Module-4 Internet & E-mail PDF

Module-4 Internet & E-mail Brainware University  Brief Idea & History The Internet is a global network of interconnected computers and devices, enabling users to share and access information. It facilitates communication through various services, such as email, web browsing, f...

Module-4 Internet & E-mail Brainware University  Brief Idea & History The Internet is a global network of interconnected computers and devices, enabling users to share and access information. It facilitates communication through various services, such as email, web browsing, file sharing. 1960s – ARPANET: The Internet's foundation was laid in the 1960s with the creation of ARPANET (Advanced Research Projects Agency Network) by the U.S. Department of Defense. ARPANET was designed to share resources between computers across long distances. In 1969, it connected four major Universities in the U.S. Brainware University 1970s – Birth of TCP/IP: Transmission Control Protocol/Internet Protocol (TCP/IP), developed by Vint Cerf and Bob Kahn, became the standard Com. protocol, enabling different networks to interconnect. 1973, ARPANET went international, connecting to n/w in Europe. 1980s – Domain Name System (DNS) and Growth: 1983, the Domain Name System (DNS) was introduced, allowing easier identification of websites using names instead of numerical addresses (e.g.,.com,.edu). Universities and research institutions began connecting to ARPANET. 1990s – The World Wide Web In 1991, Tim Berners-Lee invented the World Wide Web (WWW), which revolutionized the way people accessed information on the Internet. Web browsers like Netscape Navigator and Mosaic were developed, making the Internet more accessible. By the mid-1990s, the Internet became commercialized, with businesses and individuals using it widely. Brainware University 1 2000s to Present – Expansion and Modern Internet: The rise of broadband connections, wireless networks, and mobile devices has transformed the Internet into a highly integrated part of everyday life. Web 2.0 emerged, focusing on user-generated content, social media, and interactive platforms (e.g., Facebook, YouTube). Today, the Internet powers communication, entertainment, business, and the Internet of Things (IoT). Brainware University  Network Devices Network devices play a crucial role in connecting Computers and enabling data communication across networks. Router: A router directs data packets between networks, ensuring they reach the correct destination. It connects different networks, such as a local network to the Internet. Switch: A switch connects devices within a local area network (LAN) by forwarding data to the correct device. It operates at the data link layer (Layer 2) of the OSI model. Brainware University  Network Devices Hub: A hub is a basic networking device that broadcasts data to all connected devices in a network. It's less efficient than a switch, as it doesn't filter or direct data to specific devices. Modem: A modem (modulator-demodulator) converts digital data into analog signals and vice versa, allowing devices to connect to the Internet through telephone lines or cable systems. Brainware University  Network Devices Access Point (AP): An AP enables wireless devices to connect to a wired network, creating a wireless local area network (WLAN). It's commonly used in Wi-Fi networks. Firewall: A firewall is a security device that monitors and controls incoming and outgoing network traffic based on security rules, helping to protect a network from unauthorized access. Brainware University  Protocols Network protocols are rules and standards that enable devices to communicate on a network. Transmission Control Protocol/Internet Protocol (TCP/IP): TCP/IP is the foundational suite of protocols for the Internet. TCP ensures reliable data transfer, while IP is responsible for routing packets to their destination. Brainware University  Protocols Hypertext Transfer Protocol (HTTP/HTTPS): HTTP is used to transfer web pages from a server to a user's browser. HTTPS is the secure version, encrypting the data for security. File Transfer Protocol (FTP): FTP is used to transfer files between a client and a server over a network. It’s commonly used for uploading and downloading files. Brainware University Simple Mail Transfer Protocol (SMTP): SMTP is used for sending emails between servers, and it ensures reliable email delivery across the Internet. Post Office Protocol (POP) and Internet Message Access Protocol (IMAP): POP and IMAP are protocols used for retrieving emails from a server to a client. POP downloads the emails, while IMAP synchronizes them between the client and the server. Dynamic Host Configuration Protocol (DHCP): DHCP assigns IP addresses to devices on a network automatically, eliminating the need for manual configuration. Domain Name System (DNS): DNS translates human-readable domain names (e.g., www.google.com) into IP addresses, allowing users to