giving bootp request ONLY once

Glenn Satchell Glenn.Satchell at
Wed Jun 14 12:00:06 UTC 2006

>Date: Wed, 14 Jun 2006 16:35:44 +0530
>From: Yayati Singh <yayatisingh at>
>To: dhcp-users at
>Subject: Re: giving bootp request ONLY once
> Simon Hobson wrote: Yayati Singh wrote: I have a typical scenario, where
>thebootp info needs to be served ONLY once. An typical usage would be
>installing windows,where windows reboots three times, and for the rest of
>thetime dhcpd need not server the client with any bootp info. Any work
>aroundon dhcpd or hack to its code would be helpfull. I don't follow, why
>don't you want to service this client more than once ? Do you really mean
>bootp, or dhcp ? What are you trying to achieve ? I meant bootp, 
>Since every time the machine would boot it would get a bootp directive and
>start re-installing the OS ( i use pxe ). So i have to sit down on the
>machine console every time it reboots for the first time and do the
>#1 change the boot order in the BIOS, to boot from the hardisk.
>#2  Change the dhcp.conf and comment the particular host, restart dhcpd.
>i want to avoid all these and do an un-attended installation of OS when
>needed, without sitting on the console to do some manual intervention in
>preventing the machine going in a reboot loop.
>The other application is we have many appliances, which we kickstart from
>time to time, but we need not always reboot the appliances with kickstarting
>in mind, so on post install on the first reboot we have to manually disable
>PXE boot on the appliances. This whole process gets painfull.  We wanted to
>see if we can control bootp from dhcpd itself. Hence controlling OS
>installations when ever needed.
>We have one method which could be a starting point, listen for dhcpd syslog
>messages for serving the particular client, and after serving the client
>message is found modify dhcpd.conf and restart dhcpd not to serve that
>clientagain. but dhcpd does not give a clean message of bootp on the syslog.
>Any more ideas ??
Hi Yayati,

So if I understand correctly you want to be able to do a pxe boot and
get a bootp response, but other times you don't want this to happen. So
it looks like you need to do one of two things:

1. modify dhcpd to not respond to a particular host

2. modify the client to not try to do a net boot.

Perhaps using omapi (try man omapi, and man omshell for examples) to
add and remove hosts would be one way. At least this doesn't require
stopping and starting dhcpd. You could also create a couple of wrapper
scripts to add and remove arbitrary hosts before net booting and


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