1. The Web and E-mail Chapter 7

2. 7 Chapter 7: The Web and E-mail2 Chapter Contents  Section A: Web Technology  Section B: Search Engines  Section C: E-commerce  Section D: E-mail  Section E: Web and E-mail Security

3. 7 SECTION A Chapter 7: The Web and E-mail3 Web Technology  Web Basics  HTML  HTTP  Web Browsers  Cookies  Web Page Authoring  HTML Scripts

4. 7 Chapter 7: The Web and E-mail4 Web Basics  The Web is an interlinked collection of document, image, video, and sound files  A Web site contains a collection of related information  Podcasts  RSS vs. Atom  Videocasting

5. 7 Chapter 7: The Web and E-mail5 Web Basics Web page  A Web page is the product or output of one or more Web-based files displayed in a format similar to a page in a book Web browserclient software  A Web browser is client software that displays Web page elements and handles links between pages URL  Every Web page has a unique address called a URL

6. 7 Chapter 7: The Web and E-mail6 HTML  Set of specifications for creating documents that a browser can display as a Web page  Markup language  HTML tags  XHTML – Extensible HTML  DHTML – Dynamic HTML  Ajax – Asynchronous JavaScript and XML

7. 7 Chapter 7: The Web and E-mail7 HTML UTA ExampleExample

8. 7 Chapter 7: The Web and E-mail8 HTTP HTTP messages flow between a browser and a Web server.

9. 7 Chapter 7: The Web and E-mail9 Web Browsers  Help you access Web pages  Upgrade to new browser versions as they become available  Popular browsers: –Internet Explorer –Mozilla Firefox –Apple Safari –Netscape Navigator –Opera

10. 7 Chapter 7: The Web and E-mail10 Web Browsers  Helper applications extend browser’s ability to work with file formats –A plug-in is a type of helper application –A player is any helper application or plug-in that helps a browser display a particular file format

11. 7 Chapter 7: The Web and E-mail11 Cookies  Small chunk of data generated by a Web server and stored on computer’s hard disk –Fix problems caused by HTTP’s stateless protocol –Relatively safe  Your computer does not have to accept cookies

12. 7 Chapter 7: The Web and E-mail12 Web Page Authoring  Text editor  HTML conversion tool  Online Web authoring tools  Web authoring software –Microsoft FrontPage –Adobe Dreamweaver

13. 7 Chapter 7: The Web and E-mail13 HTML Scripts  HTML scripts can perform complicated tasks and respond to user actions –HTML forms –Server-side script –Client-side script –Java applet –ActiveX control  Digital Certificate

14. 7 SECTION B Chapter 7: The Web and E-mail14 Search Engines  Search Engine Basics  Formulating Searches  Citing Web-based Source Material

15. 7 Chapter 7: The Web and E-mail15 Search Engine Basics  A Web search engine is a program designed to help people locate information on the Web by formulating simple keyword queries

16. 7 Chapter 7: The Web and E-mail16 Search Engine Basics Web crawler  A Web crawler is a computer program that is automated to methodically visit Web sites indexer  A search engine indexer is software that culls keywords from a Web page and stores them in a database query processor  A search engine’s query processor looks for your search terms in search engine’s indexed database and returns list of relevant Web sites  Link popularity is measured by quantity and quality of links from one Web page to others meta keyword  A meta keyword is entered into a header section of a Web page when it is created and is supposed to describe the page contents –Keyword stuffing

17. 7 Chapter 7: The Web and E-mail17 Formulating Searches  Most search engines work with keyword queries in which you enter one or more words, called search terms

18. 7 Chapter 7: The Web and E-mail18 Formulating Searches  A Boolean operator is a word or symbol that describes a relationship between keywords, helping you create a more focused query

19. 7 Chapter 7: The Web and E-mail19 Citing Web-Based Source To copy a passage of text from a Web page, highlight the text, click the Edit menu, then select Copy. Next, switch to your own document and use the Paste option.

