Provided by: knot_2.7.6-2_amd64 bug

NAME

       knot.conf - Knot DNS configuration file

DESCRIPTION

       Configuration files for Knot DNS use simplified YAML format. Simplified means that not all
       of the features are supported.

       For the description of configuration items, we have to declare a meaning of the  following
       symbols:

       · INT – Integer

       · STR – Textual string

       · HEXSTR – Hexadecimal string (with 0x prefix)

       · BOOL – Boolean value (on/off or true/false)

       · TIME  –  Number  of seconds, an integer with possible time multiplier suffix (s ~ 1, m ~
         60, h ~ 3600 or d ~ 24 * 3600)

       · SIZE – Number of bytes, an integer with possible size multiplier suffix  (B  ~  1,  K  ~
         1024, M ~ 1024^2 or G ~ 1024^3)

       · BASE64 – Base64 encoded string

       · ADDR – IPv4 or IPv6 address

       · DNAME – Domain name

       · ... – Multi-valued item, order of the values is preserved

       · [ ] – Optional value

       · | – Choice

       There  are  12  main sections (module, server, control, log, statistics, keystore, policy,
       key, acl, remote, template, and zone) and module sections with the mod- prefix.   Most  of
       the sections (excluding server, control, and statistics) are sequences of settings blocks.
       Each settings block begins with a unique identifier, which can be used as a reference from
       other sections (such identifier must be defined in advance).

       A multi-valued item can be specified either as a YAML sequence:

          address: [10.0.0.1, 10.0.0.2]

       or as more single-valued items each on an extra line:

          address: 10.0.0.1
          address: 10.0.0.2

       If  an  item value contains spaces or other special characters, it is necessary to enclose
       such value within double quotes " ".

COMMENTS

       A comment begins with  a  #  character  and  is  ignored  during  processing.   Also  each
       configuration  section or sequence block allows a permanent comment using the comment item
       which is stored in the server beside the configuration.

INCLUDES

       Another configuration file or files, matching a pattern, can be included at the top  level
       in  the current file. If the path is not absolute, then it is considered to be relative to
       the current file. The pattern can be an arbitrary string meeting POSIX glob  requirements,
       e.g. dir/*.conf.  Matching files are processed in sorted order.

          include: STR

MODULE SECTION

       Dynamic modules loading configuration.

       NOTE:
          If  configured  with non-empty `--with-moduledir=path` parameter, all shared modules in
          this directory will be automatically loaded.

          module:
            - id: STR
              file: STR

   id
       A module identifier in the form of the mod- prefix and module name suffix.

   file
       A path to a shared library file with the module implementation.

       Default: ${libdir}/knot/modules-${version}/module_name.so  (or  ${path}/module_name.so  if
       configured with --with-moduledir=path)

       WARNING:
          If  the path is not absolute, the library is searched in the set of system directories.
          See man dlopen for more details.

SERVER SECTION

       General options related to the server.

          server:
              identity: [STR]
              version: [STR]
              nsid: [STR|HEXSTR]
              rundir: STR
              user: STR[:STR]
              pidfile: STR
              udp-workers: INT
              tcp-workers: INT
              background-workers: INT
              async-start: BOOL
              tcp-handshake-timeout: TIME
              tcp-idle-timeout: TIME
              tcp-reply-timeout: TIME
              max-tcp-clients: INT
              max-udp-payload: SIZE
              max-ipv4-udp-payload: SIZE
              max-ipv6-udp-payload: SIZE
              edns-client-subnet: BOOL
              answer-rotation: BOOL
              listen: ADDR[@INT] ...

   identity
       An identity of the server returned in the response to the query for TXT record  id.server.
       or hostname.bind. in the CHAOS class (RFC 4892).  Set empty value to disable.

       Default: FQDN hostname

   version
       A  version  of  the  server  software returned in the response to the query for TXT record
       version.server. or version.bind. in the  CHAOS  class  (RFC  4892).  Set  empty  value  to
       disable.

