unbound Documentation

The source address to bind to for domain resolution and contacting the
   server on https.
   May be either an IPv4 address or IPv6 address (no brackets).

.. option:: -x

The pathname to the root-anchors.xml file on the server.
   (forms URL with :option:`-u`).
   The default is :file:`/root-anchors/root-anchors.xml`.

.. option:: -s

The pathname to the root-anchors.p7s file on the server.
   (forms URL with :option:`-u`).
   The default is :file:`/root-anchors/root-anchors.p7s`.
   This file has to be a PKCS7 signature over the xml file, using the pem
   file (:option:`-c`) as trust anchor.

.. option:: -n

The emailAddress for the Subject of the signer's certificate from the
   p7s signature file.
   Only signatures from this name are allowed.
   The default is ``[email protected]``.
   If you pass ``""`` then the emailAddress is not checked.

.. option:: -4

Use IPv4 for domain resolution and contacting the server on
   https.
   Default is to use IPv4 and IPv6 where appropriate.

.. option:: -6

Use IPv6 for domain resolution and contacting the server on https.
   Default is to use IPv4 and IPv6 where appropriate.

.. option:: -f <resolv.conf>

Use the given resolv.conf file.
   Not enabled by default, but you could try to pass
   :file:`/etc/resolv.conf` on some systems.
   It contains the IP addresses of the recursive nameservers to use.
   However, since this tool could be used to bootstrap that very recursive
   nameserver, it would not be useful (since that server is not up yet,
   since we are bootstrapping it).
   It could be useful in a situation where you know an upstream cache is
   deployed (and running) and in captive portal situations.

.. option:: -r <root.hints>

Use the given root.hints file (same syntax as the BIND and Unbound root
   hints file) to bootstrap domain resolution.
   By default a list of builtin root hints is used.
   unbound-anchor goes to the network itself for these roots, to resolve
   the server (:option:`-u` option) and to check the root DNSKEY records.
   It does so, because the tool when used for bootstrapping the recursive
   resolver, cannot use that recursive resolver itself because it is
   bootstrapping that server.

.. option:: -R

Allow fallback from :option:`-f` ``<resolv.conf>`` file to direct root
   servers query.
   It allows you to prefer local resolvers, but fallback automatically to
   direct root query if they do not respond or do not support DNSSEC.

.. option:: -v

More verbose.
   Once prints informational messages, multiple times may enable large
   debug amounts (such as full certificates or byte-dumps of downloaded
   files).
   By default it prints almost nothing.
   It also prints nothing on errors by default; in that case the original
   root anchor file is simply left undisturbed, so that a recursive server
   can start right after it.

.. option:: -C

Debug option to read :file:`` into the resolver process
   used.

.. option:: -P

Set the port number to use for the https connection.
   The default is 443.

.. option:: -F

Debug option to force update of the root anchor through downloading the
   xml file and verifying it with the certificate.
   By default it first tries to update by contacting the DNS, which uses
   much less bandwidth, is much faster (200 msec not 2 sec), and is nicer
   to the deployed infrastructure.
   With this option, it still attempts to do so (and may verbosely tell
   you), but then ignores the result and goes on to use the xml fallback
   method.

.. option:: -h

Show the version and commandline option help.

Exit Code Copy Chapter

This tool exits with value 1 if the root anchor was updated using the
certificate or if the builtin root-anchor was used.
It exits with code 0 if no update was necessary, if the update was possible
with :rfc:5011 tracking, or if an error occurred.

You can check the exit value in this manner:

.. code-block:: text

unbound-anchor -a "root.key" || logger "Please check root.key"

Or something more suitable for your operational environment.

Trust Copy Chapter

The root keys and update certificate included in this tool are provided for
convenience and under the terms of our license (see the LICENSE file in the
source distribution or https://github.com/NLnetLabs/unbound/blob/master/LICENSE
and might be stale or not suitable to your purpose.

By running :option:unbound-anchor -l the keys and certificate that are
configured in the code are printed for your convenience.

The built-in configuration can be overridden by providing a root-cert file and
a rootkey file.

Files Copy Chapter

@UNBOUND_ROOTKEY_FILE@
The root anchor file, updated with 5011 tracking, and read and written
to.
The file is created if it does not exist.

@UNBOUND_ROOTCERT_FILE@
The trusted self-signed certificate that is used to verify the
downloaded DNSSEC root trust anchor.
You can update it by fetching it from
https://data.iana.org/root-anchors/icannbundle.pem (and validate it).
If the file does not exist or is empty, a builtin version is used.

https://data.iana.org/root-anchors/root-anchors.xml
Source for the root key information.

https://data.iana.org/root-anchors/root-anchors.p7s
Signature on the root key information.

See Also Copy Chapter

:doc:unbound.conf(5)</manpages/unbound.conf>,
:doc:unbound(8)</manpages/unbound>.

Doc Unbound Checkconf (`doc/unbound-checkconf.rst`) Copy Section

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.. program:: unbound-checkconf

unbound-checkconf(8)

Synopsis Copy Chapter

unbound-checkconf [-ahf] [-o option] [cfgfile]

Description Copy Chapter

unbound-checkconf checks the configuration file for the
:doc:unbound(8)</manpages/unbound> DNS resolver for syntax and other errors.
The config file syntax is described in
:doc:unbound.conf(5)</manpages/unbound.conf>.

The available options are:

.. option:: -a

Also read the zonefiles for auth-zones and RPZ.
It checks if the syntax is okay of the zonefiles.

.. option:: -h

Show the version and commandline option help.

.. option:: -f

Print full pathname, with chroot applied to it.
Use with the :option:`-o` option.

.. option:: -q

Make the operation quiet, suppress output on success.

.. option:: -o

If given, after checking the config file the value of this option is
printed to stdout.
For ``""`` (disabled) options an empty line is printed.

.. option:: cfgfile

The config file to read with settings for Unbound.
It is checked.
If omitted, the config file at the default location is checked.

Exit Code Copy Chapter

The unbound-checkconf program exits with status code 1 on error, 0 for a
correct config file.

Files Copy Chapter

@ub_conf_file@
Unbound configuration file.

See Also Copy Chapter

:doc:unbound.conf(5)</manpages/unbound.conf>,
:doc:unbound(8)</manpages/unbound>.

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.. program:: unbound-control

unbound-control(8)

Synopsis Copy Chapter

unbound-control [-hq] [-c cfgfile] [-s server] command

Description Copy Chapter

unbound-control performs remote administration on the
:doc:unbound(8)</manpages/unbound> DNS server.
It reads the configuration file, contacts the Unbound server over TLS sends the
command and displays the result.

The available options are:

.. option:: -h

Show the version and commandline option help.

.. option:: -c

The config file to read with settings.
If not given the default config file
:file:`@ub_conf_file@` is used.

.. option:: -s <server[@port]>

IPv4 or IPv6 address of the server to contact.
If not given, the address is read from the config file.

.. option:: -q

Quiet, if the option is given it does not print anything if it works ok.

Commands Copy Chapter

There are several commands that the server understands.

@@[email protected]@start@@
Start the server.
Simply execs :doc:unbound(8)</manpages/unbound>.
The unbound executable is searched for in the PATH set in the
environment.
It is started with the config file specified using :option:-c or the
default config file.

@@[email protected]@stop@@
Stop the server.
The server daemon exits.

@@[email protected]@reload@@
Reload the server.
This flushes the cache and reads the config file fresh.

@@[email protected]@reload_keep_cache@@
Reload the server but try to keep the RRset and message cache if
(re)configuration allows for it.
That means the caches sizes and the number of threads must not change
between reloads.

@@[email protected]@fast_reload@@ [+dpv]
Reload the server, but keep downtime to a minimum, so that user queries
keep seeing service.
This needs the code compiled with threads.
The config is loaded in a thread, and prepared, then it briefly pauses the
existing server and updates config options.
The intent is that the pause does not impact the service of user queries.
The cache is kept.
Also user queries worked on are kept and continue, but with the new config
options.

.. note::
    This command is experimental at this time.

The amount of temporal memory needed during a fast_reload is twice the
amount needed for configuration.
This is because Unbound temporarily needs to store both current
configuration values and new ones while trying to fast_reload.
Zones loaded from disk (authority zones and RPZ zones) are included in such
memory needs.

Options that can be changed are for
:ref:`forwards`,
:ref:`stubs`,
:ref:`views`,
:ref:`authority zones`,
:ref:`RPZ zones` and
:ref:`local zones`.

Also
:ref:`access-control` and similar options,
:ref:`interface-action` and similar
options and
:ref:`tcp-connection-limit`.
It can reload some
:ref:`define-tag`
changes, more on that below.
Further options include
:ref:`insecure-lan-zones`,
:ref:`domain-insecure`,
:ref:`trust-anchor-file`,
:ref:`trust-anchor`,
:ref:`trusted-keys-file`,
:ref:`auto-trust-anchor-file`,
:ref:`edns-client-string`,
ipset,
:ref:`log-identity`,
:ref:`infra-cache-numhosts`,
:ref:`msg-cache-size`,
:ref:`rrset-cache-size`,
:ref:`key-cache-size`,
:ref:`ratelimit-size`,
:ref:`neg-cache-size`,
:ref:`num-queries-per-thread`,
:ref:`jostle-timeout`,
:ref:`use-caps-for-id`,
:ref:`unwanted-reply-threshold`,
:ref:`tls-use-sni`,
:ref:`outgoing-tcp-mss`,
:ref:`ip-dscp`,
:ref:`max-reuse-tcp-queries`,
:ref:`tcp-reuse-timeout`,
:ref:`tcp-auth-query-timeout`,
:ref:`delay-close`.
:ref:`iter-scrub-promiscuous`.
:ref:`tls-service-key`.
:ref:`tls-service-pem`.

It does not work with
:ref:`interface` and
:ref:`outgoing-interface` changes,
also not with
:ref:`remote control`,
:ref:`outgoing-port-permit`,
:ref:`outgoing-port-avoid`,
:ref:`msg-buffer-size`,
any **\*-slabs** options and
:ref:`statistics-interval` changes.

For :ref:`dnstap` these options can be changed:
:ref:`dnstap-log-resolver-query-messages`,
:ref:`dnstap-log-resolver-response-messages`,
:ref:`dnstap-log-client-query-messages`,
:ref:`dnstap-log-client-response-messages`,
:ref:`dnstap-log-forwarder-query-messages` and
:ref:`dnstap-log-forwarder-response-messages`.

It does not work with these options:
:ref:`dnstap-enable`,
:ref:`dnstap-bidirectional`,
:ref:`dnstap-socket-path`,
:ref:`dnstap-ip`,
:ref:`dnstap-tls`,
:ref:`dnstap-tls-server-name`,
:ref:`dnstap-tls-cert-bundle`,
:ref:`dnstap-tls-client-key-file` and
:ref:`dnstap-tls-client-cert-file`.

The options
:ref:`dnstap-send-identity`,
:ref:`dnstap-send-version`,
:ref:`dnstap-identity`, and
:ref:`dnstap-version` can be loaded
when ``+p`` is not used.

The ``+v`` option makes the output verbose which includes the time it took
to do the reload.
With ``+vv`` it is more verbose which includes the amount of memory that
was allocated temporarily to perform the reload; this amount of memory can
be big if the config has large contents.
In the timing output the 'reload' time is the time during which the server
was paused.

The ``+p`` option makes the reload not pause threads, they keep running.
Locks are acquired, but items are updated in sequence, so it is possible
for threads to see an inconsistent state with some options from the old
and some options from the new config, such as cache TTL parameters from the
old config and forwards from the new config.
The stubs and forwards are updated at the same time, so that they are
viewed consistently, either old or new values together.
The option makes the reload time take eg. 3 microseconds instead of 0.3
milliseconds during which the worker threads are interrupted.
So, the interruption is much shorter, at the expense of some inconsistency.
After the reload itself, every worker thread is briefly contacted to make
them release resources, this makes the delete timing a little longer, and
takes up time from the remote control servicing worker thread.

With the nopause option (``+p``), the reload does not work to reload some
options, that fast reload works on without the nopause option:
:ref:`val-bogus-ttl`,
:ref:`val-override-date`,
:ref:`val-sig-skew-min`,
:ref:`val-sig-skew-max`,
:ref:`val-max-restart`,
:ref:`val-nsec3-keysize-iterations`,
:ref:`target-fetch-policy`,
:ref:`outbound-msg-retry`,
:ref:`max-sent-count`,
:ref:`max-query-restarts`,
:ref:`do-not-query-address`,
:ref:`do-not-query-localhost`,
:ref:`private-address`,
:ref:`private-domain`,
:ref:`caps-exempt`,
:ref:`nat64-prefix`,
:ref:`do-nat64`,
:ref:`infra-host-ttl`,
:ref:`infra-keep-probing`,
:ref:`ratelimit`,
:ref:`ip-ratelimit`,
:ref:`ip-ratelimit-cookie`,
:ref:`wait-limit-netblock`,
:ref:`wait-limit-cookie-netblock`,
:ref:`ratelimit-below-domain`,
:ref:`ratelimit-for-domain`.

The ``+d`` option makes the reload drop queries that the worker threads are
working on.
This is like
:ref:`flush_requestlist`.
Without it the queries are kept so that users keep getting answers for
those queries that are currently processed.
The drop makes it so that queries during the life time of the
query processing see only old, or only new config options.

When there are changes to the config tags, from the
:ref:`define-tag` option,
then the ``+d`` option is implicitly turned on with a warning printout, and
queries are dropped.
This is to stop references to the old tag information, by the old
queries.
If the number of tags is increased in the newly loaded config, by
adding tags at the end, then the implicit ``+d`` option is not needed.

For response ip, that is actions associated with IP addresses, and perhaps
intersected with access control tag and action information, those settings
are stored with a query when it comes in based on its source IP address.
The old information is kept with the query until the queries are done.
This is gone when those queries are resolved and finished, or it is
possible to flush the requestlist with ``+d``.

@@[email protected]@verbosity@@ number
Change verbosity value for logging.
Same values as the verbosity: keyword in
:doc:unbound.conf(5)</manpages/unbound.conf>.
This new setting lasts until the server is issued a reload (taken from
config file again), or the next verbosity control command.

@@[email protected]@log_reopen@@
Reopen the logfile, close and open it.
Useful for logrotation to make the daemon release the file it is logging
to.
If you are using syslog it will attempt to close and open the syslog (which
may not work if chrooted).

@@[email protected]@stats@@
Print statistics.
Resets the internal counters to zero, this can be controlled using the
statistics-cumulative: config statement.
Statistics are printed with one [name]: [value] per line.

@@[email protected]@stats_noreset@@
Peek at statistics.
Prints them like the stats command does, but does not reset the internal
counters to zero.

@@[email protected]@status@@
Display server status.
Exit code 3 if not running (the connection to the port is refused), 1 on
error, 0 if running.

@@[email protected]@local_zone@@ name type
Add new local zone with name and type.
Like local-zone config statement.
If the zone already exists, the type is changed to the given argument.

@@[email protected]@local_zone_remove@@ name
Remove the local zone with the given name.
Removes all local data inside it.
If the zone does not exist, the command succeeds.

@@[email protected]@local_data@@ RR data...
Add new local data, the given resource record.
Like local-data: keyword, except for when no covering zone exists.
In that case this remote control command creates a transparent zone with
the same name as this record.

@@[email protected]@local_data_remove@@ name
Remove all RR data from local name.
If the name already has no items, nothing happens.
Often results in NXDOMAIN for the name (in a static zone), but if the name
has become an empty nonterminal (there is still data in domain names below
the removed name), NOERROR nodata answers are the result for that name.
With a specific RR instead of a domain name, that specific record is
removed from the local data, and not all the RR data.

@@[email protected]@local_zones@@
Add local zones read from stdin of unbound-control.
Input is read per line, with name space type on a line.
For bulk additions.

@@[email protected]@local_zones_remove@@
Remove local zones read from stdin of unbound-control.
Input is one name per line.
For bulk removals.

