Network Security Essentials Interview Questions

The most important step to attain success in any exam is to prepare yourself for a job interview. The job interview is one of the crucial step that you will take in your journey. Since, it’s your best opportunity to present yourself to the recruiters and leave an unforgettable mark by performing in the best way. But before appearing for the interview it is very important to know about the basics of an interview. Therefore, one should keep these following points in mind before starting to prepare for the interview round:

Research about the company
Research about the job roles and responsibilities
Thinking about wearing decent \ formals for the interview
Having good communication skills
Build yourself on confidence
Preparing for questions that will be asked in the interview
Following up with the recruiters.

Moreover, we have discussed the Network Security Essentials Interview Questions and answers in the following sections. So candidates that are appearing for this exam tend to lack with the interview round, due to some reasons like not having much information regarding the company, job role and most importantly unaware of the most probable questions asked in the interview. Therefore, follow us to boost your interview skills to ace the interview with flying colors.

Now, let’s begin with some of the best Network Security Essentials Interview Questions.

Advanced Interview Questions

What is a firewall and how does it work?

A firewall is a security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules and policies. Firewalls are typically implemented in hardware or software, or a combination of both.

Firewalls work by inspecting each packet of data that travels in and out of a network and comparing it to a set of rules or policies that have been established by the network administrator. These rules or policies determine whether or not the packet should be allowed through or blocked.

There are two main types of firewall:

Network firewall: This type of firewall is placed at the boundary between a private internal network and the Internet. It monitors and controls all incoming and outgoing traffic to and from the Internet.
Host-based firewall: This type of firewall is installed on individual hosts, such as servers or personal computers, and monitors and controls incoming and outgoing traffic to and from that host.

Firewalls can also be classified into two main categories:

Stateful Firewall: These firewall inspect the packet, keep track of the state of the connection and make decision based on the state.
Stateless Firewall: These firewalls only inspect the packet header, doesn’t keep track of the state of the connection and make decision based on the packet header.

Some firewalls also include additional features such as intrusion detection and prevention, which can detect and block known attacks. Firewalls can be a very effective tool in securing a network, but they should be used in combination with other security measures such as anti-virus software and strong passwords.

Can you explain the difference between a DMZ and a VLAN?

A DMZ (Demilitarized Zone) is a network segment that is used to isolate an organization’s internal network from external networks, such as the Internet. It is typically used to host external-facing servers, such as web servers, that need to be accessible to the Internet while still keeping the internal network secure. A DMZ is typically implemented by using a firewall to segment the internal network from the DMZ, and then placing servers in the DMZ that need to be accessible to the Internet.

A VLAN (Virtual Local Area Network) is a logical grouping of devices on a network that allows for communication between devices as if they were on the same physical network, even though they may be physically separated by one or more switches. VLANs are typically used to segment a network into smaller, more manageable subnetworks. Each VLAN is assigned a unique identifier, known as a VLAN ID, which is used to identify the VLAN and allow devices to communicate within the VLAN.

In summary, a DMZ is a network segment used to isolate an organization’s internal network from external networks, while a VLAN is a logical grouping of devices on a network that allows for communication between devices as if they were on the same physical network, regardless of their physical location.

How do you secure a wireless network?

Securing a wireless network involves several steps to ensure that the network is protected from unauthorized access and potential threats.

Change the default login credentials for the wireless router to a strong and unique username and password.
Enable WPA2 or WPA3 encryption to protect the wireless network traffic from being intercepted.
Configure the router to use a strong and unique SSID, or network name, that is not easily guessable.
Disable the broadcasting of the SSID to make it harder for attackers to find the network.
Implement a strong guest network policy to limit the access and activities of guest users on the network.
Use a Firewall to prevent unauthorized access to the network by controlling incoming and outgoing network traffic.
Disable WPS (Wi-Fi Protected Setup) as it has known vulnerabilities that can be exploited by attackers.
Regularly check for and update firmware of the router to ensure it has the latest security patches.
Use a VPN for remote access to the network to ensure a secure connection.
Regularly monitor the network for any suspicious activity and take appropriate action if any is detected.

It’s essential to keep in mind that securing a wireless network is an ongoing process and requires constant monitoring and updating to keep up with new threats and vulnerabilities.

What is a VPN and how does it work?

