Category: Computer Networks Objective Questions

Computer Networks Multiple Choice Questions on “IPv6”.

1. The size of an IP address in IPv6 is _________
a) 4 bytes
b) 128 bits
c) 8 bytes
d) 100 bits

Answer: b
Clarification: An IPv6 address is 128 bits long. Therefore, 2128 i.e. 340 undecillion addresses are possible in IPv6. IPv4 has only 4 billion possible addresses and IPv6 would be a brilliant alternative in case IPv4 runs out of possible new addresses.

2. The header length of an IPv6 datagram is ___________
a) 10bytes
b) 25bytes
c) 30bytes
d) 40bytes

Answer: d
Clarification: IPv6 datagram has fixed header length of 40bytes, which results in faster processing of the datagram. There is one fixed header and optional headers which may or may not exist. The fixed header contains the mandatory essential information about the packet while the optional headers contain the optional “not that necessary” information.

3. In the IPv6 header, the traffic class field is similar to which field in the IPv4 header?
a) Fragmentation field
b) Fast-switching
c) ToS field
d) Option field

Answer: c
Clarification: The traffic class field is used to specify the priority of the IP packet which is a similar functionality to the Type of Service field in the IPv4 header. It’s an 8-bit field and its values are not defined in the RFC 2460.

4. IPv6 does not use _________ type of address.
a) broadcast
b) multicast
c) anycast
d) unicast

Answer: a
Clarification: There is no concept of broadcast address in IPv6. Instead, there is an anycast address in IPv6 which allows sending messages to a group of devices but not all devices in a network. Anycast address is not standardized in IPv4.

5. Which among the following features is present in IPv6 but not in IPv4?
a) Fragmentation
b) Header checksum
c) Options
d) Anycast address

Answer: d
Clarification: There is an anycast address in IPv6 which allows sending messages to a group of devices but not all devices in a network. Anycast address is not standardized in IPv4.

6. The _________ field determines the lifetime of IPv6 datagram
a) Hop limit
b) TTL
c) Next header
d) Type of traffic

Answer: a
Clarification: The Hop limit value is decremented by one by a router when the datagram is forwarded by the router. When the value becomes zero the datagram is discarded. The field is 8-bits wide, so an IPv6 packet can live up to 255 router hops only.

7. Dual-stack approach refers to _________
a) implementing Ipv4 with 2 stacks
b) implementing Ipv6 with 2 stacks
c) node has both IPv4 and IPv6 support
d) implementing a MAC address with 2 stacks

Answer: c
Clarification: Dual-stack is one of the approaches used to support IPv6 in already existing systems. ISPs are using it as a method to transfer from IPv4 to IPv6 completely eventually due to the lower number of possible available addresses in IPv4.

8. Suppose two IPv6 nodes want to interoperate using IPv6 datagrams, but they are connected to each other by intervening IPv4 routers. The best solution here is ________
a) Use dual-stack approach
b) Tunneling
c) No solution
d) Replace the system

Answer: b
Clarification: The IPv4 routers can form a tunnel in which at the sender’s side, the IPv6 datagram is encapsulated in to IPv4, and at the receiver’s side of the tunnel, the IPv4 packet is stripped and the IPv6 packet is sent to the receiver.

9. Teredo is an automatic tunneling technique. In each client the obfuscated IPv4 address is represented by bits ______
a) 96 to 127
b) 0 to 63
c) 80 to 95
d) 64 to 79

Answer: a
Clarification: Teredo is a technique through which gives the possibility for full IPv6 network connectivity to IPv6 capable hosts which are currently on an IPv4 network. Bits 96 to 127 in the datagram represents obfuscated 1Pv4 address of the IPv4 network.

Computer Networks online test on “Packet Forwarding and Routing”.

1. The term that is used to place packet in its route to its destination is called __________
a) Delayed
b) Urgent
c) Forwarding
d) Delivering

Answer: c
Clarification: Forwarding is done by the nodes in the path from source to destination, that are not the intended destination for the packet in order to pass the packet to the next node in the path. The destination machine does not forward the packet to any other node.

2. A second technique to reduce routing table and simplify searching process is called _________
a) Network-Specific Method
b) Network-Specific Motion
c) Network-Specific Maintaining
d) Network-Specific Membership

Answer: a
Clarification: In the network specific forwarding method, there is only one record, the destination of the packet, in the routing table and not the other hosts of the network. The other two forwarding methods are the default method and the next-hop method.

