[gPXE] How to modify the code can not get DHCP information on the2nd

[Gene Cumm]

2010/11/6 sqwbwh <sqwbwh at 126.com>:
> Gene Cumm
>
> thank you let I see reasons for this situation occurs.
> Want to solve this problem. How to do that?

Forcing your DHCP server to always return option 17 is application specific.

http://etherboot.org/wiki/howtos#how_to_use_advanced_dhcp_options

http://etherboot.org/wiki/appnotes/pxelinux_tftp_to_http_migration#original_dhcpd_setup

This person forcibly appended 3a and 3b to
dhcp-parameter-request-list.  This is what you'll need to do.  I think
it's a single byte in hex so 11 should be your option 17 decimal.

-- 
-Gene

> At 2010-11-07 02:49:03，"Gene Cumm" <gene.cumm at gmail.com> wrote:
>
>>2010/11/6 sqwbwh <sqwbwh at 126.com>:
>>> Miller, Shao
>>> use Embedded script
>>> "
>>> #!gpxe
>>> set use-cached 1
>>> "
>>> GPXE not have access to 017 settings
>>> How can either use the set use-cached 1
>>> Also get 017 information?
>>
>>Your native PXE client probably did not request it and/or ignored it
>>when storing the cached DHCP packets.  If you do a packet capture
>>(very easy in a hosted VMware environment), I'd guess you probably
>>won't see option 17 in the response from the server.  It is possible
>>to configure some DHCP servers to always return certain options.
>>
>>However, when you don't "set use-cached 1", the DHCP server is
>>probably sending it because gPXE is probably requesting it.
>>
>>> info:
>>> ------------
>>> Dhcp server set up in the 017 options iscsi: 192.168.0.222:: 3260:: test
>>> ------------
>>>   I set it in an embedded script:
>>> #!gpxe
>>> set use-cached 1
>>> autoboot
>>> please see 0171.jpg
>>> -0172.jpg root-path is nothing
>>>  0172.jpg is add script :
>>> #!gpxe
>>> set use-cached 1
>>> config
>>> -
>>> normal.jpg is no script
>>>
>>>
>>>
>>> At 2010-11-05 21:13:33，"Miller, Shao" <shao.miller at yrdsb.edu.on.ca> wrote:
>>>
>>>>________________________________________
>>>>From: gpxe-bounces at etherboot.org [mailto:gpxe-bounces at etherboot.org] On Behalf Of sqwbwh
>>>>Sent: Friday, November 05, 2010 09:05
>>>>To: GPXE Mailing List
>>>>Subject: [gPXE] How to modify the code can not get DHCP information on the2nd
>>>>
>>>>
>>>>How to modify the code can not get DHCP information on the 2nd?(GPXE only used to boot the system from ISCSI)
>>>>Is to remove this step.
>>>>net0: 00:0 c:: 29:08:11:35 on UNDI-PCI02: 01.0 (OPEN)
>>>>  [Link: up, TX: 0 TXE: 0 TX: 0 rxe: 0]
>>>>DHCP (net0 00:0 c: 29:08:11: d5 ).... ok
>>>>net0: 192.168.0.202/255.255.255.0
>>>>
>>>>This can speed up boot speed.
>>>>Normal GPXE run to start from the boot system tftp process takes about 8 seconds or so
>>>>If removed from the second time for DHCP information will only need a very quick 2.5 seconds.
>>>>
>>>>-----
>>>>
>>>>You most likely want the 'use-cached' option.  It is DHCP gPXE encapsulated option number 178.  Or, you can set it in an embedded script:
>>>>
>>>>  #!gpxe
>>>>  set use-cached 1
>>>>  autoboot
>>>>
>>>>- Shao Miller