The 12537 is the Oracle error: $ oerr ora 12537 12537, 00000, "TNS:connection closed" // *Cause: "End of file" condition has been reached; partner has disconnected. // *Action: None needed; this is an information message. Is there a firewall between the Oracle instance and the cleints that are dying? Is dead connection detection configured? Does the Oracle username(s) profile have an idle timeout setting specified? ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Josh Collier Sent: Friday, June 03, 2011 1:58 PM To: oracle-l@xxxxxxxxxxxxx Subject: jdbc connection requests silently dying Hi, I have many silent connection attempts from jdbc failing silently. There is no error caught by the java code. I am finding very little information on Metalink. Have opened a ticket, traced the listener, changed inbound connection timout on both listener and jdbc string to no avail. The only thing I see in the alert log is this... Fri Jun 03 09:30:31 2011 *********************************************************************** Fatal NI connect error 12537, connecting to: (LOCAL=NO) VERSION INFORMATION: TNS for Solaris: Version 11.2.0.2.0 - Production Oracle Bequeath NT Protocol Adapter for Solaris: Version 11.2.0.2.0 - Production TCP/IP NT Protocol Adapter for Solaris: Version 11.2.0.2.0 - Production Time: 03-JUN-2011 09:30:31 Tracing not turned on. Tns error struct: ns main err code: 12537 TNS-12537: TNS:connection closed ns secondary err code: 12560 nt main err code: 0 nt secondary err code: 0 nt OS err code: 0 opiodr aborting process unknown ospid (7835) as a result of ORA-609 Also an individual trace file is generated. ORACLE_HOME = /dw01/app/oracle/product/11.2.0/dbhome_2 System name: SunOS Node name: whippet Release: 5.10 Version: Generic_142900-03 Machine: sun4u Instance name: DWDEV3 Redo thread mounted by this instance: 1 Oracle process number: 19 Unix process pid: 8564, image: oracle@whippet *** 2011-06-03 09:34:59.167 *** CLIENT ID:() 2011-06-03 09:34:59.167 *** SERVICE NAME:() 2011-06-03 09:34:59.167 *** MODULE NAME:() 2011-06-03 09:34:59.167 *** ACTION NAME:() 2011-06-03 09:34:59.167 opiino: Attach failed due to ORA-12537