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johnny_bgoode
Asked: 2010-09-12 09:06:46 +0800 CST

NoMachine over SSH/Netcat proxy

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I am tunneling an nc connection to my target host (example.com) over an ssh connection to my gateway. Below is my .ssh/config setup for this connection:

Host target
Hostname example.com
HostKeyAlias target
ProxyCommand ssh me@gateway /bin/nc example.com 22

This is great and allows me to ssh to the target host in one step. What I would like to do is be able to tunnel an NX or VNC session over this connection.

Anyone know how this might be done?

ssh-tunnel nx

2 Answers

  1. Here's how a VNC session can be created over an ssh tunnel with a gateway hop in between the client and target machines:

    /etc/ssh/sshd_config (on target machine) must have these lines:

    X11Forwarding yes
XAuthLocation /usr/bin/xauth

    Your path to xauth may be different, but by default sshd looks in the wrong location so this value should be set.

    .ssh/config (on the client machine):

    Host example.com
Hostname foo.example.com
HostKeyAlias example.com
ProxyCommand ssh -t -C [email protected] /bin/nc %h 22

    Then from the client I can run 

    me@localhost$ ssh -X -C example.com
    This starts an X session on my client as well as an ssh connection to example.com. Now, just a couple more commands on the remote host to bring up VNC:

    [email protected]$ vncserver :n 
[email protected]$ vncviewer -encodings "copyrect tight zlib corre rre raw" :n

    In the above commands, :n is is the display number where you want to start vnc and the display where vncviewer should look for the vnc session. Since this looks like a local connection to VNC it is a good idea to specify some better encodings as vncviewer will default to raw, giving poor performance over the network.

    That's it!

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  2. Best Answer

    I think you should use port forwarding that SSH already can do:

    ssh -L 5900:example.com:5900 me@gateway

    This will forward port 5900 from your local machine to example.com through gateway. Now just "vncviewer localhost" from your local machine.

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