| Platform SDK: Exchange Server |
Certain applications, such as a directory synchronization service, need to retrieve incremental changes from the Microsoft Exchange directory. This is done through the use of the following operational attributes, which exist on every object in the Microsoft Exchange directory:
| Attribute | Description |
|---|---|
| USN-Changed | An integer incremented by the Microsoft Exchange directory every time a modification is made to an object. (Deletions are treated as any other modification to the object.) |
| USN-Created | An integer that represents when an object was created in the Microsoft Exchange directory. |
| When-Changed | The UTC time when the object was changed. |
| When-Created | The UTC time when the object was created. |
By keeping track of the USN-Changed/USN-Created or When-Changed/When-Created attribute pairs, an application can identify changes that have occurred in the Microsoft Exchange directory since the last time it polled for changes. For more information on using these attributes to track changes, see Selecting Objects to Export and BatchExport.
By default, these attributes are available to authenticated users but not to anonymous users.