Network (v-lan, segmentation, firewalls, monitoring)

Question 1

What is the OSI-Model?

Answer 1

1. It is a conceptual framework that describes how network protocols communicate with each other.
2. It consists of 7 layers that represent different functions and protocols in the process of transmitting data across a network.

Question 2

Name the 7 layers in the OSI-Model.

Answer 2

1. Physical Layer.
2. Data Link Layer.
3. Network Layer.
4. Transport Layer.
5. Session Layer.
6. Presentation Layer.
7. Application Layer.

Question 3

What does the physical layer do?

Answer 3

It deals with the physical connection between devices and the transmission of raw data

Question 4

What does the data link layer do?

Answer 4

It provides reliable data transmission across the physical link, error detection, and correction

Question 5

What does the network layer do?

Answer 5

It manages the movement of packets across the network, routing, and congestion control.

Question 6

What does the transport layer do?

Answer 6

It ensures reliable and orderly delivery of data between endpoints, handling flow control and error recovery

Question 7

What does the session layer do?

Answer 7

It provides for the establishment and management of connections between applications

Question 8

What does the presentation layer do?

Answer 8

It deals with the representation of data and the conversion of data into a suitable format for transmission

Question 9

What does the application layer do?

Answer 9

It provides services to end-user applications, such as email, file transfer, and web browsing.

Question 10

In reference to the OSI-model, what does it mean when each layer only ‘see’ the corresponding layer?

Answer 10

Each layer only interacts with the layer immediately above it and the layer immediately below it.

This means that each layer has a specific role and responsibility and communicates only with its adjacent layers, which helps to ensure that data is transmitted accurately and efficiently.

Question 11

What is TCP/IP?

Answer 11

It is a set of communication protocols that are used to connect devices on the internet.

2. It provides end-to-end communication across networks, and is responsible for transmitting data packets from one device to another.

Question 12

What is the importance of TCP/IP in the OSI-model?

Answer 12

1. It provides the underlying foundation for network communication and it maps to some of the layers in the OSI model.
2. TCP/IP defines how data is sent over a network, while the OSI model provides a conceptual framework for understanding how different network protocols and technologies interact with each other.

Question 13

What is UDP?

Answer 13

It is a communication protocol used in computer networks that allows for fast data transmission without error-checking or resending lost packets.

It’s often used for real-time applications such as video conferencing, online gaming, and live streaming where speed is more important than reliability.

Question 14

what is ICMP?

Answer 14

It is a protocol used in computer networks to send error messages and operational information about the network.

It is typically used for diagnostics such as the ‘Ping’ service.

Question 15

What are cables?

Answer 15

They are used to physically connect devices in a network, allowing them to communicate with each other.

Question 16

What are NIC’s/network cards?

Answer 16

They are hardware components that are installed on computers to provide them with network connectivity.

They allow computers to send and receive data over a network.

Question 17

What are hubs?

Answer 17

They are devices that allow multiple devices to be connected to a network.

They work by broadcasting data to all connected devices, regardless of whether the data is intended for that device or not.

Question 18

What are switches?

Answer 18

They are similar to hubs in that they allow multiple devices to be connected to a network, but they are more intelligent.

They use a process called “switching” to direct data only to the device it is intended for, increasing network efficiency and security.

Question 19

What are routers?

Answer 19

They are devices that connect multiple networks together and allow data to be transmitted between them.

Question 20

What are Vlan’s?

Answer 20

They are a way to create multiple virtual networks within a single physical network.
This allows network administrators to group devices into separate networks for better security and easier management.

Question 21

What is an IP-address?

Answer 21

It is a unique identifier assigned to every device connected to a network.

Question 22

What is a network mask?

Answer 22

It is a set of numbers that is used to identify which part of an IP address is for the network and which part is for the host.

It helps to determine which devices are on the same network.

Question 23

What is a gateway?

Answer 23

It is a device or a computer program that connects two or more networks and forwards packets between them.

Question 24

What is a subnet mask?

Answer 24

It is a number that determines how many bits of an IP address represent the network part and how many represent the host part.

It is used to divide a large network into smaller subnetworks, which can help manage network traffic and improve network performance.

Question 25

Which ports are the most important to remember in this course?

Answer 25

1. 22 (SSH).
2. 80 (HTTP).
3. 3306 (MySQL).
4. ???

Question 26

What is DNS?

Answer 26

It is a system that translates domain names (such as www.example.com) into IP addresses that computers use to identify each other on the internet.

Question 27

What is the DHCP server?

Answer 27

It is a network protocol that automatically assigns IP-addresses and other network configuration parameters to devices on a network.

It is responsible for managing and assigning IP addresses to devices that request them, eliminating the need for manual IP configuration.

Question 28

what is a firewall and which layers in the osi model does the firewall operate?

Answer 28

1. It is a security device that monitors and controls incoming and outgoing network traffic based on an organization’s previously established security policies.
2. It operates at the Network layer (Layer 3) and Transport layer (Layer 4).

Question 29

What is the firewall’s purpose in the two layers?

Answer 29

Layer 3: It can inspect IP addresses, packet headers, and port numbers to determine whether to allow or block traffic.

Layer 4: It can inspect the contents of the packet payload to determine whether to allow or block traffic.

Question 30

What is a firewall rule?

Answer 30

1. It is a specific instruction that determines how incoming or outgoing network traffic should be handled.
2. Each rule is typically composed of several parts, such as the source and destination IP addresses, ports, and protocols.

Example: A rule might be created to allow traffic from a specific IP address to a specific port on a server, while another rule might block traffic from a known malicious IP address

Question 31

Can firewall rules protects us from SQL-injections and Smurf attacks?

Answer 31

Yes, a properly configured firewall can help protect against SQL injection and Smurf attacks by blocking unauthorized traffic and preventing malicious packets from reaching their intended target.

Question 32

What is IDS?

Answer 32

It is a passive security system that monitors network traffic and analyzes it for signs of unauthorized access, attacks, or other security threats.

It can detect and alert the network administrator when suspicious activities are detected, but it does not take any action to stop the attack.

Question 33

What is IPS?

Answer 33

It is an active security system that not only monitors network traffic but also takes actions to prevent attacks. When a potential security threat is detected, IPS can block the suspicious traffic, modify it, or terminate the connection.

Question 34

What is Onion security?

Answer 34

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Question 35

What is a honey pot?

Answer 35

It is a decoy system designed to look attractive to attackers, but actually, it is isolated and monitored to gather information about the attacker’s behavior and methods.

Question 36

What are honey pots used for?

Answer 36

They are used to detect and learn about new threats or attack techniques, which can then be used to improve the security of the real systems.

Question 37

What are phony users?

Answer 37

These are computer-generated user accounts that are created for specific purposes, such as testing or security.

Question 38

Which steps do you go through to set up a network for internal security?

Answer 38

1. You use local IP-ranges.
2. NAT.
3. You segment the network.
4. You audit the log and monitor.

Question 39

What is NAT?

Answer 39

It is a technique used in computer networking to allow devices on a private network to communicate with the Internet.

Question 40

How does NAT work?

Answer 40

It works by translating private IP addresses into public IP addresses that can be used on the Internet. This allows multiple devices to share a single public IP address and can provide an additional layer of security by hiding the private IP addresses from the public network.

Question 41

How do you segment your network by using Vlan’s?

Answer 41

1. Use switches you can administer remotely from one platform rather than visiting all patchpanel in the building
2. By using vlan you can design network zones freely without respecting the phyical cabling.
3. By making zones we protect vital traffic and make sure confidential traffic isn’t broadcasted.