OSI Model: In this course I learned that it is interesting because it plays a vital role in the IT of all web browsers, sending and receiving information and opening a Web The page basically uses the OSI MODEL in which 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 network layer are implemented by the end users while the last three are implemented by all nodes of the path. In the application layer the user interacts with systems, this layer provides protocols where applications communicate with each other: the application layer is our browser or the Gmail application if we are sending an email. The presentation layer is basically the operating system layer where the application layer sends information to the operational layer. The Session layer takes care of the communication by creating the session between the two communications, which means this layer allows users of different machines to create a session between. The session layer can associate all these different flows that belong to the same application. The transport layer receives data from the session layer and divides it into smaller units and this information is passed to the network layer on the receivers and makes sure that these messages are accepted and organized in the correct order. The network layer breaks the message into packets and transmits them across the network, this layer takes care that the packets reach the correct destination. This is called routing. Data link layer where switches operate and breaks packets into smaller units called frames, these frames are passed to the physical layer for transmission... middle of paper... for work, this is also a type of risk it's good until we manage it, when we can't manage it then there will be a risk but it's convenient so we are using it. Coming to the threats I went into detail about denial of service, unauthorized access and much more. Coming 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 came across types of firewalls, their benefits and which one is best. Coming to secure devices, we learned about dial back systems and virtual private networks. Coming to the attacks I had learned about Trojan horses, software bugs, sniffers. There are many activities that depend on this network security such as online banking, business processes, etc. I also got an idea about hacking and how they hack. Everyone in the organization is responsible for security.