A VPN, or Virtual Private Network, is a technology that allows users to securely connect to a remote network or computer over the internet. The main purpose of a VPN is to provide a secure and private connection to the internet, allowing users to access resources and services that would otherwise be restricted or blocked.

When a user connects to a VPN, they establish a connection to a remote server, which acts as a gateway to the internet. The user’s device then sends all internet traffic through this gateway, which encrypts the data and sends it to the destination. This encryption helps to protect the user’s data from being intercepted or accessed by unauthorized parties.

The VPN server also assigns the user a new IP address, which is used to identify their device on the internet. This helps to mask the user’s true location and makes it more difficult for websites and services to track them.

There are several different types of VPNs, each with their own unique features and benefits. Some of the most popular types include:

Remote Access VPNs: These are typically used by individuals who need to access resources on a remote network, such as a corporate network or a home network.
Site-to-Site VPNs: These are used to connect multiple locations or networks together, allowing users at different locations to access shared resources and services.
Mobile VPNs: These are designed specifically for mobile devices and are often used by people who need to access the internet while on the go.

Overall, a VPN is a powerful tool that can help protect your online privacy and security, while also giving you access to resources and services that would otherwise be restricted or blocked. Whether you’re working remotely, traveling, or just looking to protect your online activities, a VPN can provide you with the protection and flexibility you need to stay safe and connected.

Can you explain the difference between symmetric and asymmetric encryption?

Symmetric encryption and asymmetric encryption are two different methods of encrypting data.

Symmetric encryption, also known as private key encryption, uses one secret key to both encrypt and decrypt data. This means that the same key is used to encrypt the data before it is sent, and then to decrypt the data after it is received. Symmetric encryption is fast, but the major drawback is that if the key is compromised, the data can be easily decrypted.

Asymmetric encryption, also known as public key encryption, uses two keys: a public key and a private key. The public key is used to encrypt the data, while the private key is used to decrypt the data. Because the private key is kept secret and the public key is shared, only the person with the private key can decrypt the data. Asymmetric encryption is more secure than symmetric encryption, but it is also slower.

In practice, symmetric encryption is typically used to encrypt the actual data, while asymmetric encryption is used to encrypt the symmetric key that was used to encrypt the data. This provides a good balance of security and speed.

How would you prevent a SQL injection attack?

SQL injection is a type of cyber attack that aims to exploit vulnerabilities in a website or application’s database. It is done by injecting malicious SQL code into a web form or query, which can allow attackers to gain unauthorized access to sensitive information, modify or delete data, or even take control of the entire database. To prevent SQL injection attacks, there are several measures that can be taken:

Input validation: One of the most effective ways to prevent SQL injection is by validating user input. This can be done by ensuring that any input that is entered into a web form or query is in the correct format and does not contain any malicious code.
Use parameterized queries: Another effective way to prevent SQL injection is by using parameterized queries. This approach involves using placeholders in the SQL query and then binding the actual values to the placeholders at runtime. This ensures that any user input is treated as a value and not as part of the query.
Use prepared statements: Prepared statements are similar to parameterized queries, but they are pre-compiled by the database engine. This makes them more efficient and less vulnerable to SQL injection.
Use a web application firewall (WAF): A WAF is a security tool that sits between the web application and the internet, and it can be used to detect and block SQL injection attacks.
Regularly update software: Regularly updating software and database systems can help to prevent SQL injection attacks. Software vendors often release security updates and patches to address known vulnerabilities.
Use least privilege principle: By using least privilege principle, it reduces the risk of SQL injection attack by providing only the minimum access to the user needed to perform their job.

In summary, preventing SQL injection attacks requires a multi-layered approach that includes input validation, parameterized queries, prepared statements, a web application firewall, regular software updates, and the use of the least privilege principle. It is also important to stay informed about the latest threats and vulnerabilities, and to have a robust incident response plan in place in case an attack does occur.

What is a man-in-the-middle attack and how can it be prevented?

A man-in-the-middle (MitM) attack is a type of cyber attack where an attacker intercepts and alters communications between two parties without their knowledge. The attacker can read, modify, or even inject new information into the communication.

One common way that MitM attacks are executed is through the use of a rogue wireless access point. An attacker can set up a fake wireless access point that appears to be legitimate, and trick users into connecting to it. Once connected, the attacker can intercept and alter the traffic.

