Cisco 642-902 Online Practice Questions and Exam Preparation

Cisco 642-902 Online Questions & Answers

• Question 211:

  During the IPv6 auto configuration, what does the device append to the 64-bit prefix that it receives from the router to create its IPv6 address?

  A. a pseudorandom generated number
  B. its locally configured IPv4 address
  C. the DHCP-supplied device ID
  D. its MAC address
  D. its MAC address

  ---

  The automatic configuration is a great feature of IPv6. Imagine you have to manually configure an IPv6 address with 128-bit long, what a pain! With this feature, it is no longer necessary to configure each host manually. But notice that host only autonomously configures its own Link-local address (the IP address used on a LAN). The Link-local address can be created automatically using a link-local prefix of FE80::/10 and a 64-bit interface identifier (based on 48-bit MAC address).

  For example, if your MAC address is 00:12:34:56:78:9a, your 64-bit interface identifier is 0012:34FF:FE56:789a (16-bit FFFE is inserted in the middle). And notice that the notation has been changed because IPv6 addresses require 16-bit

  pieces to be separated by ":".

  Then, according to the RFC 3513 we need to invert the Universal/Local bit ("U/L" bit) in the 7th position of the first octet (start counting from 0). The "u" bit is set to 1 to indicate Universal, and it is set to zero (0) to indicate local scope. In this

  case we set this bit to 1 because the MAC address is universally unique. Thus the result is: 0212:34FF:FE56:789a.

  Finally, add the link-local prefix FE80 to create the full IPv6 address:

  FE80:0:0:0:0212:34FF:FE56:789a (or FE80::212:34FF:FE56:789a, in short form).

  Note: The reason for inverting the "U/L" bit is to allow ignoring it for short values in the manual configuration case. For example, you can manually assign the short address fc80::1 instead of the long fc80:0:0:0:0200::1.

• Question 212:

  Which of the following settings could prevent two potential EIGRP neighbors from becoming neighbors? (Choose two answers.)

  A. The interface used by one router to connect to the other router is passive in the EIGRP process.
  B. Duplicate EIGRP router IDs
  C. Mismatched Hold Timers.
  D. IP addresses of 10.1.1.1/24 and 10.2.2.2/24, respectively.
  A. The interface used by one router to connect to the other router is passive in the EIGRP process.
  D. IP addresses of 10.1.1.1/24 and 10.2.2.2/24, respectively.

  ---

  Reference: http://smitley.net/?p=167 (see `configuration settings that could prevent neighbor relationships')

• Question 213:

  Which statement is correct based upon the following output from the show command on RT1?

  

  Choose one from below:

  A. OSPFv3 establishes neighbor adjacencies by using Link-local addresses.
  B. OSPFv3 establishes neighbor adjacencies by using IPv4 addresses.
  C. OSPFv3 establishes neighbor adjacencies by using global IPv6 addresses.
  D. RT1 owns a subnet mask of 64 bits.
  A. OSPFv3 establishes neighbor adjacencies by using Link-local addresses.

  ---

  The point of this question is the OSPFv3.

  As shown information, we notice that the router with both ipv6 address and ipv4 address and both of them are in ospf prosess, so in OSPFv3, we can find that, the DR BDR address are all link local address, so in OSPFv3 it establist neighbor

  with link local address.

• Question 214:

  Refer to the exhibit diagram and configuration. RTB is summarizing its networks from AS 64100 with the aggregate-address command. However, the show ip route command on RTA reveals the RTB individual networks as well as its summary route. Which option would ensure that only the summary route would appear in the routing table of RTA?

  

  A. Delete the four network statements and leave only the aggregate-address statement in the BGP configuration.
  B. Add the keyword summary-only to the aggregate-address command.
  C. Add a static route with a prefix of 192.168.24.0 255.255.252.0 pointing to the null0 interface.
  D. Create a route map permitting only the summary address.
  B. Add the keyword summary-only to the aggregate-address command.

  ---

  When the aggregate-address command is used within BGP routing, the aggregated address is advertised, along with the more specific routes. The exception to this rule is through the use of the summary-only command. The "summary-only" keyword suppresses the more specific routes and announces only the summarized route.

• Question 215:

  Which of the below mentioned conditions form a neighbor relationship in EIGRP? (Choose three)

  A. Hello or ACK received
  B. AS number match
  C. Hello timer match
  D. Identical metric (k values)
  E. Dead Timer Match
  A. Hello or ACK received
  B. AS number match
  D. Identical metric (k values)

• Question 216:

  Which two statements are true about using IPv4 and IPv6 simultaneously on a network segment? (Choose two.)