@@[email protected]@local_datas@@
Add local data RRs read from stdin of unbound-control.
Input is one RR per line.
For bulk additions.

@@[email protected]@local_datas_remove@@
Remove local data RRs read from stdin of unbound-control.
Input is one name per line.
For bulk removals.

@@[email protected]@dump_cache@@
The contents of the cache is printed in a text format to stdout.
You can redirect it to a file to store the cache in a file.
Not supported in remote Unbounds in multi-process operation.

@@[email protected]@load_cache@@
The contents of the cache is loaded from stdin.
Uses the same format as dump_cache uses.
Loading the cache with old, or wrong data can result in old or wrong data
returned to clients.
Loading data into the cache in this way is supported in order to aid with
debugging.
Not supported in remote Unbounds in multi-process operation.

@@[email protected]@cache_lookup@@ [+t] names
Print to stdout the RRsets and messages that are in the cache.
For every name listed the content at or under the name is printed.
Several names separated by spaces can be given, each is printed.
When subnetcache is enabled, also matching entries from the subnet
cache are printed.

The ``+t`` option allows tld and root names.
With it names like 'com' and '.' can be used, but it takes a lot of
effort to look up in the cache.

@@[email protected]@lookup@@ name
Print to stdout the name servers that would be used to look up the name
specified.

@@[email protected]@flush@@ [+c] name
Remove the name from the cache.
Removes the types A, AAAA, NS, SOA, CNAME, DNAME, MX, PTR, SRV, NAPTR,
SVCB and HTTPS.
Because that is fast to do.
Other record types can be removed using flush_type or flush_zone.

The ``+c`` option removes the items also from the cachedb cache.
If cachedb is in use.

@@[email protected]@flush_type@@ [+c] name type
Remove the name, type information from the cache.

The ``+c`` option removes the items also from the cachedb cache.
If cachedb is in use.

@@[email protected]@flush_zone@@ [+c] name
Remove all information at or below the name from the cache.
The rrsets and key entries are removed so that new lookups will be
performed.
This needs to walk and inspect the entire cache, and is a slow operation.
The entries are set to expired in the implementation of this command (so,
with serve-expired enabled, it'll serve that information but schedule a
prefetch for new information).

The ``+c`` option removes the items also from the cachedb cache.
If cachedb is in use.

@@[email protected]@flush_bogus@@ [+c]
Remove all bogus data from the cache.

The ``+c`` option removes the items also from the cachedb cache.
If cachedb is in use.

@@[email protected]@flush_negative@@ [+c]
Remove all negative data from the cache.
This is nxdomain answers, nodata answers and servfail answers.
Also removes bad key entries (which could be due to failed lookups) from
the dnssec key cache, and iterator last-resort lookup failures from the
rrset cache.

The ``+c`` option removes the items also from the cachedb cache.
If cachedb is in use.

@@[email protected]@flush_stats@@
Reset statistics to zero.

@@[email protected]@flush_requestlist@@
Drop the queries that are worked on.
Stops working on the queries that the server is working on now.
The cache is unaffected.
No reply is sent for those queries, probably making those users request
again later.
Useful to make the server restart working on queries with new settings,
such as a higher verbosity level.

@@[email protected]@dump_requestlist@@
Show what is worked on.
Prints all queries that the server is currently working on.
Prints the time that users have been waiting.
For internal requests, no time is printed.
And then prints out the module status.
This prints the queries from the first thread, and not queries that are
being serviced from other threads.

@@[email protected]@flush_infra@@ all|IP
If all then entire infra cache is emptied.
If a specific IP address, the entry for that address is removed from the
cache.
It contains EDNS, ping and lameness data.

@@[email protected]@dump_infra@@
Show the contents of the infra cache.

@@[email protected]@set_option@@ opt: val
Set the option to the given value without a reload.
The cache is therefore not flushed.
The option must end with a ':' and whitespace must be between the
option and the value.
Some values may not have an effect if set this way, the new values are not
written to the config file, not all options are supported.
This is different from the set_option call in libunbound, where all values
work because Unbound has not been initialized.

The values that work are: statistics-interval, statistics-cumulative,
do-not-query-localhost,  harden-short-bufsize, harden-large-queries,
harden-glue, harden-dnssec-stripped, harden-below-nxdomain,
harden-referral-path,  prefetch, prefetch-key, log-queries, hide-identity,
hide-version, identity, version, val-log-level, val-log-squelch,
ignore-cd-flag, add-holddown, del-holddown, keep-missing, tcp-upstream,
ssl-upstream, max-udp-size, ratelimit, ip-ratelimit, cache-max-ttl,
cache-min-ttl, cache-max-negative-ttl.

@@[email protected]@get_option@@ opt
Get the value of the option.
Give the option name without a trailing ':'.
The value is printed.
If the value is "", nothing is printed and the connection closes.
On error 'error ...' is printed (it gives a syntax error on unknown
option).
For some options a list of values, one on each line, is printed.
The options are shown from the config file as modified with set_option.
For some options an override may have been taken that does not show up with
this command, not results from e.g. the verbosity and forward control
commands.
Not all options work, see list_stubs, list_forwards, list_local_zones and
list_local_data for those.

@@[email protected]@list_stubs@@
List the stub zones in use.
These are printed one by one to the output.
This includes the root hints in use.

@@[email protected]@list_forwards@@
List the forward zones in use.
These are printed zone by zone to the output.

@@[email protected]@list_insecure@@
List the zones with domain-insecure.

@@[email protected]@list_local_zones@@
List the local zones in use.
These are printed one per line with zone type.

@@[email protected]@list_local_data@@
List the local data RRs in use.
The resource records are printed.

@@[email protected]@insecure_add@@ zone
Add a domain-insecure for the given zone, like the statement in
unbound.conf.
Adds to the running Unbound without affecting the cache
contents (which may still be bogus, use flush_zone to remove it), does not
affect the config file.

@@[email protected]@insecure_remove@@ zone
Removes domain-insecure for the given zone.

@@[email protected]@forward_add@@ [+it] zone addr ...
Add a new forward zone to running Unbound.
With +i option also adds a domain-insecure for the zone (so it can
resolve insecurely if you have a DNSSEC root trust anchor configured for
other names).
The addr can be IP4, IP6 or nameserver names, like forward-zone config in
unbound.conf.
The +t option sets it to use TLS upstream, like
:ref:forward-tls-upstream: yes.

@@[email protected]@forward_remove@@ [+i] zone
Remove a forward zone from running Unbound.
The +i also removes a domain-insecure for the zone.

@@[email protected]@stub_add@@ [+ipt] zone addr ...
Add a new stub zone to running Unbound.
With +i option also adds a domain-insecure for the zone.
With +p the stub zone is set to prime, without it it is set to
notprime.
The addr can be IP4, IP6 or nameserver names, like the stub-zone:
config in unbound.conf.
The +t option sets it to use TLS upstream, like
:ref:stub-tls-upstream: yes.

@@[email protected]@stub_remove@@ [+i] zone
Remove a stub zone from running Unbound.
The +i also removes a domain-insecure for the zone.

@@[email protected]@forward@@ [off | addr ... ]
Setup forwarding mode.
Configures if the server should ask other upstream nameservers, should go
to the internet root nameservers itself, or show the current config.
You could pass the nameservers after a DHCP update.

Without arguments the current list of addresses used to forward all queries
to is printed.
On startup this is from the forward-zone ``"."`` configuration.
Afterwards it shows the status.
It prints off when no forwarding is used.

If off is passed, forwarding is disabled and the root nameservers are
used.
This can be used to avoid to avoid buggy or non-DNSSEC supporting
nameservers returned from DHCP.
But may not work in hotels or hotspots.

If one or more IPv4 or IPv6 addresses are given, those are then used to
forward queries to.
The addresses must be separated with spaces.
With ``'@port'`` the port number can be set explicitly (default port is 53
(DNS)).

By default the forwarder information from the config file for the root
``"."`` is used.
The config file is not changed, so after a reload these changes are gone.
Other forward zones from the config file are not affected by this command.

@@[email protected]@ratelimit_list@@ [+a]
List the domains that are ratelimited.
Printed one per line with current estimated qps and qps limit from config.
With +a it prints all domains, not just the ratelimited domains, with
their estimated qps.
The ratelimited domains return an error for uncached (new) queries, but
cached queries work as normal.

@@[email protected]@ip_ratelimit_list@@ [+a]
List the ip addresses that are ratelimited.
Printed one per line with current estimated qps and qps limit from config.
With +a it prints all ips, not just the ratelimited ips, with their
estimated qps.
The ratelimited ips are dropped before checking the cache.

@@[email protected]@list_auth_zones@@
List the auth zones that are configured.
Printed one per line with a status, indicating if the zone is expired and
current serial number.
Configured RPZ zones are included.

@@[email protected]@auth_zone_reload@@ zone
Reload the auth zone (or RPZ zone) from zonefile.
The zonefile is read in overwriting the current contents of the zone in
memory.
This changes the auth zone contents itself, not the cache contents.
Such cache contents exists if you set Unbound to validate with
for-upstream: yes and that can be cleared with flush_zone zone.

@@[email protected]@auth_zone_transfer@@ zone
Transfer the auth zone (or RPZ zone) from master.
The auth zone probe sequence is started, where the masters are probed to
see if they have an updated zone (with the SOA serial check).
And then the zone is transferred for a newer zone version.

@@[email protected]@rpz_enable@@ zone
Enable the RPZ zone if it had previously been disabled.

@@[email protected]@rpz_disable@@ zone
Disable the RPZ zone.

@@[email protected]@view_list_local_zones@@ view
list_local_zones for given view.

@@[email protected]@view_local_zone@@ view name type
local_zone for given view.

@@[email protected]@view_local_zone_remove@@ view name
local_zone_remove for given view.

@@[email protected]@view_list_local_data@@ view
list_local_data for given view.

@@[email protected]@view_local_data@@ view RR data...
local_data for given view.

@@[email protected]@view_local_data_remove@@ view name
local_data_remove for given view.

@@[email protected]@view_local_datas_remove@@ view
Remove a list of local_data for given view from stdin.
Like local_datas_remove.

@@[email protected]@view_local_datas@@ view
Add a list of local_data for given view from stdin.
Like local_datas.

@@[email protected]@add_cookie_secret@@ secret
Add or replace a cookie secret persistently.
secret needs to be an 128 bit hex string.

Cookie secrets can be either **active** or **staging**.
**Active** cookie secrets are used to create DNS Cookies, but verification
of a DNS Cookie succeeds with any of the **active** or **staging** cookie
secrets.
The state of the current cookie secrets can be printed with the
:ref:`print_cookie_secrets`
command.

When there are no cookie secrets configured yet, the *secret* is added as
**active**.
If there is already an **active** cookie secret, the *secret* is added as
**staging** or replacing an existing **staging** secret.

To "roll" a cookie secret used in an anycast set.
The new secret has to be added as **staging** secret to **all** nodes in
the anycast set.
When **all** nodes can verify DNS Cookies with the new secret, the new
secret can be activated with the
:ref:`activate_cookie_secret`
command.
After **all** nodes have the new secret **active** for at least one hour,
the previous secret can be dropped with the
:ref:`drop_cookie_secret`
command.

Persistence is accomplished by writing to a file which is configured with
the
:ref:`cookie-secret-file`
option in the server section of the config file.
This is disabled by default, "".

@@[email protected]@drop_cookie_secret@@
Drop the staging cookie secret.

@@[email protected]@activate_cookie_secret@@
Make the current staging cookie secret active, and the current
active cookie secret staging.

@@[email protected]@print_cookie_secrets@@
Show the current configured cookie secrets with their status.

Exit Code Copy Chapter

The unbound-control program exits with status code 1 on error, 0 on
success.

Set Up Copy Chapter

The setup requires a self-signed certificate and private keys for both the
server and client.
The script unbound-control-setup generates these in the default run
directory, or with -d in another directory.
If you change the access control permissions on the key files you can decide
who can use unbound-control, by default owner and group but not all users.
Run the script under the same username as you have configured in
:file:unbound.conf or as root, so that the daemon is permitted to read the
files, for example with:

.. code-block:: bash

sudo -u unbound unbound-control-setup

If you have not configured a username in :file:unbound.conf, the keys need
read permission for the user credentials under which the daemon is started.
The script preserves private keys present in the directory.
After running the script as root, turn on
:ref:control-enable in
:file:unbound.conf.

Statistic Counters Copy Chapter

The :ref:stats and
:ref:stats_noreset commands show a
number of statistic counters:

@@[email protected]@threadX.num.queries@@
number of queries received by thread

@@[email protected]@threadX.num.queries_ip_ratelimited@@
number of queries rate limited by thread

@@[email protected]@threadX.num.queries_cookie_valid@@
number of queries with a valid DNS Cookie by thread

@@[email protected]@threadX.num.queries_cookie_client@@
number of queries with a client part only DNS Cookie by thread

@@[email protected]@threadX.num.queries_cookie_invalid@@
number of queries with an invalid DNS Cookie by thread

@@[email protected]@threadX.num.queries_discard_timeout@@
number of queries removed due to discard-timeout by thread

@@[email protected]@threadX.num.queries_replyaddr_limit@@
number of queries removed due to replyaddr limits by thread

@@[email protected]@threadX.num.queries_wait_limit@@
number of queries removed due to wait-limit by thread

@@[email protected]@threadX.num.cachehits@@
number of queries that were successfully answered using a cache lookup

@@[email protected]@threadX.num.cachemiss@@
number of queries that needed recursive processing

@@[email protected]@threadX.num.dnscrypt.crypted@@
number of queries that were encrypted and successfully decapsulated by
dnscrypt.

@@[email protected]@threadX.num.dnscrypt.cert@@
number of queries that were requesting dnscrypt certificates.

@@[email protected]@threadX.num.dnscrypt.cleartext@@
number of queries received on dnscrypt port that were cleartext and not a
request for certificates.

@@[email protected]@threadX.num.dnscrypt.malformed@@
number of request that were neither cleartext, not valid dnscrypt messages.

@@[email protected]@threadX.num.dns_error_reports@@
number of DNS Error Reports generated by thread

@@[email protected]@threadX.num.prefetch@@
number of cache prefetches performed.
This number is included in cachehits, as the original query had the
unprefetched answer from cache, and resulted in recursive processing,
taking a slot in the requestlist.
Not part of the recursivereplies (or the histogram thereof) or cachemiss,
as a cache response was sent.

@@[email protected]@threadX.num.expired@@
number of replies that served an expired cache entry.

@@[email protected]@threadX.num.queries_timed_out@@
number of queries that are dropped because they waited in the UDP socket
buffer for too long.

@@[email protected]@threadX.query.queue_time_us.max@@
The maximum wait time for packets in the socket buffer, in microseconds.
This is only reported when
:ref:sock-queue-timeout is enabled.

@@[email protected]@threadX.num.recursivereplies@@
The number of replies sent to queries that needed recursive processing.
Could be smaller than threadX.num.cachemiss if due to timeouts no replies
were sent for some queries.

@@[email protected]@threadX.requestlist.avg@@
The average number of requests in the internal recursive processing request
list on insert of a new incoming recursive processing query.

@@[email protected]@threadX.requestlist.max@@
Maximum size attained by the internal recursive processing request list.

@@[email protected]@threadX.requestlist.overwritten@@
Number of requests in the request list that were overwritten by newer
entries.
This happens if there is a flood of queries that recursive processing and
the server has a hard time.
The counter is increased when during the flood the
:ref:jostle-timeout
allows a query to be removed in favor of a new incoming query.
The older query is then dropped to make space.

@@[email protected]@threadX.requestlist.exceeded@@
Queries that were dropped because the request list was full.
This happens if a flood of queries need recursive processing, and the
server can not keep up.
The counter is increased when during the flood there is no space
to be made with the jostle out of an older query, and the new query
is dropped.
Since no older queries are removed, see
:ref:jostle-timeout setting, there
is no space for the new query.

@@[email protected]@threadX.requestlist.current.all@@
Current size of the request list, includes internally generated queries
(such as priming queries and glue lookups).

