RNDC(8)

NAME
rndc - name server control utility

SYNOPSIS

rndc [-b source-address] [-c config-file] [-k key-file] [-s server] [-p port] [-q] [-r] [-V] [-y server_key] [[-4] | [-6]] {command}

DESCRIPTION

rndc controls the operation of a name server. If rndc is invoked with no command line options or arguments, it prints a short summary of the supported commands and the available options and their arguments.

rndc communicates with the name server over a TCP connection, sending commands authenticated with digital signatures. In the current versions of rndc and named, the only supported authentication algorithms are HMAC-MD5 (for compatibility), HMAC-SHA1, HMAC-SHA224, HMAC-SHA256 (default), HMAC-SHA384, and HMAC-SHA512. They use a shared secret on each end of the connection, which provides TSIG-style authentication for the command request and the name server's response. All commands sent over the channel must be signed by a server_key known to the server.

rndc reads a configuration file to determine how to contact the name server and decide what algorithm and key it should use.

OPTIONS

    -4  This option indicates use of IPv4 only.

    -6  This option indicates use of IPv6 only.

    -b source-address
        This option indicates source-address as the source address for the connection to the server. Multiple instances are permitted, to allow setting of both the IPv4 and IPv6 source addresses.

    -c config-file
        This option indicates config-file as the configuration file instead of the default, /etc/bind/rndc.conf.

    -k key-file
        This option indicates key-file as the key file instead of the default, /etc/bind/rndc.key. The key in /etc/bind/rndc.key is used to authenticate commands sent to the server if the config-file does not exist.

    -s server
        server is the name or address of the server which matches a server statement in the configuration file for rndc. If no server is supplied on the command line, the host named by the default-server clause in the options statement of the rndc configuration file is used.

    -p port
        This option instructs BIND 9 to send commands to TCP port port instead of its default control channel port, 953.

    -q  This option sets quiet mode, where message text returned by the server is not printed unless there is an error.

    -r  This option instructs rndc to print the result code returned by named after executing the requested command (e.g., ISC_R_SUCCESS, ISC_R_FAILURE, etc.).

    -t timeout
        This option sets the idle timeout period for rndc to timeout seconds. The default is 60 seconds, and the maximum settable value is 86400 seconds (1 day). If set to 0, there is no timeout.

    -V  This option enables verbose logging.

    -y server_key
        This option indicates use of the key server_key from the configuration file. For control message validation to succeed, server_key must be known by named with the same algorithm and secret string. If no server_key is specified, rndc first looks for a key clause in the server statement of the server being used, or if no server statement is present for that host, then in the default-key clause of the options statement. Note that the configuration file contains shared secrets which are used to send authenticated control commands to name servers, and should therefore not have general read or write access.

COMMANDS

A list of commands supported by rndc can be seen by running rndc without arguments.

Currently supported commands are:

    addzone zone [class [view]] configuration
        This command adds a zone while the server is running. This command requires the allow-new-zones option to be set to yes. The configuration string specified on the command line is the zone configuration text that would ordinarily be placed in named.conf.

        The configuration is saved in a file called viewname.nzf (or, if named is compiled with liblmdb, an LMDB database file called viewname.nzd). viewname is the name of the view, unless the view name contains characters that are incompatible with use as a file name, in which case a cryptographic hash of the view name is used instead. When named is restarted, the file is loaded into the view configuration so that zones that were added can persist after a restart.

        This sample addzone command adds the zone example.com to the default view:

        rndc addzone example.com '{ type primary; file "example.com.db"; };'

        (Note the brackets around and semi-colon after the zone configuration text.)

        See also rndc delzone and rndc modzone.

    delzone [-clean] zone [class [view]]
        This command deletes a zone while the server is running.

        If the -clean argument is specified, the zone's master file (and journal file, if any) are deleted along with the zone. Without the -clean option, zone files must be deleted manually. (If the zone is of type secondary or stub, the files needing to be removed are reported in the output of the rndc delzone command.)

        If the zone was originally added via rndc addzone, then it is removed permanently. However, if it was originally configured in named.conf, then that original configuration remains in place; when the server is restarted or reconfigured, the zone is recreated. To remove it permanently, it must also be removed from named.conf.

