howto reverse ssh tunnel

17 Dec 2006

howto reverse ssh tunnel

I recently (15-Dec-06) asked this question on the SLUG email list – thanks to everyone for all the replies I got, especially Dave, The Reverend, Michael K, Erik, Tongmaster, Alex S, Tigger, David K.

> Is there a way of configuring ssh, so that if someone ssh's into my
 > machine, I can connect back and get into their machine? (Linux to
 > Linux).
  • get him to ssh to you: ssh -R 2222:localhost:22 . Once he’s logged in, you can just ssh -p 2222 localhost. You may have trouble binding to ports 1024 or lower on the other side (which is why I used 2222 as an example), and you may have to enable an option in the sshd config of the other side. There’s an article on TechRepublic Setting up a reverse SSH tunnel.

  • once he’s ssh’d to me, I could get him to run apps and display on my machine ie type export, then run xterm & (or another program if it needed configuring)

  • him ssh’ing to me could be made easier by setting up an icon on their desktop that has ssh -R 1200:localhost:22 (install his public key on This can also be setup to access the ADSL modem: ssh -p 1234 -R 1201:, then browse localhost:1201 to get the modem setup page.

  • autossh is your friend. Just get it to set up permanent tunnels to your box, so you can always get through whenever you need to.

  • use OpenVPN or Hamachi to setup a VPN, then just ssh to the local vpn endpoint. Samba shares could also be setup across the vpn, allowing easy filesharing.

  • VNC can also be run over ssh – see VNC over SSH2 – A TightVNC Tutorial

  • if they run windows, I find logmein as the best remote support thing by far, penetrates nat etc pretty well. See here. Client runs on linux, but server (on target PC) is windows only unfortunately.


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