[Kea-users] Configuring a subnet for both static and dynamic assignment for authorized MAC addresses

[Cristina Bulfon]

Hi,

@Kenneth , yes it is.

@Darren : thanks Darren for  the “client-classes” tip ;-)  

Ciao,
Cristina 




> On 19 Jan 2026, at 01:14, Darren Ankney <darren.ankney at gmail.com> wrote:
> 
> Hi Cristina,
> 
> You almost have it.  What you want is to add a "client-class" (less
> than 3.0) or "client-classes" (3.0+) guard to the pool.
> 
> This is simple as adding a line to your configuration:
> 
> subnet4 : [
> {
>    “Id” :”1”
>     “match-client-id”: “false”,
>      “subnet”: “X.Y.Z.0/24”,
>      “pools: [
>        {
>           “pool”:  “X.Y.Z.50 - X.Y.Z.252”,
>           "client-classes": [ "KNOWN" ]
>         }
>      ]
>      “reservations-global”  : false,
>      “reservation-in-subnet” : “true"
>       “reservation-out-of-pool” : “true”,
>       “reservations”: [
>            <?include “/etc/kea/static.json” ?>
>            <?include “/etc/kea/dynamic.json”?>
>        ]
>     }
> ]
> 
> This demonstrates using the special class "KNOWN" as a guard
> (requiring membership in the class or classes named in the list) on
> the pool.  Clients become a member of this class because they have a
> reservation. These special classes are explained here:
> https://kea.readthedocs.io/en/stable/arm/classify.html#built-in-client-classes
> This method (guarding pool assignment by specifying a client class
> that the client must be a member of) is covered here:
> https://kea.readthedocs.io/en/stable/arm/dhcp4-srv.html#pool-selection-with-client-class-reservations
> Some more related information in the ARM here:
> https://kea.readthedocs.io/en/stable/arm/dhcp4-srv.html#host-reservations-as-basic-access-control
> 
> Thank you,
> Darren Ankney
> 
> On Sun, Jan 18, 2026 at 9:51 AM Cristina Bulfon
> <cristina.bulfon at roma1.infn.it> wrote:
>> 
>> Ciao,
>> 
>> Thanks for the answer.
>> Maybe I described it incorrectly.
>> What I would like is to configure a DHCP server that assigns IPs (I defined it as "dynamic" because there is no fixed correspondence between MAC and IP) only to a pre-established list of MAC addresses.
>> 
>> Thanks,
>> Cristina
>> 
>>> On 18 Jan 2026, at 00:00, Francis Dupont <fdupont at isc.org> wrote:
>>> 
>>> IMHO you do not need to create host reservations for "dynamic" clients
>>> (and old versions of Kea required host reservations to have something
>>> different e.g. a reserved address).
>>> 
>>> Thanks
>>> 
>>> Francis Dupont <fdupont at isc.org>
>>> 
>> 
>> 
>> --
>> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
>> 
>> To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users.
>> Kea-users at lists.isc.org
> -- 
> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
> 
> To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users.
> Kea-users at lists.isc.org