[Gllug] how do I ssh between different machines both behind 2 separate NA Ted firewalls

[Paul Nasrat]

On Mon, Mar 24, 2003 at 02:41:06PM -0000, James Bailey wrote:
> Hi,
> 
> I have been asked to make ssh connections between various machines which
> will be behind different NATed firewalls.  

Can you access any machines via ssh?  If so you can do ssh tunneling

>From your.workstation.example.com

ssh -l username -i ~username/.ssh/id_dsa -N -L \
    2222:hidden-1.example.com:22 opentossh.example.com

> Anyone out there come across this kind of problem before and found a
> suitable solution.  Links to suitable RTFMs appreciated if I have missed
> something obvious.

If you don't have any access to the servers but the firewall allows
outbound traffic to port 22 of a machine on your network you can reverse
tunnel back to your machine

>From hidden-1.example.com

ssh -l sshuser -i ~username/.ssh/id_dsa -N -R \
    2222:hidden-1.example.com:22 remote.example.com

Then you can ssh from your.workstation.example.com to
remote.example.com:2222

Now if you don't have access you may have to get someone to do this,
then you can do a key exchange and get it to do on boot

As you don't have firewall access I'm guessing VPN's are a no go.

The other options may require making use of openssh's ProxyCommand and
something like httptunnel [1] or a SOCKS [2] if there is a remote
connection to a proxy.  It really depends what services you can get at
via the remote firewall 

Just found this site which may be of interest:

http://www.jfranken.de/homepages/johannes/vortraege/ssh3.en.html

Paul Nasrat 
[1] http://www.nocrew.org/software/httptunnel.html
[2] http://www.imasy.or.jp/~gotoh/ssh/connect.html
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