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How does the Internet work?

The Internet, a global network of networks, is an incredibly complex system that involves many different components working together to provide global connectivity. Here's a detailed explanation of how it works:

  1. Devices and Local Networks: The journey of data on the Internet begins at a device such as a computer or smartphone. This device is connected to a local network - for example, your home Wi-Fi network. The device communicates with the router, which is connected to the Internet Service Provider (ISP) through a modem.

  2. Internet Service Providers (ISPs): ISPs are the entities that provide internet access to users. They have their own dedicated networks which are interconnected. When your device sends data, it goes through your router to your ISP, which then sends it on to its destination through a series of networks.

  3. IP Addresses: Every device connected to the internet has a unique IP address. This is a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. The IP address serves two main functions: identifying the host or network interface, and providing the location of the host in the network.

  4. Transmission Control Protocol (TCP): TCP is one of the main protocols in the Internet protocol suite. It's responsible for ensuring that the data sent from your device arrives at its destination without errors and in the correct order. TCP is like a courier by taking care of the entire communication process from data preparation to data transmission.

  5. Routing and Packet Switching: When data is sent over the internet, it's broken down into small pieces called packets. Each packet contains both the data being transmitted and the IP address of the destination. These packets take various routes to reach the destination. Routers along the way analyze the IP address on the packets and decide the next hop based on the routing table information. Once all the packets reach their destination, they are reassembled into the original data.

  6. Domain Name System (DNS): DNS is like the phone book of the internet. It translates human-friendly domain names into IP addresses that computers use to identify each other. When you type a URL into your browser, the DNS system translates that URL into the IP address of the web server hosting that site.

  7. HTTP and Web Browsers: HTTP (Hypertext Transfer Protocol) is the protocol used for transferring web pages over the internet. When you enter a URL in your web browser, the browser sends an HTTP request to the server hosting the website. The server then sends back the requested HTML page, which the browser renders and displays to the user.

  8. Servers and Hosting: Websites are hosted on servers, which are powerful computers that can handle multiple requests and send data to multiple users at the same time. When you access a website, you're actually connecting to a server somewhere that's sending you the website's files.

  9. Caching and CDNs: To speed up the delivery of web pages, the internet uses caching, where certain data is stored for quicker access in the future, and Content Delivery Networks (CDNs), which are geographically distributed networks of servers designed to provide faster delivery of internet content.

  10. Security and Encryption: To keep data secure as it travels across the internet, encryption is used. HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP, where data is encrypted before it's sent.

So, the internet is a complex system of interconnected devices and networks. When you access a website, you're sending a request through a series of networks to a server that sends back the data your browser displays as a web page. This all happens in just a few seconds, thanks to a series of protocols and systems working together.

HTTP

HTTP, or Hypertext Transfer Protocol, is the foundation of any data exchange on the Web. It's a protocol used for transmitting hypermedia documents, such as HTML. It follows a client-server model where the client opens a connection to make a request, then waits until it receives a response from the server. The server processes the request and sends a response back to the client. The client then closes the connection.

Here's a more detailed explanation:

  1. HTTP and Browsers: When you enter a URL in your web browser, the browser sends an HTTP request to the server hosting the website. This request includes the method (like GET, POST, PUT, DELETE, etc.), the headers (which provide information about the request), and sometimes a body (which includes the actual data to be sent, like form data).

  2. HTTP Methods: HTTP defines a set of request methods to indicate the desired action to be performed for a given resource. The most common methods are GET (retrieve a resource), POST (send data to the server), PUT (update a resource), and DELETE (remove a resource).

  3. HTTP Headers: HTTP headers let the client and the server pass additional information with an HTTP request or response. Headers are colon-separated name-value pairs in clear-text string format. They define aspects of the data being sent, like its encoding, language, format, how it should be cached, and more.

  4. HTTP Response: The server processes the request and sends back an HTTP response. This response includes a status code, headers, and a body, which is the actual content being returned (like the HTML of a web page). The status code tells the client whether the request was successful or not, and provides additional information about the result of the request.

  5. HTTP Status Codes: HTTP response status codes indicate whether a specific HTTP request has been successfully completed. They are divided into five classes: informational responses (1xx), successful responses (2xx), redirection messages (3xx), client error responses (4xx), and server error responses (5xx).

