Re: ODBC-error 'ORA-12535: TNS:operation timed out' when trying to connect to Oracle 9.2.0

Am Tue, 22 Aug 2006 00:01:37 +0200 schrieb Sybrand Bakker <postbus_at_sybrandb.demon.nl>:

> On 21 Aug 2006 14:54:41 -0700, sirajka_at_hotmail.com wrote:
>
>> If you can tnsping successfully then it is not a firewall issue!
>
> Incorrect. If you can tnsping the only thing you know for certain is
> there is a listener running on that port.
> Sqlnet by default uses 2 (*two*) ports, one fixed and one random.
>
> --
> Sybrand Bakker, Senior Oracle DBA

Thanks for your answer, exactly that was the problem in my case.

There was a firewall on the server that blocked all ports except port 1521. But communication with the listener will only be initiated through port 1521. Afterwards communication is switched to other not-predictable ports, so all answer-attempts were blocked by the firewall and therefore there was never ever any reaction from the oracle server till the timeout occured.

This can be solved by adding a registry entry on the server: Under HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\HOME0, an entry USE_SHARED_SOCKET (Type Reg_SZ) has to be added and set to TRUE. Then all inside/outside connections will be made only via the predefined listener port (1521, if not changed otherwise).

Afterwards communication operated flawlessly. Received on Mon Aug 28 2006 - 04:29:16 CDT