        See also rndc addzone and rndc modzone.

    dnssec (-status | -step | -rollover -key id [-alg algorithm] [-when time] | -checkds [-key id [-alg algorithm]] [-when time] published | withdrawn)) zone [class [view]]
        This command allows you to interact with the "dnssec-policy" of a given zone.

        rndc dnssec -status show the DNSSEC signing state for the specified zone.

        rndc dnssec -step sends a signal to an instance of named for a zone configured with dnssec-policy in manual mode, telling it to continue with the operations that had previously been blocked but logged. This gives the human operator a chance to review the log messages, understand what will happen next and then, using rndc dnssec -step, to inform named to proceed to the next stage.

        rndc dnssec -rollover allows you to schedule key rollover for a specific key (overriding the original key lifetime).

        rndc dnssec -checkds informs named that the DS for a specified zone's key-signing key has been confirmed to be published in, or withdrawn from, the parent zone. This is required in order to complete a KSK rollover. The -key id and -alg algorithm arguments can be used to specify a particular KSK, if necessary; if there is only one key acting as a KSK for the zone, these arguments can be omitted. The time of publication or withdrawal for the DS is set to the current time by default, but can be overridden to a specific time with the argument -when time, where time is expressed in YYYYMMDDHHMMSS notation.

    dnstap (-reopen | -roll [number])
        This command closes and re-opens DNSTAP output files.

        rndc dnstap -reopen allows the output file to be renamed externally, so that named can truncate and re-open it.

        rndc dnstap -roll causes the output file to be rolled automatically, similar to log files. The most recent output file has ".0" appended to its name; the previous most recent output file is moved to ".1", and so on. If number is specified, then the number of backup log files is limited to that number.

    dumpdb [-all | -cache | -zones | -adb | -bad | -expired | -fail] [view ...]
        This command dumps the server's caches (default) and/or zones to the dump file for the specified views. If no view is specified, all views are dumped. (See the dump-file option in the BIND 9 Administrator Reference Manual.)

    fetchlimit [view]
        This command dumps a list of servers that are currently being rate-limited as a result of fetches-per-server settings, and a list of domain names that are currently being rate-limited as a result of fetches-per-zone settings.

    flush
        This command flushes the server's cache.

    flushname name [view]
        This command flushes the given name from the view's DNS cache and, if applicable, from the view's nameserver address database, bad server cache, and SERVFAIL cache.

    flushtree name [view]
        This command flushes the given name, and all of its subdomains, from the view's DNS cache, address database, bad server cache, and SERVFAIL cache.

    freeze [zone [class [view]]]
        This command suspends updates to a dynamic zone. If no zone is specified, then all zones are suspended. This allows manual edits to be made to a zone normally updated by dynamic update, and causes changes in the journal file to be synced into the master file. All dynamic update attempts are refused while the zone is frozen.

        See also rndc thaw.

    halt [-p]
        This command stops the server immediately. Recent changes made through dynamic update or IXFR are not saved to the master files, but are rolled forward from the journal files when the server is restarted. If -p is specified, named's process ID is returned. This allows an external process to determine when named has completed halting.

        See also rndc stop.

    skr -import file zone [class [view]]
        This command allows you to import a SKR file for the specified zone, to support offline KSK signing.

    loadkeys [zone [class [view]]]
        This command fetches all DNSSEC keys for the given zone from the key directory. If they are within their publication period, they are merged into the zone's DNSKEY RRset. Unlike rndc sign, however, the zone is not immediately re-signed by the new keys, but is allowed to incrementally re-sign over time.

        This command requires that the zone be configured with a dnssec-policy, and also requires the zone to be configured to allow dynamic DNS. (See "Dynamic Update Policies" in the Administrator Reference Manual for more details.)

    managed-keys (status | refresh | sync | destroy) [class [view]]
        This command inspects and controls the "managed-keys" database which handles RFC 5011 DNSSEC trust anchor maintenance. If a view is specified, these commands are applied to that view; otherwise, they are applied to all views.

        •   When run with the status keyword, this prints the current status of the managed-keys database.

        •   When run with the refresh keyword, this forces an immediate refresh query to be sent for all the managed keys, updating the managed-keys database if any new keys are found, without waiting the normal refresh interval.

        •   When run with the sync keyword, this forces an immediate dump of the managed-keys database to disk (in the file managed-keys.bind or (viewname.mkeys). This synchronizes the database with its journal file, so that the database's current contents can be inspected visually.

        •   When run with the destroy keyword, the managed-keys database is shut down and deleted, and all key maintenance is terminated. This command should be used only with extreme caution.

