[Kea-users] dhcp6 and ntp-server, version 3.0.3

[Darren Ankney]

Hi Charly,

That is good information.  From your testing, it seems the way that
clients have implemented the option (one option with multiple sub
options) will not support the way Kea has implemented it (multiple
options with a single sub option each).  But this is the very area of
ambiguity in the RFC.

Also, IANA specifies that option 56 should be a singleton option
(https://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xhtml#dhcpv6-parameters-2)
so there is also ambiguity between the RFC (says that multiple copies
of the option can be added) and what IANA has specified in their table
of information.

Please do respond here with the link when you've opened the issue.
Those following along on the list would probably be interested.

Thank you,
Darren Ankney

On Mon, May 4, 2026 at 3:11 PM Karl Gaissmaier
<karl.gaissmaier at uni-ulm.de> wrote:
>
> Hi Darren,
>
> next test with *dnsmasq' and *systemd-networkd* as dhcp client.
>
> tl;dr, systemd-networkd is also able to parse more than one
> suboption-id-1 in one option-56 container:
>
> tshark -V
> >     NTP Server
> >         Option: NTP Server (56)
> >         Length: 60
> >         NTP Server Address
> >             Suboption: NTP Server Address (1)
> >             Length: 16
> >             NTP Server Address: 2001:db8::77
> >         NTP Server Address
> >             Suboption: NTP Server Address (1)
> >             Length: 16
> >             NTP Server Address: 2001:db8::88
> >         NTP Server Address
> >             Suboption: NTP Server Address (1)
> >             Length: 16
> >             NTP Server Address: 2001:db8::99
>
> > # networkctl status eth0
> > ...
> >
> >                          NTP: 2001:db8::77
> >                               2001:db8::88
> >                               2001:db8::99
>
> Best regards
>     Charly
>
> --
> Karl Gaissmaier
> Universität Ulm
> kiz, Kommunikations und Informationszentrum
> 89069 Ulm
> Tel.: 49(0)731/50-22499
>
>
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