The dynamic-link libraries for CDO (CDO.DLL) and CDO Rendering (CDOHTML.DLL) are MAPI client object libraries. As such, they require MAPI (the version of MAPI32.DLL installed with Microsoft® Exchange Server version 5.0, or above) and service providers — for example, the same service providers as with Microsoft Exchange Server. CDOHTML.DLL and CDO.DLL are included with Microsoft Exchange Server and are installed on the server when the installation option Active Server Components is selected.
You can also use CDO (CDO.DLL only, not CDOHTML.DLL) after installing the Windows Messaging client included with Microsoft® Windows® 95 and Microsoft® Windows NT® version 4.0. CDO Rendering (CDOHTML.DLL) is intended for server-side use only.
Although CDO works with Microsoft® Outlook™, CDO.DLL is not installed with the Outlook setup program. You can set up CDO after setting up Microsoft Outlook by installing the library on its own or by installing the Microsoft Exchange Server 5.0 client. (You can install the CDO libraries independently by copying them from the installation CD-ROM to your computer's system directory.)