[ipxe-devel] iPXE DHCP failure

Michael Brown mbrown at fensystems.co.uk
Wed May 18 09:57:50 BST 2011


On Monday 16 May 2011 17:13:53 Michael Cirineo wrote:
> I'm able to get my iPXE client to complete a DHCP request and boot when it
>  is connected directly to my DHCP/boot server.  It's only when I put the
>  network between them that the DHCP exchange fails.  Wireshark tells me
>  everyone receives everything, but since the client sends out a second
>  DHCPREQUEST before the first DHCPOFFER reaches it, I'm thinking that the
>  DHCPREQUEST is timing out and resending, and invalidating any OFFERs that
>  come based on that first packet.  Is that possible?  Is there any way to
>  change the timeout time for a DHCPREQUEST?

I think iPXE should accept a DHCPOFFER that comes even after it times out and 
retransmits a DHCPDISCOVER.

You can use the "ifstat" command (http://ipxe.org/cmd/ifstat) to see how many 
packets iPXE thinks it has received, and what errors (if any) it encountered 
in trying to process them.

You can also use the "seconds elapsed" field in the DHCP packets transmitted by 
iPXE to see some metadata regarding the internal state of the DHCP client - 
see the DHCP "timed out" error page at http://ipxe.org/4c106035 for details.

You can also build iPXE with DEBUG=dhcp to enable DHCP debugging.

Any of those may help.

Michael


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