Adding upstream version 2.2.0.upstream/2.2.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1155 insertions, 0 deletions

diff --git a/doc/examples/kea4/all-keys.json b/doc/examples/kea4/all-keys.json
new file mode 100644
index 0000000..3b3b722
--- /dev/null
+++ b/doc/examples/kea4/all-keys.json
@@ -0,0 +1,1155 @@
+// WARNING: This example configuration is not meant for production use.
+// The Kea DHCPv4 server will refuse this configuration because it contains
+// mutually exclusive configuration parameters.
+//
+// The primary purpose of the example file is to provide a comprehensive
+// list of parameters supported by Kea DHCPv4 server along with the brief
+// description of each parameter.
+//
+// This current version should be up to date, i.e. new keywords should be
+// added in this file at the same time than in the syntax.
+{
+    // Kea DHCPv4 server configuration begins here.
+    "Dhcp4": {
+
+        // Global authoritative flag to handle requests by clients for
+        // unknown IP addresses (ignore if disabled, NAK if enabled).
+        "authoritative": false,
+
+        // Global bootfile name to be set in the 'file' field.
+        "boot-file-name": "/dev/null",
+
+        // Ordered list of client classes used by the DHCPv4 server.
+        "client-classes": [
+            {
+                // Class specific bootfile name to be set in the 'file' field.
+                "boot-file-name": "/tmp/bootfile.efi",
+
+                // Class name.
+                "name": "phones_server1",
+
+                // Class specific next server address to use in bootstrap, which
+                // is set in 'siaddr' field.
+                "next-server": "10.2.3.4",
+
+                // Class specific DHCPv4 options list.
+                "option-data": [],
+
+                // Class specific DHCPv4 option definitions, i.e. custom formats
+                // specified for non-standard options.
+                "option-def": [],
+
+                // Class specific optional server hostname, which is set in
+                // 'sname' field.
+                "server-hostname": "",
+
+                // Class selection expression. The DHCP packet is assigned to this
+                // class when the given expression evaluates to true.
+                "test": "member('HA_server1')",
+
+                // Class valid lifetime.
+                "valid-lifetime": 6000,
+
+                // Class min valid lifetime.
+                "min-valid-lifetime": 4000,
+
+                // Class max valid lifetime.
+                "max-valid-lifetime": 8000
+            },
+            {
+                // Default value of the class specific bootfile name. Empty name
+                // means that the bootfile name is unspecified.
+                "boot-file-name": "",
+
+                // Second class name.
+                "name": "phones_server2",
+
+                // Default value of the class specific next server address. The
+                // zero IPv4 address means that it is unspecified.
+                "next-server": "0.0.0.0",
+
+                // Class specific DHCPv4 options list.
+                "option-data": [],
+
+                // Class specific DHCPv4 option definitions, i.e. custom formats
+                // specified for non-standard options.
+                "option-def": [],
+
+                // Class specific optional server hostname, which is set in
+                // 'sname' field.
+                "server-hostname": "",
+
+                // Class selection expression. The DHCP packet is assigned to this
+                // class when the given expression evaluates to true.
+                "test": "member('HA_server2')"
+            },
+
+            {
+                // Third class name.
+                "name": "late",
+
+                // Boolean flag indicating that the class expression is only evaluated
+                // when the class is required, e.g. selected address pool configuration
+                // includes this class name in its "require-client-classes" list. The
+                // default value false means that the class test expression must
+                // always be evaluated.
+                "only-if-required": true,
+
+                // Class selection expression.
+                "test": "member('ALL')"
+            }
+        ],
+
+        // Parameters for triggering behaviors compatible with broken or
+        // non-compliant clients, relays or other agents
+        "compatibility": {
+            // Parse options more leniently where fields can be deduced
+            // deterministically even if against RFC or common practice.
+            "lenient-option-parsing": true
+        },
+
+        // Command control socket configuration parameters for Kea DHCPv4 server.
+        "control-socket": {
+            // Location of the unix domain socket file the DHCPv4 server uses
+            // to receive control commands from the Kea Control Agent or the
+            // local server administrator.
+            "socket-name": "/tmp/kea4-ctrl-socket",
+
+            // Control socket type used by the Kea DHCPv4 server. The 'unix'
+            // socket is currently the only supported type.
+            "socket-type": "unix"
+        },
+
+        // Specifies a prefix to be prepended to the generated Client FQDN.
+        // It may be specified at the global, shared-network and subnet levels.
+        "ddns-generated-prefix": "myhost",
+
+        // Boolean flag indicating that server should ignore DHCP client
+        // wishes to update DNS on its own. With that flag set to true
+        // the server will send DNS updates for both forward and
+        // reverse DNS data. The default value is false, which indicates
+        // that the server will delegate DNS update to the client when
+        // requested. It may be specified at the global, shared-network
+        // and subnet levels.
