I installed Oracle Linux 21c on the remote machine, tested it in Linux shell, and it worked as expected (I can query the testing table I created). But I am stuck when trying to connect to the database from local SQL Developer client (Version

I downloaded 3 ODBC-related packages

  • instantclient-basic-windows.x64-
  • instantclient-sdk-windows.x64-
  • instantclient-odbc-windows.x64-

Above were unzipped and put in C:\oracle\instantclient_21_7. I also set up the DSN following https://windowsreport.com/install-oracle-odbc-driver-windows-10/.

On my laptop (Windows 10), I found ORACLE_HOME location and then created the TNSNAMES.ORA file following https://www.databasestar.com/tnsnames-ora-file/.

I launched SQL Developer, but the Database Connection panel showed:

No TNS entries found in {USER Home dir=C:\Users\xxxx, TNS_ADMIN=C:\oracle\instantclient_21_7, ORACLE_HOME=C:\Users\xxxx\AppData\Local\Temp\Temp2_WINDOWS.X64_193000_db_home.zip\network\admin}.

I tried to ignore above warning and created an Oracle Connection (Connection Type = TNS; Network Alias = net_service_name), clicked Test button, and I got an error:

Status: Failed: IO Error: The Network Adaptor could not establish the connection…

I couldn’t figure out what went wrong. Can anyone help please? Thanks in advance.

  • 1
    I don't think C:\Users\xxxx\AppData\Local\Temp\Temp2_WINDOWS.X64_193000_db_home.zip\network\admin is a valid folder for ORACLE_HOME Commented Nov 28, 2022 at 13:50
  • 1
    Where did you create the tnsnames.ora file? The folder you must put into TNS_ADMIN variable. Commented Nov 28, 2022 at 13:51
  • I opened the registry editor, selected ORACLE - KEY_OraDB19Home1, double clicked ORACLE_HOME reg_sz, and saw Value data = C:\Users\xxxx\AppData\Local\Temp\Temp2_WINDOWS.X64_193000_db_home.zip. This makes me think the path is where my ORACLE_HOME is located at... No? Or perhaps I should copy that .ora file to C:\oracle\instantclient_21_7 @WernfriedDomscheit?
    – geopark
    Commented Nov 28, 2022 at 21:49

1 Answer 1


Okay, I figured that out. sysdba is not a username, and I entered it when testing the connection. Certainly it wouldn't work. So, I created a user and used its username and password to connect to the remote DB and it worked.

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