Provided by: bind9-utils_9.20.11-1ubuntu2_amd64 
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 | -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 -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
9.20.11-1ubuntu2-Ubuntu 2025-07-04 RNDC(8)