[K12OSN] DHCP on a different port..... thanks.

Bert Rolston bert.rolston at clear.net.nz
Thu Dec 28 23:16:42 UTC 2006

Hi Folks,

Thanks for your help Jim, Huck, David, and Chuck.

I'll be using etherboot images. AFAIK I can get these burnt onto
Is this correct? 
If so then PXE is a moot point. 

I know how to put etherboot onto floppy.
I have toyed with the idea of IDE to CF adaptors and putting 
etherboot on CF.
Another altenative is etherboot CD's.

In this case I will probably use the old HDD's in the machines which are
all less than 1GB.

I don't have access to the MS DHCP server. Abut two weeks ago I asked
the list about passing requests through the MS DHCP server to the LTSP
DHCP server.

The sysadmin I am dealing with clearly stated he doesn't want anything
to disrupt or change the current infrastructure. He uses Ubuntu at home
so introducing Linux isn't a problem. 

This installation has to be rock solid in order to change current
negative perceptions of Linux that upper level management has.

The network is running class B /16 addresses.

Thanks for your time.


> - I could run the LTSP DHCP server on a network with an MS DHCP server
> - There wouldn't be any conflicts between the two DHCP servers
> - MS clients would get their IP address from the MS DHCP server, and 
>   any LTSP terminals would get their IP address from the LTSP server
> By creating custom boot rom images on the Rom-O-Matic website that use
> the port I have chosen, the LTSP thin clients will connect to the Linux
> DHCP server, NOT the MS DHCP server.

> Therefore, in THEORY, I could put a single nic LTSP server into an
> existing MS network without any disruption to their current
> infrastructure.
> If this is the case it fits the criteria set by someone who is
> investigating the use of LTSP, and has approached me for help.
> Is my theory sound or have I missed something.

> From: Jim McQuillan <jam at mcquil.com>

> Your theory is good.  EXCEPT, it won't work with PXE bootroms.  It will 
> ONLY work with Etherboot bootroms.
> The reason is, there's no way to tell PXE to use a different port.
> If you can live with that, then you can use the alternate port method.
> Jim McQuillan
> jam at Ltsp.org

> From: Huck <dhuckaby at hvja.org>
> Theory is sound given the following layout:
> MS-DHCP server  ------>  MS-CLIENTS
>    |
>    |
>   V
> eth1
> K12LTSP  eth0   -------> LTSP clients
>             ltsp-dhcp active on THIS NIC only
> I surely wouldn't attempt this with a single NIC setup(I'm faint of 
> heart)...
> the 10/100 nic for the ETH1 is cheap enough to do a dual nic setup..
> --Huck

> From: Jim McQuillan <jam at mcquil.com>

> The whole point of his theory was that he wanted a single NIC setup.
> It works fine, nothing to be scared of.
> there's no way the MS clients will get an address from a Linux DHCP 
> server configured for a port other than 67/68
> And the thin clients won't get a response from the MS server.
> Jim.

> From: Huck <dhuckaby at hvja.org>
> Ah, I see said the blind man.
> although it seems like it'd have a greater potential for bandwidth 
> bottleneck'n...
> --Huck

> From: "David Trask" <dtrask at vcsvikings.org>
> Yep...you're right....except PXE won't work, but if that's not an issue
> you should be fine.  :-)

> From: cliebow at midmaine.com
> something tells me you have no access to ms dhcp..but you could use ms
> dhcp to pass everything including Netvista (except macintosh ibook info
> which i cant get working yet(though the bondi works fine))with winders
> dhcp.
> the only mystery we discovered was some weird print problem when option 60
> was configured globally for the entire subnet..chuck

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