Computer Networks Interview Q&A

Q&A Top 50 in Computer Network

1. What is a computer network?

A computer network is a collection of interconnected devices (computers, servers, routers) that can share data and resources.

2. What is a LAN?

LAN stands for Local Area Network, which connects devices within a limited geographical area, such as an office or home.

3. What is a WAN?

WAN stands for Wide Area Network, which connects devices over a large geographical area, typically using public networks.

4. What is the OSI model?

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes network communication into seven layers.

5. What is TCP/IP?

TCP/IP is a set of protocols used to enable communication on the internet and most computer networks.

6. What is IP address?

An IP address is a unique numerical label assigned to each device on a network, enabling them to be identified.

7. What is subnetting?

Subnetting is dividing a large network into smaller subnetworks for efficient IP address allocation.

8. What is DHCP?

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses to devices on a network.

9. What is DNS?

DNS (Domain Name System) translates human-readable domain names into IP addresses.

10. What is ARP?

ARP (Address Resolution Protocol) resolves IP addresses to MAC addresses on a local network.

11. What is a router?

A router is a networking device that forwards data packets between different networks.

12. What is a switch?

A switch is a networking device that connects devices within a local network and forwards data between them.

13. What is a gateway?

A gateway is a device that connects different network types, enabling communication between them.

14. What is bandwidth?

Bandwidth is the maximum data transfer rate of a network or internet connection.

15. What is latency?

Latency is the delay in data transmission between two points on a network.

16. What is a firewall?

A firewall is a security device that filters and controls incoming and outgoing network traffic.

17. What is NAT?

NAT (Network Address Translation) converts private IP addresses to public IP addresses for internet communication.

18. What is VPN?

VPN (Virtual Private Network) creates a secure encrypted connection over a public network, ensuring privacy.

19. What is a proxy server?

A proxy server acts as an intermediary between clients and the internet, enhancing security and performance.

20. What is a MAC address?

A MAC address is a unique identifier assigned to each network interface card (NIC).

21. What is ICMP?

ICMP (Internet Control Message Protocol) handles error messages and network diagnostics.

22. What is a broadcast address?

A broadcast address is used to send data to all devices on a network.

23. What is a subnet mask?

A subnet mask identifies the network and host portions of an IP address.

24. What is the difference between TCP and UDP?

TCP (Transmission Control Protocol) is connection-oriented and ensures reliable data delivery, while UDP (User Datagram Protocol) is connectionless and faster but may not guarantee delivery.

25. What is port number?

A port number identifies specific processes or services on a device within a network.

26. What is a MAC flooding attack?

A MAC flooding attack overloads the switch’s MAC address table, causing it to act like a hub, making data visible to all devices.

27. What is a man-in-the-middle attack?

A man-in-the-middle attack intercepts communication between two parties to eavesdrop or manipulate data.

28. What is a denial-of-service (DoS) attack?

A DoS attack floods a network or service with excessive traffic, causing it to become unavailable.

29. What is VLAN?

VLAN (Virtual LAN) logically segments a physical LAN into multiple virtual LANs for security and traffic management.

30. What is STP?

STP (Spanning Tree Protocol) prevents network loops in redundant switch connections.

31. What is QoS?

QoS (Quality of Service) prioritizes network traffic to ensure specific data types receive better service.

32. What is the difference between half-duplex and full-duplex?

In half-duplex, data can be transmitted or received, but not simultaneously, whereas in full-duplex, data can be transmitted and received simultaneously.

33. What is PoE?

PoE (Power over Ethernet) delivers power to network devices over the Ethernet cable.

34. What is the purpose of traceroute?

Traceroute is used to identify the path and latency of data packets between two points on a network.

35. What is a DMZ?

DMZ (Demilitarized Zone) is a separate network that provides an additional layer of security between the internet and an internal network.

36. What is network congestion?

Network congestion occurs when the network experiences heavy traffic, leading to reduced performance.

37. What is a packet?

A packet is a unit of data transmitted over a network.

38. What is a collision domain?

A collision domain is a network segment where data collisions can occur on shared media, like in Ethernet hubs.

39. What is CSMA/CD?

CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is an Ethernet protocol to detect and resolve data collisions.

40. What is IEEE 802.11?

IEEE 802.11 is a standard for wireless LAN technology (Wi-Fi).

41. What is a MAC filtering?

MAC filtering restricts network access based on MAC addresses.

42. What is a network topology?

Network topology defines the physical or logical layout of devices and their connections in a network.

43. What is the purpose of a subnet?

Subnets help divide a large network into smaller segments for easier management and improved security.

44. What is SDN?

SDN (Software-Defined Networking) separates the control plane and data plane, enabling centralized network management.

45. What is a network protocol?

A network protocol is a set of rules defining how devices communicate and exchange data on a network.

46. What is ARP poisoning?

ARP poisoning (spoofing) is a cyber attack that alters ARP tables to redirect traffic to a malicious device.

47. What is network virtualization?

Network virtualization enables the creation of virtual networks using software-based techniques.

48. What is multiplexing?

Multiplexing combines multiple data streams into a single channel for more efficient data transmission.

49. What is a gateway router?

A gateway router connects networks with different protocols, enabling communication between them.

50. What is the purpose of ICMP Echo Request and Reply?

ICMP Echo Request (ping) sends a packet to check if a host is reachable, and ICMP Echo Reply responds if the host is available.