[Kea-users] Overlapping Subnets

[Matt Aiken]

I am hoping someone count point me in the right direction or tell me I'm headed towards a dead-end with setting up overlapping subnets in Kea.  I saw in the ARM for the version I am using, 2.6.0, that overlapping subnets are supported however I am getting an error from kea-dhcp4 daemon that states "...shared-networks: subnet with the prefix of '192.0.2.0/24' already exists", with the configuration I have below.

I've tried with and without placing the subnets under the shared-networks object and several other adjustments, the closest I can get to the desired behavior is to set one subnet up as a /23 and the other as a /24 and adjusting the pools but this does not meet my requirements.  The client-classification and everything works great.... Its just the overlapping subnets that is throwing me for a loop with my configuration.

I did find a post on the Kea user mailing list from 2017, but it was left unanswered.

{
"Dhcp4" : {
    "client-classes" : [
        {
            "name" : "red",
            "test" : "substring(option[82].option[151].hex,1,all) == 'red'"
        },
        {
            "name" : "blue",
            "test" : "substring(option[82].option[151].hex,1,all) == 'blue'"
        }
    ],
    "shared-networks" : [
        {
            "name" : "red-192-0-2",
            "subnet4": [
                {
                    "id" : 1000,
                    "client-class" : "red",
                    "subnet": "192.0.2.0/24",
                    "pools": [{ "pool": "192.0.2.100 - 192.0.2.200" }],
                    "option-data" : [
                        { "name" : "routers", "data" : "192.0.2.1" },
                    ]
                }
            ]
        },
        {
            "name" : "blue-192-0-2",
            "subnet4" : [
                {
                    "id" : 1001,
                    "client-class" : "blue",
                    "subnet": "192.0.2.0/24",
                    "pools": [{ "pool": "192.0.2.100 - 192.0.2.200" }],
                    "option-data" : [
                        { "name" : "routers", "data" : "192.0.2.1" }
                    ]
                }
            ]
        }
    ]
}
}
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