CCNA Interview Question -3

41 You are given the following address: 153.50.6.27/25. Determine the subnet mask, address class, subnet address, and broadcast address.
A. 255.255.255.128, B,153.50.6.0, 153.50.6.127
B. 255.255.255.128, C,153.50.6.0, 153.50.6.127
C. 255.255.255.128, C,153.50.6.127, 153.50.6.0
D. 255.255.255.224, C,153.50.6.0, 153.50.6.127
Ans A

42 You are given the following address: 128.16.32.13/30. Determine the subnet mask, address class, subnet address,
and broadcast address.
A. 255.255.255.252, B,128.16.32.12, 128.16.32.15
B. 255.255.255.252, C,128.16.32.12, 128.16.32.15
C. 255.255.255.252, B,128.16.32.15, 128.16.32.12
D. 255.255.255.248, B,128.16.32.12, 128.16.32.15
Ans A
 

43 You are given the following address: 15.16.193.6/21. Determine the subnet mask, address class, subnet address,
and broadcast address.
A. 255.255.248.0, A, 15.16.192.0, 15.16.199.255
B. 255.255.248.0, B, 15.16.192.0, 15.16.199.255
C. 255.255.248.0, A, 15.16.199.255, 14.15.192.0
D. 255.255.242.0, A, 15.16.192.0, 15.16.199.255
Ans A

44 You have an IP host address of 201.222.5.121 and a subnet mask of 255.255.255.248. What is the broadcast address?
A. 201.222.5.127
B. 201.222.5.120
C. 201.222.5.121
D. 201.222.5.122

Ans A
The easiest way to calculate this is to subtract 255.255.255.248 (subnet mask) from 255.255.255.255, this
equals 7. Convert the address 201.222.5.121 to binary--11001001 11011110 00000101 01111001. Convert the
mask 255.255.255.248 to binary--11111111 11111111 11111111 11111000. AND them together to get: 11001001 11011110
00000101 01111000 or 201.222.5.120. 201.222.5.120 is the subnet address, add 7 to this address for 201.222.5.127 or
the broadcast address. 201.222.5.121 through 201.222.5.126 are the valid host addresses.

45 Given the address 172.16.2.120 and the subnet mask of 255.255.255.0. How many hosts are available?
A. 254
B. 510
C. 126
D. 16,372

Ans A
172.16.2 120 is a standard Class B address with a subnet mask that allows 254 hosts. 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. The subnet mask is 255.255.255.248.

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.

51 Which addresses are INCORRECTLY paired with their class?
A. 240 - 255, Class D
B. 240 - 255, Class E
C. 224 - 239, Class D
D. 224 - 239, Class E

Ans A & D
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.

52 Which IP Address Class is INCORRECTLY paired with its range of network numbers?
A. Class A addresses include 192.0.0.0 through 223.255.255.0
B. Class A addresses include 1.0.0.0 through 126.0.0.0
C. Class B addresses include 128.0.0.0 through 191.255.0.0
D. Class C addresses include 192.0.0.0 through 223.255.255.0
E. Class D addresses include 224.0.0.0 through 239.255.255.0

Ans A
Class A addresses include 1.0.0.0 through 126.0.0.0
Class B addresses include 128.0.0.0 through 191.255.0.0
Class C addresses include 192.0.0.0 through 223.255.255.0
Class D addresses include 224.0.0.0 through 239.255.255.0

53 Which IP Address Class can have 16 million subnets but support 254 hosts?
A. Class C
B. Class A
C. Class B
D. Class D

Ans A
Possible Subnets IP Address Class Possible Hosts
254 A 16M.
64K B 64K
16M C 254

54 Which IP Address Class can have 64,000 subnets with 64,000 hosts per subnet?
A. Class B
B. Class A
C. Class C
D. Class D

Ans A
IP Address Class Possible Subnets Possible Hosts
254 A 16M
64K B 64K
16M C 254

55 There are two processes to pair MAC address with IP addresses. Which process finds an IP address from a MAC address?
A. RARP
B. ARP
C. RIP
D. IGRP

Ans A
ARP (Address Resolution Protocol) maps an IP address to the MAC address, RARP (Reverse Address Resolution Protocol) maps the MAC address to the IP address. ARP and RARP work at the internet layer of the Internet Model or the network layer of the OSI model.

56 When the router runs out of buffer space, this is called ________.
A. Source Quench
B. Redirect
C. Information Request
D. Low Memory

Ans A
Source quench is the process where the destination router, or end internetworking device will "quench" the date from the "source", or the source router. This usually happens when the destination router runs out of buffer space to process packets.

57 Which protocol carries messages such as destination Unreachable, Time Exceeded, Parameter Problem, Source Quench, Redirect, Echo, Echo Reply, Timestamp, Information Request, Information Reply, Address Request, and Address Reply?
A. ICMP
B. UDP
C. TCP
D. TFTP
E. FTP

Ans A
ICMP (Internet Control Message Protocol) is a network layer internet protocol described in RFC # 792. ICMP reports IP packet information such as destination Unreachable, Time Exceeded, Parameter Problem, Source Quench, Redirect, Echo, Echo Reply, Timestamp, Information Request, Information Reply, Address Request, and Address Reply.

58 Two of the protocols that can be carried in the Protocol field of an IP packet are?
A. TCP
B. UDP
C. FTP
D. TFTP

Ans A & B
The following are the fields in an IP segment,their length, and their definitions:
VERS (Version number - 16 bits)
HLEN (Number of 32-bit words in the header - 4 bits)
Type of Server (How the datagram should be handled - 32 bits)
Total Length (Total length of header and data - 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet - 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet - 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet - 6 bits)
TTL (Time-To-Live - 6 bits)
Protocol (Upperlayer protocol sending the datagram - 16 bits)
Header Checksum )Integrity check on the header - 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others - 4 bits)
Data (4 bits).

59 Where would network testing be included in an IP packet?
A. IP Options field
B. Identification field
C. Type of Service field
D. Reservation field

Ans A
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number - 16 bits)
HLEN (Number of 32-bit words in the header - 4 bits)
Type of Server (How the datagram should be handled - 32 bits)
Total Length (Total length of header and data - 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet - 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet - 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet - 6 bits)
TTL (Time-To-Live - 6 bits)
Protocol (Upperlayer protocol sending the datagram - 16 bits)
Header Checksum )Integrity check on the header - 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others - 4 bits)
Data (4 bits).

60 What field tells the Internet layer how to handle an IP packet?
A. Type of Service
B. Identification
C. Flags
D. Frag Offset

Ans A
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number - 16 bits)
HLEN (Number of 32-bit words in the header - 4 bits)
Type of Server (How the datagram should be handled - 32 bits)
Total Length (Total length of header and data - 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet - 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet - 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet - 6 bits)
TTL (Time-To-Live - 6 bits)
Protocol (Upperlayer protocol sending the datagram - 16 bits)
Header Checksum )Integrity check on the header - 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others - 4 bits) Data (4 bits).