Top 50 Network Security Interview Questions and Answers

17-May-2022

A brief overview of the Network Security Interview Questions

If you're seeking a career as a network security engineer or administrator, you'll need to prepare for a series of network security interview questions and answers. Knowing how to answer common network security interview questions can help you position yourself as a capable candidate with a thorough understanding of the topic. This article will assist you in dealing with any form of interview question.

Before we go into the detailed articulation of the best network security interview questions, you must have clarity of the concept and its relevance in the world we live in.

Organizations regardless of the size, rely on digital information and the internet for business operations in today's business environment. 

To take advantage of the internet's potential, an increasing number of businesses are constructing networks. Internal networks, on the other hand, become subject to attacks and hacking when they begin sharing information over the internet. This necessitates securing the network and all of the data housed inside it. Further security breaches could have a detrimental impact on corporate operations as well as the company's value or reputation. As a result, protecting the firm's network systems and data is important. Computer security, often known as cybersecurity, is a broad term that refers to the protection of data networks.

Best Network Security Interview Questions

When preparing for an interview, make sure you prioritize mastering the following network security interview questions and answers and prepare on areas aligning with the network security interview question given below.  

Subject-Matter based Network Security Interview Questions

1. What is a protocol?

It is a set of guidelines that governs all elements of information exchange.

2. Explain pipelining

Pipelining occurs when a task begins before the previous task has been completed.

3. What is the difference between a switch and a hub?

A switch is a control mechanism that turns the flow of electricity in a circuit, while a hub is a networking device that connects together numerous computers.

4. Name the various layers concerning OSI.

The various OSI layers are

• Data Link layer
• Transport layer
• Application layer
• Session layer
• Presentation layer

5. What layers make up the network support layers?

The network support layers are made up of the following:

• Data Link Layer 
• Network layer
• Physical layer

6. Define Simplex and give an example

Simplex is a sort of communication in which data is transferred in only one direction. Monitor, for example.

7. What exactly is RIP?

The Routing Information Protocol (RIP) is a straightforward protocol for exchanging data between routers.

8. What are the factors that influence network performance?

The following are the factors that influence network performance:

• Transmission media types
• Software 
• Hardware 
• Number of users

9. What's the difference between a wired and wireless local area network?

 Wired LAN devices included routers, hubs, and switches, and wireless LAN devices included MiFi routers and WLAN routers.

10. Give examples of user support layers.

The following are some of the user support layers:

• Presentation layer 
• Application layer 
• Session layer

11. What role does TCP play in IP packets?

The transmission control protocol is abbreviated as TCP. In a private network, it is utilized as a communications protocol. It allows application programs and computing devices to communicate over the internet. Its goal is to send packets from across the internet and make sure that the information and messages are successfully delivered.

12. Describe the various types of network data transfer faults.

There are two kinds of mistakes: Burst Error and Single Bit error

Burst error- It is a string of corrupt data that is measured from the first to the final error signal and includes it.

Single Bit Error - A single bit error happens when only a single bit of a data unit like a byte, packet, or character, is altered from 1 to 0 or 0 to 1. Single-bit mistakes are the least likely sort of error in the case of serial data transmission.

13. What are the protocols that use the application layer?

The protocols that make use of application layers are

• SMTP
• DNS
• TELNET
• FTP

14. What exactly is ALOHA?

ALOHA is an access control and management solution for a shared communication network channel. It is frequently used to address the issue of channel allocation. There are two varieties of ALOHA:

• Aloha Spirit
• Aloha with slots

15. Define intranet.

It's a private network based on TCP/IP protocols that's only available to corporate members or those with special permission.

16. What procedures are involved in generating the checksum?

The checksum is created by doing the following steps:

• Separate the information into sections.
• Using 1's complement arithmetic, add the portions together.
• Add the final sum to the complement.

