Top 20 Interview Questions & Answers for Network Engineer L1 – 2025

As technology continues to advance, the demand for network engineers has never been higher. Whether you are a seasoned professional or just starting out in your career, these questions and answers will help you prepare for your next network engineer L1 interview. Showcase your technical skills, experience, and problem-solving abilities with these top 20 interview questions.

General Questions

• 1. Tell us about your experience working as a network engineer L1.
  As a network engineer L1, I have been responsible for the maintenance, troubleshooting, and monitoring of network infrastructure. I have experience working with a variety of equipment and technologies, including routers, switches, firewalls, and wireless networks. I have also worked with various network protocols and configurations to ensure smooth and efficient network operations.
• 2. What motivated you to become a network engineer L1?
  I have always been fascinated by technology, and the idea of building and maintaining networks was something that greatly appealed to me. I enjoy solving complex problems and working with cutting-edge technologies to ensure smooth network operations for businesses and organizations.
• 3. What do you consider to be the most important skills for a network engineer L1?
  The most important skills for a network engineer L1 include strong technical knowledge and troubleshooting abilities, attention to detail, time management, and excellent communication skills. A network engineer L1 should also have a good understanding of network security and be able to adapt to new technologies quickly.

Technical Skills & Experience

• 4. Can you explain the OSI model and how it is used in network engineering?
  The OSI (Open Systems Interconnection) model is a conceptual framework used to describe how data is transferred between devices in a network. It is divided into 7 layers, each with its own unique function. As a network engineer L1, I use the OSI model to troubleshoot network issues, as it helps me to identify where the problem is occurring and how to resolve it.
• 5. What is the difference between TCP and UDP?
  TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are both protocols used for communication over the Internet. The main difference is that TCP is a connection-oriented protocol, meaning that data is transferred between devices in a sequence and checked for errors along the way. UDP, on the other hand, is a connectionless protocol, meaning that data is sent without establishing a connection and is not checked for errors. TCP is used for reliable data transfer, while UDP is used for real-time applications such as video streaming.
• 6. What is the difference between a router and a switch?
  Routers and switches are both used in network infrastructure, but they have different functions. A router connects networks and directs traffic between them, while a switch connects devices within a network and manages data flow between them. In simple terms, a router connects different networks, while a switch connects devices within a network.
• 7. Can you explain the difference between a LAN and a WAN?
  A Local Area Network (LAN) is a group of computers and devices connected in a small geographical area, such as an office, while a Wide Area Network (WAN) is a group of LANs connected together to form a larger network, often spanning multiple geographical locations. While LANs are usually owned and managed by a single organization, WANs are often owned by multiple organizations and are used for widespread communication and data sharing.

Behavioral Questions

• 8. Can you tell us about a time when you successfully troubleshooted a network issue?
  In my previous role as a network engineer L1, we encountered an issue where the network was experiencing frequent drops in network connectivity. After investigating and running diagnostic tests, I discovered that the issue was due to a misconfigured switch. I reconfigured the switch, and the issue was resolved, resulting in improved network performance for our organization.
• 9. Have you ever had to handle a high-pressure situation in your role as a network engineer L1? How did you handle it?
  As a network engineer L1, there will be times when issues need to be resolved urgently, and it can be a high-pressure situation. In one instance, the network was down for a critical client due to a failure in our primary router. I quickly identified the problem, implemented a backup router, and restored network connectivity, meeting the client's requirements and minimizing downtime.
• 10. How do you handle conflicts with team members or other departments while working on a project?
  Conflicts can arise in any workplace, but as a network engineer L1, it is crucial to work well with others to ensure the success of a project. When conflicts arise, I calmly listen to all parties involved, communicate openly and respectfully, and work towards finding a solution that benefits everyone involved. I believe in being a team player and always strive to maintain positive working relationships with my colleagues.

Situational Questions

• 11. In your current role as a network engineer L1, how do you ensure network security?
  In my current role, I am responsible for regularly monitoring network traffic and implementing security protocols to protect against potential threats. This includes implementing firewalls, intrusion detection systems, and regularly updating network security measures to keep up with the latest threats and vulnerabilities.
• 12. If a new technology or software was introduced to the network, how would you go about familiarizing yourself with it?
  As a network engineer L1, it is important to stay updated with the latest technologies and be able to adapt to new systems quickly. If a new technology or software was introduced, I would first read up on the documentation and familiarize myself with its functions and capabilities. I would also seek guidance from more experienced team members, attend training sessions, and conduct my own research to gain a comprehensive understanding of the technology.
• 13. How do you approach complex network troubleshooting tasks with minimal information?
  In such instances, I usually start by gathering as much information as I can from users and system logs. I then use my knowledge and experience to narrow down possible causes and conduct diagnostic tests to determine the root cause of the issue. I also collaborate with my team members to brainstorm and troubleshoot the issue together, as it can often lead to a quicker resolution.

Cultural Fit Questions

• 14. What motivated you to apply for a role in our company specifically?
  I was drawn to your company's reputation for being at the forefront of technological advancements and for your commitment to providing top-notch services to clients. I am always looking for opportunities to learn and grow, and I believe that this company would provide me with the support and resources to do so.
• 15. How do you keep up with advancements and changes in the networking industry?
  As a network engineer L1, it is crucial to stay updated with the latest advancements and changes in the industry. I regularly attend workshops and training sessions, read industry blogs and publications, and participate in online forums and communities dedicated to networking. This allows me to stay informed and adapt to new technologies and practices quickly.
• 16. How do you prioritize and manage your tasks as a network engineer L1?
  In my role, it is essential to prioritize tasks and manage my time effectively to meet deadlines. I use a project management system to keep track of all my tasks and prioritize them based on urgency and importance. I also communicate regularly with my team to ensure that everyone is on the same page and that our workload is balanced.

Additional Technical Questions

• 17. What is the purpose of DNS, and how does it work?
  DNS (Domain Name System) is used to translate human-readable domain names (such as www.example.com) into IP addresses (such as 192.168.0.1) that can be understood by computers. This is important because it allows users to access websites and other resources using easy-to-remember domain names, rather than having to remember a string of numbers.
• 18. What is VLAN and how do you configure it?
  VLAN (Virtual Local Area Network) is a networking technology that allows for the segmentation of physical networks into smaller logical networks. This is useful for improving network performance, increasing security, and reducing network traffic. VLANs can be configured using switches by assigning ports to different VLANs based on the devices connected to them.
• 19. Can you explain the difference between IPv4 and IPv6?
  IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6) are both protocols used to identify devices on a network. The main difference is that IPv4 uses 32-bit addresses, allowing for approximately 4.3 billion unique addresses, while IPv6 uses 128-bit addresses, allowing for approximately 340 undecillion unique addresses. This allows for a significantly larger number of devices to be connected to the internet using IPv6.
• 20. What are the best practices for network security?
  Some best practices for network security include regularly updating security patches and ensuring strong password policies are in place, implementing firewalls and intrusion detection systems, monitoring network traffic, and maintaining regular backups of critical data. It is also important to educate employees on cybersecurity best practices and to conduct regular security audits to identify and address vulnerabilities in the network.