What is port forwarding and when is it used?

Heisenbug logo
TheHeisenBug

Search

Search across questions, learning content, and hands-on projects

Ace Your Next Tech Interview

5,986+ interview questions across 87 technologies — with expert answers, advanced search, AI-powered assistance, personal highlights, structured learning paths, and hands-on practice projects.

5,986+Questions & Answers
87Technologies
AdvancedSearch
Built-inAsk AI
PersonalHighlights
StructuredLearning Paths
Hands-onPractice Projects

Lifetime Access

One-time payment. No subscriptions. Unlock everything, forever.

$19.90USD

or R$49.90 BRL

FeatureFreePremium
Question titlesAllAll
Answers per topicTop 5All
Learning chaptersFirst 5All
Practice projectsFirst 3All
Highlights✓✓
Ask AI—✓
Read tracking✓✓
Search✓✓

Networking Fundamentals Interview Questions

  1. [JUNIOR] What is the OSI model and what are its seven layers?
  2. [JUNIOR] What is the difference between TCP and UDP?
  3. [JUNIOR] What is a computer network and what are its main purposes?
  4. [JUNIOR] What is an IP address and what is its purpose?
  5. [JUNIOR] What is the difference between a router and a switch?
  6. [JUNIOR] What is DNS and what is its purpose?
  7. [MID] What happens when you type a URL into a web browser and press Enter?
  8. [MID] How does the TCP three-way handshake work?
  9. [JUNIOR] What are the different types of networks (LAN, WAN, MAN) and how do they differ?
  10. [JUNIOR] What is the difference between IPv4 and IPv6?
  11. [JUNIOR] What is a MAC address and how does it relate to a network interface card (NIC)?
  12. [JUNIOR] What is DHCP and why is it used?
  13. [JUNIOR] What is a subnet and what is a subnet mask?
  14. [JUNIOR] What is a firewall and what are its basic types?
  15. [JUNIOR] What is HTTP and how does HTTPS differ from it?
  16. [MID] What is ARP and how does it resolve IP addresses to MAC addresses?
  17. [MID] What is NAT (Network Address Translation) and why is it needed?
  18. [MID] What is the TCP/IP model and how does it differ from the OSI model?
  19. [MID] How does subnetting work and what is CIDR notation?
  20. [MID] How does DNS resolution work step by step, including recursive and iterative queries?
  21. [JUNIOR] What are public and private IP addresses?
  22. [JUNIOR] What is a default gateway?
  23. [JUNIOR] What is a VPN and how does it work?
  24. [JUNIOR] What is network latency and how is it measured?
  25. [JUNIOR] What is the purpose of a port number in networking?
  26. [JUNIOR] What is the difference between unicast, multicast, and broadcast?
  27. [MID] What is ICMP and what role does it play in networking?
  28. [MID] What is a VLAN and why is it used?
  29. [MID] What is a proxy server and how does it differ from a reverse proxy?
  30. [MID] What is a socket in networking and how is it used for communication?
  31. [MID] What are the differences between TCP flow control and congestion control?
  32. [MID] How does the TCP sliding window mechanism work?
  33. [SENIOR] What is BGP (Border Gateway Protocol) and how does it prevent routing loops?
  34. [SENIOR] How would you design a highly available network architecture with redundancy and failover?
  35. [SENIOR] How does a DDoS attack work and what are the mitigation strategies?
  36. [JUNIOR] What are the different types of network topologies?
  37. [JUNIOR] What is bandwidth in networking?
  38. [JUNIOR] What is a ping command and what is it used for?
  39. [MID] What is the difference between static and dynamic routing?
  40. [MID] What are collision domains and broadcast domains and how do they differ?
  41. [MID] What is the TTL (Time to Live) field in an IP packet and why is it important?
  42. [MID] How does traceroute work and how does it help diagnose network issues?
  43. [MID] What is the difference between symmetric and asymmetric encryption in network security?
  44. [SENIOR] What is OSPF (Open Shortest Path First) and how does it differ from RIP?
  45. [SENIOR] What is STP (Spanning Tree Protocol) and why is it needed to prevent network loops?
  46. [SENIOR] How does IPsec work and what protocols does it use to secure network traffic?
  47. [SENIOR] What are the different types of NAT (Static, Dynamic, PAT) and when would you use each?
  48. [EXPERT] How does a zero-trust security model apply to network architecture?
  49. [JUNIOR] What is the difference between half-duplex and full-duplex communication?
  50. [MID] What is the difference between a layer 2 switch and a layer 3 switch?
  51. [MID] What is MTU (Maximum Transmission Unit) and how can MTU-related issues affect network performance?
  52. [MID] What is QoS (Quality of Service) and why is it important in networking?
  53. [MID] What is a DMZ (Demilitarized Zone) in network architecture?
  54. [MID] What are ACLs (Access Control Lists) and how are they used in networking?
  55. [SENIOR] What is MPLS (Multiprotocol Label Switching) and what are its use cases?
  56. [SENIOR] What is SDN (Software-Defined Networking) and how does it differ from traditional networking?
  57. [SENIOR] What is the difference between VLAN and VXLAN?
  58. [SENIOR] How does NAT traversal work and what challenges does it present for peer-to-peer communication?
  59. [SENIOR] What is a broadcast storm and how do you prevent it?
  60. [SENIOR] What is the difference between IDS (Intrusion Detection System) and IPS (Intrusion Prevention System)?
  61. [SENIOR] What is network automation and what tools and protocols enable it?
  62. [EXPERT] How do you diagnose and resolve TCP retransmission issues in a production environment?
  63. [EXPERT] How would you design a network architecture that supports IPv4 to IPv6 transition using dual-stack, tunneling, and translation?
  64. [EXPERT] How do you troubleshoot intermittent packet loss across multiple network hops in a production system?
  65. [EXPERT] How would you design a multi-region cloud network architecture with low-latency and high-availability requirements?
  66. [MID] What is port forwarding and when is it used?
  67. [MID] What are ephemeral ports and how are they used in TCP/UDP connections?
  68. [SENIOR] What are overlay networks and when would you use them?
  69. [SENIOR] What is link aggregation and how does LACP (Link Aggregation Control Protocol) work?
  70. [SENIOR] What is DHCP snooping and how does it improve network security?
  71. [SENIOR] How does EIGRP differ from OSPF in terms of algorithm and convergence?
  72. [SENIOR] What are route reflectors in BGP and why are they needed at scale?
  73. [EXPERT] What is BGP route hijacking and how can it be detected and prevented?
  74. [EXPERT] How does Anycast routing work and what are its benefits and challenges at scale?
  75. [EXPERT] What is the role of eBPF in modern network observability and security?
  76. [SENIOR] What is GRE (Generic Routing Encapsulation) tunneling and when would you use it?
  77. [EXPERT] How does segment routing differ from traditional MPLS and what advantages does it offer?
  78. [EXPERT] What is OpenFlow in SDN and how does it enable programmable network control?
  79. [EXPERT] How does MPLS Traffic Engineering work and when is it used?
  80. [EXPERT] What are the trade-offs between hardware-based and software-based network functions at scale?