17. Mention the various types of tools in Network Security

The different tools in Network Security are:

• Access control
• Antivirus and antimalware software
• Application security 
• Data Loss Prevention (DLP)
• Email security
• Firewalls
• Intrusion prevention systems
• Mobile device security
• Host-based Intrusion Detection System (HIDS)
• Network Intrusion Detection System (NIDS)
• Behavioral analytics
• Network segmentation
• Virtual Private Network (VPN)
• Web security
• Wireless security

18. Mention the various methods by which user authentication can be executed. 

The most common methods for user authentication are

• Biometric Authentication 
• Password Authentication Protocol (PAP) 
• Authentication Token

19. Explain how network security works at its most basic level.

Network security is an effort aimed at ensuring the network's and data's usability and integrity. It attacks a number of threats by utilizing solutions of both hardware and software. At the periphery and in the network, it integrates multiple levels of defenses. Different policies and controls are implemented at each network security layer. Malicious or unauthorized agents are prevented from executing exploits and threats while authorized users have access to network resources.

20. What does AAA signify in terms of network security?

AAA means Authentication, Authorization, and Accounting. It is the protocols that mediate the network access. It's a system for controlling user access, enforcing rules, and tracking all network activities. Radius and Diameter are two network protocols that provide AAA capability.

Authentication determines whether or not a user is authorized to use the system and network. A username and password are required.

Access control privileges are referred to as authorization. It means that, depending on their position in the business, each user on the network can only access particular data and information.

Accounting aids in the collection of all network activities for each use.

21. Explain the concept of IPS in network security?

Intrusion Prevention System is what IPS stands for. IPS monitors the network for any suspicious or malicious activity aimed at exploiting a known vulnerability. It detects suspicious activity and either allows (IDS) or stops (IPS) the threat. Signature-based, protocol-based, anomaly-based, and policy-based intrusion prevention systems are examples of intrusion prevention systems.

The IPS notifies system administrators of such incidents and takes steps to avoid future attacks, such as shutting access points and installing firewalls.

22. What do Administrator Privileges entail? Why are they required while installing a download?

Administrators offer permissions to users through administrative privileges. They can create, delete, and change items and settings with these privileges.

Most of the system modifications, like installing software or changing network settings, are impossible without administrative access. We may be able to use a program but not upgrade it in the absence of administrator access.

23. What are the probable ramifications of a network security breach for a company?

An enterprise can suffer irreversible damage as a result of a network security attack. 

The following are some of the possible results of a network security breach:

• Loss of confidential and sensitive information
• Profit reduction
• Shareholders' worth declines
• Brand value declines due to reputational damage
• Erosion of Customers' trust

24. Explain Network Encryption and its functionality.

The practice of encrypting or encoding data and messages sent across a computer network is known as network encryption. It covers a variety of tools, strategies, and standards for ensuring that messages transmitted between two or more network nodes are unreadable.

If unauthorized agents intercept information in transit, network encryption helps to safeguard the secrecy of information transferred across a network by making it even harder for them to comprehend it or gain anything beneficial from it. Each message is encrypted before being decrypted and converted back to its original format at the recipient's end applying encryption/decryption keys.

25. Explain CIA Triad in network security?

Confidentiality, Integrity, and Availability are the acronyms for Confidentiality, Integrity, and Availability. The CIA, sometimes known as the CIA Triad, is a prominent paradigm for maintaining privacy policies in enterprises. Security experts assess threats after determining their potential influence on the confidentiality, integrity, and availability of the organization's assets. 

A network is termed secure only when it possesses the three principal components that are - the CIA Triad. 

• Confidentiality is the method in which data of an organization is kept private and secret with concerted effort. As a result, only individuals who are authorized have access to specific assets, while those who are not are barred.
• Integrity refers to the assurance that data is genuine and trustworthy. 
• Systems, programs, and data must be available at all times, and authorized users must have access to resources when they are needed.

Device/ Application-Based (Firewall) Network Security Interview Questions and Answers

26. What are the advantages of using a firewall?

Firewalls provide the following advantages:

• Monitoring Network traffic 
• Prevents Spyware 
• Improves privacy
• Protect against Hackers
• Prevents virus attacks

27. What is the purpose of a proxy firewall?

An early type of firewall device, a proxy firewall, functions as a gateway from one network to another for a specific application. The network resources are protected by a proxy firewall by the method of filtering messages at the application layer. The firewall proxy server functions at the application layer through the proxy. This is accomplished by generating and executing a firewall process that mimics a service running on the destination host.

