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

[sqwbwh]

Shao Miller
i do 3.jpg and 4.jpg
but no success
If the screenshots just fine.Like http://etherboot.org/wiki/msdhcp # setting_up_a_gpxe_encapsulated_options_on_windows_dhcp
The hyperlink is the CHAP user and password to understand
178 still do not understand.
-sqwbwh

 

At 2010-11-05 23:42:16，"Shao Miller" <Shao.Miller at yrdsb.edu.on.ca> wrote:
sqwbwh wrote:At 2010-11-05 23:13:19，"Shao Miller" <Shao.Miller at yrdsb.edu.on.ca> wrote:
sqwbwh wrote:At 2010-11-05 22:39:05，"Shao Miller" <Shao.Miller at yrdsb.edu.on.ca> wrote:
sqwbwh wrote:


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.

Miller, Shao wrote:
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
Gene Cumm wrote:

What file and version are you using?  It sounds as if you're using
undionly.kpxe or a .pxe file.  undionly.kkpxe will skip this second
DHCP request but certain hardware/firmware has issues with this,
assuming you trust the stability of your OEM's PXE/UNDI stack.

sqwbwh wrote:
Shao Miller

The method is successful.
Thank you
sqwbwh wrote:
yes
thankyou  Shao Miller
Your method is useful ：）
Miller, Shao wrote:
You’re quite welcome, and thanks for including the list on your other reply. :)  Have a nice day.  - Shao
sqwbwh wrote:
Shao Miller
1:
i use :
" set it in an embedded script:

#!gpxe
set use-cached 1
autoboot
it's good
2:
"It is DHCP gPXE encapsulated option number 178"
Specifically to ask how to use this method?
What can explain it in detail?
thank~you
I enjoy using the search feature at the gPXE (Etherboot) wiki.  Please see:

http://etherboot.org/wiki/doku.php?do=search&id=encapsulated&fulltext=Search
http://etherboot.org/wiki/msdhcp
http://etherboot.org/wiki/dhcpd
Shao Miller
Use the search function.
Use hyperlinks to provide you with three options for the introduction of 178 not found.
178 keyword search does not find use-cached search did not find the relevant presentation.

Hehe.Could you give me the answer it?.English is almost a maze for me


I'm afraid that I'm not sure how to explain gPXE encapsulated options any better than they are explained in the wiki.  DHCP option 175 should be a string of bytes.  Within that byte sequence, there are sub-options.  'use-cached' is sub-option 178.  So your DHCP option 175 could look like:

0xB2 0x01 0x01

where,

0xB2 : DHCP gPXE encapsulated option 178.
0x01 : The encapsulated option's value occupies 1 byte.
0x01 : The encapsulated option's value is 1 (true).

I do not know which DHCP service you use, so I do not know how you can reconfigure your service to give PXE clients this 'use-cached' option via DHCP.Shao Miller
dhcp server is msdhcp
Use 1781.jpg and 1782.jpg is set.Enable use-cached did not succeed
Picture shows what can it?

Those screen-shots show a DHCP option 178, not a DHCP gPXE encapsulated option 178.

You need DHCP option 175.  _Inside_ option 175, you need to have gPXE encapsulated option 178.  See:

http://etherboot.org/wiki/msdhcp#setting_up_a_gpxe_encapsulated_options_on_windows_dhcp

It shows exactly how to create the DHCP gPXE encapsulated options.  175 is a _container_.  178 ('use-cached') goes inside that container.  Change to option 175 and you will be fine, since your bytes are exactly as I explained above: Option 178, 1 byte long, value 1.  All gPXE encapsulated options go inside option 175.  0xB2 means 178.

Please remember to carbon-copy the list using Reply-All.

- Shao Miller
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