5 ChapterFive
Web Servers
5 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
5 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
5 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
5 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
5 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
5 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 user’s Web browser
5 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
5 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
5 Personal Web Server
Figure 5-1: Personal Web Manager Main page
5 Personal Web Server
• Main page– Shows the URL for your PWS, and drive letter
and folder path to PWS’s 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
5 Personal Web Server
• Tour page – Provides a basic overview of PWS
• Advanced page – Allows you to specify the Web server’s root
document directory and default document filenames, and to configure other Web server properties
5 Personal Web Server
Figure 5-2: Advanced Options page
5 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
5 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
5 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
5 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
5 Directory Browsing
Figure 5-4: Listing of PWS root document folder contents
5 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
5 The Web Site Activity Log
• Log file– Contents can be viewed using any text editor or
word processor
Figure 5-7: Log file contents
5 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
5 The Web Site Activity Log
Figure 5-8: Using Nslookup to find the identity of a Web site visitor
5 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 visitor’s domain name
5 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
5 Creating Virtual Directories
Figure 5-10: Virtual directory properties
5 Creating Virtual Directories
Figure 5-11: Folder listing of a virtual directory
5 Creating Virtual Directories
Figure 5-12: Creating a virtual directory
5 Managing Virtual Directory Access Privileges
• Read access– Enables a visitor’s 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
5 Managing Virtual Directory Access Privileges
• Scripts access– Enables a visitor’s 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
5 Managing Virtual Directory Access Privileges
Figure 5-13: Creating the cgi-bin virtual directory
5 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
5 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
5 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
5 Monitoring Web Site Performance
Figure 5-14: Viewing the monitoring statistics
5 Factors Affecting Web Site Performance
• Factors affecting time it takes a Web site to service a visitor request include: – Speed of the Web server’s network connection– Amount of main memory that a Web server has
allocated to process Web page requests– Web server’s processor speed
5 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
5 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
5 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
5 Absolute URL Addresses
• Absolute URL address– Can be used in browser’s 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
5 Absolute URL Addresses
Figure 5-15: Absolute URL addresses
5 Relative URL Addresses
• Relative URL address– Specifies the location of a file relative to the
current working directory
Table 5-2: Relative path addresses
5 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
5 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
5 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
5 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
5 Summary
• A Web browser’s 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