Cisco CCNP Enterprise 300-410 Questions & Answers

• Question 561:

  Examine the exhibit.

  

  You are asked to configure the routers R1, R2, R3, and R4. (Refer to the IP addressing table below.) Which configuration command series is required to ensure that router R1 will NOT be receiving Type 3, 4, or 5 LSAs?

  R1 interface E0 - 172.31.200.1/21 R2 interface E0 - 172.31.200.2/21 R2 interface E1 - 172.31.208.2/21 R3 interface E0 - 172.31.208.3/21

  A. R1(config)# router ospf 5 R1(config-router)# area 5 stub R1(config-router)# network 172.31.200.0 0.0.7.255 area 5

  B. R2(config)# router ospf 5 R2(config-router)# area 5 stub no-summary R2(config-router)# network 172.31.200.0 0.0.7.255 area 5 R1(config)# router ospf 5 R1(config-router)area 5 stub R1(config-router)# network 172.31.200.0 0.0.7.255 area 5

  C. R1(config)# router ospf 10 R1(config-router)# area 5 stub R1(config-router)# network 172.31.200.0 255.255.248.0 area 5

  D. R2(config)# router ospf 10 R2(config-router)# area 5 stub no-summary R2(config-router)# network 172.31.200.0 255.255.248.0 area 5

  Correct Answer: B

  At the area border router (ABR), router R2, the no-summary keyword is required with the area stub command to create a totally stubby area. All other routers in area 5 will require the stub command without the no summary keyword. The following commands are required to configure R2:

  R2(config)# router ospf 5 R2(config-router)# area 5 stub no-summary R2(config-router)# network 172.31.200.0 0.0.7.255 area 5

  R1 will require:

  R1(config)# router ospf 5 R1(config-router)# area 5 stub R1(config-router)# network 172.31.200.0 0.0.7.255 area 5

  All routers within a stub area must be configured as stub, or adjacencies will not form. Besides the command to enable OSPF and the command to identify the area, the only other required command identifies the area as a stub. A totally stubby area does not accept any external network LSAs (Type 5) or any inter-area summary LSAs (Types 3 and 4) from entering the area.

  Use the area stub command with the no-summary keyword to configure a totally stubby area. The diagram below shows the commands that should be executed on R1 and R2.

  

  The correct syntax for the area stub command is shown below: Router(config-router)# area area-id stub [no-summary]

  Note that the optional no-summary keyword is used only on area border routers (ABRs) to block summary link advertisements into the stub area. This option creates a totally stubby area. It is very important to configure the command

  consistently on all routers within the area. OSPF sends its stub status (on or off) in its hello packets. If two neighbors have conflicting stub status, they will not form an adjacency, and you end up with no OSPF communication over that link.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify network types, area types, and router types

  References:

  Cisco > Home > Support > Technology Support > IP Routing > Design > Design Technotes > What Are OSPF Areas and Virtual Links? > What Are Areas, Stub Areas, and Not-So-Stubby Areas? Cisco > Cisco IOS IP Routing: OSPF

  Command Reference > area stub

• Question 562:

  Refer to the following partial output of the show ip bgp neighbors command:

  

  Which of the following can NOT be determined from the given output? (Choose all that apply.)

  A. The ASN of rtrA

  B. The ASN of 172.161.81.7

  C. The best paths between rtrA and the 172.161.81.7 neighbor

  D. The RID of the 172.161.81.7 neighbor

  E. The status of the connection between rtrA and 172.161.81.7

  Correct Answer: AC

  The autonomous system number (ASN) of rtrA and the best paths between rtrA and the 172.161.81.7 neighbor cannot be determined from the given output.

  The show ip bgp neighbors command displays the TCP and BGP connections from a given router to its neighbors. This command is executed in EXEC mode. You can use various optional keywords to view different aspects of the neighbors. For example, this command can display the details about a given neighbor, routes advertised to or received from neighbors, and the prefix-list received by neighbors.

  In this case, the command is used to show the details about a specific neighbor of rtrA. The IP address (172.161.81.7) of the neighbor is provided in the command. The text BGP neighbor is 172.161.81.7 indicates the IP address of the neighbor. The text remote AS 151 indicates that the neighbor is in the ASN 151. It can also be determined from the text external link that the neighbor is an eBGP neighbor. For iBGP neighbors, the text internal link will appear. The router ID (RID) of the neighbor can be determined from the text remote router ID 10.8.22.4. The output also provides details about the state of the BGP connection, which is Established in this case. Furthermore, the duration for which the connection has been established, the duration for which BGP maintains neighbor relationship in the absence of messages, and the keepalive duration are also displayed.

  The state of the connection between the local router (rtrA) and the given neighbor (172.161.81.7) can be any of the following: Idle Indicates that the local router does not accept any connection from its neighbor Idle (admin) Indicates that the connection between the two routers has been shut down administratively by using the neighbor shutdown command Connect Indicates that the local router has already sent an connection request to its neighbor Active Indicates that the local router is listening for connection requests from the neighbor OpenSent Indicates that the local router has sent an OPEN message to its neighbor OpenConfirm Indicates that the local router has received a KEEPALIVE or UPDATE message from its neighbor Established Indicates that a BGP connection has been successfully created between the local router and its neighbor

  The status of the connection between two BGP neighbors can also be viewed by using the show ip bgp summary command, as shown below:

  

  In the above output, it can be determined that the command router bgp 210 was executed on rtrA because the local AS is 210 in the output. It can be determined that the command neighbor 45.1.1.5 shutdown was issued on rtrA because the

  state of the neighbor relationship with the router at 45.1.1.5 is listed as IDLE(ADMIN).

  All the other options are incorrect because the respective details are displayed by the show ip bgp neighbors command.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify eBGP (IPv4 and IPv6 address families)

  References:

  Cisco IOS IP Routing: BGP Command Reference > show ip bgp neighbors Cisco > Cisco IOS IP Routing: BGP Command Reference > show ip bgp summary

• Question 563:

  Router10 is an area system border router (ASBR). The interfaces on Router 10 are configured as below:

  S 0/0 10.0.0.0/8 S0/1 172.16.0.0/8 Fa0/0 192.168.5.0/24 Fa0/1 192.168.6.0/24

  You would like Router 10 to advertise the 192.168.5.0/24 and the 192.168.6.0/24 networks over OSPF in its Type 5 link-state advertisements (LSAs).

  What command set would instruct the router to do this?

  A. RTA10(config)# router ospf 1 RTA10(config-router)# redistribute static

  B. RTA10(config)# router ospf 1 RTA10(config-router)# redistribute connected

  C. RTA10(config)# router ospf 1 RTA10(config)# redistribute connected

  D. RTA10(config)# router ospf 1 RTA10(config-router)# network 192.168.5.0 0.0.0.0 area 1 RTA10(config-router)# network 192.168.6.0 0.0.0.0 area 1

  Correct Answer: B

  By default, Type 5 link-state advertisements (LSAs) do not include directly connected networks. To alter this behavior, you must execute the redistribute connected command in OSPF configuration mode. This command instructs the router to

  include these local interfaces in its advertisements, as follows:

  RTA10(config)# router ospf 1

  RTA10(config-router)# redistribute connected

  You should not execute the command set that includes the redistribute static command. This instructs the router to advertise any statically defined routes that have been configured, instead of those that are local to the router.

  You should not execute the command set that includes RTA10(config)# redistribute connected. The redistribute connected command is shown being executed at the wrong command prompt, and will generate an error message. It must be

  executed in the OSPF configuration mode and not global configuration mode.

  You should not execute the following command set:

  RTA10(config)# router ospf 1

  RTA10(config-router)# network 192.168.5.0 0.0.0.0 area 1

  RTA10(config-router)# network 192.168.6.0 0.0.0.0 area 1

  The network commands will cause the networks to receive updates from the router, but do not allow them to be advertised in Type 5 LSAs.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify redistribution between any routing protocols or routing sources

  References:

  Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > Redistributing Connected Networks into OSPF

• Question 564:

  Which show command displays the status of all of a router's Border Gateway Protocol (BGP) connections in a concise format?

  A. show ip bgp

  B. show ip bgp summary

  C. show ip bgp connections

  D. show ip bgp neighbor's summary

  Correct Answer: B

  The correct answer is show ip bgp summary.

  Although show ip bgp neighbors will show you the status of your connections to neighbors, only show ip bgp summary shows it to you in a concise, summarized format, with one neighbor listed per line. It displays both iBGP and eBGP neighbors and the number of prefixes that have been learned from the neighbor. Below is an example of the output of the show ip bgp summary command:

  

  The following information can be obtained from this output:

  The BGP session to 192.168.5.1 is established. A number in the State column indicates that the session is established. This number indicates the number of prefixes received from the neighbor. Router6 is attempting to establish a BGP

  peering session with the 192.168.6.1 neighbor. This is indicated by the keyword Active in the State column.

