How to solve ora 28040 error: no matching authentication protocol SQL Server 2012?

Juan Manuel Eugenio Popoca 96 Reputation points

Hello, I have the next problem.

In SSMS 2012 I had an oracle 11g linked server, recently this oracle DB has been migrated to oracle 19c, in the server where I'm running SQL Server we installed the Oracle 19c client, so now we have two oracle clients installed, the 11g and the 19c, but now that I try to link this new DB in SSMS it shows the ora 28040 error:


I have read that this could be solved configuring the sqlnet.ora file in the destination server adding the SQLNET.ALLOWED_LOGON_VERSION=8, but I also read that this is more like a workaround and the solution would be to install the new client (the 19c in this case), but now, since I already have installed the 19c client I would like to know how to link this serverver without configuring the sqlnet.ora file in the destination server.

This are the linked server properties

Thank you in advice

SQL Server
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  1. Tom Phillips 17,686 Reputation points

    That error is an Oracle error. You would probably get a better answer from an Oracle forum.

    However, online answers to this question seem to indicate the Oracle JDBC driver needs to be updated in order to connect to v19.

  2. Erland Sommarskog 92,956 Reputation points

    SSMS is not using any provider - SQL Server is. SSMS is only the frontend tool.

    I don't know much about the Oracle providers, but if the two versions have the same name and GUID, you may need to uninstall the old version before you slap on the new one.

  3. Seeya Xi-MSFT 16,406 Reputation points

    Hi @Juan Manuel Eugenio Popoca ,

    This is a article for those who encounter similar problems to refer:

    Best regards,

    If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
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  4. Olaf Helper 36,006 Reputation points

    so now we have two oracle clients installed, the 11g

    You may have, but you use OleDB, that's a ActiveX (COM) provider, and only one can be registered on a machine; wellcome to DLL hell:

    You have to ensure that the new OleDB for Ora 19c is registered.

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  5. Tom Phillips 17,686 Reputation points

    The error you are receiving indicates the driver you have installed on the SQL Server is not compatible with the Oracle server you are connecting too. SQL Server uses the Oracle client installed on the server. You need to upgrade the client on the server to a client compatible with Oracle 19c.

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