       Default: server version

   nsid
       A DNS name server identifier (RFC 5001). Set empty value to disable.

       Default: FQDN hostname

   rundir
       A path for storing run-time data (PID file, unix sockets, etc.).

       Default: ${localstatedir}/run/knot (configured with --with-rundir=path)

   user
       A  system  user  with  an optional system group (user:group) under which the server is run
       after starting and binding to interfaces. Linux capabilities are employed if supported.

       Default: root:root

   pidfile
       A PID file location.

       Default: rundir/knot.pid

   udp-workers
       A number of UDP workers (threads) used to process incoming queries over UDP.

       Default: auto-estimated optimal value based on the number of online CPUs

   tcp-workers
       A number of TCP workers (threads) used to process incoming queries over TCP.

       Default: auto-estimated optimal value based on the number of online CPUs

   background-workers
       A number of workers (threads) used to execute background operations  (zone  loading,  zone
       updates, etc.).

       Default: auto-estimated optimal value based on the number of online CPUs

   async-start
       If  enabled,  server  doesn't  wait  for  the  zones  to  be  loaded and starts responding
       immediately with SERVFAIL answers until the zone loads.

       Default: off

   tcp-handshake-timeout
       Maximum time between newly accepted TCP connection and the first query.  This is useful to
       disconnect  inactive  connections  faster  than  connections  that already made at least 1
       meaningful query.

       Default: 5

   tcp-idle-timeout
       Maximum idle time between requests on a TCP connection. This also limits  receiving  of  a
       single query, each query must be received in this time limit.

       Default: 20

   tcp-reply-timeout
       Maximum  time to wait for an outgoing connection or for a reply to an issued request (SOA,
       NOTIFY, AXFR...).

       Default: 10

   max-tcp-clients
       A maximum number of TCP clients connected in parallel, set this below the file  descriptor
       limit to avoid resource exhaustion.

       Default: 100

   max-udp-payload
       Maximum EDNS0 UDP payload size default for both IPv4 and IPv6.

       Default: 4096

   max-ipv4-udp-payload
       Maximum EDNS0 UDP payload size for IPv4.

       Default: 4096

   max-ipv6-udp-payload
       Maximum EDNS0 UDP payload size for IPv6.

       Default: 4096

   edns-client-subnet
       Enable  or disable EDNS Client Subnet support. If enabled, responses to queries containing
       the EDNS Client Subnet option always contain a valid EDNS Client Subnet  option  according
       to RFC 7871.

       Default: off

   answer-rotation
       Enable  or  disable  sorted-rrset  rotation  in the answer section of normal replies.  The
       rotation shift is simply determined by a query ID.

       Default: off

   listen
       One or more IP addresses where the server listens for  incoming  queries.   Optional  port
       specification  (default  is  53)  can  be  appended to each address using @ separator. Use
       0.0.0.0 for all configured IPv4 addresses or :: for all configured IPv6 addresses.

       Default: not set

KEY SECTION

       Shared TSIG keys used to authenticate communication with the server.

          key:
            - id: DNAME
              algorithm: hmac-md5 | hmac-sha1 | hmac-sha224 | hmac-sha256 | hmac-sha384 | hmac-sha512
              secret: BASE64

   id
       A key name identifier.

       NOTE:
          This value MUST be exactly the same as the  name  of  the  TSIG  key  on  the  opposite
          master/slave server(s).

   algorithm
       A TSIG key algorithm. See TSIG Algorithm Numbers.

       Possible values:

       · hmac-md5

       · hmac-sha1

       · hmac-sha224

       · hmac-sha256

       · hmac-sha384

       · hmac-sha512

       Default: not set

   secret
       Shared key secret.

       Default: not set

ACL SECTION

       Access  control  list rule definitions. The ACLs are used to match incoming connections to
       allow or deny requested operation (zone transfer request, DDNS update, etc.).

          acl:
            - id: STR
              address: ADDR[/INT] | ADDR-ADDR ...
              key: key_id ...
              action: notify | transfer | update ...
              deny: BOOL

   id
       An ACL rule identifier.

   address
       An ordered list of IP addresses, network subnets, or network ranges. The query must  match
       one of them. Empty value means that address match is not required.