+        "ddns-override-client-update": false,
+
+        // Boolean flag indicating that the server should override DHCP
+        // client's wish to not update the DNS. With this parameter
+        // set to true the server will send DNS update even when
+        // the client requested no update.  It may be specified at the
+        // global, shared-network and subnet levels.
+        "ddns-override-no-update": false,
+
+        // Suffix appended to the partial name sent to the DNS. The
+        // default value is an empty string which indicates that no
+        // suffix is appended.  It may be specified at the global,
+        // shared-network and subnet levels.
+        "ddns-qualifying-suffix": "",
+
+        // Enumeration specifying whether the server should honor
+        // hostname or Client FQDN sent by the client or replace
+        // this name. The acceptable values are: "never" (use the
+        // name the client sent), "always" (replace the name the
+        // client sent), "when-present" (replace the name the client
+        // sent, but do not generate one when the client didn't sent
+        // the name), "when-not-present" (generate the name when
+        // client didn't send one, otherwise leave the name the
+        // client sent). The default value is "never".  It may be
+        // specified at the global, shared-network and subnet levels.
+        "ddns-replace-client-name": "never",
+
+        // Boolean flag which enables or disables the DDNS updating. It
+        // defaults to true.  It may be specified at the global, shared-
+        // network and subnet levels. It works in conjunction with
+        // dhcp-ddns:enable-updates which must be true to enable connectivity
+        // to kea-dhcp-ddns.
+        "ddns-send-updates": true,
+
+        // Boolean flag, which when true instructs the server to always
+        // update DNS when leases are renewed, even if the DNS information
+        // has not changed.  The server's default behavior (i.e. flag is false)
+        // is to only update DNS if the DNS information has changed.  It
+        // may be specified at the global, shared-network and subnet levels.
+        "ddns-update-on-renew": true,
+
+        // Boolean flag, which is passed to kea-dhcp-ddns with each DDNS
+        // update request to indicate whether or not DNS update conflict
+        // resolution as described in RFC 4703 should be employed for the
+        // given update request.  The default value for this flag is true.
+        // It may be specified at the global, shared-network and subnet levels.
+        "ddns-use-conflict-resolution": true,
+
+        // Time in seconds specifying how long a declined lease should be
+        // excluded from DHCP assignments. The default value is 24 hours.
+        "decline-probation-period": 86400,
+
+        // Name Change Requests forwarding configuration for Kea DHCPv4 server.
+        // NCRs are sent to Kea D2 module to update DNS upon allocation of the
+        // DHCP leases.
+        "dhcp-ddns": {
+            // Boolean flag indicating if Kea DHCPv4 server should connect to
+            // kea-dhcp-ddns.  This must be true for NCRs to be created and
+            // sent to kea-dhcp-ddns. By default NCRs are not generated.
+            "enable-updates": false,
+
+            // Specifies maximum number of NCRs to queue waiting to be sent
+            // to Kea D2 server.
+            "max-queue-size": 1024,
+
+            // Packet format to use when sending NCRs to Kea D2 server.
+            // Currently, only JSON format is supported.
+            "ncr-format": "JSON",
+
+            // Socket protocol to use when sending NCRs to D2. Currently,
+            // only UDP is supported.
+            "ncr-protocol": "UDP",
+
+            // IP address that Kea DHCPv4 server should use to send
+            // NCRs to D2. Default value of zero indicates that Kea
+            // should pick suitable address.
+            "sender-ip": "0.0.0.0",
+
+            // Port number that Kea DHCPv4 server should use to send
+            // NCRs to D2. Default value of zero indicates that Kea
+            // should pick suitable port.
+            "sender-port": 0,
+
+            // IP address on which D2 listens for NCRs.
+            "server-ip": "127.0.0.1",
+
+            // Port number on which D2 listens for NCRs.
+            "server-port": 53001,
+
+            // The follow parameters are DEPRECATED.  They have been
+            // replaced with parameters that may be set at the global,
+            // shared-network, and subnet4 scopes.  They are listed here
+            // as configuration parsing still accepts them.  Eventually
+            // support for them will be removed.
+            "generated-prefix": "myhost",
+            "hostname-char-replacement": "x",
+            "hostname-char-set": "[^A-Za-z0-9.-]",
+            "override-client-update": false,
+            "override-no-update": false,
+            "qualifying-suffix": "",
+            "replace-client-name": "never"
+        },
+
+        // Specifies the first of the two consecutive ports of the UDP
+        // sockets used for communication between DHCPv6 and DHCPv4
+        // servers. See RFC 7341.
+        "dhcp4o6-port": 6767,
+
+        // Boolean flag indicating whether or not the Kea DHCPv4 server
+        // should send back Client Identifier option in its responses.
+        // The default value is true which indicates that the option
+        // must be sent back if the client included it. The false
+        // value instructs the server to not send this option for
+        // backward compatibility with older DHCP specifications which
+        // stated that Client Identifier must not be sent back.
