applied to any routes.
Correct because a route-map without a match statement will not match any routes, so the set command is not executed.
B
The AS 65001 is the same as the neighbor's AS, so BGP ignores the prepend.
Why wrong: Incorrect because BGP allows prepending the same AS; it is a common practice.
C
The route-map is applied inbound instead of outbound.
Why wrong: Incorrect because the scenario says it is applied outbound.
D
The neighbor has 'soft-reconfiguration inbound' which prevents AS-path changes.
Why wrong: Incorrect because soft-reconfiguration does not affect outbound AS-path manipulation.

Question 10mediummultiple choice

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A network engineer runs the following command on Router R1:

R1# show route-map

route-map FILTER_OSPF, permit, sequence 10 Match clauses:

ip address prefix-list OSPF_ROUTES

Set clauses: Policy routing matches: 0 packets, 0 bytes route-map FILTER_OSPF, deny, sequence 20 Match clauses: Set clauses: Policy routing matches: 0 packets, 0 bytes

Based on this output, which statement is correct?

Trap 1: The route-map will permit all routes because sequence 20 has no…

A deny sequence without a match clause denies all unmatched routes.

Trap 2: The route-map is used for policy-based routing and has matched 0…

The counters show 0, but route-maps can be used for both PBR and route filtering; this output doesn't indicate usage.

Trap 3: The route-map will deny only routes matching the prefix-list…

Sequence 10 permits matching routes; sequence 20 denies others.

A
The route-map will permit all routes that match the prefix-list OSPF_ROUTES and deny all others.
Sequence 10 permits matching routes; sequence 20 denies everything else.
B
The route-map will permit all routes because sequence 20 has no match clause.
Why wrong: A deny sequence without a match clause denies all unmatched routes.
C
The route-map is used for policy-based routing and has matched 0 packets.
Why wrong: The counters show 0, but route-maps can be used for both PBR and route filtering; this output doesn't indicate usage.
D
The route-map will deny only routes matching the prefix-list OSPF_ROUTES.
Why wrong: Sequence 10 permits matching routes; sequence 20 denies others.

Question 11hardmultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip bgp neighbors 192.168.1.2 advertised-routes

BGP table version is 14, local router ID is 10.1.1.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path *> 10.10.10.0/24 192.168.1.2 0 0 65001 i *> 10.20.20.0/24 192.168.1.2 0 0 65001 i

Total number of prefixes 2

Based on this output, what is a likely issue?

Trap 1: The BGP session is down because there are no prefixes advertised.

The session is up as prefixes are advertised.

Trap 2: The router is not receiving updates from its peers.

The output shows advertised routes, not received routes.

Trap 3: The prefix-list is misconfigured and blocking all routes.

Two routes are advertised, so not all are blocked.

A
The neighbor 192.168.1.2 is not receiving all routes because a route-map is filtering them.
Only two prefixes are advertised; a route-map applied to the neighbor could be restricting the advertisement.
B
The BGP session is down because there are no prefixes advertised.
Why wrong: The session is up as prefixes are advertised.
C
The router is not receiving updates from its peers.
Why wrong: The output shows advertised routes, not received routes.
D
The prefix-list is misconfigured and blocking all routes.
Why wrong: Two routes are advertised, so not all are blocked.

Review the full routing breakdown →

Question 12mediummultiple choice

A network engineer runs the following command on Router R1:

R1# show ip policy
Interface   Route-map

FastEthernet0/0 PBR_MAP

R1# show route-map PBR_MAP

route-map PBR_MAP, permit, sequence 10 Match clauses:

ip address prefix-list MATCH_HTTP

Set clauses:

ip next-hop 10.10.10.2

Policy routing matches: 0 packets, 0 bytes

Based on this output, what is the most likely problem?

Trap 1: The route-map is not being applied to any interface.

show ip policy shows it is applied to FastEthernet0/0.

Trap 2: The next-hop 10.10.10.2 is unreachable.

The output does not indicate reachability; the match counter is 0.

Trap 3: The route-map is configured with the wrong sequence number.

Sequence 10 is valid and applied.

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A
The route-map is not being applied to any interface.
Why wrong: show ip policy shows it is applied to FastEthernet0/0.
B
The prefix-list MATCH_HTTP may not be matching any traffic, causing no policy routing.
0 packets matched indicates no traffic matches the prefix-list.
C
The next-hop 10.10.10.2 is unreachable.
Why wrong: The output does not indicate reachability; the match counter is 0.
D
The route-map is configured with the wrong sequence number.
Why wrong: Sequence 10 is valid and applied.

