ORA-12170: TNS: Connect timeout occurred

Sometimes You can get “ORA-12170: TNS: Connect timeout occurred ” error.

ORA-12170: TNS:Connect timeout occurred

Details of error are as follows.

ORA-12170: TNS:Connect timeout occurred

Cause: The server shut down because connection establishment or communication with a client 
failed to complete within the allotted time interval. This may be a result of network or
 system delays; or this may indicate that a malicious client is trying to cause a 
Denial of Service attack on the server.

Action: If the error occurred because of a slow network or system, reconfigure one or all
 of the parameters SQLNET.INBOUND_CONNECT_TIMEOUT, SQLNET.SEND_TIMEOUT, SQLNET.RECV_TIMEOUT 
in sqlnet.ora to larger values. If a malicious client is suspected, use the address in 
sqlnet.log to identify the source and restrict access. Note that logged addresses may not
 be reliable as they can be forged (e.g. in TCP/IP).

To solve this error, add the following parameters to the sqlnet.ora file under $ORACLE_HOME/network/admin.

NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
SQLNET.INBOUND_CONNECT_TIMEOUT=360
SQLNET.RECV_TIMEOUT=10
SQLNET.SEND_TIMEOUT=10

And Check /etc/hosts file if it has DNS entry or not.

Do you want to learn more details about RMAN, then read the following articles.

https://ittutorial.org/rman-backup-restore-and-recovery-tutorials-for-beginners-in-the-oracle-database/