It is important to understand the distinction between Web server permissions and NTFS permissions. Unlike NTFS, Web server permissions apply to all users accessing your Web and FTP sites. NTFS permissions apply only to a specific user or group of users with a valid Windows account. NTFS controls access to physical directories on your server, whereas Web and FTP permissions control access to virtual directories on your Web or FTP site. For more information, see Web and FTP Sites.
By default, Web and FTP access permissions use the Windows account IUSR_computername, but Hosting Controller creates an anonymous account upon IIS site creation, with the name of that site. e.g. If you have created site www.mydomain.com, then an anonymous user with the name mydomain.com_web is also created . When users access your site, using anonymous authentication, they use this account. By default, this anonymous user is given NTFS permissions by IIS for the actual folders that comprise the Web or FTP site. You can, however, change these permissions for any folder or file in your site. For example, you can use Web server permissions to control whether users visiting your Web site are allowed to view a particular page, upload information, or run scripts on the site.
Important
If Web permissions and NTFS permissions differ for a directory or file, the more restrictive settings are used.
Your Web server will prompt you for permission to reset the properties of individual directories and files when you attempt to set security properties for your Web site or a virtual directory. If you choose to reset these properties, your previous security settings will be replaced by the new settings.