ORA-28040: No matching authentication protocol after Oracle 12c upgrade.

After Oracle 12c upgrade users started seeing below errors

ORA-28040: No matching authentication protocol

The main issue is older versions of drivers will not able to connect 12c server. In Oracle 12.1, the default value for the SQLNET.ALLOWED_LOGON_VERSION parameter is set to 11. This means that database clients using pre-11g drivers cannot authenticate to 12.1 database servers unless the SQLNET.ALLOWED_LOGON_VERSION parameter is set to the old default of 8 in $ORACLE_HOME/network/admin/sqlnet.ora

This can be done by using either :

SQLNET.ALLOWED_LOGON_VERSION_SERVER=8 (JDBC 10g drivers by default support this security version implementation)
OR
SQLNET.ALLOWED_LOGON_VERSION_SERVER=10 (If you had applied the patch 6779501, on JDBC 10.2.0.4 / 10.2.0.5, OR if the jar is bundled with Weblogic Server)
OR
The alternative is to leave the default SQLNET.ALLOWED_LOGON_VERSION_SERVER=11 on the database and upgrade the JDBC clients. You can download the JDBC 11g or 12c from http://www.oracle.com/technetwork/database/features/jdbc/index-091264.html

Note that SQLNET.ALLOWED_LOGON_VERSION has been deprecated in 12c.

Even after updating above values users might receive below error.
ORA-01017: invalid username/password: logon denied

In this case users need to add following parameter to sqlnet.ora
SQLNET.AUTHENTICATION_SERVICES = (NONE)

Also few users received ORA-28040 error when creating older version of databases (for ex: 10g) using DBCA

Reference :
Error "ORA-28040: No matching authentication protocol" When Using SQLNET.ALLOWED_LOGON_VERSION ( Doc ID 755605.1 )
JDBC Version 10.2.0.4 Produces ORA-28040 Connecting To Oracle 12c (12.1.0.2) Database ( Doc ID 2023160.1 ).

Thanks
Satishbabu Gunukula, Oracle ACE
https://oracleracexpert.com

Physical standby redo log must be renamed

When creating standby database using database duplication it completed but received below standby redo error. This error will not stop the replication but user don’t want to see these ORA- errors.

Finished recover at 2019-02-12:15:02:32
ORACLE error from auxiliary database: ORA-19527: physical standby redo log must be renamed
ORA-00312: online log 1 thread 1: '/oracle/redo1/ORCL/ ORCL _1A.rdo'

RMAN-05535: warning: All redo log files were not defined properly.
ORACLE error from auxiliary database: ORA-19527: physical standby redo log must be renamed
ORA-00312: online log 2 thread 1: '/oracle/redo1/ORCL/ORCL _2A.rdo'

Though this didn't stop the data guard replication, the customer wanted to get-rid the message. Starting with v10g, this was an expected behavior to improve the switchover and failover. With v10g, when MRP is started, it will attempt to clear the online log files.

If PRIMARY and STANDBY has the same directory structure then you will see these errors. This is an expected behavior when you don’t set log_file_name_convert parameter. You can get rid-off the error message just setup dummy value

SQL> ALTER SYSTEM SET log_file_name_convert='dummy','dummy';

You should not see ORA messages any more in the alert.log file.

Thanks
Satishbabu Gunukula, Oracle ACE
http://www.oracleracexpert.com