[K12OSN] DHCP and different LTSP distros

[William Fragakis]

If the PXE ver is older than 0.99 you have to edit a couple of files on
the server to break the tftp down slow and small enough for it to work.

see here for the details:
http://morrisbrandon.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=34&page=3
(note: this was the instructions for k12ltsp 4.4.2. I'll need to update
this over the summer as we are now on ver. 6.0)

quickly:

Tweaks for servers serving older PCs:
If the PC, while PXE booting fails to get further than grabbing an IP
address or begin tftp, you likely an older PXE firmware (0.99) that
requires certain tweaks. Newer clients do not require these steps but it
doesn't hurt to do them to facilitate easy swapping of clients later.
We've only found this to be an issue with PII 350 and 400 Compaq
DeskPros.
Open the computer -> filesystem -> /etc 

open file /etc/sysctl.conf (it should open with Gedit or Kedit) append
the file with the following (Include the # sign! It denotes a comment
which is for human eyes and for the server to ignore. Well commented
files make things easy for those who follow you.)

# Disable MTU discovery for older PXE NICs (0.99)
net.ipv4.ip_no_pmtu_disc = 1

save the file and close

next, open file /etc/xinetd.d/tftp

change this line:
server.args = -s /tftpboot

to:
server.args = -r blksize -s /tftpboot

save the file and close (essentially, you are adding the -r blksize
parameter). This change unlike any others will not be effective until
you reboot the server. This is the only change that requires a reboot
since it is kernel level. All other changes are package or service level
and only require restarting that application or service. 





On Thu, 2007-06-28 at 08:53 -0400, k12osn-request at redhat.com wrote:
> 
> Message: 3
> Date: Wed, 27 Jun 2007 21:34:53 +0300
> From: Mella <mellax at pm.ee>
> Subject: Re: [K12OSN] DHCP and different LTSP distros
> To: k12osn at redhat.com
> Message-ID: <4682ADCD.8080504 at pm.ee>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Now I found a problemmaker! :)
> 
> It is Compaq Deskpro SFF client with built-in Intel PXE? card driven 
> only from Compaq BIOS. It just cannot boot from another server than 
> DHCP! And Intel boot rom is not separately flashable.
> It claims  "Old PXE API detected, using PXENV+ structure" when
> booting.
> 
> If i tried this with IBM T20 (3com PXE card onboard), all works OK 
> without TFTP service in DHCP server.
> 
> Unfortunately I have 50 Compaq's here :(
>