SSH

Use Xming on Windows to view X11 forwarded apps

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Recently, I have had a need to use Windows more frequently (Windows-only games and ActiveSync!), but still have a high demand on my network at the same time. I have sought to be able to combine the best of both worlds. I previously relied heavily on Web-based applications, but my favorite Web Development IDE was developed for Linux only. I had put up enough with the banalities of using WebMin and it’s built-in file editor. I have read about others having success running KDE apps on Windows, but since I had my Quanta already setup and configured, I looked for a way of just being able to access that. Honestly, I’m not very excited about using VNC over WiFi, even with high compression.

To my surprise, I found that Xming was specifically suited to my needs. It acts as an X11 server, allowing me to use it to display my X11 applications that I have forwarded through SSH. It works perfectly.

It took a little time for setting up, but if you have got PuTTY installed and working, sixty percent of the work is already done.

Below is a screen shot that shows my running Windows Vista desktop, programming in Quanta which is actually hosted on a server called A. This is connected through an SSH tunnel from my laptop to my C server using the Putty client. From the C server, I launch the Quanta program using another SSH connection to the A server. It looks just like the Quanta program is a native windows app on the local Windows Vista desktop. You’ll also notice I’ve got an xterm session open connected to server A in the background.

X11 Forwarding XMing Putty SSH

How To Add Programs To Your Startup In KDE

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I discovered the best way for me to mount my ssh shares via sshfs automatically when I log in. I add shares and folders from time to time, and I also wanted this technology to automatically be backed up for me, so I wanted the solution to lie inside my home folder. I did some research and learned that KDE has an Autostart folder. For KDE 3.x this is currently at ~/.kde/Autostart, and for KDE4 it is ~/.kde4 (which will eventually drop the 4). I’m already hosting my scripts in ~/bin, so I created a script in that folder to execute sshfs and create the mounts. I then created a link by right-dragging the icon in Konqueror from the ~/bin/ folder to ~/.kde/Autostart. This will work for any executable or script. Now my sshfs mounts automatically at login.

Problems with kdesu via SSH after Hardy Heron Upgrade

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I started encountering an error when using kdesu via SSH after Hardy Heron was installed. I’ve since upgraded to 8.04.1 as well and still am running into this bug.

X11 connection rejected because of wrong authentication.
kate: cannot connect to X server localhost:10.0

I know I’m not the only Kubuntu user, and there is proof I am not the only user encountering this error. I’ve been getting around it by using gksu which has no problems with my authentication. I suppose I could just alias kdesu and kdesudo (i tried it with no luck too!) to gksu, but I’d like to see an update fix this in the upcoming months. The nice fade effect of gksu is a welcome change sometimes.

SSH Denied Even Though The Keys Are Authorized

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I recently had to reinstall one of my servers. It was a pain. I didn’t have the partitions correct, so I lost my web install, and I hate how Ubuntu does not let us put /etc on a separate partition because of init. I struggled for a while with being forced to enter a password when using ssh connections to the re-installed. The output of ssh -vvv user@host indicated the keys were found and authorized, so I was stumped. I asked the North Texas Linux Users Group for some assistance and the first reply pointed me in the right direction. It turns out it was caused by incorrect permissions on my ssh files. To resolve, I used

cd ~
chmod go-w .ssh .ssh/authorized_key*

The OpenSSL Vulnerability

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I recently established my network to use SSH connections. My three Ubuntu systems I discovered were using weak keys that had been generated using the flawed packages. If you haven’t been paying attention, Canonical issued USN-612-1 on 5/13/2008. If you’re using keys that have been generated since September 2006, it’s likely that you need to regenerate all keys. If you have any doubts, I encourage you to regenerate all keys. It will affect any key used that was generated on a compromised system. The biggest trouble for me was getting OpenSSL and OpenSSH-server packages to update. I used the ssh-copy-id command to make it the process easy for me.

Browsing SCP and SSH

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Now that I’ve gotten my SSH server installed and working properly, I’ve found a need for some tools to work with that secure shell. KDE again comes to my rescue, and allows me to browse my remote secure shell connection right from inside of Konqueror. This makes it a breeze to copy and paste documents and folders between remote systems on my network. For this to work, the KIOSlave handler for the “fish” protocol is called upon. You can browse these remote systems by using this format for the Location box:


fish://user@remotesystem

This really cuts down on the time of using the command line to work with large groups of files. You can also use the same format within Qt applications’ dialog boxes, making it easy to work with files directly from inside of applications.