What is the Internet?

The Internet, often simply referred to as "the net," is a global network of interconnected computers and servers that allows devices worldwide to communicate and exchange information. It is a vast "network of networks" that operates using a standardized set of protocols known as the TCP/IP (Transmission Control Protocol/Internet Protocol).

Key Points:

  • Origins: The Internet's origins trace back to the 1960s when the U.S. Department of Defense initiated a project called ARPANET (Advanced Research Projects Agency Network) to allow multiple computers to communicate on a single network.

  • Functionality: At its core, the Internet facilitates the transmission of data between devices. This data can be in the form of websites, emails, multimedia (images, audio, and video), and more.

  • World Wide Web vs. Internet: It's essential to differentiate between the World Wide Web (WWW) and the Internet. The WWW is a subset of the Internet; it's a system of interlinked hypertext documents accessed via the Internet using web browsers.

  • Infrastructure: The Internet relies on a vast infrastructure, including physical hardware (like servers, routers, and data cables) and software protocols. Data centers around the world store the data we access, while ISPs (Internet Service Providers) help us connect to the Internet.

  • Decentralization: One of the Internet's defining characteristics is its decentralized nature. No single entity owns or controls it entirely. Instead, it's a collaborative effort with millions of devices contributing.

  • Impact: The Internet has revolutionized communication, commerce, entertainment, and education, breaking down geographical barriers and creating a truly global community.

What is DNS (Domain Name System)?

DNS, or Domain Name System, is a hierarchical and decentralized system that translates human-friendly domain names (like www.example.com) into IP addresses (like 192.0.2.1) that computers use to identify each other on the network. It functions as the "phonebook" of the Internet, allowing users to access websites using domain names instead of numeric IP addresses.

Key Points:

  • Purpose: The primary purpose of DNS is to convert easily remembered domain names into IP addresses, which are used for routing traffic across the Internet.

  • Hierarchy: DNS operates in a hierarchical fashion. At the top level, there are root servers, followed by top-level domains (TLDs) like .com, .org, and country-specific TLDs like .uk. Each TLD has its own set of authoritative name servers that store information about domains within that TLD.

  • Resolution Process: When you enter a URL into your browser, a DNS query is initiated. This query travels through a series of servers – from the local DNS resolver, to the root servers, and then to the authoritative name servers – to retrieve the corresponding IP address.

  • Caching: To speed up the resolution process, DNS responses are cached at multiple levels, including in your browser and at your ISP's DNS servers. This means that frequently accessed IP addresses can be retrieved faster without going through the entire DNS lookup process.

  • Security: DNS has evolved to include security measures like DNSSEC (DNS Security Extensions) to protect against malicious activities like cache poisoning and man-in-the-middle attacks.

  • Importance: DNS is a fundamental part of the Internet's infrastructure, ensuring that users can access websites and services using memorable domain names instead of having to remember numeric IP addresses.

HTTP and HTTPS Explained

HTTP (HyperText Transfer Protocol)

HTTP is the standard protocol used for transmitting web pages (consisting of text, images, and other resources) on the World Wide Web. It defines how messages are formatted and transmitted, and what actions web servers and browsers should take in response to various commands.

Key Points: - Stateless Protocol: Each request from a client to a server is treated as a new request, with no memory of past requests. - Port: By default, HTTP uses port 80 for communication. - Structure: An HTTP transaction consists of a request from a client (usually a web browser) and a response from the server (web server hosting the website). - Methods: Includes verbs like GET (retrieve data), POST (submit data), PUT (update data), DELETE (remove data), and more.

HTTPS (HyperText Transfer Protocol Secure)

HTTPS is the secure version of HTTP. It uses encryption to ensure that data transferred between the user's browser and the web server remains confidential and intact.

Key Points: - SSL/TLS: HTTPS uses SSL (Secure Sockets Layer) or its successor, TLS (Transport Layer Security), to encrypt the data packets that are sent and received. This encryption makes it difficult for eavesdroppers to understand the data even if they intercept it. - Port: By default, HTTPS uses port 443 for communication. - Security: Provides protection against man-in-the-middle attacks, eavesdropping, and tampering of data. - Certificate: Websites using HTTPS need to have a valid SSL/TLS certificate, which can be verified by Certificate Authorities (CAs). Browsers often show a padlock icon in the address bar for HTTPS-secured websites.

Why HTTPS Matters?

With the increasing threats to online security and privacy, using HTTPS has become essential. It ensures: - Data Integrity: Data cannot be modified or corrupted during transfer without being detected. - Confidentiality: Information remains private and is encrypted. - Authentication: Proves that users communicate with the intended website, building user trust.

Visit the following resources to learn more: 1. How does the Internet Work? 2. How the Internet Works in 5 Minutes 3. Everything you need to know about HTTP 4. HTTP/3 From A To Z: Core Concepts 5. Understanding Domain names