[Kea-users] Host reservation "hostname"

[Marcin Siodelski]

On 06.09.2016 18:02, Patrik Lundin wrote:
> On Mon, Sep 05, 2016 at 06:08:38PM +0200, Marcin Siodelski wrote:
> >
> > Kea 1.0.0 supports hostname reservations for both DHCPv4 and DHCPv6.
> > However, the general rule is that the servers won't send back hostname
> > or client fqdn option back to the client if DNS updates are disabled.
> >
> > See http://kea.isc.org/docs/kea-guide.html#dhcp4-ddns-config for
> details.
> >
> > This rule also applies to statically assigned/reserved hostnames. We may
> > need to improve the doc to make it more clear. The question is, though,
> > whether you have some use case when the hostnames need to be returned to
> > the clients when DNS updates are off?
> >
>
> My specific usecase is for the OpenBSD installer. It primes the machine
> hostname with the content of the host-name DHCP option if it is present.
> Currently I work around it by having a CGI script generate the response
> file requested by the autoinstall system, where the hostname is parsed
> out of the kea.conf JSON file on the fly.
>

In your use case, do DHCP clients send Hostname option to the server or
they rather only include Hostname option code in the Parameter Request
List option, or both?

> Since kea 1.1.0 will support setting options for reservations this might
> be considered good enough until then. I do agree the manual should
> mention the DDNS requirement. I got very confused since it states
> options will be synthezised, but no mention of DDNS being a requirement
> for that to happen.
>
> Another question that pops into my head with the addition of
> reservations having support for setting options: if the DDNS support
> _is_ active (meaning options are being synthezised), and an host-name
> option is also statically configured for the reservation, what will be
> used in the packet sent to the client?
>

In that case, the statically reserved option (from host reservations)
will take precedence over any other option value (either generated or
the one proposed by a client).

Marcin