Audit Log provides a log of those changes in LDAP Data Interchange Format form so that administrators can see exactly what changes were made. This information can be used for diagnostic purposes when investigating a problem, to help better understand the kinds of changes that an application might make in the directory, or to help collect information about changes for replay to an alternate repository.
The name "audit log" is a legacy term referring to its use in the Netscape Directory Server. It should not be confused with a log that could be used for security auditing, as it only records changes to directory data and does not keep track of things like successful or failed authentication attempts. However, in many cases, the combination of the content from the traditional access log and the audit log can be used to obtain this kind of information. If desired, an administrator could also provide a custom access logging implementation to keep track of any kind of desired information.