As described in the directory schema, directory objects contain attributes, and those attributes function according to the values held by their properties. Every attribute contains the following three properties, which are particularly useful in ADSI support: Heuristics, ACL, and Description. The settings of these properties affect the behavior or use of the attribute on which they exist.
For example, if the Heuristics property on the Address-Home attribute of an object is an odd number, you know that its bit 0 has a value of 1. This value means that, when the object is replicated between sites, this Address-Home attribute is not replicated.
You can view the values of these properties as described in "Microsoft Exchange Directory Schema."