  Several show commands can be used to verify BGP configuration and operation:

  show ip bgp - displays the contents of the BGP routing table show ip bgp summary - displays the status of BGP connections in a summary format show ip bgp neighbors - displays information about the TCP and BGP connections to neighbors

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Describe, configure, and verify BGP peer relationships and authentication

  References:

  Cisco IOS Master Command List, Release 12.4 > a through b > BGP > Commands: show ip through T > show ip bgp summary

• Question 565:

  Examine the following diagram:

  

  Routing updates are not being received on Router A from Router D. The partial output of the show run command for Router B and Router C is shown below:

  

  What commands should you run to ensure that routing updates are getting to Router A from Router D? (Choose all that apply.)

  A. routerC(config-router)# area 1 virtual-link 2.2.2.2

  B. routerC(config-router)# no area 1 virtual-link 4.4.4.4 routerC(config-router)# area 0 virtual-link 2.2.2.2

  C. routerB(config-router)# area 0 virtual-link 3.3.3.3

  D. routerB(config-router)# area 1 virtual-link 3.3.3.3

  E. routerC(config-router)# no area 1 virtual-link 4.4.4.4 routerC(config-router)# area 1 virtual-link 2.2.2.2

  F. routerB(config-router)# area 1 virtual-link 4.4.4.4

  G. routerB(config-router)# no area 1 virtual-link 4.4.4.4

  Correct Answer: DE

  The problem is that the virtual link that provides a connection from area 2 to area 0 is misconfigured on Router C, and is missing entirely from Router B. The current configuration on Router C uses the router ID 4.4.4.4 in the virtual link statement, but the neighbor that is on the other end of the link (Router B) has an ID of 2.2.2.2. Therefore, you must remove the incorrect statement with this command:

  routerC(config-router)# no area 1 virtual-link 4.4.4.4

  Then, you would recreate it correctly with the following command:

  routerC(config-router)# area 1 virtual-link 2.2.2.2

  The configuration of the virtual link on Router B is missing completely. To add it, you would use the area 1 virtual-link command and configure the neighbor as Router C at 3.3.3.3:

  routerB(config-router)# area 1 virtual-link 3.3.3.3

  You should not run the following command on Router C:

  routerC(config-router)# area 1 virtual-link 2.2.2.2

  This would apply a correct statement, but leave in the incorrect statement.

  You should not run any of the following sets of commands:

  routerC(config-router)# no area 1 virtual-link 4.4.4.4

  routerC(config-router)# area 0 virtual-link 2.2.2.2

  or

  routerB(config-router)# area 0 virtual-link 3.3.3.3

  These commands all incorrectly include the area 0 syntax. The area in the command should be the area being transited to get to area 0, which is area 1.

  You should not run the routerB(config-router)# area 1 virtual-link 4.4.4.4 command on Router B. This command uses an incorrect router ID. The neighbor for Router B should be Router C, 3.3.3.3

  You should not run the routerB(config-router)# no area 1 virtual-link 4.4.4.4 command on Router B. There is no virtual link to remove from Router B.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify network types, area types, and router types

  References:

  Home>Support>Technology Support>IP>IP Routing>Configure>Configuration Examples and Technotes>OSPF virtual link

  Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > What Are OSPF Areas and Virtual Links?

• Question 566:

  Which of the following does the show ip eigrp topology all-links command display?

  A. Only feasible successors

  B. Only non-feasible successors

  C. Both feasible successors and non-feasible successors

  D. Both successors and feasible successors

  Correct Answer: C

  The show ip eigrp topology all-links command displays both the feasible successors and the non-feasible successors. Feasible successors refer to backup routes to a particular destination network.

  Routers compute the metric/distance of every route they learn from their EIGRP neighbors. There can be multiple routes to the same destination network. The route with the least metric value to a specific destination network is selected as the best path, or successor, to that network. However, if the successor goes down, the router computes the next best loop-free path to the same destination network, which is called the feasible successor.