+        "echo-client-id": true,
+
+        // Collection of Kea DHCPv4 server parameters configuring how
+        // the server should process expired DHCP leases.
+        "expired-leases-processing": {
+            // Specifies the number of seconds since last removal of
+            // the expired leases when next removal should occur.
+            "flush-reclaimed-timer-wait-time": 25,
+
+            // Specifies the time period in seconds to keep expired
+            // leases in the lease database (lease affinity).
+            "hold-reclaimed-time": 3600,
+
+            // Specifies the maximum number of expired leases that can be
+            // processed in a single attempt to clean up the lease
+            // database from the expired leases. If there are more
+            // expired leases, they will be processed during the next
+            // cleanup attempt.
+            "max-reclaim-leases": 100,
+
+            // Specifies the maximum time in milliseconds that the single
+            // attempt to cleanup the lease database from the expired
+            // leases may take.
+            "max-reclaim-time": 250,
+
+            // Specifies the time period in seconds since last attempt
+            // to process expired leases to initiate the next attempt.
+            "reclaim-timer-wait-time": 10,
+
+            // Specifies the maximum number of expired leases processing
+            // cycles which didn't result in full cleanup of the lease
+            // database from the expired leases, after which a
+            // warning message is issued.
+            "unwarned-reclaim-cycles": 5
+        },
+
+        // List of hooks libraries and their specific configuration parameters
+        // to be loaded by Kea DHCPv4 server.
+        "hooks-libraries": [
+            {
+                // Location of the hooks library to be loaded.
+                "library": "/opt/lib/kea/hooks/libdhcp_lease_cmds.so",
+
+                // Hook library specific configuration parameters.
+                "parameters": { }
+            }
+        ],
+
+        // List of access credentials to external sources of IPv4 reservations,
+        "hosts-databases": [
+            {
+                // Name of the database to connect to.
+                "name": "keatest",
+
+                // Host on which the database resides.
+                "host": "localhost",
+
+                // Database password.
+                "password": "keatest",
+
+                // Port on which the database is available.
+                "port": 3306,
+
+                // Type of the database, e.g. "mysql", "postgresql".
+                "type": "mysql",
+
+                // User name to be used to access the database.
+                "user": "keatest",
+
+                // Read only mode.
+                "readonly": false,
+
+                // Next entries are for the OpenSSL support in MySQL.
+
+                // Trust anchor aka certificate authority file or directory.
+                "trust-anchor": "my-ca",
+
+                // Client certificate file name.
+                "cert-file": "my-cert",
+
+                // Private key file name.
+                "key-file": "my-key",
+
+                // Cipher list (see the OpenSSL ciphers command manual).
+                "cipher-list": "AES"
+            },
+            {
+                // Name of the database to connect to.
+                "name": "keatest",
+
+                // Host on which the database resides.
+                "host": "localhost",
+
+                // Database password.
+                "password": "keatest",
+
+                // Port on which the database is available.
+                "port": 5432,
+
+                // Type of the database, e.g. "mysql", "postgresql".
+                "type": "postgresql",
+
+                // User name to be used to access the database.
+                "user": "keatest"
+            },
+            {
+                // Name of the database to connect to.
+                "name": "keatest",
+
+                // Database password.
+                "password": "keatest",
+
+                // Port on which the database is available.
+                "port": 9042,
+
+                // Type of the database, e.g. "mysql", "postgresql".
+                "type": "mysql",
+
+                // User name to be used to access the database.
+                "user": "keatest",
+
+                // Connection reconnect wait time.
+                // This parameter governs how long Kea waits before attempting
+                // to reconnect. Expressed in milliseconds. The default is 0
+                // (disabled) for MySQL and PostgreSQL.
+                "reconnect-wait-time": 3000,
+
+                // Connection maximum reconnect tries.
+                "max-reconnect-tries": 3,
+
+                // Action to take when connection recovery fails.
+                // Supported values: stop-retry-exit, serve-retry-exit,
+                // serve-retry-continue
+                "on-fail": "stop-retry-exit",
+
+                // Connection connect timeout.
+                "connect-timeout": 100
+            }
+        ],
+
+        // List of host reservation identifier types to be used by the
+        // Kea DHCPv4 server to fetch static reservations for the
+        // DHCP clients. All identifiers are used by default, which
+        // means that the server will issue multiple queries to the
+        // database to find if there is a reservation for the particular
+        // client. If the particular deployment uses only subset, e.g.
+        // one, identifier type, this identifier should be only listed
+        // here to prevent unnecessary queries to the database.
+        "host-reservation-identifiers": [
+            "hw-address",
+            "duid",
+            "circuit-id",
+            "client-id",
+            "flex-id"
+        ],
+
+        // Specifies configuration of interfaces on which the Kea DHCPv4
+        // server is listening to the DHCP queries.
