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

HTTP, SMTP, and FTP are foundational protocols that enable specific internet services by defining how data is transmitted and processed across networks. Here's how each contributes: HTTP (Hypertext Transfer Protocol):

HTTP facilitates web browsing by enabling communication between clients (e.g., browsers) and servers. It uses a request-response model where clients send requests (e.g., GET to retrieve a webpage) to servers, which respond with resources like HTML pages, images, or APIs. Operating over TCP/IP, typically on port 80 (or 443 for HTTPS), HTTP is stateless, meaning each request is independent. It supports methods like POST for sending data, making it essential for accessing and interacting with websites and web applications.

SMTP (Simple Mail Transfer Protocol):

SMTP powers email delivery by transferring messages between mail servers and from clients to servers. Operating over TCP, usually on port 25 (or 587 for secure submissions), SMTP defines how email messages are formatted, sent, and relayed. It works with protocols like POP3 or IMAP for email retrieval. SMTP uses a store-and-forward model, ensuring emails reach their destination via intermediate servers, often with extensions like ESMTP for added security (e.g., TLS encryption).

FTP (File Transfer Protocol):

FTP enables file transfers between a client and a server over a network, typically on ports 20 (data) and 21 (control). It supports uploading, downloading, and managing files, using separate channels for commands and data. FTP operates over TCP and supports authentication, though it’s less secure unless paired with encryption (e.g., FTPS or SFTP). It’s widely used for sharing large files or managing server directories, though modern alternatives like cloud storage are gaining traction.

Each protocol is tailored to its service, HTTP for web content, SMTP for email, and FTP for file transfers—forming the backbone of key internet functionalities.

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.