This post explains OWA Change Password functionality and questions about the features with Windows Server 2008.  The following is a quick synopsis of what you need to know to get this working the way you need it to. Previous versions of Exchange Server utilized the Change Password functionality for IIS 5 and 6 using the IISADMPWD virtual directory and a .DLL file on the server.  These configurations were discussed in the following KB articles:

FIX: You experience various problems when you use the Password Change pages in IIS 5.0
FIX: You experience various problems when you use the Password Change pages in IIS 6.0
Implementing the Change Password feature with Outlook Web Access

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