Networking is one of the most crucial areas in IT, and interviewers often test both theoretical understanding and practical knowledge of how networks function. Below is a complete list of general, intermediate, and advanced networking interview questions with their answers to help you prepare effectively.

General Networking Interview Questions 

1. Name two technologies to interconnect two offices in different locations.

There are different technologies for connecting two offices located in the world, namely VPN and Cloud Networking.

2. What is internetworking?

Internetworking refers to the interconnection of different networks or systems through devices like routers or gateways. It is the process of connecting networks that are separated from each other into one large connected network, with the ability to integrate public, private, or corporate infrastructures. The purpose of creating different networks is only to make them work as a whole—one system.

3. What are the software layers (user support layers) in the OSI model?

Software layers in the OSI model are the following:

• Application Layer

• Presentation Layer

• Session Layer

4. What are the hardware layers (network support layers) in the OSI model?

The hardware layers are:

• Network Layer

• Data Link Layer

• Physical Layer

5. What is the HTTPS protocol?

HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP. HTTPS enables secure browsing using encrypted communication. This protocol works on port 443 with the help of SSL/TLS for data encryption.

6. Name some of the services in the Internet application layer.

Just as the network does, so does the application provide:

• Email Services

• Directory Services

• File Transfer

• Access Control

• Network Virtual Terminal

7. Where in the OSI layer are the header and trailer added?

• Trailer: Data Link Layer

• Header: 6 (Presentation Layer), 5 (Session Layer), 4 (Transport Layer), and 3 (Network Layer)

8. What happens to a data packet as it goes from lower to upper layers of the OSI hierarchy?

As the packet climbs up the layers, it will be stripped of headers at every layer.

9. What happens to the data packet when it passes to the lower layers through the upper layers of the OSI model?

When it goes down the layers, the packet gets the headers that are applied with its important routing and control information.

10. What is a zone-based firewall?

The zone-based firewall is a type of stateful firewall that filters traffic according to zone (internal, external, DMZ). It tracks connection states and contexts, allowing ingress traffic only upon an inside request. Zone-Based Policy Firewall (ZPF) technology is used in Cisco routers to implement this type of firewall.

11. What is a VPN?

VPN stands for Virtual Private Network, which means that this technology creates a tunnel that is secure, encrypted tunnel across a less secure network—like the Internet—so that remote users or offices can safely connect to a private network. For secrecy and integrity, it uses tunneling protocols to protect the data.

Intermediate Networking Interview Questions

12. What’s IP Spoofing?

IP Spoofing is the sending of IP packets from what appears to be an address other than its source address, generally misleading the recipient into thinking it is a valid address, often used in denial-of-service (DoS) attacks. Masking the origin of the attack or enabling unauthorized access is normally the ultimate goal in such cases.

13. What do “threat,” “vulnerability,” and “risk” signify regarding networking security?

• Threat: Any person or thing capable of exploiting a particular vulnerability with the intent to cause damage to an asset (data, system, or people).

• Vulnerability: A flaw exists in a system, and in some cases has the possibility to be exploited by a threat.

• Risk: The possibility of loss or damage to assets caused when the threat successfully exploits a vulnerability.
  Formula: Risk = Threat + Vulnerability + Asset

14. What is its main job as a DNS server?

The DNS (or Domain Name System) server translates human-readable addresses into numerical addresses so that it can access websites by name instead of numerical IPs. Traffic across the Internet can be routed based on this mapping of domain names to IP addresses.

15. Which protocol does DNS use, and the port number is associated with it?

DNS runs on UDP/TCP port number 53.

16. Where do transmission media fit into the OSI model?

Transmission media like cables and wireless are in layer 1 of the OSI model—the physical layer.

17. Why are twists important in twisted pair cable?

Twisted pair cables offer the advantage of twisting to reduce environmental interference and crosstalk between wires, allowing for clean signals and low data errors.

18. What type of multiple errors cannot be detected by Checksum?

Checksums usually do not detect multiple-bit errors; rather, they handle a simple error, such as a single-bit error.

19. What multiplexing applies to fiber optic links?

Wavelength Division Multiplexing (WDM) is how fiber-optic communications multiplexes many signals over different wavelengths of light for extremely high application bandwidth.

Advanced Networking Interview Questions

20. What are the advantages and disadvantages of piggybacking?

• Advantages: Increase efficiency of use of bandwidth through the combination of a data frame with an acknowledgment frame.

• Disadvantages: It complexifies the system and causes unnecessary retransmissions if no acknowledgment is generated within a certain period of time.

21. Which multiplexing technique is deployed in byte-oriented protocols?

Byte stuffing is a type of multiplexing technique used in byte-oriented protocols. It inserts special characters into the data stream to avoid confusion with frame delimiters or control characters.

22. What is Orthogonal Frequency Division Multiplexing (OFDM)?

OFDM is a technique for transmitting data in such a way that the data is split into as many sub-channels as necessary, which are transmitted in parallel at different frequencies. OFDM is very efficient and used in today's modern broadband communication systems, such as Wi-Fi and LTE.

23. What is a transparent bridge?

A transparent bridge learns the net addresses and filters the traffic based on that knowledge. It forwards frames between networks and acts in such a way as to reduce collisions. Such a device is "transparent," in that no changes are needed on connected devices.

24. What is the minimum and maximum size of an ICMPv4 packet?

• Minimum size: 28 bytes

• Maximum size: 2068 bytes

25. Why is OSPF faster than RIP?

OSPF (Open Shortest Path First) is faster than RIP (Routing Information Protocol) because it employs a link-state algorithm, which allows it to quickly respond and calculate the shortest paths using the Dijkstra algorithm. The OSPF also offers classless routing with variable-length subnet masks.

26. What are the two general types of DNS messages?

DNS messages are classified as queries or requests for information and replies, responses returned to requests.

27. What is POP3 in email?

POP3 (Post Office Protocol version 3) allows email clients to download messages from a server to the local machine. This helps because a user can access emails offline once they are downloaded, making it suitable for users needing to read their emails without being online.

28. What is the difference between TCP and UDP?

TCP refers to Transmission Control Protocol, which is a connection-oriented protocol intended to guarantee reliable data transmission with error checking, flow control, and acknowledgment. UDP stands for User Datagram Protocol, which is a connectionless protocol delivering messages from one computer to another without routing devices regulating the transmission process.

29. What is a NAT?

NAT, in actual use, translates all those little IP addresses in some private network inside into a single public-facing IP address. This would allow multiple devices in the private network to gain access to the outside world through the Internet using a single IP address, with which the outside world would do all its communicating.

30. What does a load balancer do in a network?

A load balancer distributes incoming network traffic onto many servers to ensure that no single server is swamped while its system remains highly available and responsive. It enables great improvement in performance, redundancy, and scalability.

Conclusion

Networking fundamentals and advanced concepts are essential for anyone pursuing a career in IT infrastructure, system administration, or cybersecurity. Reviewing these questions will help you strengthen your understanding and confidently face technical interviews that test your networking knowledge.

Computer networking plays a foundational role, enabling devices to communicate, share resources, and support critical business operations. Networking connects not just systems but people, driving innovation and data exchange across industries. As one source notes, networking is “a crucial part of modern computing, allowing global communication and resource sharing that support nearly every business function.”

If you are looking to build a strong foundation in networking or prepare for certifications like CCNA, CCNP, or cybersecurity programs, Network Kings is a well-known online training platform offering live and self-paced courses guided by industry experts. Based in India, Network Kings provides hands-on labs, certification training, and career-oriented programs across networking, cloud, and cybersecurity domains. Their real-time practical training approach helps learners gain the skills required to excel in networking careers.