Computer Network MCQ Objective Questions

Multiple Choice Questions of Computer Networking

(Ans In Red Colour)

1-1 Computer Network is
A.  Collection of hardware components and computers
B.  Interconnected by communication channels
C.  Sharing of resources and information
D.  All of the Above

1-2 What is a Firewall in Computer Network?
A.  The physical boundary of Network
B.  An operating System of Computer Network    
C.  A system designed to prevent unauthorized access
D.  A web browsing Software

1-3 How many layers does OSI Reference Model has?
A.  4
B.  5
C.  6
D.  7

1-4 DHCP is the abbreviation of
A.  Dynamic Host Control Protocol
B.  Dynamic Host Configuration Protocol
C.  Dynamic Hyper Control Protocol
D.  Dynamic Hyper Configuration Protocol

1-5 IPV4 Address is
A.  8 bit
B.  16 bit
C.  32 bit
D.  64 bit

1-6 DNS is the abbreviation of
A.  Dynamic Name System
B.  Dynamic Network System
C.  Domain Name System
D.  Domain Network Service

1-7 What is the meaning of Bandwidth in Network?
A.  Transmission capacity of a communication channels
B.  Connected Computers in the Network
C.  Class of IP used in Network
D.  None of Above

1-8 ADSL is the abbreviation of
A.  Asymmetric Dual Subscriber Line
B.  Asymmetric Digital System Line
C.  Asymmetric Dual System Line
D.  Asymmetric Digital Subscriber Line

1-9 What is the use of Bridge in Network?
A.  to connect LANs
B.  to separate LANs
C.  to control Network Speed
D.  All of the above

1-10 Router operates in which layer of OSI Reference Model?
A.  Layer 1 (Physical Layer)
B.  Layer 3 (Network Layer)
C.  Layer 4 (Transport Layer)
D.  Layer 7 (Application Layer)

Answers

1 – D / 2 – C / 3 – D / 4 – B / 5 – C / 6 – C / 7 – A / 8 – D / 9 – A / 10 – B

 2-1 Each IP packet must contain
A. Only Source address
B. Only Destination address
C. Source and Destination address
D. Source or Destination address

2-2 Bridge works in which layer of the OSI model?
A. Appliation layer
B. Transport layer                
C. Network layer
D. Datalink layer

2-3 _______ provides a connection-oriented reliable service for sending messages
A. TCP
B. IP
C. UDP
D. All of the above

2-4 Which layers of the OSI model are host-to-host layers?
A. Transport, Session, Persentation, Application
B. Network, Transport, Session, Presentation
C. Datalink, Network, Transport, Session
D. Physical, Datalink, Network, Transport

2-5 Which of the following IP address class is Multicast
A. Class A
B. Class B
C. Class C
D. Class D

2-6 Which of the following is correct regarding Class B Address of IP address
A. Network bit – 14, Host bit – 16
B. Network bit – 16, Host bit – 14
C. Network bit – 18, Host bit – 16
D. Network bit – 12, Host bit – 14

2-7 The last address of IP address represents
A. Unicast address
B. Network address
C. Broadcast address
D. None of above

2-8 How many bits are there in the Ethernet address?
A. 64 bits
B. 48 bits
C. 32 bits
D. 16 bits

2-9 How many layers are in the TCP/IP model?
A. 4 layers
B. 5 layers
C. 6 layers
D. 7 layers

2-10 Which of the following layer of OSI model also called end-to-end layer?
A. Presentation layer
B. Network layer
C. Session layer
D. Transport layer

 Answers

1 – C / 2 – D / 3 – A / 4 – A / 5 – D / 6 – A / 7 – C / 8 – B / 9 – A / 10 – D

3-1. Why IP Protocol is considered as unreliable?
A. A packet may be lost
B. Packets may arrive out of order
C. Duplicate packets may be generated
D. All of the above

3-2. What is the minimum header size of an IP packet?
A. 16 bytes
B. 10 bytes          
C. 20 bytes
D. 32 bytes

3-3. Which of following provides reliable communication?
A. TCP
B. IP
C. UDP
D. All of the above

3-4. What is the address size of IPv6 ?
A. 32 bit
B. 64 bit
C. 128 bit
D. 256 bit

3-5. What is the size of Network bits & Host bits of Class A of IP address?
A. Network bits 7, Host bits 24
B. Network bits 8, Host bits 24
C. Network bits 7, Host bits 23
D. Network bits 8, Host bits 23

3-6. What does Router do in a network?
A. Forwards a packet to all outgoing links
B. Forwards a packet to the next free outgoing link
C. Determines on which outing link a packet is to be forwarded
D. Forwards a packet to all outgoing links except the originated link

