My current DSL provider , has a 6in4 tunnel which I have been using and wanted to have a simple script to create a firewall on Ipv6. I searched quite a bit on the internet but could not readily find scripts which would work in a 6in4 tunnel mode until i found the link http://www.tunnelbroker.net/forums/index.php?PHPSESSID=702ecd4f548eb60461a09b7187922d0d&topic=1488.0

I modified the above link so that I could use it for my setup where I only have one machine that is my laptop where the 6in4 tunnel is setup. Hope this helps someone.

posted at: 19:15 | category: /linux | permanent link to this entry | Donate via Bitcoin
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As Im playing with various versions of debian I wanted to cache all the packages to reduce the load on debian servers.
So I installed apt-cacher by following the instructions at http://lgallardo.com/en/2009/11/10/mirror-interno-con-apt-cacher/
Now the problem is that I ran into this weird error "Unable to create libcurl socket" and it just wouldnt work.
In any case after re-reading the above article multiple times figured out that I had not set the path_map in my apt-cacher.conf file.
Essentially the path_map parameter substitutes the value of the URL during its own run-time so that it knows where to fetch the packages which it does not have in its own cache.
In any case a better error message would have potentially helped debug this .

posted at: 06:37 | category: /linux | permanent link to this entry | Donate via Bitcoin
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I wanted the stability of debian squeeze but at the same time just try out some of the new latest applications in Knoppix 7.0.4
These instructions are fairly generic and should be applicable for Ubuntu or any other GNU/Linux distribution.
You will need approximately 15GB of free space apart from the ISO image which will take about 4GB.

On my debian squeeze machine i had to install cloop-utils
aptitude install cloop-utils
tried to build the cloop module in debian squeeze but could not due to a potential defect
So then i thought about just getting the Knoppix environment into Squashfs
I mounted the KNOPPIX_V7.0.4DVD-2012-08-20-EN.iso using
mount -t auto -o loop  KNOPPIX_V7.0.4DVD-2012-08-20-EN.iso /mnt/iso
Then go to folder /mnt/iso/KNOPPIX there you will find a huge ~ 3.8GB file called KNOPPIX

The command documented @ knoppix did not work for me as it seemed like it was just some error in passing arugments it would not even process the command.
So i used the following command
extract_compressed_fs /mnt/iso/KNOPPIX/KNOPPIX - > knoppixcloop
File knoppixcloop was about 9 gb so make sure where you redirect this file that it has enough space.I dont know if this entire step is needed or not.

Now reboot into knoppix so that we can convert the above cloop based file into squashfs
Downloaded the deb package for squashfs-tools as knoppix does not carry it
dpkg -i squashfs-tools_4.2-5_i386.deb
mounted using cloop instructions on knoppix wiki  especially the 2nd part where in it is documented to use "if you boot from the LiveDVD"
Say if the mount is /mnt/cloop which holds your clooped image of  knoppixcloop
Ensure that you can see the entire filesystem of knoppix like /proc , /tmp , /etc inside /mnt/cloop.

Converted that to squashfs to down to 3.8gb by following the instructions
mksquashfs /mnt/cloop /knoppixsquashed

mount the squashfs file on /mnt/squashfs using the command
mount /knoppixsquashed /mnt/squashfs -t squashfs -o loop
mkdir in /tmp called fuse.In my case /tmp is in the memory so it gets wiped our everytime
unionfs-fuse -o cow /tmp/fuse/=RW:/mnt/squashfs/=RO /mnt/knoppix/

Executed the following commands as root

mount -o bind /proc /mnt/knoppix/proc
mount -o bind /dev /mnt/knoppix/dev
mount -o bind /dev/pts /mnt/knoppix/dev/pts
mount -o bind /sys /mnt/knoppix/sys
mount --bind /tmp /mnt/knoppix/tmp
cp /etc/resolv.conf /mnt/knoppix/etc/resolv.conf


chroot /mnt/knoppix/ /bin/bash
If all goes well your knoppix chroot environment should be up and running .You can try out a few simple commands like xclock etc.
in chroot environment need to run the following commands without which most kde apps dont work
dbus-launch
export $(dbus-launch)

you can also launch lxpanel in case you want to see what applications are installed.It might overlap with your existing panel if it is as the bottom but once you do a Ctrl-C your panel will be shown.