       Default: not set

   key
       An  ordered list of references to TSIG keys. The query must match one of them. Empty value
       means that transaction authentication is not used.

       Default: not set

   action
       An ordered list of allowed (or denied) actions.

       Possible values:

       · notify – Allow incoming notify.

       · transfer – Allow zone transfer.

       · update – Allow zone updates.

       Default: not set

   deny
       If enabled, instead of allowing, deny the specified action, address, key,  or  combination
       if these items. If no action is specified, deny all actions.

       Default: off

CONTROL SECTION

       Configuration of the server control interface.

          control:
              listen: STR
              timeout: TIME

   listen
       A UNIX socket path where the server listens for control commands.

       Default: rundir/knot.sock

   timeout
       Maximum time the control socket operations can take. Set 0 for infinity.

       Default: 5

STATISTICS SECTION

       Periodic server statistics dumping.

          statistics:
              timer: TIME
              file: STR
              append: BOOL

   timer
       A period after which all available statistics metrics will by written to the file.

       Default: not set

   file
       A file path of statistics output in the YAML format.

       Default: rundir/stats.yaml

   append
       If enabled, the output will be appended to the file instead of file replacement.

       Default: off

KEYSTORE SECTION

       DNSSEC keystore configuration.

          keystore:
            - id: STR
              backend: pem | pkcs11
              config: STR

   id
       A keystore identifier.

   backend
       A key storage backend type.

       Possible values:

       · pem – PEM files.

       · pkcs11 – PKCS #11 storage.

       Default: pem

   config
       A backend specific configuration. A directory with PEM files (the path can be specified as
       a relative path to kasp-db) or a configuration string for PKCS #11  storage  (<pkcs11-url>
       <module-path>).

       NOTE:
          Example configuration string for PKCS #11:

              "pkcs11:token=knot;pin-value=1234 /usr/lib64/pkcs11/libsofthsm2.so"

       Default: kasp-db/keys

SUBMISSION SECTION

       Parameters of KSK submission checks.

          submission:
            - id: STR
              parent: remote_id ...
              check-interval: TIME
              timeout: TIME

   id
       A submission identifier.

   parent
       A  list  of references to parent's DNS servers to be checked for presence of corresponding
       DS records in the case of KSK submission. All of them must have a corresponding DS for the
       rollover to continue. If none is specified, the rollover must be pushed forward manually.

       Default: not set

       TIP:
          A DNSSEC-validating resolver can be set as a parent.

   check-interval
       Interval  for  periodic  checks of DS presence on parent's DNS servers, in the case of the
       KSK submission.

       Default: 1 hour

   timeout
       After this period, the KSK submission is automatically considered successful, even if  all
       the checks were negative or no parents are configured. Set 0 for infinity.

       Default: 0

POLICY SECTION

       DNSSEC policy configuration.

          policy:
            - id: STR
              keystore: STR
              manual: BOOL
              single-type-signing: BOOL
              algorithm: rsasha1 | rsasha1-nsec3-sha1 | rsasha256 | rsasha512 | ecdsap256sha256 | ecdsap384sha384 | ed25519
              ksk-size: SIZE
              zsk-size: SIZE
              ksk-shared: BOOL
              dnskey-ttl: TIME
              zsk-lifetime: TIME
              ksk-lifetime: TIME
              propagation-delay: TIME
              rrsig-lifetime: TIME
              rrsig-refresh: TIME
              nsec3: BOOL
              nsec3-iterations: INT
              nsec3-opt-out: BOOL
              nsec3-salt-length: INT
              nsec3-salt-lifetime: TIME
              ksk-submission: submission_id
              cds-cdnskey-publish: none | delete-dnssec | rollover | always

   id
       A policy identifier.

   keystore
       A  reference to a keystore holding private key material for zones. A special default value
       can be used for the default keystore settings.

