dhcp
PXE Boot – Thin Client LTSP Config
Dec 19th
The main component of LTSP (Linux Terminal Server Project) is the dhcp configuration. To start install the required packages:
sudo apt-get install ltsp-utils ltsp-server ltsp-server-standalone
Then open /etc/ltsp/dhcpd.conf, which is a template of your possible dhcp3 configuration. To makes things simple just use everything in this file as the configuration for dhcp, otherwise if you are comfortable configuring the option feel free; they can be configured many ways! The main dhcpd configuration file is located in /etc/dhcp3/dhcpd.conf. Do not forget to turn off the dhcp server in your router!!!!!! This will cause conflict. Also include next-server “serverip” in the dhcpd configuration. This is required to point secondary ip traffic, during PXE boot, to the ltsp server. Now just build your client environment and your ready to PXE boot:
ltsp-build-client
There are additional lstp configurations that can be done with ltspadmin. You can use ltspadmin to set a gdm login screen for your thin clients; I prefer to not use the gdm. You can use ltspadmin with:
sudo ltspadmin
The rest is terminal graphics. You can monitor the status of your various ltsp components, and set additional sometimes necessary configurations.
Now you might get stuck at various places. One place is the tftp during the pxe boot process. This may be the setting the export correctly in /etc/exports. Add if its not there:
/opt/ltsp *(ro,no_root_squash,async,no_subtree_check)
Then maybe you need to configure the next server option. DHCP is configure in /etc/ltsp/, and not directly in the dhcp /etc directory. Add or uncomment accordingly:
next-server ip.address.of.server;
The whole kit and kaboodle is described in greater detail on the debian wiki.
Network Interfaces Configuration File
Dec 8th
In your /etc ditectory is the network folder. In the network folder is the interfaces file that contains all the data used to configure your network. The default configuration is dhcp. You can configure this file manually, to a limited degree, via the administration>>network panel. For most applications dhcp will be fine, and therefore you can leave your default configuration. If you want to setup a static ip, for your primary ethernet card, use the administration>>network configuration menu. You can set any static local ip outside the range of the dhcp configuration on your router. You can disable the dhcp of your router to set static addresses for the lower safe range. The default dhcp range is typically 192.168.0.2 to 1982.168.0.50. After disabling dhcp you can disable network manager in the preferences>>sessions configuration menu. If you are using a bridge and tap I highly recommend direct configuration of your interfaces via the /etc/network/interfaces file. Please refer to my previous post for more information about bridge and tap configuration.
VirtualBox Host Networking Set Host Static Local IP
Dec 5th
If you are running a guest operating system, and are utilizing host networking via a bridge and tap, you should set the host IP address statically. On my other machine I was able to utilize DHCP for the host IP, but on this machine when the guest IP address is set the host has trouble DHCP’ing and new IP address. Overall setting IP address statically is important to keep track of utilized and available IP addresses. DHCP is really only useful in practice when anonymous machines are connecting and the MAC addresses are new to the router.
Virtual Server Can Fool Hackers – Backup/Restore is Easy
Nov 12th
When a virtual server is utilizing the host systems network, and receives an independent local IP via DHCP from your router it appears to be an actual computer form the outside world. If a backup of the VDI is kept regularly it can simply replace a damaged, or hacked system in the time it takes to copy a file. Virtual servers exist as a single VDI file, therefore for blogs that utilize database backends simply copy your backup server VDI image, boot, then use your phpmyadmin to update your mysql databases from your backups; obviously this entails keeping mysql database backups. For more information about mysql backups utilizing automated cron scripts see: http://www.bgevolution.com/blog/index.php/cron-server-backup-scripts/
VirtualBox Host Networking (Grab an IP Via DHCP)
Nov 3rd

- Image via Wikipedia
I use the following commands in a boot script. I posted about this a while back, and ran into some trouble re-doing the procedure, so I though I would post about what I learned the second time around.
Replace “primaryusername” with the user that you login with. Replace eth0 with your primary adapter name. Replace 192.168.0.11 with an unused IP address that is provided by your DHCP server. Replace 192.168.0.2 with another IP address that is provided by your DHCP server. Make sure both IP addresses are not currently in use!!!!!!
sudo tunctl -t tap0 -u primaryusername
sudo chmod 666 /dev/net/tun
sudo /usr/sbin/brctl addbr br0
sudo /sbin/ifconfig eth0 0.0.0.0 promisc
sudo /usr/sbin/brctl addif br0 eth0
sudo /sbin/dhclient br0
sudo /usr/sbin/brctl addif br0 tap0
sudo ifconfig tap0 192.168.0.11 up
sudo bash -c ‘echo 1 > /proc/sys/net/ipv4/conf/tap0/proxy_arp’
sudo route add -host 192.168.0.2 dev tap0
sudo arp -Ds 192.168.0.2 eth0 pub
After these commands are run, configure your VirtualBox to use Host Networking, with the device name being tap0.
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