To determine the meaning of the Heuristics property and its implications for the attribute it applies to, you can examine its bits. They are interpreted as follows:
| Bit | Value | Significance |
| 0 |
0 1 |
Replication of attribute between sites No replication of attribute between sites |
| 1 |
0 1 |
Not accessible by anonymous clients through LDAP Accessible to both anonymous and authenticated LDAP clients |
| 2 |
0 1 |
Not accessible by authenticated clients through LDAP Accessible to authenticated clients but not to anonymous clients |
| 3 |
0 1 |
Not an operational attribute An operational attribute |
| 4 |
0 1 |
Not visible through the Administrator program, on the Attributes tab of the DS Site Configuration object (property page can be used to configure the non-operational attributes of the site) Visible through the Administrator program, on the Attributes tab of the DS Site Configuration object |
By taking note of the Heuristics property, you can determine the visibility of particular attributes. For example, a Heuristics value of 3 (bit 0 = 1 and bit 1 = 1) means that the attribute is visible by anonymous LDAP clients but is not replicated between sites.
A Heuristics value of 11 (bit 3 = 1 and bit 1 = 1 and bit 0 = 1) means that the attribute is an operational attribute; it is visible to authenticated LDAP clients and is not replicated between sites.
Note If both bit 1 = 1 and bit 2 = 1, the attribute is accessible to authenticated clients but not to anonymous clients.
Operational attributes (attributes with a Heuristics bit 3 set) are not visible through ADSI (though they are visible through ADO), even though it is possible to set their values through ADSI. To obtain the value of an operational attribute, use an ADO query as described in the example under ADSI Samples.
Caution Changing bit 0 of the Heuristics property could cause directory replication to stop. You should not change this bit of the Heuristics property of an attribute.