       Default: default

   manual
       If enabled, automatic key management is not used.

       Default: off

   single-type-signing
       If enabled, Single-Type Signing Scheme is used in the automatic key management mode.

       Default: off

   algorithm
       An algorithm of signing keys and issued signatures. See DNSSEC Algorithm Numbers.

       Possible values:

       · rsasha1

       · rsasha1-nsec3-sha1

       · rsasha256

       · rsasha512

       · ecdsap256sha256

       · ecdsap384sha384

       · ed25519

       Default: ecdsap256sha256

       NOTE:
          Ed25519 algorithm is only available when compiled with GnuTLS 3.6.0+.

   ksk-size
       A length of newly generated KSK or CSK keys.

       Default: 2048 (rsa*), 256 (ecdsap256), 384 (ecdsap384), 256 (ed25519)

   zsk-size
       A length of newly generated ZSK keys.

       Default: see default for ksk-size

   ksk-shared
       If enabled, all zones with this policy assigned will share one KSK.

       Default: off

   dnskey-ttl
       A TTL value for DNSKEY records added into zone apex.

       Default: zone SOA TTL

       NOTE:
          Has infuence over ZSK key lifetime.

   zsk-lifetime
       A period between ZSK publication and the next rollover initiation.

       Default: 30 days

       NOTE:
          ZSK key lifetime is also infuenced by propagation-delay and dnskey-ttl

          Zero (aka infinity) value causes no ZSK rollover as a result.

   ksk-lifetime
       A period between KSK publication and the next rollover initiation.

       Default: 0

       NOTE:
          KSK key lifetime is also infuenced by propagation-delay, dnskey-ttl, and KSK submission
          delay.

          Zero (aka infinity) value causes no KSK rollover as a result.

          This applies for CSK lifetime if single-type-signing is enabled.

   propagation-delay
       An extra delay added for each key rollover step. This value should be high enough to cover
       propagation of data from the master server to all slaves.

       Default: 1 hour

       NOTE:
          Has infuence over ZSK key lifetime.

   rrsig-lifetime
       A validity period of newly issued signatures.

       Default: 14 days

   rrsig-refresh
       A period how long before a signature expiration the signature will be refreshed.

       Default: 7 days

   nsec3
       Specifies if NSEC3 will be used instead of NSEC.

       Default: off

   nsec3-iterations
       A number of additional times the hashing is performed.

       Default: 5

   nsec3-opt-out
       If set, NSEC3 records won't be created for insecure delegations.  This speeds up the  zone
       signing and reduces overall zone size.

       WARNING:
          NSEC3  with  the  Opt-Out  bit  set no longer works as a proof of non-existence in this
          zone.

       Default: off

   nsec3-salt-length
       A length of a salt field in octets, which is appended to the original  owner  name  before
       hashing.

       Default: 8

   nsec3-salt-lifetime
       A validity period of newly issued salt field.

       Default: 30 days

   ksk-submission
       A reference to submission section holding parameters of KSK submittion checks.

       Default: not set

   cds-cdnskey-publish
       Controls if and how shall the CDS and CDNSKEY be published in the zone.

       NOTE:
          This only applies if the zone keys are automatically managed by the server.

       Possible values:

       · none – Never publish any CDS or CDNSKEY records in the zone.

       · delete-dnssec – Publish special CDS and CDNSKEY records indicating turning off DNSSEC.

       · rollover – Publish CDS and CDNSKEY records only in the submission phase of KSK rollover.

       · always – Always publish CDS and CDNSKEY records for the current KSK.

       Default: always

REMOTE SECTION

       Definitions  of remote servers for outgoing connections (source of a zone transfer, target
       for a notification, etc.).

          remote:
            - id: STR
              address: ADDR[@INT] ...
              via: ADDR[@INT] ...
              key: key_id

   id
       A remote identifier.

   address
       An ordered list of destination IP addresses which are  used  for  communication  with  the
       remote  server.  The  addresses  are tried in sequence unless the operation is successful.
       Optional destination port (default  is  53)  can  be  appended  to  the  address  using  @
       separator.

