[Dnsmasq-discuss] UEFI PXE Boot Issue: dhcp-option 60

Geert Stappers stappers at stappers.nl
Mon Dec 7 13:49:03 GMT 2020


On Mon, Dec 07, 2020 at 01:11:18PM +0000, Swanand Vaidya wrote:
> Hi,
> 
> I am trying to PXE boot a UEFI enabled Dell machine with dnsmasq acting
> as both the DHCP and TFTP server.
> The client and server perform the DHCP steps: DHCP Discover, DHCP Offer,
> DHCP Request and DHCP Ack as expected.
> 
> But, thereafter, the client simply aborts the protocol (it does not
> do TFTP to download the NBP file syslinux.efi and others) and I can
> see error:
> "PXE-E21: Remote boot canceled" on the client console.
> 
> The same dnsmasq configuration works for booting a BIOS based machine.
> 
> I found that dnsmasq is sending dhcp-option 60 with value as "PXEClient"
> which is causing this issue.
> 
> I could not find any way to disable this from being sent to the client.
> 
> Finally, I modified the source code in rfc2131.c by adding "return"
> statement at the top of the function pxe_misc(). The dnsmasq binary
> so built now works fine for booting the UEFI machine.
> 
> I would like to know:
> 
>   1.  If this is a known issue? I tried latest 2.82 version of dnsmasq
>       as well as building from the latest source snapshot from HEAD.

Did that include http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=4ded96209e8346711f9d0b9e13a835d42835853d ?
Yes, that is a very very fresh commit.  And it is 'PXEClient' related ...


>   2.  Is there any way to disable dhcp-option 60 from being sent over
>       to the client by setting some configuration param in
>       dnsmasq.conf? We can force certain option to be sent using
>       dhcp-option-force directive, but there is nothing for the opposite
>       direction to "force disable" a specific DHCP option. (Setting
>       dhcp-option = <option_number> without a value only works for
>       certain dhcp options).
> 



> Thanks,

You are welcome.



> -swanand

Regards
Geert Stappers

P.S.
I usually don't do "Reply to All", but I do take insults.
-- 
Silence is hard to parse



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