3. Next-Hop Method is used to reduce contents of a _________
a) Revolving table
b) Rotating Table
c) Routing Table
d) Re-allocate table

Answer: c
Clarification: In the next-hop forwarding method, the routing table of each router in the path contains the address of only the next hop in the path of packet. This method is suitable for short distances only.

4. Several techniques can make size of routing table manageable and also handle issues such as __________
a) Maturity
b) Error reporting
c) Tunneling
d) Security

Answer: d
Clarification: The size of the routing table in the technique must be manageable for the network nodes i.e. it must not be too big. Security of the forwarding packet is the highest priority for a technique and must be high enough so that only authorized senders and receivers can access the packet’s content.

5. Host-specific routing is used for purposes such as checking route or providing _____
a) Network Measures
b) Security Measures
c) Routing Measures
d) Delivery Measures

Answer: b
Clarification: In host-specific routing, the route of the packet is defined based on the exact match of the packet’s IP with the routing table entry of the host. It provides the best security for the packet as the packet is forwarded only to routers in the pre-defined path.

6. In Unicast routing, if instability is between three nodes, stability cannot be ________
a) Stable
b) Reversed
c) Guaranteed
d) Forward

Answer: c
Clarification: In Unicast routing, there is only sender and one receiver. So, if there is instability between three nodes, in which one is sender, one is receiver and one is the router in the path, there is no other path available for the packet and the stability of the network is not guaranteed.

7. In Unicast Routing, Dijkstra algorithm creates a shortest path tree from a ________
a) Graph
b) Tree
c) Network
d) Link

Answer: a
Clarification: The Djikstra’s shortest path algorithm is the fastest among the algorithms for finding the shortest path in a graph. But it is a greedy method based algorithm so it does not guarantee the shortest path every time.

8. In Multicast Routing Protocol, flooding is used to broadcast packets but it creates ________
a) Gaps
b) Loops
c) Holes
d) Links

Answer: b
Clarification: In multicast routing, there is one sender and many receivers. So flooding is the most basic method to forward packets to many receivers. The one issue with flooding is that it creates routing loops. One loop prevention method is that the routers will not send the packet to a node where the packet has been received before.

9. RPF stands for __________
a) Reverse Path Forwarding
b) Reverse Path Failure
c) Reverse Packet Forwarding
d) Reverse Protocol Failure

Answer: a
Clarification: Reverse Path Forwarding is a loop-free forwarding method for multi-cast routing in modern systems. The method on forwarding the packet away from the source IP in each iteration to make sure there is no loops.

10. LSP stands for __________
a) Link Stable Packet
b) Link State Packet
c) Link State Protocol
d) Link State Path

Answer: b
Clarification: A Link State Packet is a packet created by a router that lists its neighboring nodes and routers in link state routing protocol. It is shared with other routers to find the shortest path from a source to the destination.

Computer Networks Questions and Answers for Campus interviews on “STP (Shielded Twisted Pair) Cables”.

1. _____________ allows LAN users to share computer programs and data.
a) Communication server
b) Print server
c) File server
d) Network

Answer: c
Clarification: A file server allows LAN users to share computer programs and data. It uses the File Transfer Protocol to provide this feature on ports 20 and 21. The file server works as a medium for the transfer.

2. With respect to physical media, STP cables stands for _________
a) Shielded Twisted Pair Cable
b) Spanning Tree Protocol Cable
c) Static Transport Protocol Cable
d) Shielded Two Power Cable

Answer: a
Clarification: For physical media, STP cable stands for Shielded twisted pair cable. 100 Mbps is the max data capacity of STP cable and its default connector is RJ45. It is popularly used in LANs due to its ease of maintenance and installation.

3. A standalone program that has been modified to work on a LAN by including concurrency controls such as file and record locking is an example of ___________
a) LAN intrinsic software
b) LAN aware software
c) Groupware
d) LAN ignorant software

Answer: a
Clarification: A standalone program that has been modified to work on a LAN by including concurrency controls such as file and record locking is an example of LAN intrinsic software. They are used to give better functionality of the program and the applications working over it to the users of the LAN.

4. The __________ portion of LAN management software restricts access, records user activities and audit data, etc.
a) Configuration management
b) Security management
c) Performance management
d) Recovery management

Answer: b
Clarification: The Security management portion of LAN management software restricts access, records user activities, and audit data. It is responsible for controlling access to the network based on predefined policy. The security management ensures authentication, confidentiality, and integrity in the LAN.

5. What is the max length of the Shielded twisted pair cable?
a) 100 ft
b) 200 ft
c) 100 m
d) 200 m

Answer: c
Clarification: The max the Shielded twisted pair cable is 100 meters. If the length exceeds 100 meters, the loss of signals flowing through the cable would be really high. Thus, STP cable is more suitable for smaller networks like LANs.