  6. Stateless Protocol: HTTP is a stateless protocol, which means that each request from a client to a server is treated as a new, standalone request. The server does not store any information about the client between requests. This is why websites use cookies to remember users, because HTTP itself does not have a built-in mechanism for remembering previous requests.

  7. HTTP vs HTTPS: HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP, where data is encrypted before it's sent. This is done using SSL (Secure Sockets Layer) or TLS (Transport Layer Security) protocols. This ensures that the data cannot be read by anyone else, even if they manage to intercept it.

HTTP is a protocol that allows the fetching of resources, such as HTML documents. It is the foundation of any data exchange on the Web and it's a protocol used for transmitting web pages. It follows a client-server model and is stateless, meaning each request is treated as an independent transaction that is unrelated to any previous request.

Domain name

A domain name is a human-friendly address, sometimes called a URL (Uniform Resource Locator), that people use to visit websites. It's the name that you type into a web browser's address bar to visit a specific website. For example, "www.example.com" is a domain name.

Here's a list of the most important things to know about domain names:

  1. Purpose of Domain Names: The primary purpose of domain names is to provide easy-to-remember and usable addresses for websites, as opposed to using the IP addresses that computers use to identify each other. Remembering "www.example.com" is much easier than remembering "192.0.2.0".

  2. Structure of Domain Names: A domain name consists of two main parts: the domain name itself and the domain extension or TLD (Top-Level Domain). In "www.example.com", "example" is the domain name, and ".com" is the TLD. The "www" is a subdomain, used to specify a particular part of a website.

  3. Top-Level Domains (TLDs): TLDs are the highest level of domain names in the root zone of the DNS (Domain Name System). They are divided into generic TLDs (like .com, .net, .org, .edu), country-code TLDs (like .us, .uk, .ca), and more recently, brand TLDs (like .google, .amazon).

  4. Domain Name System (DNS): The DNS is like the phone book of the internet. It translates human-friendly domain names into IP addresses that computers use to identify each other. When you type a URL into your browser, the DNS system translates that URL into the IP address of the web server hosting that site.

  5. Domain Name Registration: To use a domain name, you must register it with a domain name registrar. This is usually a paid service. When you register a domain name, you gain the exclusive rights to use that name for a set period, usually a year, with the option to renew.

  6. Domain Name Servers: Domain Name Servers (DNS) are the internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses. This is necessary because, although domain names are easy for people to remember, computers or machines access websites based on IP addresses.

  7. Subdomains: Subdomains are extensions of your domain name that you can forward to URLs or point to IP addresses and directories within your hosting account. For example, in the URL "blog.example.com", "blog" is a subdomain.

  8. Domain Name Privacy: When you register a domain name, your personal information is published in a public directory called WHOIS. Many registrars offer domain privacy services to keep your information private and replace it with their own.

What is Web Hoisting?

Web hosting is a service that allows organizations and individuals to post a website or web page onto the Internet. A web host, or web hosting service provider, is a business that provides the technologies and services needed for the website or webpage to be viewed on the Internet. Websites are hosted, or stored, on special computers called servers.

Here's a list of the most important things to know about web hosting and how it works:

  1. Servers: Websites are hosted on servers, which are powerful computers that can handle multiple requests and send data to multiple users at the same time. When you access a website, you're actually connecting to a server somewhere that's sending you the website's files.

  2. Types of Web Hosting: There are several types of web hosting services available, including shared hosting (where multiple websites share the same server), dedicated hosting (where a website has its own server), VPS hosting (which is a middle ground between shared and dedicated), and cloud hosting (which uses multiple servers to balance the load and maximize uptime).

  3. Domain Names and Web Hosting: When you sign up for a web hosting service, you'll usually also get a domain name, which is the address that people type into their browser to access your website. The web host is responsible for directing those requests to the correct server.

  4. Web Hosting Services: Web hosting services usually include more than just server space. They also typically include email hosting, storage and bandwidth management, security features like SSL certificates, customer support, and tools to build and manage your website.

  5. CMS and Web Hosting: Many web hosts also support content management systems (CMS) like WordPress, which make it easy to build and manage a website without needing to know how to code.

What is a DNS?

DNS, or Domain Name System, is a decentralized and hierarchical naming system for computers, services, or other resources connected to the Internet or a private network. It translates human-friendly domain names into the numerical IP addresses needed for locating and identifying computer services and devices.

