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Asked: 2026-05-13T12:51:40+00:00

I’m trying to access an oracle database using using System.Data.OracleClient; from a console application,

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I’m trying to access an oracle database using 

using System.Data.OracleClient;

from a console application, accessing the database is fine. however from an ASP.NET web site i get the error:

ORA-12640: Authentication adapter initialization failed

I’ve googled around and found that changing sqlnet.ora file would solve the issue

//before
SQLNET.AUTHENTICATION_SERVICES= (NTS)
//after
SQLNET.AUTHENTICATION_SERVICES= (NONE)

Later I found another application on the same server, that uses other database of Oracle as well, is requiring the value of SQLNET.AUTHENTICATION_SERVICES to be “NTS”. This would cause my web site to fail accessing the database with the error ORA-12640. I have tried “ALL” as value but still it didn’t work.

How can I configure my website to access the oracle database while sqlnet.ora is configured as “SQLNET.AUTHENTICATION_SERVICES= (NTS)” ?

P.S. the website uses Windows Authentication and impersonate as follow:

<authentication mode="Windows"/>
<identity impersonate="true"/>
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1 Answer

  1. Editorial Team

    This looks like the multi-hop impersonation issue to me.

    If it’s an option for you, I suggest having your application run under a single identity when accessing the database (this should also allow connection pooling to occur as a beneficial side-effect).

    To do this, you would need to configure an app pool to run under an account that has access to Oracle. Once the application is running under that app pool, turn impersonation off in your application so that the database calls occur using the app pool identity.

    If you have to impersonate the calling users over the network, the method used will depend on your environment. For more information, see How to Use Impersonation and Delegation in ASP.NET 2.0.

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