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Old 01-21-2004, 02:33 AM   #1
ob1canob
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sshd behind a firewall


I have a computer on an edu network, which doesn't allow me to connect on any port (as far as I can tell) due to all those nasty Windows virii that were floating around. I want to be able to ssh into that box from an outside network. Is this feasible at all? I won't be able to poke a hole in the firewall, as I have no access to it. I do have access to dedicated boxes off the network.. here is what I was thinking, but I don't have the skills to implement it:

My computer's name: "MyEdu"
Off-site computer: "AtColo" (should be easy enough to remember, eh?)

I was thinking, MyEdu connects to AtColo via some method, and then AtColo listens on port 2222 for example. When someone connects to AtColo on port 2222, AtColo pipes the data to the connection that is already connected (MyEdu would always be connected to AtColo).

Any ideas to how this could be accomplished without programming knowledge?
 
Old 01-21-2004, 07:54 AM   #2
Crashed_Again
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If I understand the setup correctly I don't think its possible. The AtColo machine is outside of the network right? If this is true then trying to go through the AtColo machine to connect to the MyEdu machine inside the network would be like trying to connect to any other machine outside the network. The problem is that the schools router/firewall is not going to forward any requests into the network unless it is set up that way by the powers that be.
 
Old 01-21-2004, 08:21 AM   #3
jtshaw
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They have to let traffic through on some port.... you can bind SSH to any port you wish. Since 22 is obviously not allowed I would first try the standard ones like 20, 80, 153, 993, ect.

I hate it when people block port 22...
 
Old 01-21-2004, 02:03 PM   #4
stoffell
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vpn

how about creating a vpn connection between the 'internal' box and your publicly accessible box? maybe openvpn.sf.net can help you out..

good luck
 
Old 01-21-2004, 10:54 PM   #5
ob1canob
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To answer some of the questions..

-The edu blocks *all* incoming ports, (as far as I know), not just the standard ones. Is there a simple way to open all my ports.. and then use something like strobe from another network to see which, if any, are actually open?

-You're right, this does seem very not-possible.. the only way I can imagine this happening would be to connect to AtColo from MyEdu, and then AtColo would have to send the info back along that same pipe.. AtColo wouldn't be able to connect back to MyEdu because of the unfortunate port blocking status.

-About the vpn.. I checked out that website. Thanks, but it seems to me like I need to have ports open on both machines for it to work. Am I wrong?
 
Old 01-22-2004, 07:00 AM   #6
andrewlkho
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As said, there should be at least some ports open on your school firewall - such as 80. What you want to do is setup your outside box to listen for ssh connections on port 80, and then configure your client to use your school's proxy [if that's what you're using], and then go out to an ssh connection on port 80. Good luck with this - I've tried it, and can't get it to work, the reason being that my school's proxy actually monitor packets on port 80, and so if I try and ssh through there, then they'll reject my packets .
 
  


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