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Working on Enterprise Manager version at a client’s site, we would like to know if oracle database target in 18c version could be discovered and monitored, even if Enterprise Manager does not support Oracle 18c database targets.

Installing the agent 12c on the target host did not cause any problem, the oracle database 18c discovery ran successfully, but the database was seen as down in the Enterprise Manager console.

We tried several tricks without any positive results, but running the following command shows us that this was a connection problem:

[email protected]:/home/oracle/:> emctl getmetric agent DB18,oracle_database,Response
Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.
All rights reserved.
Failed to connect: java.sql.SQLException: 
ORA-28040: No matching authentication protocol,UNKNOWN,UNKNOWN,UNKNOWN

With Oracle 18c, the default value for SQLNET.ALLOWED_LOGON_VERSION parameter is 12, it means that database clients using pre-12c jdbc thin drivers cannot authenticate to 18c database servers.

The workaround is to add in the database server sqlnet.ora the following lines:


We restart the database and the agent, and the Oracle database 18c is displayed up and running in Enterprise Manager

Some more tests showed us that everything is working fine: incident management, performance, top activity ..aso

Nevertheless do not forget that oracle database target version 18c are not supported with Enterprise Manager I will recommand to use the last Enterprise Manager 13.3 last version in order to administer and monitor Oracle database 18c.

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Pierre Sicot
Pierre Sicot

Senior Consultant