computer network question bank

8/12/2019 computer network question bank

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1. Which of the following services use TCP?

DHCP

SMTP

HTTP

TFTP

FTP

A. 1 and 2

B. 2, 3 and 5

C. 1, 2 and 4

D. 1, 3 and 4

Answer:Option B

Explanation: SMTP, HTTP and FTP use TCP.

2.

What layer in the TCP/IP stack is equivalent to the Transport layer of the OSI model?

A. Application

B. Host-to-Host

C. Internet

D. Network Access

Answer:Option B

Explanation:

The four layers of the TCP/IP stack (also called the DoD model) are Application/Process, Host-

to-Host, Internet, and Network Access. The Host-to-Host layer is equivalent to the Transport

layer of the OSI model.

3.

Which of the following describe the DHCP Discover message?

1. It uses FF:FF:FF:FF:FF:FFas a layer 2 broadcast.


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2. It uses UDP as the Transport layer protocol.

3. It uses TCP as the Transport layer protocol.

4.

It does not use a layer 2 destination address.

A. 1 only

B. 1 and 2

C. 3 and 4

D. 4 only

Answer:Option B

Explanation:

A client that sends out a DHCP Discover message in order to receive an IP address sends out a

broadcast at both layer 2 and layer 3. The layer 2 broadcast is all Fs in hex, or FF:FF:FF:FF:FF:FF.

The layer 3 broadcast is 255.255.255.255, which means all networks and all hosts. DHCP isconnectionless, which means it uses User Datagram Protocol (UDP) at the Transport layer, also called

the Host-to-Host layer.

4. You want to implement a mechanism that automates the IP configuration, including IP address,

subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this?

A. SMTP B. SNMP

C. DHCP D. ARP

Answer:Option CExplanation:

Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts on your

network. DHCP can provide a lot of information, but the most common is IP address, subnet mask,

default gateway, and DNS information.

5. Which of the following is private IP address?

A. 12.0.0.1 B. 168.172.19.39

C. 172.15.14.36 D. 192.168.24.43

Answer:Option D

Explanation:

Class A private address range is 10.0.0.0 through 10.255.255.255. Class B private address range is

172.16.0.0 through 172.31.255.255, and Class C private address range is 192.168.0.0 through

192.168.255.255.

6. Which of the following allows a router to respond to an ARP request that is intended for a remote


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host?

A. Gateway DP

B. Reverse ARP (RARP)

C. Proxy ARP

D. Inverse ARP (IARP)

Answer:Option C

Explanation:

Proxy ARP can help machines on a subnet reach remote subnets without configuring routing or a

default gateway.

7. If you use either Telnet or FTP, which is the highest layer you are using to transmit data?

A. Application B. Presentation

C. Session D. Transport

Answer:Option A

Explanation:

Both FTP and Telnet use TCP at the Transport layer; however, they both are Application layer

protocols, so the Application layer is the best answer.

8.

Which class of IP address provides a maximum of only 254 host addresses per network ID?

A. Class A

B. Class B

C. Class C

D. Class D

Answer:Option C

Explanation:

A Class C network address has only 8 bits for defining hosts: 28- 2 = 254.

9. Which statements are true regarding ICMP packets?

1.

They acknowledge receipt of a TCP segment.

2. They guarantee datagram delivery.

3. They can provide hosts with information about network problems.


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4. They are encapsulated within IP datagrams.

A. 1 only

B. 2 and 3

C. 3 and 4

D. 2, 3 and 4

Answer:Option C

Explanation:

Internet Control Message Protocol (ICMP) is used to send error messages through the network, but

they do not work alone. Every segment or ICMP payload must be encapsulated within an IP datagram

(or packet).

10. Which layer 4 protocol is used for a Telnet connection?

A. IP B. TCP

C. TCP/IP D. UDP

Answer:Option B

Explanation:

Although Telnet does use TCP and IP (TCP/IP), the question specifically asks about layer 4, and IP

works at layer 3. Telnet uses TCP at layer 4.

11. Which statements are true regarding ICMP packets?

1. ICMP guarantees datagram delivery.

2.

ICMP can provide hosts with information about network problems.

3. ICMP is encapsulated within IP datagrams.

4. ICMP is encapsulated within UDP datagrams.

A. 1 only

B. 2 and 3

C. 1 and 4

D. All of the above


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Answer:Option B

Explanation:

ICMP is used for diagnostics and destination unreachable messages. ICMP is encapsulated within IP

datagrams, and because it is used for diagnostics, it will provide hosts with information about network

problems.

12. What protocol is used to find the hardware address of a local device?

A. RARP B. ARP

C. IP D. ICMP

Answer:Option B

Explanation:

Address Resolution Protocol (ARP) is used to find the hardware address from a known IP address.

13. Which of the following protocols uses both TCP and UDP?

A. FTP B. SMTP

C. Telnet D. DNS

Answer:Option D

Explanation:

DNS uses TCP for zone exchanges between servers and UDP when a client is trying to resolve a

hostname to an IP address.

14. What is the address range of a Class B network address in binary?

A. 01xxxxxx

B. 0xxxxxxx

C. 10xxxxxx

D. 110xxxxx

Answer:Option CExplanation:

The range of a Class B network address is 128-191. This makes our binary range10xxxxxx.

15. Which of the following is the decimal and hexadecimal equivalents of the binary number

10011101?

A. 155, 0x9B


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B. 157, 0x9D

C. 159, 0x9F

D. 185, 0xB9

Answer:Option B

Explanation:

To turn a binary number into decimal, you just have to add the values of each bit that is a 1. The

values of 10011101 are 128, 16, 8, 4, and 1. 128 + 16 + 8 + 4 + 1 = 157.

Hexadecimal is a base-16 number system. The values of hexadecimal are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,

A, B, C, D, E, F-16 characters total, from which to create all the numbers you'll ever need. So, if 1001

in binary is 9, then the hexadecimal equivalent is 9. Since we then have 1101, which is 13 in binary,

the hexadecimal answer is D and the complete hexadecimal answer is 0x9D.

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