OSI Model: In this course I had learned which is interesting because it plays a vital role in computing of all web browsers, sending and receiving information and opening a website. The page basically uses OSI MODEL model in which it is composed of seven layers Application layer, Presentation layer, Session layer, Transport layer, Network layer, Data link layer and physical layer From application layer to layer network are implemented by the end users while the last three are implemented by all nodes in the path. In the application layer the user interacts with the systems, this layer provides protocols in which applications communicate with each other, which means the application layer is our browser or our Gmail application if we send a mail. The Presentation layer is basically the operating system layer in which the application layer sends the information to the operation layer. Session layer deals with the communication creating the session between the two communications, which means this layer allows users from different machines to create a session between. The session layer can link all these different flows belonging to the same application. The transport layer receives data from the session layer and divides it into smaller units. This information is passed to the network layer on the receivers side and ensures that these messages are accepted and arranged in the correct order. The network layer divides messages into packets and transmits them across the network. This layer ensures that packets reach the correct destination. This is called routing. Data link layer in which switches operate and divides packets into smaller units called frames, these frames are passed to the physical layer for transmission...... middle of paper ...... ng for work is also a type of risk, it's good until we manage it, when we can't manage it, then there will be risk but it's convenient so we use it. When it comes to threats, I have been discussed in detail regarding Denial of Service, Unauthorized Access and many more. Let's come to the part of firewalls which will be useful in our personal life so that we can have the advantage of choosing the best one. We have come across types of firewalls and their benefits and which one is better. When it comes to secure devices, we had heard about callback systems, virtual private networks. As for attacks, I had heard about Trojans, software bugs and sniffers. Many businesses depend on the security of this network, such as online banking, business processes, etc. I also had an idea about hacking and how they do it. Everyone in the organization is responsible for security.