Chapter 8: Web Server Hardware and Software

1. Chapter 8:Web Server Hardware and Software

2. 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 Edition

3. 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 Edition

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 Electronic Commerce, Seventh Annual Edition

5. 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 Electronic Commerce, Seventh Annual Edition

6. Electronic Commerce, Seventh Annual Edition

7. Static Content • Static HTML Web pages – Static information • File Extension: .html or htm Electronic Commerce, Seventh Annual Edition

8. 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 Electronic Commerce, Seventh Annual Edition

9. Electronic Commerce, Seventh Annual Edition

10. Electronic Commerce, Seventh Annual Edition

11. 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 Edition

12. 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 Edition

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

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

15. Spam – Unsolicited E-Mail Electronic Commerce, Seventh Annual Edition

16. Spam by the Numbers (2006) Source: http://spam-filter-review.toptenreviews.com/spam-statistics.html

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

18. Some Filtering Strategies 1. Black List spam filter --Checks incoming messages against a known bad e-mail address list. 2. White List spam filter --Checks incoming messages against a known good e-mail 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 Edition

19. 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 Edition

20. 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) Electronic Commerce, Seventh Annual Edition

21. Server Log File Electronic Commerce, Seventh Annual Edition

22. 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 Edition

23. 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 Edition

24. 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 Edition

25. 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 Edition

26. 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 Electronic Commerce, Seventh Annual Edition

27. Electronic Commerce, Seventh Annual Edition

28. Electronic Commerce, Seventh Annual Edition