Tests the connection between the domain controller on which you run the command and the source domain controller. (This parameter is used for the CheckSecurityError test.) SourceDomainController is the DNS name, NetBIOS name, or distinguished name of a real or potential server that will be the source domain controller for replication, as represented by a real or potential connection object.
This existed in NT 4.0 Domain Controllers. So this switch does not apply to your enviroment and I am not 100% sure it would apply to anyone anymore since we are now on Server 2012 (5 verisons since NT 4.0)
From http://technet.microsoft.com/en-us/library/cc731935(v=ws.10).aspx