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Windows: Intermittent ORA-12560 Reported for Remote Connections or Over Oracle Net (Doc ID 859058.1)

Last updated on JANUARY 08, 2020

Applies to:

Oracle Net Services - Version to [Release 10.2 to 11.2]
Microsoft Windows x64 (64-bit) - Version: 2008 R2
Microsoft Windows (32-bit)
Microsoft Windows
Client connections from Windows Platform


Oracle client connections randomly fails with ORA-12560. At the same time other clients are connecting fine to the same server / RDBMS.

Other sessions on the same client, opened before or after the connection failure can still work.

Oracle Net Client trace show the connection failing, is not getting off the client.

Oracle Net is attempting to use the socket (824) allocated to the connection and this errors with nt[1]=65, which is WSAEHOSTUNREACH 65 10065
No route to host. A socket operation was attempted to an unreachable host.
This happens before connection handshake with the TNS listener / RDBMS is even attempted.



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