Web Server Hardware and Software

1. Web Server Hardware and Software Presented by: Trung NGUYEN Emilie MARTIN

2. Web Server Hardware and Software • Discussion Objectives • Web server basics • Software for Web Servers • E-mail management and spam control • issues • Internet and Web site utility programs • Web server hardware

3. Web Server Basics • Web server computer’s main job: respond to requests from Web client computers • Web server’s main elements: hardware (computers and related components), operating system software, and Web server software

4. Types of Web Sites • Development sites: simple sites used to evaluate different Web designs with little initial investment • Intranets: corporate networks • Extranets: intranets that allow authorized outsiders to access certain parts of the system

5. Types of Web Sites • Transaction-processing sites: electronic commerce sites available 24/7 • Content-delivery sites: deliver news, histories, summaries, and other digital information

6. Web Clients and Web Servers • Web client computer: used by people through their Internet connections to be part of the Web • Web server computer: computer used to process Web client computers’ requests; have more memory and larger, faster disk drives then client computers

7. Web Clients and Web Servers (cont.) • Web browser software (Microsoft Internet Explorer, Netscape Navigator): software that makes computers work as Web client, also called Web client software • Web software: platform neutral, let computers communicate with each other easily and effectively

8. Figure 1

9. Dynamic Content • Dynamic page: a Web page whose content is shaped by a program in response to user requests • Static page: an unchanging page retrieved from disk • Dynamic content: nonstatic information constructed in response to a Web client’s request

10. Two basic approaches to create customized pages • Server-Side Scripting/Technologies : slow, programs create the Web pages before sending them to the requesting Web clients as parts of response messages • Dynamic Page-Generation Technologies: server-side scripts are mixed with HTML-tagged text to create the dynamic Web page.

11. Two basic approaches to create customized pages (cont.) Dynamic Page-Generation Technologies example: • Active Server Pages by Microsoft • JavaServer Pages by Sun Microsystems • Hypertext Preprocessor by open-source Apache Software Foundation

12. Various Meaning of “Server” • “Server”: confusedly used in many different ways • Server: any computer used to make files/programs available to other computers connected to it through a network (a LAN or a WAN) • Server software: software that used by server computer to make files/programs available to other computers

13. Various Meaning of “Server” • Web server: computers contain document made publicly available through Internet connections • Web server software: software used by Web server

14. Web Client/Server Communication

15. Two-Tier Client/Server Architecture • Basic Web client/server model, has only one client and one server • Messages are created and read only by the client and server computers

16. Figure 2

17. Three-Tier and N-Tier Client/Server Architectures • Allow additional processing to occur before the Web server responds to the Web client’s request • Includes databases and related software applications that supply information to the Web server • Can track customer purchases stored in shopping carts, look up sales tax rates, keep track of customer preferences, query inventory databases

18. Figure 3

19. Software for Web Servers Operating systems for Web servers: • Run programs and allocate computer resources such as memory and disk space to programs • Provides input and output services to devices connected to the computer, including keyboard, monitor, and printers

20. Operating systems Microsoft server products: • Windows NT Server, Microsoft Windows 2000 Server or Server 2003 • Believed simpler to learn and use than UNIX-based systems • Have security weaknesses caused by the tight integration between application software and the operating system

21. Operating systems (cont.) UNIX-based Operating System: • Solaris or FreeBSD: • More popular, more secure operating system to run a Web site

22. Operating systems (cont.) Linux: • Open-source operating system that is easy to install, fast, and efficient • Open Source Initiative Web site: www.opensource.org • Commercial Linux distributors: SuSE, Caldera, mandrake, Red Hat

23. Web Server Software Most commonly used Web server programs (conducted by Netcraft (England)): • Apache HTTP Server • Microsoft Internet Infor Server (IIS) • Sun Java System (JSWS) (Sun ONE, iPlanet, Netscape)

24. Web Server Software (cont.) Apache HTTP Server: • Developed by Rob McCool in 1994 • Currently available at no cost as open-source software • Dominated the Web since 1996 • Account for 65-70% of Web server market share

25. Web Server Software (cont.) Microsoft Internet Information Server (IIS) • Used by many corporate intranets • Account for 20-25% of Web server market share, has been decreasing as a victim of several well-publicized security breaches

26. Web Server Software (cont.) Sun Java System Web Server (JSWS): • Often called by Sun ONE, iPlanet Enterprise Server, Netscape Enterprise Server • Not free, but licensing fee is reasonable

27. Web Server Software (cont.) • Market share for Intranet Web servers are quite different than for public Web servers (PC Magazine Survey) • Microsoft IIS and Sun servers account for 75% of installed intranet server programs

28. Web Server Software (cont.) • Large company Web sites and high traffic Web sites prefer Sun servers • Performance of Web servers differ based on workload, operation system, type and size of Web page servers

29. Web Server Software (cont.) Finding Web Server Software Information Netcraft Web site: WWW.netcraft.com

30. Electronic Mail .K. E-mail Since 1972

31. E-mail Benefits • First Internet Application • Attachment available • E-mail used as a receipt of customer orders • Information update about purchases and shipment

32. E-mail Drawback • Time consuming • Computer Virus • Unsolicited commercial e-mails • Waste of time and disk space • Consuming large amount of Internet capacity • Offensive • Tremendous growth

33. Solutions to the Spam Problem • Individual User Anti-Spam • Reduce the likelihood for automatic spam • Control exposure of an e-mail address • Use multiple e-mail addresses • Basic content filtering • Examining e-mail headers: client-level or server-level filtering • Black lists • White lists

34. Solutions to the Spam Problem • Challenge-response content filtering • Advanced Content Filtering • Bayesian revision • POPFile

35. Solutions to the Spam Problem • Legal solutions: CAN-SPAM • Misleading address header information • Deceptive subject headers • Clear & conspicuous notice of message nature • Physical postal address • Mandatory provision of an opt-out mechanism • Effectiveness of opt-out mechanism • Transfer of e-mail address • Technical solutions

36. Web Site and Internet Utility Programs

37. Web Site and Internet Utility Programs • Finger and Ping Utilities • Tracert and other Route-Tracing Programs • Telnet and FTP Utilities • Indexing and Searching Utility Programs • Data Analysis Software • Link-Checking Utilities • Remote Server Administration

38. Server Hardware

39. Web Server Hardware • Server Computers • More memory • Larger and faster hard disk drives • Faster processors • More expensive • Blade servers

40. Web Server Hardware • Web Server Performance Evaluation • Hardware • Operating system software • Server software • Connection speed • User capacity • Type of Web pages being delivered • Speed of connection: T3 is faster than T1 • Throughput • Response time

41. Web Server Hardware • Web Server Architecture • Centralized architecture • Expensive computers • Sensitive to technical problems • Distributed architecture • Cheaper • Less sensitive • Additional cost on hubs and switches

42. Load-balancing systems

43. Complex load balancing

44. QUESTIONS?