Top 10 Network Engineer Interview Questions

Network engineers are integral to the functioning of any large organization that relies on computers–which is to say, nearly all of them. This means that network engineer interview questions can be difficult. Employers want to hire the best of the best, and tough interview questions are a great way to eliminate weak candidates.

In such a competitive field, just being great at your work isn’t enough. You need to ace the interview if you want a successful career. To help you get ready for your interview, this article will offer example answers for some of the most common network engineer interview questions.

What is a network engineer?

Put simply, network engineers design, build, and maintain computer networks. A computer network is a collection of computers that are connected to each other and share data. They can be physically connected through wires, or connected remotely through the internet. Any large organization with its own computer network will require network engineers, making network engineering a good career choice for people entering the tech field.

Network engineers must be experts in computer networking hardware, like modems, routers, switches, hubs, cables, servers, and more. The specific hardware will depend on the network architecture, so as a network engineer you may be working with all, some, or none of this hardware.

Network software is software used to run a computer network. This software can include tools for designing, monitoring, troubleshooting, or facilitating networks. Network engineers use software to manage users, store and transfer files, operate security systems, and more.

Network Engineer Interview Questions

Even if you’re an expert in your field, it’s important to prepare answers for a job interview. Coming up with good responses can be difficult when you’re on the spot. To get ready for your interview, study these network engineer interview questions.

1. Why do you want to be a network engineer?

I’ve always been interested in computers. Even as a kid, I would spend hours trying to understand how the family computer worked and how different computers could communicate with each other. Throughout high school and college, I was able to take classes to learn more about information technology and how computers communicate, and I became very skilled at getting networks up and running. I still love learning about new technologies, so a career as a network engineer is a perfect fit for me.

2. What is FTP?

FTP stands for File Transfer Protocol. FTP is a communication protocol that can be used to send data from a server to a client using a computer network. Essentially, it is a way to move files online. FTP is an old protocol that is not used very often anymore, but some organizations use it to move large files within a closed network when security isn’t a concern.

3. What is the difference between LAN and WAN?

LAN stands for Local Area Network. A LAN is a collection of connected computers and other devices in a relatively small location, usually a single building. For example, a single LAN might be based in a school, office, or home. It might connect several computers in a computer lab, or simply connect your home laptop to a printer.

WAN stands for Wide Area Network. A WAN connects computers that are distributed across a large area, like a city or state. A WAN is usually used by a single large organization with multiple locations. For example, a WAN might be used to connect devices across a company’s different regional offices, or a university’s satellite campuses. WANs are larger and more complex than LANs, and may contain different LANs connected by long-distance network infrastructure.

4. What steps would you take to troubleshoot a local network?

If a network is producing errors, or a user is having difficulty connecting to the network, I like to start by testing hardware. In a network with wires, the cables themselves are a likely point of failure. The exact process to check on the hardware will depend on the network. Copper wiring, fiber optic cabling, or the connections to servers and other devices should all be checked for physical faults. Even if nothing obvious turns up, it doesn’t hurt to restart devices. Turning a computer, router, or modem on and off again may fix connectivity issues.

If hardware isn’t the problem, more testing will be required. If this is the case, I would try to gather as much information about the errors as possible and try to replicate it myself. This will help me understand where the problem is coming from. I would start by checking the logs on the network’s security and monitoring software to see if any unusual activity has been detected. I might need to investigate symptoms, or use command-line tools to figure out where the problem lies, like pinging a host or tracing a network route. I could also use network troubleshooting applications, like a packet sniffer or wifi analyzer, to see if they can provide any insights.

5. Can you explain TCP/IP?

TCP stands for Transmission Control Protocol. TCP is the communication standard that allows computers and other devices to communicate across a network.

IP stands for Internet Protocol. IP is the standard for sending data across the internet. Every computer in a network using IP has a unique IP address, which identifies it and allows it to send and receive communications.

Broadly speaking, TCP is the architecture that transports data across the network, and IP is the architecture that defines the sources and destinations. Taken together, TCP/IP is the internet protocol suite: the set of protocols that the internet and other computer networks use to enable communication. TCP/IP is the framework that the internet as we know it today is built on.

6. What are the layers of the TCP/IP model?

There are four layers in the TCP/IP model: Application, Transport, Internet, and Network Access.

The Application layer is the layer that users interact with when accessing the internet. This layer refers to the applications used to access the network, including email clients, messaging applications, cloud storage software, and more.

The Transport layer establishes end-to-end connections between devices and protects against errors in the data being transmitted. It guarantees that the data is secure and reliable.

The Internet layer, sometimes called the Network layer, controls the flow of data that is sent across the network. It defines the protocols that enable the transfer of data across the network.

The Network Access layer refers to the hardware that enables communication across the internet. This includes cables, wireless routers, device drivers, and more. This is the layer that physically transmits the data between devices.

