[syslinux] PXElinux question - not in FAQ

[H. Peter Anvin]

Woody Suwalski wrote:
> Peter, we have met in Cyber space looong time ago, when I was requesting 
> 10:minor numbers for the Netwinder project....
> 
> Now I am trying to build a network boot for Xandros distribution.
> 
> I have it working, however I need to do 2 DHCP cycles - 1 happens in 
> PXE, and then it repeats in my network boot code (based on BusyBox). All 
> I need in the second stage is the NFS image address, passed by DHCP as
>    option root-path "dell:/XandrosInstallCD";
> 
> I could modify DHCP to use option vendor-encapsulated-options instead. 
> Is this one "eaten" by PXE firmware? What for is it in the first place?
> 
> Would be nice if PXE linux could pass on the kernel command line other 
> vars similar to IPAPPEND info, but from your code  it looks that 
> pxelinux is not parsing other DHCP options...

It doesn't, and it might not even get them without asking the DHCP 
server specifically *in the request*.

Once initramfs is supported in the kernel there will probably be a way 
to get the PXE packets in binary form passed to the kernel.  However, 
quite frankly, I think you're actually better off doing exactly what 
you're doing now -- ask DHCP twice.

	-hpa