Hi,
We are facing ORA-3136 error in the Alerg.log regularly. Here is the text from alert.log having the error.
-- Oracle database 10g (10.2.0.4), OS RH5
--Alertlog (accessed from OEM)
Mon Jan 30 10:11:41 2012
WARNING: inbound connection timed out (ORA-3136)
Tue Feb 7 10:39:45 2012
WARNING: inbound connection timed out (ORA-3136)
Tue Feb 7 17:34:52 2012
WARNING: inbound connection timed out (ORA-3136)
I have read a lot about this error from Oracle Support, and forums, and few info is like:
- The Oracle Net 10g parameters SQLNET.INBOUND_CONNECT_TIMEOUT and INBOUND_CONNECT_TIMEOUT_listenername default to 0 (indefinite) in 10.1. To address Denial of Service (DOS) issues, the parameters were set to have a default of 60 (seconds) from Oracle 10.2 onwards.
- In pre-11g releases, the server side sqlnet.log might contain additional information such as the address of the client whose connection failed along with an "ORA-12170: TNS:Connect timeout occurred" error. In version 10g and higher, the ORA-3136 warnings may appear in the alert.log.
WARNING: inbound connection timed out (ORA-3136)
- To protect both the listener and the database server, Oracle Corporation recommends setting INBOUND_CONNECT_TIMEOUT_listenername in combination with the SQLNET.INBOUND_CONNECT_TIMEOUT parameter.
- Also note that it is possible the reason the database is slow to authenticate, may be due to an overloaded Oracle database or node.
Supposed to be a possible solution :
- Set the parameters SQLNET.INBOUND_CONNECT_TIMEOUT and INBOUND_CONNECT_TIMEOUT_listenername to 0 (indefinite) or to an approprate value for the application yet still combat DOS attacks (120 for example).
These parameters are set on the SERVER side:
listener.ora: INBOUND_CONNECT_TIMEOUT_listenername
sqlnet.ora: SQLNET.INBOUND_CONNECT_TIMEOUT
Last year, we faced this error and we increased the value from 0 to 120 seconds for SQLNET.INBOUND_CONNECT_TIMEOUT, and then it did not come again. But this year it has coming almost frequently. I dont want to set its value to 0 of course. Any suggestion please?
Secondly, as from the above lines from alert.log, how can I find out that on 7th feb which user,host,etc. has connected to the DB server. I want all the information about clients who connected on 7th feb, especially at the error time, how please?
Thanks a lot.
Regards,,
Edited by: 910385 on Feb 8, 2012 6:38 AM