Are your firewalls silently killing idle database connections, leading to erratic application errors?
When you set SQLNET.EXPIRE_TIME to a value greater than , the Oracle Database server initiates a probe at the specified interval (in minutes). expire_time sqlnet.ora 19c
This can cause false disconnects during brief network hiccups. Stick to ≥5 minutes. check your sqlnet.ora .
If you face "ORA-03113: end-of-file on communication channel" errors due to idle connections, check your sqlnet.ora . expire_time sqlnet.ora 19c