6. What is the max data transfer rate of STP cables?
a) 10 Mbps
b) 100 Mbps
c) 1000 Mbps
d) 10000 Mbps

Answer: b
Clarification: 100 Mbps is the max data transfer rate that can be handled by STP cables, and its default connector is RJ-45. 100 Mbps is a feasible data transfer rate for small networks like LANs.

7. Which connector does the STP cable use?
a) BNC
b) RJ-11
c) RJ-45
d) RJ-69

Answer: c
Clarification: RJ-45 is used for STP cable. 100 Mbps is the max data transfer rate that can be handled by STP. RJ-45 is popularly used to connect to modern-day routers, computer network cards, and other network devices.

8. What is the central device in star topology?
a) STP server
b) Hub/switch
c) PDC
d) Router

Answer: b
Clarification: In star topology, no computer is connected to another computer directly but all the computers are connected to a central switch or hub. Every message sent from a source computer goes through the switch or hub and the switch or hub then forwards the message only to the intended destination computer.

9. What is the max data transfer rate for optical fiber cable?
a) 10 Mbps
b) 100 Mbps
c) 1000 Mbps
d) 10000 Mbps

Answer: d
Clarification: Fiber channel speeds have been increasing over the years. 10000 Mbps is the max data transfer rate for optical fiber cables. It is said to be the fastest among the other kinds of cables like STP cables and co-axial cables. People are now using optical fiber cables instead of STP cables for LANs due to their fast data transfer capability.

10. Which of the following architecture uses the CSMA/CD access method?
a) ARC net
b) Ethernet
c) Router
d) STP server

Answer: b
Clarification: Collision detection is not possible in Ethernet without extensions. Collision detection techniques for multiple access like CSMA/CD are used to detect collisions in the Ethernet architecture.

Computer Networks Questions and Answers for Freshers on “SMI”.

1. Storage management comprises of _______________
a) SAN Management
b) Data protection
c) Disk operation
d) All of the mentioned

Answer: d
Clarification: SAN management, data protection and disk operation are the main components of the Storage Management Initiative Specification. SMI-S was developed by the Storage Networking Industry Association.

2. Which of the following is not a storage device?
a) Switch
b) RAID Arrays
c) Tape drives
d) Hub

Answer: d
Clarification: Switches, RAID arrays and tape drives are the main storage devices in SMI-S, while a Hub is simple networking device that cannot be used as storage.

3. Which protocols are used for Storage management?
a) SNMP
b) LDAP
c) POP3
d) MIB

Answer: a
Clarification: Simple Network Management Protocol is used for storage management. Lightweight Directory Access Protocol is used to access or locate information about directories and other resources on a network. Post Office Protocol 3 is used for e-mailing on the internet. Management Information Base is a part of SNMP and contains hierarchically organized information.

4. Identify the difficulty a SAN administrator does not incur while dealing with diverse vendors.
a) Proprietary management interfaces
b) Multiple applications to manage storage in the data center
c) No single view
d) Single view

Answer: d
Clarification: A single view is not possible with diverse vendors present. Proprietary management interfaces, multiple applications management and no single view are the main difficulties incurred by a SAN administrator in such a situation.

5. How do Storage administrators ensure secure access to storage devices?
a) By using Zoning
b) By putting a physical lock on the storage device
c) By keeping devices shutdown when not in use
d) By keeping devices when used

Answer: a
Clarification: Zoning is a method in SAN that can be used by a storage administrator to specify who can see what in the SAN. Zoning might complicate the scaling process if the size of the SAN increases.

6. Effective Storage management does not include __________
a) security
b) backups
c) reporting
d) connection

Answer: d
Clarification: Connection is the responsibility of the connection manager. Storage management includes management of all necessities such as security, backups and reporting facilities.

7. Among the following, identify which task is not involved in Storage Capacity management?
a) Identifying storage systems are approaching full capacity
b) Monitoring trends for each resource
c) Tracking Total capacity, total used, total available
d) Preventing unauthorized access to the storage

Answer: d
Clarification: Prevention of unauthorized access to storage is the task of Security management. Identifying when the storage is approaching full capacity, monitoring trends, reporting and tracking capacity are the tasks of Storage Capacity management.