Study the full EIGRP explanation →

Question 13hardmultiple choice

A network engineer runs the following command on Router R1:

R1# show ip eigrp topology 10.10.10.0/24

IP-EIGRP (AS 100): Topology entry for 10.10.10.0/24 State is Passive, Query origin flag is 1, 1 Successor(s), FD is 131072 Routing Descriptor Blocks:

10.1.1.2 (FastEthernet0/0), from 10.1.1.2, Send flag is 0x0

Composite metric is (131072/128256), 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

R1# show ip route 10.10.10.0

Routing entry for 10.10.10.0/24 Known via "eigrp 100", distance 90, metric 131072, type internal Last update from 10.1.1.2 on FastEthernet0/0, 00:00:12 ago Routing Descriptor Blocks:

* 10.1.1.2, from 10.1.1.2, 00:00:12 ago, via FastEthernet0/0

Route metric is 131072, traffic share count is 1

R1# show ip eigrp interfaces
Interface         Peers    Xmit Queue   Mean   Pacing Time   Multicast    Pending

Un/Reliable SRTT Un/Reliable Flow Timer Routes Fa0/0 1 0/0 10 0/10 50 0 Fa0/1 0 0/0 0 0/10 50 0

Based on this output, what is a likely issue?

Trap 1: The route 10.10.10.0/24 is not in the routing table.

It is present in the routing table.

Trap 2: The EIGRP process is not running.

The process is running as shown by the topology entry.

Trap 3: The metric is too high for the route to be installed.

The route is installed with metric 131072.

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A
EIGRP neighbor on FastEthernet0/1 is not forming due to a route-map filtering updates.
FastEthernet0/1 has 0 peers, indicating no neighbor; a route-map could be blocking hello packets or updates.
B
The route 10.10.10.0/24 is not in the routing table.
Why wrong: It is present in the routing table.
C
The EIGRP process is not running.
Why wrong: The process is running as shown by the topology entry.
D
The metric is too high for the route to be installed.
Why wrong: The route is installed with metric 131072.

Question 14mediummultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip ospf database

OSPF Router with ID (10.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count

10.1.1.1        10.1.1.1        100         0x80000001 0x00A0B0 1
10.2.2.2        10.2.2.2        200         0x80000003 0x00C0D0 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum

10.1.1.2        10.1.1.2        150         0x80000001 0x00E0F0

R1# show ip route ospf
     10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
O       10.2.2.0/24 [110/20] via 10.1.1.2, 00:10:00, FastEthernet0/0

Based on this output, what is a likely issue?

Trap 1: OSPF is not running on any interface.

The database shows OSPF is running.

Trap 2: The router ID is misconfigured.

Router ID 10.1.1.1 is valid.

Trap 3: The area is not configured correctly.

Area 0 is standard.

A
A route-map is filtering OSPF routes, causing only one route to be installed.
The database has more routes than the routing table, indicating filtering.
B
OSPF is not running on any interface.
Why wrong: The database shows OSPF is running.
C
The router ID is misconfigured.
Why wrong: Router ID 10.1.1.1 is valid.
D
The area is not configured correctly.
Why wrong: Area 0 is standard.

Question 15hardmultiple choice

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A network engineer runs the following command on Router R1:

R1# show bgp ipv4 unicast 10.10.10.0/24

BGP routing table entry for 10.10.10.0/24, version 5 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 (10.2.2.2)

Origin IGP, metric 0, localpref 100, valid, external, best rx pathid: 0, tx pathid: 0x0 (received-only)

Based on this output, what does the "(received-only)" flag indicate?

Trap 1: The route is best and installed in the routing table.

The route is marked best but received-only indicates it is not installed.

Trap 2: The route is suppressed by a route-map.

Suppressed routes show 's' status, not received-only.

Trap 3: The route is being advertised to neighbors.

Advertised routes are shown in advertised-routes, not here.

A
The route is received but not installed in the routing table, likely due to a route-map filtering.
The received-only flag means the route is not used, often due to filtering.
B
The route is best and installed in the routing table.
Why wrong: The route is marked best but received-only indicates it is not installed.
C
The route is suppressed by a route-map.
Why wrong: Suppressed routes show 's' status, not received-only.
D
The route is being advertised to neighbors.
Why wrong: Advertised routes are shown in advertised-routes, not here.

