Chapter Five

1
ChapterFive

• Web Servers

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Chapter Objectives

• Learn about the Microsoft Personal Web Server
  Software
• Learn how to improve Web site performance
• Learn about absolute and relative URL addresses
• Compare Personal Web Server to other Web servers

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Web Servers

• Web servers are computers connected to the
  Internet and run special Web server software
• Software includes a component called a listener,
  which monitors for Web page requests that are
  sent to the Web server from client browsers

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Web Servers

• When a browser requests a particular Web page
  from a Web server, the Web server sends the HTML
  file for the Web page to the client browser
• The Web server also processes server-side
  programs that create dynamic Web pages

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Personal Web Server

• Personal Web Server (PWS) is software
• Designed to create and manage a Web server, also
  called a Web site, on a desktop computer
• Used to learn how to set up and administer a Web
  site
• Used as a site for testing dynamic Web pages

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Personal Web Server

• A visitor is a user who uses browsers to make
  connections and request Web pages
• PWS can support only 10 Web server connections at
  one time
• A Web server connection corresponds to a socket
  on the Web server
• A socket is an endpoint of a communications
  connection

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Personal Web Server

• Each connection between a client and server
  creates a socket on both the server and client
• Each socket has a corresponding memory location
  that specifies information about the connection
• Each Web server socket also has another
  corresponding memory location that stores
  incoming data requests from the users Web browser

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Personal Web Server

• To make Web pages appear faster, many Web
  browsers can create up to four simultaneous
  connections to a Web site
• PWS Web sites cannot service requests from more
  than two or three simultaneous visitors in a
  timely manner

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Personal Web Server

• Production Web server
• A Web server that can be accessed by anyone
  connected to the Internet
• Personal Web Manager
• A PWS utility
• Allows you to modify the configuration of PWS

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Personal Web Server
Figure 5-1 Personal Web Manager Main page
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Personal Web Server

• Main page
• Shows the URL for your PWS, and drive letter and
  folder path to PWSs root document folder
• Publish page and Web Site pages
• Have wizards that automate the process of
  creating and editing HTML documents and creating
  links to documents

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Personal Web Server

• Tour page
• Provides a basic overview of PWS
• Advanced page
• Allows you to specify the Web servers root
  document directory and default document
  filenames, and to configure other Web server
  properties

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Personal Web Server
Figure 5-2 Advanced Options page
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The Web Server Root Document Directory and
Default Document

• Root document folder
• Central folder containing all Web pages, graphic
  images, programs, and other files available from
  the Web site
• When a visitor specifies in his or her Web
  browser a URL that contains a Web server domain
  name or IP address, but no HTML Web page
  filename, the server returns the HTML document
  that has been specified as the Web server's
  default document

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The Web Server Root Document Directory and
Default Document

• To make Web pages appear faster, most Web
  browsers are configured to cache, or save,
  recently viewed Web pages on the local hard drive
• Every computer that connects to the Internet must
  have a unique IP address

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The Web Server Root Document Directory and
Default Document

• Some computers have static IP address, which are
  IP addresses that
• Never changes and refers only to a specific
  computer
• Are assigned to computers that stay in the same
  physical location or computers that are servers
• Dynamic IP address
• Assigned to a computer from a list of available
  addresses each time the computer is booted and
  its Internet access software is loaded
• Might change each time the computer is booted

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Directory Browsing

• Directory browsing
• Allows Web site visitors to use a folder listing
  to navigate to different files on the Web server
• When enabled, PWS will display a list of all
  files in the root document folder if the default
  document file is not specified or found

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Directory Browsing
Figure 5-4 Listing of PWS root document folder
contents
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The Web Site Activity Log

• Web Site Activity Log
• Maintains a list of the IP addresses of computers
  that connect to your Web site

Figure 5-6 Web Site Activity Log file
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The Web Site Activity Log

• Log file
• Contents can be viewed using any text editor or
  word processor

Figure 5-7 Log file contents
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The Web Site Activity Log

• When using IP addresses in the log file to
  identify who is accessing your Web site
• Visitors with dynamic IP addresses usually cannot
  be identified
• Visitors with static IP addresses and associated
  domain names can sometimes be identified, using a
  utility named Nslookup

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The Web Site Activity Log
Figure 5-8 Using Nslookup to find the identity
of a Web site visitor
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The Web Site Activity Log

• Information about domain names can be located
  using Web-based services that maintain
  information about domain names

Figure 5-9 Information about a Web site
visitors domain name
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Creating Virtual Directories

• Virtual directory
• Folder that does not have to be physically within
  the root document folder, but always appears to
  client browsers as though it is
• Alias
• Name client browsers can use to access that
  directory
• Usually shorter than the folder pathname
• More secure since visitors do not need to know
  the names of folders where your server files are
  located

