Every web application inherits the settings from the machine.config file.
You can apply application-specific settings.
The entire content of an ASP.NET configuration file is nested in a root element.
element is used for ASP.NET settings.
Inside the element are separate elements for each aspect of configuration.
ASP.NET uses a multilayered configuration system.
To use this technique, you need to create additional subdirectories inside your virtual directory.
These subdirectories can contain their own web.config files.
ASP.NET uses configuration inheritance so that each subdirectory acquires the settings from the parent directory.
If settings conflict, the settings from a web.config in a nested directory always override the settings inherited from the parent.