The Internet Information Server


IIS is divided up into a number of parts based on the operating system onto which it is being installed, ie. Windows NT Server, Windows NT Workstation and Windows 95/98. The first page is set as default.asp. IIS is the program whci sits on your server machine and responds to the client machine request.

IIS consists of a number of subsections. The diagram below shows the interaction between IIS, the web server and client machines making request on that server.

The default web site of PWS or IIS using an address like http://localhost/ when the browser is running on the same machine as PWS or IIS. One can also use the IP-Address as in http://IP-Address .... Note that one or more IP-Adresses (Internet Protocol) are assigned to each web site and the IPAddresses must also be assigned to the network adapter of the computer hosting the web sites.

Access ASP pages by firstly, installing and setting up PWS or IIS correctly and secondly, as http://localhost[/Virtual Directory]/<filename>.asp. ASP does not require a database engine as a back-end. ASP can most simply create dynamic web pages based on what is available.

This is a simple ASP Example Script.

Different versions of IIS (applicaable to different operating systems) offer different options on IIS.

Adding IPAddresses to Windows NT

Multiple IP Addresses can be added ot a web site in two ways.

To add IP Addresses to a machine with Windows NT machine.

To create a web site check the help files in IIS. Generally the following steps should be followed.

The next steps to consider are the enabling of ISAPI (Internet Server Application Programming Interface) and CGI (Common Gateway Interface) applications.

CGI (Common Gateway Interface)

CGI support is built into most web servers. However, both ASP (Active Server Pages) and JSP (Java Server Pages) should now be a better method of adding dynamic content to a web site. Most CGI applications are written in Perl (Practical Extraction and report Language). Perl is generally used with parsing of email forms. CGI applications are also written in C. CGI allows full manipulation of the operating sustem. The problem with CGI is that for each client requesting a CGI web page a new process has to be created. This takes high server resources and CPU processing time. This problem is exacerbated when multiple clients request a CGI web page.

ISAPI (Internet Server Application Programming Interface)

ISAPI does not spawn a new process for every request as CGI does since ISAPI are implemented in DLL's (dynamic link libraries). DLL's are loaded into the process space of the server which gives faster execution time. ISAPI allows two different application types.

IDC (Internet Database Connector)

IDC allows database access without using CGI or ISAPI DLL extensions. IDC requires two files. The first to contain the query file with SQL statements and the second, a template file, containing commands which convert the query results into an HTML page. IDC allows allow database inserting and updating. Note that IDC allows database access only.

ASP (Active Server Pages)

The object of ASP combines the best of previous technologies.

ASP is an environment which allows server side scripting. This means that high-load processes with large files (high download times) are executed on the server. This minimises network traffic. Network traffic is the biggest bottle-neck in terms of speed of internet access. In the past HTML pages were restricted by being static. With the advent of ASP and JSP web pages can now be interactive. An interactive web page is not static in that its content can change or be changed depending on circumstances. Also with the addition of MTS (Microsoft Transaction Server) ASP is now capable of working in a transacted environment.

Additional technologies for IIS include packages such as Cold Fusion (Allaire) and Visual Basic Web Applications. There are many others.