Oracle Database from 18c and above can authenticate and authorize Microsoft Active Directory users with the database directly without intermediate directories or Oracle Enterprise User Security (like Oracle EUS 12c).
This is a quick note about another tracing facility within Oracle. If you’re using Centrally Manager Users (CMU) with Active Directory you can enable a trace for the LDAP searches Oracle performs.
alter system set events=’trace[gdsi] disk low’;
alter system set events=’trace[gdsi] off’;
Try to connect with AD user, then go the directory containing the trace files and run the following:
grep -i kzlg *.trc