3-7. The Internet is an example of
A. Cell switched network
B. circuit switched network
C. Packet switched network
D. All of above

3-8. What does protocol defines? 
A. Protocol defines what data is communicated.
B. Protocol defines how data is communicated.
C. Protocol defines when data is communicated.
D. All of above

3-9. What is the uses of subnetting?
A. It divides one large network into several smaller ones
B. It divides network into network classes
C. It speeds up the speed of network
D. None of above

3-10. Repeater operates in which layer of the OSI model?
A. Physical layer
B. Data link layer
C. Network layer
D. Transport layer

 Answers

1 – D / 2 – C / 3 – A / 4 – C / 5 – A / 6 – C / 7 – C / 8 – D / 9 – A / 10 – A

4-1. What is the benefit of the Networking?
A. File Sharing
B. Easier access to Resources
C. Easier Backups
D. All of the Above

4-2. Which of the following is not the Networking Devices?
A. Gateways
B. Linux          
C. Routers
D. Firewalls

4-3. What is the size of MAC Address?
A. 16-bits
B. 32-bits
C. 48-bits
D. 64-bits

4-4. Which of the following can be Software?
A. Routers
B. Firewalls
C. Gateway
D. Modems

4-5. What is the use of Ping command?
A. To test a device on the network is reachable
B. To test a hard disk fault
C. To test a bug in a Application
D. To test a Pinter Quality

4-6. MAC Address is the example of
A. Transport Layer
B. Data Link Layer
C. Application Layer
D. Physical Layer

4-7. Routing tables of a router keeps track of
A. MAC Address Assignments
B. Port Assignments to network devices
C. Distribute IP address to network devices
D. Routes to use for forwarding data to its destination

4-8. Layer-2 Switch is also called
A. Multiport Hub
B. Multiport Switch
C. Multiport Bridge
D. Multiport NIC

4-9. Difference between T568A and T568B is
A. Difference in wire color
B. Difference in number of wires
C. Just different length of wires
D. Just different manufacturer standards

4-10. The meaning of Straight-through Cable is
A. Four wire pairs connect to the same pin on each end
B. The cable Which Directly connects Computer to Computer
C. Four wire pairs not twisted with each other
D. The cable which is not twisted

 Answers

1 – D / 2 – B / 3 – C / 4 – B / 5 – A / 6 – B / 7 – D / 8 – C / 9 – D / 10 – A

5-1 Which of the following is not the External Security Threats?
A. Front-door Threats
B. Back-door Threats
C. Underground Threats
D. Denial of Service (DoS)

5-2 What is the Demilitarized Zone?
A. The area between firewall & connection to an external network
B. The area between ISP to Military area          
C. The area surrounded by secured servers
D. The area surrounded by the Military

5-3 What is the full form of RAID ?
A. Redundant Array of Independent Disks
B. Redundant Array of Important Disks
C. Random Access of Independent Disks
D. Random Access of Important Disks

5-4 What is the maximum header size of an IP packet?
A. 32 bytes
B. 64 bytes
C. 30 bytes
D. 60 bytes

5-5 What is the size of Host bits in Class B of IP address?
A. 04
B. 08
C. 16
D. 32

5-6 What is the usable size of Network bits in Class B of IP address?
A. 04
B. 08
C. 14
D. 16

5-7 In which type of RAID, data is mirrored between two disks.
A. RAID 0
B. RAID 1
C. RAID 2
D. RAID 3

5-8 What do you mean by broadcasting in Networking?
A. It means addressing a packet to all machine
B. It means addressing a packet to some machine
C. It means addressing a packet to a particular machine
D. It means addressing a packet to except a particular machine

5-9 Which of the following is/are Protocols of Application?
A. FTP
B. DNS
C. Telnet
D. All of above

5-10 Which of the following protocol is/are defined in Transport layer?
A. FTP
B. TCP
C. UDP
D. B & C

 Answers

1 – C / 2 – A / 3 – A / 4 – D / 5 – C / 6 – C / 7 – B / 8 – A / 9 – D / 10 – D

 Networking Basics - Networking Basics

·         Networking Basics - Networking Basics

1.	How long is an IPv6 address?
	A. 32 bits B. 128 bytes C. 64 bits D. 128 bits Answer: Option D Explanation: An IPv6 address is 128 bits long.

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2.	What flavor of Network Address Translation can be used to have one IP address allow many users to connect to the global Internet?
	A. NAT B. Static C. Dynamic D. PAT Answer: Option D Explanation: Port Address Translation (PAT) allows a one-to-many approach to network address translation.

