Interview Preparation | Network Engineer - Part2

Network Security Interview Questions for Freshers
1. What is the internet?

Almost everyone uses the internet as their most important resource and tool. Internet connects millions of computers, webpages, websites, and servers. We may communicate with our loved ones via email, photos, videos, and messages via the internet. We may also share and get information online via the internet. When we have a device that is connected to the internet, we can use all of our applications, websites, social media apps, and more services. Sending and receiving information on the internet has become very fast in recent years.

2. What is a protocol?
A protocol is a set of rules that govern how two or more parties interact with each other. It is a way of specifying how data should be exchanged between two or more parties. Protocols are often used to control the flow of data, such as when sending emails or transferring files.

The most common type of protocol is the HTTP protocol, which defines how to exchange data between a web server and a web browser. HTTP is used by many websites to transfer data such as images, videos, and text.

3. What is pipelining?
Pipelining is a method of software development that involves writing and testing multiple versions of a software program at the same time. The process is similar to parallel processing, but it works on a more granular scale. Instead of writing one program, you write multiple programs that can run in parallel. The result is that you can write a new version of the program in just a few hours instead of weeks or months.

When you use pipelining, you write multiple versions of your software program at the same time. Each version is tested and developed separately. When all the programs are completed, the final version is run all at once.

4. What is the hub in networking?
Hubs are nodes in a network that is responsible for connecting other nodes. Hubs are often the first point of contact for new nodes, and they are also the first point of entry for external resources, such as software updates and customer service.

7. What are the factors that affect the performance of the network?
The performance of a network is dependent on a number of factors, including the quality of the hardware, the speed of the internet connection, and the amount of traffic that is being transferred. The speed of the internet connection is important because it affects how quickly data can be transferred. A high-speed connection can transfer data at a much higher rate than a low-speed connection.

The quality of the hardware also affects the performance of a network. Poorly-made hardware can cause problems with connectivity and performance. Finally, traffic can affect the performance of a network. If too much traffic is being transferred over a network, it can slow down the performance of the network. So, if you want to improve your network's performance, you should make sure that all of your equipment is up to date and that you are using the best possible internet connection.

8. What is LAN in networking?

Personal computers and workstations may share data, tools, and programs via a local area network. A switch or series of switches interconnects network devices so that computers and workstations may share data, tools, and programs. Private addressing is used in conjunction with the TCP/IP protocol to establish a local area network. A router connects the local area network to the wider internet.

The amount of data that can be transmitted at any given moment is limited by the number of computers connected, which means that the hardware (such as hubs, network adapters, and Ethernet cables) must be inexpensive and fast (i.e., hubs, network adapters, and Ethernet cables). Due to their small size, LANs (which are privately owned) cannot be used for much beyond an office building, home, hospital, school, etc. To build and maintain a LAN, twisted-pair cables and coaxial cables are typically used. The distance covered is also limited, so noise and error are minimized.

In the early days of LANs, data rates usually ranged from 4 to 16 Mbps. Today, 100 Mbps and 1000 Mbps speeds are more common. Because of the short path between computers in a LAN, the delay is very short. A LAN may be connected with up to thousands of PCs, even if wired connections are the primary means of communication. A LAN may include both wired and wireless connections to provide greater speed and security. A LAN can be more stable and have fewer congestion issues than a typical network. For example, in a single room where several Counter-Strike players are playing (without internet access).

9. What is WAN in networking?
WANs, also known as wide area networks, connect LANs over telephone lines and radio waves to form computer networks that cover a large area, even though they might be confined to a single country or state. Enterprises, governmental agencies, and other organizations may connect to WANs. WANs are fast and costly to operate.

WANs are difficult to design and maintain, with switched WAN and point-to-point WAN being the two types. A WAN is less fault-tolerant and has more congestion in the network than a MAN. Telephone lines or satellite links are used for communication. WANs are prone to long-distance noise and errors.

WAN data rates are slower than LAN data rates, because of the increased distance and increased number of servers and terminals involved, plus slower speeds. WAN speeds range from Kbps to Mbps, whereas LAN speeds typically range from Mbps to Gigabits per second (Gbps). The biggest obstacle is the propagation delay. Devices are utilised for WAN transmission in addition to Optic wires, microwave emissions, and satellites. Switched WANs include Asynchronous Transfer Mode (ATM) networks and Point-to-Point WANs, which connect a home computer to the Internet via a telephone line.

11. What is a network?

A network is a set of interconnected computers and other devices that allows information to flow between them. This is the process of connecting these devices and allowing them to communicate with each other. One of the most important aspects of networking is the ability to share data. The Internet is a huge network that allows people to share information and communicate with each other.

By sharing data, people can access information more efficiently and get it faster. Another important aspect of networking is security. Networking is a risky activity because there are many unknowns that can happen. For example, if someone hacks into your computer, you could lose all of your data. If someone steals your identity, you could be in trouble.

12. What is an intranet?

An intranet is a sort of closed network. It is used by a variety of firms and is accessible only by its employees. Intranets are networks that allow PCs from several corporations to communicate with each other. An intranet is a private network that allows access only by its members and employees. Many corporations and companies have their very own intranet networks, which are accessible to only their employees and clients. Because an intranet is a closed network, it does not pass information to the outside world and protects your data.

