Common listening errors in ALERT logs 2: troubleshooting of ORA-3136 errors, alertora-3136

Common listening errors in ALERT logs 2: troubleshooting of ORA-3136 errors, alertora-3136
This problem has recently been encountered in multiple large systems. Generally, it can be ignored if the client does not reflect exceptions.
If you encounter ORA-12170: TNS: Connect timeout occurred when logging on to the client, you can refer to the http://blog.csdn.net/haibusuanyun/article/details/14517211#t12
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Reference MOS documents include:
Troubleshooting Guide for TNS-12535 or ORA-12535 or ORA-12170 Errors (Document ID 119706.1)
Troubleshooting Guide ORA-609: Opiodr aborting process unknown ospid (Documentation ID 1121357.1)
Troubleshooting Guide ORA-3136: WARNING Inbound Connection Timed Out (Doc ID 465043.1)

Alert. log shows ORA-609 with TNS-12537: TNS: connection closed (Document ID 1538717.1)
11g: ORA-609 TNS-12537 and TNS-12547 or TNS-12170 in 11g Alert. log (Document ID 1116960.1)
Fatal NI Connect Error 12170, 'tns-12535: TNS: operation timed out 'reported in 11g Alert Log (Document ID 1286376.1)
Alert Log Errors: 12170 TNS-12535/TNS-00505: Operation Timed Out (Document ID 1628949.1)
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Classify these problems as follows:

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Troubleshooting steps for ORA-3136: WARNING Inbound Connection Timed Out error:


This error occurs because the client cannot complete user verification within the specified time range of SQLNET. INBOUND_CONNECT_TIMEOUT.
There may also be a ORA-12170 or TNS-12535 in the sqlnet. log that contains client-related information.
SQLNET. INBOUND_CONNECT_TIMEOUT starts from 10.2.0.1. The default value is 60 seconds. If the client cannot complete login authentication within 60 seconds, the client connection is aborted and ALERT reports this error.
---- This is mainly used to prevent DoS attacks.


This error may be caused:
1. DoS attacks and a large number of malicious connections. It is correct to report an error and terminate the client connection.
2. The connection is normal, but the login verification is not completed within 60 seconds after SQLNET. INBOUND_CONNECT_TIMEOUT value =.
3. High database server load, similar to HANG.


Troubleshooting:
1. Connect to the database locally and test whether the database is HANG
2. check whether there are internal errors such as 600/7445 in DB.
3. Network Problems

Solution:
It is recommended that the sqlnet. ora -- DATABASE value be greater than listener. ora -- LISTENER.
For example:
Sqlnet. ora
SQLNET. INBOUND_CONNECT_TIMEOUT = 120

Listener. ora
INBOUND_CONNECT_TIMEOUT_LISTENER = 110

Verification:
LSNRCTL> show inbound_connect_timeout

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