How the internet works, network protocols, and ports

In this section, we will start with the network models that are fundamental to the whole internet infrastructure. We will then dive deeper by explaining the protocol basics, as no data transfer can be realized without them.

TCP/IP and OSI network models

After reviewing the networking basics in the previous chapter (IP addresses, ping, DNS, listing a few protocols, etc.), let’s look at the overall networking model.

TCP/IP is an abbreviation of Transfer Control Protocol/Internet Protocol. It is the most widely applied network model and the current internet infrastructure base. You may have also heard of the Open Systems Interconnection (OSI) model. As OSI was introduced later, it was not directly and extensively applied, despite separating and presenting network communication better.

OSI has seven layers, each dedicated to a different functionality. Its upper layers are software (SW)-oriented, and the lower ones...