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

Web Server Hardware and Software  Discussion Objectives  Web server basics  Software for Web Servers  management and spam control  issues  Internet and Web site utility programs  Web server hardware

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

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

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

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

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

Figure 1

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

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.

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

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

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

Web Client/Server Communication

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

Figure 2

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

Figure 3

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

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

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

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

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)

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

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

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

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

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

Web Server Software (cont.) Finding Web Server Software Information Netcraft Web site:

Electronic Mail.K. Since 1972

Benefits  First Internet Application  Attachment available  used as a receipt of customer orders  Information update about purchases and shipment

Drawback  Time consuming  Computer Virus  Unsolicited commercial s Waste of time and disk space Consuming large amount of Internet capacity Offensive Tremendous growth

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

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

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 address  Technical solutions

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

Server Hardware

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

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

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

Load-balancing systems

Complex load balancing

QUESTIONS?