14. What is Application security in networking?

An application security program identifies, repairs, and eliminates vulnerabilities in applications within an organisation. Application security is all about finding, dealing with, and fixing vulnerabilities in applications. Application vulnerabilities that match with CWEs are identified and fixed. A weakness in the application is discovered and prevented from being exploited in the future.

15. What is Firewalls in networking?

A firewall monitors all incoming and outgoing traffic and matches a set of security rules to determine whether to accept, reject, or drop a packet.

When a rule is matched, an action is performed on the network traffic. For example, a firewall table might match network traffic against a rule specifying that employees from the HR department are forbidden from accessing data from a code server, and another rule may specify that system administrators are permitted to access both HR and technical data. A firewall can be designed to suit the organisation's security and efficiency needs by combining rules.

A firewall operates in two phases. It blocks both outgoing and incoming network connections. On the one hand, a firewall allows outgoing connections from a server. In this case, outgoing connections are permitted from a firewall's perspective. On the other hand, it is always best to set a firewall rule to block outgoing connections. This is because doing so will improve security and prevent unwanted communication. As mentioned above, ICMP messages are the most common type of incoming traffic. They have a source IP address and a destination IP address. Port numbers are also included in TCP and UDP communications. In the case of incoming ICMP packets, the type of message is used as opposed to a port number.

16. What is Network segmentation?

A subnet can be created by dividing a network into multiple segments or subnets, each of which acts as a separate little network. Controlled traffic flow between subnets is possible by using this architectural technique. In addition to improving monitoring, boosting performance, localizing technology problems, and most importantly, enhancing security, segmentation is employed by businesses.

Network security personnel have an effective tool in preventing important assets, such as customers’ personal information, corporate financial records and important intellectual property, from being exploited by malicious outsiders or curious insiders by means of network segmentation. These assets are frequently located in hybrid and multi-cloud environments, which have to be protected against hacking attempts. To know the security impact of segmentation, it is crucial to comprehend the nature of trust among network security.

17. What is Virtual Private Network?

A virtual private network (VPN) is a secure connection over an unsecure network, such as the internet. A VPN service creates a safe and encrypted connection across an insecure network like the internet. A VPN connects a private network with a public network like the internet to extend the network. The term “virtual private network” implies that the network is accessible by users sitting in the remote area. It uses tunneling protocols to create a secure connection.

Consider a scenario where a bank's corporate office is located in Washington, USA and uses a local network of 100 computers. Mumbai and Tokyo branch offices are used to connect with the head office using a leased line, a costly and time-consuming process. Using VPN, we can eradicate this challenge in a powerful way.

18. What is Web Security?

The security of a network or computer system is concerned with protecting it from damage or theft of software, hardware, or data. Computer systems are protected from misdirection or disruption of their services.

Website protection is known as web security and also includes cloud protection and web application security. It defends cloud services and web-based applications, respectively. A virtual private network (VPN) is also safeguarded.

To operate any business that uses computers, web security is critical. If a website is compromised or hackers can manipulate your software or systems, your website—and even your entire network—can be halted, resulting in business disruptions.

19. What is Wireless security?

Wireless networks provide several advantages to users, but they are really complicated to operate. Data packets travelling through wires provide users with the assurance that data sent through wire will unlikely be overheard by eavesdroppers.

We should focus on the following areas to ensure a secure wireless connection: Identifying the endpoint of the wireless network and the end users, protecting wireless data packets from middlemen, ensuring wireless data packets are intact, and keeping the wireless data packets anonymous.

All 802.11 wireless devices communicate with one another, regardless of their manufacturers. Whenever all wireless devices conform to the same standards, there is no problem. However, some rogue devices may be a danger to wireless security, as they may intercept our confidential data or cause the network to go down.

Switch:
A network switch (also called switching hub, bridging hub, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device.

Packet switching allows data to be sent over the telecommunications network in short bursts or "packets" that contain sequence numbers so that they can be reassembled at the destination.

A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches.

Router
A router is a device that forwards data packets between computer networks, typically by connecting a local network to the internet. It determines the best path for data to travel from the source to the destination

Layer: Layer: Operates at Layer 3 (Network Layer) of the OSI model.

A Router is a networking device that connects multiple networks, directing data traffic between them by finding the best path. While routers focus on connectivity and data routing.

Advantages of Using a Router

It connects multiple networks, enabling devices to share and communicate resources like files and printers, across many networks.
Uses algorithms like OSPF, BGP to find the most efficient paths for transmitting data , optimizes the network performance and reduces latency.
Routers help in the segmentation of networks, improving security and performance by isolating different parts of the network and it also reduces broadcast traffic.
Routers allow muti-device support to share a single internet connection making them essential for home and business networks.
NAT is used in routers to share a single public IP address , thus conserves IPv4 shortage.

Disadvantages of Using Routers

Configuring and setting up routers is complex for large scale network, it requires specialized knowledge.
Routers are vulnerable to attackes if they are not properly secured , such as using outdated firmware or misconfigurations.
In high traffic environments , routers perform bottlenecks if they lack sufficient processing power.
The cost of routers are high escpecially high performance routers which are used in large enterprises.

Source :
https://www.interviewbit.com/network-security-interview-questions/

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