DHCP Option (iPXE View) - Printable Version

DHCP Option (iPXE View) - Printable Version

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DHCP Option (iPXE View) - MultimediaMan - 2011-12-28 02:32

OK, I was using a Windows DHCP Server in conjunction with the Remote Boot Service for Windows Embedded: I wasn't sure what options it was offering up "under the covers". It looked a lot like DHCP Options 17 and 67, but I couldn't see those options populated with my input; so I wrote a quick and dirty little Windows script which belts out a semi-usable ipxe script: just change ",," to "&&" in a text editor...

Code:

@ECHO OFF

::Script to create DHCP option query

SETLOCAL

SET OPT_VALUE=0

ECHO #!ipxe>dhcp.ipxe

:LOOP

IF %OPT_VALUE% GEQ 254 GOTO END

SET /A OPT_VALUE=%OPT_VALUE%+1

ECHO echo %OPT_VALUE% ,, echo ${%OPT_VALUE%} ,, sleep 1 >>dhcp.ipxe

GOTO LOOP

:END

ECHO prompt>>dhcp.ipxe

ENDLOCAL

PAUSE

For the Record...what I was looking for was what the RBS handed out as far as a path and file... it used DHCP Option 253 to do the following where: %BOOTIMAGE% and %BOOTPARAMETERS% are the two variables I found in the RBS which I did not know the mechanics of: Microsoft, ever so thoughtful, did NOT document this...

Code:

[boot loader]

timeout=30

default=ramdisk(0)\windows

[operating systems]

ramdisk(0)\windows="Windows XP Embedded" /rdpath=net(0)\%BOOTIMAGE% %BOOTPARAMETERS%

Again, In the Remote Boot Server UI, these look a lot like DHCP Options 17 and 67, but alas, they are not...

RE: DHCP Option (iPXE View) - robinsmidsrod - 2012-09-28 10:13

If you have access to a packet trace that is usually much more helpful in figuring out what gets transmitted. The "config" iPXE command (http://ipxe.org/cmd/config) is also useful to see what you have.