Web Server

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Web Server

• A software program or server computer equipped to
  offer World Wide Web access.
• Web servers allow you to serve content over the
  Internet using the Hyper Text
  Markup Language (HTML).
• The Web server accepts requests from browsers
  like Netscape and Internet Explorer and then
  returns the appropriate HTML documents.

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Web Server

• A web server is a computer with special software
  to host web pages and web applications.
• A computer that provides Web services and pages
  to intranet and Internet users.
• A web server serves web pages to clients across
  the Internet or an Intranet. The web server hosts
  the pages, scripts, programs, and multimedia
  files and serves them using HTTP, a protocol
  designed to send files to web browsers and other
  protocols.

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Web Server Cont...

• A number of server-side technologies can be used
  to increase the power of the server beyond its
  ability to deliver standard HTML pages
• These include CGI scripts, server-side includes,
  SSL security, and Active Server Pages(ASPs)

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How Web servers Work - Overview
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How Web servers Work - Overview Cont...

• Perhaps the most important expansion on this was
  the concept of dynamic content (i.e., Web pages
  created in response to a user's input, whether
  directly or indirectly).
• The oldest and most used standard for doing this
  is Common Gateway Interface (CGI)
• It basically defines how a Web server should run
  programs locally and transmit their output
  through the Web server to the user's Web browser
  that is requesting the dynamic content.

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How Web servers Work - Overview Cont...
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Web Server and Browser Interaction

• A Web Browser acts as an interface between the
  user and the Web server
• The browser carries out the following on behalf
  of the user
• Contacts a web server
• Sends a request for information
• Receives the information and
• Displays it on the user's computer

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How Does a Web Server Accept Connections?

• Accept network connections from browsers
• Retrieve content from disk
• Run local CGI programs
• Transmit data back to clients
• Be as fast as possible
• Support multi-threading and multi-processing

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How Do You Organize Web Servers for Performance?

• Dynamic content typically relies on heavy
  database usage or processing of
  other program code, which takes up many
  server-side resources.
• Web site that has grown popular beyond its
  immediate means of serving content and
  ways to spread this load out

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Load Balancing

• DNS balancing (round-robin type)
• Hardware load balancing
• Software load balancing
• Reverse proxying
• Content spreading across hosts
• Content spreading across outsourced providers

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Load Balancing Cont...
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How Does Web Server Security Work?

• Security of the data stream itself so that it may
  not be viewed or modified by a malicious third
  party
• Security of the content itself -- the
  authentication and authorization of people to
  view and change that content

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Personal Web Server

• Microsoft's Personal Web Server (PWS) is a
  scaled-down version of the commercial Information
  Internet Server (IIS) included with the Server
  edition of Microsoft Windows NT.
• Designed for Windows 95/98/ME and Windows NT
  Workstation users.
• PWS is a great entry-level Web server that makes
  it easy to publish personal home pages, serve
  small Web sites, and share documents via a local
  intranet.
• PWS is one of the best servers available for
  helping to get you up and running quickly.

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Personal Web Server Cont

• Wizards are included to guide you through the
  process of setting up home pages and sharing
  files, and the PWS administrator reduces the
  complexity of actually running the Web server
  itself.
• One of the best uses for PWS is as a platform for
  testing out Web sites on your Windows 95/Windows
  NT Workstation computers before hosting them on
  the Internet
• This allows you to check the validity of links,
  scripts, and applications as well as to ensure
  that the overall organization of the site is
  functioning correctly

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Personal Web Server Cont

• The server does include support for Active Server
  Pages (ASP), script debugging
• PWS presents the ability to develop
  transactional Web applications using the
  Microsoft Transaction Server
• No UNIX version, Lacks some of the more advanced
  features included with IIS, Only runs on Windows
  95/98/ME Windows NT Workstation, Slower than IIS

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H/W Requirements

• For Intel-based Windows95/98/ME, Windows NT 4.0
  Workstations
• Intel 486 33 MHz minimum /Pentium 133 MHz
  recommended
• 16 MB RAM minimum / 32 MB RAM recommended
• 40 MB of free HDD Space for installation

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Personal Web Server Installation

• Down load PWS from the site http//www.microsoft.c
  om/msdownload/ntoptionpack/askwiz.asp
• Run setup program and follow the instructions

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Apache Web Server

• Apache remains the king of Web servers despite
  intense efforts by Microsoft and Netscape to gain
  dominance in the market
• Its cross-platform support, protocol support
  (HTTP/1.1), modularity (API), security, logging,
  and overall performance and robustness
• Apache runs on Windows (95/98/NT), OS/2,
  and all the major variants of Unix