            Existing keys that are already trusted are not deleted from memory; DNSSEC validation can continue after this command is used. However, key maintenance operations cease until named is restarted or reconfigured, and all existing key maintenance states are deleted.

            Running rndc reconfig or restarting named immediately after this command causes key maintenance to be reinitialized from scratch, just as if the server were being started for the first time. This is primarily intended for testing, but it may also be used, for example, to jumpstart the acquisition of new keys in the event of a trust anchor rollover, or as a brute-force repair for key maintenance problems.

    memprof [(on | off | dump)]
        This command controls memory profiling. To have any effect, named must be built with jemalloc, the library have profiling support enabled and run with the prof:true allocator configuration. (either via MALLOC_CONF or /etc/malloc.conf)

        The prof_active:false option is recommended to ensure the profiling overhead does not affect named when not needed.

        The on and off options will start and stop the jemalloc memory profiling respectively. When run with the dump option, named will dump the profile to the working directory. The name will be chosen automatically by jemalloc.

    modzone zone [class [view]] configuration
        This command modifies the configuration of a zone while the server is running. This command requires the allow-new-zones option to be set to yes. As with addzone, the configuration string specified on the command line is the zone configuration text that would ordinarily be placed in named.conf.

        If the zone was originally added via rndc addzone, the configuration changes are recorded permanently and are still in effect after the server is restarted or reconfigured. However, if it was originally configured in named.conf, then that original configuration remains in place; when the server is restarted or reconfigured, the zone reverts to its original configuration. To make the changes permanent, it must also be modified in named.conf.

        See also rndc addzone and rndc delzone.

    notify zone [class [view]]
        This command resends NOTIFY messages for the zone.

    notrace
        This command sets the server's debugging level to 0.

        See also rndc trace.

    nta [(-class class | -dump | -force | -remove | -lifetime duration)] domain [view]
        This command sets a DNSSEC negative trust anchor (NTA) for domain, with a lifetime of duration. The default lifetime is configured in named.conf via the nta-lifetime option, and defaults to one hour. The lifetime cannot exceed one week.

        A negative trust anchor selectively disables DNSSEC validation for zones that are known to be failing because of misconfiguration rather than an attack. When data to be validated is at or below an active NTA (and above any other configured trust anchors), named aborts the DNSSEC validation process and treats the data as insecure rather than bogus. This continues until the NTA's lifetime has elapsed.

        NTAs persist across restarts of the named server. The NTAs for a view are saved in a file called name.nta, where name is the name of the view; if it contains characters that are incompatible with use as a file name, a cryptographic hash is generated from the name of the view.

        An existing NTA can be removed by using the -remove option.

        An NTA's lifetime can be specified with the -lifetime option. TTL-style suffixes can be used to specify the lifetime in seconds, minutes, or hours. If the specified NTA already exists, its lifetime is updated to the new value. Setting lifetime to zero is equivalent to -remove.

        If -dump is used, any other arguments are ignored and a list of existing NTAs is printed. Note that this may include NTAs that are expired but have not yet been cleaned up.

        Normally, named periodically tests to see whether data below an NTA can now be validated (see the nta-recheck option in the Administrator Reference Manual for details). If data can be validated, then the NTA is regarded as no longer necessary and is allowed to expire early. The -force parameter overrides this behavior and forces an NTA to persist for its entire lifetime, regardless of whether data could be validated if the NTA were not present.

        The view class can be specified with -class. The default is class IN, which is the only class for which DNSSEC is currently supported.

        All of these options can be shortened, i.e., to -l, -r, -d, -f, and -c.

        Unrecognized options are treated as errors. To refer to a domain or view name that begins with a hyphen, use a double-hyphen (--) on the command line to indicate the end of options.

    querylog [(on | off)]
        This command enables or disables query logging. For backward compatibility, this command can also be used without an argument to toggle query logging on and off.

        Query logging can also be enabled by explicitly directing the queries category to a channel in the logging section of named.conf, or by specifying querylog yes; in the options section of named.conf.

    reconfig
        This command reloads the configuration file and loads new zones, but does not reload existing zone files even if they have changed. This is faster than a full rndc reload when there is a large number of zones, because it avoids the need to examine the modification times of the zone files.

    recursing
        This command dumps the list of queries named is currently recursing on, and the list of domains to which iterative queries are currently being sent.

