computer networks Interview Questions

Question 1: What is a computer network?
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A computer network is a set of interconnected computers that communicate with each other and share resources, such as files, printers, and internet connections.

Question 2: What are the types of computer networks?
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The main types of computer networks include: LAN (Local Area Network), WAN (Wide Area Network), MAN (Metropolitan Area Network), PAN (Personal Area Network), and CAN (Campus Area Network).

Question 3: What is the OSI model?
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The OSI model (Open Systems Interconnection model) is a conceptual framework used to understand and implement network protocols in seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Question 4: What is a protocol?
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A protocol is a set of rules and conventions that govern the communication between devices on a network. Examples include HTTP, TCP/IP, and FTP.

Question 5: What is an IP address?
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An IP address is a unique identifier assigned to each device connected to a network that uses the Internet Protocol for communication. It can be either IPv4 or IPv6.

Question 6: What is a MAC address?
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A MAC address (Media Access Control address) is a unique identifier assigned to a network interface card (NIC) for communication on the physical network segment.

Question 7: What is subnetting?
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Subnetting is the process of dividing a larger IP network into smaller, more manageable subnetworks (subnets) to improve network performance and security.

Question 8: What is the difference between TCP and UDP?
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TCP (Transmission Control Protocol) is connection-oriented, ensuring reliable data transfer, while UDP (User Datagram Protocol) is connectionless, providing faster but less reliable communication.

Question 9: What is DNS?
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DNS (Domain Name System) is a hierarchical system that translates human-readable domain names (e.g., www.example.com) into IP addresses that computers use to identify each other on the network.

Question 10: What is DHCP?
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DHCP (Dynamic Host Configuration Protocol) is a network management protocol used to automatically assign IP addresses and other network configuration parameters to devices on a network.

Question 11: What is a router?
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A router is a network device that forwards data packets between computer networks, directing the data along the most efficient paths.

Question 12: What is a switch?
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A switch is a network device that connects devices within a local area network (LAN) and uses MAC addresses to forward data to the correct destination.

Question 13: What is a firewall?
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A firewall is a network security device or software that monitors and controls incoming and outgoing network traffic based on predetermined security rules.

Question 14: What is NAT?
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NAT (Network Address Translation) is a method used by routers to translate private (local) IP addresses into a public IP address for communication over the internet.

Question 15: What is a VPN?
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A VPN (Virtual Private Network) is a secure connection method used to protect data transmitted over public networks by creating an encrypted tunnel between the user's device and the VPN server.

Question 16: What is a proxy server?
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A proxy server acts as an intermediary between a user's device and the internet, handling requests and forwarding them to the appropriate servers while masking the user's IP address.

Question 17: What is bandwidth?
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Bandwidth refers to the maximum rate at which data can be transferred over a network connection, typically measured in bits per second (bps).

Question 18: What is latency?
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Latency is the time it takes for data to travel from the source to the destination, often measured in milliseconds (ms). Lower latency means faster communication.

Question 19: What is packet switching?
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Packet switching is a method of data transmission where data is broken into small packets, each of which is sent independently over the network and reassembled at the destination.

Question 20: What is circuit switching?
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Circuit switching is a method of data transmission where a dedicated communication path is established between two endpoints for the duration of the connection, commonly used in traditional telephone networks.

Question 21: What is a VLAN?
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A VLAN (Virtual Local Area Network) is a logical grouping of devices on a network that allows them to communicate as if they were on the same physical LAN, even if they are not.

Question 22: What is a WAN?
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A WAN (Wide Area Network) is a network that spans a large geographic area, connecting multiple smaller networks, such as LANs, to enable communication over long distances.

Question 23: What is a LAN?
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A LAN (Local Area Network) is a network that connects devices within a limited geographic area, such as a home, office, or campus, allowing them to share resources and communicate.

Question 24: What is the difference between a hub and a switch?
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A hub broadcasts data to all devices on a network, while a switch forwards data only to the device for which it is intended, using MAC addresses to make forwarding decisions.

Question 25: What is a collision domain?
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A collision domain is a network segment where data packets can collide with each other when being sent over a shared medium, common in early Ethernet networks using hubs.

Question 26: What is a broadcast domain?
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A broadcast domain is a network segment where a broadcast sent from any device is received by all other devices within the same segment, typically limited by routers.

Question 27: What is QoS?
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QoS (Quality of Service) is a set of techniques used to manage network traffic and ensure the performance of critical applications by prioritizing certain types of data.

Question 28: What is a socket?
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A socket is an endpoint for communication between two devices on a network, defined by an IP address and a port number, used for sending and receiving data.

Question 29: What is a port number?
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A port number is a numerical identifier used to distinguish different services and applications on a networked device, allowing multiple connections to be managed simultaneously.

Question 30: What is SSL/TLS?
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SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are cryptographic protocols designed to provide secure communication over a network by encrypting data and ensuring its integrity and authenticity.

Question 31: What is HTTP/HTTPS?
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HTTP (Hypertext Transfer Protocol) is the protocol used for transmitting web pages over the internet. HTTPS (HTTP Secure) is an extension of HTTP that uses SSL/TLS to provide secure communication.

Question 32: What is FTP?
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FTP (File Transfer Protocol) is a standard network protocol used for transferring files between a client and a server on a computer network.

