lease problem

Julie Xu xll40 at
Sat Jul 28 12:31:11 UTC 2012

Yes, it is for PXE/windown building process.
So, "deny duplicate" and "on-lease-per-client"  all can not fix the problem.
it is big issue for me now. Any way to work around? I mean to let machine keep same ip address after reboot?
I can not give all the machines a host stattement. I need them on dynomic range. 
I guess this is a common problem for everyone who use isc dhcpd and windows, any know how to fix it ether on dhcpd site or windown site?
Message: 3
Date: Sat, 28 Jul 2012 08:23:20 +0100
From: Simon Hobson <dhcp1 at>
To: Users of ISC DHCP <dhcp-users at>
Subject: Re: lease problem
Message-ID: <p06240803cc3942929f6b at>
Content-Type: text/plain; charset="us-ascii" ; format="flowed"
Julie Xu wrote:
>I get complain about new machines. the problem is :
> when new machine come online first time, it get one ip 
>address. when the machine reinstall company image and reboot, even 
>it is in 10 minutes time, it get another ip address.
let me guess, the company image is Windows, and the <something else> 
booted before that is not Windows ?
It's most likely that the first system booted does not send a 
Client-ID - this is the default for pretty much everything other than 
Then when the system is booted with Windows, a Client-ID is used.
The ISC server uses the Client-ID as the primary database key if one 
is supplied, and only falls back to the MAC (hardware) address if 
there is no Client-ID. So the two systems are different clients as 
far as the server is concerned.
There used to be some patches that would "fix" this, but I've not 
heard of them for a while and I've no idea if they are maintained. If 
not maintained, they wouldn't work (I assume) against the current 
But the obvious question is does it actually matter ?
Simon Hobson
Visit for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.
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