@@[email protected]@threadX.requestlist.current.user@@
Current size of the request list, only the requests from client queries.

@@[email protected]@threadX.requestlist.current.replies@@
Current count of the number of reply entries waiting on request list
entries. Because a request list entry can send results to multiple reply
addresses, this number may be larger than the size of the request list.

@@[email protected]@threadX.recursion.time.avg@@
Average time it took to answer queries that needed recursive processing.
Note that queries that were answered from the cache are not in this average.

@@[email protected]@threadX.recursion.time.median@@
The median of the time it took to answer queries that needed recursive
processing.
The median means that 50% of the user queries were answered in less than
this time.
Because of big outliers (usually queries to non responsive servers), the
average can be bigger than the median.
This median has been calculated by interpolation from a histogram.

@@[email protected]@threadX.tcpusage@@
The currently held tcp buffers for incoming connections.
A spot value on the time of the request.
This helps you spot if the incoming-num-tcp buffers are full.

@@[email protected]@total.num.queries@@
summed over threads.

@@[email protected]@total.num.queries_ip_ratelimited@@
summed over threads.

@@[email protected]@total.num.queries_cookie_valid@@
summed over threads.

@@[email protected]@total.num.queries_cookie_client@@
summed over threads.

@@[email protected]@total.num.queries_cookie_invalid@@
summed over threads.

@@[email protected]@total.num.queries_discard_timeout@@
summed over threads.

@@[email protected]@total.num.queries_replyaddr_limit@@
summed over threads.

@@[email protected]@total.num.queries_wait_limit@@
summed over threads.

@@[email protected]@total.num.cachehits@@
summed over threads.

@@[email protected]@total.num.cachemiss@@
summed over threads.

@@[email protected]@total.num.dnscrypt.crypted@@
summed over threads.

@@[email protected]@total.num.dnscrypt.cert@@
summed over threads.

@@[email protected]@total.num.dnscrypt.cleartext@@
summed over threads.

@@[email protected]@total.num.dnscrypt.malformed@@
summed over threads.

@@[email protected]@total.num.dns_error_reports@@
summed over threads.

@@[email protected]@total.num.prefetch@@
summed over threads.

@@[email protected]@total.num.expired@@
summed over threads.

@@[email protected]@total.num.queries_timed_out@@
summed over threads.

@@[email protected]@total.query.queue_time_us.max@@
the maximum of the thread values.

@@[email protected]@total.num.recursivereplies@@
summed over threads.

@@[email protected]@total.requestlist.avg@@
averaged over threads.

@@[email protected]@total.requestlist.max@@
the maximum of the thread requestlist.max values.

@@[email protected]@total.requestlist.overwritten@@
summed over threads.

@@[email protected]@total.requestlist.exceeded@@
summed over threads.

@@[email protected]@total.requestlist.current.all@@
summed over threads.

@@[email protected]@total.requestlist.current.user@@
summed over threads.

@@[email protected]@total.requestlist.current.replies@@
summed over threads.

@@[email protected]@total.recursion.time.median@@
averaged over threads.

@@[email protected]@total.tcpusage@@
summed over threads.

@@[email protected]@time.now@@
current time in seconds since 1970.

@@[email protected]@time.up@@
uptime since server boot in seconds.

@@[email protected]@time.elapsed@@
time since last statistics printout, in seconds.

Extended Statistics Copy Chapter

@@[email protected]@mem.cache.rrset@@
Memory in bytes in use by the RRset cache.

@@[email protected]@mem.cache.message@@
Memory in bytes in use by the message cache.

@@[email protected]@mem.cache.dnscrypt_shared_secret@@
Memory in bytes in use by the dnscrypt shared secrets cache.

@@[email protected]@mem.cache.dnscrypt_nonce@@
Memory in bytes in use by the dnscrypt nonce cache.

@@[email protected]@mem.mod.iterator@@
Memory in bytes in use by the iterator module.

@@[email protected]@mem.mod.validator@@
Memory in bytes in use by the validator module.
Includes the key cache and negative cache.

@@[email protected]@mem.streamwait@@
Memory in bytes in used by the TCP and TLS stream wait buffers.
These are answers waiting to be written back to the clients.

@@[email protected]@mem.http.query_buffer@@
Memory in bytes used by the HTTP/2 query buffers.
Containing (partial) DNS queries waiting for request stream completion.

@@[email protected]@mem.http.response_buffer@@
Memory in bytes used by the HTTP/2 response buffers.
Containing DNS responses waiting to be written back to the clients.

@@[email protected]@mem.quic@@
Memory in bytes used by QUIC.
Containing connection information, stream information, queries read and
responses written back to the clients.

@@[email protected]@histogram@@...to..
Shows a histogram, summed over all threads.
Every element counts the recursive queries whose reply time fit between the
lower and upper bound.
Times larger or equal to the lowerbound, and smaller than the upper bound.
There are 40 buckets, with bucket sizes doubling.

@@[email protected]@num.query.type.A@@
The total number of queries over all threads with query type A.
Printed for the other query types as well, but only for the types for which
queries were received, thus =0 entries are omitted for brevity.

@@[email protected]@num.query.type.other@@
Number of queries with query types 256-65535.

@@[email protected]@num.query.class.IN@@
The total number of queries over all threads with query class IN
(internet).
Also printed for other classes (such as CH (CHAOS) sometimes used for
debugging), or NONE, ANY, used by dynamic update.
num.query.class.other is printed for classes 256-65535.

@@[email protected]@num.query.opcode.QUERY@@
The total number of queries over all threads with query opcode QUERY.
Also printed for other opcodes, UPDATE, ...

@@[email protected]@num.query.tcp@@
Number of queries that were made using TCP towards the Unbound server.

@@[email protected]@num.query.tcpout@@
Number of queries that the Unbound server made using TCP outgoing towards
other servers.

@@[email protected]@num.query.udpout@@
Number of queries that the Unbound server made using UDP outgoing towards
other servers.

@@[email protected]@num.query.tls@@
Number of queries that were made using TLS towards the Unbound server.
These are also counted in num.query.tcp, because TLS uses TCP.

@@[email protected]@num.query.tls.resume@@
Number of TLS session resumptions, these are queries over TLS towards the
Unbound server where the client negotiated a TLS session resumption key.

@@[email protected]@num.query.https@@
Number of queries that were made using HTTPS towards the Unbound server.
These are also counted in num.query.tcp and num.query.tls, because HTTPS
uses TLS and TCP.

@@[email protected]@num.query.quic@@
Number of queries that were made using QUIC towards the Unbound server.
These are also counted in num.query.tls, because TLS is used for these
queries.

@@[email protected]@num.query.ipv6@@
Number of queries that were made using IPv6 towards the Unbound server.

@@[email protected]@num.query.flags.RD@@
The number of queries that had the RD flag set in the header.
Also printed for flags QR, AA, TC, RA, Z, AD, CD.
Note that queries with flags QR, AA or TC may have been rejected because of
that.

@@[email protected]@num.query.edns.present@@
number of queries that had an EDNS OPT record present.

@@[email protected]@num.query.edns.DO@@
number of queries that had an EDNS OPT record with the DO (DNSSEC OK) bit
set.
These queries are also included in the num.query.edns.present number.

@@[email protected]@num.query.ratelimited@@
The number of queries that are turned away from being send to nameserver
due to ratelimiting.

@@[email protected]@num.query.dnscrypt.shared_secret.cachemiss@@
The number of dnscrypt queries that did not find a shared secret in the
cache.
This can be use to compute the shared secret hitrate.

@@[email protected]@num.query.dnscrypt.replay@@
The number of dnscrypt queries that found a nonce hit in the nonce cache
and hence are considered a query replay.

@@[email protected]@num.answer.rcode.NXDOMAIN@@
The number of answers to queries, from cache or from recursion, that had
the return code NXDOMAIN.
Also printed for the other return codes.

@@[email protected]@num.answer.rcode.nodata@@
The number of answers to queries that had the pseudo return code nodata.
This means the actual return code was NOERROR, but additionally, no data
was carried in the answer (making what is called a NOERROR/NODATA answer).
These queries are also included in the num.answer.rcode.NOERROR number.
Common for AAAA lookups when an A record exists, and no AAAA.

@@[email protected]@num.answer.secure@@
Number of answers that were secure.
The answer validated correctly.
The AD bit might have been set in some of these answers, where the client
signalled (with DO or AD bit in the query) that they were ready to accept
the AD bit in the answer.

@@[email protected]@num.answer.bogus@@
Number of answers that were bogus.
These answers resulted in SERVFAIL to the client because the answer failed
validation.

@@[email protected]@num.rrset.bogus@@
The number of rrsets marked bogus by the validator.
Increased for every RRset inspection that fails.

@@[email protected]@num.valops@@
The number of validation operations performed by the validator.
Increased for every RRSIG verification operation regardless of the
validation result.
The RRSIG and key combination needs to first pass some sanity checks before
Unbound even performs the verification, e.g., length/protocol checks.

@@[email protected]@unwanted.queries@@
Number of queries that were refused or dropped because they failed the
access control settings.

@@[email protected]@unwanted.replies@@
Replies that were unwanted or unsolicited.
Could have been random traffic, delayed duplicates, very late answers, or
could be spoofing attempts.
Some low level of late answers and delayed duplicates are to be expected
with the UDP protocol.
Very high values could indicate a threat (spoofing).

@@[email protected]@msg.cache.count@@
The number of items (DNS replies) in the message cache.

@@[email protected]@rrset.cache.count@@
The number of RRsets in the rrset cache.
This includes rrsets used by the messages in the message cache, but also
delegation information.

@@[email protected]@infra.cache.count@@
The number of items in the infra cache.
These are IP addresses with their timing and protocol support information.

@@[email protected]@key.cache.count@@
The number of items in the key cache.
These are DNSSEC keys, one item per delegation point, and their validation
status.

@@[email protected]@msg.cache.max_collisions@@
The maximum number of hash table collisions in the msg cache.
This is the number of hashes that are identical when a new element is
inserted in the hash table.
If the value is very large, like hundreds, something is wrong with the
performance of the hash table, hash values are incorrect or malicious.

@@[email protected]@rrset.cache.max_collisions@@
The maximum number of hash table collisions in the rrset cache.
This is the number of hashes that are identical when a new element is
inserted in the hash table.
If the value is very large, like hundreds, something is wrong with the
performance of the hash table, hash values are incorrect or malicious.

@@[email protected]@dnscrypt_shared_secret.cache.count@@
The number of items in the shared secret cache.
These are precomputed shared secrets for a given client public key/server
secret key pair.
Shared secrets are CPU intensive and this cache allows Unbound to avoid
recomputing the shared secret when multiple dnscrypt queries are sent from
the same client.

@@[email protected]@dnscrypt_nonce.cache.count@@
The number of items in the client nonce cache.
This cache is used to prevent dnscrypt queries replay.
The client nonce must be unique for each client public key/server secret
key pair.
This cache should be able to host QPS * replay window interval keys to
prevent replay of a query during replay window seconds.

@@[email protected]@num.query.authzone.up@@
The number of queries answered from auth-zone data, upstream queries.
These queries would otherwise have been sent (with fallback enabled) to the
internet, but are now answered from the auth zone.

@@[email protected]@num.query.authzone.down@@
The number of queries for downstream answered from auth-zone data.
These queries are from downstream clients, and have had an answer from the
data in the auth zone.

@@[email protected]@num.query.aggressive.NOERROR@@
The number of queries answered using cached NSEC records with NODATA RCODE.
These queries would otherwise have been sent to the internet, but are now
answered using cached data.

@@[email protected]@num.query.aggressive.NXDOMAIN@@
The number of queries answered using cached NSEC records with NXDOMAIN
RCODE.
These queries would otherwise have been sent to the internet, but are now
answered using cached data.

@@[email protected]@num.query.subnet@@
Number of queries that got an answer that contained EDNS client subnet
data.

@@[email protected]@num.query.subnet_cache@@
Number of queries answered from the edns client subnet cache.
These are counted as cachemiss by the main counters, but hit the client
subnet specific cache after getting processed by the edns client subnet
module.

@@[email protected]@num.query.cachedb@@
Number of queries answered from the external cache of cachedb.
These are counted as cachemiss by the main counters, but hit the cachedb
external cache after getting processed by the cachedb module.

@@[email protected]@num.rpz.action@@.
Number of queries answered using configured RPZ policy, per RPZ action
type.
Possible actions are: nxdomain, nodata, passthru, drop, tcp-only,
local-data, disabled, and cname-override.

Files Copy Chapter

@ub_conf_file@
Unbound configuration file.

@UNBOUND_RUN_DIR@
directory with private keys (:file:unbound_server.key and
:file:unbound_control.key) and self-signed certificates
(:file:unbound_server.pem and :file:unbound_control.pem).

See Also Copy Chapter

:doc:unbound.conf(5)</manpages/unbound.conf>,
:doc:unbound(8)</manpages/unbound>.

Doc Unbound Host (`doc/unbound-host.rst`) Copy Section

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

.. program:: unbound-host

unbound-host(1)

Synopsis Copy Chapter

unbound-host [-C configfile] [-vdhr46D] [-c class]
[-t type] [-y key] [-f keyfile] [-F namedkeyfile] hostname

Description Copy Chapter

unbound-host uses the Unbound validating resolver to query for the hostname
and display results.
With the :option:-v option it displays validation status: secure, insecure,
bogus (security failure).

By default it reads no configuration file whatsoever.
It attempts to reach the internet root servers.
With :option:-C an unbound config file and with :option:-r resolv.conf
can be read.

The available options are:

.. option:: hostname

This name is resolved (looked up in the DNS).
   If a IPv4 or IPv6 address is given, a reverse lookup is performed.

.. option:: -h

Show the version and commandline option help.

.. option:: -v

Enable verbose output and it shows validation results, on every line.
   Secure means that the NXDOMAIN (no such domain name), nodata (no such
   data) or positive data response validated correctly with one of the
   keys.
   Insecure means that that domain name has no security set up for it.
   Bogus (security failure) means that the response failed one or more
   checks, it is likely wrong, outdated, tampered with, or broken.

.. option:: -d

Enable debug output to stderr.
   One :option:`-d` shows what the resolver and validator are doing and may
   tell you what is going on.
   More times, :option:`-d` :option:`-d`, gives a lot of output, with every
   packet sent and received.

.. option:: -c

Specify the class to lookup for, the default is IN the internet
   class.

.. option:: -t

Specify the type of data to lookup.
   The default looks for IPv4, IPv6 and mail handler data, or domain name
   pointers for reverse queries.

.. option:: -y

Specify a public key to use as trust anchor.
   This is the base for a chain of trust that is built up from the trust
   anchor to the response, in order to validate the response message.
   Can be given as a DS or DNSKEY record.
   For example:

   .. code-block:: text

        -y "example.com DS 31560 5 1 1CFED84787E6E19CCF9372C1187325972FE546CD"

.. option:: -D

Enables DNSSEC validation.
   Reads the root anchor from the default configured root anchor at the
   default location, :file:`@UNBOUND_ROOTKEY_FILE@`.

.. option:: -f

Reads keys from a file.
   Every line has a DS or DNSKEY record, in the format as for :option:`-y`.
   The zone file format, the same as ``dig`` and ``drill`` produce.

.. option:: -F

Reads keys from a BIND-style :file:`named.conf` file.
   Only the ``trusted-key {};`` entries are read.

.. option:: -C

Uses the specified unbound.conf to prime :doc:`libunbound(3)</manpages/libunbound>`.
   Pass it as first argument if you want to override some options from the
   config file with further arguments on the commandline.

.. option:: -r

Read :file:`/etc/resolv.conf`, and use the forward DNS servers from
   there (those could have been set by DHCP).
   More info in *resolv.conf(5)*.
   Breaks validation if those servers do not support DNSSEC.

.. option:: -4

Use solely the IPv4 network for sending packets.

.. option:: -6

Use solely the IPv6 network for sending packets.

Examples Copy Chapter

Some examples of use.
The keys shown below are fakes, thus a security failure is encountered.