Question 33: What is a load balancer?
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A load balancer is a device or software that distributes incoming network traffic across multiple servers to ensure no single server becomes overwhelmed, improving performance and reliability.

Question 34: What is a multicast?
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Multicast is a communication method where data is transmitted from one sender to multiple receivers on a network simultaneously, using a special group address.

Question 35: What is unicast?
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Unicast is a communication method where data is sent from one sender to one receiver on a network, using the receiver's unique IP address.

Question 36: What is broadcast?
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Broadcast is a communication method where data is sent from one sender to all devices on a network segment, using a special broadcast address.

Question 37: What is an access point?
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An access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, providing network access within a specific area.

Question 38: What is a SSID?
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SSID (Service Set Identifier) is the name assigned to a Wi-Fi network, allowing users to identify and connect to the correct wireless network.

Question 39: What is network topology?
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Network topology refers to the arrangement of elements (links, nodes, etc.) in a computer network. Common topologies include star, bus, ring, mesh, and hybrid.

Question 40: What is a star topology?
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In a star topology, all network devices are connected to a central hub or switch, with each device having a dedicated connection to the central point.

Question 41: What is a mesh topology?
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In a mesh topology, devices are interconnected, with each device connected to multiple other devices, providing high redundancy and reliability.

Question 42: What is a bus topology?
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In a bus topology, all devices share a common communication line or bus, with data transmitted in both directions along the bus.

Question 43: What is a ring topology?
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In a ring topology, devices are connected in a circular fashion, with each device having exactly two neighbors for communication purposes.

Question 44: What is an IPsec?
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IPsec (Internet Protocol Security) is a suite of protocols used to secure Internet Protocol (IP) communications by authenticating and encrypting each IP packet in a communication session.

Question 45: What is MPLS?
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MPLS (Multiprotocol Label Switching) is a data-carrying technique for high-performance telecommunications networks that directs data from one node to the next based on short path labels rather than long network addresses.

Question 46: What is a BGP?
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BGP (Border Gateway Protocol) is a standardized exterior gateway protocol used to exchange routing information between different networks on the internet.

Question 47: What is OSPF?
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OSPF (Open Shortest Path First) is an interior gateway protocol used for routing IP packets within a single routing domain, using a link-state routing algorithm.

Question 48: What is an ARP?
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ARP (Address Resolution Protocol) is a protocol used to map an IP address to a MAC address, enabling communication on a local network.

Question 49: What is RARP?
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RARP (Reverse Address Resolution Protocol) is a protocol used by a device to request its IP address from a network server when it only has its MAC address.

Question 50: What is ICMP?
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ICMP (Internet Control Message Protocol) is a protocol used for network diagnostics and error reporting, often used by tools like ping and traceroute.

Question 51: What is a CSU/DSU?
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A CSU/DSU (Channel Service Unit/Data Service Unit) is a device used to connect a digital data line to a router or other network device, converting signals for transmission over the network.

Question 52: What is the three-way handshake?
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The three-way handshake is a process used in TCP/IP networks to establish a connection between a client and a server. It involves three steps: SYN, SYN-ACK, and ACK.

Question 53: What is a ping?
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Ping is a network utility used to test the reachability of a host on an IP network and measure the round-trip time for messages sent from the originating host to a destination computer.

Question 54: What is traceroute?
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Traceroute is a network diagnostic tool used to track the path packets take from one IP address to another, displaying each hop along the way.

Question 55: What is an intrusion detection system (IDS)?
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An IDS (Intrusion Detection System) is a device or software application that monitors network traffic for suspicious activity and potential threats, alerting administrators to possible security breaches.

Question 56: What is an intrusion prevention system (IPS)?
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An IPS (Intrusion Prevention System) is a network security device that monitors network traffic for malicious activities and takes preventive actions, such as blocking traffic, to protect the network.

Question 57: What is a honeypot?
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A honeypot is a security mechanism set up to detect, deflect, or study attempts at unauthorized access to information systems, by creating a decoy system that appears legitimate.

Question 58: What is BYOD?
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BYOD (Bring Your Own Device) is a policy that allows employees to use their personal devices, such as smartphones and laptops, for work purposes, accessing the company's network and data.

Question 59: What is cloud computing?
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Cloud computing is the delivery of computing services, including storage, processing, and networking, over the internet (the cloud), allowing users to access and use resources on demand.

Question 60: What is SDN?
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SDN (Software-Defined Networking) is an approach to network management that enables dynamic, programmatically efficient network configuration to improve network performance and monitoring.

Question 61: What is CDN?
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A CDN (Content Delivery Network) is a distributed network of servers that delivers web content and services to users based on their geographic location, improving load times and reliability.

Question 62: What is load balancing?
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Load balancing is the process of distributing network traffic across multiple servers to ensure no single server is overwhelmed, improving application performance and reliability.

Question 63: What is network latency?
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Network latency is the time it takes for a data packet to travel from the source to the destination, often measured in milliseconds (ms). Lower latency means faster communication.

Question 64: What is a network administrator?
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A network administrator is responsible for maintaining computer networks, ensuring they run efficiently and securely, and troubleshooting any issues that arise.

Question 65: What is network redundancy?
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Network redundancy is the inclusion of extra or duplicate network devices, paths, or connections to ensure network availability and reliability in case of failure.