By default VNC runs on port 5901. This port may not always be open for access. Vnc access maybe needed for GUI base work such as runInstaller, DBCA, DBUA etc. (there are other ways to get GUI to desktop, such as Xming). In situation where VNC port is not open it could be tunneled over SSH. This post shows how to use PuTTY for this effect.
1. Set the tunneling information before opening the ssh connection. Source port is the local listening port. In this case port 5999 has been chosen as the local listener port. Destination is a host:port combination. In this case the local host is the destination host and port is set 5901 which the remote vnc listening port.
2. Once Click add to make the tunneling take effect when ssh connection is established.
3.Establish the ssh connection.
4. Connect a vncviwer specifying the source port used earlier.
If the source port had been 5901 (the default vnc port) then the vncviwer connection could use the following