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knotc - Man Page

Knot DNS control utility

Examples (TL;DR)


knotc [config_option] [options] [action]


This program controls a running knotd process using a socket.

If an action is specified, it is performed and knotc exits, otherwise the program is executed in the interactive mode.

Config options

-c,  --config file

Use a textual configuration file (default is /etc/knot/knot.conf).

-C,  --confdb directory

Use a binary configuration database directory (default is /var/lib/knot/confdb). The default configuration database, if exists, has a preference to the default configuration file.


-m,  --max-conf-size MiB

Set maximum size of the configuration database (default is 500 MiB, maximum 10000 MiB).

-s,  --socket path

Use a control UNIX socket path (default is /run/knot/knot.sock).

-t,  --timeout seconds

Use a control timeout in seconds. Set to 0 for infinity (default is 60). The control socket operations are also subject to the timeout parameter set on the server side in server's Control configuration section.

-b,  --blocking

Zone event trigger commands wait until the event is finished. Control timeout is set to infinity if not forced by explicit timeout specification.

-e,  --extended

Show extended output (even empty items in zone status).

-f,  --force

Forced operation. Overrides some checks.

-x,  --mono

Don't generate colorized output.

-X,  --color

Force colorized output in extended output or to a pipe.

-v,  --verbose

Enable debug output.

-h,  --help

Print the program help.

-V,  --version

Print the program version.


status [detail]

Check if the server is running. Details are version for the running server version, workers for the numbers of worker threads, configure for the configure summary, or cert-key for the public key pin of the currently used certificate.


Stop the server if running.


Reload the server configuration and modified zone files, and reopen the log files if they are configured. All open zone transactions will be aborted!

stats [module[.counter]]

Show global statistics counter(s). To print also counters with value 0, use force option.

zone-check [zone...]

Test if the server can load the zone. Semantic checks are executed if enabled in the configuration. If invoked with the force option, an error is returned when semantic check warning appears. (*)

zone-status [zone...] [filter]

Show the zone status. Filters are +role, +serial, +transaction, +events, +freeze, and +catalog. Empty zone parameters are omitted, unless the --extended option is used. A single dash in the output represents an unset value. Automatic colorization can be overruled using the --mono and --color options.

The color code is: green - zone acts as a master / red - zone acts as a slave, bold font (highlited) - zone is active / normal - zone is empty, underscored - zone is an interpreted catalog member.

zone-reload [zone...]

Trigger a zone reload from a disk without checking its modification time. For secondary zone, the refresh event from primary server(s) is scheduled; for primary zone, the notify event to secondary server(s) is scheduled. An open zone transaction will be aborted! If invoked with the force option, also zone modules will be re-loaded, but blocking mode might not work reliably. (#)

zone-refresh [zone...]

Trigger a check for the zone serial on the zone's primary server. If the primary server has a newer zone, a transfer is scheduled. This command is valid for secondary zones. (#)

zone-retransfer [zone...]

Trigger a zone transfer from the zone's primary server. The server doesn't check the serial of the primary server's zone. This command is valid for secondary zones. (#)

zone-notify [zone...]

Trigger a NOTIFY message to all configured remotes. This can help in cases when previous NOTIFY had been lost or the secondary servers have been offline. (#)

zone-flush [zone...] [+outdir directory]

Trigger a zone journal flush to the configured zone file. If an output directory is specified, the current zone is immediately dumped (in the blocking mode) to a zone file in the specified directory. See Notes below about the directory permissions. (#)

zone-backup [zone...] +backupdir directory [filter...]

Trigger a zone data and metadata backup to a specified directory. Available filters are +zonefile, +journal, +timers, +kaspdb, +keysonly, +catalog, +quic, and their negative counterparts +nozonefile, +nojournal, +notimers, +nokaspdb, +nokeysonly, +nocatalog, and +noquic. With these filters set, zone contents, zone's journal, zone-related timers, zone-related data in the KASP database together with keys (or keys without the KASP database), zone's catalog, and the server QUIC key and certificate, respectively, are backed up, or omitted from the backup. By default, filters +zonefile, +timers, +kaspdb, +catalog, +quic, +nojournal, and +nokeysonly are set for backup. The same defaults are set for restore, with the only difference being +noquic. Setting a filter for an item doesn't change the default settings for other items. The only exception is +keysonly, which disables all other filters by default, but they can still be turned on explicitly. If zone flushing is disabled, the original zone file is backed up instead of writing out zone contents to a file. When backing-up a catalog zone, it is recommended to prevent ongoing changes to it by use of zone-freeze. See Notes below about the directory permissions. (#)

zone-restore [zone...] +backupdir directory [filter...]

Trigger a zone data and metadata restore from a specified backup directory. Optional filters are equivalent to the same filters of zone-backup. Restore from backups created by Knot DNS releases prior to 3.1 is possible with the force option. See Notes below about the directory permissions. (#)

zone-sign [zone...]

Trigger a DNSSEC re-sign of the zone. Existing signatures will be dropped. This command is valid for zones with DNSSEC signing enabled. (#)

zone-keys-load [zone...]