.. code-block:: text

$ unbound-host www.example.com

   $ unbound-host -v -y "example.com DS 31560 5 1 1CFED84787E6E19CCF9372C1187325972FE546CD" www.example.com

   $ unbound-host -v -y "example.com DS 31560 5 1 1CFED84787E6E19CCF9372C1187325972FE546CD" 192.0.2.153

Exit Code Copy Chapter

The unbound-host program exits with status code 1 on error, 0 on no error.
The data may not be available on exit code 0, exit code 1 means the lookup
encountered a fatal error.

See Also Copy Chapter

:doc:unbound.conf(5)</manpages/unbound.conf>,
:doc:unbound(8)</manpages/unbound>.

Doc Unbound.Conf (`doc/unbound.conf.rst`) Copy Section

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

..
WHEN EDITING MAKE SURE EACH SENTENCE STARTS ON A NEW LINE

..
IT HELPS RENDERERS TO DO THE RIGHT THING WRT SPACE

..
IT HELPS PEOPLE DIFFING THE CHANGES

unbound.conf(5)

Synopsis Copy Chapter

unbound.conf

Description Copy Chapter

unbound.conf is used to configure :doc:unbound(8)</manpages/unbound>.

The utility :doc:unbound-checkconf(8)</manpages/unbound-checkconf> can be
used to check unbound.conf prior to usage.

File Format Copy Chapter

Whitespace is used to separate keywords.
Whitespace indentation is insignificant, but is still recommended for visual
clarity.
Comments start with # and last to the end of line.
Empty lines are ignored, as is whitespace at the beginning of a line.

Attribute keywords end with a colon (:) and they are either options or
section clauses (group options together).

The configuration file is logically divided into sections where each section
is introduced by a :ref:section clause.

Example Copy Chapter

An example minimal config file is shown below; most settings are the defaults.
Copy this to @ub_conf_file@ and start the server with:

.. code-block:: text

$ unbound -c @ub_conf_file@

Stop the server with:

.. code-block:: text

$ kill `cat @UNBOUND_PIDFILE@`

The source distribution contains an extensive :file:example.conf file with
all the options.

.. code-block:: text

# unbound.conf(5) config file for unbound(8).
server:
    directory: "@UNBOUND_RUN_DIR@"
    username: unbound
    # make sure unbound can access entropy from inside the chroot.
    # e.g. on linux the use these commands (on BSD, devfs(8) is used):
    #      mount --bind -n /dev/urandom @UNBOUND_RUN_DIR@/dev/urandom
    # and  mount --bind -n /dev/log @UNBOUND_RUN_DIR@/dev/log
    chroot: "@UNBOUND_CHROOT_DIR@"
    # logfile: "@UNBOUND_RUN_DIR@/unbound.log"  #uncomment to use logfile.
    pidfile: "@UNBOUND_PIDFILE@"
    # verbosity: 1      # uncomment and increase to get more logging.
    # listen on all interfaces, answer queries from the local subnet.
    interface: 0.0.0.0
    interface: ::0
    access-control: 10.0.0.0/8 allow
    access-control: 2001:db8::/64 allow

.. _unbound.conf.clauses:

Section Clauses Copy Chapter

The recognized section clauses are:

:ref:`server:`
    Most of the configuration is found in this section.

:ref:`remote-control:`
    Configuration for the facility used by
    :doc:`unbound-control(8)</manpages/unbound-control>`.

:ref:`stub-zone:`
    Configuration for a zone that redirects to specific authoritative name
    servers, e.g. for zones not generally available on the greater
    Internet.

:ref:`forward-zone:`
    Configuration for a zone that forwards to specific DNS resolvers.

:ref:`auth-zone:`
    Configuration for local authoritative zones.

:ref:`view:`
    Overriding a small subset of configuration for incoming requests.
    Requests are mapped to views with
    :ref:`access-control-view` and
    :ref:`interface-view`.

:ref:`python:`
    Configuration for the optional ``python`` script module.

:ref:`dynlib:`
    Configuration for the optional ``dynlib`` module that loads dynamic
    libraries into Unbound.

:ref:`dnscrypt:`
    Configuration for the optional DNSCrypt feature.

:ref:`cachedb:`
    Configuration for the optional ``cachedb`` module that can interface
    with second level caches, currently Redis or Redis-complatible
    databases.

:ref:`dnstap:`
    Configuration of the optional dnstap logging feature; a flexible,
    structured binary log format for DNS software.

:ref:`rpz:`
    Configuration for Response Policy Zones that allows for DNS filtering.
    Requires the ``respip`` module.

Section clauses can be repeated throughout the file (or included files) to
logically group options in one visually cohesive group.
This may be particularly useful for the server: clause with its myriad of
options.

.. _unbound.conf.include:

Including Files Copy Chapter

Files can be included using the include: directive.
It can appear anywhere, it accepts a single file name as argument.
Processing continues as if the text from the included file was copied into the
config file at that point.
If also using :ref:chroot, using full path names for
the included files works, relative pathnames for the included names work if the
directory where the daemon is started equals its chroot/working directory or is
specified before the include statement with :ref:directory: dir.
Wildcards can be used to include multiple files, see glob(7).

.. _unbound.conf.include-toplevel:

For a more structural include option, the include-toplevel: directive can
be used.
This closes whatever section clause is currently active (if any) and forces the
use of section clauses in the included files and right after this directive.

.. _unbound.conf.server:

Server Options Copy Chapter

These options are part of the server: section.

@@[email protected]@verbosity@@:
The verbosity level.

Level 0
    No verbosity, only errors.

Level 1
    Gives operational information.

Level 2
    Gives detailed operational information including short information per
    query.

Level 3
    Gives query level information, output per query.

Level 4
    Gives algorithm level information.

Level 5
    Logs client identification for cache misses.

The verbosity can also be increased from the command line and during run
time via remote control. See :doc:`unbound(8)</manpages/unbound>` and
:doc:`unbound-control(8)</manpages/unbound-control>` respectively.

Default: 1

@@[email protected]@statistics-interval@@:
The number of seconds between printing statistics to the log for every
thread.
Disable with value 0 or "".
The histogram statistics are only printed if replies were sent during the
statistics interval, requestlist statistics are printed for every interval
(but can be 0).
This is because the median calculation requires data to be present.

Default: 0 (disabled)

@@[email protected]@statistics-cumulative@@:
If enabled, statistics are cumulative since starting Unbound, without
clearing the statistics counters after logging the statistics.

Default: no

@@[email protected]@extended-statistics@@:
If enabled, extended statistics are printed from
:doc:unbound-control(8)</manpages/unbound-control>.
The counters are listed in
:doc:unbound-control(8)</manpages/unbound-control>.
Keeping track of more statistics takes time.

Default: no

@@[email protected]@statistics-inhibit-zero@@:
If enabled, selected extended statistics with a value of 0 are inhibited
from printing with
:doc:unbound-control(8)</manpages/unbound-control>.
These are query types, query classes, query opcodes, answer rcodes
(except NOERROR, FORMERR, SERVFAIL, NXDOMAIN, NOTIMPL, REFUSED)
and PRZ actions.

Default: yes

@@[email protected]@num-threads@@:
The number of threads to create to serve clients. Use 1 for no threading.

Default: 1

@@[email protected]@port@@: **
The port number on which the server responds to queries.

Default: 53

@@[email protected]@interface@@: **
Interface to use to connect to the network.
This interface is listened to for queries from clients, and answers to
clients are given from it.
Can be given multiple times to work on several interfaces.
If none are given the default is to listen on localhost.

If an interface name is used instead of an IP address, the list of IP
addresses on that interface are used.
The interfaces are not changed on a reload (``kill -HUP``) but only on
restart.

A port number can be specified with @port (without spaces between interface
and port number), if not specified the default port (from
:ref:`port`) is used.

@@[email protected]@ip-address@@: **
Same as :ref:interface (for ease of
compatibility with :external+nsd:doc:manpages/nsd.conf).

@@[email protected]@interface-automatic@@:
Listen on all addresses on all (current and future) interfaces, detect the
source interface on UDP queries and copy them to replies.
This is a lot like :ref:ip-transparent, but
this option services all interfaces whilst with
:ref:ip-transparent you can select which
(future) interfaces Unbound provides service on.
This feature is experimental, and needs support in your OS for particular
socket options.

Default: no

@@[email protected]@interface-automatic-ports@@: ""
List the port numbers that
:ref:interface-automatic listens on.
If empty, the default port is listened on.
The port numbers are separated by spaces in the string.

This can be used to have interface automatic to deal with the interface,
and listen on the normal port number, by including it in the list, and
also HTTPS or DNS-over-TLS port numbers by putting them in the list as
well.

Default: ""

@@[email protected]@outgoing-interface@@: **
Interface to use to connect to the network.
This interface is used to send queries to authoritative servers and receive
their replies.
Can be given multiple times to work on several interfaces.
If none are given the default (all) is used.
You can specify the same interfaces in
:ref:interface and
:ref:outgoing-interface lines, the
interfaces are then used for both purposes.
Outgoing queries are sent via a random outgoing interface to counter
spoofing.

If an IPv6 netblock is specified instead of an individual IPv6 address,
outgoing UDP queries will use a randomised source address taken from the
netblock to counter spoofing.
Requires the IPv6 netblock to be routed to the host running Unbound, and
requires OS support for unprivileged non-local binds (currently only
supported on Linux).
Several netblocks may be specified with multiple
:ref:`outgoing-interface` options, but do
not specify both an individual IPv6 address and an IPv6 netblock, or the
randomisation will be compromised.
Consider combining with :ref:`prefer-ip6: yes` to
increase the likelihood of IPv6 nameservers being selected for queries.
On Linux you need these two commands to be able to use the freebind socket
option to receive traffic for the ip6 netblock:

.. code-block:: text

    ip -6 addr add mynetblock/64 dev lo && \
    ip -6 route add local mynetblock/64 dev lo

@@[email protected]@outgoing-range@@:
Number of ports to open.
This number of file descriptors can be opened per thread.
Must be at least 1.
Default depends on compile options.
Larger numbers need extra resources from the operating system.
For performance a very large value is best, use libevent to make this
possible.
Should be higher (preferably double) than the value of
:ref:num-queries-per-thread to
account for cases where the request list is full and avoid file descriptor
starvation.

Default: 4096 (libevent) / 960 (minievent) / 48 (windows)

@@[email protected]@outgoing-port-permit@@: **
Permit Unbound to open this port or range of ports for use to send queries.
A larger number of permitted outgoing ports increases resilience against
spoofing attempts.
Make sure these ports are not needed by other daemons.
By default only ports above 1024 that have not been assigned by IANA are
used.
Give a port number or a range of the form "low-high", without spaces.

The :ref:`outgoing-port-permit` and
:ref:`outgoing-port-avoid` statements
are processed in the line order of the config file, adding the permitted
ports and subtracting the avoided ports from the set of allowed ports.
The processing starts with the non IANA allocated ports above 1024 in the
set of allowed ports.

@@[email protected]@outgoing-port-avoid@@: **
Do not permit Unbound to open this port or range of ports for use to send
queries.
Use this to make sure Unbound does not grab a port that another daemon
needs.
The port is avoided on all outgoing interfaces, both IPv4 and IPv6.
By default only ports above 1024 that have not been assigned by IANA are
used.
Give a port number or a range of the form "low-high", without spaces.

@@[email protected]@outgoing-num-tcp@@:
Number of outgoing TCP buffers to allocate per thread.
If set to 0, or if :ref:do-tcp: no is set, no TCP
queries to authoritative servers are done.
For larger installations increasing this value is a good idea.

Default: 10

@@[email protected]@incoming-num-tcp@@:
Number of incoming TCP buffers to allocate per thread.
If set to 0, or if :ref:do-tcp: no is set, no TCP
queries from clients are accepted.
For larger installations increasing this value is a good idea.

Default: 10

@@[email protected]@edns-buffer-size@@:
Number of bytes size to advertise as the EDNS reassembly buffer size.
This is the value put into datagrams over UDP towards peers.
The actual buffer size is determined by
:ref:msg-buffer-size (both for TCP and
UDP).
Do not set higher than that value.
Setting to 512 bypasses even the most stringent path MTU problems, but is
seen as extreme, since the amount of TCP fallback generated is excessive
(probably also for this resolver, consider tuning
:ref:outgoing-num-tcp).

Default: 1232 (`DNS Flag Day 2020 recommendation
<https://dnsflagday.net/2020/>`__)

@@[email protected]@max-udp-size@@:
Maximum UDP response size (not applied to TCP response).
65536 disables the UDP response size maximum, and uses the choice from the
client, always.
Suggested values are 512 to 4096.

Default: 1232 (same as :ref:`edns-buffer-size`)

@@[email protected]@stream-wait-size@@:
Number of bytes size maximum to use for waiting stream buffers.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).
As TCP and TLS streams queue up multiple results, the amount of memory used
for these buffers does not exceed this number, otherwise the responses are
dropped.
This manages the total memory usage of the server (under heavy use), the
number of requests that can be queued up per connection is also limited,
with further requests waiting in TCP buffers.

Default: 4m

@@[email protected]@msg-buffer-size@@:
Number of bytes size of the message buffers.
Default is 65552 bytes, enough for 64 Kb packets, the maximum DNS message
size.
No message larger than this can be sent or received.
Can be reduced to use less memory, but some requests for DNS data, such as
for huge resource records, will result in a SERVFAIL reply to the client.

Default: 65552

@@[email protected]@msg-cache-size@@:
Number of bytes size of the message cache.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).

Default: 4m

@@[email protected]@msg-cache-slabs@@:
Number of slabs in the message cache.
Slabs reduce lock contention by threads.
Must be set to a power of 2.
Setting (close) to the number of cpus is a fairly good setting.
If left unconfigured, it will be configured automatically to be a power of
2 close to the number of configured threads in multi-threaded environments.

Default: (unconfigured)

@@[email protected]@num-queries-per-thread@@:
The number of queries that every thread will service simultaneously.
If more queries arrive that need servicing, and no queries can be jostled
out (see :ref:jostle-timeout), then the
queries are dropped.
This forces the client to resend after a timeout; allowing the server time
to work on the existing queries.
Default depends on compile options.

Default: 2048 (libevent) / 512 (minievent) / 24 (windows)

@@[email protected]@jostle-timeout@@:
Timeout used when the server is very busy.
Set to a value that usually results in one roundtrip to the authority
servers.

If too many queries arrive, then 50% of the queries are allowed to run to
completion, and the other 50% are replaced with the new incoming query if
they have already spent more than their allowed time.
This protects against denial of service by slow queries or high query
rates.

The effect is that the qps for long-lasting queries is about:

.. code-block:: text

    (num-queries-per-thread / 2) / (average time for such long queries) qps

The qps for short queries can be about:

.. code-block:: text

    (num-queries-per-thread / 2) / (jostle-timeout in whole seconds) qps per thread

about (2048/2)*5 = 5120 qps by default.

Default: 200

@@[email protected]@delay-close@@:
Extra delay for timeouted UDP ports before they are closed, in msec.
This prevents very delayed answer packets from the upstream (recursive)
servers from bouncing against closed ports and setting off all sort of
close-port counters, with eg. 1500 msec.
When timeouts happen you need extra sockets, it checks the ID and remote IP
of packets, and unwanted packets are added to the unwanted packet counter.

Default: 0 (disabled)

@@[email protected]@udp-connect@@:
Perform connect(2) for UDP sockets that mitigates ICMP side channel
leakage.

Default: yes

@@[email protected]@unknown-server-time-limit@@:
The wait time in msec for waiting for an unknown server to reply.
Increase this if you are behind a slow satellite link, to eg. 1128.
That would then avoid re-querying every initial query because it times out.

Default: 376

@@[email protected]@discard-timeout@@:
The wait time in msec where recursion requests are dropped.
This is to stop a large number of replies from accumulating.
They receive no reply, the work item continues to recurse.
For UDP the replies are dropped, for stream connections the reply
is not dropped if the stream connection is still open ready to receive
answers.
It is nice to be a bit larger than
:ref:serve-expired-client-timeout
if that is enabled.
A value of 1900 msec is suggested.
The value 0 disables it.

