Network Engineer Interview Questions

Responsibilities 

Network engineer responsibilities may include:

• Designing system configurations
• Scheduling upgrades
• Administering firewall environments
• Auditing IP addresses and hosted devices
• Providing technical support to users

Skills

A poorly designed network can become a headache for its users. In order to design an effective network, a skilled network engineer will:

• Possess an eye for detail to observe flaws within the network
• Stay on top of emerging trends within the industry
• Communicate clearly with users to provide effective technical support
• Prioritize issues in order to solve them as quickly as possible
• Take into account network requirements in order to design appropriate infrastructure

Qualifications

In order to gain an entry-level position, candidates will need to possess at least a bachelor’s degree in computer science or a related mathematics field. However, most employers will want a candidate with a master’s degree in a related field. Additionally, most jobs will want candidates to have at least three years of experience with IT systems or network administration.

If you’re getting ready to interview for a position as a network engineer, you can prepare by researching the company as much as possible. Learn about the 9 things you should research before an interview.

Salary

Salaries for network engineers range between $68K and $109K with the median being $87K. 

Factors impacting the salary you receive as a network administrator include:

• Degrees (bachelor's, master's)
• Years of Experience
• Location
• Reporting Structure (seniority of the manager you report to and number of direct reports)
• Level of Performance - exceeding expectations

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Network Engineer Interview Questions

Question: Can you discuss what a network topology is?

Explanation: This is an opening question which the interviewer will ask to begin the conversation, learn more about your background, and gather information they may need for future questions.

Example: “The network topology is simply a physical description of an organization’s computer network. It illustrates where the individual systems are, how the cables are connected, and other features of the hardware and communication backbone.”

Question: Please tell me what a router is and what its functions are?

Explanation: The interviewer is continuing to explore your knowledge and experience in network management. This is a relatively simple question about one of the components of the network. In addition to confirming your qualifications for this role, questions like this will also help them understand your communication style and how you go about explaining things to people who may not have a technical background.

Example: “A router as a piece of hardware that manages the communication between different networks and devices. Its functions include managing communication between different networks, selecting the best path for devices to communicate, and forwarding and filtering packets.”

Question: What criteria are used to determine the best path selection for a router?

Explanation: This is a follow-up question to the previous one. During an interview, you should anticipate follow-up questions any time you provide the interviewer with an answer. Keeping your answers short and to the point will enable the interviewer to ask a follow-up question or encourage them to move on to the next topic.

Example: “There are several criteria used to define the path selection for a router which include matching the longest prefix, selecting the minimum administrative distance, and determining the lowest metric value. Using these criteria, you can define a router path which provides the best performance with the least amount of interference.”

Question: Please define anonymous FTP and how you use it as a network engineer.

Explanation: This is a technical question asking you to define a term used in this profession. As a network engineer, the majority of questions you’ll be asked during an interview will be technical questions. Technical questions are best answered succinctly and directly with little embellishment. The interviewer will ask a follow-up question if they need additional information about the topic.

Example: “FTP, as you may know, stands for file transfer protocol. This is a methodology used to upload and download files across the network. By definition, anonymous FTP grants user access to files on public servers without disclosing their identity.”

Question: What differences are there between a standard and an extended access control list or ACL?

Explanation: This is another technical question. However, in this one, the interviewer is asking you to compare two variations of the same term. When asked to do this, you start by defining each term then discussing the differences. You may also want to include an example of how each of them is used.

Example: “There are two fundamental types of an access control list or ACL. A standard ACL is source-based, whereas an extended ACL is both source- and destination-based. The extended ACL provides more control over what resources each user can access across the network.”

Question: TCP/IP has how many layers, and what are their names?

Explanation: This is yet another technical question. By now, you should recognize them and know how to formulate your answer. Again, keep in mind the interviewer is likely to ask a follow-up question about part or all of your answer.

Example: “TCP/IP, which stands for transmission control protocol/internet protocol, has four layers which include the network layer, the internet layer, the transport layer, and the application layer. Each of the layers deals with a different element of the network as designated by the name.”

Question: What is a DNS, and how is it used on the internet?

Explanation: This technical question is asking you to define the term and describe how it is used. As the interview progresses, the technical questions will become more difficult and specific. This is an indication that the interviewer is gaining confidence in your qualifications and is willing to explore more complex topics to examine the scope of your knowledge.

Example: “DNS, which stands for domain name system, is a fundamental part of the internet. Its function is to match the names you use to search for a web site with the website’s internet protocol or IP address. The IP address is a set of numbers. Being able to search for a name instead of the numbers makes finding resources on the internet much easier.”

Question: What are the differences between a forward lookup and a reverse lookup in the domain name system?

Explanation: You have probably already recognized this is a follow-up question to the previous one. As mentioned before, follow-up questions are common during an interview. Keeping your answers short and to the point allows the interviewer to ask follow-up questions and enables you to elaborate on your previous answer.

Example: “As mentioned earlier, a DNS allows users to search for websites using key terms or the website’s probable name. The DNS completes the search using two methodologies. The first is forward lookup which converts the name into the IP address. The second is reverse lookup which resolves the IP address into the website’s name. Both methods result in connecting the user to the appropriate website they are searching for.”

Question: Can you name the different layers in the OSI reference model?

Explanation: This is another technical question asking you to define a term and its components. You can prepare for the technical questions you will be asked during an interview by first reviewing the job posting so you clearly understand the requirements. Next, you should perform research on the company, its services, and products. This will give you an idea about the technology the organization uses. Take some time to review the standard terms, processes, and procedures used in this profession. This is similar to studying for an exam when you were in school.

Example: “The open standards interconnect, or OSI reference model, defines seven distinct layers within a network. These layers include the physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer.”

Question: Which layer of the OSI model does a gateway work in?

Explanation: This is another follow-up question. As we discussed, you should always be prepared for follow-up questions during the interview. By keeping your previous answer short, you encourage the interviewer to ask a follow-up question. If this provides you an element of control during the interview, you can guide the interviewer into areas you are most familiar with and comfortable talking about by keeping your answer short.

Example: “A gateway, which is a device that controls internet traffic and routes it to the appropriate pathway, exists within the transport layer of the OSI model.”

Additional Network Engineer Interview Questions

• How would you add a few hundred connections to a network that already has thousands of connections?

• Have you ever had a disagreement with a co-worker? How was it resolved?

• What type of protocol is OSPF?

• How do you know if a port is open or not?

• Have you ever failed at a major project?