Return ignore during dhcprequest for unknown subnets

[Darren Ankney]

Hi Philipp,

You would probably get more responses about kea on kea-users:
https://lists.isc.org/mailman/listinfo/kea-users

That being said, In your Kea configuration, do you have this?
"authoritative": true

If so, either remove it or explicitly set it false: "authoritative": false

See here for further details:
https://kea.readthedocs.io/en/kea-2.4.1/arm/dhcp4-srv.html#authoritative-dhcpv4-server-behavior

Thank you,
Darren Ankney

On Tue, Jun 4, 2024 at 2:13 AM Jan-Philipp Snizek
<jan-philipp.snizek at business.uzh.ch> wrote:
>
> Hi
>
>
>
> Isc-dhcpd ignores dhcprequest from clients that come from an unknown segment. In the logs it looks like this:
>
>
>
> DHCPREQUEST for 10.65.1.179 from MAC:ADDR via 10.65.0.1: ignored (unknown subnet).
>
>
>
> What I get from kea-dhcp4 is this:
>
>
>
> ERROR [kea-dhcp4.bad-packets/435270.139990395717376] DHCP4_PACKET_NAK_0001 [hwtype=1 MAC:ADDR], cid=[MAC:ADDR], tid=0x52eec91a: failed to select a subnet for incoming packet, src 10.65.0.1, type DHCPREQUEST
>
> ERROR [kea-dhcp4.bad-packets/435270.139990395717376] DHCP4_PACKET_NAK_0001 [hwtype=1 MAC:ADDR], cid=[MAC:ADDR], tid=0x52eec91b: failed to select a subnet for incoming packet, src 10.65.0.1, type DHCPDISCOVER
>
>
>
> Kea sends dhcpnak to clients from subnets it is not configured to serve. If the same client keeps coming back, it will not get an IP address. This is what is happening.
>
> It would be very helpful if kea would ignore these requests, much like isc-dhcp does. Is it possible to configure this?
>
>
>
> I am aware of dhcp helpers. There would be no such logs if we had dhcp helpers in our network. Currently, we don’t. Our network guys work (and the hardware vendor) work on it.
>
>
>
> Thanks,
>
> Philipp
>
> --
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users