I have SSH access to 'public' server, which is also the gateway to company network. There is another server in the network, where **local** Oracle Database server is running (There is no access from outside of this server, only localhost DB connections are accepted). And of course, I have another SSH access to this server.

Is there any way to join to this Oracle Database 11g Server from outside of the network ?
I am asking if there is something like ssh tunnel chain, and how i configure it. 
This can be usefull, for example, for TOAD for Oracle (ORACLE client).

**EDIT:** Here is image

![alt text](https://i.stack.imgur.com/vrfxt.png)
Thanks