ORA-3136: Inbound Connection Timed Out

SYMPTOM
The database alert log reports an ORA-3136 error. Users may also complain that they are unable to log on, although a repeat attempt may prove successful.



ORACLE ERROR (oerr) OUTPUT
error- ora 3136

03136, 00000, "inbound connection timed out"

Cause:  Inbound connection was timed out by the server because user authentication was not completed within the given time specified by SQLNET.INBOUND_CONNECT_TIMEOUT or its default value

Action: 1) Check SQL*NET and RDBMS log for trace of suspicious connections.
        2) Configure SQL*NET with a proper inbound connect timeout value if necessary.

---CAUSE
A lag in the network or a layer between the database and the client is preventing the log on process completing within the allowed time.


---SOLUTION
By default, the SQLNET.INBOUND_CONNECT_TIMEOUT is set to 60 seconds.

Change the setting by adding the parameters SQLNET.INBOUND_CONNECT_TIMEOUT and INBOUND_CONNECT_TIMEOUT_<listener name> to the

 {{$ORACLE_HOME/network/admin/sqlnet.ora file on the database server.

Setting the above parameters to a value of 0 implies an infinite time out.

Alternatively, use the lsnrctl command and issue the following:

LSNRCTL> set inbound_connect_timeout=<value>

Before opting for the above parameter changes, confirm that any firewall activity or Network Address Transalation (NAT) that may be occuring beween the client and and the database are not the cause of latency which is exceeding the timeout threshold.