[syslinux] Chain-loading from WDS to PXELinux on a different tftp server

[Geert Stappers]

On Fri, Dec 26, 2014 at 03:32:21PM -0600, Spike White wrote:
> > Date: Thu, 25 Dec 2014 07:07:52 +0000
> > From: Luke Ledgerd <luke.ledgerd op niteco.se>
> >
> > Hey guys,
> >
> > We are going with WDS to fire up first to get the benefits of
> > targeted MS deployments. If you have the "handle unknown computers"
> > off on your MS Distribution point, then you can still use regular
> > WDS which runs next as a PXE filter (DLL linked into WDS) to fire
> > off anything you want to including PXELinux.
> >
> > The stuff I was talking about before with PXELinux not working in
> > EFI-64 was related to the EFI Network Boot Rom trying to connect to
> > the DHCP server on Port 4011 (PXE server). I could have kept hacking
> > around with DHCP options, or forced DHCPD to listen on that port, or
> > set up a proper PXEServer that complies with 3.X of the PXE spec, but
> > it wasn't required for what we wanted in this environment so I moved
> > on, and let WDS workaround the problem with EFI + PXELinux I had.
> >
> > Question.
> > 1) Can you kick off PXELinux without a Unix DHCP Server (WDS),
> > and make it jump to a different tftp server from WDS?

PXELinux is agnostic about what provided the information
to get pxelinux.cfg


> > That's what I'm
> > going for. I want the default PATH to include the IP address of a
> > different TFTP server in PXE Linux.
> >
> > The new implementation will have to have a separate folder for EFI64,
> > EFI32, PXE 2.1 because that's what I think WDS demands - or at least
> > for whatever chainloads the PXELinux off another TFTP server.
> >
> > 2) As a fallback, PXEChain as I understand requires another DHCP
> > server
> >
> > http://www.vcritical.com/2011/06/peaceful-coexistence-wds-and-linux-pxe-servers/
> > http://www.syslinux.org/wiki/index.php/Common_Problems#pxechain.com-2
> >
> > These docs look good by they don't explain how it all plays together
> > with PXELinux dual booting with EFI/Non EFI shared configuration.
> >
> > Does PXEChain do everything I want? Can it even a pass configuration
> > file for PXELinux to start with.pxechain
> >
> > This looks very interesting - This Russian knows what he is doing....
> > http://sysmagazine.com/posts/175669/

Previous in this thread there was `pxechn.c32` hinted,
see http://www.syslinux.org/wiki/index.php/Pxechn.c32 for information about it.


> > I'll let you know how I go today with it. We are going for the perfect
> > setup where SCCM does it's thing if it needs to - else throws back
> > to WDS -> PXELinux for a computer not targeted for any SCCM PXE
> > Deployment task sequences, so it's going to be a bit different from
> > the above article.

I looking forward for the webpage that documents such setup.


> > Why a different TFTP server? We have a NAS that is already setup and
> > tested and it does a good job of mounting lots of loopback ISO's and
> > sharing them on TFTP, even if it doesn't support MTFTP and all that.


IMHO: Having serveral TFTP servers is fine.
IOW: There is no reason to have only one TFTP server.

> >
> > Cheers,
> > Luke
> 
> Luke, I have considerable experience with this.  We use WDS at work for
> PXE (MS-centric shop).  I use pxelinux at home.
> 
> I've got WDS working in our test lab w/ UEFI.  As you state, it strongly
> wishes to do proxyDHCP (port 4011).  More on this in a bit.
> 
> It's quite common to segregate the DHCP server from the TFTP server.
> Commonly, it's because DHCP services is maintained why one team
> and PXE boot by another.
> 
> What you're desiring is somewhat obscure -- you're wanting your WDS server
> to provide the DHCP service, while you have another server provide TFTP.

What I understand from the original post is
reaching a limit/restriction of a Microsoft product.


> Normally, it'd be the other way around; some other server would be providing
> DHCP and WDS would be providing TFTP/PXE.  I'd argue for your setup what
> you really want is straight MS DHCP service (to provide DHCP).  and point it
> to your NAS (for TFTP).
> 
> Except that wouldn't work for your known servers.

I expect that a mixture "DHCP servers" is needed
to get beyond the limit / restriction of MSFT  WDS
to serve the mixture "(DHCP) clients".


> About proxyDHCP.  I'm loading wdsmfg.efi as the network boot program (NBP).
> So some of my tested configurations do the std D-O-R-A to the DHCP server
> and
> then immediately do a TFTP read request from my TFTP server.  Loading the
> boot\x64\wdsmgfw.efi.
> 
> However, then it does RA - RA - RA to the WDS server (proxyDHCP port 4011).
> I'm convinced it's the wdsmgfw.efi that's doing this.
> 
> Here's the best config I found:
>    TFTP Server Name (option 66) -- set to WDS server's IP address
>    Domain Name (option 15) -- set to DNS domain
>    File Name    set to boot\x64\wdsmgfw.efi
>    Next Server  set to WDS server's IP address
> 
> Also, you might try this config:
>    Boot File Name (option 67) -- set to boot\x64\wdsmgfw.efi
>    TFTP Server Name (option 66) -- set to WDS server's IP address
>    Domain Name (option 15) -- set to DNS domain
>    File Name    set to boot\x64\wdsmgfw.efi
>    Next Server  set to WDS server's IP address
> 
> That second config doesn't work for me, because of a bug in the EFI boot
> code of my Intel and Broadcom NICs.  It interprets option 67 as
> boot\x64\wdsmgfw.efi\377 .  (Don't want to re-hash this; been discussed
> thoroughly in this mailing list before).

Mmm, I think I missed that ...


> Spike White


Groeten
Geert Stappers
-- 
Leven en laten leven