Access an Oracle instance by remote machine

It is possible to control access by IP address.
This can be controlled by setting the IP addresses to which access is allowed in the inbound rules of the security group set for the instance.
For more information, please refer to the following documents.
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Oracle.Resources.Shared.html
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.RDSSecurityGroups.html