Configuring Anonymous FTP Authentication (IIS 6.0)
You can configure your FTP server to allow anonymous access to FTP resources. If you select Anonymous FTP authentication for a resource, all requests for that resource are accepted without prompting the user for a user name or password. This is possible because IIS automatically creates a Windows user account called IUSR_computername, where computername is the name of the server on which IIS is running.
You must be a member of the Administrators group on the local computer to perform the following procedure or procedures. As a security best practice, log on to your computer by using an account that is not in the Administrators group, and then use the runas command to run IIS Manager as an administrator. At a command prompt, type runas /User:Administrative_AccountName "mmc systemroot\system32\inetsrv\iis.msc".
To enable Anonymous FTP authentication
Configuration settings made at the FTP Sites level are inherited by all of the FTP sites on the server. You can override inheritance by configuring the individual site or site element.
If you change the security settings for your Web site or virtual directory, your Web server prompts you for permission to reset the security settings for the child keys of that site or directory. If you choose to accept these settings, the child keys inherit the security settings from the parent site or directory.