1 / 37

Chapter 8: Web Server Hardware and Software

Chapter 8: Web Server Hardware and Software. Objectives. In this chapter, you will learn about: Web server basics Software for Web servers E-mail management and spam control issues Internet and Web site utility programs Web server hardware. Web Server Basics.

lynde
Download Presentation

Chapter 8: Web Server Hardware and Software

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 8:Web Server Hardware and Software

  2. Objectives In this chapter, you will learn about: • 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 • The main job of a Web server is to respond to requests from Web client computers • There are 3 components of a Web server: • Hardware • Operating system software • Web server software

  4. Types of Web Sites • Development sites: Used to evaluate different Web designs • Intranets: Corporate networks that house internal memos, corporate policy handbooks, and a variety of other corporate documents • Extranets: Intranets that allow authorized parties outside the company to access information stored in the system • Transaction-processing sites: Commerce sites that must be available 24 hours a day, seven days a week • Content-delivery sites: Deliver content such as news, histories, summaries, and other digital information

  5. Web Clients and Web Servers • Client/server architectures • Client computers request services • A server processes the clients’ requests • Web software is platform neutral, meaning that it lets different types of servers communicate with a variety of clients

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

  7. Dynamic Content • Server-side scripting (or includes) • Programs running on a Web server create Web pages before sending them back to the requesting Web clients • Dynamic page-generation technologies: Server side scripts are combined with html tags to create dynamic content • Active Server Pages (ASP) • JavaServer Pages (JSP) • PHP: Hypertext Preprocessor (PHP)

  8. Various Meanings of “Server” • Server • Computer used to provide files or make programs available to other computers • Server software: Used by a server to make files and programs available to other computers • Database server: Server on which database management software runs

  9. Two-Tier Client/Server Architecture • Two-tier client/server architecture has one client and one server

  10. Two-Tier Client/Server Architecture • Request message: Message that a Web client sends to request a file or files from a Web server • Typical request message contains: • Request line • Contains a command, the name of the target resource, and the protocol name and version number • Request headers • Can contain information about types of files that the client will accept in response to a request • Entity body • Used to pass bulk information to the server

  11. Three-Tier and N-Tier Client/Server Architectures • Three-tier architecture • Extends two-tier architecture to allow additional processing (e.g., collection of data from a database) before reponses to requests are made • N-tier architectures • Higher-order architectures • Third tier includes software applications that interactively supply and update information to and from the web server

  12. Web Server Software • The most popular Web server programs are: • Apache HTTP Server • Microsoft Internet Information Server (IIS) • Sun Java System Web Server (JSWS) • Netcraft • A networking consulting company in Bath, England • Accumulates popularity rankings

  13. Apache HTTP Server • Apache is the results of an ongoing group software development effort, first developed by Rob McCool at the University of Illinois in 1994 at theNCSA • Apache has dominated the Web since 1996 because it is free (open source) and performs efficiently

  14. Microsoft Internet Information Server • Comes bundled with current versions of Microsoft Windows Server operating systems • Used on many corporate intranets • Supports the use of: • ASP • ActiveX Data Objects • SQL database queries

  15. Electronic Mail (E-Mail) • We all know the benefits of email • Email drawbacks include: • Time spent by business people responding to e-mail • Computer viruses • Programs that attach to other programs • Can cause damage when the host program is activated • Spam

  16. Spam • Spam is unsolicited or commercial e-mail • During one 24-hour period in 2005 researchers estimated that 106 billion spam e-mail messages were sent

  17. Solutions to the Spam Problem • Reduce the likelihood that a spammer can automatically generate e-mail addresses • Control exposure of an e-mail address • Use multiple e-mail addresses • Content filtering strategy • Requires software that identifies content elements that indicate if a message is (or is not) spam

  18. Solutions to the Spam Problem • Content-filtering techniques • Black list spam filter • Looks for known spammer From addresses in incoming messages • White list spam filter • Examines From addresses and compares them to a list of known good sender addresses • Challenge-response technique • Compares all incoming messages to a white list

  19. Web Site and Internet Utility Programs • Finger • Runs on UNIX operating systems • Allows users to obtain information about other network users • Command yields a list of users who are logged on to a network • Ping (Packet Internet Groper) • Tests connectivity between two computers connected to the Internet

  20. Tracert and Other Route-Tracing Programs • Tracert (TRACE RouTe) • Sends data packets to every computer on the path between one computer and another • Clocks packets’ roundtrip times • Calculates and displays the number of hops between computers • Calculates the time it takes to traverse an entire one-way path between machines

  21. Telnet and FTP Utilities • Telnet • Program that allows users to log on to a computer connected to the Internet • Telnet protocol • Set of rules used by Telnet programs • File Transfer Protocol (FTP) • Defines formats used to transfer files between TCP/IP-connected computers

  22. Indexing and Searching Utility Programs • Search engines or search tools • Search either a specific site or the entire Web for requested documents • Indexing program • Can provide full-text indexing that generates an index for all documents stored on a server • Can often index documents stored in many different file formats

  23. Data Analysis Software • Web servers can capture: • Data about who is visiting a Web site • How long the visitor’s Web browser viewed the site • Date and time of each visit • Which pages a visitor viewed • Data captured by Web servers are stored in a log file

  24. Link-Checking Utilities • Link checker examines each Web page and reports on URLs that: • Are broken • Seem broken • Are incorrect in some way • Orphan file • File on a Web site not linked to any page • Dead link • When clicked, it displays an error message rather than a Web page

  25. Remote Server Administration • Web site administrator can control a Web site from any Internet-connected computer • NetMechanic • Offers a variety of link-checking, HTML troubleshooting, site-monitoring, and other programs

  26. Web Server Hardware • Web server computers • More memory, larger hard disk drives, and faster processors than typical PCs • Blade servers • Placing small server computers on a single computer board, then installing boards into a rack-mounted frame • Virtual server (virtual host) • Maintains more than one server on one machine

  27. Web Server Performance Evaluation • Benchmarking • Testing used to compare the performance of hardware and software • Throughput • Number of HTTP requests that a hardware and software combination can process in a unit of time • Response time • Time required by a server to process one request

  28. Web Server Hardware Architectures • Server farms • Large collections of servers • Centralized architecture • Uses a few very large and fast computers • Distributed/decentralized architecture • Uses a large number of less powerful computers • Divides the workload among them

  29. Load-Balancing Systems • Load-balancing switch • Piece of network hardware that monitors the workloads of servers attached to it • Assigns incoming Web traffic to a server that has the most available capacity at that instant in time

  30. Summary • The Web uses a client/server architecture • For simple HTTP requests a two-tier architecture works well • Operating systems commonly used on Web server computers include: • Microsoft server operating systems • UNIX-based operating systems

  31. Summary • Utility programs running on Web server computers include: • Finger, Ping, Tracert, e-mail server software, Telnet, and FTP • Unsolicited commercial e-mail (spam) has grown dramatically in recent years • Content filters are becoming available to deal with the problem

  32. Summary • Web server hardware • Server computer must have enough memory and disk space • Factors that affect Web server performance include: • Operating system • Connection speed • User capacity

More Related