Default: 1900

@@[email protected]@wait-limit@@:
The number of replies that can wait for recursion, for an IP address.
This makes a ratelimit per IP address of waiting replies for recursion.
It stops very large amounts of queries waiting to be returned to one
destination.
The value 0 disables all wait limits.

Default: 1000

@@[email protected]@wait-limit-cookie@@:
The number of replies that can wait for recursion, for an IP address
that sent the query with a valid DNS Cookie.
Since the cookie already validates the client address, this option allows
to override a configured
:ref:wait-limit value usually with a higher one
for cookie validated queries.
The value 0 disables wait limits for cookie validated queries.

Default: 10000

@@[email protected]@wait-limit-netblock@@:
The wait limit for the netblock.
If not given the
:ref:wait-limit
value is used.
The most specific netblock is used to determine the limit.
Useful for overriding the default for a specific, group or individual,
server.
The value -1 disables wait limits for the netblock.
By default the loopback has a wait limit netblock of -1, it is not
limited, because it is separated from the rest of network for spoofed
packets.
The loopback addresses 127.0.0.0/8 and ::1/128 are default at -1.

Default: (none)

@@[email protected]@wait-limit-cookie-netblock@@:
The wait limit for the netblock, when the query has a DNS Cookie.
If not given, the
:ref:wait-limit-cookie
value is used.
The value -1 disables wait limits for the netblock.
The loopback addresses 127.0.0.0/8 and ::1/128 are default at -1.

Default: (none)

@@[email protected]@so-rcvbuf@@:
If not 0, then set the SO_RCVBUF socket option to get more buffer space on
UDP port 53 incoming queries.
So that short spikes on busy servers do not drop packets (see counter in
netstat -su).
Otherwise, the number of bytes to ask for, try "4m" on a busy server.

The OS caps it at a maximum, on linux Unbound needs root permission to
bypass the limit, or the admin can use ``sysctl net.core.rmem_max``.

On BSD change ``kern.ipc.maxsockbuf`` in ``/etc/sysctl.conf``.

On OpenBSD change header and recompile kernel.

On Solaris ``ndd -set /dev/udp udp_max_buf 8388608``.

Default: 0 (use system value)

@@[email protected]@so-sndbuf@@:
If not 0, then set the SO_SNDBUF socket option to get more buffer space on
UDP port 53 outgoing responses.
This for very busy servers handles spikes in answer traffic, otherwise:

.. code-block:: text

    send: resource temporarily unavailable

can get logged, the buffer overrun is also visible by ``netstat -su``.
If set to 0 it uses the system value.
Specify the number of bytes to ask for, try "8m" on a very busy server.

It needs some space to be able to deal with packets that wait for local
address resolution, from like ARP and NDP discovery, before they are sent
out, hence it is elevated above the system default by default.

The OS caps it at a maximum, on linux Unbound needs root permission to
bypass the limit, or the admin can use ``sysctl net.core.wmem_max``.

On BSD, Solaris changes are similar to
:ref:`so-rcvbuf`.

Default: 4m

@@[email protected]@so-reuseport@@:
If yes, then open dedicated listening sockets for incoming queries for each
thread and try to set the SO_REUSEPORT socket option on each socket.
May distribute incoming queries to threads more evenly.

On Linux it is supported in kernels >= 3.9.

On other systems, FreeBSD, OSX it may also work.

You can enable it (on any platform and kernel), it then attempts to open
the port and passes the option if it was available at compile time, if that
works it is used, if it fails, it continues silently (unless verbosity 3)
without the option.

At extreme load it could be better to turn it off to distribute the queries
evenly, reported for Linux systems (4.4.x).

Default: yes

@@[email protected]@ip-transparent@@:
If yes, then use IP_TRANSPARENT socket option on sockets where Unbound is
listening for incoming traffic.
Allows you to bind to non-local interfaces.
For example for non-existent IP addresses that are going to exist later on,
with host failover configuration.

This is a lot like
:ref:`interface-automatic`, but that one
services all interfaces and with this option you can select which (future)
interfaces Unbound provides service on.

This option needs Unbound to be started with root permissions on some
systems.
The option uses IP_BINDANY on FreeBSD systems and SO_BINDANY on OpenBSD
systems.

Default: no

@@[email protected]@ip-freebind@@:
If yes, then use IP_FREEBIND socket option on sockets where Unbound is
listening to incoming traffic.
Allows you to bind to IP addresses that are nonlocal or do not exist, like
when the network interface or IP address is down.

Exists only on Linux, where the similar
:ref:`ip-transparent` option is also
available.

Default: no

@@[email protected]@ip-dscp@@:
The value of the Differentiated Services Codepoint (DSCP) in the
differentiated services field (DS) of the outgoing IP packet headers.
The field replaces the outdated IPv4 Type-Of-Service field and the IPv6
traffic class field.

@@[email protected]@rrset-cache-size@@:
Number of bytes size of the RRset cache.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).

Default: 4m

@@[email protected]@rrset-cache-slabs@@:
Number of slabs in the RRset cache.
Slabs reduce lock contention by threads.
Must be set to a power of 2.
Setting (close) to the number of cpus is a fairly good setting.
If left unconfigured, it will be configured automatically to be a power of
2 close to the number of configured threads in multi-threaded environments.

Default: (unconfigured)

@@[email protected]@cache-max-ttl@@:
Time to live maximum for RRsets and messages in the cache.
When the TTL expires, the cache item has expired.
Can be set lower to force the resolver to query for data often, and not
trust (very large) TTL values.
Downstream clients also see the lower TTL.

Default: 86400 (1 day)

@@[email protected]@cache-min-ttl@@:
Time to live minimum for RRsets and messages in the cache.
If the minimum kicks in, the data is cached for longer than the domain
owner intended, and thus less queries are made to look up the data.
Zero makes sure the data in the cache is as the domain owner intended,
higher values, especially more than an hour or so, can lead to trouble as
the data in the cache does not match up with the actual data any more.

Default: 0 (disabled)

@@[email protected]@cache-max-negative-ttl@@:
Time to live maximum for negative responses, these have a SOA in the
authority section that is limited in time.
This applies to NXDOMAIN and NODATA answers.

Default: 3600

@@[email protected]@cache-min-negative-ttl@@:
Time to live minimum for negative responses, these have a SOA in the
authority section that is limited in time.
If this is disabled and
:ref:cache-min-ttl
is configured, it will take effect instead.
In that case you can set this to 1 to honor the upstream TTL.
This applies to NXDOMAIN and NODATA answers.

Default: 0 (disabled)

@@[email protected]@infra-host-ttl@@:
Time to live for entries in the host cache.
The host cache contains roundtrip timing, lameness and EDNS support
information.

Default: 900

@@[email protected]@infra-cache-slabs@@:
Number of slabs in the infrastructure cache.
Slabs reduce lock contention by threads.
Must be set to a power of 2.
Setting (close) to the number of cpus is a fairly good setting.
If left unconfigured, it will be configured automatically to be a power of
2 close to the number of configured threads in multi-threaded environments.

Default: (unconfigured)

@@[email protected]@infra-cache-numhosts@@:
Number of hosts for which information is cached.

Default: 10000

@@[email protected]@infra-cache-min-rtt@@:
Lower limit for dynamic retransmit timeout calculation in infrastructure
cache.
Increase this value if using forwarders needing more time to do recursive
name resolution.

Default: 50

@@[email protected]@infra-cache-max-rtt@@:
Upper limit for dynamic retransmit timeout calculation in infrastructure
cache.

Default: 120000 (2 minutes)

@@[email protected]@infra-keep-probing@@:
If enabled the server keeps probing hosts that are down, in the one probe
at a time regime.
Hosts that are down, eg. they did not respond during the one probe at a
time period, are marked as down and it may take
:ref:infra-host-ttl time to get probed
again.

Default: no

@@[email protected]@define-tag@@: ""
Define the tags that can be used with
:ref:local-zone and
:ref:access-control.
Enclose the list between quotes ("") and put spaces between tags.

@@[email protected]@do-ip4@@:
Enable or disable whether IPv4 queries are answered or issued.

Default: yes

@@[email protected]@do-ip6@@:
Enable or disable whether IPv6 queries are answered or issued.
If disabled, queries are not answered on IPv6, and queries are not sent on
IPv6 to the internet nameservers.
With this option you can disable the IPv6 transport for sending DNS
traffic, it does not impact the contents of the DNS traffic, which may have
IPv4 (A) and IPv6 (AAAA) addresses in it.

Default: yes

@@[email protected]@prefer-ip4@@:
If enabled, prefer IPv4 transport for sending DNS queries to internet
nameservers.
Useful if the IPv6 netblock the server has, the entire /64 of that is not
owned by one operator and the reputation of the netblock /64 is an issue,
using IPv4 then uses the IPv4 filters that the upstream servers have.

Default: no

@@[email protected]@prefer-ip6@@:
If enabled, prefer IPv6 transport for sending DNS queries to internet
nameservers.

Default: no

@@[email protected]@do-udp@@:
Enable or disable whether UDP queries are answered or issued.

Default: yes

@@[email protected]@do-tcp@@:
Enable or disable whether TCP queries are answered or issued.

Default: yes

@@[email protected]@tcp-mss@@:
Maximum segment size (MSS) of TCP socket on which the server responds to
queries.
Value lower than common MSS on Ethernet (1220 for example) will address
path MTU problem.
Note that not all platform supports socket option to set MSS (TCP_MAXSEG).
Default is system default MSS determined by interface MTU and negotiation
between server and client.

@@[email protected]@outgoing-tcp-mss@@:
Maximum segment size (MSS) of TCP socket for outgoing queries (from Unbound
to other servers).
Value lower than common MSS on Ethernet (1220 for example) will address
path MTU problem.
Note that not all platform supports socket option to set MSS (TCP_MAXSEG).
Default is system default MSS determined by interface MTU and negotiation
between Unbound and other servers.

@@[email protected]@tcp-idle-timeout@@:
The period Unbound will wait for a query on a TCP connection.
If this timeout expires Unbound closes the connection.
When the number of free incoming TCP buffers falls below 50% of the total
number configured, the option value used is progressively reduced, first to
1% of the configured value, then to 0.2% of the configured value if the
number of free buffers falls below 35% of the total number configured, and
finally to 0 if the number of free buffers falls below 20% of the total
number configured.
A minimum timeout of 200 milliseconds is observed regardless of the option
value used.
It will be overridden by
:ref:edns-tcp-keepalive-timeout
if
:ref:edns-tcp-keepalive
is enabled.

Default: 30000 (30 seconds)

@@[email protected]@tcp-reuse-timeout@@:
The period Unbound will keep TCP persistent connections open to authority
servers.

Default: 60000 (60 seconds)

@@[email protected]@max-reuse-tcp-queries@@:
The maximum number of queries that can be sent on a persistent TCP
connection.

Default: 200

@@[email protected]@tcp-auth-query-timeout@@:
Timeout in milliseconds for TCP queries to auth servers.

Default: 3000 (3 seconds)

@@[email protected]@edns-tcp-keepalive@@:
Enable or disable EDNS TCP Keepalive.

Default: no

@@[email protected]@edns-tcp-keepalive-timeout@@:
Overrides
:ref:tcp-idle-timeout
when
:ref:edns-tcp-keepalive
is enabled.
If the client supports the EDNS TCP Keepalive option,
If the client supports the EDNS TCP Keepalive option, Unbound sends the
timeout value to the client to encourage it to close the connection before
the server times out.

Default: 120000 (2 minutes)

@@[email protected]@sock-queue-timeout@@:
UDP queries that have waited in the socket buffer for a long time can be
dropped.
The time is set in seconds, 3 could be a good value to ignore old queries
that likely the client does not need a reply for any more.
This could happen if the host has not been able to service the queries for
a while, i.e. Unbound is not running, and then is enabled again.
It uses timestamp socket options.
The socket option is available on the Linux and FreeBSD platforms.

Default: 0 (disabled)

@@[email protected]@tcp-upstream@@:
Enable or disable whether the upstream queries use TCP only for transport.
Useful in tunneling scenarios.
If set to no you can specify TCP transport only for selected forward or
stub zones using
:ref:forward-tcp-upstream or
:ref:stub-tcp-upstream
respectively.

Default: no

@@[email protected]@udp-upstream-without-downstream@@:
Enable UDP upstream even if :ref:do-udp: no is set.
Useful for TLS service providers, that want no UDP downstream but use UDP
to fetch data upstream.

Default: no (no changes)

@@[email protected]@tls-upstream@@:
Enabled or disable whether the upstream queries use TLS only for transport.
Useful in tunneling scenarios.
The TLS contains plain DNS in TCP wireformat.
The other server must support this (see
:ref:tls-service-key).

If you enable this, also configure a
:ref:`tls-cert-bundle` or use
:ref:`tls-win-cert` or
:ref:`tls-system-cert` to load CA certs,
otherwise the connections cannot be authenticated.

This option enables TLS for all of them, but if you do not set this you can
configure TLS specifically for some forward zones with
:ref:`forward-tls-upstream`.
And also with
:ref:`stub-tls-upstream`.
If the
:ref:`tls-upstream`
option is enabled, it is for all the forwards and stubs, where the
:ref:`forward-tls-upstream`
and
:ref:`stub-tls-upstream`
options are ignored, as if they had been set to yes.

Default: no

@@[email protected]@ssl-upstream@@:
Alternate syntax for :ref:tls-upstream.
If both are present in the config file the last is used.

@@[email protected]@tls-service-key@@:
If enabled, the server provides DNS-over-TLS or DNS-over-HTTPS service on
the TCP ports marked implicitly or explicitly for these services with
:ref:tls-port or
:ref:https-port.
The file must contain the private key for the TLS session, the public
certificate is in the :ref:tls-service-pem
file and it must also be specified if
:ref:tls-service-key is specified.
If the key is stored with root permissions or outside of chroot, then
a change or enabling or disabling requires a restart (a reload is not
enough).
But if the key file (and tls-service-pem file) are accessible, then they
are read in on reload, and fast_reload.
The server checks the modification time of the file (and the filename)
to see if the file has changed for reload.
The ports enabled implicitly or explicitly via
:ref:tls-port and
:ref:https-port do not provide normal DNS TCP
service.

.. note::
    Unbound needs to be compiled with libnghttp2 in order to provide
    DNS-over-HTTPS.

Default: "" (disabled)

@@[email protected]@ssl-service-key@@:
Alternate syntax for :ref:tls-service-key.

@@[email protected]@tls-service-pem@@:
The public key certificate pem file for the tls service.

Default: "" (disabled)

@@[email protected]@ssl-service-pem@@:
Alternate syntax for :ref:tls-service-pem.

@@[email protected]@tls-port@@:
The port number on which to provide TCP TLS service.
Only interfaces configured with that port number as @number get the TLS
service.

Default: 853

@@[email protected]@ssl-port@@:
Alternate syntax for :ref:tls-port.

@@[email protected]@tls-cert-bundle@@:
If null or "", no file is used.
Set it to the certificate bundle file, for example
:file:/etc/pki/tls/certs/ca-bundle.crt.
These certificates are used for authenticating connections made to outside
peers.
For example :ref:auth-zone urls, and also
DNS-over-TLS connections.
It is read at start up before permission drop and chroot.

Default: "" (disabled)

@@[email protected]@ssl-cert-bundle@@:
Alternate syntax for :ref:tls-cert-bundle.

@@[email protected]@tls-win-cert@@:
Add the system certificates to the cert bundle certificates for
authentication.
If no cert bundle, it uses only these certificates.
On windows this option uses the certificates from the cert store.
Use the :ref:tls-cert-bundle option on
other systems.
On other systems, this option enables the system certificates.

Default: no

@@[email protected]@tls-system-cert@@:
This the same as the
:ref:tls-win-cert option, under a
different name.
Because it is not windows specific.

@@[email protected]@tls-additional-port@@: **
List port numbers as
:ref:tls-additional-port, and when
interfaces are defined, eg. with the @port suffix, as this port number,
they provide DNS-over-TLS service.
Can list multiple, each on a new statement.

