Yesterday I wrote about using SSH to securely connect to a Mac from a Windows PC. At the time, I suggested that the advice should be equally applicable to a Linux system, or even to a Windows Server with an SSH server installed and I’ve since tested it with a Linux machine (running Fedora Core 5).

The Linux process is almost identical to my original post for Mac OS X, except that:

• The sshd_config file is found in /etc/ssh.
• SSH is enabled in the firewall using the system-config-securitylevel command.
• The SSH deamon is restarted using the service sshd restart command.
• GNOME includes a VNC server called vino, which needs to be enabled (users of other graphical environments will need to choose an alternative VNC server).

(Also… RTFM… I spent a lot of time trying to work out why I couldn’t connect, only to find that I’d neglected to place the public key in ~/.ssh/authorized_keys).

Falko Timme has written an excellent tutorial on key-based SSH logins with PuTTY which outlines all the key steps (in fact, if I knew that existed then I wouldn’t have spent so much time writing up the process here!) but Jeremy Mates’ OpenSSH public key authentication article includes a useful troubleshooting guide for public key authentication problems.

VNC is all very well for forwarding the entire desktop, but X11 forwarding can be used to run individual X applications on the Windows machine. Because Microsoft Windows doesn’t include an X Window server, it is necessary to download an X11 port for Windows – I used XMing. Once XMing (and the XMing fonts) were installed and running, I edited my PuTTY connection to enable X11 forwarding and ensured that the sshd_config file on the Linux box included X11Forwarding yes (that was the default on my Fedora Core 5 installation) and could launch an xapplication from within the PuTTY terminal window with xapplicationname & (e.g. xeyes &) (I found this information at the Linux Documentation Project). XEyes is nothing special, so how about running a Linux application on the Windows desktop… try mozilla & or gimp & – it feels “wrong” but it’s also pretty impressive and oh so “right” at the same time!