ISC Dhcp Failover behavior for INIT-REBOOT scenario

David W. Hankins dhankins at
Tue Jun 8 23:01:10 UTC 2010

On Thu, May 20, 2010 at 08:39:59PM +0530, ravi kumar wrote:
> I would like to know the behavior of Dhcp Failover implementation in
> INIT-REBOOT scenario. Is the following highlighted part taken care of in
> Failover implementation ?

So far as I'm aware, it works as advertised; the client in the
described scenario is given an address out of the surviving server's

> Also, would like to know if anyone has come across any Client, that behaves
> in below specified manner : Request is sent during INIT-REBOOT, though
> Client doesnot have valid lease.

I don't know of many clients that do not send INIT-REBOOTs.  Clock
skew on the client can easily cause them to send requests even when
they're not valid anymore.  So that makes it pretty much all clients
can send INIT-REBOOTs for addresses they don't have valid leases for
anymore.  We can imagine some send INIT-REBOOTs for expediency even
when they know the lease is invalid (or because they can't keep a
clock across reboots).

David W. Hankins	BIND 10 needs more DHCP voices.
Software Engineer		There just aren't enough in our heads.
Internet Systems Consortium, Inc.
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