Another way MitM attacks are executed is by compromising a device on a network and using it as a point of entry to intercept communications. The attacker can use malware, phishing or other techniques to gain access to the device, then use it to intercept communications.

To prevent MitM attacks, there are several steps that can be taken:

Use secure protocols such as HTTPS and SSH, which encrypt communications and prevent attackers from intercepting and reading them.
Use a virtual private network (VPN) to encrypt communications and protect them from being intercepted.
Use a firewall to block unauthorized access to a network.
Use a wireless intrusion prevention system (WIPS) to detect and block rogue wireless access points.
Keep all software and systems up to date and patched to fix known vulnerabilities.
Use a endpoint protection software to detect and prevent malware.
Educate users on how to identify and avoid phishing attacks and other social engineering tactics.
Use network segmentation to isolate sensitive systems and data from the rest of the network.

It is important to note that no single solution can prevent all MitM attacks, so a combination of different security measures is necessary for effective protection.

Can you explain the difference between a vulnerability and a threat?

A vulnerability is a weakness or gap in a system or network that can be exploited by an attacker. It is a potential point of entry or weakness that can be used to gain unauthorized access or control of a system. Examples of vulnerabilities include unpatched software, weak passwords, or unsecured network connections.

A threat, on the other hand, is a potential or actual attack on a system or network. It is an action or event that has the potential to exploit a vulnerability and cause harm or damage. Examples of threats include hacking attempts, malware, or phishing scams.

In summary, a vulnerability is a weakness that can be exploited, while a threat is an action or event that attempts to exploit that weakness. It’s important to note that not all vulnerabilities will lead to a threat, and not all threats are able to exploit a vulnerability.

How do you keep software and systems up to date and patched?

Keeping software and systems up to date and patched is an important aspect of network security. This process helps to ensure that known vulnerabilities are addressed and that the software is running the latest version with the most recent security updates.

There are a few different ways to keep software and systems up to date and patched:

Automatic Updates: Many software applications and operating systems have the option to automatically check for and install updates. This can be a convenient way to stay current, but it is important to ensure that the updates are being installed from a trusted source.
Manual Updates: Some software and systems may not have automatic update capabilities, or the user may prefer to manually check for updates. In these cases, it is important to regularly check for updates and install them as soon as they become available.
Patch Management Software: This type of software automatically checks for and installs updates and patches for multiple systems and applications. This can be an efficient way to manage updates for a large number of systems and devices.
Vulnerability scanning: This is a process of identifying and assessing known vulnerabilities in the software, system or network. This can be done by using tools that check for known vulnerabilities.

It is important to keep in mind that updating and patching alone is not a guarantee of security, but it is a crucial step in maintaining the security of software and systems. Additionally, it is important to ensure that the systems are configured securely and that the users are trained to follow safe computing practices.

Can you explain the importance of incident response planning?

Incident response planning is crucial for organizations of all sizes and industries as it helps them prepare for, respond to, and recover from unexpected events that could potentially harm their operations, reputation, and bottom line. Here are some key reasons why incident response planning is important:

Mitigates damage: A well-designed incident response plan can help an organization quickly and effectively respond to an incident, minimizing the damage it causes. This can include containing the spread of a cyber attack, containing a fire, or evacuating a building during a natural disaster.
Enhances resilience: By planning for potential incidents, an organization can build resilience into its operations and systems. This helps ensure that critical systems and processes can continue to operate, even in the face of an incident.
Improves communication: A well-designed incident response plan includes clear lines of communication and roles and responsibilities for team members. This helps ensure that everyone knows what to do in the event of an incident, which can reduce confusion and speed up the response.
Meets legal and regulatory requirements: Many industries have legal and regulatory requirements for incident response planning. For example, healthcare organizations must comply with HIPAA regulations and financial institutions must comply with the Gramm-Leach-Bliley Act.
Protects reputation: An organization’s reputation can be severely damaged by an incident. A well-designed incident response plan can help an organization respond quickly and effectively to an incident, which can help mitigate the damage to its reputation.

Overall, incident response planning is essential for ensuring the safety and well-being of employees, customers, and other stakeholders, protecting the organization’s assets and operations, and complying with legal and regulatory requirements.

