Chapter 8: Web Server Hardware and Software

Electronic Commerce, Seventh Annual Edition2 Web Server Basics The main job of a Web server computer is to respond to requests from Web client computers Three main elements of a Web server: –Hardware –Operating system software –Web server software

Electronic Commerce, Seventh Annual Edition3 Server Connection WWW requests from the Client computer Browser are detected and handled on port 80 of the server. FTP requests on port 21 of the Server. Mail on port 25 Telnet on port 23

Electronic Commerce, Seventh Annual Edition4 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

Electronic Commerce, Seventh Annual Edition5 Types of Web Sites (continued) Transaction-enabled sites –E-Commerce enabled sites (database, shopping cart, payment processing capability). –Examples: Web Catalog (e-store), Transaction Fee Model, Subscription Model, Auction Sites Content sites –Deliver content such as news, histories, summaries, and other digital information. –Examples: CNN.Com, IBM.com, Portals

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7 Static Content Static HTML Web pages – Static information File Extension:.html or htm

Electronic Commerce, Seventh Annual Edition8 Dynamic Content Dynamic content (DHTML) is nonstatic information constructed on a “Dynamic Webpage” in response to a Web client’s request. (Server-side Scripting) Programs that create dynamic content use these File Extensions:.asp – (Microsoft) - Active Server Pages.jsp – (Sun Microsystems) - Java Server Pages.php – (Apache Open Source) - Hypertext Preprocessor.cfm – (Macromedia) - ColdFusion

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Electronic Commerce, Seventh Annual Edition11 Web Server Operating System Operating system tasks include running programs and allocating computer resources. Unix Windows Open-source software –Developed by a community of programmers who make it available for download at no cost (Example- Linux)

Electronic Commerce, Seventh Annual Edition12 Web Server Software The most popular Web Server programs are: –Apache HTTP Server (Open Source) (JSP, PHP, CFM) –Microsoft (Internet Information Server (IIS) or Microsoft Server 2008) (ASP,.Net) –Sun Java System Web Server (JSWS) (JSP)

Electronic Commerce, Seventh Annual Edition13 Application Servers –Database Server – Manages Product Catalog, Customer database, etc.). –Mail Server – Manages Internet –Proxy Server – Controls access to main computer –Ad Server – Maintains database of banner ads –List Server – Creates and manages special lists.

Electronic Commerce, Seventh Annual Edition14 Spam – Phishing - Virus Spam – Any Unsolicited . Phishing – Amateur & Professional hackers attempting to obtain Personal Information or access to Content. Virus – Malicious Content

Electronic Commerce, Seventh Annual Edition15 Spam – Unsolicited

Spam by the Numbers (2006) Source:

Electronic Commerce, Seventh Annual Edition17 Dealing With the Spam Problem Industry – Can reduce the likelihood that a spammer can automatically generate addresses User – Can control exposure of an address User – Can use multiple addresses User/Server – Can employ content filtering software

Electronic Commerce, Seventh Annual Edition18 Some Filtering Strategies 1. Black List spam filter --Checks incoming messages against a known bad address list. 2. White List spam filter --Checks incoming messages against a known good address list. 3. Challenge-Response technique --Forces a reply to all incoming messages not on a white list. 4. Advanced Content Analysis --Utilizes contextual filtering

Electronic Commerce, Seventh Annual Edition19 Server Firewalls Network Layer Firewall - Filter network traffic based on many packet attributes like IP Address, Domain name and destination port. Application Layer Firewall- inspect all packets for improper application content. Proxy Server – Can serve as a firewall by blocking unwanted content.

Electronic Commerce, Seventh Annual Edition20 Server Data Analysis Software Web Server Log File can capture: –IP Address of Visitor –Type of Request & Pages Viewed or Files Downloaded –Date and time of each activity (timestamp) –Status Code (successful, “404” error etc.) –Type of browser viewed on –Referrer URL (not always available)

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Electronic Commerce, Seventh Annual Edition22 Web Server Hardware Terms 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

Electronic Commerce, Seventh Annual Edition23 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

Electronic Commerce, Seventh Annual Edition24 Factors that can Influence Web Server Performance There is always going to be a limit to the number of pages that a server can serve in a given time frame. Volume - Amount of Web Traffic (Hits) Duty Cycle - No. of CPU-Intensive Operations Capacity - Bandwidth Available

Electronic Commerce, Seventh Annual Edition25 More Web Server Hardware Terms 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

Electronic Commerce, Seventh Annual Edition26 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

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