  A. Hosts can be configured to receive both IPv4 and IPv6 addresses via DHCP.
  B. Host configuration options for IPv4 can be either statically assigned or assigned via DHCP. Host configuration options for IPv6 can be statically assigned only.
  C. IPv6 allows a host to create its own IPv6 address that will allow it to communicate to other devices on a network configured via DHCP. IPv4 does not provide a similar capability for hosts.
  D. IPv4 and IPv6 addresses can be simultaneously assigned to a host but not to a router interface.
  E. IPv6 provides for more host IP addresses but IPv4 provides for more network addresses.
  A. Hosts can be configured to receive both IPv4 and IPv6 addresses via DHCP.
  C. IPv6 allows a host to create its own IPv6 address that will allow it to communicate to other devices on a network configured via DHCP. IPv4 does not provide a similar capability for hosts.

  ---

  Like DHCP in IPv4, IPv6 hosts can also be configured to acquire connectivity parameters from DHCPv6 servers. IPv4 clients use DHCP broadcasts to locate DHCP servers, and since broadcasts are extinct in IPv6, clients use specialized multicasts to locate DHCPv6 servers. These multicasts use the reserved address FF02::1:2. One notable difference between DHCP and DHCPv6 is that while DHCP can inform clients which node to use as the default gateway, DHCPv6 does not do this.

• Question 217:

  Refer to the exhibit.

  

  In a redundant hub-and-spoke deployment using EIGRP, what feature can be used to ensure that routers C through F are not used as transit routers for data traveling from router B to network 10.1.1.0? Select the best response

  A. Use address summarization at routers C, D, E, and F.
  B. Use the EIGRP Stub feature on routers C, D, E, and F.
  C. Use passive-interface on the spoke links in routers A and B.
  D. Change the administrative distance in routers A and B for routes learned from routers C, D, E, and F.
  B. Use the EIGRP Stub feature on routers C, D, E, and F.

  ---

  By configuring "stub" feature on routers C D E and F, routers A and B will not try to transit traffic through these routers. For example, if the network connecting from routers A and B is down, router B will not send to network 10.1.1.0/24 from router B -> routerC/D/E/F -> router A -> network 10.1.1.0/24.

• Question 218:

  Exhibit:

  

  Refer to the topology diagram R3 is redistributing the EIGRP routers into OSPF. What will the EIGRP routes appear in the routing table of R1?

  A. O
  B. O IA
  C. E2
  D. D
  E. D EX
  C. E2

  ---

  Reference: http://kowon.dongseo.ac.kr/ nok60/lecture/CCNP1-V50/Labs/CCNP1v50_L5- 2.pdf (page 10 and 11) ~

• Question 219:

  Refer to the exhibit.

  

  Which one statement is true?

  A. Traffic from the 172.16.0.0/16 network will be blocked by the ACL.
  B. The 10.0.0.0/8 network will not be advertised by Router B because the network statement for the 10.0.0.0/8 network is missing from Router B.
  C. The 10.0.0.0/8 network will not be in the routing table on Router B.
  D. Users on the 10.0.0.0/8 network can successfully ping users on the 192.168.5.0/24 network, but users on the 192.168.5.0/24 cannot successfully ping users on the 10.0.0.0/8 network.
  E. Router B will not advertise the 10.0.0.0/8 network because it is blocked by the ACL.
  E. Router B will not advertise the 10.0.0.0/8 network because it is blocked by the ACL.

  ---

  In this example, access-list 7 is used to specify which networks will be advertised out the interface on the distribute list. Ths ACL only allows for the 172.16.0.0/16 to be advertised out, so 10/0/0;0/8 will indeed be filtered and will not be advertised to any upstream routers.

• Question 220:

  Refer to the exhibit.

  

  Routers R1 and R2 have established a neighbor relationship and are exchanging routing information. The network design requires that R1 receive routing updates from R2, but not advertise any routes to R2. Which configuration command sequence will successfully accomplish this task?

  A. R1(config)# router eigrp 1 R1(config-router)# passive-interface serial 0
  B. R2(config)# router eigrp 1 R2(config-router)# passive-interface serial 0
  C. R1(config)# access-list 20 deny any R1(config)# router eigrp 1 R1(config-router)# distribute-list 20 out serial 0
  D. R2(config)# access-list 20 deny any R2(config)# router eigrp 1 R2(config-router)# distribute-list 20 out serial 0
  E. R1(config)# access-list 20 permit any R1(config)# router eigrp 1 R1(config-router)# distribute-list 20 in serial 0
  F. R2(config)# access-list 20 permit any R2(config)# router eigrp 1 R2(config-router)# distribute-list 20 in serial 0
  C. R1(config)# access-list 20 deny any R1(config)# router eigrp 1 R1(config-router)# distribute-list 20 out serial 0

  ---

  We can not use passive-interfaces to accomplish this task because the "passive-interface..." command (in EIGRP or OSPF) will shut down the neighbor relationship of these two routers (no hello packets are exchanged). And to filter routing updates we should configure a distribute list on R1 with an access list that deny all and apply it to the outbound direction so that R1 can receive but cannot send routing updates.