[gPXE] How to modify the code can not get DHCP information on the2nd
Shao Miller
Shao.Miller at yrdsb.edu.on.ca
Fri Nov 5 13:27:57 EDT 2010
sqwbwh wrote:
> At 2010-11-05 23:42:16，"ShaoMiller"<Shao.Miller at yrdsb.edu.on.ca> wrote:
>
> sqwbwh wrote:
>> At 2010-11-05 23:13:19，"ShaoMiller"<Shao.Miller at yrdsb.edu.on.ca>
>> wrote:
>>
>> sqwbwh wrote:
>>> At 2010-11-05 22:39:05，"ShaoMiller"
>>> <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
>>>
>>> ShaoMiller
>>> 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
> 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.
Your screen-shots look good! Except that you are missing the final
terminating 0xFF byte! At the end of all gPXE encapsulated options,
there should be a terminating byte.
0xB2 0x01 0x01 0xFF
0xFF: No more gPXE encapsulated options.
Also, what version of gPXE are you using? Please use gPXE >= 1.0.0.
Thank you again for including the mailing-list.
- Shao Miller
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