Re: Kernel DHCP unpredictable/fails (PXE boot), userspace DHCP works just fine

From: Daniel Braniss <danny_at_cs.huji.ac.il>
Date: Sat, 18 Mar 2023 09:55:49 UTC

> On 17 Mar 2023, at 22:16, Attila Nagy <nagy.attila@gmail.com> wrote:
> 
> Matthias Pfaller <leo@marco.de <mailto:leo@marco.de>> ezt írta (időpont: 2023. márc. 17., P, 7:24):
>> 
>> Do you have STP/RSTP enabled on the switch ports? When the link goes down when 
>> switching from firmware mode to kernel mode, the port will go back to blocking. When 
>> the dhcp requests don't make it to the dhcp server because of this and the link goes 
>> down and up again while retrying (don't know if this happens) you will get the same 
>> problem on the next try. As a simple test you could put a dumb unmanaged switch 
>> between your core network and the server.
> Thanks for the idea, but I don't think this might be the case.
> I can see the UDP datagrams coming into the kernel (replies to DHCP messages).

take look at src/stand/libsa/bootp.c, there is a compile option that allows many
more options to be transferred via dhcp … 

BTW, where possible I’m moving  to uefi, since pxeboot is failing with file to large …

another issue i have with pxeboot, 
older versions work - better - , some are terribly slow,
and some just hang.

danny