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3.	What are the two main types of access control lists (ACLs)? 1.    Standard 2.    IEEE 3.    Extended 4.    Specialized
	A. 1 and 3 B. 2 and 4 C. 3 and 4 D. 1 and 2 Answer: Option A Explanation: Standard and extended access control lists (ACLs) are used to configure security on a router.

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4.	What command is used to create a backup configuration?
	A. copy running backup B. Copy running-config startup-config C. config mem D. wr mem Answer: Option B Explanation: The command to back up the configuration on a router is copy running-config startup-config.

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5.	You have 10 users plugged into a hub running 10Mbps half-duplex. There is a server connected to the switch running 10Mbps half-duplex as well. How much bandwidth does each host have to the server?
	A. 100 kbps B. 1 Mbps C. 2 Mbps D. 10 Mbps Answer: Option D Explanation: Each device has 10 Mbps to the server.

6.	Which WLAN IEEE specification allows up to 54Mbps at 2.4GHz?
	A. A B. B C. G D. N Answer: Option C Explanation: IEEE 802.11B is 2.4GHz, but with a maximum of only 11Mbps. IEEE 802.11G is in the 2.4GHz range, with a top speed of 54Mbps.

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7.	Which of the following is the valid host range for the subnet on which the IP address 192.168.168.188 255.255.255.192 resides?
	A. 192.168.168.129-190 B. 192.168.168.129-191 C. 192.168.168.128-190 D. 192.168.168.128-192 Answer: Option A Explanation: 256 - 192 = 64. 64 + 64 = 128. 128 + 64 = 192. The subnet is 128, the broadcast address is 191, and the valid host range is the numbers in between, or 129-190.

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8.	To back up an IOS, what command will you use?
	A. backup IOS disk B. copy ios tftp C. copy tftp flash D. copy flash tftp Answer: Option D Explanation: The command copy flash tftp will prompt you to back up an existing IOS in flash to a TFTP host.

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9.	What protocol does PPP use to identify the Network layer protocol?
	A. NCP B. ISDN C. HDLC D. LCP Answer: Option A Explanation: Network Control Protocol is used to help identify the Network layer protocol used in the packet.

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10.	Which of the following commands will allow you to set your Telnet password on a Cisco router?
	A. line telnet 0 4 B. line aux 0 4 C. line vty 0 4 D. line con 0 Answer: Option C Explanation: The command line vty 0 4 places you in a prompt that will allow you to set or change your Telnet password

11.	Which protocol does DHCP use at the Transport layer?
	A. IP B. TCP C. UDP D. ARP Answer: Option C Explanation: User Datagram Protocol is a connection network service at the Transport layer, and DHCP uses this connectionless service.

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12.	Which command is used to determine if an IP access list is enabled on a particular interface?
	A. show access-lists B. show interface C. show ip interface D. show interface access-lists Answer: Option C Explanation: The show ip interface command will show you if any outbound or inbound interfaces have an access list set.

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13.	Where is a hub specified in the OSI model?
	A. Session layer B. Physical layer C. Data Link layer D. Application layer Answer: Option B Explanation: Hubs regenerate electrical signals, which are specified at the Physical layer.

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14.

What does the passive command provide to dynamic routing protocols?

A. Stops an interface from sending or receiving periodic dynamic updates. B. Stops an interface from sending periodic dynamic updates but not from receiving updates. C. Stops the router from receiving any dynamic updates. D. Stops the router from sending any dynamic updates. Answer: Option B Explanation: The passive command, short for passive-interface, stops regular updates from being sent out an interface. However, the interface can still receive updates.

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15.	Which protocol is used to send a destination network unknown message back to originating hosts?
	A. TCP B. ARP C. ICMP D. BootP Answer: Option C Explanation: ICMP is the protocol at the Network layer that is used to send messages back to an originating router. 16.  How often are BPDUs sent from a layer 2 device? A. Never B. Every 2 seconds C. Every 10 minutes D. Every 30 seconds Answer: Option B Explanation: Every 2 seconds, BPDUs are sent out from all active bridge ports by default. 17.  How many broadcast domains are created when you segment a network with a 12-port switch? A. 1 B. 2 C. 5 D. 12 Answer: Option A Explanation: By default, switches break up collision domains but are one large broadcast domain. 18.  What does the command routerA(config)#line cons 0 allow you to perform next? A. Set the Telnet password. B. Shut down the router. C. Set your console password. D. Disable console connections. Answer: Option C Explanation: The command line console 0 places you at a prompt where you can then set your console user-mode password. 19.  Which router command allows you to view the entire contents of all access lists? A. show all access-lists B. show access-lists C. show ip interface D. show interface Answer: Option B Explanation: To see the contents of all access lists, use the show access-lists command. 20.  Which class of IP address has the most host addresses available by default? A. A B. B C. C D. A and B Answer: Option A Explanation: Class A addressing provides 24 bits for host addressing.
21.	In a network with dozens of switches, how many root bridges would you have?
	A. 1 B. 2 C. 5 D. 12 Answer: Option A Explanation: You should have only one root bridge per network.