Basic Interview Questions

1. What is the need to use a 31-bit Subnet Mask?

The use of a 31-bit subnet mask is needed in scenarios where there is a need for point-to-point communication between two devices or networks. With a 31-bit subnet mask, a network can have only two usable IP addresses: one for the network address and the other for the broadcast address. This means that there is only one host allowed in the network, which is sufficient for point-to-point communication. Using a 31-bit subnet mask reduces the waste of IP addresses and provides efficient use of available IP address space.

2. What is the use of a 32-bit Subnet Mask?

A 32-bit subnet mask is used to identify the network and host portions of an IP address. It is used to partition a larger network into smaller subnetworks, allowing for more efficient use of available IP addresses and better network management. The 32-bit subnet mask also helps to improve network security by isolating different network segments and controlling access to them.

3. Can you use 32 subnet mask for a virtual external interface?

It is important to note that a 32 subnet mask cannot be utilized for a virtual external interface, such as a VLAN or Link Aggregation interface. The reason for this is that configuring a virtual external interface with a default gateway on a different subnet is not possible.

4. What is the primary purpose of using NAT?

In order to increase the number of computers that can operate off a single publicly routable IP address and to conceal the private IP addresses of hosts on your LAN, Network Address Translation (NAT) is commonly utilized.

5. List the different types of NAT supported by Firefox?

The Firebox supports three different types of NAT. They are:

Firstly, Dynamic NAT
Secondly, Static NAT
Lastly, 1-to-1 NAT

6. Explain Dynamic NAT?

Dynamic NAT, also referred to as IP masquerading, is implemented by the Firebox to assign its public IP address to outgoing packets for all connections or for specified services. This effectively hides the true IP address of the originating computer from the external network, making it an ideal solution for concealing internal host IP addresses when accessing public services.

7. What is the use of Static NAT ?

Static NAT (SNAT) is frequently used to provide surface computers access to public, internal servers. To configure static NAT, one can utilize a SNAT action and apply it when configuring policies. By doing so, the Firebox can map a single public IP address to a specific private IP address, making it accessible from the external network.

8. Why is Static NAT known as port forwarding?

Static NAT, which is also referred to as port forwarding, allows for a port-to-host NAT. When a packet is sent from a host on the surface network to a port on an external interface, the IP address is changed to an IP address and port located behind the firewall. This is an effective way to manage and secure network traffic.

9. Explain 1-to-1 NAT?

1-to-1 NAT involves mapping IP addresses from one network to another. This is typically only possible when multiple public IP addresses are available, or when servers require the same public IP address for traffic initialization.

10. Mention the two types of Firewall policies?

Firstly, the Packet filter policy
Secondly, Proxy policy or application layer gateways (ALG)

11. Explain the Packet filter policy?

Packet filtering is a common technique for examining IP and TCP/UDP headers, without examining the packet content. It is a straightforward method for identifying and blocking unwanted traffic.

12. Explain the Proxy policy or application layer gateways (ALG)?

A proxy policy or ALG opens each packet in a sequence, examines the network layer header, and inspects the packet payload. This allows for more granular content-based rules and actions, which can be configured to ensure optimal network performance and security. When implementing a proxy policy or ALG, it is important to select the appropriate proxy action and configure rules that are tailored to the unique characteristics of the network traffic.

13. What is Precedence?

The concept of precedence holds immense significance in the world of networking. It refers to the specific order in which the Firebox examines network traffic and applies the relevant policy rule. This sequence is of utmost importance since it ensures that the Firebox functions optimally and delivers efficient results. The process of assigning precedence involves careful consideration of various factors such as the type and sensitivity of the network traffic, the level of security required, and the organizational policies that need to be enforced. By meticulously prioritizing the policy rules and their corresponding network traffic, the Firebox is able to effectively manage and safeguard the network environment. Hence, understanding and implementing the correct precedence is vital to ensure smooth and secure network operations.

14. What do you understand by Auto-Order mode?

The default setting for Firebox policies is the Auto-Order mode, which functions by classifying policies from the most precise to the most general. This automatic classification is determined by a comparison of various policy properties. The Firebox employs this mode to streamline the configuration process, ensuring efficient and effective policy implementation.

