Step 1: Locate your exadata service
Step2: Get relevant database information: database unique name, vcn
Step 3: Create a public subnet in the VCN where the exadata is plugged in
Step 4: Create a bastion host on the public subnet of the VCN and grab the public IP and the private key file
Step 5: Security list in public subnet
Create or update security list on public subnet allowing ingress traffic on port 22 from the IP’s where the connection is going to be done and egress traffic to 0.0.0.0/0 on all ports
Step 6: Compose the service name for the SqlDeveloper connection
The service name is <database unique name>.<FQDN of the client subnet or host domain name> values obtained in step 2
Step 7: Grab the private IP of one of the database nodes
Step 8: Open a ssh tunnel from your local machine
ssh -i <private file of the bastion created in step 4> -N -L localhost:1521:<private IP of one database node obtained in step 7>:1521 opc@<public IP of the bastion host created in step 4>
Step 9: Test your connection
That’s all, hope it helps! 🙂
approaching off the bow 