Infrastructure at your Service

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.


  • David says:

    Great article. I learned something new. I have a oem 12c5 environment and wanted to monitor and manage a 12.2 DataGuard environment. I was able to discover the environment, but just as had happened with the client case you reported above, the database status showed as down. When I get back home from vacation, I’m going to try the sqlnet.ora entries you listed above. Thanks for this post – David

  • David says:

    Great post. I ran nto the same issue, but experienced a different result. I have a OEM environment with a Repository. I have a target database that’s I successfully discovered and promoted the DB, but the status shows as Down. I added the two sqlnet.ora statements you recommended, but the DB still shows as Down and now I get the following error from emctl getmetric agent PRIMEDB.localdomain,oracle_database,Response:
    Oracle Enterprise Manager Cloud Control 12c Release 5
    Copyright (c) 1996, 2015 Oracle Corporation. All rights reserved.
    0,UNKNOWN,Failed to connect: java.sql.SQLException: ORA-01017: invalid username/password; logon denied

    Any idea why this is happening?

  • David says:

    Never mind. I figured it out.

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Oracle Team
Oracle Team