20. 7 Chapter 7: The Web and E-mail20 Citing Web-Based Source

21. 7 SECTION C Chapter 7: The Web and E-mail21 E-commerce  E-commerce Basics  Online Shopping  Online Auctions  Online Payment

22. 7 Chapter 7: The Web and E-mail22 E-commerce Basics  Business transactions  Business transactions conducted electronically over a computer network –B2C (business-to-consumer) –C2C (consumer-to-consumer) –B2B (business-to-business) –B2G (business-to-government)

23. 7 Chapter 7: The Web and E-mail23 E-commerce Basics  Enhances traditional business models  Styles of online advertisements –Banner ad –Hover ad –Pop-up ad Click-through rate  Ad-blocking software prevents ads from appearing on screens

24. 7 Chapter 7: The Web and E-mail24 Online Shopping Transactions In a typical shopping session, you connect to storefront an online storefront and use navigation controls to browse through the catalog merchant’s catalog. As you browse, you can drop items into your electronic shopping cart electronic shopping cart. At the checkout counter, you enter the information pay necessary to pay for the items you selected.

25. 7 Chapter 7: The Web and E-mail25 Online Shopping

26. 7 Chapter 7: The Web and E-mail26 Shopping Carts

27. 7 Chapter 7: The Web and E-mail27 Online Auctions  An online auction is the electronic equivalent to good old-fashioned yard sales, rummage sales, and auctions  You can expect to bid on new, used, closeout, overstock, or refurbished items at an online auction  Computer software takes the place of an auctioneer

28. 7 Chapter 7: The Web and E-mail28 Online Payment  The most popular ways to make online payments include submitting your credit card number directly to a merchant and using a third-party payment service such as PayPal credit card numbers hijacked and used inappropriately  Online shoppers are justifiably worried that personal information and credit card numbers supplied in the course of an e-commerce transaction might be hijacked and used inappropriately

29. 7 Chapter 7: The Web and E-mail29 Online Payment  A secure connection encrypts the data transmitted between your computer and a Web site SSL (Secure Sockets Layer) S-HTTP (secure HTTP)

30. 7 Chapter 7: The Web and E-mail30 Online Payment  Person-to-person payments are an alternative to credit cards –The payment service is the only entity that sees your credit card number –Service is in its infancy  An electronic wallet is software that stores billing and shipping information

31. 7 Chapter 7: The Web and E-mail31 Online Payment An electronic wallet can transfer your billing and shipping information to a participating site’s e-commerce Web server when you check out.

32. 7 SECTION D Chapter 7: The Web and E-mail32 Web Technology (bonus)  The Internet Protocol Stack  Application Ports

33. 7 Chapter 7: The Web and E-mail33 Internet Protocol Stack standard  Nodes attached to the Internet implement a standard set of capabilities to allow communications between dissimilar systems across dissimilar communications links layeredmodularity ease of implementation  The standard protocol “stack” is implemented in a layered design to support modularity and ease of implementation in many different environments.

34. 7 Chapter 7: The Web and E-mail34 Internet Protocol Stack system software program  Think of each layer as a different system software program that runs on your computer. upper layers like applications  The upper layers allow like applications to communicate lower layers like devices  The lower layers allow like devices to communicate application transport network link physical APPLICATION CATEGORY DEPENDENT OPERATING SYSTEM CONTROLLED NETWORKE HARDWARE DEPENDENT HTTP, etc. TCP or UDP IP Ethernet UTP, fiber, etc.

35. 7 Chapter 7: The Web and E-mail35 Internet Protocol Stack application transport network link physical application transport network link physical Your Client Application Target Server Application Your Messages packets The Internet Web browser, email client, etc. Web server, email server, etc.

36. 7 Chapter 7: The Web and E-mail36 Internet Ports transport network link physical physical  The means by which a single physical node differentiates multiple requests, like email, web, file transfer, etc. transport  The transport layer passes requests to specific “ports” into the application layer 80 25 21 File Transfer Application Email Application Web Server Application

37. 7 SECTION D Chapter 7: The Web and E-mail37 E-mail  E-mail Overview  Netiquette  E-mail Technology

38. 7 Chapter 7: The Web and E-mail38 E-Mail Overview  Any person with an e-mail account can send and receive e-mail messages

39. 7 Chapter 7: The Web and E-mail39 E-Mail Overview  Basic e-mail activities –Writing –Reading –Replying –Forwarding

40. 7 Chapter 7: The Web and E-mail40 E-Mail Overview  E-mail attachments are files that travel with an e-mail message –E-mail software converts e-mail attachments to MIME  HTML-compliant e-mail software  Additional e-mail features

