There are two levels of authentication for an IIS server hosted on Windows 2000: Web authentication and New Technology File System (NTFS) permissions.
IIS authentication is set through the Internet Service Manager (ISM), which can be accessed from the server's Administrative Tools menu. Under the Directory Security tab, there are a variety of authentication options that can be checked off. These include options for Basic Authentication, Digest Authentication, as well as Integrated Windows Authentication.
The ISM allows more than one type of authentication to be selected. The pop-up window you describe could be a Basic or Digest authentication window, so make sure these two options are deselected.
The other reason for the authentication window issue could be that the NTFS permissions in the server's root directory may have been set to restrict access. This directory is usually located here: C:Inetpubwwwroot. If you want to remove any logon windows or have open access, go to this location and check the Everyone box; this will allow anyone to have free access to the directory.
From the perspective of the Windows 2000 machine itself, these Web server directories are just like any other directory on the server and can be configured separately.
This was first published in March 2007