ccna interview questions and answers

Part - 10 CCNA Interview Questions and Answers

46 Which addresses are valid host addresses?

A. 201.222.5.17

B. 201.222.5.18

C. 201.222.5.16

D. 201.222.5.19

E. 201.222.5.31

Ans A,B & D

Subnet addresses in this situation are all in multiples of 8. In this example, 201.222.5.16 is the subnet, 201.22.5.31 is the broadcast address. The rest are valid host IDs on subnet 201.222.5.16.

47 You are a network administrator and have been assigned the IP address of 201.222.5.0. You need to have 20 subnets with 5 hosts per subnet. What subnet mask will you use?

A. 255.255.255.248

B. 255.255.255.128

C. 255.255.255.192

D. 255.255.255.240

Ans A

By borrowing 5 bits from the last octet, you can. have 30 subnets. If you borrowed only 4 bits you could only have 14 subnets. The formula is (2 to the power of n)-2. By borrowing 4 bits, you have (2x2x2x2)-2=14. By borrowing 5 bits, you have (2x2x2x2x2)-2=30. To get 20 subnets, you would need to borrow 5 bits so the subnet mask would be 255.255.255.248.

48 You are given the IP address of 172.16.2.160 with a subnet mask of 255.255.0.0. What is
the network address in binary?

A. 10101100 00010000

B. 00000010 10100000

C. 10101100 00000000

D. 11100000 11110000

Ans: A

To find the network address, convert the IP address to binary--10101100 000100000 00000010 10100000--then ANDed it with the subnet mask--11111111 11111111 00000000 00000000. The rest is 10101100 00010000 00000000 00000000, which is 172.16.0.0 in decimal. The first octet rule states that the class of an address can be determined by the numerical value of the first octet.

49 Which addresses are INCORRECTLY paired with their class?

A. 128 to 191, Class B

B. 192 to 223 Class B

C. 128 to 191, Class C

D. 192 to 223, Class C

Ans B & C

Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and 240 to 255, Class E. The first octet rule states that the class of an address can be determined by the numerical value of the first octet.

50 Which addresses are INCORRECTLY paired with their class?

A. 1 to 126, Class A

B. 128 to 191, Class A

C. 1 to 126, Class B

D. 128 to 191, Class B

Ans:B & C.

Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and 240 to 255, Class E. The first octet rule states that the class of an address can be determined by the numerical value of the first octet