  Feasible successors must have a reported (or advertised) distance that is less than the feasible distance, or current best metric. The routes that are neither successors nor feasible successors are called non-feasible successors. The feasible successors and the non-feasible successors can be viewed by running the show ip eigrp topology all-links command. Sample output is shown below:

  

  The router at 172.17.3.1 is directly connected to three networks: 172.25.1.0/24, 172.20.2.0/24, and 172.18.2.0/24. The second network, 172.20.2.0/24, is listed as the source of the successor routes to those networks. The connection to the

  last network, 172.18.2.0/4, can deduced by the fact that the local router uses the Serial1 interface to connect to the two networks that the router at 172.17.3.1 is a successor for. Therefore, that router must be directly connected to the network

  on the Serial1 interface of the local router.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify policy-based routing

  References:

  Cisco IOS IP Routing: EIGRP Command Reference > show ip eigrp topology

• Question 567:

  You can use a variety of commands to verify and troubleshoot the operation of route redistribution on your network.

  Which command should you NOT use on routers that are overloaded?

  A. trace

  B. debug

  C. show ip route

  D. show ipx route

  Correct Answer: B

  The debug command uses a good deal of router CPU time, so you should not initiate this command on an already overloaded router. It often requires the router to do extensive examination of the packets, requiring heavy use of resources at

  times.

  You could also possibly overload the router just with the debug command. If the router is overloaded to the point that it is no longer responding to your EXEC session, you may need to reload the router to stop the debug output.

  These additional steps can help to verify proper route redistribution:

  On the router not performing the redistribution, use the show ip route command to see if the redistributed routes are displayed. On the router performing the redistribution, use the show ip protocol command to verify the redistribution

  configuration, and use the show ip route command that to verify the proper routes are there from each routing protocol.

  The trace command is used to discover the route that packets take to their destination.

  The show ip route command displays the routing table.

  The show ip protocols command displays information about each routing protocol running on the router.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify manual and autosummarization with any routing protocol

  References:

  Cisco > Home > Support > Technology Support > Dial and Access > ISDN, CAS > Design > Design Technotes > Important Information on Debug Commands > Document ID: 10374 Cisco > Cisco IOS Debug Command Reference > Using

  Debug Commands

• Question 568:

  You instructed your associate to configure Router R2 to reject a redistribution of the 20.0.0.0/8 network, while still receiving routes from other networks connected to Router R1. The diagram below displays the network in place:

  

  When he is finished, you find that the 20.0.0.0/8 network still being advertised and traffic from the 20.0.0.0/8 network is not reaching Router2. You execute the show running-configuration command and see the following output:

  

  What is the problem?

  A. The access list was applied to the wrong interface.

  B. The access list should have been configured as a distribute list.

  C. The access list has an incorrect wildcard mask.

  D. The access list is applied in the wrong direction.

  Correct Answer: B

  The access list should have been created as a distribute list to control route redistribution from the other area. This configuration would prevent the redistribution of the 20.0.0.0/8 network by applying the list as a distribute list under the Border

  Gateway Protocol (BGP). The proper commands would be:

  Router2(config)# router bgp 94688

  Router2(config-router)# distribute-list 101 in

  To correct the problem with traffic not arriving from the 20.0.0.0/8 network, you must remove the application of the list under interface S0 as well. This would be done by executing the following command set:

  Router2(config)# interface Serial1

  Router2(config-int)# no ip access-group 101 in

  The access list was not applied to the wrong interface. It should not have been applied directly to any interface. When applied directly as an access list to an interface, it will prevent traffic, but not the redistribution of routes.

  The access list does not have an incorrect wildcard mask. To prevent the redistribution of a Class C network, the correct wildcard mask is 0.0.0.255.

  The access list was not applied in the wrong direction. It should be applied incoming, but should be applied as an incoming distribute list, and it should be applied under the BGP protocol.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify filtering with any protocol

  References:

  Cisco IOS Master Command List, Release 12.4T > d > distribute-list in (IP) Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > Filtering Routing Updates on Distance Vector IP Routing Protocols

• Question 569:

  You manage the company network, as shown in the network diagram below:

  

  You executed the following command on RouterA:

  routerA(config)# ip route 0.0.0.0 0.0.0.0 S0/0 routerA(config)# router eigrp 200 routerA(config-router)# redistribute static metric 1000 1 255 1 1500

  Which of the following statements are TRUE about the given set of commands? (Choose two.)

