Windows NT-initiated password synchronization works in a manner similar to host-initiated changes.
The Windows NT Account Synchronization service is installed on the Primary Domain Controller of the Windows NT domain (or domains) that support user accounts. An associated DLL, installed in the same location, receives notice of any password changes that arise in the Windows NT domain, regardless of how the change was initiated. The DLL sends Windows NT-initiated changes to the Windows NT Account Synchronization Service using encrypted RPC messages. Once the change is received, the service propagates the appropriate changes in all affected security domains.