28. What is the purpose of a UTM firewall?

Unified threat management (UTM) firewall is a hardware or software device that combines a proxy, packet filtering, intrusion detection, and prevention systems, malware protection, application control, and other security capabilities.

29. Explain stateful inspection.

Stateful Inspection, often known as dynamic packet filtering, is a firewall mechanism that monitors the status of active network connections. It records all activities from the time a connection is established until it is terminated. It uses information about active connections to allow or restrict traffic based on state, port, and protocol.

30. Why do network firewalls prevent Active FTP from working?

Two TCP connections are formed upon the initiation of a connection to the FTP server. The connection of the second TCP is started and established by the FTP server (FTP data connection). If there is a firewall between the FTP client and server, the connection initiated from the FTP server will be blocked because it is launched from the outside. As a result, Passive FTP or modifying the firewall rule to add the FTP server as trusted can be used.

31. Explain VPN

VPN is an acronym for Virtual Private Network. It establishes a secure network connection over an open network such as the internet.

32. Explain the utility of a VPN?

A VPN is an encrypted link between a device and a network over the Internet. It creates a private network from a public internet connection to enable online privacy and anonymity. It keeps unauthorized parties from watching your traffic and allows you to work from wherever.

33. How are VPNs Classified?

VPNs are classified as follows:

• Site-to-site
• and  remote access

34. Give a brief explanation of Shadow IT?

The usage of information technology systems, software, devices, apps, and services without telling the organization's IT or security division is known as shadow IT. It comprises projects that are managed outside of the IT department and without the knowledge of the IT department.

With the advent of cloud-based applications and services, this practice has increased at an exponential rate. Data breaches and potential compliance violations from shadow IT can pose major security concerns to a company.

35. State a few examples of Shadow IT.

Shadow IT refers to all IT-related activities and purchases that the IT department is unaware of. It comprises all projects carried out in accordance with the company's stated rules. 

The following are some examples categorized in different ways: 

• Hardware: PC, Tablets, Laptops, external drives, flash drives, smartphones, etc.
• Productivity Tools- Slack and Trello
• Communication Program- VOIP and Skype
• Packaged Software
• Cloud Services- SaaS, IaaS, PaaS
• Threats-based Network Security Interview Questions

36. What exactly is a DDoS attack?

A DDoS (Distributed Denial-of-Service) attack is a type of cyber-attack in which the central server is constantly inundated with data requests. The goal of such attacks is to bring down the target system and business. A DDoS assault occurs when hackers interrupt the services of a host connected to the Internet, rendering a network resource (a website or computer system) unavailable to its users. It is accomplished by inundating or crashing the website with excessive traffic.

37. How are DDoS attacks categorized?

DDoS assaults are divided into three categories:

• Attacks based on volume – they use a large amount of traffic to overload the network bandwidth.
• Protocol attacks- They are designed to take advantage of server resources.
• Application attacks- They are the most serious sort of attack since they target online applications.

38. Explain Ransomware. 

Ransomware is a sort of harmful software that allows hackers to prevent you from accessing your data. The data of the victim is encrypted until the attacker receives a predefined ransom payment, which is commonly made in bitcoin. Email phishing and exploit kits can both be used to spread ransomware. The ransomware encrypts specified files and tells the victim of the required payment after it is distributed.

39. What is the mechanism of Ransomware? How does it work?

Ransomware can infiltrate your network in a variety of ways. Downloading a spam email attachment is the most usual method. The ransomware program will be downloaded and infect your computer. Social engineering, malvertising, and malicious software downloads are some of the various ways ransomware is spread.

The program enters your network via an executable file contained in a zip folder or other attachment. After that, the download file encrypts your data, adds an extension to your files, and makes them inaccessible.

