Add-In Object

The Add-In object represents a server application within the Microsoft Exchange Server directory. A server application uses its Add-In object as a place to store configuration information in the directory.

This object can also specify an Administrator extension DLL so that the server application can be configured and administrated using the Microsoft Exchange Server Administrator program. For more information on the Administrator program, see About Server Applications.

The Add-In object is very similar to a Mailbox-Agent object. The important difference is that no mailbox is associated with an Add-In object, which is intended to represent a server application that does not send or receive mail.

Add-In objects are stored in the Add-Ins container of the Microsoft Exchange Server directory. To associate an Administrator extension DLL with an Add-In object, the Add-In object's Extension-Name attribute must contain the name of an Admin-Extension object in the Add-Ins container of the directory. For more information on Administrator extension DLLs and the Add-Ins container, see Installing the Administrator Extension DLL.

Because Add-In objects appear to MAPI as messaging user objects, use the MAPI IMailUser interface to access an Add-In object.

For more information on accessing Add-In objects through MAPI and through directory access functions, see Adding an Object to the Directory.