HOW TO’s

Recover GRUB BOOT Loader after installing Windows

Follow the easy steps to recover the grub boot loader after reinstalling Windows OS. Boot the PC from Live LINUX CD and issue the following commands on the console and get the grub loader back.

sudo grub

find /boot/grub/stage1

root ( HD0,1)

change the values 0,1 according to you disk layout and the partition where Linux is installed.

setup (hd0)

quit

Reboot the machine and the grub loader is installed.

Setup LTSP – Remote Boot  PXE Enabled Thin Clients of PXE enabled PC/Laptops

We would first install the Required applications step by step and then configure them later.

• 1.Install the Regular Ubuntu Desktop Distro, I am using ubuntu 9.04 for this howto.

• 2.Once Installed, update the distro and install all the necessary updates.

• 3.Once Done Install NFS kernel Server via this Command : sudo apt-get install nfs-kernel-server

• 4.Install the DHCP SERVER on the same machine,make sure there is only one dhcp server running on the network else.it will cause a conflict.

• 5.Set a static ip to the machine via /etc/network/interfaces file – i am using 192.168.0.1 as SERVER ip for this HOWTO.

• 6.Now install the server module for LTSP running this command on terminal : – sudo apt-get install ltsp-server-standalone openssh-server ( this would install the LTSP Server and the openssh on the desktop.

• 7.Now Create your Thin Client environment on the server with this command: sudo ltsp-build-client

The First command installs the LTSP SERVER and the Second command installs the module that  will provide/create  the environment  to run the remote disk less machines. ( Please be patient, the client module takes time to install as it fetches about 150 MB of files from the repos. )

Once the client installation is done run these 2 commands to create the ssh keys

sudo ltsp-update-sshkeys

sudo ltsp-update-image

Be sure to do it in that order.

We are now done with the installation. now comes the configuration part.

• Open the /etc/default/tftpd-hpa and edit first line Run_Daemon to “Yes” in place of NO.Save and Exit.

• Now Open the /etc/ltsp/dhcpd.conf and change some values to the file as below.

• uncomment value next-server and put the server ip infromt of it ( next-server 192.168.0.1; )

• add these two values below that :

• allow booting;

• allow bootp;

• now go to the last line of the dhcpd.conf and it has a default value : filename (  ”/ltsp/i386/nbi.img”;  )   change that to (  filename “pxelinux.0″;  )

• Once done save and exit and restart the  dhcp server /etc/init.d/dhcp3-server restart

• Once done now u can just Boot the diskless workstations and it should aautomatically find the  dhcp server get an IP address and load the Remote OS. and Login.

Hope the above step by step helps you to get the LTSP up and running in less than an Hours’s time.

Setup NIS – Server & Client

Recently got a project to teach students to setup NIS SERVER,there seems to be lotsa of information about setting up NIS Client and Server but no where do u find the exact step by step way to do it.  Everyone Seems to be doing the Hit and Trial Methods,Below I  have just  mentioned the steps to setup an NIS SERVER and Client in less than 30 mins doing exactly as mentioned step by step. I had used debian Ubuntu for the SERVER setup and Centos 5.4 for the Client. Configurations Mentioned here work the same for any Distro.

NIS SERVER :

1. Install Portman Daemon.
2. Install NIS Server.
3. At the time of Installation Of NIS it will ask for the NISDOMAIN,enter ur hostname as the default NISDomain ( Eg.NISDOMAIN=HOMESERVER ).
4. Edit /etc/default/nis and set NISSERVER=TRUE & comment NISCLIENT=true.
5. Initialize the NIS files using the following command = /usr/lib/yp/ypinit -m.
6. Once this is complete you can run /etc/init.d/nis start with no errors.
7. Run  this command every time new user is added or removed to add to NIS db “make -C /var/yp”.
8. Export the /home Dir of the NIS Server via NFS so it can be mapped on the client machines and they can use the same to login and store their data.

NIS CLIENT

1. On the client, you need the yp-tools package, which depends on the ypbind package.
2. First you must setup the NIS Domain Name,edit the /etc/yp.conf file, and point it to the appropriate server and domain name. Remember that the domain name must be the same that you set for the server. For example, add the following line: domain HOMESERVER server 192.168.1.100
3. Start the NIS client service by entering:  /etc/init.d/ypbind start.
4. Map the Exported /home folder of the NIS SERVER to the local Client Machine into /home folder only.Rename the Existing /home folder on the client machines to /home.old,Remove all local Accounts from the client machines except root, so that only NIS Accounts work.
5. Once this process is done the accounts and personalized settings stored on the server are visible and available on any client machine and user can login by sitting on any of the clients retaining all his Files / Emails / Data / Bookmarks and Even Personalized UI settings…. .
6. Test the NIS SERVER by running ssh on the  local workstation and  login via telnet or ssh to the workstation using the user/password from the nis server password list..

Bingo that is all and u are ready to rock with NIS.

Remember the user/pass in  NIS are sent in clear text format over the network and they are not encrypted…..

We would first install the Required applications step by step and then configure them later.