Post comments Knoppix Forums

References
http://basictheprogram.blogspot.com/2011/02/how-to-chroot-simple-and-fast-archive.html

TODO
Try compressing more for squashfs as default is very low compression
See if the step of extract_compressed_fs can be eliminated by loading the cloop directly and then making a squashfs

posted at: 01:09 | category: /linux | permanent link to this entry | Donate via Bitcoin
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There is very little information on formatting the clock which comes with XFCE and by default it is set to show 24-hour clock as opposed to the AM/PM which is probably more commonly used.
So I searched quite a bit to change this to be more of AM/PM format and found this link .However the problem is that once I would use any custom formatting on my next reboot it would still revert back to the original 24-hour clock.
In order to make your formatting changes permanent edit the file ~/.config/xfce4/panel/clock-14.rc and change the format there.

posted at: 19:14 | category: /linux | permanent link to this entry | Donate via Bitcoin
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I have jotted down couple of notes on debugging Juniper VPN client one of the most difficult software to install on any flavours of Linux.
My company uses RSA key fob with login to authenticate users on juniper network.My company also runs host checker to ensure our companys minimum standards are met.
In any case here are the rough steps for debugging, hope it helps someone as I spend a good amount of time trying various things to get my VPN working.

• On a 64-bit system ensure that you have both 32-bit & 64-bit java from Sun.As of this writing , based on my findings on internet it is not possible to run any other java with juniper VPN client other then from Oracle/Sun.On a 64-bit machine you have to have 32-bit java , otherwise it will not work.
• Verify in your firefox(on debian it is called iceweasel) that your java plugin is loading , by going to the location about:plugins in your location bar.Here 32-bit or 64-bit java plugin does not matter
  
• Login to your company's VPN portal , it will be something like https://www.<your company portal>.com
• You might be asked to "Allow to install software" that is Juniper client etc.Go ahead and click ok.
• Now navigate to your home directory and see a folder by the name .juniper_networks gets created.If this folder is not created nothing will work and most likely your java plugin is not working.It has to be fixed else it just won't work.
  
• Now navigate to the folder $HOME/.juniper_networks/network_connect , and you might be able to see a file named ncsvc.log .In my case I was never able to see this file , the reason was because Juniper client was trying to launch 64-bit java , and fails silently(no errors anywhere) because it has one file which is 32-bit and the file is libncui.so, here is the output of file command
  
• file libncui.so
  libncui.so: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, stripped
• Also in my case even though the 64-bit java client was dying silently according to the screen of Juniper which you see in your browser when you login , it was saying you have full access to your company network.However nothing happened.
• If you don't see the network connect GUI that means you are not connected to your VPN inspite of the VPN connectivity page showing that you are connected to VPN in green.You can verify that by checking your ipaddress and it will not be in your companies range.You can also run the command  ./ncdiag -a in the folder $HOME/.juniper_networks/network_connect and you will see it sayd network client not installed.If that happens then you are not on the VPN.
  
• Follow the good instructions @ this forum thread to modify your java to launch 32-bit if the invoking program is Juniper Client.This simple bash script does the trick.
• Now again navigate to your company's VPN portal.
• If everything goes well you will see a Network Connect UI window popup and it will tell you your IP address, how long you have been connected and so on.
  

Othe threads that helped me
http://www.rz.uni-karlsruhe.de/~iwr91/juniper/
http://pthreads.blogspot.com/2010/11/connecting-to-juniper-vpn-from-linux.html

posted at: 13:11 | category: /linux | permanent link to this entry | Donate via Bitcoin
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I'm a big fan of taking backups of entire hard drive or partitions , using dd.It provides a platform/OS/filesystem independent mechanism to take images , though there is a slight penalty that it even copies unused bytes.
Recently I had a need to convert my DD based image which had my ext3 filesytem so that I could convert it to an ext3 actual partition using partimage.Now the problem is that partimage works only on devices and cannot read a partition from a DD based image or for that matter any file based image/filesystems etc.
Loop device comes as saviour in this situation.
So what i did was loaded my dd based image as loop device using the command below, essentially fooling partimage that the filesystem in my file is an actual physical partition.
losetup /dev/loop0 /mnt/myDDimage.img
Now when you start partimage , you can see that /dev/loop0 is shown as a filesystem and you can do the conversion.