+        "interfaces-config": {
+            // Specifies whether the server should use "udp" socket or
+            // "raw" sockets to listen to the DHCP traffic. The "raw"
+            // sockets are useful when direct DHCP traffic is being
+            // received.
+            "dhcp-socket-type": "udp",
+
+            // Specifies a list of interfaces on which the Kea DHCPv4
+            // server should listen to the DHCP requests.
+            "interfaces": [
+                "eth0"
+            ],
+
+            // Enumeration which indicates what interface should be used
+            // to send DHCP response to the client. The default value is
+            // "same-as-inbound" which indicates that the response should
+            // be sent via the interface on which the client's query
+            // was received. The "use-routing" value indicates that the
+            // Kea server should use kernel's routing table to find the
+            // suitable interface.
+            "outbound-interface": "same-as-inbound",
+
+            // Boolean flag indicating if the available interfaces should
+            // be re-detected upon server reconfiguration. The default value
+            // is true which means that the interfaces are always
+            // re-detected.
+            "re-detect": true,
+
+            // Kea tries to bind the service sockets during initialization. It may
+            // fail due to a port being already opened or misconfiguration. Kea can
+            // suppress these errors and only logs them. This flag prevents starting
+            // the DHCP server without binding all sockets. If unspecified, it
+            // defaults to false.
+            "service-sockets-require-all": true,
+
+            // Kea tries to bind the service sockets during initialization. This
+            // option specifies how many times binding to interface will be retried.
+            // The default value is 0 which means that the operation will not be
+            // repeated.
+            "service-sockets-max-retries": 5,
+
+            // The time interval in milliseconds to wait before the next attempt to
+            // retry opening a service socket.
+            "service-sockets-retry-wait-time": 5000
+        },
+
+        // Boolean parameter which controls whether an early global host
+        // reservations lookup should be performed. This lookup takes place
+        // before subnet selection and when a global reservation is found
+        // with some client classes, it triggers a second phase classification.
+        // It can also be used to drop queries using host reservations as a
+        // decision table indexed by reservation identifiers.
+        "early-global-reservations-lookup": true,
+
+        // Boolean parameter which controls DHCP server's behavior with respect
+        // to creating host reservations for the same IP address. By default
+        // this flag is set to true in which case the server prevents creation
+        // of multiple host reservations for the same IP address. When this
+        // parameter is set to false, the server allows for creating multiple
+        // reservations for the same IP address within a subnet. This setting
+        // is useful in deployments in which a given host may be communicating
+        // with a DHCP server over multiple interfaces and depending on the
+        // chosen interface different MAC address (or other identifier) will
+        // be used to identify the host. Note that some host backends do not
+        // support the mode in which multiple reservations for the same IP
+        // address are used. If these backends are in use and this setting
+        // is attempted a configuration error will occur. The MySQL and
+        // PostgreSQL backends do support this mode.
+        "ip-reservations-unique": true,
+
+        /// Boolean parameter which controls whether host reservations lookup
+        /// should be performed before lease lookup. This parameter has effect
+        /// only when multi-threading is disabled. When multi-threading is
+        /// enabled, host reservations lookup is always performed first to avoid
+        /// lease lookup resource locking.
+        "reservations-lookup-first": true,
+
+        // Specifies credentials to access lease database.
+        "lease-database": {
+            // memfile backend specific parameter specifying the interval
+            // in seconds at which lease file should be cleaned up (outdated
+            // lease entries are removed to prevent lease file from growing
+            // infinitely).
+            "lfc-interval": 3600,
+
+            // Maximum number of lease file read errors allowed before
+            // loading the file is abandoned.  Defaults to 0 (no limit).
+            "max-row-errors": 100,
+
+            // Name of the lease file. In case of database it specifies the
+            // database name.
+            "name": "/tmp/kea-dhcp4.csv",
+
+            // memfile specific parameter indicating whether leases should
+            // be saved on persistent storage (disk) or not. The true value
+            // is the default and it indicates that leases are stored in the
+            // persistent storage. This setting must be used in production.
+            // The false value should only be used for testing purposes
+            // because non stored leases will be lost upon Kea server restart.
+            "persist": true,
+
+            // Lease database backend type, i.e. "memfile", "mysql" or
+            // "postgresql".
+            "type": "memfile"
+        },
+
+        // Boolean value indicating if the Kea DHCPv4 server should use client
+        // identifier value sent by the client or ignore it. The default value
+        // is true which indicate that the server should use client identifier
+        // and that it takes precedence over client's MAC address. In deployments
+        // where MAC address should take precedence this value can be set to
+        // false, in which case the clients will be identified by MAC address.
+        // This is specifically useful when clients don't generate unique
+        // identifiers or these identifiers are not stable etc.
+        "match-client-id": false,
+
+        // Global value of the next server address set in 'siaddr' field.
+        // The global value may be overridden in lower level configuration
+        // scopes.
