Chapter 8 Key Concepts

Web Server Basics
3 Elements of a Web Server:
-Hardware (computers and related components)
-Operating system software
-Web server software

Types of Web Sites:
-Development sites (simple sites that companies use to evaluate different Web designs)
-Intranets (corporate in-house networks)
-Extranets (Intranets that allow certain authorizes parties outside the organization, such as suppliers or partners, to access certain parts of their information systems)
-Transaction-processing sites (commerce sites, such as B2B and B2C)
-Content-delivery sites (sites that deliver content, such as news and other digital information)

Web Clients and Web Servers
-Web Client: when a person uses their Internet connection to become part of the Web, by requesting services such as database access, information retrieval, etc.
-Web Server: the computers that perform these requests, which often have more memory and larger, faster disk drives.
-Dynamic Content: non-static information constructed in response to a Web Client’s request.
-server-side scripting: programs running on the Web server create the Web pages before sending them back to the requesting Web clients as part of response messages.
-dynamic page generation technologies include JavaServer Pages (JSP) and Active Server Pages (ASP).
-Web browser software: includes Microsoft Internet Explorer or Netscape Navigator.

Various meanings of “Server”
-any computer used to provide or serve files or make programs available to other computers connected through a network such as a LAN or WAN.

Web Client/Server Communication
-is exchanged using HTTP between the Client (making the request) and the Server (fulfilling the request)

Two-Tier Client/Server Architecture
-the basic Web client/server model is a Two-Tier model, because there is only one client and one server.
-the Web client sends a request message, and receives a response message in return.

Three-Tier and N-Tier Client/Server Architectures
-extends two-tier to include more complex processing such as retrieving files from a database to generate a dynamic web page. N-tier architectures have more than three tiers.

Electronic Mail
Benefits
-one of the first Internet Applications
-documents, pictures, movies, worksheets, etc can be sent along with the message as attachments
-simple and fast
Drawbacks
-time spent answering emails
-computer viruses
-Spam (unsolicited commercial email)
-Black-list filtering: blocks addresses that are known spammers
-White-list filtering: allows messages from known contacts

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

Web Server Hardware
Server Computers
Web Server Performance Evaluation
Web Server Architecture