@@[email protected]@tls-session-ticket-keys@@:
If not "", lists files with 80 bytes of random contents that are used
to perform TLS session resumption for clients using the Unbound server.
These files contain the secret key for the TLS session tickets.
First key use to encrypt and decrypt TLS session tickets.
Other keys use to decrypt only.

With this you can roll over to new keys, by generating a new first file and
allowing decrypt of the old file by listing it after the first file for
some time, after the wait clients are not using the old key any more and
the old key can be removed.
One way to create the file is:

.. code-block:: text

    dd if=/dev/random bs=1 count=80 of=ticket.dat

The first 16 bytes should be different from the old one if you create a
second key, that is the name used to identify the key.
Then there is 32 bytes random data for an AES key and then 32 bytes random
data for the HMAC key.

Default: ""

@@[email protected]@tls-ciphers@@:
Set the list of ciphers to allow when serving TLS.
Use "" for default ciphers.

Default: ""

@@[email protected]@tls-ciphersuites@@:
Set the list of ciphersuites to allow when serving TLS.
This is for newer TLS 1.3 connections.
Use "" for default ciphersuites.

Default: ""

@@[email protected]@tls-use-sni@@:
Enable or disable sending the SNI extension on TLS connections.

.. note:: Changing the value requires a restart.

Default: yes

@@[email protected]@tls-protocols@@: ""
Specify the allowed TLS protocol versions to use, in no particular order.
Possible values are TLSv1.2 and TLSv1.3.
Enclose list of protocols in quotes ("") and put spaces between them.

.. note:: Changing the value requires a restart.

Default: "TLSv1.2 TLSv1.3"

@@[email protected]@pad-responses@@:
If enabled, TLS serviced queries that contained an EDNS Padding option will
cause responses padded to the closest multiple of the size specified in
:ref:pad-responses-block-size.

Default: yes

@@[email protected]@pad-responses-block-size@@:
The block size with which to pad responses serviced over TLS.
Only responses to padded queries will be padded.

Default: 468

@@[email protected]@pad-queries@@:
If enabled, all queries sent over TLS upstreams will be padded to the
closest multiple of the size specified in
:ref:pad-queries-block-size.

Default: yes

@@[email protected]@pad-queries-block-size@@:
The block size with which to pad queries sent over TLS upstreams.

Default: 128

@@[email protected]@https-port@@:
The port number on which to provide DNS-over-HTTPS service.
Only interfaces configured with that port number as @number get the HTTPS
service.

Default: 443

@@[email protected]@http-endpoint@@:
The HTTP endpoint to provide DNS-over-HTTPS service on.

Default: /dns-query

@@[email protected]@http-max-streams@@:
Number used in the SETTINGS_MAX_CONCURRENT_STREAMS parameter in the HTTP/2
SETTINGS frame for DNS-over-HTTPS connections.

Default: 100

@@[email protected]@http-query-buffer-size@@:
Maximum number of bytes used for all HTTP/2 query buffers combined.
These buffers contain (partial) DNS queries waiting for request stream
completion.
An RST_STREAM frame will be send to streams exceeding this limit.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).

Default: 4m

@@[email protected]@http-response-buffer-size@@:
Maximum number of bytes used for all HTTP/2 response buffers combined.
These buffers contain DNS responses waiting to be written back to the
clients.
An RST_STREAM frame will be send to streams exceeding this limit.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).

Default: 4m

@@[email protected]@http-nodelay@@:
Set TCP_NODELAY socket option on sockets used to provide DNS-over-HTTPS
service.
Ignored if the option is not available.

Default: yes

@@[email protected]@http-notls-downstream@@:
Disable use of TLS for the downstream DNS-over-HTTP connections.
Useful for local back end servers.

Default: no

@@[email protected]@proxy-protocol-port@@: **
List port numbers as
:ref:proxy-protocol-port, and when
interfaces are defined, eg. with the @port suffix, as this port number,
they support and expect PROXYv2.

In this case the proxy address will only be used for the network
communication and initial ACL (check if the proxy itself is denied/refused
by configuration).

The proxied address (if any) will then be used as the true client address
and will be used where applicable for logging, ACL, DNSTAP, RPZ and IP
ratelimiting.

PROXYv2 is supported for UDP and TCP/TLS listening interfaces.

There is no support for PROXYv2 on a DoH, DoQ or DNSCrypt listening interface.

Can list multiple, each on a new statement.

@@[email protected]@quic-port@@:
The port number on which to provide DNS-over-QUIC service.
Only interfaces configured with that port number as @number get the QUIC
service.
The interface uses QUIC for the UDP traffic on that port number.
If it is set to 0, the server does not init QUIC code, and QUIC is
disabled.
This is similar to if QUIC is not in use, but then explicitly.

Default: 853

@@[email protected]@quic-size@@:
Maximum number of bytes for all QUIC buffers and data combined.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).
New connections receive connection refused when the limit is exceeded.
New streams are reset when the limit is exceeded.

Default: 8m

@@[email protected]@use-systemd@@:
Enable or disable systemd socket activation.

Default: no

@@[email protected]@do-daemonize@@:
Enable or disable whether the Unbound server forks into the background as a
daemon.
Set the value to no when Unbound runs as systemd service.

Default: yes

@@[email protected]@tcp-connection-limit@@: * *
Allow up to limit simultaneous TCP connections from the given netblock.
When at the limit, further connections are accepted but closed immediately.
This option is experimental at this time.

Default: (disabled)

@@[email protected]@access-control@@: * *
Specify treatment of incoming queries from their originating IP address.
Queries can be allowed to have access to this server that gives DNS
answers, or refused, with other actions possible.
The IP address range can be specified as a netblock, it is possible to give
the statement several times in order to specify the treatment of different
netblocks.
The netblock is given as an IPv4 or IPv6 address with /size appended for a
classless network block.
The most specific netblock match is used, if none match
:ref:refuse is used.
The order of the access-control statements therefore does not matter.
The action can be
:ref:deny,
:ref:refuse,
:ref:allow,
:ref:allow_setrd,
:ref:allow_snoop,
:ref:allow_cookie,
:ref:deny_non_local or
:ref:refuse_non_local.

@@[email protected]@deny@@
    Stops queries from hosts from that netblock.

@@[email protected]@refuse@@
    Stops queries too, but sends a DNS rcode REFUSED error message back.

@@[email protected]@allow@@
    Gives access to clients from that netblock.
    It gives only access for recursion clients (which is what almost all
    clients need).
    Non-recursive queries are refused.

    The :ref:`allow` action does
    allow non-recursive queries to access the local-data that is
    configured.
    The reason is that this does not involve the Unbound server recursive
    lookup algorithm, and static data is served in the reply.
    This supports normal operations where non-recursive queries are made
    for the authoritative data.
    For non-recursive queries any replies from the dynamic cache are
    refused.

@@[email protected]@allow_setrd@@
    Ignores the recursion desired (RD) bit and treats all requests as if
    the recursion desired bit is set.

    Note that this behavior violates :rfc:`1034` which states that a name
    server should never perform recursive service unless asked via the RD
    bit since this interferes with trouble shooting of name servers and
    their databases.
    This prohibited behavior may be useful if another DNS server must
    forward requests for specific zones to a resolver DNS server, but only
    supports stub domains and sends queries to the resolver DNS server with
    the RD bit cleared.

@@[email protected]@allow_snoop@@
    Gives non-recursive access too.
    This gives both recursive and non recursive access.
    The name *allow_snoop* refers to cache snooping, a technique to use
    non-recursive queries to examine the cache contents (for malicious
    acts).
    However, non-recursive queries can also be a valuable debugging tool
    (when you want to examine the cache contents).

    In that case use
    :ref:`allow_snoop` for
    your administration host.

@@[email protected]@allow_cookie@@
    Allows access only to UDP queries that contain a valid DNS Cookie as
    specified in RFC 7873 and RFC 9018, when the
    :ref:`answer-cookie` option is enabled.
    UDP queries containing only a DNS Client Cookie and no Server Cookie,
    or an invalid DNS Cookie, will receive a BADCOOKIE response including a
    newly generated DNS Cookie, allowing clients to retry with that DNS
    Cookie.
    The *allow_cookie* action will also accept requests over stateful
    transports, regardless of the presence of an DNS Cookie and regardless
    of the :ref:`answer-cookie` setting.
    UDP queries without a DNS Cookie receive REFUSED responses with the TC
    flag set, that may trigger fall back to TCP for those clients.

@@[email protected]@deny_non_local@@
    The
    :ref:`deny_non_local`
    action is for hosts that are only allowed to query for the
    authoritative :ref:`local-data`, they are not
    allowed full recursion but only the static data.
    Messages that are disallowed are dropped.

@@[email protected]@refuse_non_local@@
    The
    :ref:`refuse_non_local`
    action is for hosts that are only allowed to query for the
    authoritative :ref:`local-data`, they are not
    allowed full recursion but only the static data.
    Messages that are disallowed receive error code REFUSED.


By default only localhost (the 127.0.0.0/8 IP netblock, not the loopback
interface) is implicitly *allowed*, the rest is refused.
The default is *refused*, because that is protocol-friendly.
The DNS protocol is not designed to handle dropped packets due to policy,
and dropping may result in (possibly excessive) retried queries.

@@[email protected]@access-control-tag@@: * ""*
Assign tags to :ref:access-control
elements.
Clients using this access control element use localzones that are tagged
with one of these tags.

Tags must be defined in :ref:`define-tag`.
Enclose list of tags in quotes (``""``) and put spaces between tags.

If :ref:`access-control-tag` is
configured for a netblock that does not have an
:ref:`access-control`, an access-control
element with action :ref:`allow`
is configured for this netblock.

@@[email protected]@access-control-tag-action@@: * *
Set action for particular tag for given access control element.
If you have multiple tag values, the tag used to lookup the action is the
first tag match between
:ref:access-control-tag and
:ref:local-zone-tag where "first" comes
from the order of the :ref:define-tag values.

@@[email protected]@access-control-tag-data@@: * ""*
Set redirect data for particular tag for given access control element.

@@[email protected]@access-control-view@@: * *
Set view for given access control element.

@@[email protected]@interface-action@@: * *
Similar to :ref:access-control but for
interfaces.

The action is the same as the ones defined under
:ref:`access-control`.

Default action for interfaces is
:ref:`refuse`.
By default only localhost (the 127.0.0.0/8 IP netblock, not the loopback
interface) is implicitly allowed through the default
:ref:`access-control` behavior.
This also means that any attempt to use the **interface-\*:** options for
the loopback interface will not work as they will be overridden by the
implicit default "access-control: 127.0.0.0/8 allow" option.

.. note::
    The interface needs to be already specified with
    :ref:`interface` and that any
    **access-control\*:** option overrides all **interface-\*:**
    options for targeted clients.

@@[email protected]@interface-tag@@: * <"list of tags">*
Similar to :ref:access-control-tag but
for interfaces.

.. note::
    The interface needs to be already specified with
    :ref:`interface` and that any
    **access-control\*:** option overrides all **interface-\*:**
    options for targeted clients.

@@[email protected]@interface-tag-action@@: * *
Similar to
:ref:access-control-tag-action
but for interfaces.

.. note::
    The interface needs to be already specified with
    :ref:`interface` and that any
    **access-control\*:** option overrides all **interface-\*:**
    options for targeted clients.

@@[email protected]@interface-tag-data@@: * <"resource record string">*
Similar to
:ref:access-control-tag-data but
for interfaces.

.. note::
    The interface needs to be already specified with
    :ref:`interface` and that any
    **access-control\*:** option overrides all **interface-\*:**
    options for targeted clients.

@@[email protected]@interface-view@@: * *
Similar to :ref:access-control-view
but for interfaces.

.. note::
    The interface needs to be already specified with
    :ref:`interface` and that any
    **access-control\*:** option overrides all **interface-\*:**
    options for targeted clients.

@@[email protected]@chroot@@:
If :ref:chroot is enabled, you should pass the
configfile (from the commandline) as a full path from the original root.
After the chroot has been performed the now defunct portion of the config
file path is removed to be able to reread the config after a reload.

All other file paths (working dir, logfile, roothints, and key files) can
be specified in several ways: as an absolute path relative to the new root,
as a relative path to the working directory, or as an absolute path
relative to the original root.
In the last case the path is adjusted to remove the unused portion.

The pidfile can be either a relative path to the working directory, or an
absolute path relative to the original root.
It is written just prior to chroot and dropping permissions.
This allows the pidfile to be :file:`/var/run/unbound.pid` and the chroot
to be :file:`/var/unbound`, for example.
Note that Unbound is not able to remove the pidfile after termination when
it is located outside of the chroot directory.

Additionally, Unbound may need to access :file:`/dev/urandom` (for entropy)
from inside the chroot.

If given, a *chroot(2)* is done to the given directory.
If you give ``""`` no *chroot(2)* is performed.

Default: @UNBOUND_CHROOT_DIR@

@@[email protected]@username@@:
If given, after binding the port the user privileges are dropped.
If you give username: "" no user change is performed.

If this user is not capable of binding the port, reloads (by signal HUP)
will still retain the opened ports.
If you change the port number in the config file, and that new port number
requires privileges, then a reload will fail; a restart is needed.

Default: @UNBOUND_USERNAME@

@@[email protected]@directory@@:
Sets the working directory for the program.
On Windows the string "%EXECUTABLE%" tries to change to the directory that
:command:unbound.exe resides in.
If you give a :ref:server: directory: \<directory\> before
:ref:include file statements then those includes
can be relative to the working directory.

Default: @UNBOUND_RUN_DIR@

@@[email protected]@logfile@@:
If "" is given, logging goes to stderr, or nowhere once daemonized.
The logfile is appended to, in the following format:

.. code-block:: text

    [seconds since 1970] unbound[pid:tid]: type: message.

If this option is given, the :ref:`use-syslog`
option is internally set to ``no``.

The logfile is reopened (for append) when the config file is reread, on
SIGHUP.

Default: "" (disabled)

@@[email protected]@use-syslog@@:
Sets Unbound to send log messages to the syslogd, using syslog(3).
The log facility LOG_DAEMON is used, with identity "unbound".
The logfile setting is overridden when
:ref:use-syslog: yes is set.

Default: yes

@@[email protected]@log-identity@@:
If "" is given, then the name of the executable, usually
"unbound" is used to report to the log.
Enter a string to override it with that, which is useful on systems that
run more than one instance of Unbound, with different configurations, so
that the logs can be easily distinguished against.

Default: ""

@@[email protected]@log-time-ascii@@:
Sets logfile lines to use a timestamp in UTC ASCII.
No effect if using syslog, in that case syslog formats the timestamp
printed into the log files.

Default: no (prints the seconds since 1970 in brackets)

@@[email protected]@log-time-iso@@:
Log time in ISO8601 format, if
:ref:log-time-ascii: yes
is also set.

Default: no

@@[email protected]@log-queries@@:
Prints one line per query to the log, with the log timestamp and IP
address, name, type and class.
Note that it takes time to print these lines which makes the server
(significantly) slower.
Odd (nonprintable) characters in names are printed as '?'.

Default: no

@@[email protected]@log-replies@@:
Prints one line per reply to the log, with the log timestamp and IP
address, name, type, class, return code, time to resolve, from cache and
response size.
Note that it takes time to print these lines which makes the server
(significantly) slower.
Odd (nonprintable) characters in names are printed as '?'.

Default: no

@@[email protected]@log-tag-queryreply@@:
Prints the word 'query' and 'reply' with
:ref:log-queries and
:ref:log-replies.
This makes filtering logs easier.

Default: no (backwards compatible)

@@[email protected]@log-destaddr@@:
Prints the destination address, port and type in the
:ref:log-replies output.
This disambiguates what type of traffic, eg. UDP or TCP, and to what local
port the traffic was sent to.

Default: no

@@[email protected]@log-local-actions@@:
Print log lines to inform about local zone actions.
These lines are like the :ref:local-zone type inform print outs, but they are also
printed for the other types of local zones.

