Understanding the Internet and Its Services

The Internet

• A worldwide network connecting thousands of smaller networks.
• A global system with billions of devices linked by the internet protocol suite (TCP/IP).
• Composed of millions of networks connected by different technologies.
• AKA The Net, Info.Superhighway, Cyberspace.

Intranet vs. Extranet

• Intranets use the internet, but only for internal use within organisations.
• Extranets are similar to intranets but allow use by certain external entities, like suppliers.

Internet Services and Uses

• Email and Discussion Groups - Communicate with individuals and groups
• Research and Information - Access vast knowledge resources.
• News - Stay updated on current affairs
• Entertainment - Access multimedia content like videos and music.
• File Downloading - Download documents or files.
• E-Shopping - Purchase goods online.
• Finacial Matters - Manage finances and online banking.
• Online Auctions - Bid on items online.
• Career Advancement - Seek opportunities and apply for jobs.
• E-Business - Conduct business operations online.
• Social Networking - Connect with friends and family.

World Wide Web (WWW)

• An interconnected system of internet computers (servers) that support various documents in multimedia format.
• Built on the internet and provides a way of accessing information over the internet.
• Not the same as the internet.

Useful Concepts

• Hypertext is text with references (hyperlinks) to other text.
• Hyperlink is a reference to data that the reader can follow by clicking or hovering.
• Hypertext Markup Language (HTML) is a language used to create documents on the World Wide Web.

Web Browser

• Software used for retrieving, presenting, and accessing information on the World Wide Web.
• Uses a client-server model.
• Browser is the client and communicates with the web server to request information.
• Web server responds to the request and sends information back to the browser.

Examples of Web Browsers

• Most popular: Microsoft Edge and Mozilla Firefox
• Others: Google Chrome, Apple Safari, and Opera.
• Used to access information within private networks like intranets.

Mobile Browsers

• Designed for accessing the web from mobile devices.
• Smaller versions of web browsers with fewer features to run efficiently.
• Optimized for smaller screens and limited processing power.

Webpages vs. Websites

• Webpage is a document written in HTML that is accessible through the Internet or a network.
• Website is a collection of one or more webpages grouped under a domain name.
• Both are accessed using a Uniform Resource Locator (URL).

Uniform Resource Locator (URL)

• A global address of documents and other resources on the World Wide Web.
• Three parts:
  • Network protocol (e.g., http://)
  • Host name or address (the domain name)
  • File or resource location (the specific resource).

Static Webpages

• Delivered exactly as stored.
• Provide the same information to all users at all times.
• Usually ".html" files.
• Easy to create and don't require special web servers (e.g., a student's personal profile page).

Dynamic Webpages

• Prepared with content or layout based on certain criteria.
• Information frequently changes (e.g., stock prices).
• Utilize client-side and server-side scripting languages (e.g., JavaScript, ASP, PHP).
• Example: An online store showing different prices, reviews, and user information.

HyperText Transfer Protocol (HTTP)

• A protocol used for viewing webpages on the web.
• The foundation of data communication for the World Wide Web.

File Transfer Protocol (FTP)

• A protocol used to transfer files from one host to another over a network.
• Based on client-server architecture.

Internet Security Protocols

• HTTPS (HTTP Secure): Encrypts data being retrieved by HTTP.
• Secure Socket Layer (SSL): A standard protocol for establishing encrypted links between servers and clients.
• Transport Layer Security (TLS): The successor to SSL and the latest standard for secure communication.
• Advanced Encryption Standard (AES): An encryption algorithm for securing sensitive data over the internet.

Firewall

• A system designed to prevent unauthorized access to or from a private network.
• Commonly used to prevent unauthorized internet users from accessing internal networks.
• Examines all messages entering or leaving the intranet and blocks those that don't meet security criteria.

Search Engines

• Systems or websites designed to search for information on the World Wide Web.
• Present results in a list or search engine results pages (SERPs).

Examples of Search Engines

• Google
• Bing
• Yahoo
• DuckDuckGo
• Baidu

Email Services

• Electronic mail, commonly referred to as email or e-mail.
• First email sent in 1971 by Ray Tomlinson to himself.

Email Addresses

• Gmail.com
• Yahoo.com
• Hotmail.com
• MySpace.com
• Fastmail.com
• Mail.com
• Fanbox.com

Composing an Email

• TO: List of addresses of intended recipients.
• CC: List of addresses for those receiving a copy of the message. They can see original recipients.
• BCC: List of addresses for those receiving a blind copy. They cannot see other recipients.
• SUBJECT: Message title that appears in the recipient's inbox.

Email Parts

• Subject: Message title
• From: Sender's email address
• To: List of recipient addresses
• CC: List of carbon copy recipients
• BCC: Blind copy recipients
• Date: Date and time of the email.
• Body: Content of the message.

Questions

• This section is for possible questions or prompts to engage with the material. The text itself does not contain actual questions.