posted at: 03:12 | category: /linux | permanent link to this entry | Donate via Bitcoin
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After searching painstakingly on the internet I finally figured out how to use Microsoft Live Meeting on Linux.MS live meeting is something which our IT wants us to use :-(.
In any case to make it work with java 1.6 , pls follow the steps on this page.

posted at: 05:33 | category: /linux | permanent link to this entry | Donate via Bitcoin
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So I recently got  the CS50-USB Wireless Office Headset System  to use with my various softphones for  VOIP communications.
And obviousously I wanted to use it with my Linux machines.
My main goal was to use it with Ekiga for making VOIP calls with Gizmo5(will soon move away from gizmo5 because it was  acquired  last week by google and i prefer not to use another monopoly named google).
So while ekiga was running I connected the USB headset and ekiga was smart enough to detect that a new headset was connected and whether I wanted to use that as my default device.I selected yes.
Then I tried to make a call and got error messages from Ekiga that it could not open the device  "Plantronics CS50/CS60-USB Headset (PTLIB/ALSA)" and suggested that there might be a permission issue to open the device or I might have to plug/unplug again.
To rule out all those possibilities I used root to launch ekiga and also reconnected the headset but i continued to get the same error message from Ekiga.
So after playing with it for a few hours i finally figured out what the problem was.
So the issue is that Ekiga detects and uses the following parameters under  Edit->Preferences->Audio->Devices
Output Device  : Plantronics CS50/CS60-USB Headset (PTLIB/ALSA)
Input Device  : Plantronics CS50/CS60-USB Headset (PTLIB/ALSA)

But with those devices I could never make it work.
So I changed the above devices to the following and voila everything was working perfectly.

Output Device  : CS50/CS60-USB Headset (PTLIB/ALSA)
Input Device  : CS50/CS60-USB Headset (PTLIB/ALSA)

posted at: 16:38 | category: /linux | permanent link to this entry | Donate via Bitcoin
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If you are using sidux on a USB stick in persistent mode  and have ran out of disk space on sidux-rw file(file where all your changes are stored by sidux) and you want to increase the filesize without data loss then you can do the following.

Disclaimer : Please have backups of everything .I cannot  be held responsible for any data loss.Use this information at your own risk.
The sidux-rw file  is located on your usb drive or any other medium in the following folder <USB drive>/sidux/sidux-rw
The file itself is really a sparse file which contains an ext2 partition in it.

So essentially what we will do is resize the ext2 partition.Typically you would need to increase the size of the contactiner partition but in this case there is no parent parition because this is a sparse file , all we need to do is just resize the ext2 partition by using a few tools.
So you will need to boot into any Linux distro like sidux .But please ensure that the file sidux-rw is not mounted as the resize will fail and you might end  up loosing data .
Now we need to ensure the filesystem itself is healtthy.We need to check that without which resize2fs will not work.
Navigate to the folder which has the sidux-rw file and issue the following command as root
# e2fsck -f sidux-rw

You will need to fix all the recommendations by e2fsck.
After doing that you will be ready to resize your filesystem.
So now issue the following command as root to resize your sidux-rw file to say for example 512M
#resize2fs sidux-rw 512M

Please note that this instructions are for increasing the size only.I have not tried reducing the size of the file.Also note that the filesystem has to be ext2.

posted at: 16:18 | category: /linux | permanent link to this entry | Donate via Bitcoin
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Text to speech is very simple in Linux.You just need to install a package called espeak which will most likely be available with your favorite distro.
Once  you have espeak installed you can issue the following command

echo "hello" | espeak

If everything goes well you will hear Hello from the speakers.

You can read more about espeak @  http://espeak.sourceforge.net

posted at: 21:48 | category: /linux | permanent link to this entry | Donate via Bitcoin
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