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Top 25 Networking Job Interview Questions in 2020/2021

System Administrators, Network Administrators, Windows Server Administrator, Network Engineers and Hardware Engineers are the key part of any organization’s IT team. They are responsible for planning, constructing, implementing, maintaining, supporting, developing, and, in some cases, designing communication networks within an organization or between organizations. Their goal is to ensure the integrity of high availability network infrastructure to provide maximum performance for their users.

Jobs that require networking skills is increasing at a faster speed with tangible growth rates over the past few years and is expected that the market will grow remarkably in the anticipated period i.e. 2020 to 2027. Companies look for expert professionals who can handle their networking requirements efficiently. There are a lot of opportunities for such professionals in the industry. Various courses are depending on the level of expertise – beginner, intermediate, or advanced.

If you are applying for a job of System Administrator, Network Administrator, Windows Server Administrator or Network Engineer you might be asked computer network interview questions, which would test your technical knowledge and understanding of computer network. Even though every interview is different as per the different job profiles the questions asked might be very similar. In this post we summarized the most typical Computer Network Interview Questions and Answers which will help you get ready and pass your interview.

Top 25 Networking Interview questions in 2020

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A network node typically refers to a endp-point or joint where a network connection takes place. It can be a computer or device that is part of a network. Two or more nodes are needed to form a network connection. Typically a physical electronic communication device that is attached to a network, using connection provided by the node, and is capable of creating, receiving, or transmitting information over a communication channel through the access provide by the node.

A few examples of nodes include computers, printers, modems, bridges, and switches or other electronic devices, connected to the network

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OSI - Open System Interconnection

The OSI Model (Open Systems Interconnection Model) is a conceptual framework used to describe the functions of a networking system.

The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software. In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Application, Presentation, Section, Transport, Network, Data Link, Physical.

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LAN stands for Local Area Network. It refers to the connection between computers and other networking devices that are located within a small physical location such as room, building, small business office, or home.

A LAN can be small or large, ranging from a home network with one user to an enterprise network with thousands of users and devices in an office or school and typicall LAN interconnects computers within a limited area such as a residence, school or office building.

By contrast, a WAN - Wide Area Network not only covers a larger geographic distance, but also generally involves leased telecommunication circuits.

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A backbone network is a centralized infrastructure that is designed to distribute different routes and data to various networks. It also handles the management of bandwidth and multiple channels.

backbone or core network is a part of  typical computer network which connects together pieces of various networks, providing a path for the exchange of information between different LANS. A backbone can tie together diverse networks in the same building, in different buildings in a campus environment, or over wide areas. Normally, the backbone's capacity is greater than the networks connected to it


Data encapsulation is the process of breaking down information into smaller, manageable chunks before it is transmitted across the network. In this process that the source and destination addresses are attached to the headers, along with parity checks.

  • Breaking down information
  • Smaller
  • Manageable chunks
  • Transmitted across the network.
  • Source addresses
  • Destination addresses are
  • Headers,
  • Parity checks


OSPF, or Open Shortest Path First, is a link-state routing protocol that uses routing tables to determine the best possible path for data exchange.

  • Open shortest path first
  • Link-state routing protocol
  • Routing tables
  • Best possible path
  • Data exchange.

NAT is Network Address Translation.  This is a protocol that provides a way for multiple computers on a common network to share a single connection to the Internet.

  • Network address translation.
  • Protocol
  • Multiple computers
  • Common

Routers can connect two or more network segments.
These are intelligent network devices that store information in their routing tables, such as paths, hops, and bottlenecks.
With this info, they can determine the best path for data transfer. Routers operate at the OSI network layer.

  • Connect two or more network segments.
  • Intelligent network devices
  • Store information
  • Routing tables,
  • Paths,
  • Hops,
  • Bottlenecks.
  • Best path
  • Data transfer.
  • OSI network layer.

A subnet mask is combined with an IP address to identify two parts: The extended network address, The host address. Like an IP address, a subnet mask is made up of 32 bits.

  • Combined with an IP address
    • Identify two parts:
    • Extended network address,
  • Host address.
  • Like an IP address
  • 32 bits.


Anonymous FTP is a way of granting user access to files in public servers.
Users that are allowed access to data in these servers do not need to identify themselves, but instead, log in as an anonymous guest.

