[Kea-users] from isc dhcp classes -> kea 3.0

[Gregor Kling]

Hi Darren,

On 11/21/25 4:38 PM, Darren Ankney wrote:
> Hello Gregor,
>
>> Hi Darren,
>>
>> Deciding the reservation model
>>
>> 9.3.9. Global Reservations in DHCPv4 describes in general our
>> setup. Clients generally can roam in our network based on the
>> attributed "pool class" to the specific mac address and the
>> "accessability" of the specific network.
>>
>> The following section:
>>
>> #+begin_quote 9.3.9. Global Reservations in DHCPv4:
>> An address assigned via global host reservation must be feasible for the
>> subnet the server selects for the client. In other words, the address
>> must lie within the subnet; otherwise, it is ignored and the server will
>> attempt to dynamically allocate an address. If the selected subnet
>> belongs to a shared network, the server checks for feasibility against
>> the subnet's siblings, selecting the first in-range subnet. If no such
>> subnet exists, the server falls back to dynamically allocating the address.
>> #+END_quote
> This is generally true, but you are not (as far as I understood)
> assigning an address to the clients in the reservation and instead are
> selecting a pool for them to use for a dynamic address with the
> reservation (by adding the client to one or more classes and using a
> class guard on the pools).

Generally true - yes - but with the following exception.

Again given the following setup. When  the host with the 
mac "a1:bb:cc:dd:ee:ff" visits his "homebase",

subnet id 1 it should be given the  "ip-address": "10.0.0.2" and not a 
pool address.

Should this host however visit, for example subnet id 2, it should be 
given a pooladdress.

So the the question remains (on this blurry monday morning) - which 
reservation model should i use?

#+begin_quote
{
"Dhcp4": {
         "client-classes": [{
             "name": "pool_name_1",
             "valid-lifetime": 3600
         },
         {
             "name": "pool_name_etc",
             "valid-lifetime": 3600
         },
         ],
         "subnet4": [
         {
           "id": 1,
           "subnet": "10.0.0.0/24",
           "pools": [
                         {
                           "pool": "10.0.0.10-10.0.0.100",
                           "client-classes": ["pool_name_1", 
"pool_name_etc"]
                         }
           ],
           "reservations": [
           {
               "hw-address": "a1:bb:cc:dd:ee:ff",
               "ip-address": "10.0.0.2",
               "client-classes": [ "pool_name_1", "pool_name_etc" ]

           },
           {
               "hw-address": "a2:bb:cc:dd:ee:ff",
               "ip-address": "10.0.0.3",
               "client-classes": [ "pool_name_etc" ]

           }

         ]
       },
       {
         "id": 2,
         "subnet": "192.0.3.0/24",
         "pools": [
             {
                 "pool": "192.0.3.10-192.0.3.20",
                 "client-classes": [ "pool_name_1" ]
             },
         ],
          "reservations": [
           {
               "hw-address": "a1:bb:cc:dd:ee:ff",
               "client-classes": [ "pool_name_1", "pool_name_etc" ]

           },
           {
               "hw-address": "a2:bb:cc:dd:ee:ff",
               "client-classes": [ "pool_name_etc" ]

           }

         ]

     }
]

}

}

#+end_quote


-- 

Gregor Kling

Abteilung ITS, Sachgebiet ITS-N
Technische Hochschule Mittelhessen
University of Applied Sciences
Tel: 0641/309-1292
E-Mail: gregor.kling at its.thm.de

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