From wnelto at wm.edu  Fri Oct  2 14:52:39 2026
From: wnelto at wm.edu (Elton, Norman N)
Date: Fri, 2 Oct 2026 14:52:39 +0000
Subject: [Kea-users] NAK responses getting dropped
Message-ID: <LV2PR05MB08197065085B910CDAEB615E72B1892@LV2PR05MB081970.namprd05.prod.outlook.com>

We have clients requesting addresses in the wrong subnet, which Kea is trying to send a NAK:

[kea-dhcp4.dhcp4.123] DHCP4_QUERY_LABEL received query: [hwtype=1 bc:9f:58:1b:cf:f3], cid=[01:bc:9f:58:1b:cf:f3], tid=0x6a744f8
[kea-dhcp4.packets.123] DHCP4_PACKET_RECEIVED [hwtype=1 bc:9f:58:1b:cf:f3], cid=[01:bc:9f:58:1b:cf:f3], tid=0x6a744f8: DHCPREQUEST (type 3) received from 100.70.0.2 to 128.239.10.154 on interface bond0.10
[kea-dhcp4.leases.123] DHCP4_INIT_REBOOT [hwtype=1 bc:9f:58:1b:cf:f3], cid=[01:bc:9f:58:1b:cf:f3], tid=0x6a744f8: client is in INIT-REBOOT state and requests address 100.69.0.173
[kea-dhcp4.packets.123] DHCP4_PACKET_SEND [hwtype=1 bc:9f:58:1b:cf:f3], cid=[no info], tid=0x6a744f8: trying to send packet DHCPNAK (type 6) from 128.239.10.154:67 to 100.70.0.2:67 on interface bond0.10

Problem is, the NAK is not being sent. When running packet captures, I see tons ACKs but no NAKs. The pkt4-nak-sent statistic is increasing. Just ? no packets on the wire.

I cranked up kea-dhcp4.packets to DEBUG mode, no additional information.

Kea 2.6.4 running in load-balancing high availability mode.

Any suggestions?

Thanks,

Norman Elton
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From darren.ankney at gmail.com  Fri Oct  2 22:42:41 2026
From: darren.ankney at gmail.com (Darren Ankney)
Date: Fri, 2 Oct 2026 18:42:41 -0400
Subject: [Kea-users] NAK responses getting dropped
In-Reply-To: <LV2PR05MB08197065085B910CDAEB615E72B1892@LV2PR05MB081970.namprd05.prod.outlook.com>
References: <LV2PR05MB08197065085B910CDAEB615E72B1892@LV2PR05MB081970.namprd05.prod.outlook.com>
Message-ID: <CAKabWHg+W6hb83qc3XcxUi+7H-F66OZ1fdeuuJSVPcvP1HxthQ@mail.gmail.com>

HI Norman,

Where are you capturing the packets?  Directly on the Kea server or
somewhere else?  Also, full logs and your Kea configuration would be
necessary to get a clearer picture of what might be happening.

Thank you,
Darren Ankney

On Fri, Oct 2, 2026 at 10:52?AM Elton, Norman N <wnelto at wm.edu> wrote:
>
> We have clients requesting addresses in the wrong subnet, which Kea is trying to send a NAK:
>
> [kea-dhcp4.dhcp4.123] DHCP4_QUERY_LABEL received query: [hwtype=1 bc:9f:58:1b:cf:f3], cid=[01:bc:9f:58:1b:cf:f3], tid=0x6a744f8
> [kea-dhcp4.packets.123] DHCP4_PACKET_RECEIVED [hwtype=1 bc:9f:58:1b:cf:f3], cid=[01:bc:9f:58:1b:cf:f3], tid=0x6a744f8: DHCPREQUEST (type 3) received from 100.70.0.2 to 128.239.10.154 on interface bond0.10
> [kea-dhcp4.leases.123] DHCP4_INIT_REBOOT [hwtype=1 bc:9f:58:1b:cf:f3], cid=[01:bc:9f:58:1b:cf:f3], tid=0x6a744f8: client is in INIT-REBOOT state and requests address 100.69.0.173
> [kea-dhcp4.packets.123] DHCP4_PACKET_SEND [hwtype=1 bc:9f:58:1b:cf:f3], cid=[no info], tid=0x6a744f8: trying to send packet DHCPNAK (type 6) from 128.239.10.154:67 to 100.70.0.2:67 on interface bond0.10
>
> Problem is, the NAK is not being sent. When running packet captures, I see tons ACKs but no NAKs. The pkt4-nak-sent statistic is increasing. Just ? no packets on the wire.
>
> I cranked up kea-dhcp4.packets to DEBUG mode, no additional information.
>
> Kea 2.6.4 running in load-balancing high availability mode.
>
> Any suggestions?
>
> Thanks,
>
> Norman Elton
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