[Kea-users] dhcp lease question

[Darren Ankney]

Hi Jason,

This has come up before.  The short answer is that ISC DHCP did not
record a lease for addresses reserved with "fixed-address".  Kea does
record a lease, and so won't allow assignment to a new client until
the lease is expired.  You could send a release from the old computer
before shutting it down, that should end the lease and make available
to the new.  You could also use the "lease4-del" API command
(https://kea.readthedocs.io/en/kea-2.4.1/arm/hooks.html#the-lease4-del-lease6-del-commands)
to remove the lease which would also make it available to the new
client.

Thank you,
Darren Ankney

On Wed, Mar 6, 2024 at 5:44 PM Jason Keltz <jas at yorku.ca> wrote:
>
> Hi.
>
> I have one question with respect to leases with Kea.
>
> On a subnet, I have assigned a static IP address for each ethernet address.  It works great.  Recently, we started replacing the computers in one of our labs.  The new computers will be replacing existing computers, so they will take on the same names.   Before we install a new machine, we turn off the old machine, reconfigure the ether address for the host in kea, and have kea re-read it's config file.
>
> When the new system comes up, Kea doesn't want to give it the ether address that is reserved for it because it sees a conflict.  Of course the IP is already issued to the old computer (that is now off).
>
> Is there an option to tell Kea to be "less particular" about leases for reservations?   That is, if the config file says that ether address X gets IP address Y, then ether address X is always going to get IP address Y whether the lease database says that it's in use or not.  Obviously we aren't going to have the old and new computer up at the same time.
>
> Is this possible?
>
> We did these kind of upgrades all the time with ISC DHCPd, and this was never an issue, so hopefully it's just an option that I'm missing.
>
> Jason.
>
>
>
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