access websites using easy-to-remember names. Secure Shell (SSH): SSH is a protocol used to securely connect to remote devices over an encrypted connection, commonly used for remote administration of servers. Brainware University  Web Browser A web browser is a software application that allows users to access, retrieve, and view information on the Internet. It acts as a gateway to the World Wide Web, interpreting and displaying web pages, multimedia, and other internet resources using various protocols like HTTP and HTTPS. Common Features of Web Browsers: Address Bar: Users can enter the URL (Uniform Resource Locator) of a website to visit specific pages. Navigation Buttons: Includes "Back," "Forward," "Refresh," and "Home" buttons for easy navigation. Brainware University Bookmarks/Favorites: Allows users to save and organize frequently visited websites. Tabs: Users can open multiple web pages in a single window, making it easier to multitask. Download Manager: Handles the download of files from the web. Privacy and Security Features: Includes settings like "Private/Incognito Mode" for secure browsing and cookies management. Brainware University Popular Web Browsers: Google Chrome: Fast and widely used, developed by Google. Mozilla Firefox: Open-source browser known for privacy and customization. Microsoft Edge: Microsoft's modern browser built on the Chromium engine. Safari: Apple's web browser optimized for macOS and iOS. Opera: Known for its integrated VPN and ad blocker. Brainware University  Introduction to Email Email (Electronic Mail) is a method of exchanging digital messages over the Internet. It is one of the most widely used communication tools, enabling users to send messages, documents, images, and other attachments to one or more recipients. Components of an Email: Email Address: A unique identifier for the sender and recipient, typically in the format [email protected]. Username: The identifier for the person or entity (e.g., john.doe). Domain: The server hosting the email service (e.g., gmail.com or outlook.com). Brainware University Subject Line: A brief description of the content or purpose of the email. Body: The main content of the email. It can include text, images, and hyperlinks. Attachments: Files (documents, images, PDFs, etc.) that can be sent along with the email message. CC (Carbon Copy): Sends a copy of the email to additional recipients without concealing the email addresses. BCC (Blind Carbon Copy): Sends a copy to additional recipients but conceals their email addresses from the main recipient. Brainware University Brainware University  Working Procedure of Email The process of sending and receiving emails involves a series of steps and multiple servers that work together. 1. Composing and Sending the E-mail: The user composes an email using an email client (like Gmail, Outlook, or Thunderbird) and clicks "Send." The client connects to the Simple Mail Transfer Protocol (SMTP) server of the sender's email provider. This server is responsible for sending emails. 2. E-mail Transmission: The email is forwarded from the sender’s SMTP server to the recipient’s Mail Transfer Agent (MTA). If the recipient's server is not the same as the sender's, the email is relayed over the Internet through multiple servers until it reaches the recipient’s server. Brainware University  Working Procedure of Email 3. E-mail Reception: Once the email reaches the recipient’s email server, it is stored there until the recipient is ready to retrieve it. Commonly used protocols for retrieving emails from the server include: Post Office Protocol (POP3): Downloads the email from the server to the recipient’s device and usually deletes it from the server. Internet Message Access Protocol (IMAP): Synchronizes emails between the server and multiple devices, allowing the user to access their email from various devices without deleting the original emails from the server. Brainware University  Working Procedure of Email 4. Reading the E-mail: The recipient uses their email client to access their email server. Using the IMAP or POP3 protocol, the email client retrieves and displays the email for the recipient to read. With IMAP, the emails remain on the server and are accessible from any device, whereas with POP3, emails are usually stored locally after being downloaded. Diagram: Working of E-mail System Brainware University  Protocols Involved in E-mail SMTP (Simple Mail Transfer Protocol): Used for sending emails. The sender’s email client communicates with the SMTP server to deliver the email to the recipient’s mail server. IMAP (Internet Message Access Protocol): Used for retrieving emails while keeping them on the server. This protocol enables syncing emails across multiple devices. POP3 (Post Office Protocol version 3): Used for downloading emails from the server to the client’s local machine, typically removing them from the server afterward. Brainware University Thank you Brainware University