Core Subjects
Computer Networks Questions A comprehensive collection of Computer Networking interview questions covering basics, OSI layers, protocols, and IP addressing. Perfect for technical screenings.
1. What is Computer Networking? Beginner 2. What is the difference between Hub, Switch, and Router? Intermediate 3. What is the difference between TCP and UDP? Intermediate 4. What is IP Address? Explain IPv4 and IPv6. Beginner 5. What is MAC Address? How is it different from IP Address? Intermediate 6. What is the difference between Public and Private IP Address? Intermediate 7. What is a Port Number? Give examples of common ports. Beginner 8. What is DNS and how does it work? Intermediate 9. What is DHCP? How does it assign IP addresses? Intermediate 10. What is the difference between HTTP and HTTPS? Beginner 11. What is Gateway? Beginner 12. What is Subnet Mask? Intermediate 13. What is NAT (Network Address Translation)? Advanced 14. What is localhost and 127.0.0.1? Beginner 15. What is Bandwidth and Latency? Beginner 16. What is the OSI Model? Name all 7 layers. Beginner 17. What is the difference between OSI and TCP/IP Model? Intermediate 18. What happens at each layer of OSI Model? Intermediate 19. Which layer is responsible for routing? Beginner 20. Which layer is responsible for error detection? Intermediate 21. What is the function of Transport Layer? Intermediate 22. What is the function of Network Layer? Intermediate 23. What is the function of Data Link Layer? Intermediate 24. What is Encapsulation and Decapsulation? Advanced 25. What is PDU (Protocol Data Unit)? Intermediate 26. Which protocols work at which OSI layer? Advanced 27. What is the difference between Layer 2 and Layer 3 Switch? Advanced 28. What is the Application Layer responsible for? Beginner 29. Why do we need a layered network model? Intermediate 30. What is the Session Layer used for? Intermediate 31. Explain TCP 3-Way Handshake in detail. Intermediate 32. What is SYN, SYN-ACK, and ACK? Intermediate 33. How is TCP connection terminated? (4-Way Handshake) Advanced 34. What is the difference between Connection-Oriented and Connectionless Protocol? Intermediate 35. Why does DNS use UDP instead of TCP? Advanced 36. What is ARP (Address Resolution Protocol)? Intermediate 37. What is ICMP? What does ping use? Intermediate 38. What is the difference between FTP and SFTP? Beginner 39. What is SMTP, POP3, and IMAP? Beginner 40. What is SSH and which port does it use? Beginner 41. What is Telnet? Why is SSH preferred over Telnet? Beginner 42. What is HTTP methods (GET, POST, PUT, DELETE)? Intermediate 43. What is HTTP Status Codes? (200, 404, 500, etc.) Beginner 44. What is SSL/TLS? How does HTTPS work? Advanced 45. What is a Socket? Intermediate 46. What are IP Address Classes (A, B, C, D, E)? Intermediate 47. What is Subnetting and why is it needed? Intermediate 48. How do you calculate Subnet Mask? Advanced 49. What is CIDR notation? Intermediate 50. What are the private IP address ranges? Beginner 51. What is the difference between Static and Dynamic IP? Beginner 52. What is APIPA (Automatic Private IP Addressing)? Intermediate 53. What is Loopback Address? Beginner 54. What is Broadcast Address? Intermediate 55. What is Network Address? Intermediate 56. What is the difference between IPv4 and IPv6? Intermediate 57. Why do we need IPv6? Beginner 58. What is the size of IPv4 and IPv6 addresses? Beginner 59. How many hosts can a /24 network have? Intermediate 60. What is Supernetting? Advanced 61. What is Routing? Beginner 62. What is a Routing Table? Intermediate 63. What is the difference between Static and Dynamic Routing? Intermediate 64. What is Default Gateway? Beginner 65. What are Routing Protocols? Name a few. Intermediate 66. What is RIP, OSPF, and BGP? Advanced 67. What is the difference between Distance Vector and Link State Routing? Advanced 68. What is Hop Count? Beginner 69. What is TTL (Time To Live)? Intermediate 70. What is the difference between Router and Switch? Beginner 71. What is VLAN? Why is it used? Intermediate 72. What is Spanning Tree Protocol (STP)? Advanced 73. What is the difference between Circuit Switching and Packet Switching? Intermediate 74. What is a Virtual Circuit? Advanced 75. What is the difference between Layer 2 and Layer 3 devices? Intermediate 76. What is Firewall? What are its types? Beginner 77. What is the difference between Stateful and Stateless Firewall? Advanced 78. What is VPN and how does it work? Intermediate 79. What is Encryption? Explain Symmetric and Asymmetric Encryption. Intermediate 80. What is the difference between Encryption and Hashing? Advanced 81. What is SSL Certificate? Beginner 82. What is DoS and DDoS attack? Beginner 83. What is the difference between DoS and DDoS? Intermediate 84. How to prevent DDoS attacks? Intermediate 85. What is Man-in-the-Middle (MITM) Attack? Advanced 86. What is DNS Spoofing? Advanced 87. What is Phishing? Beginner 88. What is the difference between Virus, Worm, and Trojan? Intermediate 89. What is SQL Injection? Advanced 90. What is a Brute Force Attack? Beginner 91. How does a packet travel from source to destination? (End-to-End) Advanced 92. What happens when you type www.google.com in your browser? Intermediate 93. What is Load Balancer? What are Load Balancing algorithms? Advanced 94. What is the difference between Load Balancer and Reverse Proxy? Advanced 95. What is CDN (Content Delivery Network)? Intermediate 96. What is the difference between Horizontal and Vertical Scaling? Intermediate 97. What is Caching? What are different types of caching? Intermediate 98. Explain ping, traceroute, and netstat commands. Beginner 99. What is the difference between Unicast, Broadcast, and Multicast? Intermediate 100. What is the difference between LAN, MAN, and WAN? Beginner