ccna interview questions and answers

Part - 15 CCNA Interview Questions and Answers

71 Cisco routers use wildcard masking to identify how to check or ignore corresponding
IP address bits. What does setting a wildcard mask bit to 0 cause the router to do?

A. It tells the router to check the corresponding bit value.

B. It tells the router to ignore the corresponding bit value.

C. It tells the router to check its alternate routing list.

D. It tells the router to use its primary routing list.

Ans A

It tells the router to check the corresponding bit value.

72 You are a system administrator and you want to deny access to a group of computers with addresses 172.30.16.0 to 172.30.31.0. Which wildcard mask would you use?

A. 0.0.15.255

B. 0.0.255.255

C. 0.0.31.255

D. 0.0.127.255

E. 0.0.255.255

Ans: A

0.0.15.255 will check the last 13 bits of an address so that computers 172.30.16.0 to 172.30.31.0 will be denied access. 0.0.31.255 would check the last 6 binary digits and deny access to addresses 172.30.32.0 to 172.30.63.0. 0.0.127.255 would check the last 7 binary digits and deny access to addresses 172.30.64.0 to 172.30.127.0. 0.0.255.255 would deny 172.30.0.0 to 172.30.254.0. If you write decimal 15 in binary, you have 0001111, the 1's tell the router to ignore address with these bits set; 0's tell the router to check the bits. The third octet for 172.30.16.0 is 00010000. The third octet for 172.30.31.0 would be 00011111. So, traffic from these addresses would be denied.

73 In order to limit the quantity of numbers that a system administrator has to enter, Cisco can use which abbreviation to indicate 0.0.0.0?

A. host

B. any

C. all

D. include

Ans: A

Cisco uses host to specify 0.0.0.0. This tells the router to check all. Cisco uses any to specify 255.255.255.255. This tells the router to ignore all and permit any address to use an access list test.

74 What do the following commands accomplish? access-list 1 permit 172.16.0.0 0.0.255.255 interface ethernet 0 IP access-group 1 out interface ethernet 1 IP access-group 1 out

A. Only traffic from the source network 172.16.0.0 will be blocked.

B. Only traffic from the source network 172.16.0.0 will be forwarded. Non-172.16.0.0 network traffic is blocked.

C. Non-172.16.0.0 traffic will be forwarded.

D. All traffic will be forwarded.

Ans: B

Only traffic from the source network 172.16.0.0 will be forwarded. Non-172.16.0.0 network traffic is blocked. The wildcard mask 0.0.255.255 tells the router to check the first 2 octets and to ignore the last 2 octets.

75 When using access lists, it is important where those access lists are placed. Which statement best describes access list placement?

A. Put standard access lists as near the destination as possible. Put extended access lists as close to the source as possible.

B. Put extended access lists as near the destination as possible. Put standard access lists as close to the source as possible.

C. It isn't import where access lists are placed since the router will read and cache the whole list.

D. Put access lists as close to corporate headquarters as possible.

Ans A

Put standard access lists as near the destination as possible. Put extended access lists as close to the source as possible. Standard access lists don't specify the destination address.