[Dnsmasq-discuss] pxe-service entries in dnsmasq conf seem to fail non-proxy EFI boot

Shrenik Bhura shrenik.bhura at gmail.com
Mon Sep 27 15:26:43 UTC 2021


Hi Petr,

The proposed config (also given below) doesn't work in non-proxy mode. I
tested it with a RPi 4B and Intel NUC in non-proxy mode.




*pxe-service=tag:!iPXE,X86PC,ltsp/undionly.kpxe
pxe-service=tag:!iPXE,X86-64_EFI,ltsp/snponly.efi
pxe-service=tag:iPXE,X86PC,ltsp/ltsp.ipxe
pxe-service=tag:iPXE,X86-64_EFI,ltsp/ltsp.ipxe*
*# fallback for BIOS-only clients without PXE support*
* dhcp-boot=tag:!iPXE,ltsp/undionly.kpxe*

On NUC*, *we get this after fetching IP -
PXE-E77: Bad or missing discovery server list

On RPi it endlessly loops at -
[43:9]: 'ltsp/undionly.kpxe   '

However, your proposed config works fine in proxy mode with just one
addition for RPi -
pxe-service=tag:rpi,X86PC,unused

But this is already known and that's why tag:proxy was introduced to bring
into play pxe-service only when using in proxy mode.

I have this more precise finding and at the risk of repeating myself -
With the below configuration in non-proxy mode, RPi and Intel NUC boot BIOS
boot fine but Intel NUC in UEFI mode doesn't.
pxe-service=tag:rpi,X86PC,"Raspberry Pi Boot    ",unused
dhcp-boot=tag:!iPXE,tag:X86PC,ltsp/undionly.kpxe
dhcp-boot=tag:!iPXE,tag:X86-64_EFI,ltsp/snponly.efi
dhcp-boot=tag:iPXE,ltsp/ltsp.ipxe

However, if I just comment out the pxe-service line, all works fine for
Intel NUC in BIOS and UEFI mode but now RPi won't boot. This is exactly
what I had started this thread with. Hence I shared the pcap dump and logs
in the previous post.

Best regards,
Shrenik


On Mon, 27 Sept 2021 at 19:40, Petr Menšík <pemensik at redhat.com> wrote:

> I think this should have been:
>
> pxe-service=tag:!iPXE,X86PC,ltsp/undionly.kpxe
> pxe-service=tag:!iPXE,X86-64_EFI,ltsp/snponly.efi
> pxe-service=tag:iPXE,X86PC,ltsp/ltsp.ipxe
> pxe-service=tag:iPXE,X86-64_EFI,ltsp/ltsp.ipxe
> # fallback for BIOS-only clients without PXE support
> dhcp-boot=tag:!iPXE,ltsp/undionly.kpxe
>
> Does LTSP still support booting outside PXE standard? Does it need to be
> supported? I think only non-PXE capable clients should fall back to to
> dhcp-boot parameters. All others should have some pxe-service entry.
> Current code does not allow different configuration I think. Even without
> iPXE, PXEClient will get boot parameter ONLY from pxe-service. It would get
> dhcp-boot parameter only if there is no pxe-service used at all.
>
> It seems pxe-service is IPv4 only at the moment. Any device trying to boot
> over IPv6 would probably boot only using:
>
> dhcp-option=option6:bootfile-url,ltsp/ltsp.ipxe
>
> Which is a bit sad. I guess only input parameters and output options are
> somehow different. But it should offer similar paths also on IPv6. Maybe
> time would be found sometime to implement also IPv6 support.
>
> Cheers,
> Petr
> On 9/25/21 13:14, Shrenik Bhura wrote:
>
> Hi Geert,
>
> Your advice doesn't seem to work. Gives an error on the very first line
> that has been changed.
> tag:!iPXE,X86PC,ltsp/undionly.kpxe
>
> Thanks,
> Shrenik
>
> On Fri, 19 Mar, 2021, 15:54 Geert Stappers via Dnsmasq-discuss, <
> dnsmasq-discuss at lists.thekelleys.org.uk> wrote:
>
>> On Fri, Mar 19, 2021 at 11:05:05AM +0200, Alkis Georgopoulos wrote:
>> > Hi all,
>>
>> ;-)
>>
>>
>> > I'm one of the LTSP developers; I asked Shrenik to contact the dnsmasq
>> > mailing list because I feel this might be a dnsmasq issue.
>> >
>> > Specifically, success or failure depends on whether these five lines are
>> > commented out or not:
>> >
>> >
>> #pxe-service=tag:proxy,tag:!iPXE,X86PC,"undionly.kpxe",ltsp/undionly.kpxe
>> >
>> #pxe-service=tag:proxy,tag:!iPXE,X86-64_EFI,"snponly.efi",ltsp/snponly.efi
>> > #pxe-service=tag:proxy,tag:iPXE,X86PC,"ltsp.ipxe",ltsp/ltsp.ipxe
>> > #pxe-service=tag:proxy,tag:iPXE,X86-64_EFI,"ltsp.ipxe",ltsp/ltsp.ipxe
>> > #pxe-service=tag:rpi,X86PC,"Raspberry Pi Boot   ",unused
>> >
>> > You may find the full configuration files and logs at:
>> > https://github.com/ltsp/ltsp/pull/417
>> >
>> > The reason I feel it might be a dnsmasq issue, is that these tags are
>> NOT
>> > matched in Shrenik's use case. He's not using proxy mode and he's not
>> > booting a Raspberry Pi.
>> >
>> > So, "pxe-service" lines that are NOT matched, cause the problem,
>> > yet if they're commented out, the problem is gone...
>> >
>> > Would that be an issue with dnsmasq, or with the UEFI PXE stack?
>>
>> I go for something inbetween:
>>   UEFI PXE stack insisting on something that dnsmasq **configuration**
>>   doesn't yet provide. Or server side **configuration** is something
>>   that the client can't handle.
>>
>>
>> Advice:
>>   Leave out `pxe-service`, skip "PXE". Yes, do  iPXE    ;-)      [1]
>>
>> Transform
>> |
>> #pxe-service=tag:proxy,tag:!iPXE,X86PC,"undionly.kpxe",ltsp/undionly.kpxe
>> |
>> #pxe-service=tag:proxy,tag:!iPXE,X86-64_EFI,"snponly.efi",ltsp/snponly.efi
>> | #pxe-service=tag:proxy,tag:iPXE,X86PC,"ltsp.ipxe",ltsp/ltsp.ipxe
>> | #pxe-service=tag:proxy,tag:iPXE,X86-64_EFI,"ltsp.ipxe",ltsp/ltsp.ipxe
>> | #pxe-service=tag:rpi,X86PC,"Raspberry Pi Boot   ",unused
>> into something like[2]:
>> | tag:!iPXE,X86PC,ltsp/undionly.kpxe
>> | tag:!iPXE,X86-64_EFI,ltsp/snponly.efi
>> | tag:iPXE,X86PC,ltsp/ltsp.ipxe
>> | tag:iPXE,X86-64_EFI,ltsp/ltsp.ipxe
>> | tag:rpi,X86PC,unused
>>
>>
>> Request:
>>   Report back
>>
>>
>>
>> Groeten
>> Geert Stappers
>> Voetnoten:
>>  [1] iPXE  stands for  "It doesn't do PXE"
>>  [2] actual syntax not verified
>> --
>> Silence is hard to parse
>>
>> _______________________________________________
>> Dnsmasq-discuss mailing list
>> Dnsmasq-discuss at lists.thekelleys.org.uk
>> https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
>>
>
> _______________________________________________
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>
> --
> Petr Menšík
> Software Engineer
> Red Hat, http://www.redhat.com/
> email: pemensik at redhat.com
> PGP: DFCF908DB7C87E8E529925BC4931CA5B6C9FC5CB
>
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