Default: no

@@[email protected]@log-servfail@@:
Print log lines that say why queries return SERVFAIL to clients.
This is separate from the verbosity debug logs, much smaller, and printed
at the error level, not the info level of debug info from verbosity.

Default: no

@@[email protected]@log-thread-id@@:
(Only on Linux and only when threads are available)
Logs the system-wide Linux thread ID instead of Unbound's internal thread
counter.
Can be useful when debugging with system tools.

Default: no

@@[email protected]@pidfile@@:
The process id is written to the file.
Default is :file:"@UNBOUND_PIDFILE@".
So,

.. code-block:: text

    kill -HUP `cat @UNBOUND_PIDFILE@`

triggers a reload,

.. code-block:: text

    kill -TERM `cat @UNBOUND_PIDFILE@`

gracefully terminates.

Default: @UNBOUND_PIDFILE@

@@[email protected]@root-hints@@:
Read the root hints from this file.
Default is nothing, using builtin hints for the IN class.
The file has the format of zone files, with root nameserver names and
addresses only.
The default may become outdated, when servers change, and then it is
possible to use a root hints file with specific servers.

Default: ""

@@[email protected]@hide-identity@@:
If enabled 'id.server' and 'hostname.bind' queries are REFUSED.

Default: no

@@[email protected]@identity@@:
Set the identity to report.
If set to "", then the hostname of the server is returned.

Default: ""

@@[email protected]@hide-version@@:
If enabled 'version.server' and 'version.bind' queries are REFUSED.

Default: no

@@[email protected]@version@@:
Set the version to report.
If set to "", then the package version is returned.

Default: ""

@@[email protected]@hide-http-user-agent@@:
If enabled the HTTP header User-Agent is not set.
Use with caution as some webserver configurations may reject HTTP requests
lacking this header.
If needed, it is better to explicitly set the
:ref:http-user-agent below.

Default: no

@@[email protected]@http-user-agent@@:
Set the HTTP User-Agent header for outgoing HTTP requests.
If set to "", then the package name and version are used.

Default: ""

@@[email protected]@nsid@@:
Add the specified nsid to the EDNS section of the answer when queried with
an NSID EDNS enabled packet.
As a sequence of hex characters or with 'ascii_' prefix and then an ASCII
string.

Default: (disabled)

@@[email protected]@hide-trustanchor@@:
If enabled 'trustanchor.unbound' queries are REFUSED.

Default: no

@@[email protected]@target-fetch-policy@@: <"list of numbers">
Set the target fetch policy used by Unbound to determine if it should fetch
nameserver target addresses opportunistically.
The policy is described per dependency depth.

The number of values determines the maximum dependency depth that Unbound
will pursue in answering a query.
A value of -1 means to fetch all targets opportunistically for that
dependency depth.
A value of 0 means to fetch on demand only.
A positive value fetches that many targets opportunistically.

Enclose the list between quotes (``""``) and put spaces between numbers.
Setting all zeroes, "0 0 0 0 0" gives behaviour closer to that of BIND 9,
while setting "-1 -1 -1 -1 -1" gives behaviour rumoured to be closer to
that of BIND 8.

Default:  "3 2 1 0 0"

@@[email protected]@harden-short-bufsize@@:
Very small EDNS buffer sizes from queries are ignored and are instead
set to the normal UDP packet size (512 bytes).

Default: yes (per :rfc:`6891`)

@@[email protected]@harden-large-queries@@:
Very large queries are ignored.
The cutoff value is chosen to be the normal UDP packet size (512 bytes).
Default is no, since it is legal protocol wise to send these, and could be
necessary for operation if TSIG or EDNS payload is very large.

Default: no

@@[email protected]@harden-glue@@:
Will trust glue only if it is within the servers authority.

Default: yes

@@[email protected]@harden-unverified-glue@@:
Will trust only in-zone glue.
Will try to resolve all out of zone (unverified) glue.
Will fallback to the original glue if unable to resolve.

Default: no

@@[email protected]@harden-dnssec-stripped@@:
Require DNSSEC data for trust-anchored zones, if such data is absent, the
zone becomes bogus.
If turned off, and no DNSSEC data is received (or the DNSKEY data fails to
validate), then the zone is made insecure, this behaves like there is no
trust anchor.
You could turn this off if you are sometimes behind an intrusive firewall
(of some sort) that removes DNSSEC data from packets, or a zone changes
from signed to unsigned to badly signed often.
If turned off you run the risk of a downgrade attack that disables security
for a zone.

Default: yes

@@[email protected]@harden-below-nxdomain@@:
From :rfc:8020 (with title "NXDOMAIN: There Really Is Nothing
Underneath"), returns NXDOMAIN to queries for a name below another name
that is already known to be NXDOMAIN.
DNSSEC mandates NOERROR for empty nonterminals, hence this is possible.
Very old software might return NXDOMAIN for empty nonterminals (that
usually happen for reverse IP address lookups), and thus may be
incompatible with this.
To try to avoid this only DNSSEC-secure NXDOMAINs are used, because the old
software does not have DNSSEC.

.. note::
    The NXDOMAIN must be secure, this means NSEC3 with optout is
    insufficient.

Default: yes

@@[email protected]@harden-referral-path@@:
Harden the referral path by performing additional queries for
infrastructure data.
Validates the replies if trust anchors are configured and the zones are
signed.
This enforces DNSSEC validation on nameserver NS sets and the nameserver
addresses that are encountered on the referral path to the answer.
Default is off, because it burdens the authority servers, and it is not RFC
standard, and could lead to performance problems because of the extra query
load that is generated.
Experimental option.
If you enable it consider adding more numbers after the
:ref:target-fetch-policy to increase
the max depth that is checked to.

Default: no

@@[email protected]@harden-algo-downgrade@@:
Harden against algorithm downgrade when multiple algorithms are advertised
in the DS record.
This works by first choosing only the strongest DS digest type as per
:rfc:4509 (Unbound treats the highest algorithm as the strongest) and
then expecting signatures from all the advertised signing algorithms from
the chosen DS(es) to be present.
If no, allows any one supported algorithm to validate the zone, even if
other advertised algorithms are broken.
:rfc:6840 mandates that zone signers must produce zones signed with all
advertised algorithms, but sometimes they do not.
:rfc:6840 also clarifies that this requirement is not for validators and
validators should accept any single valid path.
It should thus be explicitly noted that this option violates :rfc:6840
for DNSSEC validation and should only be used to perform a signature
completeness test to support troubleshooting.

.. warning::
    Using this option may break DNSSEC resolution with non :rfc:`6840`
    conforming signers and/or in multi-signer configurations that don't
    send all the advertised signatures.

Default: no

@@[email protected]@harden-unknown-additional@@:
Harden against unknown records in the authority section and additional
section.
If no, such records are copied from the upstream and presented to the
client together with the answer.
If yes, it could hamper future protocol developments that want to add
records.

Default: no

@@[email protected]@harden-cname-follow@@:
Harden CNAME redirections by following them.
If no, then upstream CNAME and DNAME redirections are allowed in a
response without checking with further messages if those are valid.
It can only really be disabled safely on localhost net or encrypted
connectivity.
Default is on to protect the cache integrity.

Default: yes

@@[email protected]@use-caps-for-id@@:
Use 0x20-encoded random bits in the query to foil spoof attempts.
This perturbs the lowercase and uppercase of query names sent to authority
servers and checks if the reply still has the correct casing.
This feature is an experimental implementation of draft dns-0x20.

Default: no

@@[email protected]@caps-exempt@@:
Exempt the domain so that it does not receive caps-for-id perturbed
queries.
For domains that do not support 0x20 and also fail with fallback because
they keep sending different answers, like some load balancers.
Can be given multiple times, for different domains.

@@[email protected]@caps-whitelist@@:
Alternate syntax for :ref:caps-exempt.

@@[email protected]@qname-minimisation@@:
Send minimum amount of information to upstream servers to enhance privacy.
Only send minimum required labels of the QNAME and set QTYPE to A when
possible.
Best effort approach; full QNAME and original QTYPE will be sent when
upstream replies with a RCODE other than NOERROR, except when receiving
NXDOMAIN from a DNSSEC signed zone.

Default: yes

@@[email protected]@qname-minimisation-strict@@:
QNAME minimisation in strict mode.
Do not fall-back to sending full QNAME to potentially broken nameservers.
A lot of domains will not be resolvable when this option in enabled.
Only use if you know what you are doing.
This option only has effect when
:ref:qname-minimisation is enabled.

Default: no

@@[email protected]@aggressive-nsec@@:
Aggressive NSEC uses the DNSSEC NSEC chain to synthesize NXDOMAIN and other
denials, using information from previous NXDOMAINs answers.
It helps to reduce the query rate towards targets that get a very high
nonexistent name lookup rate.

Default: yes

@@[email protected]@private-address@@: **
Give IPv4 of IPv6 addresses or classless subnets.
These are addresses on your private network, and are not allowed to be
returned for public internet names.
Any occurrence of such addresses are removed from DNS answers.
Additionally, the DNSSEC validator may mark the answers bogus.
This protects against so-called DNS Rebinding, where a user browser is
turned into a network proxy, allowing remote access through the browser to
other parts of your private network.

The option removes resource records of types A, AAAA, SVCB and HTTPS
that match the filter.
Inside the SVCB and HTTPS records, the svcparams of type ipv4hint
and ipv6hint are checked for matches.

Some names can be allowed to contain your private addresses, by default all
the :ref:`local-data` that you configured is
allowed to, and you can specify additional names using
:ref:`private-domain`.
No private addresses are enabled by default.

We consider to enable this for the :rfc:`1918` private IP address space by
default in later releases.
That would enable private addresses for ``10.0.0.0/8``, ``172.16.0.0/12``,
``192.168.0.0/16``, ``169.254.0.0/16``, ``fd00::/8`` and ``fe80::/10``,
since the RFC standards say these addresses should not be visible on the
public internet.

Turning on ``127.0.0.0/8`` would hinder many spamblocklists as they use
that.
Adding ``::ffff:0:0/96`` stops IPv4-mapped IPv6 addresses from bypassing
the filter.

@@[email protected]@private-domain@@:
Allow this domain, and all its subdomains to contain private addresses.
Give multiple times to allow multiple domain names to contain private
addresses.

Default: (none)

@@[email protected]@unwanted-reply-threshold@@:
If set, a total number of unwanted replies is kept track of in every
thread.
When it reaches the threshold, a defensive action is taken and a warning is
printed to the log.
The defensive action is to clear the rrset and message caches, hopefully
flushing away any poison.
A value of 10 million is suggested.

It is useful to add 0.0.0.0/8 and '::' to the
:ref:`do-not-query-address` list.
Otherwise they may be answered, from localhost, and the different source
makes an unwanted reply that unnecessarily ticks up.
The :ref:`do-not-query-localhost`
option includes them, the zero subnets, when it is enabled.

Default: 0 (disabled)

@@[email protected]@do-not-query-address@@: **
Do not query the given IP address.
Can be IPv4 or IPv6.
Append /num to indicate a classless delegation netblock, for example like
10.2.3.4/24 or 2001::11/64.

Default: (none)

@@[email protected]@do-not-query-localhost@@:
If yes, localhost is added to the
:ref:do-not-query-address entries,
both IPv4 127.0.0.1/8 (also ::ffff:127.0.0.0/104) and IPv6 ::1.
Additionally, the zero subnets 0.0.0.0/8 (also ::ffff:0:0/96) and
:: are added to the list since on some systems they route to
localhost as well.
If no, then localhost can be used to send queries to.

Default: yes

@@[email protected]@prefetch@@:
If yes, cache hits on message cache elements that are on their last 10
percent of their TTL value trigger a prefetch to keep the cache up to date.
Turning it on gives about 10 percent more traffic and load on the machine,
but popular items do not expire from the cache.

Default: no

@@[email protected]@prefetch-key@@:
If yes, fetch the DNSKEYs earlier in the validation process, when a DS
record is encountered.
This lowers the latency of requests.
It does use a little more CPU.
Also if the cache is set to 0, it is no use.

Default: no

@@[email protected]@deny-any@@:
If yes, deny queries of type ANY with an empty response.
If disabled, Unbound responds with a short list of resource records if some
can be found in the cache and makes the upstream type ANY query if there
are none.
The option stops the DNSSEC validation from processing, possibly lengthy,
ANY responses, when the option is enabled.

Default: no

@@[email protected]@rrset-roundrobin@@:
If yes, Unbound rotates RRSet order in response (the random number is taken
from the query ID, for speed and thread safety).

Default: yes

@@[email protected]@minimal-responses@@:
If yes, Unbound does not insert authority/additional sections into response
messages when those sections are not required.
This reduces response size significantly, and may avoid TCP fallback for
some responses which may cause a slight speedup.
The default is yes, even though the DNS protocol RFCs mandate these
sections, and the additional content could save roundtrips for clients that
use the additional content.
However these sections are hardly used by clients.
Enabling prefetch can benefit clients that need the additional content
by trying to keep that content fresh in the cache.

Default: yes

@@[email protected]@disable-dnssec-lame-check@@:
If yes, disables the DNSSEC lameness check in the iterator.
This check sees if RRSIGs are present in the answer, when DNSSEC is
expected, and retries another authority if RRSIGs are unexpectedly missing.
The validator will insist in RRSIGs for DNSSEC signed domains regardless of
this setting, if a trust anchor is loaded.

Default: no

@@[email protected]@module-config@@: ""
Module configuration, a list of module names separated by spaces, surround
the string with quotes ("").
The modules can be respip, validator, or iterator (and possibly
more, see below).

.. note::
    The ordering of the modules is significant, the order decides the order
    of processing.

Setting this to just ``"iterator"`` results in a non-validating server.
Setting this to ``"validator iterator"`` (default) enables the DNSSEC
validator module but not DNSSEC validation.

.. note::
    To turn on DNSSEC validation you must configure trust-anchors.

Adding ``respip`` to the front will cause RPZ processing to be done on all
queries.

Most modules that need to be listed here have to be listed at the beginning
of the line.

The ``subnetcache`` module has to be listed just before the iterator.

The ``python`` module can be listed in different places, it then processes
the output of the module it is just before.

The ``dynlib`` module can be listed pretty much anywhere, it is only a very
thin wrapper that allows dynamic libraries to run in its place.

Default: "validator iterator"

@@[email protected]@trust-anchor-file@@:
File with trusted keys for validation.
Both DS and DNSKEY entries can appear in the file.
The format of the file is the standard DNS Zone file format.

Default: "" (no trust anchor file)

@@[email protected]@auto-trust-anchor-file@@:
File with trust anchor for one zone, which is tracked with :rfc:5011
probes.
The probes are run several times per month, thus the machine must be online
frequently.
The initial file can be one with contents as described in
:ref:trust-anchor-file.
The file is written to when the anchor is updated, so the Unbound user must
have write permission.
Write permission to the file, but also to the directory it is in (to create
a temporary file, which is necessary to deal with filesystem full events),
it must also be inside the :ref:chroot (if that is
used).

Default: "" (no auto trust anchor file)

@@[email protected]@trust-anchor@@: ""
A DS or DNSKEY RR for a key to use for validation.
Multiple entries can be given to specify multiple trusted keys, in addition
to the :ref:trust-anchor-file.
The resource record is entered in the same format as dig(1) or drill(1)
prints them, the same format as in the zone file.
Has to be on a single line, with "" around it.
A TTL can be specified for ease of cut and paste, but is ignored.
A class can be specified, but class IN is default.

Default: (none)

@@[email protected]@trusted-keys-file@@:
File with trusted keys for validation.
Specify more than one file with several entries, one file per entry.
Like :ref:trust-anchor-file but has a
different file format.
Format is BIND-9 style format, the trusted-keys { name flag proto algo "key"; }; clauses are read.
It is possible to use wildcards with this statement, the wildcard is
expanded on start and on reload.

A wildcard that matches no files is not an error: the entry loads no
trust anchors, and the condition is logged at operational verbosity.

