ASP.NET is configured with XML files. The base server-wide configuration file is called machine.config, described in the next section. This is supplemented by an optional server-wide web.config file located in the same directory as machine.config, and a number of application-specific configuration files, all called web.config, located in the application root directory and subdirectories.
VS2008 goes one step further, offering a different default web.config for ASP.NET 2.0 and ASP.NET 3.5 websites. The main differences between them are the inclusion of Language Integrated Query (LINQ) and AJAX in the 3.5 variant along with the assumption that the site will use the new IIS 7.0 integrated security pipeline. The 2.0 variant is the same as that generated by VS2005.
You can edit the XML files that control the configuration with any standard text editor. It is not necessary to use the IIS control panel, as was the case with classic ASP. Although you can edit the configuration files in any text editor, VS2008 and IIS provide UIs for editing the most common configurations.
Because the configuration is accomplished with XML files and because files are text, it is easy to administer your configuration remotely. Anyone with suitable security clearance can create or edit files from a development machine and then copy them into place via FTP or remote network access. There is no need for the developer to be physically present at the server machine hosting the application ...