I continue to see questions and confusion about the configuration of Internet Information Services (IIS). I hope to clear up some of the confusion by the time you have finished reading this post.
IIS 6 uses a file known as MetaBase.xml located in C:\WINDOWS\system32\inetsrv. As the extension indicates, it is an XML file. Inside of this file is the configuration information for the IIS server as well as the configuration for all the web sites, application pools, and ftp sites. Since this is an XML file, you can make changes to it directly. Here is more information on editing the IIS 6 metabase.
The release of IIS 7 (and subsequent versions such as IIS 7.5 and IIS 8) brought on a new model for the configuration database. Many of the server configuration settings including web sites, application pools, and ftp sites are set up in ApplicationHost.config located in C:\Windows\System32\inetsrv\config. This was a major step forward for IIS, though, as not all settings are kept in the ApplicationHost.config. Some changes are stored in various web.config files allowing developers to define settings such as default pages in their site web.config file that take effect when the file is uploaded to the server. You can also edit the IIS 7 configuration files directly.
Any time you are editing files directly I recommend that you make a backup first. That way if you mess up and edit something inadvertently, you can easily restore the original file.
Rick is a Senior Support Lead at OrcsWeb, a hosted server company providing managed hosting solutions.