[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 14:21:57 EDT 2010
sqwbwh wrote:
> At 2010-11-06 01:27:57，"ShaoMiller"<Shao.Miller at yrdsb.edu.on.ca> wrote:
>
> 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
> embedded script.jpg is add a script as you say
> #! Gpxe
> set use-cached 1
> autoboot
>
> Show dhcp using cached correctly
>
> 178dhcp.jpg is the DHCP settings added 0xb2 0x01 0x01 0xff
> According to this set the client to display the information is 178.jpg
> Does not correctly display dhcp using cached is not where not set
> correctly?
>
As Gene Cumm mentioned, think about which file you are using. Please see:
http://etherboot.org/wiki/pxechaining
This is the file that you are currently using:
gpxe-1.0.1-undi.pxe
- Shao Miller
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