Re: [JSch-users] multi-stage ssh tunneling

[Paul B. <bem...@ya...>]

This is very clever... very clever indeed.

This will also work for more than 2 legs, and it keeps all password management on
the local client machine...  I can execute all tunneling from jsch, without having
to establish follow on tunnels using exec'd ssh commands.

I'm going to give this a try!

paul

--- leapingbytes <lea...@le...> wrote:

> On fist "leg" tunnel "ssh" connection to second "leg" server like this:
> 
> 	ssh -L 60022: web12.nit:22 bemowski@jump42 &
> 	ssh -p 60022 -L 8080:localhost:8080 bemowski@localhost
> 
> This way, you can make n-jumps without much problem.
> 
> Andrei Tchijov
> Leaping Bytes, LLC
> 
>       web: www.leapingbytes.com
>     email: an...@le...
>        AIM: leapingbytes
> Google: lea...@gm...
>        ICQ: 151229319
> 
> 
> P.S. Little bit of shameless self promotion.  If you are using Mac OS  
> X, you may want to take a look at http://www.leapingbytes.com/ 
> amostvpn.  This is SSH Tunnel manager which can do multi-jump tunnels  
> and much more.
> 
> On Nov 16, 2006, at 9:12 AM, Paul Bemowski wrote:
> 
> > Hello -
> >
> > I'm new to jsch, as well as the mailing list.  I've been working  
> > with jsch for about
> > 2 days, and I must say I'm very impressed with the quality and  
> > scope of the
> > application.  With the examples, I was able to have it up and  
> > running (tunneling) in
> > a few minutes.
> >
> > I do have a question however.  I often need multi-stage tunnels,  
> > which is in part
> > what I am trying to automate with jsch.  Using standard ssh  
> > commands, I'd do
> > something like this:
> >
> > ssh -t -g \
> >   -L 8080:localhost:8044 \
> > bemowski@jump42 \
> > ssh -t -g \
> >   -L 8044:localhost:8080 \
> > bem...@we...t
> >
> > I do know that I could port forward through the jump42 box to port  
> > 8080 of web12 -
> > but there is a firewall between them that blocks everything but  
> > port 22.
> >
> > So - I can see very clearly how to use the API to create the first  
> > port forwarding.
> > The question is how to use the API to execute the second ssh  
> > command as in the first
> > ssh session, and provide the necessary credentials... I've tried by  
> > creating a
> > ChannelExec and issuing the second ssh command, and using the  
> > streams to convey the
> > passwords - but that does not work.  I've also tried using the  
> > ChannelShell and
> > using that to execute the second ssh command via the output stream.
> >
> > Both methods have failed.  i've tried numberous stream readers and  
> > writers...
> > nothing is working.
> >
> > I've searched the archives of this list as much as possible, but I  
> > don't see
> > anything relating to this topic.
> >
> > Could someone perhaps give me a hint - or push me in the right  
> > direction?  Is this
> > multi-stage tunnel possible.  Also, the next question is, can I do  
> > a 3 stage tunnel
> > rather than 2 stage?  I'd imagine that once I get the second ssh  
> > command to work,
> > i'd repeat the process for the third...
> >
> > Thanks,
> > Paul
> >
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