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Creating Virtual Directories
Figure 5-10 Virtual directory properties
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Creating Virtual Directories
Figure 5-11 Folder listing of a virtual directory
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Creating Virtual Directories
Figure 5-12 Creating a virtual directory
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Managing Virtual Directory Access Privileges

• Read access
• Enables a visitors Web browser to read or
  download files stored in virtual directory
• Execute access
• Enables Web clients to run compiled (executable)
  Web applications as well as server-side scripts
  stored in a virtual directory

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Managing Virtual Directory Access Privileges

• Scripts access
• Enables a visitors browser to run only scripts
  that are stored in the virtual directory, not
  executable programs

Table 5-1 Virtual directory privilege types and
associated file types
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Managing Virtual Directory Access Privileges
Figure 5-13 Creating the cgi-bin virtual
directory
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Monitoring Web Site Performance

• Monitoring section of Personal Web Manager Main
  page allows you to monitor statistics about
  visits to your Web site
• Data are collected about the following items
• Active connections, Started at, Visitors,
  Requests, Bytes served, and Most concurrent
  connections

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Monitoring Web Site Performance

• Active connections
• Represents number of active server connections
  currently being used to transfer data to visitor
  browsers
• Started at
• Shows when the server was last started
• Visitors
• Shows number of unique IP addresses connected to
  the server since the workstation was last started

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Monitoring Web Site Performance

• Requests
• Shows number of requests received since the
  computer was last restarted
• Bytes served
• Shows total amount of data sent since last
  restart
• Most concurrent connections
• Shows number of connections opened to the server
  simultaneously since the computer was last started

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Monitoring Web Site Performance
Figure 5-14 Viewing the monitoring statistics
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Factors Affecting Web Site Performance

• Factors affecting time it takes a Web site to
  service a visitor request include
• Speed of the Web servers network connection
• Amount of main memory that a Web server has
  allocated to process Web page requests
• Web servers processor speed

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Factors Affecting Web Site Performance

• Factors affecting time it takes a Web site to
  service a visitor request include (cont.)
• Number of other visitors currently requesting Web
  site pages or files
• Size of Web page files and number and size of
  their embedded graphic object files
• Resources needed by Web-based programs and
  scripts in Web pages

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Referencing Files on a Web Server

• When referencing an object on a Web page that is
  stored on a Web server, the referenced object
  must be in same folder as the Web page that is
  currently displayed
• Saving copies of all Web pages and their
  associated graphic objects in multiple folders on
  a Web server is not an effective way to use disk
  space

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Referencing Files on a Web Server

• When you change a Web page HTML file, you might
  not remember to update all the copies of the page
  file if they stored in multiple places
• A better way to manage referenced objects is by
  specifying object locations using absolute or
  relative URL addresses

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Absolute URL Addresses

• Absolute URL address
• Can be used in browsers Address box or in a
  hyperlink tag to specify complete path location
  of a Web page file
• Includes the Web server IP address or domain
  name, the complete folder path or virtual
  directory path to the Web page file, and the name
  of Web page file

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Absolute URL Addresses
Figure 5-15 Absolute URL addresses
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Relative URL Addresses

• Relative URL address
• Specifies the location of a file relative to the
  current working directory

Table 5-2 Relative path addresses
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Comparing PWS to Other Web Servers

• PWS
• Supports the most common server-side programming
  approaches that can be used with production Web
  servers
• Can run CGI programs or scripts and Active Server
  Pages (ASPs)
• IIS
• More sophisticated administrative features

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Comparing PWS to Other Web Servers

• Internet Service Manager (ISM) utility within
  IIS
• Supports directory browsing that can be enabled
  or disabled for specific directories rather than
  for the entire Web site
• Provides Write access for virtual directories
• Allows visitor browsers to upload and download
  files to a Web server

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Comparing PWS to Other Web Servers

• Internet Service Manager (ISM) utility within IIS
  (cont.)
• Allows the Web server administrator to tune the
  Web site for number of expected hits per day
• Provides a higher level of security through NT
  file system permissions

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Summary

• Personal Web Server (PWS) is software designed to
  create and manage a Web server on a desktop
  computer
• Personal Web Manager is a utility used to
  configure and monitor PWS
• Personal Web Manager is used to specify the Web
  site root document directory, and the name of the
  default document
• PWS support directory browsing

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Summary

• A Web browsers current working directory is the
  folder that contains the Web page that is
  currently displayed
• PWS provides an excellent environment for
  learning about Web servers, and for testing Web
  programs and new Web pages