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I have a domain that i bought from DynDNS. I pointed the domain at my ip adress so i can run servers. The problem I have is that I don't live near the server computer... Can I use an ssh tunnel? As I understand it, this will let me have access to my servers. I want the remote computer to direct traffic from port 8080 over the ssh tunnel to the ssh client, being my laptop's port 80. Is this possible?

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up vote 4 down vote accepted

This is actually pretty easy to accomplish, even though it's somewhat buried in the ssh documentation. Assuming OpenSSH, the basic syntax is as follows:

ssh -R 8080:localhost:80 -N username@your-server.dyndns.org

This will open a listening socket on port 8080 of your-server.dyndns.org, and any connections that are made onto your-server.dyndns.org:8080 will be forwarded over the SSH tunnel to the computer which has opened that SSH connection, and from there will be directed to localhost:80.

The -N option instructs SSH not to open a shell or whatever, just to establish the port forwarding, so you can send it into the background and leave it running.

Putty uses pretty much the same syntax, but wrapped into some sort of GUI. The principle is the same though.

But be careful in what you do. Since you're essentially funneling external traffic into your network, you are pushing a hole in your network's firewall. If it is not your network, your admin may object to this and take you responsible—usually there is a reason why you are not allowed certain kinds of traffic.

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no its just my home network but and im using ssh on a mac which i think is an implimentation of openssh code but going to mysite.com:8080 is giving an error of a nonexistant server, i check with telnet and it says there nothing –  Trevor Rudolph Dec 10 '12 at 2:06
    
but i just checked on the remote computer and it says this, tcp 0 0 127.0.0.1:8080 0.0.0.0:* LISTEN 0 14875755 - –  Trevor Rudolph Dec 10 '12 at 2:07
    
How exactly does your commandline look like? The localhost:80 part is the crucial thing here—it has to exist from the point of view of your local computer, not of the remote one, otherwise you'll get errors like the above. –  Vucar Timnärakrul Dec 10 '12 at 2:15
    
yea i wrote in 127.0.0.1 instead, ill try localhost... –  Trevor Rudolph Dec 10 '12 at 2:25
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It seems as if the remote side only binds on localhost instead of to all interfaces. Try doing it this way: ssh -R *:8080:localhost:80 -N ..., that way you're telling it to listen on port 8080 on all network interfaces that are in reach. The line above worked on my PC, but maybe the Mac version of ssh works slightly differently. –  Vucar Timnärakrul Dec 10 '12 at 2:28

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