Cisco 300-410 Online Practice Questions and Exam Preparation

Cisco 300-410 Online Questions & Answers

• Question 351:

  An OSPF area contains the following networks:

  165.164.8.0 255.255.254.0

  165.164.10.0 255.255.254.0

  165.164.12.0 255.255.254.0

  165.164.14.0 255.255.254.0

  How can the route to these networks be summarized?

  A. 165.164.8.0 255.255.240.0
  B. 165.164.8.0 255.255.248.0
  C. 165.164.10.0 255.255.252.0
  D. 165.164.14.0 255.255.240.0
  B. 165.164.8.0 255.255.248.0

  ---

  Summarization is the process of advertising a network with a subnet mask such that it includes all of the subnets. For a simple example if you had two Class C networks, you could advertise them as a Class B network and it would encompass them both. Normally summarization should be implemented such that it summarizes ONLY the networks desired and no others (in the simple example it would possibly include other Class C networks). The process for arriving at the "best" summarization is a follows.

  First, write the last octet that all networks share in common (third octet in this case) in binary form for each network:

  165.164.8.0--00001000

  165.164.10.0--00001010 165.164.12.0--00001100 165.164.14.0--00001110

  The addresses have the first five bits in common; therefore, they can be summarized with the third octet 00001000 and a subnet mask of 255.255.248.0.

  Another way of looking at it is that 165.164.8.0 255.255.248.0 covers the range of 165.164.8.0 through 165.164.15.255, the same range as all the component subnets.

  None of the following possible answers is a valid range, nor do most of them cover the correct range of addresses:

  165.164.8.0 255.255.240.0 is not a valid range. A 20-bit mask can only be on a subnet that is a multiple of 16, such as .16.0, .32.0, .48.0 etc. The subnet .8.0 is not a multiple of 16.

  165.164.10.0 255.255.252.0 is not valid. A 22-bit mask requires a multiple of 4 in the third octet, and 10 is not a multiple of four. Even if it were a valid range, it does not cover the entire range of addresses that need to be summarized.

  165.164.14.0 255.255.240.0 is not valid. The 20-bit mask is only usable on ranges that are multiples of 16 in the third octet, and 14 is not a multiple of 16. Even if the mask were valid, it could not cover the correct addresses.

  When addresses are summarized the cost of the summary address will the highest cost of the component subnets. For example, in the partial sample output of the show ip route command below, there are three routes. The output is from a router running OSPFv3, so the addresses are IPv6, but the concept is the same.

  OI 2001:0D B 8:0:0:7/64 [110/20]

  via FE 80::A8BB:CCFF:FE 00:6F00, FastEthernet0/0

  OI 2001:0D B 8:0:0:8/64 [110/100]

  via FE 80::A8BB:CCFF:FE 00:6F00, FastEthernet0/0

  OI 2001:0D B 8:0:0:9/64 [110/40]

  via FE 80::A8BB:CCFF:FE 00:6F00, FastEthernet0/0

  The routes have metrics (the second value in brackets, [administrative distance/cost]) of 20, 100, and 40. Therefore, the metric for the summarized route would be 100.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify manual and autosummarization with any routing protocol

  References:

  Cisco > Home > Support > Technology Support > IP Routing > Technology > Information Technology > White Papers > OSPF Design Guide

• Question 352:

  Refer to the exhibit. Which action resolves the authentication problem?

  

  A. Configure the user name on the TACACS+ server
  B. Configure the UDP port 1812 to be allowed on the TACACS+ server
  C. Confiqure the TCP port 49 to be reachable by the router
  D. Configure the same password between the TACACS+ server and router.
  D. Configure the same password between the TACACS+ server and router.

  ---

  From the last line of the output, we notice that the result was "Invalid AUTHEN packet". Therefore something went wrong with the username or password.

• Question 353:

  A time based access list has been configured on R1 to allow SSH access to the device only on weekdays. Which of the following are valid options when using the time range command? (Choose two.)