The Auto-Order mode’s primary function is to automatically categorize policies in order of relevance and specificity, allowing for optimal firewall management. The process involves a comprehensive analysis of various policy attributes, including source and destination IP addresses, ports, and protocols. The Firebox performs this evaluation to ensure that each policy is appropriately placed within the configuration hierarchy.

The Auto-Order mode reduces the workload required for manual policy configuration, streamlining the entire process by prioritizing the most specific policies. This approach ensures that policies with the highest priority are executed first, enabling efficient traffic flow control. As a result, the Auto-Order mode minimizes the risk of errors and conflicts within the configuration, ensuring a secure and efficient network infrastructure.

15. List the advantages of private key infrastructure (PKI)?

Deploying certificates can be a daunting task, but with the right tools, it can be made easier. One option is to use an internal PKI instead of creating certificates on the Firebox. An internal PKI can simplify the process by allowing network clients to automatically trust certificates issued to the Firebox. This eliminates the need to manually install certificates on each individual client. Additionally, using third-party software can further simplify the deployment process. By utilizing these methods, replacing a Firebox does not require the redeployment of certificates to network clients. Overall, these strategies can save time and effort, while also improving the security and reliability of certificate management.

16. What is a feature key?

One of the essential components of your Firebox is the feature key. This key is responsible for unlocking a series of licensed features on your device, which significantly enhances its functionality. However, before you can start using your Firebox, you need to create a feature key first. This process is relatively easy and requires you to initiate the device on the WatchGuard website. Once you have completed this step, you can then install the feature key on your device, which enables all of the functions that the Firebox has to offer.

Without a feature key, your Firebox may not work to its full potential, which can significantly impact your network’s security and performance. Therefore, it is crucial to ensure that you create and install the feature key as soon as possible after purchasing a new device. By doing so, you can take full advantage of all the benefits that your Firebox has to offer, ensuring optimal protection and performance for your network.

17. What does the summary section of feature keys include?

The Summary section includes:

Overview of the product or feature.
Key benefits and value proposition.
Target audience and use cases.
Technical specifications or requirements.
Availability and pricing information.
Upcoming updates or enhancements.
Customer reviews or testimonials.
Contact or support options.

18. What does Features section of feature keys include?

Licensing of features: The Features section of feature keys includes the licensing of various features that your device can perform. This ensures that your device is up-to-date and that you can access all the latest features available.
Functionality: The feature key determines the level of functionality you can enjoy on your device. It allows access to features like web filtering, intrusion prevention, and VPN tunnels, among others.
User Management: The Features section of the feature key also enables you to manage your users effectively. This includes controlling access to specific features, ensuring that unauthorized users cannot access your network.
Network Security: The feature key is a vital aspect of network security. It provides the necessary security features to protect your network from threats like malware, viruses, and hacking.
Reporting: The feature key also enables reporting, allowing you to monitor your network’s performance and detect any potential threats.
Cloud Integration: The Features section of the feature key includes cloud integration, enabling you to connect to the cloud and access various cloud-based services.
Customization: The feature key allows customization, allowing you to tailor your device’s features to your specific needs. This ensures that your device works optimally for your business or organization.

19. What is a Backup image?

A backup image serves as a critical tool that enables you to restore your Firebox to a previous state. This file contains the essential configuration file, certificates, passphrases, feature key, and other unique information that your Firebox uses.

20. How will you keep the attackers out of your network?

When it comes to security, the default threat protection offered by the firewall is exceptional. It meticulously analyzes every packet that passes through the device, observing the source and destination IP address and port numbers. This process allows it to identify patterns and indicators of a potential attack. In the event of a threat, the Firebox can be programmed to take swift action and block the possible threat. This proactive approach to detecting and preventing attacks is an effective way to secure your network.

21. What is the use of Front panel?

The Front Panel page provides an overview of your device’s status, connected servers, network, and network traffic. This information is helpful in quickly assessing the overall health of your network.

22. What does interface page shows?

The Interfaces page offers an in-depth view of the active interfaces on your device, including wireless interfaces. Here you can see detailed information and current bandwidth usage. Additionally, you can renew or release the DHCP lease on any external interface that has DHCP enabled, allowing for further customization and control.

23. How to save the TCP dump data directly to a PCAP file?

Open the terminal or command prompt.
Type the command “tcpdump -w filename.pcap” (replace “filename” with the name you want to give to the PCAP file).
Hit enter to start the TCP dump process.
The data will be saved directly to the PCAP file in the same directory.
To stop the process, press Ctrl+C in the terminal or command prompt.

