mscom_linux_setup [Digitale Elektronik und Technische Informatik]

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===== Ubuntu Linux Installation for Network analysis =====

The network analysis is done with a collection of tools in a linux environment. 

  * iperf Performance Measurement
  * Wireshark Packet Tracing
  * [[http://www.linuxfoundation.org/collaborate/workgroups/networking/netem|netem]] Network emulation
  * tcp_probe Kernel module (see [[https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/tcp_probe.c|tcp_probe.c]])
  * tftp tiny file transfer protocol 
  * ethtool for network card settings

These tools are installed on top of [[http://releases.ubuntu.com/12.04/ubuntu-12.04.4-desktop-amd64.iso|ubuntu-12.04.4-desktop-amd64.iso]] installation from Ubuntu. To install the tools, run: 

<code>
sudo apt-get install git iperf wireshark gnuplot tftp ethtool tftpd-hpa
</code>

For the tftp daemon, change the setting of TFTP_OPTIONS in the file

<code>
/etc/default/tftpd-hpa
</code>

to <code> TFTP_OPTIONS="--secure --create" </code>. Then change the owner of the tftp directory

<code>
sudo chown tftp:tftp /var/lib/tftpboot
</code>

Starting and stopping of the tftp server is done with

<code>
sudo service tftpd-hpa start
sudo service tftpd-hpa stop
</code>

=== Live CD Creation ===

For the lab I have bootable usb sticks which contain the Ubuntu live system plus a persistent storage which already contains the additional installed packages and the home directory files. 

Here is the guide for creating a usb live boot stick: [[https://help.ubuntu.com/community/LiveCDCustomization]]

The steps to produce such a bootable usb stick are

  - Create a FAT partition of approx. 4 GB size with the Ubuntu disk utility on the usb stick
  - Start the graphical "Startup Disk Creator", select the iso image [[http://releases.ubuntu.com/12.04/ubuntu-12.04.4-desktop-amd64.iso|ubuntu-12.04.4-desktop-amd64.iso]] and choose "Documents and Settings will be stored in reserved extra space" with size of approx. 1GB. Select the USB Device you have in the usb slot. 
  - Create the USB Stick with "Make Startup Disk" 
  - Eject the stick and inject it again. This will mount the stick and you can look at the file contents. 
  - You need to change the file /boot/grub/grub.cfg due to a bug. Add the word "persistent" to the linux parameter of "Try Ubuntu". See below for the corrected part of grub.cfg.  
  - Now boot your computer with the stick. You should boot from a computer which is connected via ethernet such that you have internet connection. 
  - Install the packages you need and add the files you want to the home directory. I added the socket programming source files. These changes are persistently stored now. 
 
Her is the corrected extract from the grub.cfg file: 
<code>
...
menuentry "Try Ubuntu without installing" {
	set gfxpayload=keep
	linux	/casper/vmlinuz.efi  file=/cdrom/preseed/ubuntu.seed boot=casper persistent quiet splash --
	initrd	/casper/initrd.lz
}
...
</code>

=== USB stick copy ===

In order to avoid problems with the USB stick copy step, the size of the initial FAT32 partition should be smaller than the maximum size of the USB stick. I selected 4 GB for the FAT 32 which includes the 1GB persistent caspar-rw file. The stick size is 16GB. I had success with copying the first 4 GB (in fact 5GB) from the stick to a file with 

<code>
sudo dd if=/dev/sdb of=mscom.iso bs=1M count=5000
</code>

That produces an mscom.iso file with size 5,2 GB which is well above the 4 GB. Maybe count could have been smaller... Now you can copy that to a new USB stick with 

<code>
sudo dd if=mscom.iso of=/dev/sdb bs=1M
</code>

**IF YOUR USB STICK IS AT /dev/sdb AND NOT YOUR HARDDISK....**