  A. relative
  B. recurring
  C. absolute
  D. periodic
  C. absolute
  D. periodic

• Question 354:

  Which protocol does MPLS use to support traffic engineering?

  A. Tag Distribution Protocol
  B. Resource Reservation Protocol (RSVP)
  C. Border Gateway Protocol
  D. Label Distribution Protocol
  B. Resource Reservation Protocol (RSVP)

  ---

  MPLS TE provides a way to integrate TE capabilities (such as those used on Layer 2 protocols like ATM) into Layer 3 protocols (IP). MPLS TE uses an extension to existing protocols (Intermediate System-to- Intermediate System (IS-IS), Resource Reservation Protocol (RSVP), OSPF) to calculate and establish unidirectional tunnels that are set according to the network constraint, Traffic flows are mapped on the different tunnels depending on their destination.

• Question 355:

  Which conditions will prevent two EIGRP routers from becoming neighbors? (Choose two.)

  A. Their K-values do not match.
  B. Their hold times do not match.
  C. Their AS numbers do not match.
  D. Their hello intervals do not match.
  A. Their K-values do not match.
  C. Their AS numbers do not match.

  ---

  EIGRP routers will not become neighbors if the K-values do not match or if the autonomous system (AS) numbers do not match. They also will not become neighbors if EIGRP is not enabled for the proper networks on the local and remote routers. However, routers can become neighbors if their hello intervals and hold times do not match.

  The AS number is designed to control the routers with which a router can communicate. If the AS numbers do not match, EIGRP will not exchange routes between the two routers by design and definition.

  The K-values are flags that state whether a certain metric component, such as Load, is used. They must match because they regulate how the metric values are calculated. If one router is just using bandwidth and delay to calculate its metric, and another is using bandwidth, delay, and load; they could make contradictory routing decisions that would lead to a routing loop. Because of this possibility, EIGRP requires that the K- values must match before it will allow the routers to exchange routes.

  EIGRP does not require that the hello and hold times match. Although this flexibility can be helpful, it can also lead to unforeseen problems if they are accidentally mismatched. The hello interval is the amount of time in seconds to wait before sending another hello packet. The hold time is the amount of time in seconds to wait before declaring a link to be down.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify EIGRP neighbor relationship and authentication

  References:

  Cisco > Home > Support > Technology Support > IP > IP Routing > Design > Design Technotes > Introduction to EIGRP > How does EIGRP work?

• Question 356:

  Refer to the exhibit.

  

  An engineer has configured policy-based routing and applied the configured to the correct interface. How is the configuration applied to the traffic that matches the access list?

  A. It is dropped
  B. It is forwarded using the routing table lookup
  C. It is sent to 209.165.202.131.
  D. It is sent to 209.165.202.129.
  C. It is sent to 209.165.202.131.

  ---

  The set ip next-hop verify-availability command in route-map configuration mode to configure policy routing to verify the reachability of the next hop of a route map before the router performs policy routing to that next hop. In this question we see track 100 is down so the PBR will not use this next-hop, it will use the second next-hop with track 200 (up).

• Question 357:

  Click the Exhibit(s) button to view an EIGRP network. The partial output of the show running-config command on the rtrB router is as follows:

  

  Which of the following subnets are blocked through the Fa0/0 interface of rtrB while sending updates to rtrC? (Choose all that apply.)

  A. 172.161.9.0/24
  B. 172.161.35.0/18
  C. 172.161.64.0/28
  D. 172.161.88.0/22
  E. 172.161.111.0/25
  F. 172.161.247.0/30
  A. 172.161.9.0/24
  E. 172.161.111.0/25
  F. 172.161.247.0/30

  ---

  The 172.161.9.0/24, 172.161.111.0/25 and 172.161.247.0/30 subnets are blocked through the Fa0/0 interface of rtrB while sending updates to rtrC. The following lines in the output create an IP prefix list named blk_A:

  ip prefix-list blk_A deny 172.161.0.0/16 ge 24 le 30

  ip prefix-list blk_A permit 0.0.0.0/0 le 32

  The blk_A list blocks the subnets that exactly match the first 16 most significant bits as 172.161.0.0. The ge keyword indicate that the subnet mask for the 172.161.0.0 subnets must be greater than or equal to 24 bits. Similarly, the le keyword indicates that the mask for the 172.161.0.0 subnets should be less than or equal to 30 bits. Therefore, all subnets of 172.161.0.0 network with masks 24, 25, 26, 27, 28, 29, and 30 are blocked.

