My developers have been developing Web sites on Windows 2000 Professional (IIS 5.0) machines. I recently upgraded some of these workstations to Windows XP Professional Edition (IIS 5.1), and now any code that uses Collaboration Data Objects for Windows NT Server (CDONTS) for delivering SMTP messages from a Web site fails to work. What's different in XP that causes CDONTS to fail?

With CDONTS, you can easily create a script that uses the Microsoft SMTP Service in IIS to send email messages. (For more information about the SMTP Service, see Tim Huckaby, "Sending Email from IIS," March 2002, InstantDoc ID 23811.) CDONTS and the SMTP Service have worked well in both IIS 5.0 and IIS 4.0, but Microsoft seems to be trying to move developers to the more powerful Collaboration Data Objects for Windows 2000 (CDOSYS) objects. (For more information about CDONTS and CDOSYS, see the Microsoft article "INFO: Relationship Between 1.x CDO Libraries and CDOSYS.DLL" at http://support.microsoft.com/default.aspx?scid=kb;enus;q195683.) Microsoft doesn't include CDONTS in XP or Windows .NET Server (formerly code-named Whistler), so code that invokes CDONTS objects will fail. To make your code CDOSYS-compatible, you'll have to tweak it. The Microsoft Developer Network (MSDN) provides useful VBScript code for using CDOSYS to send SMTP messages. You can get the script from http://msdn.microsoft.com/library/enus/wss/wss/_clb_sending_a_web_page_by_smtp_mail_using_cdosys_vbs.asp.