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IO Error: the network adapter could not establish the connection - from remote PC only

Dear all,

I am not an oracle export so please apologize some bad wording. Hope the category is not too bad...

We are running an oracle 18.4 XE data base.

Right from that server were the DB is running i can connect via SQL developer and some other java app without issues.

But if I try to connect to that DB from my Windows 10 PC via network the SQL-Developer and same java app reports the "IO Error: the network adapter could not establish the connection".

The SQL developer on my Windows 10 PC is working normal if I connect to a complete different Oracle DB. So I would not see any local issues on that Windows 10 PC, firewall or blocked ports.

I tried to google a lot but did not find a proper suggest fix that issue.

Thanks for any help.



  • Jason_(A_Non)
    Jason_(A_Non) Member Posts: 2,106 Silver Trophy

    Long ago, there used to be a General Database Discussion, but that was before the community was migrated onto the current forum software and I'm not sure where that group went to. I may not have the answers but I'll ask some questions that might help you or someone else.

    So you have your local machine and your remote machine. So when you are on that remote machine, either directly or via RDP from your local machine, using SQL Developer on it will successfully connect to the DB on the same machine.

    From your local machine, you can successfully use SQL Developer to connect to an Oracle DB on a different remote system.

    When you try to use SQL Developer to connect to the DB on this one specific system, you encounter the error.

    So can anyone else connect to the DB on this specific system?

    Is Oracle listening on port 1521 (assuming standard port) on the remote system?

    Have you tried to use tnsping from your local system to reach the remote system?

    Are you using Instant Client on your local machine or JDBC or how are the connections from your system to the remote system defined?

  • User_NAE5A
    User_NAE5A Member Posts: 2 Green Ribbon

    Hello Jason,

    Thanks for your reply. Your additional queries brought me to the solution.

    The windows firewall on the machine with the oracle DB blocked the connection´from remote. I disabled it, and the connections worked. So i know now were to check.