[Kea-users] Subdividing a subnet based on class

[Francis Dupont]

"Sutherland, Rob" writes:
> The reason why I'm looking to this has to do with ISC DHCPd behavior (aside=
> : I'm sure that you are tired of hearing "But that's what DHCPd does!"). Co=
> nsider this example of DHCP configuration from a production server:
> 
>    subnet 10.64.5.0 netmask 255.255.255.0
>    {
>       # This is the main IP address for the router
>       option routers 10.64.5.1;
>       # Start Site DHCP Options
>       option time-offset -18000;
>       option domain-name-servers 10.64.0.141;
>       option ntp-servers 10.64.0.118;
>       # End Site DHCP Options
>       pool
>       {
>          range 10.64.5.26 10.64.5.200;
>          allow members of "phones";
>       }
>       pool
>       {
>          range 10.64.5.202 10.64.5.242;
>          deny members of "phones";
>       }
>    }
> 
> The subnet (10.64.5.0/24) is subdivided (arbitrarily) into separate pools. =
> Is there a way of getting comparable behaviour from Kea?

=> not yet: the code supporting client class in pools is under review so
is not merged. BTW we should redesign client classes code so it will be
more "not member(phone)" class than "deny" (it is a matter of taste but
IMHO it is clearer and more powerful to be able to combine classes than
to reproduce the ISC DHCP allow/deny).

Thanks

Francis Dupont <fdupont at isc.org>

PS: translation of the ISC DHCP config to Kea should give:

{
  /// This configuration declares some subnets but has no interfaces-config
  /// Reference Kea #5256
  "Dhcp4": {
    "subnet4": [
      {
        "subnet": "10.64.5.0/24",
        "option-data": [
          # This is the main IP address for the router
          {
            "space": "dhcp4",
            "name": "routers",
            "code": 3,
            "data": "10.64.5.1"
          },
          # Start Site DHCP Options
          {
            "space": "dhcp4",
            "name": "time-offset",
            "code": 2,
            "data": "-18000"
          },
          {
            "space": "dhcp4",
            "name": "domain-name-servers",
            "code": 6,
            "data": "10.64.0.141"
          },
          {
            "space": "dhcp4",
            "name": "ntp-servers",
            "code": 42,
            "data": "10.64.0.118"
          }
        ],
        "pools": [
          # End Site DHCP Options
          {
            "pool": "10.64.5.26 - 10.64.5.200"
            /// From:
            ///   allow phones
            "client-class": "phones"
          },
          {
            "pool": "10.64.5.202 - 10.64.5.242"
            /// From:
            ///   deny phones
            "client-class": "gen#_AND_#!phones#"
          }
        ]
      }
    ],
    "client-classes": [
      {
        "name": "gen#_AND_#!phones#",
        "test": "not member('phones')"
      }
    ]
  }
}