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Book 1

• Chapter 1
• Chapter 2
• Chapter 3
• Chapter 4
• Chapter 5
• Chapter 6
• Chapter 7
• Chapter 8
• Chapter 9
• Chapter 10
• Chapter 11
• Chapter 12
• Chapter 13
• Chapter 14
• Chapter 15
• Chapter 16/17
• Chapter 18/19
• Chapter 20
• Chapter 21
• Chapter 22/23

Book 2

• Chapter 1
• Chapter 2
• Chapter 3
• Chapter 4
• Chapter 5
• Chapter 6
• Chapter 7
• Chapter 9
• Chapter 10

Ch.15 HTTP Servers

A HTTP server is commonly known as a Web server. It serves HTML documents on the Internet, Intranets, Extranets, LANs and WANs. The web server uses software that listens on TCP port 80 for a HTTP request, then responds with a file from a specific directory configured by the server administrator.

Popular web servers include:

• Apache
  A freeware HTTP server that runs on UNIX and Windows NT.
• Netscape Enterprise Server
  Runs on Unix and NT.
• Microsoft Internet Information Server (IIS)
  Runs on NT.

Microsoft's Personal Web Server allows standard PC's running Windows NT/95/98 to function like a web server.

Microsoft's Internet information Server allows standard PC's running Windows NT/2000 to function like a web server.

Ports

A port is a logical connection point. Clients access servers using a consensual specified port, depending on the service. Port numbers range from 0 to 65536. Ports 0 through 1024 are reserved for certain privileged services.

• Port 80 is the default port for HTTP servers.
• Port 443 is used for Secure Sockets layer (SSL).
• Ports are also used for remote web server administration through a browser interface. The port is specified by the Web system administrator.

Server side technologies

Server side technologies allows servers to play a more proactive role in distributing dynamic content. It allows the server to perform functions on the web server based on client input, then return relevant HTML content. These technologies include:

• Common Gateway Interface (CGI)
  Is not a language, but a simple protocol that can be used to communicate between HTML forms and an application. A common use is the Guestbook. Can also be used to extract data from a database or file on the web server. Uses the .cgi or .pl file name extension and are written in Perl, C or shell scripting.
• Server-side Includes (SSI)
  Small snippets of code are inserted into the HTML document, linking to a HTML document or a text document. The requested document is shown as part of the parental HTML document.
• Active Server pages (ASP)/Java Server Pages (JSP)
  Technologies that enable data and applications to be run on the server before information is sent to the client. ASP and JSP code is executed on the server at the time a client requests a page. The server then processes the code and sends the result to the client. In addition, the server removes all the coding instructions it just processed, so that the client browser only receives HTML. Thus the technology is not reliant on browser-type.
  JSP can run on multiple platforms. ASP will only run on IIS or Windows 2000 servers.
• Server-side JavaScript (SSJS)

Chapter 14 Chapter 16/17