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22.	What PPP protocol provides dynamic addressing, authentication, and multilink?
	A. NCP B. HDLC C. LCP D. X.25 Answer: Option C Explanation: Link Control Protocol in the PPP stack provides dynamic addressing, authentication, and multilink.

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23.	What is a stub network?
	A. A network with more than one exit point. B. A network with more than one exit and entry point. C. A network with only one entry and no exit point. D. A network that has only one entry and exit point. Answer: Option D Explanation: Stub networks have only one connection to an internetwork. Only default routes can be set on a stub network or network loops may occur.

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24.	If your router is facilitating a CSU/DSU, which of the following commands do you need to use to provide the router with a 64000bps serial link?
	A. RouterA(config)#bandwidth 64 B. RouterA(config-if)#bandwidth 64000 C. RouterA(config-if)#clock rate 64 D. RouterA(config-if)#clock rate 64000 Answer: Option D Explanation: The clock rate command is two words, and the speed of the line is in bps.

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25.

Which one of the following is true regarding VLANs?

A. Two VLANs are configured by default on all Cisco switches. B. VLANs only work if you have a complete Cisco switched internetwork. No off-brand switches are allowed. C. You should not have more than 10 switches in the same VTP domain. D. VTP is used to send VLAN information to switches in a configured VTP domain. Answer: Option D Explanation: Switches do not propagate VLAN information by default; you must configure the VTP domain. VLAN Trunking Protocol (VTP) is used to propagate VLAN information across a trunk link.

26.	What does a VLAN do?
	A. Acts as the fastest port to all servers. B. Provides multiple collision domains on one switch port. C. Breaks up broadcast domains in a layer 2 switch internetwork. D. Provides multiple broadcast domains within a single collision domain. Answer: Option C Explanation: VLANs break up broadcast domains at layer 2.

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27.	What is the main reason the OSI model was created?
	A. To create a layered model larger than the DoD model. B. So application developers can change only one layer's protocols at a time. C. So different networks could communicate. D. So Cisco could use the model. Answer: Option C Explanation: The primary reason the OSI model was created was so that different networks could inter-operate.

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28.	How many collision domains are created when you segment a network with a 12-port switch?
	A. 1 B. 2 C. 5 D. 12 Answer: Option D Explanation: Layer 2 switching creates individual collision domains.

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29.	What command will display the line, protocol, DLCI, and LMI information of an interface?
	A. sh pvc B. show interface C. show frame-relay pvc D. show run Answer: Option B Explanation: The show interface command shows the line, protocol, DLCI, and LMI information of an interface.

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30.	Which protocol does Ping use?
	A. TCP B. ARP C. ICMP D. BootP Answer: Option C Explanation: ICMP is the protocol at the Network layer that is used to send echo requests and replies.
31. What protocols are used to configure trunking on a switch? 1.    VLAN Trunking Protocol 2.    VLAN 3.    802.1Q 4.    ISL
A. 1 and 2 B. 3 and 4 C. 1 only D. 2 only Answer: Option B Explanation: VTP is not right because it has nothing to do with trunking except that it sends VLAN information across a trunk link. 802.1Q and ISL are used to configure trunking on a port.

1.	How many digits of the DNIC (Data Network Identification Code) identify the country?
	A. first three B. first four C. first five D. first six E. None of the above

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2.	A station in a network forwards incoming packets by placing them on its shortest output queue. What routing algorithm is being used?
	A. hot potato routing B. flooding C. static routing D. delta routing E. None of the above

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3.	The probability that a single bit will be in error on a typical public telephone line using 4800 bps modem is 10 to the power -3. If no error detection mechanism is used, the residual error rate for a communication line using 9-bit frames is approximately equal to
	A. 0.003 B. 0.009 C. 0.991 D. 0.999 E. None of the above

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4.	Frames from one LAN can be transmitted to another LAN via the device
	A. Router B. Bridge C. Repeater D. Modem

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5.	Which of the following condition is used to transmit two packets over a medium at the same time?
	A. Contention B. Collision C. Synchronous D. Asynchronous E. None of the above