[syslinux] Question about pxelinux and gpxelinux

[H. Peter Anvin]

Sean Lv wrote:
> 	1, after I read the document
> (http://edgyu.excess.org/ols/2008/H%20Peter%20Anvin%20-%20x86%20network%20bo
> oting%3a%20integrating%20gPXE%20and%20PXELINUX.pdf), I knew there are two
> major module in standard gPXE, PXE BC and UNDI. And I can understand why I
> need to produce different boot file for different NIC from
> http://rom-o-matic.net/, because the output file contain different UNDI.
> But I am really confused that why only one gpxelinux.0 (in syslinux 3.72
> package) could support all my NIC (at least 5) in my environment?  I guess
> the gpxelinux.0 use its own PXE BC and call vendor-UNDI from physical PXE
> ROM, as a result, gpxelinux.0 could support all my NIC(actually, it is
> supposed to support all NIC which have PXE ROM)  Am I right?

Yes.

> 	2, From rfc5071, pxelinux should request non-standard DHCP option
> from DHCP server, option 208-211. In my environment, I am using a Microsoft
> DHCP (Windows 2008). And I tried to set option 67 (boot file name) to
> publish pxelinux.0 & gpxelinux.0. I used wildpacket(just like Wireshark) to
> capture the packets btw PXE client and DHCP server. I could not see PXE
> client request option 208/209/210/211, although I am sure I configured these
> syslinux-DHCP option on my DHCP Server.  Why? I searched the google and
> official web site, all examples are using a linux-DHCP Server. I am not
> familiar with linux, and I am not sure if my issue is related to my
> Micrsoft-DHCP Server.  
> 
> 	It's appreciated if you can help me out. Thanks in advanced.
> 

PXELINUX doesn't request anything from the DHCP server, *because
PXELINUX isn't running yet*.  DHCP is done by PXE, so you have to
configure your DHCP server to send these options without having had them
requested.  This is also mentioned in RFC 5071 (fifth paragraph of
section 1.)

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.