[Dnsmasq-discuss] specifying dhcp options in proxy mode

Andriy Gapon avg at FreeBSD.org
Thu May 25 15:30:21 BST 2017

On 25/05/2017 14:30, Simon Kelley wrote:
> How does this handle the case that the PXE client has received _two_
> packets, one from the DHCP server with an IP address, and one from a PXE
> proxy server with netbbot information. Does GET_CACHED_INFO return one,
> or both, or the combined information from both?

Here is my understanding of how x86 FreeBSD network boot works on a high level.

First, the initial PXE client must be instructed to load and run FreeBSD
pxeboot.  pxeboot is a special loader, an intermediate stage that loads the
actual FreeBSD kernel.  pxeboot is itself a DHCP and PXE client.  In a typical
setup pxeboot uses NFS for access to its configuration files, the kernel and
kernel modules.  In that case pxeboot does want to get a root-path in an offer,
that's where it gets an NFS share path.  When pxeboot is ready to run the
kernel, pxeboot passes the DHCP lease information and the NFS path information
to the kernel, so that the kernel can properly configure its network interface
and mount the root filesystem over NFS.

Andriy Gapon

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