Oracle Connections

Enabling Remote Connections

On a Windows Server you will need to open the Windows Firewall so that remote users can access the database, if this is needed of course. The recommended approach is to permit two processes access through the firewall, which are:

  • Oracle_home\bin\oracle.exe - Oracle Database executable
  • Oracle_home\bin\tnslsnr.exe - Oracle Listener
For more details on this see Postinstallation Configuration Tasks on Windows.

Connection Issues

ORA-28040: No matching authentication protocol

This one puzzled me, however it turns out that Oracle 12c changed the default value of SQLNET.ALLOWED_LOGON_VERSION to 11, which means old JDBC thin drivers get the error message. So, you either need to update your "ojdbc" jar file or edit the sqlnet.ora file to include the following:
You may need to use SQLNET.ALLOWED_LOGON_VERSION_SERVER depending on what you are doing but SQLNET.ALLOWED_LOGON_VERSION was deprecated in Oracle 12c. See Parameters for the sqlnet.ora File for details.