To enable user principal name (UPN) logon for the Exchange 2000 Server version of Outlook Web Access (OWA), you must modify the Microsoft Internet Information Services (IIS) 5.0 properties as follows. On the Start menu, select Programs, Microsoft Exchange, System Manager. Locate the first Exchange server that you want to change, under any Administrative Groups that you have set up (Administrative Groups might not show up, depending on how System Manager is configured). Expand Protocols, HTTP, and Exchange Virtual Server. Right-click public and select Properties. Click the Access tab, click Authentication, and make sure that Basic authentication is the only authentication method selected. In the Default domain field, enter a backward slash character (\), as Figure A shows. Click OK twice to close the dialog boxes. Just as you did for public, repeat the process for Exchange (another virtual HTTP server). Just to make sure everything works, I prefer to reboot the server, then test the UPN logon.