Introduction to CDO for NTS

The Microsoft® CDO for NTS Library (Collaboration Data Objects for Windows NT® Server) version 1.2.1 exposes messaging objects for use by Microsoft® Visual Basic®, C/C++, Microsoft® Visual C++®, and Visual Basic Scripting Edition (VBScript) applications. The library allows server applications to send and receive messages without requiring access to the Microsoft® Exchange Server. You can create programmable messaging objects, then use their properties and methods for sending and receiving.

The CDO for NTS Library is intended to run on a Microsoft® Windows NT® Server, for example from Active Server Pages (ASP) script on a Microsoft® Internet Information Server (IIS). It is not intended to run on a client process, nor to access remote servers. No user dialog is invoked or supported by CDO for NTS.

The CDO for NTS Library uses SMTP (Simple Mail Transfer Protocol) to interface with a Microsoft® Windows NT® Server. SMTP is an Internet standard for electronic mail among clients having common access to a server for message storage. The SMTP protocol is defined in RFC 821, and its message format is defined in RFC 822.

The CDO for NTS Library interfaces with the SMTP (Simple Mail Transfer Protocol) server component of Microsoft® Internet Information Server (IIS) version 4.0 and later. The Session object uses the LogonSMTP method to differentiate the access from the Logon method of the the CDO Library, which interfaces with Microsoft® Exchange Server.

The SMTP server component of IIS has its own message store mechanism. The Inbox and Outbox are mapped to directories in the file system, and no other folders exist. Message transfer takes place in such a way that spooling appears instantaneous, so the Inbox has no incoming queue and the Outbox is always empty.

When CDO for NTS is running with IIS, the Inbox is a single common folder shared by all SMTP recipients and applications. It contains all messages received by IIS and destined for the local domains for which the SMTP server is configured. However, the incoming messages are segregated by the CDO for NTS Library according to their recipients. An application can only access messages destined for the address it used when it logged on.

When CDO for NTS is running with the Microsoft Exchange Server, the Inbox is the regular Inbox of the messaging user's mailbox. When CDO for NTS is running with Microsoft MCIS 2.0 Mail, the Inbox is the messaging user's Post Office Protocol version 3 (POP3) server Inbox.

Applications developed to run with CDO for NTS can also run with CDO for Exchange provided they do not use the NewMail object. Also, the Session object's LogonSMTP method should be changed to the CDO for Exchange session's Logon method.