8. Effect of open standards like SMI(s) is _______________
a) standardization drives software interoperability and interchange ability
b) breaks the old-style dependence on proprietary methods, trade secrets, and single providers
c) builds a strong foundation on which others can quickly build and innovate
d) all of the mentioned

Answer: d
Clarification: Open standards like SMI-S inculcate a general ideal through which the normal designers are able to easily implement the standard into their software and its scalability. Since it is open-source, nothing is hidden from its users and they can implement it as they like or require to. As a whole lot of time is spent to build it as strong and scalable, it provides an efficient foundation to the designers to build and innovate on.

9. Task of Distributed Management Task Force is not ________
a) to promote interoperability among the management solution providers
b to act as an interface between the various budding technologies and provide solution to manage various environments
c) to track the operation of the different management solution providers
d) to manage the facility by itself if one of the management solution providers fail

Answer: d
Clarification: The Distributed Management Task Force is used just to simplify the overall management of the network. It cannot manage a network facility by itself in case one of the management solution providers fails. It provides an interface for promoting interoperability among management solution providers.

10. SMI-S Standard uses which of the following?
a) Java RMI
b) CIM-XML/HTTP
c) CORBA
d) .NET

Answer: b
Clarification: The Distributed Management Task Force maintains a Common Information Model (CIM) to represent a common set of network objects and their relationships. CIM-XML/HTTP refers to the operations of CIM being performed over HTTP or XML. SMI-S uses CIM-XML/HTTP.

Computer Networks test on “IPv6 Addressing”.

1. Dual-stack approach refers to _________
a) Implementing Ipv4 with 2 stacks
b) Implementing Ipv6 with 2 stacks
c) Node has both IPv4 and IPv6 support
d) Implementing a MAC address with 2 stacks

Answer: c
Clarification: Dual-stack is one of the approaches used to support IPv6 in already existing systems. ISPs are using it as a method to transfer from IPv4 to IPv6 completely eventually due to the lower number of possible available addresses in IPv4.

2. Suppose two IPv6 nodes want to interoperate using IPv6 datagrams, but they are connected to each other by intervening IPv4 routers. The best solution here is ________
a) Use dual-stack approach
b) Tunneling
c) No solution
d) Replace the system

Answer: b
Clarification: The IPv4 routers can form a tunnel in which at the sender’s side, the IPv6 datagram is encapsulated in to IPv4, and at the receiver’s side of the tunnel, the IPv4 packet is stripped and the IPv6 packet is sent to the receiver.

3. Teredo is an automatic tunneling technique. In each client the obfuscated IPv4 address is represented by bits ______
a) 96 to 127
b) 0 to 63
c) 80 to 95
d) 64 to 79

Answer: a
Clarification: Teredo is a technique through which gives the possibility for full IPv6 network connectivity to IPv6 capable hosts which are currently on an IPv4 network. Bits 96 to 127 in the datagram represents obfuscated 1Pv4 address of the IPv4 network.

4. A link local address of local addresses is used in an _______
a) Isolated router
b) Isolated mask
c) Isolated subnet
d) Isolated net

Answer: c
Clarification: Isolated subnet is very huge sharing network area in this link local address of local addresses is used. A link local address can be configured on any subnet with the prefix “FE80::”.

5. In subcategories of reserved address in IPv6, address that is used by a host to test itself without going into network is called _________
a) Unspecified address
b) Loopback address
c) Compatible address
d) Mapped address

Answer: b
Clarification: In subcategories of reserved address in IPv6, address that is used by a host to test itself without going into network is called loop back address. IPv6 loopback address is 0000:0000:0000:0000:0000:0000:0000:0001. IPv4 loopback address is 127.0.0.1. It’s a reserved address.

6. A few leftmost bits in each address of IPv6 address define its category is called ________
a) Prefix type
b) Postfix type
c) Reserved type
d) Local type

Answer: a
Clarification: Prefix is the bits in the IP address which are placed in leftmost position. A network prefix in IPv6 is given by a CIDR format-liked number at the end of the address.

7. In IPv6 addresses, addresses that start with eight 0s are called ________
a) Unicast addresses
b) Multicast addresses
c) Any cast addresses
d) Reserved addresses

Answer: d
Clarification: In IPv6 address format, the starting bits are specified with eight 0s to represent reserved addresses. These reserved addresses have a certain function pre-defined like the loop-back address is used to test a network card. Reserved addresses cannot be allotted to a machine.

8. Which statement(s) about IPv6 addresses are true?
a) Leading zeros are required
b) Two colons (::) are used to represent successive hexadecimal fields of zeros
c) Two colons (::) are used to separate fields
d) A single interface cannot have multiple IPv6 addresses of different types

Answer: b
Clarification: In order to shorten the written length of an IPv6 address, successive fields of zeros may be replaced by double colons. In trying to shorten the address further, leading zeros may also be removed. Just as with IPv4, a single device’s interface can have more than one address; with IPv6 there are more types of addresses and the same rule applies. There can be link-local, global unicast, and multicast addresses all assigned to the same interface.

