[ipxe-devel] [gPXE] Debugging over UDP

Vinay Venkataraghavan raghavanvinay at yahoo.com
Wed Dec 8 20:09:59 UTC 2010

Looks like I setup the interface on the host that I want to PXE boot correctly. 
I am also able to ping it from the host machine on which I want to run the 
debugger. However, I am unable to ping the client once I run the command 
"gdbstub udp net0" on the client..

Any thoughts? 
- 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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