In "Get Inside Active Directory Connector Synchronization," February 2006, InstantDoc ID 48589, I outline some of the mechanisms the Active Directory Connector (ADC) uses to synchronize hidden objects, distribution lists (DLs) with hidden membership, and connection agreement (CA) authentication and credential handling. Once you understand the ADC's internal operation and how it processes objects during synchronization, you can fine-tune the ADC to improve synchronization in your environment.
Determining Which Objects to Synchronize
The ADC uses update sequence numbers (USNs) to control synchronization between the Exchange Server 5.5 Directory Service (DS) and Active Directory (AD), much like Exchange 5.5 uses USNs to control intrasite and intersite replication. Each CA uses the value of two attributes—msExch-Server1HighestUSN and msExch-Server2HighestUSN—to control synchronization from AD to the DS and from the DS to AD, respectively. These attributes are properties of the CA. . . .

