Knowledge Consistency Checker (KCC)

A built-in service that runs on all domain controllers and automatically establishes connections between individual machines in the same site. These are known as Windows 2000 and Windows 2003 Directory Service connection objects. An administrator may establish additional connection objects or remove connection objects. At any point, however, where replication within a site becomes impossible or has a single point of failure, the KCC will step in and establish as many new connection objects as necessary to resume Active Directory replication.