Alert Log Errors: 12170 TNS-12535/TNS-00505: Operation Timed Out

(Doc ID 1628949.1)

Last updated on SEPTEMBER 06, 2017

Applies to:

Oracle Net Services - Version 11.2.0.1 to 12.1.0.2 [Release 11.2 to 12.1]
Oracle Database - Standard Edition - Version 11.2.0.1 to 12.2.0.1 [Release 11.2 to 12.2]
Oracle Database - Enterprise Edition - Version 11.2.0.1 to 12.2.0.1 [Release 11.2 to 12.2]
Information in this document applies to any platform.

Symptoms

The following error is reported in the database alert log. 

***Note the "Client address" is posted within the error stack in this case.

Fatal NI connect error 12170.

VERSION INFORMATION:
TNS for 64-bit Windows: Version 11.2.0.3.0 - Production
Oracle Bequeath NT Protocol Adapter for 64-bit Windows: Version 11.2.0.3.0 - Production
Windows NT TCP/IP NT Protocol Adapter for 64-bit Windows: Version 11.2.0.3.0 - Production
Time: 22-FEB-2014 12:45:09
Tracing not turned on.
Tns error struct:
ns main err code: 12535

TNS-12535: TNS:operation timed out
ns secondary err code: 12560
nt main err code: 505

TNS-00505: Operation timed out
nt secondary err code: 60
nt OS err code: 0
***Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=XXX.XX.XXX.XXX)(PORT=45679))

  

The PORT field here is the ephemeral port assigned to the client for this connection. 
This does not correspond to the listener port.

 

Changes

No changes are necessary, but may have recently upgraded the database to 11g release 1 or higher, or installed a new Oracle11g database and they are now visible in the alert log.
Note: Prior to 11gR1 these same 'Fatal NI connect error 12170' are written to the sqlnet.log.   This document describes a problem that arises when a firewall exists between the client and the database server.

Cause

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