+        "next-server": "192.0.2.123",
+
+        // Global value which limits the number of client packets (e.g.
+        // DHCPREQUESTs) that may be parked while waiting for hook library
+        // work to complete, prior to a response (e.g. DHCPACK) being sent
+        // back to the client.  A typical example is when kea-dhcp4 parks a
+        // DHCPREQUEST while it sends the lease update(s) to its HA peer(s).
+        // The packet is unparked once the update(s) have been acknowledged.
+        // This value limits the number of packets that can be held pending
+        // the updates. In times of heavy client traffic, this value can keep
+        // kea-dhcp4 from building an insurmountable backlog of updates.
+        "parked-packet-limit": 128,
+
+        // List of global DHCP options that Kea DHCPv4 server assigns to the
+        // clients.
+        "option-data": [
+            {
+                // Boolean flag indicating if the given option is always
+                // send in response or only when requested. The default
+                // value of false indicates that it is only sent when
+                // requested.
+                "always-send": false,
+
+                // Option code. It is not required if the option name is
+                // provided.
+                "code": 6,
+
+                // Boolean value indicating whether the option data specified
+                // in the "data" field is specified as a string of hexadecimal
+                // digits or in human readable CSV format.
+                "csv-format": true,
+
+                // Option data to be stored in the option payload.
+                "data": "192.0.3.1, 192.0.3.2",
+
+                // Option name. It is not required of the option code is
+                // provided.
+                "name": "domain-name-servers",
+
+                // Option space. The default is the "dhcp4" option space which
+                // groups top level DHCPv4 options.
+                "space": "dhcp4"
+            }
+        ],
+
+        // List of global option definitions, i.e. option formats, that the
+        // Kea DHCPv4 server is using.
+        "option-def": [
+            {
+                // Boolean flag indicating if the option definition comprises
+                // an array of values of some type, e.g. array of IPv4 addresses.
+                // The default value of false means that the option does not
+                // comprise an array of values.
+                "array": false,
+
+                // Option code.
+                "code": 6,
+
+                // Holds a name of the option space encapsulated by this option.
+                // All options that belong to this option space will be sent
+                // as sub-options of this option. Empty string means that this
+                // option doesn't encapsulate any option.
+                "encapsulate": "",
+
+                // Option name.
+                "name": "my-option",
+
+                // Specifies the types of fields within the option if the option
+                // is said to be a "record" (see "type"). in this particular example
+                // this option comprises two fields, 1 byte and 2 bytes long.
+                "record-types": "uint8, uint16",
+
+                // Name of the option space to which this option belongs.
+                "space": "my-space",
+
+                // Option type. All possible types are listed in the Kea
+                // Administrator Reference Manual.
+                "type": "record"
+            }
+        ],
+
+        // Global value for the rebind timer, i.e. the time after which the
+        // DHCP client enters rebind state if it fails to renew the lease.
+        "rebind-timer": 40,
+
+        // Global value for the renew timer, i.e. the timer after which the
+        // DHCP client renews the lease.
+        "renew-timer": 30,
+
+        // Global value to store extended information (e.g. relay agent
+        // information) with each lease.
+        "store-extended-info": true,
+
+        // Statistics keep some samples per observation point.
+        // There are two default values: maximum count and maximum age.
+        // Set the maximum count to zero disables it.
+        "statistic-default-sample-count": 0,
+
+        // When the maximum count is 0 the maximum age (in seconds) applies.
+        "statistic-default-sample-age": 60,
+
+        // Multi-threading parameters.
+        "multi-threading": {
+            // By default Kea processes packets on a single thread (default
+            // 'false' value for this option). To enable multi-threading, this
+            // option can be set ('true' value).
+            "enable-multi-threading": false,
+
+            // When multi-threading is enabled, Kea will process packets on a
+            // number of multiple threads configurable through this option. The
+            // value must be a positive integer (0 means auto detect).
+            "thread-pool-size": 0,
+
+            // When multi-threading is enabled, Kea will read packets from the
+            // interface and append a working item to the thread pool. This
+            // option configures the maximum number of items that can be queued.
+            // The value must be a positive integer (0 means unlimited).
+            "packet-queue-size": 0
+        },
+
+        // Governs how the Kea DHCPv4 server should deal with the invalid
+        // data received from the client.
+        "sanity-checks": {
+            // Specifies how the Kea DHCPv4 server should behave when invalid
+            // data is read for a lease from the lease file. The following
+            // values are supported "none" (don't attempt to correct the
+            // lease information), "warn" (print a warning for subnet-id
+            // related inconsistencies), "fix" (correct the subnet id by
+            // trying to find the suitable subnet), "fix-del" (similar
+            // to "fix" but delete the lease if no suitable subnet found),
+            // "del" (delete the lease if the lease has invalid subnet
+            // identifier value).
