Password change operations are normally treated as any other modification to an entry, so the update time is recorded in the
lastModified operational attribute. However, there can be times when the time of the last password change needs to be recorded separately, to make it easier to update passwords in Active Directory synchronization or to connect with other LDAP clients.
passwordTrackUpdateTime attribute within the password policy tells the server to record a timestamp for the last time that the password was updated for an entry. The password change time itself is stored as an operational attribute on the user entry,
pwdUpdateTime (which is separate from the
lastModified operational attributes).
attribute can be set as part of the global password policy or on a subtree or user-level policy, depending on what clients need to access the password change time. Setting password policies is described in Section 20.4, “Managing the Password Policy”