Internet Basics and Protocols

Internet Overview

• The internet is a global network of interconnected computers, established through collaboration and governed by standard protocols.
• No single entity owns the internet; it operates on a framework of shared rules.

Ways to Transfer Information

• Email Protocols: Utilize POP3, IMAP, and SMTP for sending and receiving messages.
• File Transfer: FTP (File Transfer Protocol) facilitates the transfer of files between computers.
• Secure Shell: SSH is employed for secure remote access to computers.
• World Wide Web: Enables access to linked documents through hypertext, creating an expansive network of information.

Protocols

• Protocols dictate standardized methods for data transfer across networks.

Web and Servers

• The World Wide Web connects documents via hypertext links.
• Web servers respond to requests for information, providing documents quickly.
• HTTP servers are a common designation for web servers.

Popular Web Server Software

• Apache: Open source software widely used for web servers.
• Microsoft Internet Information Services (IIS): A proprietary web server software from Microsoft.

IP Address and Domain Name System (DNS)

• Unique numeric IP addresses are assigned to every device on the internet.
• DNS translates domain names into IP addresses, making it easier for users to access servers.
• A single IP address can host multiple domain names, allowing shared resources.

Client and User Interaction

• Clients refer to software, such as desktop and mobile browsers, that send requests to servers.
• Browsers (also known as user agents) display retrieved documents to users.

HTTP Protocol

• HTTP serves as a transfer method for various web resources, including images, videos, audio files, and scripts.

Common Web Browsers

• Popular web browsers include:
  • Edge and Internet Explorer (Windows)
  • Google Chrome
  • Mozilla Firefox
  • Safari
  • Opera
  • Vivaldi

Rendering Engines

• Rendering engines convert HTML and CSS into visual representations on screens.
• Notable rendering engines include:
  • Blink: Used by Chrome 28+, forked from WebKit.
  • Gecko: Utilized by all Firefox versions (excluding iOS).
  • WebKit: Employed by Safari and Safari on iOS.
  • Trident: Used by Internet Explorer (versions 4-11).
  • EdgeHTML: Forked from Trident for Microsoft Edge.
  • Blink: Also used by Opera 15+.