IIS 7.0 was a complete rewrite of the base code from IIS 6.0 and earlier. Available on Windows Vista and Windows Server 2008, IIS 7.0 adapted to several operating systems, including the new Windows Core Edition and the Windows Web Server edition. IIS 7.5, introduced with Windows 7, consisted of IIS 7.0 plus all the inline updates that had been made to IIS 7.0 since its introduction. Users could essentially update IIS 7.0 to the functionality of IIS 7.5 by installing the appropriate updates and modules.
IIS 7.0 was a ground-up rewrite of IIS 6.0, designed as an integrated web application platform. Integration with the ASP.NET framework combined with fully exposed application programming interfaces (APIs) for complete extensibility of the platform and management interfaces made IIS 7.0 a programmer's dream. Security that included delegation of configuration and a complete diagnostic suite with request tracing and advanced logging satisfied several of the administrator's desires.
Although the most substantial change in IIS 7.0 may have been the integration of ASP.NET into the request pipeline, the extensibility of IIS 7.0, configuration delegation and the use of XML configuration files, request tracing and diagnostics, and the new administration tools were all welcome changes from previous versions of IIS.
Unlike previous versions of IIS, the modular design of IIS 7.0 allowed for easy implementation of custom modules and additional functionality. This increased functionality ...