       Default: not set

   via
       An  ordered  list  of  source  IP addresses. The first address with the same family as the
       destination address is used. Optional source port (default is random) can be  appended  to
       the address using @ separator.

       Default: not set

   key
       A  reference  to  the  TSIG  key  which is used to authenticate the communication with the
       remote server.

       Default: not set

TEMPLATE SECTION

       A template is a shareable zone setting which can be used for configuration of  many  zones
       in  one  place.  A  special default template (with the default identifier) can be used for
       global querying configuration or as an implicit  configuration  if  a  zone  doesn't  have
       another template specified.

          template:
            - id: STR
              timer-db: STR
              max-timer-db-size: SIZE
              journal-db: STR
              journal-db-mode: robust | asynchronous
              max-journal-db-size: SIZE
              kasp-db: STR
              max-kasp-db-size: SIZE
              global-module: STR/STR ...
              # All zone options (excluding 'template' item)

   id
       A template identifier.

   timer-db
       Specifies a path of the persistent timer database. The path can be specified as a relative
       path to the default template storage.

       NOTE:
          This option is only available in the default template.

       Default: storage/timers

   max-timer-db-size
       Hard limit for the timer database maximum size.

       NOTE:
          This option is only available in the default template.

       Default: 100 MiB

   journal-db
       Specifies a path of the persistent journal database.  The  path  can  be  specified  as  a
       relative path to the default template storage.

       NOTE:
          This option is only available in the default template.

       Default: storage/journal

   journal-db-mode
       Specifies journal LMDB backend configuration, which influences performance and durability.

       Possible values:

       · robust  –  The  journal  DB  disk  sychronization ensures DB durability but is generally
         slower.

       · asynchronous – The journal DB disk synchronization is optimized for  better  performance
         at the expense of lower DB durability; this mode is recommended only on slave nodes with
         many zones.

       NOTE:
          This option is only available in the default template.

       Default: robust

   max-journal-db-size
       Hard limit for the common journal DB. There is no cleanup logic in journal to recover from
       reaching  this  limit: journal simply starts refusing changes across all zones. Decreasing
       this value has no effect if lower than actual DB file size.

       It is recommended to limit max-journal-usage per-zone instead of max-journal-size in  most
       cases.  Please keep this value larger than the sum of all zones' journal usage limits. See
       more details regarding journal behaviour.

       This value also influences server's usage of virtual memory.

       NOTE:
          This option is only available in the default template.

       Default: 20 GiB (1 GiB for 32-bit)

   kasp-db
       A KASP database path. Non-absolute path is relative to storage.

       Default: storage/keys

       NOTE:
          This option is only available in the default template.

   max-kasp-db-size
       Hard limit for the KASP database maximum size.

       NOTE:
          This option is only available in the default template.

       Default: 500 MiB

   global-module
       An  ordered  list  of  references  to  query  modules  in  the  form  of  module_name   or
       module_name/module_id. These modules apply to all queries.

       NOTE:
          This option is only available in the default template.

       Default: not set

ZONE SECTION

       Definition of zones served by the server.

          zone:
            - domain: DNAME
              template: template_id
              storage: STR
              file: STR
              master: remote_id ...
              ddns-master: remote_id
              notify: remote_id ...
              acl: acl_id ...
              semantic-checks: BOOL
              disable-any: BOOL
              zonefile-sync: TIME
              zonefile-load: none | difference | difference-no-serial | whole
              journal-content: none | changes | all
              max-journal-usage: SIZE
              max-journal-depth: INT
              max-zone-size : SIZE
              dnssec-signing: BOOL
              dnssec-policy: STR
              request-edns-option: INT:[HEXSTR]
              serial-policy: increment | unixtime | dateserial
              min-refresh-interval: TIME
              max-refresh-interval: TIME
              module: STR/STR ...

   domain
       A zone name identifier.

   template
       A reference to a configuration template.