Question 16mediummultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip bgp neighbors 192.168.1.2

BGP neighbor is 192.168.1.2, remote AS 65001, external link BGP version 4, remote router ID 10.2.2.2 BGP state = Established, up for 00:15:00 Last read 00:00:05, hold time is 180, keepalive interval is 60 seconds

Neighbor sessions:

1 active, is multisession capable

Neighbor capabilities:

Route refresh: advertised and received(new) Four-octets ASN: advertised and received Address family IPv4 Unicast: advertised and received Enhanced Refresh: advertised Message statistics: InQ depth is 0 OutQ depth is 0 Sent Rcvd Opens: 1 1 Notifications: 0 0 Updates: 10 5 Keepalives: 15 15 Route Refresh: 0 0 Total: 26 21 Default minimum time between advertisement runs is 30 seconds

For address family: IPv4 Unicast Session: 192.168.1.2 BGP table version 14, neighbor version 14/0 Output queue size : 0 Index 1, Advertise bit 0 1 update-group member Incoming update prefix filter list: FILTER_IN Outgoing update prefix filter list: FILTER_OUT Sent Rcvd Prefixes: 2 2 Updates: 10 5

Based on this output, what is the effect of the prefix lists?

Trap 1: The prefix lists are blocking all prefixes.

2 prefixes are being exchanged.

Trap 2: The prefix lists are not applied because the session is established.

The output shows they are applied.

Trap 3: The prefix lists are misconfigured and causing route flapping.

No evidence of flapping; session is stable.

A
The prefix lists FILTER_IN and FILTER_OUT are allowing only 2 prefixes in each direction.
The counters show 2 prefixes sent and received, matching the filter lists.
B
The prefix lists are blocking all prefixes.
Why wrong: 2 prefixes are being exchanged.
C
The prefix lists are not applied because the session is established.
Why wrong: The output shows they are applied.
D
The prefix lists are misconfigured and causing route flapping.
Why wrong: No evidence of flapping; session is stable.

Question 17hardmultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip route vrf CUSTOMER_A

Routing Table: CUSTOMER_A Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
B       10.10.10.0/24 [200/0] via 192.168.1.2, 00:10:00
B       10.20.20.0/24 [200/0] via 192.168.1.2, 00:10:00

R1# show ip bgp vpnv4 vrf CUSTOMER_A

BGP table version is 6, local router ID is 10.1.1.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path Route Distinguisher: 100:1 (default for vrf CUSTOMER_A) *> 10.10.10.0/24 192.168.1.2 0 0 65001 i *> 10.20.20.0/24 192.168.1.2 0 0 65001 i *> 10.30.30.0/24 192.168.1.2 0 0 65001 i

Based on this output, what is the likely issue?

Trap 1: The VRF is not properly configured.

The VRF is configured and has routes.

Trap 2: The BGP session is down.

Routes are present in BGP table.

Trap 3: The route distinguisher is misconfigured.

Route distinguisher 100:1 is consistent.

A
A route-map is filtering the route 10.30.30.0/24 from the VRF routing table.
BGP table has three routes, but routing table only has two, indicating filtering.
B
The VRF is not properly configured.
Why wrong: The VRF is configured and has routes.
C
The BGP session is down.
Why wrong: Routes are present in BGP table.
D
The route distinguisher is misconfigured.
Why wrong: Route distinguisher 100:1 is consistent.

Question 18hardmultiple choice

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A network engineer runs the following command on Router R1:

R1# show ip bgp neighbors 10.1.1.2 advertised-routes

BGP table version is 10, local router ID is 10.1.1.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter, x best-external, a additional-path, c RIB-compressed, Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path *> 10.10.10.0/24 0.0.0.0 0 32768 i *> 10.20.20.0/24 0.0.0.0 0 32768 i

R1# show route-map

route-map BLOCK_RFC1918, permit, sequence 10 Match clauses:

ip address prefix-list RFC1918

Set clauses: Policy routing matches: 0 packets, 0 bytes route-map BLOCK_RFC1918, deny, sequence 20 Match clauses: Set clauses: Policy routing matches: 0 packets, 0 bytes

R1# show ip prefix-list RFC1918
ip prefix-list RFC1918: 3 entries

seq 5 deny 10.0.0.0/8 le 32 seq

10 deny 172.16.0.0/12 le 32

seq

15 deny 192.168.0.0/16 le 32

seq

20 permit 0.0.0.0/0 le 32

Based on this output, what is the most likely issue?

Trap 1: The prefix-list RFC1918 is misconfigured and permits all routes.

The prefix-list denies RFC 1918 and permits others.

