[syslinux] UEFI PXE / split config / TFTP attempted to DHCP server, not TFTP server

[Gene Cumm]

On Wed, Sep 24, 2014 at 11:22 PM, Spike White <spikewhitetx at gmail.com> wrote:
>>Date: Sun, 21 Sep 2014 22:19:12 -0400
>>From: Gene Cumm <gene.cumm at gmail.com>
>>To: Spike White <spikewhitetx at gmail.com>
>>Cc: For discussion of Syslinux and tftp-hpa <syslinux at zytor.com>
>>Subject: Re: [syslinux] UEFI PXE / split config / TFTP attempted to
>>        DHCP server, not TFTP server
>>Message-ID:
>>        <CAD0RxembHwQ5VMbnNgmgbfUgzgdhnnXNCgzFWb5+BHLNTqez2g at mail.gmail.com
>>
>>Content-Type: text/plain; charset=UTF-8
>>
>>
>>At least it's another datapoint for Dell.
>>
>> ...
>>
>>Check the packets.
>
> Gene,
>
> It was a Dell R710 UEFI PXE firmware bug!!
>
> I tested today w/ a Dell R620.  Behaved exactly as expected.
>
>   w/ DHCP option 43 == 'PXEClient', does the:
>      D-O-R-A to DHCP server, then
>      (proxyDHCP) R - (proxyDHCP) A - TFTP to the TFTP server
>
>   w/o option 43 set, does:
>      D-O-R-A to DHCP server, then
>      TFTP to the TFTP server
>
> I spent 3-4 days trying to figure out what I was doing wrong.  Nothing!
> It was a firmware bug.
>
> Thanks for explaining to me that old-school DHCP/TFTP split.  Hopefully,
> I'll
> never use it.  (I see no value w/ modern PXE-capable DHCP servers -- it
> just overly-complicates things).
>
> But at least I'll understand it when a boot client starts doing it.

Your initial config was the old-school split.  I specified how PXE
extended the behavior to allow to a separate boot config offer/ack
from the IP config offer/ack instead of needing to pick everything
from one offer.
-- 
-Gene