  A. A static default route is created on RouterA

  B. A summary default route is created on RouterA

  C. The default route is redistributed into the EIGRP network

  D. The default route is not advertised to the EIGRP network

  Correct Answer: AC

  The given set of commands creates a static default route on RouterA and redistributes this route into the EIGRP company network. The ip route 0.0.0.0 0.0.0.0 S0/0 command executed in the global configuration mode creates a static default route on the router. The ip route command allows you to specify a static route. The redistribute static metric 1000 1 255 1 1500 command then redistributes the static default route into the EIGRP autonomous system (AS) 200. This implies that the EIGRP network identifies the default route as an external route, and traffic to all unknown destination subnets will be diverted to the default route.

  Alternatively, default routes can be advertised into EIGRP networks by either of the following methods: Using the network 0.0.0.0 command on the router Using the ip summary-address eigrp 200 0.0.0.0 0.0.0.0 command on the router

  A summary default route is not created on RouterA in the scenario. If the ip summary-address eigrp 200 0.0.0.0 0.0.0.0 command was used on RouterA, then a summary default route would be created. The summary default route points to the

  0.0.0.0 network with the null0 interface as the next-hop interface. Summary default routes are helpful for providing remote networks with a default route.

  The default route is advertised to the EIGRP network because the redistribute command was executed. This command is used to advertise the default route to the EIGRP network.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify default routing

  References:

  Cisco > Support > Technology Support > IP > IP Routing > Design > Design TechNotes > Configuring a Gateway of Last Resort Using IP Commands Cisco > Support > Technology Support > IP > IP Routing > Technology Information >

  Technology White Paper > Enhanced Interior Gateway Routing Protocol

• Question 570:

  Which commands will display the feasible successors, the feasible distance, and the advertised distance for networks learned by a router?

  A. show ip eigrp topology

  B. show ip route

  C. show bgp neighbors

  D. show ip eigrp traffic

  E. show ip route eigrp

  Correct Answer: A

  To view the feasible successors, the feasible distance, and the advertised distance, you would use the show ip eigrp topology command. A sample output of this command is below.

  

  The table lists all routes to networks and their advertised distance and feasible distance. This information is used to select the successor and feasible successor for each network. Before a route can be considered as a feasible successor or

  backup, the feasible distance of the route must be a larger value than the advertised distance.

  The following information can be extracted from this output:

  The route 15.10.0.0/16 has a feasible successor. If you examine the feasible and advertised distances in the brackets next to the two potential feasible successor routes [feasible distance/advertised distance], you will see that for the route

  15.10.0.0/16 via 10.10.5.1, the feasible distance of the route is greater (2594586) than the advertised distance (2448152), which qualifies it as a feasible successor. The route 65.0.0.0/8 does not have a feasible successor. The route

  65.0.0.0/8 via 10.20.1.6 has a feasible distance (2589779) that is less than the advertised distance (2672569), so it does not qualify.

  The router at 10.20.0.1 is directly connected to the networks 65.0.0.0/8 and 150.10.0.0/16. This can be deduced by the fact that the address 10.20.0.1 is the source of the successor routes for those networks. The route to 200.10.10.0/24 is

  undergoing recomputation, as evidenced by the line FD is Inaccessible. It also tells you that Router2 sent a query to 10.1.1.2 and is waiting for a reply, as evidenced by the line Remaining replies: via 10.1.1.2, r, Serial 0. The route to the

  10.0.0.0/8 network is showing a convergence problem, as evidenced by the code SIA to the left of its entry. This stands for Stuck In Active. An active state is present when the local router has queried for a new route to the network. Stuck in

  Active occurs when no response has been received, and the local router marks it SIA.

  The show ip route and the show ip route eigrp commands simply display the routing table, which does not display the advertised distance. Below is an example of the show ip route command executed on a router running EIGRP:

  

  The show ip eigrp traffic command does not show feasible successors, feasible distance or advertised distance. It displays statistics on hellos, updates, queries, replies and acknowledgments. Sample output is shown below:

  Router# show ip eigrp traffic

  IP-EIGRP Traffic Statistics for process 100

  Hellos sent/received: 215/212

  Updates sent/received: 7/25

  Queries sent/received: 2/0

  Replies sent/received: 0/2

  Acks sent/received: 21/17

  The show ip bgp command displays information involving BGP and has nothing to do with EIGRP.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify policy-based routing

  References:

  Cisco IOS IP Routing: EIGRP Command Reference > show ip eigrp topology