       Default: not set or default (if the template exists)

   storage
       A data directory for storing zone files, journal database, and timers database.

       Default: ${localstatedir}/lib/knot (configured with --with-storage=path)

   file
       A  path to the zone file. Non-absolute path is relative to storage. It is also possible to
       use the following formatters:

       · %c[N] or %c[N-M] – Means the Nth character or a sequence of  characters  beginning  from
         the Nth and ending with the Mth character of the textual zone name (see %s). The indexes
         are counted from 0 from the left. All dots (including the terminal one) are  considered.
         If the character is not available, the formatter has no effect.

       · %l[N] – Means the Nth label of the textual zone name (see %s). The index is counted from
         0 from the right (0 ~ TLD).  If the label is not available, the formatter has no effect.

       · %s – Means the current zone name in the textual representation.  The zone  name  doesn't
         include the terminating dot (the result for the root zone is the empty string!).

       · %% – Means the % character.

       WARNING:
          Beware of special characters which are escaped or encoded in the \DDD form where DDD is
          corresponding decimal ASCII code.

       Default: storage/%s.zone

   master
       An ordered list of references to zone master servers.

       Default: not set

   ddns-master
       A reference to zone primary master server.  If not specified, the first master  server  is
       used.

       Default: not set

   notify
       An  ordered  list  of  references  to  remotes to which notify message is sent if the zone
       changes.

       Default: not set

   acl
       An ordered list of references to ACL rules which can allow  or  disallow  zone  transfers,
       updates or incoming notifies.

       Default: not set

   semantic-checks
       If enabled, extra zone semantic checks are turned on.

       Several  checks  are  enabled  by  default and cannot be turned off. An error in mandatory
       checks causes zone not to be loaded. An error in extra checks is logged only.

       Mandatory checks:

       · SOA record missing in the zone (RFC 1034)

       · An extra record together with CNAME record except for RRSIG and DS (RFC 1034)

       · Multiple CNAME record with the same owner

       · DNAME record having a record under it (RFC 2672)

       Extra checks:

       · Missing NS record at the zone apex

       · Missing glue A or AAAA record

       · Invalid DNSKEY, DS, or NSEC3PARAM record

       · CDS or CDNSKEY inconsistency

       · Missing, invalid, or unverifiable RRSIG record

       · Invalid NSEC(3) record

       · Broken or non-cyclic NSEC(3) chain

       Default: off

   disable-any
       If enabled, all authoritative ANY queries sent over UDP will be  answered  with  an  empty
       response  and  with the TC bit set. Use this option to minimize the risk of DNS reflection
       attack.

       Default: off

   zonefile-sync
       The time after which the current zone in memory will be synced with a  zone  file  on  the
       disk  (see  file).  The  server will serve the latest zone even after a restart using zone
       journal, but the zone file on the disk will only be synced after  zonefile-sync  time  has
       expired  (or  after  manual  zone  flush). This is applicable when the zone is updated via
       IXFR, DDNS or automatic DNSSEC signing. In order to completely disable automatic zone file
       synchronization, set the value to -1. In that case, it is still possible to force a manual
       zone flush using the -f option.

       NOTE:
          If you are serving large zones with frequent updates where the immediate  sync  with  a
          zone file is not desirable, increase the value.

       Default: 0 (immediate)

   zonefile-load
       Selects how the zone file contents are applied during zone load.

       Possible values:

       · none – The zone file is not used at all.

       · difference  –  If the zone contents are already available during server start or reload,
         the difference is computed between  them  and  the  contents  of  the  zone  file.  This
         difference is then checked for semantic errors and applied to the current zone contents.

       · difference-no-serial  –  Same  as  difference,  but  the  SOA serial in the zone file is
         ignored, the server takes care of incrementing the serial automatically.

       · whole – Zone contents are loaded from the zone file.

       When difference is configured and there are no zone contents yet (cold start of  Knot  and
       no zone contents in journal), it behaves the same way like whole.