9. When was IPv6 launched?
a) June 2, 2012
b) June 4, 2012
c) June 5, 2012
d) June 6, 2012

Answer: d
Clarification: IPv6 is the latest version of the Internet Protocol released on 6^th June 2012. An IPv6 address is 128 bits long. Therefore, 2¹²⁸ i.e. 340 undecillion addresses are possible in IPv6.

Computer Networks Multiple Choice Questions on “Security In The Internet”.

1. IPSec is designed to provide security at the _________
a) transport layer
b) network layer
c) application layer
d) session layer

Answer: b
Clarification: IPSec is a set of protocols used to provide authentication, data integrity and confidentiality between two machines in an IP network. In the TCP/IP model, it provides security at the IP layer i.e. the network layer.

2. In tunnel mode, IPSec protects the ______
a) Entire IP packet
b) IP header
c) IP payload
d) IP trailer

Answer: a
Clarification: In the tunnel mode, IPSec adds control bits into the packets to encrypt the entire packet between the IPSec endpoints. Using encryption, it provides secure communication between the two endpoints.

3. Network layer firewall works as a ________
a) frame filter
b) packet filter
c) signal filter
d) content filter

Answer: b
Clarification: As you know, firewalls are available as hardware appliances, as software-only, or a combination of the two. In every case, the purpose of a firewall is to isolate your trusted internal network (or your personal PC) from the dangers of unknown resources on the Internet and other network connections that may be harmful. The firewall prevents unauthorized access to your internal, trusted network from outside threats.

4. Network layer firewall has two sub-categories called ____________
a) stateful firewall and stateless firewall
b) bit oriented firewall and byte oriented firewall
c) frame firewall and packet firewall
d) network firewall and data firewall

Answer: a
Clarification: Most network layer firewalls can operate as stateful or stateless firewalls, creating two subcategories of the standard network layer firewall. Stateful firewalls have the advantage of being able to track packets over a period of time for greater analysis and accuracy — but they require more memory and operate more slowly. Stateless firewalls do not analyze past traffic and can be useful for systems where speed is more important than security, or for systems that have very specific and limited needs. For example, a computer that only needs to connect to a particular backup server does not need the extra security of a stateful firewall.

5. WPA2 is used for security in _______
a) ethernet
b) bluetooth
c) wi-fi
d) e-mail

Answer: c
Clarification: WPA2 or WiFi Protected Access 2 is a security protocol used to provide users and firms with strong data security and protection for their wireless networks (WiFi) to give them confidence that only authorized users can access their network.

6. An attempt to make a computer resource unavailable to its intended users is called ______
a) denial-of-service attack
b) virus attack
c) worms attack
d) botnet process

Answer: a
Clarification: In a Denial of Service attack, the attacker won’t let the victims access the network by using a certain method that ensures that an essential network resource is unavailable to the victim. The methods that the attacker can use are vulnerability attack, bandwidth flooding and connection flooding.

7. Extensible authentication protocol is authentication framework frequently used in ______
a) wired personal area network
b) wireless networks
c) wired local area network
d) wired metropolitan area network

Answer: b
Clarification: The Extensible Authentication Protocol (EAP) is an authentication protocol used to connect a network node to the Internet. It designed through extending the methods used by the Point-to-Point Protocol for authentication.

8. Pretty good privacy (PGP) is used in ______
a) browser security
b) email security
c) FTP security
d) wifi security

Answer: b
Clarification: PGP is an encryption method used in e-mail security to encrypt and decrypt the content of an e-mail transmitted over the internet. It makes sure that the message cannot be stolen by other unauthorized users.

9. PGP encrypts data by using a block cipher called ______
a) international data encryption algorithm
b) private data encryption algorithm
c) internet data encryption algorithm
d) local data encryption algorithm

Answer: a
Clarification: The IDEA was designed in 1991 by Xuejia Lai and James Massey. Before IDEA, PGP used the cipher method BassOmatic.

10. When a DNS server accepts and uses incorrect information from a host that has no authority giving that information, then it is called _________
a) DNS lookup
b) DNS hijacking
c) DNS spoofing
d) DNS authorizing

Answer: c
Clarification: In DNS spoofing, also known as DNS cache poisoning, an attacker gets the valid credentials from a victim by spoofing the intended resource, and tricking the victim to give his/her valid authorization credentials.