Lesson 1

When you are surfing the Web , your most important goal is to get what you want. There are a variety of Internet services and tools that enable users to surf, find, and access resources on the Internet. You might call these search services and tools clients. Most of the terms and concepts are very familiar. You only have to pick up any new media magazine and chances are you will find them. They are really at the heart of Internet use, and now you can explore how to apply them.
This module will help you

1. Explain the purpose of HTTP
2. Define email communication
3. Explain the purpose of FTP
4. Describe Telnet
5. Describe the USENET
6. Describe the role of LISTSERV
7. Explain how to use Internet Relay Chat (IRC)
8. Evaluate Web browsers
9. Explore search engines and best practice techniques for searching

The HTTP, SMTP, and FTP protocols each play distinct roles in providing internet services, catering to different types of data transmission and communication needs:

1. HTTP (HyperText Transfer Protocol)
   • Purpose: Used for transferring web pages and web content.
   • Functionality:
     • Client-Server Model: HTTP operates on a client-server model where the client (usually a web browser) sends a request to the server for a specific resource, and the server responds with the requested resource (e.g., an HTML page, image, or other file).
     • Stateless Protocol: Each request from a client to server is independent; the server does not retain any session information between requests.
     • Methods: Common methods include GET (retrieve data), POST (submit data to be processed), PUT (upload data), and DELETE (remove data).
   • Usage: Browsing websites, downloading web content, and API communications over the web.
2. SMTP (Simple Mail Transfer Protocol)
   • Purpose: Used for sending and relaying email messages.
   • Functionality:
     • Client-Server Communication: An email client sends an email to an SMTP server, which then relays the message to the recipient's email server.
     • Message Transmission: SMTP handles the process of transferring the email message from the sender's mail server to the recipient's mail server.
     • Relaying: Supports relaying messages across multiple servers to reach the final destination.
     • Ports: Typically uses port 25 for communication, with port 587 used for secure transmission.
   • Usage: Sending emails from email clients (like Outlook or Gmail) and relaying emails between mail servers.
3. FTP (File Transfer Protocol)
   • Purpose: Used for transferring files between computers on a network.
   • Functionality:
     • Client-Server Model: FTP operates on a client-server model where an FTP client connects to an FTP server to upload or download files.
     • Control and Data Connections: Establishes a control connection (for commands) and a separate data connection (for transferring files).
     • Authentication: Often requires a username and password for access, though anonymous FTP is also possible.
     • Modes: Can operate in active or passive mode to handle firewall and network address translation (NAT) issues.
   • Usage: Uploading and downloading files to/from websites, transferring large files, and managing files on remote servers.

Each of these protocols is essential for different aspects of internet communication, contributing to the overall functionality and usability of the web.

A web search engine is a software system that is designed to search for information on the World Wide Web. The search results are generally presented in a line of results often referred to as search engine results pages (SERPs). The information may be a mix of web pages, images, and various files. Some search engines also mine data available in databases or open directories. Search engines maintain real-time information by running an algorithm on a web crawler.
Around 2000, Google's search engine rose to prominence and the company achieved better results for many searches with an innovation called PageRank. The name of the paper proposed was called, "Anatomy of a Search Engine written by Sergey Brin and Larry Page."

• Yahoo: By 2000, Yahoo! was providing search services based on Inktomi's search engine. Yahoo! acquired Inktomi in 2002 followed by Overture in 2003. Yahoo! switched to Google's search engine until 2004. In 2004, Yahoo launched its own search engine based on the combined technologies of its acquisitions.

Microsoft first launched MSN Search in the fall of 1998 using search results from Inktomi. In early 1999 the site began to display listings from Looksmart, blended with results from Inktomi. For a short time in 1999, MSN Search used results from AltaVista. In 2004, Microsoft began a transition to its own search technology, powered by its own web crawler (called msnbot).
Microsoft's rebranded search engine, Bing, was launched on June 1, 2009. On July 29, 2009, (Yahoo! and Microsoft) finalized a deal in which Yahoo! Search would be powered by Microsoft Bing technology. In the next lesson, you will learn about the purpose of HTTP and how to deal with common site problems that are HTTP related.