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// This is an example configuration file for the DHCPv4 server in Kea.
// It demonstrates how global host reservations can be configured.
// The global reservations are not associated with any subnet. They
// are assigned regardless of the subnet to which the DHCP client belongs.
// Global reservations are assigned to the DHCP clients using the
// same host identifier types as subnet specific reservations. This file
// contains multiple examples of host reservations using different
// identifier types, e.g. MAC address, client identifier etc.
{ "Dhcp4":
{
// Kea is told to listen on eth0 interface only.
"interfaces-config": {
"interfaces": [ "eth0" ]
},
// We need to specify the database used to store leases. As of June
// 2022, three database backends are supported: MySQL, PostgreSQL and
// the in-memory database, Memfile. We'll use memfile because it doesn't
// require any prior set up.
"lease-database": {
"type": "memfile",
"lfc-interval": 3600
},
// Addresses will be assigned with a lifetime of 4000 seconds.
"valid-lifetime": 4000,
// Renew and rebind timers are commented out. This implies that options
// 58 and 59 will not be sent to the client. In this case it is up to
// the client to pick the timer values according to RFC2131. Uncomment the
// timers to send these options to the client.
// "renew-timer": 1000,
// "rebind-timer": 2000,
// Kea supports reservations by several different types of identifiers:
// hw-address (hardware/MAC address of the client), duid (DUID inserted by the
// client), client-id (client identifier inserted by the client), circuit-id
// (circuit identifier inserted by the relay agent) and flex-id (flexible
// identifier available when flex_id hook library is loaded). When told to do
// so, Kea can check for all of those identifier types, but it takes a costly
// database lookup to do so. It is therefore useful from a performance
// perspective to use only the reservation types that are actually used in a
// given network.
// The example below is not optimal from a performance perspective, but it
// nicely showcases the host reservation capabilities. Please use the minimum
// set of identifier types used in your network.
"host-reservation-identifiers": [ "circuit-id", "hw-address", "duid",
"client-id", "flex-id" ],
// This directive tells Kea that reservations are global. Note that this
// can also be specified at shared network and/or subnet level.
// "reservation-mode": "global",
// It is replaced by the "reservations-global", "reservations-in-subnet", and
// "reservations-out-of-pool" parameters.
// Specify whether the server should look up global reservations.
"reservations-global": true,
// Specify whether the server should look up in-subnet reservations.
"reservations-in-subnet": false,
// Specify whether the server can assume that all reserved addresses
// are out-of-pool.
// Ignored when reservations-in-subnet is false.
// If specified, it is inherited by "shared-networks" and "subnet4" levels.
"reservations-out-of-pool": false,
// Define several global host reservations.
"reservations": [
// This is a reservation for a specific hardware/MAC address. It's a very
// simple reservation: just an address and nothing else.
// Note it is not recommended but still allowed to reverse addresses at
// the global scope: as it breaks the link between the reservation and
// the subnet it can lead to a client localized in another subnet than
// its address belongs to.
{
"hw-address": "1a:1b:1c:1d:1e:1f",
"ip-address": "192.0.2.201"
},
// This is a reservation for a specific client-id. It also shows
// the this client will get a reserved hostname. A hostname can be defined
// for any identifier type, not just client-id. Either a hostname or
// an address is required.
{
"client-id": "01:11:22:33:44:55:66",
"hostname": "special-snowflake"
},
// The third reservation is based on DUID. This reservation also
// defines special option values for this particular client. If
// the domain-name-servers option would have been defined on a global,
// subnet or class level, the host specific values take precedence for
// this particular DHCP client.
{
"duid": "01:02:03:04:05",
"ip-address": "192.0.2.203",
"option-data": [ {
"name": "domain-name-servers",
"data": "10.1.1.202,10.1.1.203"
} ]
},
// The fourth reservation is based on circuit-id. This is an option inserted
// by the relay agent that forwards the packet from client to the server.
// In this example the host is also assigned vendor specific options.
{
"circuit-id": "01:11:22:33:44:55:66",
"ip-address": "192.0.2.204",
"option-data": [
{
"name": "vivso-suboptions",
"data": "4491"
},
{
"name": "tftp-servers",
"space": "vendor-4491",
"data": "10.1.1.202,10.1.1.203"
}
]
},
// This reservation is for a client that needs specific DHCPv4 fields to be
// set. Three supported fields are next-server, server-hostname and
// boot-file-name
{
"client-id": "01:0a:0b:0c:0d:0e:0f",
"ip-address": "192.0.2.205",
"next-server": "192.0.2.1",
"server-hostname": "hal9000",
"boot-file-name": "/dev/null"
},
// This reservation is using flexible identifier. Instead of relying
// on specific field, sysadmin can define an expression similar to what
// is used for client classification,
// e.g. substring(relay[0].option[17],0,6). Then, based on the value of
// that expression for incoming packet, the reservation is matched.
// Expression can be specified either as hex or plain text using single
// quotes.
// Note: flexible identifier requires flex_id hook library to be
// loaded to work.
{
"flex-id": "'s0mEVaLue'",
"ip-address": "192.0.2.206"
}
],
// Define a subnet.
"subnet4": [
{
"pools": [ { "pool": "192.0.2.1 - 192.0.2.200" } ],
"id": 1,
"subnet": "192.0.2.0/24",
"interface": "eth0"
}
],
// The following configures logging. It assumes that messages with at
// least informational level (info, warn, error and fatal) should be
// logged to stdout.
"loggers": [
{
"name": "kea-dhcp4",
"output-options": [
{
"output": "stdout"
}
],
"severity": "INFO"
}
]
}
}
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