rndc — name server control utility


rndc [-b source-address] [-c config-file] [-k key-file] [-s server] [-p port] [-q] [-V] [-y key_id] {command}


rndc controls the operation of a name server. It supersedes the ndc utility that was provided in old BIND releases. 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. This 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 key_id 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.


-b source-address

Use 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

Use config-file as the configuration file instead of the default, /etc/rndc.conf.

-k key-file

Use key-file as the key file instead of the default, /etc/rndc.key. The key in /etc/rndc.key will be 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 will be used.

-p port

Send commands to TCP port port instead of BIND 9's default control channel port, 953.


Quiet mode: Message text returned by the server will not be printed except when there is an error.


Enable verbose logging.

-y key_id

Use the key key_id from the configuration file. key_id must be known by named with the same algorithm and secret string in order for control message validation to succeed. If no key_id is specified, rndc will first look for a key clause in the server statement of the server being used, or if no server statement is present for that host, then 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. It should therefore not have general read or write access.


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

Currently supported commands are:


Reload configuration file and zones.

reload zone [class [view]]

Reload the given zone.

refresh zone [class [view]]

Schedule zone maintenance for the given zone.

retransfer zone [class [view]]

Retransfer the given slave zone from the master 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 will be regenerated with all new signatures.

sign zone [class [view]]

Fetch 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, merge them 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 auto-dnssec zone option be set to allow or maintain, and also requires the zone to be configured to allow dynamic DNS. (See "Dynamic Update Policies" in the Administrator Reference Manual for more details.)

loadkeys zone [class [view]]

Fetch all DNSSEC keys for the given zone from the key directory. If they are within their publication period, merge them 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 auto-dnssec zone option be set to maintain, and also requires the zone to be configured to allow dynamic DNS. (See "Dynamic Update Policies" in the Administrator Reference Manual for more details.)

freeze [zone [class [view]]]

Suspend 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. It also causes changes in the journal file to be synced into the master file. All dynamic update attempts will be refused while the zone is frozen.

thaw [zone [class [view]]]

Enable 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 will no longer be refused. If the zone has changed and the ixfr-from-differences option is in use, then the journal file will be updated to reflect changes in the zone. Otherwise, if the zone has changed, any existing journal file will be removed.


Scan the list of available network interfaces for changes, without performing a full reconfig or waiting for the interface-interval timer.

sync [-clean] [zone [class [view]]]

Sync 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.

notify zone [class [view]]

Resend NOTIFY messages for the zone.


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

zonestatus [zone [class [view]]]

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.


Write server statistics to the statistics file.

querylog [on|off]

Enable or disable 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.

dumpdb [-all|-cache|-zone] [view ...]

Dump 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.

secroots [view ...]

Dump the server's security roots and negative trust anchors to the secroots file for the specified views. If no view is specified, all views are dumped.

stop [-p]

Stop 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 had completed stopping.

halt [-p]

Stop the server immediately. Recent changes made through dynamic update or IXFR are not saved to the master files, but will be 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 had completed halting.


Increment the servers debugging level by one.

trace level

Sets the server's debugging level to an explicit value.


Sets the server's debugging level to 0.


Flushes the server's cache.

flushname name [view]

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]

Flushes the given name, and all of its subdomains, from the view's DNS cache, address database, bad server cache, and SERVFAIL cache.


Display 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 not an explicit root zone configured.


Dump the list of queries named is currently recursing on.

validation ( on | off | check ) [view ...]

Enable, disable, or check the current status of DNSSEC validation. Note dnssec-enable also needs to be set to yes or auto to be effective. It defaults to enabled.

nta [( -d | -f | -r | -l duration)] domain [view]

Sets a DNSSEC negative trust anchor (NTA) for domain, with a lifetime of lifetime. The default lifetime is configured in <file>named.conf</file> via the nta-lifetime, and defaults to one hour. The lifetime cannot exceed one week.

A negative trust anchor selectively disables DNSSEC validation for zones that 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 will abort the DNSSEC validation process and treat the data as insecure rather than bogus. This continues until the NTA's lifetime is elapsed, or until the server is restarted (NTA's do not persist across restarts).

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 will be 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 will periodically test 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 will be allowed to expire early. The -force 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.

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


List the names of all TSIG keys currently configured for use by named in each view. The list both statically configured keys and dynamic TKEY-negotiated keys.

tsig-delete keyname [view]

Delete a given TKEY-negotiated key from the server. (This does not apply to statically configured TSIG keys.)

addzone zone [class [view]] configuration

Add 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 hash.nzf, where hash is a cryptographic hash generated from the name of the view. When named is restarted, the file will be loaded into the view configuration, so that zones that were added can persist after a restart.

This sample addzone command would add the zone to the default view:

$ rndc addzone '{ type master; file ""; };'

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

delzone [-clean] zone [class [view]]

Delete a zone while the server is running. Only zones that were originally added via rndc addzone can be deleted in this manner.

If the -clean is specified, the zone's master file (and journal file, if any) will be deleted along with the zone. Without the -clean option, zone files must be cleaned up by hand. (If the zone is of type "slave" or "stub", the files needing to be cleaned up will be reported in the output of the rndc delzone command.)

signing [( -list | -clear keyid/algorithm | -clear all | -nsec3param ( parameters | none ) ) ] zone [class [view]]

List, edit, or remove 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 will be 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 you wish to set the opt-out bit in the NSEC3 chain. 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.

So, for example, to create an NSEC3 chain using the SHA-1 hash algorithm, no opt-out flag, 10 iterations, and a salt value of "FFFF", use: rndc signing -nsec3param 1 0 10 FFFF zone. To set the opt-out flag, 15 iterations, and no salt, use: rndc signing -nsec3param 1 1 15 - zone.

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


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

Several error messages could be clearer.


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


Internet Systems Consortium

BIND Version 9.11