40. Give examples of some common types of ransomware. 

They are:

• CryptoLocker
• WannaCry
• Bad Rabbit
• Cerber
• Crysis
• CryptoWall
• GoldenEye
• Jigsaw
• TeslaCrypt
• TorrentLocker
• Locky

41. Define Malware

Malware is a derivative of Malicious Software. It refers to software versions such as viruses, worms, adware, ransomware, worms, adware, and spyware that are designed to harm and destroy data and systems, as well as gain unwanted network access. Malware is typically distributed by email as a link or a file. To run the malware, the target must click on the link or open the file.

42. What is Spyware?

Spyware is unwelcome software that infiltrates your computer and sends information to a remote user. It steals your personal information and internet usage statistics. It is malicious software that, without your awareness, gains access to or destroys your computer. It is typically used to steal financial or personal data.

43. Define adware?

Adware is malicious software that collects information about your computer activities and displays relevant advertising on your screen, usually through a web browser. Although adware is not always dangerous, it can cause problems for your computer. It can lead you to dangerous websites and potentially contain Trojan horses and spyware.

44. Explain Phishing

Phishing is the deception of sending fraudulent emails, phone calls, or text messages to targets that look to come from a trusted source. By appearing as a reputable source, it lures the target into revealing passwords, credit card numbers, and other personal information, or into installing malware on the victim's PC. This is a form of social engineering.

45. Explain the process of phishing?

Phishing is a social engineering assault that allows hackers to acquire sensitive information from victims, such as login credentials and credit card details. It all starts with a fraudulent email or other kinds of communication, such as a text message, designed to entice a victim. The communication seemed to have come from a reliable source.

Phishers persuade victims to open those emails or text messages, and then entice them into disclosing confidential information, which has disastrous consequences. Hackers can corrupt pcs with viruses and persuade users to assist in money laundering in addition to stealing sensitive data.

Career-Based Network Security Interview Questions and Answers

46. Is working as a network engineer a wise choice?

In the current era, businesses seek network security professionals to safeguard sensitive data such as personal information and defend their businesses from dangers. Today, network security roles are among the most in-demand in the IT business. Despite the high demand for network engineers, there is a scarcity of suitable individuals to fill the position. Furthermore, the pay and promotion potential is excellent. As a result, a career as a network engineer can be both thrilling and profitable.

47. What does a Security Network Expert do?

A Network Security Expert professional performs to protect and safeguard the IT infrastructure of the organization.  They increase network security by utilizing techniques that include the following:

Intrusion detection systems, 

Encryption

Digital certificates.

48. What are the most popular job designations for Network Security

A Network Security Expert can go for any of the following job positions

• Network Engineer
• Systems Engineer
• Network Architect
• Network Support
• Systems Support Engineer
• Network Administrator

49. What are the essential abilities of network security experts?

The following are the essential abilities for a network security professional:

Technical Knowledge –

• Threat Modeling Knowledge
• Virtualization Technologies Knowledge 
• Secure Network Architecture Knowledge
• Vulnerability Testing 
• Understanding of Cloud Security Proficiency
• Understanding of Secure Coding Practices 
• Knowledge of security frameworks, firewalls, and data encryption programs;

Soft Skills - 

• Personality Qualities
• Communication skills
• Innovative
• Collaboration
• Problem-solving

50. What are the roles and responsibilities of a Network Security Engineer?

A Network Engineer's roles and responsibilities include the following: 

• New network solutions are being designed and implemented.
• Network equipment installation and configuration
• Increasing the effectiveness of existing networks
• Purchasing network equipment and overseeing network installation subcontractors
• Increasing the network's efficiency
• Monitoring and troubleshooting network performance
• Fault detection in the network
• Network equipment upgrade
• Notifying important stakeholders about network status

Whether you're trying to break into the world of network security or just want to brush up on your skills, training, and education are essential. And preparing for your network security interview will have a massive boost when you familiarise yourself with the most common network security interview questions and answers which also, add to your knowledge base with certification courses.

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