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11 Common Network Interview Questions

Guest Author: Jessica

The network engineer role has become a staple in companies across all types of industries. The modern enterprise needs to maintain as many 9s of uptime for people, systems, and resources as possible. Considering the critical role of networks, it's necessary that candidates prepare adequately for the network interview. This article will introduce you to the most common (but tricky) interview questions any network engineer should be able to answer confidently.

The first thing to know is that different companies have different protocols, processes, techniques, and questions for networks engineer interviews. Besides technical questions, you need to expect behavioral and cultural questions, which are sometimes available in two parts. Rehearsing your questions ahead of time will enable you to quickly determine if you actually know the correct answer to a tricky question. If it happens that you don't - as is often the case - be transparent about it. Employers are aware that you're not a walking encyclopedia, so don't be ashamed if you don't know. If you're open enough, it makes it easier for them to see your approach to handling unfamiliar issues. When you show up to interview for a network interview role, there are a few questions that you'll do well to prepare for. Here are a few of such qualitative questions with suggestions on how you can reason through your answers.

#1 - "What's a link?"

Some interviews will begin with the LAN or Local Area Network. This refers to the connection between computers and other network devices located within a small physical location. Providing a definition for "LAN" invariably leads the interviewer to ask about links. A link is nothing more than the connectivity between two devices. What connects those devices are the cables and protocols on a device that enable it to communicate with another one. Networks usually involve distinct devices or systems called nodes, so if you're asked about them, you may talk about how they refer to a point or joint where a connection exists. You need at least two nodes to form a network connection. But, networks do not exist in isolation. There is a stream of information passed between two or more network segments, and these require routers to connect them. What are routers? These are intelligent network devices that store information in routing tables such as bottlenecks, hops, and paths. This information helps a network engineer to determine the best path to transfer data. Also mention that routers operate at the OSI Network Layer. The interview could then evolve naturally to have you list out the 7 layers of the OSI reference model and talking about the backbone network. The seven layers include the physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer. The backbone network refers to a centralized infrastructure designed to distribute different routes and data to networks. It's also responsible for managing bandwidth and multiple channels. There are different ways to connect computers on a network. One of these is a point-to-point link, a direct connection that requires no other network devices rather than a cable linking the respective NIC (Network Interface Cards) cards of the computers.

#2 - "What is Anonymous FTP?"

Any professional conversation about networks will include talk about protocols, so a simple answer is that anonymous FTP is a way to grant user access to files in public servers. You need to explain that users do not need to identify themselves on anonymous FTP servers; they only need to log in as an anonymous guest.

#3 - "What are Subnet Masks?"

Subnet masks are used in combination with an IP address to identify two parts including the host address and extended network address. A subnet mask consists of 32 bits, just like an IP mask. Your interviewer could then proceed to ask you about the largest network you've ever deployed or engineered. This question requires a logical outline of how you achieved this. A good approach to answering this question and others like it is to use the STAR method - Situation, Task, Action, and Result. This framework helps you to thoroughly describe the issue and how you tackled it.

#4 - "Have you led a network team or worked on one?"

Interviewers at large enterprises usually want to know if you've worked on a team tasked with deploying network resources or led one. Depending on the situation, a network engineer will likely lead a team of network administrators or engineers. As much as it's rarely indicated in the job description, you'll likely work with other IT professionals to implement large projects.

#5 - "Briefly describe data encapsulation and what it achieves?"

Data is what goes back and forth on a network, so one possible question could be on how networks manage bits of information for efficient transmission. The answer lies in data encapsulation, the process of splitting information into more manageable chunks small enough to travel speedily across the network. In this process, the headers hold the source and destination addresses along with parity checks.

#6 - "How would you go about network security in a mid-sized enterprise?"

In many cases, network interviews involve testing your mindset for end-to-end security. Discuss what you did elsewhere to ensure network security, detailing how you handled previous breaches (another great place to use the STAR method) and why end-to-end security is crucial to keep networks protected. This is what your interviewer wants to know when they ask about your stance on network security and your security procedure.

#7 - "What steps would you take to scale our network if we suddenly grew 2x?"

If you have any experience on network projects, your prospective employer will care to know how you would go about scaling networks. A step-by-step logical answer works well here too. Highlighting examples from previous jobs will strengthen your case to land the job, especially if you can point out the factors that influenced your decisions.

#8 - "Could you lay out a concise network topology for me?"

It's okay to practice drawing network topologies beforehand because you just might hear your interviewer ask you to deliver one on the spot. Your design needs to be tidy and comprehensive design that reflect the size, network type, organization, and specific elements critical to optimal implementation of the network. Your design should be intuitive and easy to explain to even non-technical people. Network topology itself deals with the layout of a computer network. How the devices and cables are laid out and how are they connected is the scope of network topology.

#9 - "Why does your network topology matter?"

Your network topology matters because it determines the media you need to interconnect devices. Using network topologies, you define applicable connectors, materials, and terminations for a particular setup.

#10 - "What's a VPN?"

Virtual Private Networks are technologies that enable users to create a secure tunnel across a network. Many organizations use VPNs to establish a dial-up connection to remote servers. Earlier, we introduced networks, and in many companies, and you might find your interviewer talking about NATs once you get in gear discussing VPNs. NAT is an acronym for Network Address Translation, is a protocol that allows several computers on a network to share one internet connection.

#11 - "What do you do when you troubleshoot a network?

Networks typically experience issues, and your interviewer is explicitly checking out your troubleshooting process with this question. You need to own your own logical process for solving problems when they arise. This analytical methodology should be quick, thorough, and involve a standard set of resources that you use to achieve this.


These are some of the most recurring Network Interview Questions with answers that will impress any interviewer. Answering these network interview questions with clarity will position you better than the majority of candidates who have only learned the concepts by rote. Network concepts are only straightforward to those who've studied them thoroughly. Thankfully, this guide shows you some of what interviewers really care about.