Here's a list of the most important things to know about DNS:

  1. Purpose of DNS: The primary purpose of DNS is to convert human-friendly domain names like "www.example.com" into IP addresses like "192.0.2.0" that computers use to identify each other on the network. It's like the phone book of the internet.

  2. DNS Hierarchy: DNS follows a hierarchical structure. At the top level, there are root servers that know the IP addresses for all the Top-Level Domain (TLD) servers, which in turn know the IP addresses for the second-level domain servers, and so on. This hierarchy allows the system to scale and ensures that domain names are unique.

  3. DNS Lookup: When you type a URL into your browser, your computer performs a DNS lookup to find the IP address associated with that domain name. This process involves querying multiple DNS servers, starting from the root, then the TLD server, and finally the authoritative DNS server for the specific domain.

  4. DNS Caching: To speed up the process of DNS lookup, IP addresses are often stored or "cached" on a local machine or within the network. When a DNS lookup is requested, the system first checks the cache to see if the domain name is already associated with an IP address.

  5. DNS Records: DNS servers store records about their domain names. The most common type of DNS record is an "A" record, which maps a domain name to an IP address. Other types of records include "CNAME" records (which map a domain name to another domain name), "MX" records (which specify the mail servers used by the domain), and "NS" records (which specify the DNS servers used by the domain).

  6. DNS Servers: There are several types of DNS servers. Recursive resolvers are the servers that receive query requests from clients and communicate with other servers to find the answer. Root servers respond to initial requests in a DNS lookup. TLD servers host the last portion of a domain name (like .com or .org). Authoritative servers host DNS records for specific domain names.

  7. DNS Security: DNS has several security features. DNSSEC (DNS Security Extensions) provides authentication and integrity to the DNS. DNS over HTTPS (DoH) and DNS over TLS (DoT) provide privacy by encrypting DNS queries.

DNS is a critical component of the internet infrastructure that translates human-friendly domain names into IP addresses. It follows a hierarchical structure, uses caching to improve performance, and includes several types of records and servers. It also has features to ensure the security and privacy of DNS queries.

What is a browser and how it works?

Web browsers are software applications that allow users to retrieve, present, and traverse information resources on the World Wide Web. They interpret and render HTML, the code that websites are structured in, along with CSS and JavaScript.

Here's a more detailed explanation:

  1. User Interface: This includes the address bar, back and forward buttons, bookmarking menu, etc. Every part of the browser display except the window where you see the requested page.

  2. Browser Engine: This marshals actions between the UI and the rendering engine.

  3. Rendering Engine: This is responsible for displaying the requested content. For example, if the requested content is HTML, it is responsible for parsing the HTML and CSS and displaying the parsed content on the screen.

  4. Networking: This is for network calls, like HTTP requests. It uses different implementations for different platform behind a platform-independent interface.

  5. UI Backend: This is used for drawing basic widgets like combo boxes and windows. It exposes a generic interface that is not platform-specific. Underneath it uses operating system user interface methods.

  6. JavaScript Interpreter: This is used to parse and execute JavaScript code.

  7. Data Storage: This is a persistence layer. Browsers may need to save all sorts of data locally, such as cookies. Browsers also support storage mechanisms such as localStorage, IndexedDB, WebSQL and FileSystem.

Here's how the process works:

  1. URL Input: The process starts when you type a URL into the browser.

  2. HTTP Request: The browser sends an HTTP request to the server where the website lives. The server then sends back an HTTP response.

  3. Page Rendering: The browser begins rendering the page using the rendering engine. It parses the HTML and CSS of the page, and displays the page on the screen.

  4. Interactive Elements: If the page has any JavaScript, the browser interprets and executes it, which may manipulate the HTML of the page.

  5. Finished Loading: Once the page has finished loading, the browser sends an HTTP request for each resource that the page has linked to, such as images, videos, or other pages. This is done asynchronously, meaning it happens alongside other tasks.

  6. User Interaction: The user can now interact with the page. They can click links, fill out forms, or use any other interactive elements the page has.

  7. Closing the Page: When the user is done with the page, they can close it. The browser then frees up the memory that was used to store the page.

A web browser is a complex piece of software that plays a crucial role in the web ecosystem. It takes a URL, sends an HTTP request, receives an HTTP response, and then renders and displays the page while handling any interactive elements. It also manages data storage and user interaction.