+            "lease-checks": "warn"
+        },
+
+        // List of shared networks used by Kea DHCPv4 server. The shared
+        // networks group subnets together.
+        "shared-networks": [
+            {
+                // Shared network level authoritative flag.
+                "authoritative": false,
+
+                // Shared network level bootfile name.
+                "boot-file-name": "/dev/null",
+
+                // Restricts this shared network to allow only clients
+                // that belong to the particular client class. If an
+                // empty string is provided, no restriction is applied.
+                "client-class": "",
+
+                // Shared network level value. See description at the global level.
+                "ddns-generated-prefix": "myhost",
+
+                // Shared network level value. See description at the global level.
+                "ddns-override-client-update": false,
+
+                // Shared network level value. See description at the global level.
+                "ddns-override-no-update": false,
+
+                // Shared network level value. See description at the global level.
+                "ddns-qualifying-suffix": "",
+
+                // Shared network level value. See description at the global level.
+                "ddns-replace-client-name": "never",
+
+                // Shared network level value. See description at the global level.
+                "ddns-send-updates": true,
+
+                // Shared network level value. See description at the global level.
+                "ddns-update-on-renew": true,
+
+                // Shared network level value. See description at the global level.
+                "ddns-use-conflict-resolution": true,
+
+                // Shared network level value. See description at the global level.
+                "hostname-char-replacement": "x",
+
+                // Shared network level value. See description at the global level.
+                "hostname-char-set": "[^A-Za-z0-9.-]",
+
+                // Specifies that this shared network is selected for the
+                // requests received on the particular interface.
+                "interface": "eth0",
+
+                // Shared network level flag specifying whether the client
+                // identifier should be used for identifying clients.
+                "match-client-id": true,
+
+                // Shared network name.
+                "name": "my-secret-network",
+
+                // Shared network level specification of the next server
+                // to be sent in 'siaddr'.
+                "next-server": "192.0.2.123",
+
+                // List of shared network specific DHCP options.
+                "option-data": [],
+
+                // List of IPv4 relay addresses for which this shared
+                // network is selected.
+                "relay": {
+                    "ip-addresses": []
+                },
+
+                // Shared network level rebind timer.
+                "rebind-timer": 41,
+
+                // Shared network level renew timer.
+                "renew-timer": 31,
+
+                // Shared network level compute T1 and T2 timers.
+                "calculate-tee-times": true,
+
+                // T1 = valid lifetime * .5.
+                "t1-percent": .5,
+
+                // T2 = valid lifetime * .75.
+                "t2-percent": .75,
+
+                // Cache threshold = valid lifetime * .25.
+                "cache-threshold": .25,
+
+                // Cache maximum: when the client last transmission time
+                // is close enough the lease is not renewed and current
+                // lease is returned as it was "cached".
+                "cache-max-age": 1000,
+
+                // Enumeration specifying server's mode of operation when it
+                // fetches host reservations.
+                // "reservation-mode": "all",
+                // It is replaced by the "reservations-global",
+                // "reservations-in-subnet" and "reservations-out-of-pool"
+                // parameters.
+
+                // Specify if server should lookup global reservations.
+                "reservations-global": false,
+
+                // Specify if server should lookup in-subnet reservations.
+                "reservations-in-subnet": true,
+
+                // Specify if server can assume that all reserved addresses
+                // are out-of-pool.
+                // Ignored when reservations-in-subnet is false.
+                // If specified, it is inherited by "subnet4" levels.
+                "reservations-out-of-pool": false,
+
+                // List of client classes which must be evaluated when this shared
+                // network is selected for client assignments.
+                "require-client-classes": [ "late" ],
+
+                // Turn off storage of extended information (e.g. relay agent
+                // information) with each lease for this shared-network.
+                "store-extended-info": false,
+
+                // Shared network level server hostname set in 'sname' field.
+                "server-hostname": "",
+
+                // List of IPv4 subnets belonging to this shared network.
+                "subnet4": [
+                    {
+                        // Interface name matched against inbound interface name.
+                        // Used in DHCPv4o6. See RFC 7341.
+                        "4o6-interface": "",
+
+                        // Interface ID option value. See RFC 7341.
+                        "4o6-interface-id": "",
+
+                        // Prefix matched against source address. See RFC7341.
+                        "4o6-subnet": "2001:db8:1:1::/64",
+
+                        // Subnet level authoritative flag.
+                        "authoritative": false,
+
+                        // Subnet level bootfile name, set in 'file' field.
+                        "boot-file-name": "",
+
+                        // Restricts this subnet to allow only clients that belong
+                        // to the particular client class. If an empty string is
+                        // provided, no restriction is applied.
+                        "client-class": "",
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-generated-prefix": "myhost",
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-override-client-update": false,
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-override-no-update": false,
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-qualifying-suffix": "",
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-replace-client-name": "never",
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-send-updates": true,
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-update-on-renew": true,
+
+                        // Subnet level value. See description at the global level.
