I can access a server A with SSH, and from there I can access server B, but I can't access B directly.
Is it possible to open a Nautilus folder in server B by clicking in
Connect to Server?
Yes that is possible. I have the following setup which works, but there might be easier ones.
In the file
You have to replace yourusername, hostname.of.sever.a and hostname.of.server.b
After that, you can (in Nautilus) go to Places->Connect to Server (its actually File->Connect to Server on my machine). And then enter
One thing to try is to add this to .ssh/config:
Once this is in place, you should be able to
When this is working, try Nautilus the way you describe and see if the proxying setup works for it as well.
An update on the previous answers: using netcat to forward the connection on the intermediate host works differently than ssh'ing directly, and will fail when you want to e.g. connect to a VNC server that is set to only accept local connections through a jumphost tunnel. In order for the connection to work exactly like a direct one, use the -W option present in newer versions of the client: