Posted by: Monish | June 9, 2009

WARNING: inbound connection timed out (ORA-3136)

What the error is telling you is that a connection attempt was made, but the session authentication was not provided before SQLNET.INBOUND_CONNECT_TIMEOUT seconds.

As far as adverse effects in the long run, you have a user or process that is unable to connect to the database. So someone is unhappy about the database/application.
In 10gR2, SQLNET.INBOUND_CONNECT_TIMEOUT the parameters were set to have a default of 60 (seconds).

Set the parameters SQLNET.INBOUND_CONNECT_TIMEOUT and INBOUND_CONNECT_TIMEOUT_listenername to 0 (indefinite).
Before setting SQLNET.INBOUND_CONNECT_TIMEOUT, verify that there is not a firewall or Network Address Translation (NAT) between the client and server. Those are common cause for ORA-3136.
The parameter is to be added in sqlnet.ora on the server, so wont require a shutdown.
and edit it at server side.


Reference: Oracle’s database forum and was provided by Eric Jenkinson:



  1. Monish,
    That was very helpful man.

  2. Thanks a lot Monish. Many days have i seen this error in my alert.log, but now i took action, found your topic, and understood the problem. I will do the changes right away, and follow it up to see how it goes.

    Thanks a bunch!

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