[ipxe-devel] [gPXE] Debugging over UDP

Vinay Venkataraghavan raghavanvinay at yahoo.com
Wed Dec 8 19:50:11 UTC 2010


Thank you so much once gain for your incredibly prompt response. 

The approach that we are taking for this solution is to develop a specific 
option ROM which does not implement the full DHCP protocol etc. This option rom 
"knows" how to communicate with this management host to download PXE images and 
to boot these servers using these images. 

Thats the need motivation to try this option out.

Secondly, I just wanted to generally step through the whole code and not only 
the dhcp portion so that I familiarize myself with the different interactions 
before slimming it down to potentially only the portion that executes the stages 
to download the code and then in the backend will communicate with hosts that 
contact me for this image. 


is the sequence that I followed at the gPXE prompt to bring up and configure the 
networking interface correct? Is there something else to this. I checked the 
network interface and it is pingable. Will try this again though. 

- Vinay

----- Original Message ----
From: Michael Brown <mbrown at fensystems.co.uk>
To: Vinay Venkataraghavan <raghavanvinay at yahoo.com>
Cc: ipxe-devel at lists.ipxe.org
Sent: Wed, December 8, 2010 11:24:40 AM
Subject: Re: [gPXE] Debugging over UDP

On Wednesday 08 Dec 2010 18:58:11 Vinay Venkataraghavan wrote:
> I just recently started to play with gPXE and would like to step through
>  the process using the debugging options. But I have not been sucessful.
>  Any help would be appreciated.
> The steps I followed are as show below:
> 1. Built an iso image and burned it to a dvd.
> 2. Booted the client machine and broke into the gPXE prompt.
> 3. Executed: ifopen net0
>                    set net0/ip
>                       bdgstub udp net0
> 4. On the debugger machine.
>                 gdb
>                 set debug remote 1
>                 file bin/gpxe.lkrn.tmp
>                 target remote udp:
> Questions:
> 1) What is the name of the corresponding .tmp file to use when I am using
>  an gpxe.iso image. This is not specified in the gPXE documentation.

You want the ".lkrn.tmp" file.  (An .iso image is built using the .lkrn 

> 2) I get the following output:
> <snip>

Are you able to ping from the machine running gdb?

Also, since you say that you just recently started to play: are you aware that 
there is a substantial amount of built-in debug code that can be enabled 
without having to go to the effort of using gdb?  For example, if you are 
having problems with DHCP, then

  make bin/ipxe.iso DEBUG=dhcp

will show you debugging messages related to DHCP.  You can find some 
description of debug builds at





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