41. 7 Chapter 7: The Web and E-mail41 E-Mail Overview

42. 7 Chapter 7: The Web and E-mail42 Netiquette  Internet etiquette –Meaningful subject –Use uppercase and lowercase letters –Check spelling –Be careful what you send –Be polite –Be cautious with sarcasm and humor

43. 7 Chapter 7: The Web and E-mail43 Netiquette –Use smileys and text messaging shorthand cautiously –Use the Bcc function for group mailings –Don’t send replies to all recipients –Don’t send huge attachments –Explain attachments –Stay alert for viruses –Notify recipients of viruses

44. 7 Chapter 7: The Web and E-mail44 E-mail Technology  E-mail systems carry and manipulate e-mail messages –E-mail servers store-and-forward –Based on store-and-forward technology (SMTP)  Three types of e-mail client systems widely used today: –POP –IMAP –Web-based e-mail

45. 7 Chapter 7: The Web and E-mail45 E-mail Technology POP server  A POP server is a computer that stores your incoming messages until they can be transferred to your hard disk –E-mail client software SMTP server  An SMTP server is a server that forwards emails that you send

46. 7 Chapter 7: The Web and E-mail46 1) Alice uses an email client program to compose a message and “to” bob@someschool.edu 2) Alice’s mail client sends the message to her mail server where it is placed in a message queue (SMTP) 3) Client side of opens a “connection” with Bob’s mail server 4) The client-side mail server sends Alice’s message over the connection (SMTP) 5) Bob’s mail server places the message in Bob’s mailbox on the server 6) Bob opens his email client program to download and read Alice’s message (POP3) user agent mail server mail server user agent 1 2 3 4 5 6 E-mail Technology: SMTP mail Slide from Computer Networks: A Tops-Down Approach, Kurose and Ross

47. 7 Chapter 7: The Web and E-mail47 E-mail Technology: Web mail  Web-based e-mail accounts allow you to use a browser to access your e-mail messages  Messages are sent as form data between the client and the server using HTTP (not SMTP/POP).  Your Web server re-formats and then forwards your email using SMTP. Web Client Mail SMTP mail server user agent 1 2 5 6 7 Web HTTP 4 3 SMTP

48. 7 SECTION E Chapter 7: The Web and E-mail48 Web and E-mail Security  Cookie Exploits  Fake Sites  Spam  Phishing

49. 7 Chapter 7: The Web and E-mail49 Cookie Exploits ad-serving cookie  An ad-serving cookie can track your activities at any site containing banner ads from a third party

50. 7 Chapter 7: The Web and E-mail50 Cookie Exploits  A Flash cookie, also called a local shared object, is the Flash equivalent of a conventional Web cookie  A Web bug or clear GIF is typically a 1x1 pixel graphic embedded in a Web page or e-mail message. It is almost invisible due to its size, and is designed to track who’s reading the Web page or e-mail message  Antispyware is a type of security software designed to identify and neutralize Web bugs, ad-serving cookies, and other spyware

51. 7 Chapter 7: The Web and E-mail51 Cookie Exploits  Individuals who prefer not to leave a trail of their Internet activities surf through an anonymous proxy service, which uses an intermediary, or proxy, server to relay Web page requests after masking the originating IP address

52. 7 Chapter 7: The Web and E-mail52 Fake Sites fake Web site  A fake Web site looks legitimate, but has been created by a third party to be a very clever replica of a legitimate Web site  Pharming  Pharming is an exploit that redirects users to fake sites by “poisoning” a domain name server with a false IP address

53. 7 Chapter 7: The Web and E-mail53 Spam unwanted electronic junk mail  Spam is unwanted electronic junk mail about medical products, low-cost loans, and fake software upgrades that arrives in your online mailbox spam filter  A spam filter is a type of utility software that captures unsolicited e-mail messages before they reach your inbox –Local filtering –ISP filtering

54. 7 Chapter 7: The Web and E-mail54 Spam

55. 7 Chapter 7: The Web and E-mail55 Phishing e-mail based scam  Phishing is an e-mail based scam designed to persuade you to reveal confidential information, such as your bank account number or Social Security number  If you don’t want to become a phishing victim, be suspicious of e-mail messages that supposedly come from banks, ISPs, online payment services, operating system publishers, and online merchants

56. 7 Chapter 7: The Web and E-mail56 Phishing

57. Chapter 7 Complete The Web and E-mail