Network Administrator Interview Questions

Responsibilities

Network administrator responsibilities may include:

• Communicating with staff members to identify network problems
• Installing network systems
• Auditing processes
• Monitoring computer logs
• Creating programs to make the network more efficient

Skills

Computer networks are the platforms that business software runs on. In order to keep a business's network running smoothly, a skilled network administrator will:

• Possess an eye for detail to observe disturbances within the network
• Communicate with customers in order to troubleshoot effectively
• Convert technical data into easily understandable reports
• Think critically to understand how fundamental IT concepts relate to network administration
• Demonstrate quick thinking to mitigate issues as quickly as possible

Qualifications

To qualify for an entry-level position, candidates will need at least a bachelor’s degree in computer science or a related field. Higher level or management positions will typically require that candidates have a master’s degree.

Candidates can further distinguish themselves by earning certifications such as the CCNA offered by Cisco.

If you’re getting ready to interview for a position as a network administrator, 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 administrators range between $73K and $119K with the median being $95K. 

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, number of direct reports)
• Level of Performance - exceeding expectations

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Network Administrator Interview Questions

Question: What attracted you to the field of information technology (IT) and to become a network administrator?

Explanation: This is an example of a general or opening question. You will be asked this early in the interview for several reasons. This question enables the interviewer to get you talking, gives them an overview of your background, and provides information they can use to ask additional questions.

Example: “Ever since I was young, I have always been attracted to technology. It started with online gaming and progressed to writing code and developing simple applications. I continued to pursue this interest through high school and college. While still in college, I took a job as a network administrator in the school's IT department. After that, there was no looking back. I enjoy the challenges this profession presents in solving difficult and complex issues. I can’t think of anything else I’d rather do.”

Question: Can you explain what a firewall is and why it is important?

Explanation: This is your first technical question. As a network administrator, you can expect the majority of questions you will be asked during an interview will be technical. As you progress through the interview, the difficulty of the questions will increase. You shouldn’t have any trouble dealing with technical questions if you’re qualified for the job.

Example: “A firewall is an application that monitors traffic to and from a network and only allows legitimate information and connections to pass through it. Firewalls can be configured in either a highly secure or loosely secure manner. Firewalls are especially useful when an organization has remote workers who need to access sensitive company information.”

Question: What is TCP/IP?

Explanation: This is another technical question in which the interviewer is asking for a simple definition of a networking technology.  Technical questions are best answered directly and succinctly. In addition to providing the definition, you may want to include an example of how the technology is used.

Example: “TCP/IP stands for transmission control protocol/internet protocol. It establishes a connection between computers before any data is exchanged between them. It acts as the highway for data packets being sent back and forth and is used by various other protocols such as HTTP or FTP. TCP also sorts out data packets to ensure they are received in the proper order.”

Question: What is the difference between HTTP and HTTPS?

Explanation: By now, you should recognize this as another technical question. It is a little different in that it is asking you to compare two types of networking technology. Again, provide a definition of each of these terms and then give an example of how they’re used or what the key differences between them are.

Example: “HTTP stands for hypertext transfer protocol. Websites use this technology as a means of transmitting data. It also allows hyperlinks to be used to direct inquiries to the correct location. HTTPS is simply a secure version of HTTP that enables identity verification and low-level encryption.”

Question: What is a proxy server, and how is it used in directing traffic across the network?

Explanation: As you can see, the technical questions are becoming a little more difficult. This time the interviewer is not only asking for the definition, but they also included a specific question as to how the technology is utilized. Continue to answer this question as you did the previous technical ones.

Example: “A proxy server is not a piece of hardware but rather a software application that redirects network traffic and allows administrators to filter the traffic. It allows network administrators to monitor web traffic, provide access to specific websites, and block others. It also hides the point of access of network traffic to reduce spam and hacking attempts.”

Question: Can you explain what UDP is?

Explanation: While most casual users of the internet understand some of the previous terms you were asked about, only experienced network administrators will be familiar with this term. The interviewer is looking to distinguish you from the casual users and further qualify your network administration skills and knowledge.

Example: “UDP stands for user datagram protocol. Unlike TCP, which sends out packets only when requested, UDP is constantly sending a connection signal. This allows for faster connection speeds. UDP sends out data without consideration of what is receiving it. It is analogous to a broadcast radio signal.”

Question: What is the loop-back IP address?

Explanation: This is another technical question which only qualified network administrators will be familiar with. Since this process is used to test the network, most users probably have never heard of it which illustrates why you should prepare for an interview by reviewing common as well as complex network administration terms and tools.

Example: “The loopback IP address is 127.0.0.1. This differs from common IP addresses with a typical format of 192.168.0. The purpose of the loop-back IP address is for troubleshooting network connectivity issues. It is commonly used to test network interface cards for functionality. If you ping this IP address and it successfully returns a signal, it means your hardware is okay.”

Question: What is FTP, and which specific ports does this protocol use?

Explanation: The interviewer is continuing to delve deeper into your technical knowledge. This question not only asks for a definition of the term, but now they’re expanding their questions to network hardware. Keep in mind that the job of a network administrator involves both hardware, network traffic, and software. You should be well versed in each of these technology categories.

Example: “FTP stands for file transfer protocol. It is used to transfer large files between computers and has the built-in ability to pause the transfer of data when appropriate. There are many FTP tools and applications available across the internet. Specific ports used by FTP are 20 and 21.”

Question: What is the maximum length of UTP cable allowed?

Explanation: This is another hardware-related question testing your knowledge in this area. Since the interviewer used an acronym, you may want to start your answer by defining what UTP means and then answer their question about the length.

Example: “UTP stands for unshielded twisted pair cable. This type of cable is used for both network and telecommunications connections. By twisting conductors from the same circuit around each other, the cable is shielded from electromagnetic interference or EMI. The maximum length for a UTP cable is 100 meters for any single segment. Switches and repeaters are placed between segments to overcome this limitation.”

Question:  How many layers are in an OSI model, and what are they?

Explanation: This question is similar to the previous one in that the interviewer only gives you the acronym. Like before, define the acronym and then describe the layers which the interviewer is asking about. Keep in mind that as the questions become more difficult, the interviewer is becoming more convinced of your qualifications and will likely end the interview soon in a positive manner.

Example: “The OSI (open systems interconnection) model describes the functions of a network telecommunications system. There are seven layers to the OSI model, much like the infamous bean dip served at Super Bowl parties. These layers include the physical layer, data link, network, transport, session, presentation, and application.”

Additional Network Administrator Interview Questions

• How would you handle an angry customer who is having technical issues and needs to work immediately?

• What is HTTPS, and what port does it use?

• What are IP classes?

• What is the difference between a switch and a router?

• What types of load-balancing methods are available? What is the best?