       Default: whole

   journal-content
       Selects how the journal shall be used to store zone and its changes.

       Possible values:

       · none – The journal is not used at all.

       · changes – Zone changes history is stored in journal.

       · all – Zone contents and history is stored in journal.

       Default: changes

   max-journal-usage
       Policy how much space in journal DB will the zone's journal occupy.

       Default: 100 MiB

       NOTE:
          Journal DB may grow far above the sum of max-journal-usage across all zones, because of
          DB free space fragmentation.

   max-journal-depth
       Maximum history length of journal.

       Minimum: 2

       Default: 2^64

   max-zone-size
       Maximum size of the zone. The size is measured as size of the zone records in wire  format
       without  compression.  The  limit  is  enforced  for  incoming  zone transfers and dynamic
       updates.

       For incremental transfers (IXFR), the effective limit for the total size of the records in
       the  transfer  is  twice  the  configured  value.  However the final size of the zone must
       satisfy the configured value.

       Default: 2^64

   dnssec-signing
       If enabled, automatic DNSSEC signing for the zone is turned on.

       Default: off

   dnssec-policy
       A reference to DNSSEC signing policy. A special default value can be used for the  default
       policy settings.

       Required

   request-edns-option
       An  arbitrary  EDNS0  option  which is included into a server request (AXFR, IXFR, SOA, or
       NOTIFY). The value is in the option_code:option_data format.

       Default: not set

   serial-policy
       Specifies how the zone serial is updated  after  a  dynamic  update  or  automatic  DNSSEC
       signing. If the serial is changed by the dynamic update, no change is made.

       Possible values:

       · increment – The serial is incremented according to serial number arithmetic.

       · unixtime – The serial is set to the current unix time.

       · dateserial  –  The 10-digit serial (YYYYMMDDnn) is incremented, the first 8 digits match
         the current iso-date.

       NOTE:
          In case of unixtime, if the resulting serial is lower or equal than current zone  (this
          happens  e.g. in case of migrating from other policy or frequent updates) the serial is
          incremented instead.

          Use dateserial only if you expect less than 100 updates per day per zone.

       Default: increment

   min-refresh-interval
       Forced minimum zone refresh interval to avoid flooding master.

       Default: 2

   max-refresh-interval
       Forced maximum zone refresh interval.

       Default: not set

   module
       An  ordered  list  of  references  to  query  modules  in  the  form  of  module_name   or
       module_name/module_id. These modules apply only to the current zone queries.

       Default: not set

LOGGING SECTION

       Server  can be configured to log to the standard output, standard error output, syslog (or
       systemd journal if systemd is enabled) or into an arbitrary file.

       There are 6 logging severity levels:

       · critical – Non-recoverable error resulting in server shutdown.

       · error – Recoverable error, action should be taken.

       · warning – Warning that might require user action.

       · notice – Server notice or hint.

       · info – Informational message.

       · debug – Debug messages (must be turned on at compile time).

       In the case of missing log section, warning or more serious messages  will  be  logged  to
       both  standard  error  output  and  syslog. The info and notice messages will be logged to
       standard output.

          log:
            - target: stdout | stderr | syslog | STR
              server: critical | error | warning | notice | info | debug
              control: critical | error | warning | notice | info | debug
              zone: critical | error | warning | notice | info | debug
              any: critical | error | warning | notice | info | debug

   target
       A logging output.

       Possible values:

       · stdout – Standard output.

       · stderr – Standard error output.

       · syslog – Syslog.

       · file_name – A specific file.

   server
       Minimum severity level for messages related to general operation of the  server  that  are
       logged.

       Default: not set

   control
       Minimum severity level for messages related to server control that are logged.

       Default: not set

   zone
       Minimum severity level for messages related to zones that are logged.

       Default: not set

   any
       Minimum severity level for all message types that are logged.

       Default: not set

AUTHOR

       CZ.NIC Labs <https://www.knot-dns.cz>

COPYRIGHT

       Copyright 2010–2019, CZ.NIC, z.s.p.o.