Failover + PXE

Glenn Satchell Glenn.Satchell at
Sat Nov 24 22:36:58 UTC 2007

>Date: Sat, 24 Nov 2007 18:06:35 +0100
>From: Sten Carlsen <sten at>
>To: dhcp-users at
>Subject: Re: Failover + PXE
>Glenn Satchell wrote:
>> The dhcp servers communicate with each other and so keep the dhcp lease
>> information synchronised between the two servers.
>> ... deleted ...
>> Once upon a time I wrote a simple script that polled the other dhcp
>> server and switched to partner down if it failed to contact it for 30
>> minutes. Search the archives, I'm sure it has been posted. It uses
>> OMAPI to communicate with the dhcp server.
>I came to think: is there a reason that the function of this script is
>not included in the servers?
>I mean they communicate with one another at regular intervals, they have
>to for the servers to be up to date.
>If the other server will not answer to the protocol but can be seen with
>ping or similar, we could go to partner down state immediately and even
>send a mail to the administrator?
>If all contact breaks between the two servers, you can not know if this
>is a minor network problem or a complete break down of the other server.
>Since this is not implemented yet AFAIK, is there something wrong with
>this thinking?
>Best regards
>Sten Carlsen

This type of fucntionality is very site and operating system dependant.
You've already raised many points, eg how to determine contact, time to
wait, actions, execute something, send email, log a helpdesk ticket,
etc. The underlying tools, omapi and so on, are provided, the rest
really is specific to each site.

I don't think this should be part of the core product, but I imagine
ISC could include examples in the contrib section of the distribution?


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