Trap 2: The route-map is applied but the match clause is incorrect.

The match clause references the prefix-list correctly.

Trap 3: The BGP session is not established.

Routes are being advertised, so session is up.

A
The route-map BLOCK_RFC1918 is not applied to the BGP neighbor, so RFC 1918 routes are being advertised.
The prefix-list denies RFC 1918, but the route-map is not applied to the neighbor, so routes are advertised.
B
The prefix-list RFC1918 is misconfigured and permits all routes.
Why wrong: The prefix-list denies RFC 1918 and permits others.
C
The route-map is applied but the match clause is incorrect.
Why wrong: The match clause references the prefix-list correctly.
D
The BGP session is not established.
Why wrong: Routes are being advertised, so session is up.

Question 19mediummultiple choice

Study all Route Maps and Route Filtering common traps →

Examine the following partial configuration on R1:

!--- R1 configuration route-map RMAP permit 10 match ip address prefix-list PL-1 set metric 100 ! route-map RMAP permit 20 set metric 200 !

router eigrp 100
 network 10.0.0.0

redistribute ospf 1 metric 1000 100 255 1 1500 route-map RMAP !

What is the effect of this configuration?

Trap 1: Only routes matching prefix-list PL-1 are redistributed into EIGRP…

Incorrect. The second permit sequence (20) with no match clause acts as a catch-all permit, so all routes are redistributed.

Trap 2: The route-map is missing a deny statement; without it, all routes…

Incorrect. A route-map without a deny statement still permits routes; the set actions apply as configured.

Trap 3: The route-map is applied to redistribution, but the metric values…

Incorrect. When a route-map is used with redistribute, the set metric in the route-map overrides the metric specified in the redistribute command.

A
Only routes matching prefix-list PL-1 are redistributed into EIGRP with metric 100; all other OSPF routes are denied.
Why wrong: Incorrect. The second permit sequence (20) with no match clause acts as a catch-all permit, so all routes are redistributed.
B
Routes matching prefix-list PL-1 are redistributed with metric 100; all other OSPF routes are redistributed with metric 200.
Correct. Sequence 10 matches PL-1 and sets metric 100; sequence 20 matches all other routes and sets metric 200.
C
The route-map is missing a deny statement; without it, all routes are permitted with default metric.
Why wrong: Incorrect. A route-map without a deny statement still permits routes; the set actions apply as configured.
D
The route-map is applied to redistribution, but the metric values are ignored because redistribute command also specifies metric.
Why wrong: Incorrect. When a route-map is used with redistribute, the set metric in the route-map overrides the metric specified in the redistribute command.

Question 20mediummultiple choice

Study all Route Maps and Route Filtering common traps →

Consider the following configuration on router R2:

!--- R2 configuration

ip prefix-list FILTER seq 5 deny 10.1.0.0/16 le 24
ip prefix-list FILTER seq 
10 permit 0.0.0.0/0 le 32

! route-map BGP-IN permit 10 match ip address prefix-list FILTER !

router bgp 65000
 neighbor 192.168.1.1 route-map BGP-IN in

What is the effect of this configuration?

Trap 1: All routes from neighbor 192.168.1.1 are accepted; the prefix-list…

Incorrect. The route-map uses the prefix-list; the deny statement in the prefix-list causes matching routes to be denied.

Trap 2: Only routes with mask length exactly 24 are denied; all other…

Incorrect. The 'le 24' means mask length less than or equal to 24, so /16, /17, etc., are also denied.

Trap 3: The configuration is incomplete; a route-map must have a deny…

Incorrect. A route-map can filter using a prefix-list that contains deny statements; the route-map itself only needs permit sequences.

A
All routes from neighbor 192.168.1.1 are accepted; the prefix-list is not applied correctly because the route-map only has a permit sequence.
Why wrong: Incorrect. The route-map uses the prefix-list; the deny statement in the prefix-list causes matching routes to be denied.
B
Routes within 10.1.0.0/16 with mask length 24 or shorter are denied; all other routes are permitted.
Correct. The prefix-list denies 10.1.0.0/16 le 24, which includes /16 to /24 subnets; all other prefixes are permitted.
C
Only routes with mask length exactly 24 are denied; all other routes are permitted.
Why wrong: Incorrect. The 'le 24' means mask length less than or equal to 24, so /16, /17, etc., are also denied.
D
The configuration is incomplete; a route-map must have a deny statement to filter routes.
Why wrong: Incorrect. A route-map can filter using a prefix-list that contains deny statements; the route-map itself only needs permit sequences.