  The second line permits all other routes to be passed on. The subnets that match the blk_A prefix list are 172.161.9.0/24, 172.161.111.0/25, 172.161.247.0/30, and 172.161.64.0/28.

  The line distribute-list prefix blk_A out indicates that the distribute-list command applies the blk_A prefix list to all the outgoing interfaces. This implies that if rtrB receives an update about the 172.161.9.0/24, 172.161.111.0/25, 172.161.247.0/30 or 172.161.64.0/28 subnets, they are blocked. In this case, the 172.161.64.0/28 is not blocked through the Fa0/0 interface to rtrC because it is directly connected.

  The 172.161.35.0/18 and 172.161.88.0/22 subnets are not blocked through the Fa0/0 interface of rtrB to rtrC. This is because both these subnets are outside the range of prefix masks 24 through 30; hence, these two subnets are allowed through the Fa0/0 interface.

  Objective:

  Layer 3 Technologies

  Sub-Objective:

  Configure and verify filtering with any protocol

  References:

  Cisco > Home > Support > Technology Support > IP > IP Routing > Technology Information > Technology Technotes > Filtering Routing Updates on Distance Vector IP Routing Protocols Cisco > Cisco IOS IP Routing: Protocol-Independent Command Reference > distribute-list in Cisco > Cisco IOS IP Routing: BGP Command Reference > ip prefix-list

• Question 358:

  Refer to the exhibit. After applying IPsec, the engineer observed that the DMVPN tunnel went down, and both spoke-to-spoke and hub were not establishing. Which two actions resolve the issue? (Choose two.)

  

  A. Change the mode from mode tunnel to mode transport on R3.
  B. Remove the crypto isakmp key cisco address 10.1.1.1 on R2 and R3.
  C. Configure the crypto isakmp key cisco address 192.1.1.1 on R2 and R3.
  D. Configure the crypto isakmp key cisco address 0.0.0.0 on R2 and R3.
  E. Change the mode from mode transport to mode tunnel on R2.
  B. Remove the crypto isakmp key cisco address 10.1.1.1 on R2 and R3.
  D. Configure the crypto isakmp key cisco address 0.0.0.0 on R2 and R3.

• Question 359:

  Refer to the exhibit.

  

  AAA server 10.1.1.1 is configured with the default authentication and accounting settings, but the switch cannot communicate with the server

  Which action resolves this issue?

  A. Match the authentication port
  B. Match the accounting port
  C. Correct the timeout value.
  D. Correct the shared secret.
  A. Match the authentication port

  ---

  Command Default Accounting port: 1813 Authentication port: 1812 Accounting: enabled Authentication: enabled Retransmission count: 1 Idle-time: 0 Server monitoring: disabled Timeout: 5 seconds Test username: test Test password: test

  Reference https://www.cisco.com/c/m/en_us/techdoc/dc/reference/cli/n5k/commands/radius-server-host.html

• Question 360:

  What is the purpose of the DHCPv6 Guard?

  A. It messages between a DHCPv6 server and a DHCPv6 client (or relay agent).
  B. It shows that clients of a DHCPv6 server are affected.
  C. It blocks DHCPv6 messages from relay agents to a DHCPv6 server.
  D. It allows DHCPv6 reply and advertisements from (rogue) DHCPv6 servers.
  C. It blocks DHCPv6 messages from relay agents to a DHCPv6 server.

  ---

  https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6_fhsec/configuration/xe-16/ip6fxe-16-book/ip6-dhcpv6-guard.html