PXE booting Backtrack 4

[funkymunkey]

Hi,

I am going to assume that you have a working dhcp and tftp server, that is already pxe booting something, if not there are many guides on the net to explain how to do these things. I used Debian Lenny with tftpd-hpa, so I will be focusing on these but it should be easy enough to adapt to any other distribution.

You will only need the bt4-final.iso file, mount it and copy the whole contents into a directory called bt4 in your PXE root.

mount -t iso9660 -o loop bt4-final.iso /mnt
mkdir -p [PXEROOT]/bt4
cp -r /mnt/* [PXEROOT]/bt4/

Look through [PXEROOT]/bt4/boot/grub/menu.lst and decide which one you want to boot, you can boot all of them you will just need to create multiple entries in the next step. I chose the following:

title                Start BackTrack FrameBuffer (1024x768)
kernel                /boot/vmlinuz BOOT=casper boot=casper nopersistent rw quiet vga=0x317
initrd                /boot/initrd.gz

I am asuming that you have a working PXE boot server already so you should have the file [PXEROOT]/pxelinux.cfg/default, in which case just add the following lines:

LABEL bt4
        KERNEL bt4/boot/vmlinuz
        APPEND initrd=bt4/boot/initrd.gz BOOT=casper boot=casper nopersistent rw quiet vga=0x317 netboot=nfs nfsroot=[SERVERIP]:[PXEROOT]/bt4

Here is an example full [PXEROOT]/pxelinux.cfg/default file that only boots bt4:

TIMEOUT 100
DEFAULT bt4
PROMPT 1
DISPLAY /isolinux.msg
LABEL bt4
        KERNEL bt4/boot/vmlinuz
        APPEND initrd=bt4/boot/initrd.gz BOOT=casper boot=casper nopersistent rw quiet vga=0x317 netboot=nfs nfsroot=[SERVERIP]:[PXEROOT]/bt4

The main thing to note here is we are only appending 'netboot=nfs nfsroot=[SERVERIP]:[PXEROOT]/bt4' to the original line in the grub configuration. Create the file [PXEROOT]/isolinux.msg and put something like 'type bt4 to boot Backtrack 4 Final' in it.

Now on Debian type the following command to install nfs, if you are using a different distribution google will be able to tell you how to install nfs:

apt-get install nfs-common nfs-kernel-server portmap

Edit /etc/exports and add the line:

[PXEROOT]/bt4   [LOCALSUBNET](sync,no_root_squash,ro,no_subtree_check)

You can restrict it to a certain IP but I used the whole subnet for convenience. Lastly type 'exportfs -a' and you should be ready to go! Just boot up a pc, boot from the network card, type bt4 at the prompt and alas bt4 over the network!

Happy Hacking!

[bong0]

Thanks, this works for me! But there is one little thing to note:
in /etc/exports you might hat to add the parameter "insecure", which just makes nfsd listen on a non-common port, then the line should look like this:

[PXEROOT]/bt4 192.168.0.0/24(sync,insecure,no_root_squash,ro,no_subtree_check)

after that, if you haven't already:

exportfs -a
/etc/init.d/portmap restart

[EDIT]
There seems to be an issue with the backtrack kernel, squashfs v4.0.0 or nfs on Backtrack 4 final.
I tried to boot BT4f over PXE with the same options as above, exept "persistent" instead of "nopersistent". The kernel keeps reporting "end_request: I/O error, dev fd0, sector 0" after squashfs comes up, which seems to be well known since squashfs v3.x. My box has no floppy drive. If someone has a solution for this, please post it here!

[@ToMiK]

Hi,
First of all thanks for the tutorial. However, I am having an issue exporting the BT4 directory.
So far, have a DHCP and TFTP running on BT4.
Have edited the /etc/exports file, and saved the configuration.
When executing

exportfs -a

I receive the following error message

exportfs: Warning: /tftpboot/bt4 does not support NFS export

Any help would be greatly appreciated!
Thanks

[haggismn]

Is there any way to get persistent changes working by using the nfs server as the storage location? I've tried using changes={nfs}:/{dir}, but to no avail. Any ideas? It boots up off the server fine apart from that.