        The first list includes all unique clients that are waiting for recursion to complete, including the query that is awaiting a response and the timestamp (seconds since the Unix epoch) of when named started processing this client query.

        The second list comprises of domains for which there are active (or recently active) fetches in progress. It reports the number of active fetches for each domain and the number of queries that have been passed (allowed) or dropped (spilled) as a result of the fetches-per-zone limit. (Note: these counters are not cumulative over time; whenever the number of active fetches for a domain drops to zero, the counter for that domain is deleted, and the next time a fetch is sent to that domain, it is recreated with the counters set to zero).

    refresh zone [class [view]]
        This command schedules zone maintenance for the given zone.

    reload
        This command reloads the configuration file and zones.

        zone [class [view]]

    If a zone is specified, this command reloads only the given zone. If no zone is specified, the reloading happens asynchronously.

    reset-stats <counter-name ...>
        This command resets the requested statistics counters.

        At least one counter name must be provided. Currently the following counters are supported: recursive-high-water, tcp-high-water.

    responselog [on | off]
        This command enables or disables response logging. For backward compatibility, this command can also be used without an argument to toggle response logging on and off.

        Unlike query logging, response logging cannot be enabled by explicitly directing the responses category to a channel in the logging section of named.conf, but it can still be enabled by specifying responselog yes; in the options section of named.conf.

    retransfer [-force] zone [class [view]]
        This command retransfers the given secondary zone from the primary server.

        If the zone is configured to use inline-signing, the signed version of the zone is discarded; after the retransfer of the unsigned version is complete, the signed version is regenerated with new signatures. With the optional -force argument provided if there is an ongoing zone transfer it will be aborted before a new zone transfer is scheduled.

    scan
        This command scans the list of available network interfaces for changes, without performing a full rndc reconfig or waiting for the interface-interval timer.

    secroots [-] [view ...]
        This command dumps the security roots (i.e., trust anchors configured via trust-anchors, or the managed-keys or trusted-keys statements [both deprecated], or dnssec-validation auto) and negative trust anchors for the specified views. If no view is specified, all views are dumped. Security roots indicate whether they are configured as trusted keys, managed keys, or initializing managed keys (managed keys that have not yet been updated by a successful key refresh query).

        If the first argument is -, then the output is returned via the rndc response channel and printed to the standard output. Otherwise, it is written to the secroots dump file, which defaults to named.secroots, but can be overridden via the secroots-file option in named.conf.

        See also rndc managed-keys.

    serve-stale (on | off | reset | status) [class [view]]
        This command enables, disables, resets, or reports the current status of the serving of stale answers as configured in named.conf.

        If serving of stale answers is disabled by rndc-serve-stale off, then it remains disabled even if named is reloaded or reconfigured. rndc serve-stale reset restores the setting as configured in named.conf.

        rndc serve-stale status reports whether caching and serving of stale answers is currently enabled or disabled. It also reports the values of stale-answer-ttl and max-stale-ttl.

    showzone zone [class [view]]
        This command prints the configuration of a running zone.

        See also rndc zonestatus.

    sign zone [class [view]]
        This command fetches all DNSSEC keys for the given zone from the key directory (see the key-directory option in the BIND 9 Administrator Reference Manual). If they are within their publication period, they are merged into the zone's DNSKEY RRset. If the DNSKEY RRset is changed, then the zone is automatically re-signed with the new key set.

        This command requires that the zone be configured with a dnssec-policy, and also requires the zone to be configured to allow dynamic DNS. (See "Dynamic Update Policies" in the Administrator Reference Manual for more details.)

        See also rndc loadkeys.

    signing [(-list | -clear keyid/algorithm | -clear all | -nsec3param (parameters | none) | -serial value) zone [class [view]]
        This command lists, edits, or removes the DNSSEC signing-state records for the specified zone. The status of ongoing DNSSEC operations, such as signing or generating NSEC3 chains, is stored in the zone in the form of DNS resource records of type sig-signing-type. rndc signing -list converts these records into a human-readable form, indicating which keys are currently signing or have finished signing the zone, and which NSEC3 chains are being created or removed.

        rndc signing -clear can remove a single key (specified in the same format that rndc signing -list uses to display it), or all keys. In either case, only completed keys are removed; any record indicating that a key has not yet finished signing the zone is retained.

        rndc signing -nsec3param sets the NSEC3 parameters for a zone. This is the only supported mechanism for using NSEC3 with inline-signing zones. Parameters are specified in the same format as an NSEC3PARAM resource record: hash algorithm, flags, iterations, and salt, in that order.

