rdnType is an abstract attribute present on every object. The rdnType of an object is the RDN attribute of the object, that is, an ATTRTYP that identifies the attributeSchema object of the RDN attribute. rdnType is not represented in the schema and does not replicate in the normal way.
On an originating Add, the new object's rdnType is derived from the most specific structural object class of the new object.
On a replicated Add, rdnType is derived as follows: