Computer Knowledge

Computer Networks

2,614 Questions

Computer networks involve the architecture, protocols, and security measures used for digital communication. This collection covers OSI model layers, IP addressing, data transmission, and cryptographic standards. These concepts are vital for the computer knowledge sections of banking and government exams.

OSI model layersNetwork protocolsIP subnet maskingData encryption standardsServer configurationsNetwork commands

Computer Networks Questions

Multiple choice

Which of the following application layer protocols can be used for downloading an email from a mailbox server to a user-level mail client?

Fourth-generation firewalls operate up to layer 4 (transport layer) of the OSI model.

  1. SMTP

  2. HTTP

  3. TELNET

  4. IMAP

  5. Webmail
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Internet Message Access Protocol (commonly known as IMAP) is an application layer internet protocol that allows an e-mail client to access e-mail on a remote mail server.

Multiple choice

Which of the following functions cannot be accomplished by the fourth-generation firewalls?

Fourth generation firewalls operate upto layer 4 (transport layer) of the OSI model.

  1. Block ICMP packets

  2. Understand FTP

  3. Block incoming traffic from a specific user on a single user system

  4. Block outgoing traffic to a specific IP address on a single user system

  5. Block TCP traffic from a specific user on a multi-user system
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A fourth generation firewall cannot understand FTP as FTP operates in application layer, which resides higher than transport layer. A fourth-generation firewall can understand protocols upto layer 4 only.

Multiple choice

What type of protocol is IPv4?

  1. Connectionless for use on packet-switched networks

  2. Connection oriented for use on packet-switched networks

  3. Connection oriented for use on circuit-switched networks

  4. Connectionless for use on circuit-switched networks

  5. Connection oriented for use on virtual circuit switching networks
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

IPv4 is a connectionless protocol for use on packet-switched networks. It operates on a best effort delivery model, in that it does not guarantee delivery, nor does it assure proper sequencing or avoidance of duplicate delivery. These aspects, including data integrity, are addressed by an upper layer transport protocol, such as the Transmission Control Protocol (TCP).

Multiple choice

Which of the following is an error control method for data transmission to achieve reliable data transmission over an unreliable service?

  1. BGP

  2. RIP

  3. ARQ

  4. ARP

  5. NDP
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Automatic Repeat reQuest (ARQ), is an error-control method for data transmission that uses acknowledgements (messages sent by the receiver indicating that it has correctly received a data frame or packet) and timeouts (specified periods of time allowed to elapse before an acknowledgment is to be received) to achieve reliable data transmission over an unreliable service. If the sender does not receive an acknowledgment before the timeout, it usually re-transmits the frame/packet until the sender receives an acknowledgment or exceeds a predefined number of re-transmissions.

Multiple choice

Which of the following protocols can be used for managing networks?

  1. Gopher

  2. NETCONF

  3. Finger

  4. NFS

  5. DNS
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Network Configuration Protocol (NETCONF), is an IETF network management protocol.NETCONF provides mechanisms to install, manipulate, and delete the configuration of network devices. Its operations are realized on top of a simple Remote Procedure Call (RPC) layer.

Multiple choice

Which of the following is not true regarding TCP connections?

  1. TCP connections are full-duplex.

  2. TCP connections are point-to-point.

  3. TCP connections support multicasting.

  4. TCP connections do not support broadcasting.

  5. TCP connections are byte stream.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Since each connection has exactly two end points, therefore, multicasting is not possible with this connection.

Multiple choice

Which OSI layer connects hosts within the same network?

  1. Physical layer

  2. Data link layer

  3. Network layer

  4. Transport layer

  5. Session layer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The data link layer provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the physical layer. It connects hosts within the same network.

Multiple choice

Which field of the IP header helps to prevent datagrams from persisting on an internet?

  1. Destination address

  2. Source address

  3. Flag

  4. TTL

  5. Header checksum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An eight-bit time to live field helps prevent datagrams from persisting (e.g. going in circles) on an internet. This field limits a datagram's lifetime. It is specified in seconds, but time intervals less than 1 second are rounded up to 1. In practice, the field has become a hop count—when the datagram arrives at a router, the router decrements the TTL field by one. When the TTL field hits zero, the router discards the packet and typically sends an ICMP Time Exceeded message to the sender.

Multiple choice

Which of the following protocols is used when the delivery protocol encapsulates a different payload protocol?

Users can sometimes sneak through a firewall, using a protocol that the firewall would normally block, but wrapped inside a protocol that the firewall does not block, such as HTTP. If the firewall policy does not specifically exclude this kind of wrapping, this trick can function to get around the intended firewall policy.

  1. Proxy server

  2. HTTP

  3. Firewall

  4. Tunneling

  5. Pseudo wire
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Computer networks use a tunneling protocol when one network protocol (the delivery protocol) encapsulates a different payload protocol. By using tunneling one can (for example) carry a payload over an incompatible delivery-network, or provide a secure path through an untrusted network.

Multiple choice

Which of the following IP address classes uses 3 network ID bits to identify class?

  1. Class A

  2. Class B

  3. Class C

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a class C, IP address; the first three bytes represent the network. The first three bits are 1,1 and 0 which mean that there are 221 network possibilities, i.e. 2,097,152. The networks available in class C are networks going from 192.0.0.0 to 223.255.255.0. Therefore, it uses three network IDs to identify the class.