ORA-12537: TNS:connection closed

I asked the user to send me more info and that's all he was able to provide.  I noticed in the sqlnet.ora the following :

Fatal NI connect error 12170.

  VERSION INFORMATION:
        TNS for IBM/AIX RISC System/6000: Version 10.2.0.3.0 - Production
        TCP/IP NT Protocol Adapter for IBM/AIX RISC System/6000: Version 10.2.0.3.0 - Production
        Oracle Bequeath NT Protocol Adapter for IBM/AIX RISC System/6000: Version 10.2.0.3.0 - Production
  Time: 30-NOV-2009 14:55:06
  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: 78
    nt OS err code: 0
  Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=120.12.214.2)(PORT=1521))

I restarted the listener and that didn't help either.  Then i logged into the database and noticed that there were 396 connections to the database and the processes parameter was set to 400.

I had to open emergency ticket to recycle the production database to change the value to 900 from 400 and restarted the database.

This fixed the problem and user was able to connect and i stopped seeing those errors.

Hope this helps.

Thanks,

ORA-12537 TNS:connection closed
Cause: Normal "end of file" condition has been reached; partner has disconnected.
Action: None needed; this is an information message.

Make sure you tnsnames.ora and listener.ora are all ok.  and if they are ...other then you max processes being reached, check your firewall and make sure the port is open and allowing connections to come in.

One last thing is to check your sqlnet.ora file to make sure all the parameters you set in there are all ok and that they work as they should because slight mistake in there can cause this as well.

hope this helps.

What to do with ORA-12537: TNS: connection closed error

ORA-12537

Also remember,  when you upgrade your databases, remember to update the listener as well.  

9i listener does not supports 10g database. Just use 10g listener. Allways the higher listener version supports lower DB versions but not the opposite .

Hope this helps.

Your network may or may not include all of these components.

Error Example

As an example, suppose that a user of a client application tries to establish a connection with a database server using Net8 and TCP/IP, and the user enters:

sqlplus scott/tiger@hrserver.world 

The SQL*Plus banner is displayed on the screen, and the following error is displayed:

ORA-12203: TNS:Unable to connect to destination

This message indicates that the connection to the server failed because the database could not be contacted. Although the application displays only a one-line error message, an error stack that is much more informative is recorded in the log file by the network layer. On the client-side, a log file called SQLNET.LOG, contains an error stack corresponding to the ORA-12203 error as follows:

Example 10-1 Typical Error Stack

***********************************************************

Fatal OSN connect error 12203, connecting to: 

(DESCRIPTION=(CONNECT_DATA=(SID=trace)(CID=(PROGRAM=)   

(HOST=lala)(USER=sviavant)))(ADDRESS_LIST=(ADDRESS=   

(PROTOCOL=ipc)(KEY=trace))(ADDRESS=(PROTOCOL=tcp)   (HOST=lala)(PORT=1521))))

VERSION INFORMATION:TNS for SunOS:Oracle Bequeath NT Protocol Adapter for SunOS:

Unix Domain Socket IPC NT Protocol Adaptor for SunOS: TCP/IP NT Protocol Adapter for SunOS:  

Tracing to file: /home/sviavant/trace_admin.trc  Tns error struct:    nr err code: 12203    

TNS-12203: TNS:unable to connect to destination    ns main err code: 12541    

TNS-12541: TNS:no listener    

ns secondary err code: 12560    

nt main err code: 511    

TNS-00511: No listener    

nt secondary err code: 61    

nt OS err code: 0