        Currently, the only defined value for hash algorithm is 1, representing SHA-1. The flags may be set to 0 or 1, depending on whether the opt-out bit in the NSEC3 chain should be set. iterations defines the number of additional times to apply the algorithm when generating an NSEC3 hash. The salt is a string of data expressed in hexadecimal, a hyphen (-) if no salt is to be used, or the keyword auto, which causes named to generate a random 64-bit salt.

        The only recommended configuration is rndc signing -nsec3param 1 0 0 - zone, i.e. no salt, no additional iterations, no opt-out.

        WARNING:
            Do not use extra iterations, salt, or opt-out unless all their implications are fully understood. A higher number of iterations causes interoperability problems and opens servers to CPU-exhausting DoS attacks.

    rndc signing -nsec3param none removes an existing NSEC3 chain and replaces it with NSEC.

    rndc signing -serial value sets the serial number of the zone to value. If the value would cause the serial number to go backwards, it is rejected. The primary use of this parameter is to set the serial number on inline signed zones.

    stats
        This command writes server statistics to the statistics file. (See the statistics-file option in the BIND 9 Administrator Reference Manual.)

    status
        This command displays the status of the server. Note that the number of zones includes the internal bind/CH zone and the default ./IN hint zone, if there is no explicit root zone configured.

    stop -p
        This command stops the server, making sure any recent changes made through dynamic update or IXFR are first saved to the master files of the updated zones. If -p is specified, named's process ID is returned. This allows an external process to determine when named has completed stopping.

        See also rndc halt.

    sync -clean [zone [class [view]]]
        This command syncs changes in the journal file for a dynamic zone to the master file. If the "-clean" option is specified, the journal file is also removed. If no zone is specified, then all zones are synced.

    tcp-timeouts [initial idle keepalive advertised]
        When called without arguments, this command displays the current values of the tcp-initial-timeout, tcp-idle-timeout, tcp-keepalive-timeout, and tcp-advertised-timeout options. When called with arguments, these values are updated. This allows an administrator to make rapid adjustments when under a denial-of-service (DoS) attack. See the descriptions of these options in the BIND 9 Administrator Reference Manual for details of their use.

    thaw [zone [class [view]]]
        This command enables updates to a frozen dynamic zone. If no zone is specified, then all frozen zones are enabled. This causes the server to reload the zone from disk, and re-enables dynamic updates after the load has completed. After a zone is thawed, dynamic updates are no longer refused. If the zone has changed and the ixfr-from-differences option is in use, the journal file is updated to reflect changes in the zone. Otherwise, if the zone has changed, any existing journal file is removed. If no zone is specified, the reloading happens asynchronously.

        See also rndc freeze.

    trace [level]
        If no level is specified, this command increments the server's debugging level by one.

        level
            If specified, this command sets the server's debugging level to the provided value.

    See also rndc notrace.

    validation (on | off | status) [view ...]
        This command enables, disables, or checks the current status of DNSSEC validation. By default, validation is enabled.

        The cache is flushed when validation is turned on or off to avoid using data that might differ between states.

    zonestatus zone [class [view]]
        This command displays the current status of the given zone, including the master file name and any include files from which it was loaded, when it was most recently loaded, the current serial number, the number of nodes, whether the zone supports dynamic updates, whether the zone is DNSSEC signed, whether it uses automatic DNSSEC key management or inline signing, and the scheduled refresh or expiry times for the zone.

        See also rndc showzone.

rndc commands that specify zone names, such as reload retransfer, or zonestatus, can be ambiguous when applied to zones of type redirect. Redirect zones are always called ., and can be confused with zones of type hint or with secondary copies of the root zone. To specify a redirect zone, use the special zone name -redirect, without a trailing period. (With a trailing period, this would specify a zone called "-redirect".)

LIMITATIONS

There is currently no way to provide the shared secret for a server_key without using the configuration file.

Several error messages could be clearer.

SEE ALSO

rndc.conf(5), rndc-confgen(8), named(8), named.conf(5), BIND 9 Administrator Reference Manual.

AUTHOR
Internet Systems Consortium

COPYRIGHT
2025, Internet Systems Consortium