+                        "ddns-use-conflict-resolution": true,
+
+                        // Subnet level value. See description at the global level.
+                        "hostname-char-replacement": "x",
+
+                        // Subnet level value. See description at the global level.
+                        "hostname-char-set": "[^A-Za-z0-9.-]",
+
+                        // Subnet unique identifier.
+                        "id": 1,
+
+                        // Specifies that this subnet is selected for the requests
+                        // received on the particular interface.
+                        "interface": "eth0",
+
+                        // Subnet level flag specifying whether the client identifier
+                        // should be used for identifying clients.
+                        "match-client-id": true,
+
+                        // Subnet level specification of the next server to be sent
+                        // in 'siaddr'.
+                        "next-server": "0.0.0.0",
+
+                        // Turn on storage of extended information (e.g. relay agent
+                        // information) with each lease for this subnet.
+                        "store-extended-info": true,
+
+                        // Subnet level list of DHCP options.
+                        "option-data": [
+                            {
+                                // Boolean flag indicating if the particular option
+                                // should be always sent or sent only when requested.
+                                "always-send": false,
+
+                                // Option code.
+                                "code": 3,
+
+                                // Boolean flag indicating if the option value specified
+                                // in "data" is a string of hexadecimal values or human
+                                // readable CSV value.
+                                "csv-format": true,
+
+                                // Option data to be included in the option payload.
+                                "data": "192.0.3.1",
+
+                                // Option name.
+                                "name": "routers",
+
+                                // Option space. The default value "dhcp4" designates the
+                                // top level option space.
+                                "space": "dhcp4"
+                            }
+                        ],
+
+                        // List of IP address pools belonging to the subnet.
+                        "pools": [
+                            {
+                                // Restricts this pool to be only used for the client
+                                // requests belonging to a particular client class.
+                                "client-class": "phones_server1",
+
+                                // Pool level list of DHCP options.
+                                "option-data": [],
+
+                                // Address range used for client assignments.
+                                "pool": "192.1.0.1 - 192.1.0.200",
+
+                                // List of client classes which must be evaluated when this pool
+                                // is selected for client assignments.
+                                "require-client-classes": [ "late" ]
+                            },
+                            {
+                                // Restricts this pool to be only used for the client
+                                // requests belonging to a particular client class.
+                                "client-class": "phones_server2",
+
+                                // Pool level list of DHCP options.
+                                "option-data": [],
+
+                                // Address range used for client assignments.
+                                "pool": "192.3.0.1 - 192.3.0.200",
+
+                                // List of client classes which must be evaluated when this pool
+                                // is selected for client assignments.
+                                "require-client-classes": []
+                            }
+                        ],
+
+                        // Subnet level value of the rebind timer.
+                        "rebind-timer": 40,
+
+                        // List of IPv4 relay addresses for which this subnet is
+                        // selected.
+                        "relay": {
+                            "ip-addresses": [
+                                "192.168.56.1"
+                            ]
+                        },
+
+                        // Subnet level value of the renew timer.
+                        "renew-timer": 30,
+
+                        // Enumeration specifying server's mode of operation when it
+                        // fetches host reservations.
+                        // "reservation-mode": "all",
+                        // It is replaced by the "reservations-global",
+                        // "reservations-in-subnet" and
+                        // "reservations-out-of-pool" parameters.
+
+                        // Specify if server should lookup global reservations.
+                        "reservations-global": false,
+
+                        // Specify if server should lookup in-subnet reservations.
+                        "reservations-in-subnet": true,
+
+                        // Specify if server can assume that all reserved
+                        // addresses are out-of-pool.
+                        // Ignored when reservations-in-subnet is false.
+                        "reservations-out-of-pool": false,
+
+                        // Subnet level compute T1 and T2 timers.
+                        "calculate-tee-times": true,
+
+                        // T1 = valid lifetime * .5.
+                        "t1-percent": .5,
+
+                        // T2 = valid lifetime * .75.
+                        "t2-percent": .75,
+
+                        // Cache threshold = valid lifetime * .25.
+                        "cache-threshold": .25,
+
+                        // Subnet-level cache maximum.
+                        "cache-max-age": 1000,
+
+                        // List of static IPv4 reservations assigned to the clients belonging
+                        // to this subnet. For detailed example see reservations.json.
+                        "reservations": [
+                            {
+                                // Identifier used for client matching. Supported values are
+                                // "hw-address", "client-id", "duid", "circuit-id", "flex-id".
+                                "circuit-id": "01:11:22:33:44:55:66",
+
+                                // Reserved IP address.
+                                "ip-address": "192.0.2.204",
+
+                                // Hostname.
+                                "hostname": "foo.example.org",
+
+                                // Reservation specific option data.
+                                "option-data": [
+                                    {
+                                        // Option name.
+                                        "name": "vivso-suboptions",
+
+                                        // Option data.
