Putty SSH Multi-hop X11 Forwarding

Wall of Fire Card

If your remote computer is sitting behind a firewall, and you need to go through a sshgateway server, you can use a simple multi-hop instead of a tunnel. e.g.
Home_Computer-> SSH_Gateway -> Work_Computer

With plink on the command line:

plink -t -X -A username@SSH_Gateway ssh -X -A username@work_computer 

Or in Putty:

Hostname: SSH_Gateway
Data -> Auto-login username: username (for ssh gateway)
SSH -> Remote Command:

 ssh -X -A username@work_computer

Auth -> Check “Allow agent forwarding” if you are using Pageant
X11 -> Check “Enable X11 forwarding” if you want it.

What the options mean:
-t enable pty allocation (used so you can do the second ssh from gateway to the work computer)
-A agent forwarding (only needed if you are using Pageant or another key agent)
-X enable X11 forwarding (only needed if you want to send X11 back to your home computer)

If you want X11 on Windows, setup Xming and Bob’s your Uncle.

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2 Responses to Putty SSH Multi-hop X11 Forwarding

  1. Seth Gilchrist says:

    Thanks for this excellent, concise post. I think the second example should read:
    ssh -X -A username@work_computer
    (with a capital ‘X’)
    I directed one of our users here, and he’s now convinced we need to recompile sshd because his X forwarding isn’t working.

  2. Sam says:

    You’re correct, fixed it.

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