You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the "ISA Server 2006" entry in the Client Access Permissions topic.

1. In the ISA Server 2006 console, use the Publish Exchange Web Client Access wizard to publish Outlook Web App.
   
   
2. Configure ISA Server to authenticate users when they connect to the Outlook Web App virtual directories (optional).
   
   For more information about how to configure ISA Server, see ISA Server 2006.
   
   

If you've configured the ISA Server computer to authenticate users, it's recommended that you configure the Outlook Web App virtual directories to use either Integrated Windows authentication or Basic authentication, depending on which type of authentication is required by your organization. When you use Basic authentication or Integrated Windows authentication, users are prompted for their sign-in information only one time.

Note:
Integrated Windows authentication prohibits access to documents on Windows file shares or in Windows SharePoint Services document libraries from Outlook Web App. If you must access documents from Outlook Web App, you must use Basic authentication.

After you configure a reverse proxy server for Outlook Web App, you may also want toConfigure Outlook Web App Virtual Directories to Use SSL.