Last updated on AUGUST 19, 2017
Applies to:Oracle Net Services - Version 220.127.116.11 and later
Information in this document applies to any platform.
Following a recent database upgrade to 12.2, an 11gR2 client might suddenly start to fail to connect to the database with an error ORA-28040.
This is a common problem with 12c and newer instances. In this case, the ORA-28040 is easily resolved with the server side
sqlnet.ora file setting for SQLNET.ALLOWED_LOGON_VERSION_SERVER=10 or 11.
It's important to note that the default setting for this parameter at the 12.2 server has been changed from 11 in version 12.1.
The default in version 12.2 is now '12'. So a client that might have been able to connect to 12.1 may start to fail after an
upgrade to 12.2.
However, once the ORA-28040 error is cleared, the client still cannot connect and a persistent ORA-1017 is returned.
This is despite full confidence in the credentials being supplied by the user.
ORA-28040: No matching authentication protocol
ORA-01017: invalid username/password
This is likely a new installation of version 12.2 Oracle database.
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