Basics of networking

Let's define the basic terms related to computer networks:

Computer network - A collection of devices, such as computers, printers, telephones and televisions, that are linked together to exchange data. A transmission medium is used to connect the devices and a communication protocol is used to transmit the data.

IPv4 Address - This is a 32-bit number, entered in decimal form for ease of use (e.g. 192.168.31.190), used to identify devices and address data on the network.

HOST - This is a device with an IP address that is the source or recipient of data transmitted over the network, i.e. it receives data from other devices or sends such data. The term host is sometimes used interchangeably with the term terminal, as it usually refers to a computer, tablet or smartphone, i.e. a device with which the network user has direct contact.

Client - The device, or more specifically its software, uses the services provided by the server. The most common client today is the web browser, which allows the content of web pages hosted by a web server to be viewed. Other examples of clients are FileZilla, which allows files to be exchanged over the Internet, and all sorts of email software, which makes it easier to use email. Game consoles or smart phones are also clients, as long as they are connected to the internet.

Server - This is a computer that has special software installed to provide services to other computers. The service that a server can provide is, for example, a website, email or file resource. A server can be any computer that has software installed and configured on it, such as APACHE, which is used to maintain and share websites, or MySQL, which is a database management system. A server is usually a dedicated computer with high processing power that can handle multiple connections and requests simultaneously.

Transmission Medium - In other words, the medium that is the network element through which devices communicate and exchange data. This medium can be copper wire, fibre or radio waves (WiFi).

Communications Protocol - This is the method or language of communication and data exchange between devices that defines the rules and principles of that communication.

Internet - A set of interconnected wide area networks that form a global computer network. The origins of the Internet can be traced back to the creation of the ARPANET network in the late 1960s, and the first Internet connection in Poland was launched in September 1990. The Internet is seen by many as a collection of websites to browse, but this is not the case, as the Internet is a collection of many large networks spread around the world, and websites are specific network services.

Intranet - This is a private internal network that uses exactly the same communication standards (protocols) as the Internet, but is only accessible to authorised users, such as employees of a particular company. In most cases, access to an intranet or internal company network is via a website, so communication is said to use the same standards as the Internet.

Extranet - is a wide variety of intranets that allow access to its resources not only to the employees of a particular company, but also to other users.

DNS (Domain Name System) - A network service that translates a human-readable name, called a mnemonic name, into the IP address of a device on the network. It is a basic service of the Internet that changes the addresses of websites to the corresponding IP addresses of the servers where these websites are stored, e.g. changing the Internet address onet.pl to the IP address 214.180.141.140.

DHCP (Dynamic Host Configuration Protocol) is an automatic configuration protocol that assigns an IP address, subnet mask or default gateway address to a host. It is the most common method of assigning IP addresses to computers on a network, as it does not require manual IP address configuration on each computer.