  • Granting user access
  • Files
  • Public servers.
  • Allowed access
  • Identify themselves,
  • Log in as an anonymous guest.

RIP, short for Routing Information Protocol it’s used by routers to send data from one network to another. It efficiently manages routing data by broadcasting its routing table to all other routers within the network. It determines the network distance in units of hops.

  • Routing information protocol
  • Routers
  • Send data
  • Manages routing data
  • Broadcasting
  • Routing table.
  • Network distance
  • Units - hops.


VPN means Virtual Private Network. VPN is a technology that allows a secure tunnel to be created across a network such as the Internet.  For example, VPNs allow you to establish a secure dial-up connection to a remote server.

  • Virtual private network.
  • Technology
  • Allows a secure tunnel to be created
  • Internet.
  • For example,
    • A dial-up connection to a remote server.

The OSI model describes idealized network communication with a family of protocols. TCP/IP does not correspond to this model directly. TCP/IP either combines several OSI layers into a single layer or does not use certain layers at all.

There are four layers:

  • The Network Layer,
  • Internet Layer,
  • Transport Layer,
  • Application Layer.

NOS, or Network Operating System, is specialized software. The main task of this software is to provide network connectivity to a computer in order to communicate with other computers and connected devices.

  • Network operating system,
  • Specialized software.
  • Network connectivity
  • Communicate with other

The 10 refers to the data transfer rate. In this case, it is 10Mbps.  The word Base refers to baseband, as opposed to broadband.

  • 10
    • refers to the data transfer rate.
  • 10Mbps.
    • Base
    • baseband, as opposed to broadband.


A single segment of UTP cable has an allowable length of 90 to 100 meters. This limitation can be overcome by using repeaters and switches.

  • Single-segment
  • Length of 90 to 100 meters
  • Repeaters
  • Switches

Proxy servers primarily prevent external users who are identifying the IP addresses of an internal network.  Without knowledge of the correct IP address, even the physical location of the network cannot be identified.  Proxy servers can make a network virtually invisible to external users.

  • Proxy servers primarily prevent external users who are identifying the IP addresses of an internal network.
  • Without knowledge of the correct IP address, even the physical location of the network cannot be identified.
  • Proxy servers can make a network virtually invisible to external users.


Network Topology refers to the layout of a computer network.  It shows how devices and cables are physically laid out, as well as how they connect.

  • The layout of a computer network.
  • Devices
  • Cables
  • Physically laid out
  • Connect.

NIC is short for Network Interface Card.  This is a peripheral card that is attached to a PC in order to connect to a network.  Every NIC has its own MAC address that identifies the PC on the network.

  • Network interface card.
  • Peripheral card
  • Connect to a network.
  • Mac address

A fault tolerance system ensures continuous data availability. This is done by eliminating a single point of failure.

  • continuous data availability.
  • eliminating a single point of failure.

WAN stands for Wide Area Network.  It is an interconnection of computers and devices that are geographically dispersed.  It connects networks that are located in different regions and countries.

  • Wide area network.
  • Interconnection of
  • Geographically dispersed.
  • Regions
  • Countries

Private IP addresses are assigned for use on intranets.  These addresses are used for internal networks and are not routable on external public networks.  These ensure that no conflicts are present among internal networks.  At the same time, the same range of private IP addresses is reusable for multiple intranets since they do not "see" each other.

  • use on intranets.
  • internal networks
  • routable on external public networks.
  • no conflicts are present among internal networks.
  • reusable


This layer provides the protocols and means for two devices on the network to communicate with each other by holding a session. This includes setting up the session, managing information exchange during the session, and tear-down the process upon termination of the session.

  • The session is created when devices need to talk to each other.
  • Involves Setup, Coordination & Termination

About the Author

Vadim Mikhailenko, MBA

Vadim lives in Milwaukee, Wisconsin and works as an Information Technology Consultant, Coach and Educator. Vadim is very passionate about Milwaukee community and teaches classes to underprivileged students at local community college to help them get employed. Throughout his consulting career Vadim studied a lot of tools and technologies and learned hiring process by helping organizations to hire candidates and also supported students to get prepared and to pass interview and assessment tests.

Vadim loves to share his knowledge with and enjoys teaching  new skills to help you get hired for your dream job.

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