Sometimes You can get “ORA-12537: TNS:connection closed” error.
Details of error are as follows.
TNS-00584: Valid node checking configuration error Cause: Valid node checking specific Oracle Net configuration is invalid. Action: Ensure the hosts specified in the “invited_nodes” and “excluded_nodes” are valid. For further details, turn on tracing and reexecute the operation. (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=<hostname>)(PORT=1521))) TNS-12532: TNS:invalid argument TNS-12560: TNS:protocol adapter error TNS-502: Invalid argument 32-bit Windows Error: 515: Unknown error Error listening on: (ADDRESS=(PROTOCOL=TCP)(Host=<hostname>)(Port=1562)) TNS-12560: TNS:protocol adapter error TNS-00584: Valid node checking configuration error Connecting to (ADDRESS=(PROTOCOL=TCP)(Host=hostname)(Port=1521)) TNS-12537: TNS:connection closed TNS-12560: TNS:protocol adapter error TNS-00507: Connection closed
This error is related with the Permission or ownership or group permission, so check them if they are ok or not.
[oracle@msdbadm01 ~]$ ll $ORACLE_HOME/bin/oracle -rwsr-s--x. 1 oracle oinstall 239952653 Sep 11 20:36 /u01/app/oracle/product/12.1.2/dbhome_1/bin/oracle
Revoke the user execution permission from $ORACLE/bin/oracle as follows.
[oracle@msdbadm01 ~]$ chmod 6751 $ORACLE_HOME/bin/oracle [oracle@msdbadm01 ~]$ ll $ORACLE_HOME/bin/oracle -rwSr-s--x. 1 oracle oinstall 239952653 Sep 11 20:36 /u01/app/oracle/product/12.1.2/dbhome_1/bin/oracle
Or the second case of this error is as follows.
There is an invalid hostname in the TCP.INVITED_NODES list in the sqlnet.ora file.
Oracle no longer allows the listener to startup if an invalid hostname or ip address is specified in the invited_nodes list. The listener will not start if any of the hosts or ip addresses are note resolvable. The only solution to this issue is to ensure that all the hostnames and ip addresses in the invited nodes list are resolvable using ping or nslookup from the host where the listener is starting.
In some cases, the localhost might cause this behavior.
To solve this error, go to sqlnet.ora and check and fix the right INVITED_NODES IP as follows,
[oracle@msdbadm01 ~]$ cd $ORACLE_HOME/network/admin [oracle@msdbadm01 admin]$ vi sqlnet.ora TCP.INVITED_NODES=(localhost, <IP ADDRESS>) TCP.VALIDNODE_CHECKING = YES TCP.INVITED_NODES = (192.168.63.34,192.168.63.35,192.168.63.36)
Do you want to learn more details about RMAN, then read the following articles.