7. What are the layers of the OSI model?

The OSI model, or Open Systems Interconnection model, was the standard model for network communication that preceded the TCP/IP model. The internet does not use the OSI model, but it is still used by some networks. The seven layers are:

1. Physical layer
2. Data link layer
3. Network layer
4. Transport layer
5. Session layer
6. Presentation layer
7. Application layer

8. How would you respond to a DDOS attack?

A DDOS attack, or Distributed Denial of Service attack, is an attack on a server that attempts to block real users from accessing the server by overloading it with requests. In a DDOS attack, the attacker will attempt to use multiple computers or devices to send traffic to the target IP address until it is overwhelmed, so that legitimate users can no longer access it.

Ideally, organizations should prepare for DDOS attacks before they occur. Ensuring that servers and data centers are distributed across different locations and networks will make them more difficult to overwhelm, reducing the effectiveness of DDOS attacks. All data centers should have different paths they can use to deliver information and multiple points of failure. Organizations should also use network firewalls and load balancers to defend against DDOS attacks.

If a DDOS attack does occur, the first step to responding to it is to identify it. Sometimes it can be difficult to tell when a DDOS attack is taking place, as it may not crash the server instantly. To identify the attack, a network engineer can look for suspicious traffic, unusual traffic from a single IP or IP range, strange spikes in traffic patterns, and more.

Once the DDOS attack has been identified, defending can be difficult. One option is to scale bandwidth to match the attack, so no servers are overwhelmed. This can be costly, however. Another option is to identify the IPs the attack is coming from and throttle them, so that they can only access the server a limited amount, or block them entirely. If necessary, entire regions or countries can be throttled to limit access.

It is possible that these responses will block some legitimate traffic, but denying service to some users is better than denying service to all users as a result of a successful DDOS attack.

9. How would you prevent data loss as a network engineer?

Companies run on data, it’s more important than ever to ensure that as little data is lost as possible. As a network engineer, it would be my priority to ensure that servers and resources are distributed across different data centers, so that issues in one location won’t destroy or corrupt the data in the rest. Further, I would ensure that all data is backed up regularly, so that even if one set of data is lost, there will be a copy of it on a different device.

I would also ensure that everyone with access to the network uses strong firewalls and antivirus software to prevent malware from stealing or corrupting data.

Lastly, I would work with the company to create a set of guidelines and best practices for all employees so they can identify the common causes of data loss and know how to avoid them.

10. What do you do to stay up-to-date with network engineering technologies?

I think social media is a great place to stay current with network engineering trends and technologies. I read and participate in IT forums related to my field, like Hacker News and certain Reddit subreddits. I also like to keep up with thought leaders in my field by following them online, on platforms like LinkedIn and Twitter. I frequently have conversations–sometimes heated ones!–with other network engineers in these online spaces.

I also subscribe to several IT newsletters, and I attend a monthly network engineer meetup with a group of local people in the industry. In the technology space, people are always innovating and improving, so if you don’t make an effort to keep learning you will fall behind.

5 Key Network Engineer Interview Tips

Of course, preparing for an interview requires more than just brainstorming answers to network engineer interview questions. As your interview approaches, use these tips to get as prepared as possible

Write down your answers for common network engineer interview questions

A great way to prepare for a network engineer interview is to look up common interview questions, and write down the answers you would give. This allows you to come up with answers ahead of time, and revise and refine them so that they are perfect by the time the interview comes. Of course, you can’t read from notes in the interview, but writing down your answers when you’re getting ready will help you memorize them for when the time comes.

Practice answering interview questions in the mirror

Once you have come up with answers for all the most common interview questions, practice saying them in a mirror or webcam so you can see what you look like as you answer. Appearing calm and confident matters almost as much as the answer itself. If possible, doing a full practice interview with a friend or career coach is a great way to get feedback on your speech and body language.

Research the company and the network engineering role

When you interview for a network engineer position, you don’t just want to seem like a good employee in general. Rather, you want to seem like the perfect employee for this specific role at this specific company. To do this, it’s important to know what the company is looking for.

For this reason, you should always research the company as much as possible before the interview. Try to get a sense of what they do, the network engineering technologies they use, and the company culture. The better you can fit in, the better the interview will go.

Test your technology

In the tech field, the first interview will probably be done remotely. If this is the case, make sure to get your camera, microphone, and wifi, as well as the video software you will be using, ready for the interview ahead of time. Any technical difficulties on your end will instantly bring your skills as a network engineer into question. You want the interview to go smoothly, with no dropped calls or bad audio.

Dress for a professional network engineer role

Even if you are doing a remote interview, make sure to dress appropriately for the office. Your clothes are one of the first things people notice about you when they see you, so it’s important to dress professionally. If your research into the company revealed their dress code, you can use this to decide the best outfit for the interview.