+                                        "data": "4491"
+                                    }
+                                ]
+                            }
+                        ],
+
+                        // List of client classes which must be evaluated when this subnet
+                        // is selected for client assignments.
+                        "require-client-classes": [ "late" ],
+
+                        // Subnet level server hostname set in 'sname' field.
+                        "server-hostname": "",
+
+                        // Subnet prefix.
+                        "subnet": "192.0.0.0/8",
+
+                        // Subnet level (default) valid lifetime.
+                        "valid-lifetime": 6000,
+
+                        // Subnet level min valid lifetime.
+                        "min-valid-lifetime": 4000,
+
+                        // Subnet level max valid lifetime.
+                        "max-valid-lifetime": 8000
+                    }
+                ],
+
+                // Shared network level (default) valid lifetime.
+                "valid-lifetime": 6001,
+
+                // Subnet level min valid lifetime.
+                "min-valid-lifetime": 4001,
+
+                // Subnet level max valid lifetime.
+                "max-valid-lifetime": 8001
+            }
+        ],
+
+        // Global server hostname set in the 'sname' field.
+        "server-hostname": "",
+
+        // List of IPv4 subnets which don't belong to any shared network.
+        "subnet4": [],
+
+        // Global valid (default) lifetime value.
+        "valid-lifetime": 6000,
+
+        // Global min valid lifetime value.
+        "min-valid-lifetime": 4000,
+
+        // Global max valid lifetime value.
+        "max-valid-lifetime": 8000,
+
+        // Reservations (examples are in other files).
+        "reservations": [],
+
+        // Configuration control (currently not used, i.e. this syntax
+        // is already defined but corresponding feature is not implemented).
+        "config-control": {
+            // Only configuration databases entry is defined.
+            "config-databases": [
+                {
+                    // Name of the database to connect to.
+                    "name": "config",
+
+                    // Type of the database, e.g. "mysql", "postgresql".
+                    "type": "mysql"
+                }
+            ],
+            // Intervals between attempts to fetch configuration updates
+            // via the configuration backends used.
+            "config-fetch-wait-time": 30
+        },
+
+        // Server tag.
+        "server-tag": "my DHCPv4 server",
+
+        // DHCP queue control parameters.
+        "dhcp-queue-control": {
+            // Enable queue is mandatory.
+            "enable-queue": true,
+
+            // Queue type was mandatory.
+            "queue-type": "kea-ring4",
+
+            // Capacity is optional.
+            "capacity": 64
+        },
+
+        // Fetches host reservations.
+        // "reservation-mode": "all",
+        // It is replaced by the "reservations-global",
+        // "reservations-in-subnet" and "reservations-out-of-pool" parameters.
+
+        // Specify if server should lookup global reservations.
+        "reservations-global": false,
+
+        // Specify if server should lookup in-subnet reservations.
+        "reservations-in-subnet": true,
+
+        // Specify if 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,
+
+        // Global compute T1 and T2 timers.
+        "calculate-tee-times": true,
+
+        // T1 = valid lifetime * .5.
+        "t1-percent": .5,
+
+        // T2 = valid lifetime * .75.
+        "t2-percent": .75,
+
+        // Cache threshold = valid lifetime * .25.
+        "cache-threshold": .25,
+
+        // Global cache maximum.
+        "cache-max-age": 1000,
+
+        // String of zero or more characters with which to replace each
+        // invalid character in the hostname or Client FQDN. The default
+        // value is an empty string which will cause invalid characters
+        // to be omitted rather than replaced.
+        "hostname-char-replacement": "x",
+
+        // Regular expression describing the invalid character set in
+        // the hostname or Client FQDN.
+        "hostname-char-set": "[^A-Za-z0-9.-]",
+
+        // List of loggers used by the servers using this configuration file.
+        "loggers": [
+            {
+                // Debug level, a value between 0..99. The greater the value
+                // the more detailed debug log.
+                "debuglevel": 99,
+
+                // Name of the logger.
+                "name": "kea-dhcp4",
+
+                // Configures how the log should be output.
+                "output_options": [
+                    {
+                        // Determines whether the log should flushed to a file.
+                        "flush": true,
+
+                        // Specifies maximum filesize before the file is being rotated.
+                        "maxsize": 10240000,
+
+                        // Specifies the maximum number of rotated files being kept.
+                        "maxver": 1,
+
+                        // Specifies logging destination.
+                        "output": "stdout",
+
+                        // Specifies log entry content
+                        "pattern": "%D{%Y-%m-%d %H:%M:%S.%q} %-5p [%c/%i] %m\n"
+                    }
+                ],
+
+                // Specifies logging severity, i.e. "ERROR", "WARN", "INFO", "DEBUG".
+                "severity": "INFO"
+            }
+        ],
+
+        // Look at advanced example for the use of user-contexts.
+        "user-context": { }
+    }
+}