Oracle SQL Developer: Test failed: The Network Adapter could not establish the connection?

Question

I\'m in real need of a help here. I setup a Oracle Database server on a VirtualBox VM and until yesterday everything seemed to work just fine. Today when I initiated the databas

Answer 1

I used to fight with VM networking settings such that my host could 'see' my vm, and vice versa.

I stopped worrying about this once i learned about port forwards.

You can simply tell VirtualBox to take traffic from your local port, say 1521, and forward that to the VM, say also 1521.

So when connecting to the VM from my host in SQL Developer, I can go to localhost:1521, and have my connection traffic go to the Oracle Listener on my Linux VBox image, listening on port 1521

Click on Port Forwarding

Add an entry for TCP 1521 and 1521

Then, in SQL Developer you can simply do this to connect to your DB on the VM