Networking Interview Questions and Answers (2023)

In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission.

A network node is a connection point in a communications network. Each node is an endpoint for data transmissions or redistribution. Nodes have either a programmed or engineered capability to recognize, process and forward transmissions to other network nodes.

A point-to-point link-based system provides dedicated links between two devices. For example, a wired system that connects two computers together can be thought of as a point-to-point link.

A subnet mask is a 32-bit number created by setting host bits to all 0s and setting network bits to all 1s. In this way, the subnet mask separates the IP address into the network and host addresses.

Encapsulation is the process of adding additional information when data is traveling in OSI or TCP/IP model. The additional information has been added on sender's side, starting from Application layer to Physical layer.

VPN stands for "Virtual Private Network" and describes the opportunity to establish a protected network connection when using public networks. VPNs encrypt your internet traffic and disguise your online identity.

The physical layer sometimes plays an important role in the effective sharing of available communication resources, and helps avoid contention among multiple users. It also handles the transmission rate to improve the flow of data between a sender and receiver.

A private IP address is the address your network router assigns to your device. Each device within the same network is assigned a unique private IP address (sometimes called a private network address) — this is how devices on the same internal network talk to each other.

A Denial-of-Service (DoS) attack is an attack meant to shut down a machine or network, making it inaccessible to its intended users. DoS attacks accomplish this by flooding the target with traffic, or sending it information that triggers a crash. In both instances, the DoS attack deprives legitimate users (i.e. employees, members, or account holders) of the service or resource they expected.

A network operating system (NOS) is an operating system that manages network resources: essentially, an operating system that includes special functions for connecting computers and devices into a local area network (LAN).

Twisted-pair cable is a type of cabling that is used for telephone communications and most modern Ethernet networks. A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs.

The advantages of Distributed Processing are as follows:

• Security/Encapsulation
• Distributed database
• Faster Problem solving
• Security through redundancy
• Collaborative Processing

TCP/IP stands for Transmission Control Protocol/Internet Protocol and is a suite of communication protocols used to interconnect network devices on the internet. TCP/IP is also used as a communications protocol in a private computer network (an intranet or extranet).

The Hypertext Transfer Protocol (HTTP) is the foundation of the World Wide Web, and is used to load web pages using hypertext links. HTTP is an application layer protocol designed to transfer information between networked devices and runs on top of other layers of the network protocol stack.

A firewall is a network security system that is used to monitor the incoming and outgoing traffic and blocks the same based on the firewall security policies. It acts as a wall between the internet (public network) and the networking devices (private network). It can be a hardware device, software program, or a combination which adds a layer of security to the network.

Domain Name System (DNS) is a hierarchical naming system built on a distributed database for computers, services, or any resource connected to the Internet or a private network.

Serial Line Internet Protocol (SLIP) is the protocol which TCP/IP uses when operating through a serial connection.

Gateways provide connectivity between two or more network segments. It is usually a computer that runs the gateway software and provides translation services. This translation is critical in allowing different systems to communicate on the network.

In Domain Name System (DNS) terms, a DNS forwarder is a DNS server that is used to forward DNS queries for external DNS names to DNS servers outside that network. It does it to DNS queries that it cannot resolve locally, meaning DNS queries that it has no personal knowledge of.

Post Office Protocol 3, or POP3, is the most commonly used protocol for receiving email over the internet. This standard protocol, which most email servers and their clients support, is used to receive emails from a remote server and send to a local client.

A public IP address is an IP address that can be accessed directly over the internet and is assigned to your network router by your internet service provider (ISP). Your personal device also has a private IP that remains hidden when you connect to the internet through your router's public IP.

Anonymous File Transfer Protocol (FTP) enables remote users to use the FTP server without an assigned user ID and password. Anonymous FTP enables unprotected access (no password required) to selected information about a remote system. The remote site determines what information is made available for general access.

Routing Information Protocol (RIP) is a distance vector protocol that uses hop count as its primary metric. RIP defines how routers should share information when moving traffic among an interconnected group of local area networks (LANs).

Ping is a command-line utility, available on virtually any operating system with network connectivity, that acts as a test to see if a networked device is reachable. The ping command sends a request over the network to a specific device.

Multiplexing is a method used by networks to consolidate multiple signals- digital or analog, into a single composite signal that is transported over a common medium, such as a fiber optic cable or radio wave.

LAN stands for local area network. A network is a group of two or more connected computers, and a LAN is a network contained within a small geographic area, usually within the same building.

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.

Simple Mail Transfer Protocol (SMTP) is the standard protocol for email services on a TCP/IP network. SMTP provides the ability to send and receive email messages. SMTP is an application-layer protocol that enables the transmission and delivery of email over the Internet.

The Address Resolution Protocol (ARP) is a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address.

A Media Access Control address (MAC address) is a hardware identifier that uniquely identifies each device on a network. Primarily, the manufacturer assigns it. They are often found on a device's network interface controller (NIC) card.

Accessing resources shared by one of the workstations on the network can take a performance hit.

A hybrid network is any computer network that uses more than one type of connecting technology or topology. For example, a home network that uses both Wi-Fi and Ethernet cables to connect computers is a hybrid.

Routers have a built-in console that lets you configure different settings, like security and data logging. You can assign restrictions to computers, such as what resources it is allowed access or what particular time of the day, they can browse the Internet. You can even put restrictions on what websites are not viewable across the entire network.

Default gateways provide a way for the local networks to connect to the external network. The default gateway for connecting to the external network is usually the address of the external router port.

ICMP stands for Internet Control Message Protocol. It provides messaging and communication for protocols within the TCP/IP stack. This is also the protocol that manages error messages that are used by network tools such as PING.

A fiber optics setup is less susceptible to electrical interference. It supports higher bandwidth and signal degrading is minimal over long distances.

Ipconfig is a utility program that is commonly used to identify the addresses information of a computer on a network. It can show the physical address as well as the IP address.

Clustering support refers to the ability of a network operating system to connect multiple servers in a fault-tolerant group. The main purpose is that if one server fails, all processing will continue with the next server in the cluster.

SMTP stands for Simple Mail Transfer Protocol. This protocol focuses on all internal mail and provides the necessary mail delivery services on the TCP/IP protocol stack.

Authentication is the process of verifying a user’s credentials before they can log into the network. It provides a secure means of limiting access from unwanted intruders on the network.

Tunnel Mode is a method of sending data over the Internet where the data is encrypted and the original IP address information is also encrypted. The Encapsulating Security Payload (ESP) operates in Transport Mode or Tunnel Mode. In Tunnel Mode, ESP encrypts the data and the IP header information.

The RSA algorithm is an asymmetric cryptography algorithm; this means that it uses a public key and a private key (i.e two different, mathematically linked keys).

NVT stands for Network Virtual Terminal. NVT is a set of pre-defined rules for very simple virtual terminal interaction. This terminal helps you start a Telnet session.

Multihomed describes a computer host that has multiple IP addresses to connected networks. A multihomed host is physically connected to multiple data links that can be on the same or different networks.

Hamming code is used for the set of error-correction codes which may occur when the data is moved from the sender to the receiver. The hamming method corrects the error by finding the state at which the error occurred.

A modem is a device that receives an analog signal from your internet service provider (ISP) and translates it into a digital signal that your devices can understand and vice versa. This allows your devices to send and receive data over the internet.