24. How will you Configure Logging to Dimension?

Access the WatchGuard System Manager (WSM)
Navigate to the Firebox settings
Click on the logging tab
Choose the option to send logs to a Dimension server
Enter the IP address of the Dimension server
Save the changes and test the connection

25. How is Geolocation page is useful?

By visiting the Geolocation page, users are provided with an opportunity to keep an eye on the movement of network traffic according to geographic location. This function is made possible by the implementation of the Geolocation feature.

26. What does Network Discovery page shows?

On the Network Discovery page, users can obtain an informative treemap view of all devices connected to their network interfaces on their Firebox. Additionally, users are able to access in-depth details for each connected device.

27. What details a Log message includes?

Source and destination IP addresses
Protocol type and port number
Date and time of the event
Event severity level
Description of the event
Any actions taken by the firewall
Information about the user, if applicable

28. What is the need of Traffic Monitor?

The Traffic Monitor page is designed to allow users to view log messages from their Firebox in real time, which can be utilized to troubleshoot network performance issues.

29. How can you monitor the connection status and activity on your WatchGuard AP devices?

Gateway Wireless Controller page enables users to monitor the connection status and activity on their WatchGuard AP devices. Furthermore, users can manage and observe client connections to one WatchGuard AP device.

30. How can you set up notifications in your policies?

Access the WSM
Navigate to the policy editor
Select the policy to which you want to add notifications
Click the “Advanced” tab
Click on “Notifications”
Choose the type of notification you want (e.g. email, SNMP, etc.)
Configure the settings for the notification
Save the changes to the policy.

31. List the different types of Network Modes supported by Firebox?

Different types of Network Modes are supported by Firebox: Bridge Mode, Mixed Mode, Drop-in Mode, and Routed Mode.

32. List the different types of Interface types supported by Firebox?

Different types of Interface types supported by Firebox are External, Trusted, Optional, VLAN, and custom.

33. What do you understand by Route?

A route is the distribution of devices through which network traffic is transferred. Each device in this sequence usually called a router, reserves information about the networks it is connected to inside a routing table.

34. What is the Precedence of schedules from highest to lowest?

Precedence of schedules from highest to lowest: Always, Recurring, Once, Daily, Weekly, Monthly.

35. What happens if the two policies do not match any other precedence criteria?

In the absence of any other determining factors, the Firebox device resorts to arranging policies in an ascending order based on their alphanumeric values. However, prior to this, it employs a dual criterion consisting of policy type and policy name. The policy type takes precedence over the name, ensuring that policies of the same type are grouped together. In cases where policies have the same type, the policy name is used to distinguish between them, as no two policies can share the same name and type. Consequently, this forms the final criteria for establishing policy precedence on the Firebox.

36. What can you do with HTTP-proxy filter?

HTTP-proxy filter allows you to monitor, control and secure the HTTP traffic in your network by inspecting and filtering HTTP requests and responses. You can block URLs, restrict access to certain sites, filter web content, and set policies to prevent data leaks and protect against malicious code.

37. Explain HTTPS client proxy action?

An HTTPS client proxy action defines settings for the investigation of outbound HTTPS requests. When you select the Inspect action in an HTTPS client proxy action, you select the HTTP client proxy action the HTTPS proxy uses to examine the content.

38. What do you understand by BOVPN Virtual Interfaces?

A BOVPN virtual interface describes a BOVPN tunnel that is used in the configuration like an interface. The Firebox uses the routes table to decide whether to route a packet through the BOVPN virtual interface or through another interface.

39. Is there any need to change the BOVPN tunnel route configuration?

There is no need to change the BOVPN tunnel route configuration when network changes are made on one or both sides of the BOVPN tunnel. This is particularly valuable if you have local networks that were learned through routers, and you want these networks to be accessible through the BOVPN.

40. What happens when Reputation Enabled Defense subscription expires?

Reputation Enabled Defense stops checking reputation immediately.
Reputation Enabled Defense configuration options are disabled in Policy Manager, except for the ability to disable Reputation Enabled Defense for a policy that has it enabled.
Lastly, Reputation Enabled Defense configuration options are disabled in Fireware Web UI.