[ipxe-devel] Testing for sanboot feature on DHCP server (solution)

Johannes Thoma johannes at johannesthoma.com
Thu Jun 13 18:41:18 UTC 2019


Am 13.06.19 um 18:46 schrieb Geert Stappers:
> The improvement can be made by reporting _how_ the problem was solved.
> So take some time to document what the solution was.
Sorry, I was writing this eMail in a hurry and thought one would read
the whole thread anyway: Here's how it solved my problem (which was
chainloading a custom-built iPXE image which supports sanboot via
http with VirtualBox (on a MacOS X host):

We are using isc-dhcp-server (sudo apt-get install isc-dhcp-server
on Ubuntu) as the DHCP server software on Ubuntu.

1.) Add the DHCP options from


near the beginning of /etc/dhcp/dhcpd.conf

2.) Add following lines (you can skip the comments) further down
in /etc/dhcp/dhcpd.conf (replace the URLs with location of sanboot
enabled iPXE image and script that serves the (Windows) boot device):

# this distiguishes the default VirtualBox iPXE image from our
# custom built one:
if exists ipxe.iscsi {
         filename "";
# This causes iPXE to sanboot from this http site
         option root-path "";
} else {
# This causes our custom built iPXE image to be chainloaded:
         filename "";

> Use it as a way to express you understand there
> is both "give and take".
I perfectly understand. That's one of the reason I wrote the http
sanboot large image support for 32-bit iPXE images earler (see [1])
It hasn't been touched for a while, but I am definately ready to
improve the code if required. It is probably not the most wanted
feature, but it helped me to boot Windows via sanboot http also
on 32-bit builds.

Best wishes,

- Johannes Thoma

[1] https://www.mail-archive.com/ipxe-devel@lists.ipxe.org/msg06391.html

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