Re: [Etherboot-users] REQUIRE_VCI_ETHERBOOT Question

[<lo...@ou...>]

Hi Jim,

I see what you are saying and this all looks like a very limiting 
factor of DHCP.

Let me ask you this, ok.

When a boot client does a broadcast for a DHCP request, then there 
could be more than 1 DHCP server responding and the client would 
receive requests from all responding DHCP servers looking for the one 
that accepted that particular client and gave it a lease, right?

Would this also mean that, in general, for all of the DHCP servers, 
then if only one of the had the client MAC address in their list then 
that would be the request that would have the valid information (IP, 
gateway, etc....) for that client?

I guess what I am getting at is that it is probably ok for there to be 
multiple DHCP servers on the net and subnets as long a only one of them 
had the client address as an acceptable MAC address.

The problem with changing ports for the DHCP server and Etherboot is 
that there might already be other DHCP servers on those ports without 
us bing aware of it by some chance and then we would still have 
multiple requests beign fielded by multiple DHCP servers and in which 
the problem is really not solved.

Thanks and have a good day,

Lonnie T. Cumberland
OutStep Technologies Incorporated

Email: Lo...@ou...
       Lon...@ya...

Recommended sites:

        http://www.peoplesquest.com



Quoting Jim McQuillan <ja...@Mc...>:

> Lonnie,
>
> While it's true that you can configure Etherboot to set the 
> 'REQUIRE_VCI_ETHERBOOT' option, it won't do everything you think it 
> will.
>
> The problem is, booting an LTSP workstation involves 2 DHCP requests. 
>  The first one is from the bootrom (Etherboot OR PXE).  The 2nd DHCP 
> request comes from dhclient inside the initrd that is downloaded 
> along with the kernel.  That 2nd DHCP request won't do the 
> 'REQUIRE_VCI_ETHERBOOT' option, it will simply make a DHCP request 
> and accept the first response, no matter which dhcp server offers 
> that response.  Then, it'll fail, if the wrong server offers it, 
> because the wrong server probably isn't sending a 'root-path' value.
>
> You might instead try to set your LTSP dhcp to use ports 1067/1068, 
> instead of the standard 67/68.  That way, the workstation will make a 
> request, and the only DHCP server that will ever see the request is 
> the LTSP dhcp server.
>
> To use ports 1067/1068, there are 3 places you'll have to make a change:
>
>  1)  The etherboot bootrom configuration
>  2)  In the dhcpd.conf file, you'll have to set 'DPORT=1067' in an 
> 'option-129' field.
>  3)  You'll have to tell your dhcpd to ONLY listen on port 1067
>
> Take a look at:  
> http://wiki.ltsp.org/twiki/bin/view/Ltsp/DHCP#Multiple_DHCP_servers_on_the_sam
> for more information.
>
> ALSO, keep in mind, that using Ports 1067/1068 is ONLY an option for 
> Etherboot.  You can't do this with PXE.
>
> Hope that helps,
>
> Jim McQuillan
> ja...@Lt...
>
>
>
> Lonnie Cumberland wrote:
>> Greetings All,
>>
>> I am trying to figure out how to set up a floppy boot image so that 
>> I can boot a LTSP client but take advantage of possibly 
>> "*REQUIRE_VCI_ETHERBOOT*" and not loose the MAC address as well.
>>
>> The problem is that we have multiple DHCP servers and need to the 
>> client to ignore all requests except from a specific one that is 
>> located on another subnet.
>>
>> I have been told that there is supposed to be a way for me to add in 
>> an additional string of information into the floppy boot rom and 
>> also on my DHCP server so that when the client nic receives a 
>> response from the correct server then it will check for this string 
>> as well.
>>
>> If this is possible, then I would like to be able to specify my own 
>> string and not some default one like "Etherboot" which what I have 
>> read seems to be in the documentation.
>>
>> Can anyone please tell me more about this?
>>
>> Thanks and have a good day,
>>
>> Lonnie T. Cumberland
>> OutStep Technologies Incorporated
>>
>> Email: Lo...@ou...
>>       Lon...@ya...
>> Recommended sites:
>>     http://www.peoplesquest.com
>>
>>
>>
>>
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