Trigger a load of DNSSEC keys and other signing material from KASP database (which might have been altered manually). If suitable, re-sign the zone afterwards (keeping valid signatures intact). (#)

zone-key-rollover zone key_type

Trigger immediate key rollover. Publish new key and start a key rollover, even when the key has a lifetime to go. Key type can be ksk (also for CSK) or zsk. This command is valid for zones with DNSSEC signing and automatic key management enabled. Note that complete key rollover consists of several steps and the blocking mode relates to the initial one only! (#)

zone-ksk-submitted zone...

Use when the zone's KSK rollover is in submission phase. By calling this command the user confirms manually that the parent zone contains DS record for the new KSK in submission phase and the old KSK can be retired. (#)

zone-freeze [zone...]

Trigger a zone freeze. All running events will be finished and all new and pending (planned) zone-changing events (load, refresh, update, flush, and DNSSEC signing) will be held up until the zone is thawed. (#)

zone-thaw [zone...]

Trigger dismissal of zone freeze. (#)

zone-xfr-freeze [zone...]

Temporarily disable outgoing AXFR/IXFR for the zone(s). (#)

zone-xfr-thaw [zone...]

Dismiss outgoing XFR freeze. (#)

zone-read zone [owner [type]]

Get zone data that are currently being presented.

zone-begin zone...

Begin a zone transaction.

zone-commit zone...

Commit the zone transaction. All changes are applied to the zone.

zone-abort zone...

Abort the zone transaction. All changes are discarded.

zone-diff zone

Get zone changes within the transaction.

zone-get zone [owner [type]]

Get zone data within the transaction.

zone-set zone owner [ttl] type rdata

Add zone record within the transaction. The first record in a rrset requires a ttl value specified.

zone-unset zone owner [type [rdata]]

Remove zone data within the transaction.

zone-purge zone... [+orphan] [filter...]

Purge zone data, zone file, journal, timers, and/or KASP data of specified zones. Available filters are +expire, +zonefile, +journal, +timers, +kaspdb, and +catalog. If no filter is specified, all filters are enabled. If the zone is no longer configured, add +orphan parameter (zone file cannot be purged in this case). When purging orphans, always check the server log for possible errors. For proper operation, it's necessary to prevent ongoing changes to the zone and triggering of zone related events during purge; use of zone-freeze is advisable. This command always requires the force option. (#)

zone-stats zone [module[.counter]]

Show zone statistics counter(s). To print also counters with value 0, use force option.


Initialize the configuration database. If the database doesn't exist yet, execute this command as an intended user to ensure the server is permitted to access the database (e.g. sudo -u knot knotc conf-init). (*)


Check the server configuration. (*)

conf-import filename [+nopurge]

Import a configuration file into the configuration database. If the database doesn't exist yet, execute this command as an intended user to ensure the server is permitted to access the database (e.g. sudo -u knot knotc conf-import ...). An optional filter +nopurge prevents possibly existing configuration database from purging before the import itself. Also ensure the server is not using the configuration database at the same time! (*)

conf-export [filename] [+schema]

Export the configuration database (or JSON schema) into a file or stdout. (*)

conf-list [item]

List the configuration database sections or section items.

conf-read [item]

Read the item from the active configuration database.


Begin a writing configuration database transaction. Only one transaction can be opened at a time.


Commit the configuration database transaction.


Rollback the configuration database transaction.

conf-diff [item]

Get the item difference in the transaction.

conf-get [item]

Get the item data from the transaction.

conf-set item [data...]

Set the item data in the transaction.

conf-unset [item] [data...]

Unset the item data in the transaction.


Empty or -- zone parameter means all zones or all zones with a transaction.

Use @ owner to denote the zone name.

Type item parameter in the form of section[[id]][.name].

(*) indicates a local operation which requires a configuration.

(#) indicates an optionally blocking operation.

The -b and -f options can be placed right after the command name.

Responses returned by knotc commands depend on the mode:

  • In the blocking mode, knotc reports if an error occurred during processing of the command by the server. If an error is reported, a more detailed information about the failure can usually be found in the server log.
  • In the non-blocking (default) mode, knotc doesn't report processing errors. The OK response to triggering commands means that the command has been successfully sent to the server. To verify if the operation succeeded, it's necessary to check the server log.

Actions zone-flush, zone-backup, and zone-restore are carried out by the knotd process. The directory specified must be accessible to the user account that knotd runs under and if the directory already exists, its permissions must be appropriate for that user account.

Interactive mode

The utility provides interactive mode with basic line editing functionality, command completion, and command history.

Interactive mode behavior can be customized in ~/.editrc. Refer to editrc(5) for details.

Command history is saved in ~/.knotc_history.

Exit Values

Exit status of 0 means successful operation. Any other exit status indicates an error.


Reload the whole server configuration

$ knotc reload

Flush the example.com and example.org zones

$ knotc zone-flush example.com example.org

Get the current server configuration

$ knotc conf-read server

Get the list of the current zones

$ knotc conf-read zone.domain

Get the primary servers for the example.com zone

$ knotc conf-read 'zone[example.com].master'

Add example.org zone with a zonefile location

$ knotc conf-begin
$ knotc conf-set 'zone[example.org]'
$ knotc conf-set 'zone[example.org].file' '/var/zones/example.org.zone'
$ knotc conf-commit

Get the SOA record for each configured zone

$ knotc zone-read -- @ SOA

See Also

knotd(8), knot.conf(5), editrc(5).


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

Referenced By

keymgr(8), knotd(8), knsec3hash(1).

2024-06-25 3.3.7 Knot DNS