Default: "" (no trusted keys file)

@@[email protected]@trust-anchor-signaling@@:
Send :rfc:8145 key tag query after trust anchor priming.

Default: yes

@@[email protected]@root-key-sentinel@@:
Root key trust anchor sentinel.

Default: yes

@@[email protected]@domain-insecure@@:
Sets to be insecure, DNSSEC chain of trust is ignored
towards the .
So a trust anchor above the domain name can not make the domain secure with
a DS record, such a DS record is then ignored.
Can be given multiple times to specify multiple domains that are treated as
if unsigned.
If you set trust anchors for the domain they override this setting (and the
domain is secured).

This can be useful if you want to make sure a trust anchor for external
lookups does not affect an (unsigned) internal domain.
A DS record externally can create validation failures for that internal
domain.

Default: (none)

@@[email protected]@val-override-date@@:
.. warning:: Debugging feature!

If enabled by giving a RRSIG style date, that date is used for verifying
RRSIG inception and expiration dates, instead of the current date.
Do not set this unless you are debugging signature inception and
expiration.
The value -1 ignores the date altogether, useful for some special
applications.

Default: 0 (disabled)

@@[email protected]@val-sig-skew-min@@:
Minimum number of seconds of clock skew to apply to validated signatures.
A value of 10% of the signature lifetime (expiration - inception) is used,
capped by this setting.
Default is 3600 (1 hour) which allows for daylight savings differences.
Lower this value for more strict checking of short lived signatures.

Default: 3600 (1 hour)

@@[email protected]@val-sig-skew-max@@:
Maximum number of seconds of clock skew to apply to validated signatures.
A value of 10% of the signature lifetime (expiration - inception) is used,
capped by this setting.
Default is 86400 (24 hours) which allows for timezone setting problems in
stable domains.
Setting both min and max very low disables the clock skew allowances.
Setting both min and max very high makes the validator check the signature
timestamps less strictly.

Default: 86400 (24 hours)

@@[email protected]@val-max-restart@@:
The maximum number the validator should restart validation with another
authority in case of failed validation.

Default: 5

@@[email protected]@val-bogus-ttl@@:
The time to live for bogus data.
This is data that has failed validation; due to invalid signatures or other
checks.
The TTL from that data cannot be trusted, and this value is used instead.
The time interval prevents repeated revalidation of bogus data.

Default: 60

@@[email protected]@val-clean-additional@@:
Instruct the validator to remove data from the additional section of secure
messages that are not signed properly.
Messages that are insecure, bogus, indeterminate or unchecked are not
affected.
Use this setting to protect the users that rely on this validator for
authentication from potentially bad data in the additional section.

Default: no

@@[email protected]@val-log-level@@:
Have the validator print validation failures to the log.
Regardless of the verbosity setting.

At 1, for every user query that fails a line is printed to the logs.
This way you can monitor what happens with validation.
Use a diagnosis tool, such as dig or drill, to find out why validation is
failing for these queries.

At 2, not only the query that failed is printed but also the reason why
Unbound thought it was wrong and which server sent the faulty data.

Default: 0 (disabled)

@@[email protected]@val-permissive-mode@@:
Instruct the validator to mark bogus messages as indeterminate.
The security checks are performed, but if the result is bogus (failed
security), the reply is not withheld from the client with SERVFAIL as
usual.
The client receives the bogus data.
For messages that are found to be secure the AD bit is set in replies.
Also logging is performed as for full validation.

Default: no

@@[email protected]@ignore-cd-flag@@:
Instruct Unbound to ignore the CD flag from clients and refuse to return
bogus answers to them.
Thus, the CD (Checking Disabled) flag does not disable checking any more.
This is useful if legacy (w2008) servers that set the CD flag but cannot
validate DNSSEC themselves are the clients, and then Unbound provides them
with DNSSEC protection.

Default: no

@@[email protected]@disable-edns-do@@:
Disable the EDNS DO flag in upstream requests.
It breaks DNSSEC validation for Unbound's clients.
This results in the upstream name servers to not include DNSSEC records in
their replies and could be helpful for devices that cannot handle DNSSEC
information.
When the option is enabled, clients that set the DO flag receive no EDNS
record in the response to indicate the lack of support to them.
If this option is enabled but Unbound is already configured for DNSSEC
validation (i.e., the validator module is enabled; default) this option is
implicitly turned off with a warning as to not break DNSSEC validation in
Unbound.

Default: no

@@[email protected]@serve-expired@@:
If enabled, Unbound attempts to serve old responses from cache with a TTL
of :ref:serve-expired-reply-ttl in
the response.
By default the expired answer will be used after a resolution attempt
errored out or is taking more than
:ref:serve-expired-client-timeout
to resolve.

Default: no

@@[email protected]@serve-expired-ttl@@:
Limit serving of expired responses to configured seconds after expiration.
0 disables the limit.
This option only applies when
:ref:serve-expired is enabled.
A suggested value per RFC 8767 is between 86400 (1 day) and 259200 (3 days).
The default is 86400.

Default: 86400

@@[email protected]@serve-expired-ttl-reset@@:
Set the TTL of expired records to the
:ref:serve-expired-ttl value after a
failed attempt to retrieve the record from upstream.
This makes sure that the expired records will be served as long as there
are queries for it.

Default: no

@@[email protected]@serve-expired-reply-ttl@@:
TTL value to use when replying with expired data.
If
:ref:serve-expired-client-timeout
is also used then it is RECOMMENDED to use 30 as the value (:rfc:8767).

This value is capped by the original TTL of the record.
This means that records with higher original TTL than this value will use
this value for expired replies.
Records with lower original TTL than this value will use their original TTL
for expired replies.

Default: 30

@@[email protected]@serve-expired-client-timeout@@:
Time in milliseconds before replying to the client with expired data.
This essentially enables the serve-stale behavior as specified in
:rfc:8767 that first tries to resolve before immediately responding with
expired data.
Setting this to 0 will disable this behavior and instead serve the
expired record immediately from the cache before attempting to refresh it
via resolution.

Default: 1800

@@[email protected]@serve-original-ttl@@:
If enabled, Unbound will always return the original TTL as received from
the upstream name server rather than the decrementing TTL as stored in the
cache.
This feature may be useful if Unbound serves as a front-end to a hidden
authoritative name server.

Enabling this feature does not impact cache expiry, it only changes the TTL
Unbound embeds in responses to queries.

.. note::
    Enabling this feature implicitly disables enforcement of the configured
    minimum and maximum TTL, as it is assumed users who enable this feature
    do not want Unbound to change the TTL obtained from an upstream server.

.. note::
    The values set using :ref:`cache-min-ttl`
    and :ref:`cache-max-ttl` are ignored.

Default: no

@@[email protected]@val-nsec3-keysize-iterations@@: <"list of values">
List of keysize and iteration count values, separated by spaces, surrounded
by quotes.
This determines the maximum allowed NSEC3 iteration count before a message
is simply marked insecure instead of performing the many hashing
iterations.
The list must be in ascending order and have at least one entry.
If you set it to "1024 65535" there is no restriction to NSEC3 iteration
values.

.. note::
    This table must be kept short; a very long list could cause slower
    operation.

Default: "1024 150 2048 150 4096 150"

@@[email protected]@zonemd-permissive-mode@@:
If enabled the ZONEMD verification failures are only logged and do not
cause the zone to be blocked and only return servfail.
Useful for testing out if it works, or if the operator only wants to be
notified of a problem without disrupting service.

Default: no

@@[email protected]@add-holddown@@:
Instruct the
:ref:auto-trust-anchor-file probe
mechanism for :rfc:5011 autotrust updates to add new trust anchors only
after they have been visible for this time.

Default: 2592000 (30 days as per the RFC)

@@[email protected]@del-holddown@@:
Instruct the
:ref:auto-trust-anchor-file probe
mechanism for :rfc:5011 autotrust updates to remove revoked trust anchors
after they have been kept in the revoked list for this long.

Default: 2592000 (30 days as per the RFC)

@@[email protected]@keep-missing@@:
Instruct the
:ref:auto-trust-anchor-file probe
mechanism for :rfc:5011 autotrust updates to remove missing trust anchors
after they have been unseen for this long.
This cleans up the state file if the target zone does not perform trust
anchor revocation, so this makes the auto probe mechanism work with zones
that perform regular (non-5011) rollovers.
The value 0 does not remove missing anchors, as per the RFC.

Default: 31622400 (366 days)

@@[email protected]@permit-small-holddown@@:
Debug option that allows the autotrust 5011 rollover timers to assume very
small values.

Default: no

@@[email protected]@key-cache-size@@:
Number of bytes size of the key cache.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).

Default: 4m

@@[email protected]@key-cache-slabs@@:
Number of slabs in the key cache.
Slabs reduce lock contention by threads.
Must be set to a power of 2.
Setting (close) to the number of cpus is a fairly good setting.
If left unconfigured, it will be configured automatically to be a power of
2 close to the number of configured threads in multi-threaded environments.

Default: (unconfigured)

@@[email protected]@neg-cache-size@@:
Number of bytes size of the aggressive negative cache.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).

Default: 1m

@@[email protected]@unblock-lan-zones@@:
If enabled, then for private address space, the reverse lookups are no
longer filtered.
This allows Unbound when running as dns service on a host where it provides
service for that host, to put out all of the queries for the 'lan'
upstream.
When enabled, only localhost, 127.0.0.1 reverse and ::1 reverse
zones are configured with default local zones.
Disable the option when Unbound is running as a (DHCP-) DNS network
resolver for a group of machines, where such lookups should be filtered
(RFC compliance), this also stops potential data leakage about the local
network to the upstream DNS servers.

Default: no

@@[email protected]@insecure-lan-zones@@:
If enabled, then reverse lookups in private address space are not
validated.
This is usually required whenever
:ref:unblock-lan-zones is used.

Default: no

@@[email protected]@local-zone@@:
Configure a local zone.
The type determines the answer to give if there is no match from
:ref:local-data.
The types are
:ref:deny,
:ref:refuse,
:ref:static,
:ref:transparent,
:ref:redirect,
:ref:nodefault,
:ref:typetransparent,
:ref:inform,
:ref:inform_deny,
:ref:inform_redirect,
:ref:always_transparent,
:ref:block_a,
:ref:block_aaaa,
:ref:block_a_wdata,
:ref:block_aaaa_wdata,
:ref:always_refuse,
:ref:always_nxdomain,
:ref:always_null,
:ref:noview,
and are explained below.
After that the default settings are listed.
Use :ref:local-data to enter data into the
local zone.
Answers for local zones are authoritative DNS answers.
By default the zones are class IN.

If you need more complicated authoritative data, with referrals,
wildcards, CNAME/DNAME support, or DNSSEC authoritative service,
setup a :ref:`stub-zone` for it as detailed in the
stub zone section below.
A :ref:`stub-zone` can be used to have unbound
send queries to another server, an authoritative server, to fetch the
information.
With a :ref:`forward-zone`, unbound sends
queries to a server that is a recursive server to fetch the information.
With an :ref:`auth-zone` a zone can be loaded from
file and used, it can be used like a local zone for users downstream, or
the :ref:`auth-zone` information can be used to fetch
information from when resolving like it is an upstream server.
The :ref:`forward-zone` and
:ref:`auth-zone` options are described in their
sections below.
If you want to perform filtering of the information that the users can
fetch, the :ref:`local-zone` and
:ref:`local-data` statements allow for this, but
also the :ref:`rpz` functionality can be used, described
in the RPZ section.

@@[email protected]@deny@@
    Do not send an answer, drop the query.
    If there is a match from local data, the query is answered.

@@[email protected]@refuse@@
    Send an error message reply, with rcode REFUSED.
    If there is a match from local data, the query is answered.

@@[email protected]@static@@
    If there is a match from local data, the query is answered.
    Otherwise, the query is answered with NODATA or NXDOMAIN.
    For a negative answer a SOA is included in the answer if present as
    :ref:`local-data` for the zone apex domain.

@@[email protected]@transparent@@
    If there is a match from :ref:`local-data`,
    the query is answered.
    Otherwise if the query has a different name, the query is resolved
    normally.
    If the query is for a name given in
    :ref:`local-data` but no such type of data is
    given in localdata, then a NOERROR NODATA answer is returned.
    If no :ref:`local-zone` is given
    :ref:`local-data` causes a transparent zone
    to be created by default.

@@[email protected]@typetransparent@@
    If there is a match from local data, the query is answered.
    If the query is for a different name, or for the same name but for a
    different type, the query is resolved normally.
    So, similar to
    :ref:`transparent` but types
    that are not listed in local data are resolved normally, so if an A
    record is in the local data that does not cause a NODATA reply for AAAA
    queries.

@@[email protected]@redirect@@
    The query is answered from the local data for the zone name.
    There may be no local data beneath the zone name.
    This answers queries for the zone, and all subdomains of the zone with
    the local data for the zone.
    It can be used to redirect a domain to return a different address
    record to the end user, with:

    .. code-block:: text

        local-zone: "example.com." redirect
        local-data: "example.com. A 127.0.0.1"

    queries for ``www.example.com`` and ``www.foo.example.com`` are
    redirected, so that users with web browsers cannot access sites with
    suffix example.com.

    A ``CNAME`` record can also be provided via local-data:

    .. code-block:: text

        local-zone: "example.com." redirect
        local-data: "example.com. CNAME www.example.org."

    In that case, the ``CNAME`` is resolved and the answer
    includes resolved target records as well.
    The ``CNAME`` record has to be with the zone name of the local-zone,
    and there can be one CNAME, not more.
    The ``CNAME`` record has to be at the zone apex of the
    ``redirect`` zone, then it is used for redirection.
    The resolution proceeds with upstream DNS resolution, and
    that does not include the lookup in local zones.
    So the record is not able to point in local zones, but it
    can point to upstream DNS answers.

    ``CNAME`` resolution is supported only in type ``redirect``
    local-zone, and in type ``inform_redirect`` local-zone.

    As different from ``CNAME`` records that are used elsewhere, in
    the ``redirect`` type local-zone, it is supported that in the target
    of the record a wildcard label gets expanded to the query name, with
    for example: ``example.com. CNAME *.foo.net.`` gets expanded
    to ``www.example.com. CNAME www.example.com.foo.net.``.

@@[email protected]@inform@@
    The query is answered normally, same as
    :ref:`transparent`.
    The client IP address (@portnumber) is printed to the logfile.
    The log message is:

    .. code-block:: text

        timestamp, unbound-pid, info: zonename inform IP@port queryname type class.

    This option can be used for normal resolution, but machines looking up
    infected names are logged, eg. to run antivirus on them.

@@[email protected]@inform_deny@@
    The query is dropped, like
    :ref:`deny`, and logged, like
    :ref:`inform`.
    Ie. find infected machines without answering the queries.

@@[email protected]@inform_redirect@@
    The query is redirected, like
    :ref:`redirect`, and logged,
    like :ref:`inform`.
    Ie. answer queries with fixed data and also log the machines that ask.

@@[email protected]@always_transparent@@
    Like :ref:`transparent`, but
    ignores local data and resolves normally.

@@[email protected]@block_a@@
    Like :ref:`transparent`, but
    ignores local data and resolves normally all query types excluding A.
    For A queries it unconditionally returns NODATA.
    Useful in cases when there is a need to explicitly force all apps to
    use IPv6 protocol and avoid any queries to IPv4.

@@[email protected]@block_aaaa@@
    Like :ref:`transparent` or
    :ref:`block_a`, but
    ignores local data and resolves normally all query types excluding AAAA.
    For AAAA queries it unconditionally returns NODATA.
    Useful in cases when there is a need to explicitly force all apps to
    use IPv4 protocol and avoid any queries to IPv6.

@@[email protected]@block_a_wdata@@
    Like :ref:`block_a`, but
    uses local data if present.
    If there is local data that is returned, and it acts like transparent.
    For A queries it returns NODATA.

@@[email protected]@block_aaaa_wdata@@
    Like :ref:`block_aaaa`, but
    uses local data if present.
    If there is local data that is returned, and it acts like transparent.
    For AAAA queries it returns NODATA.

@@[email protected]@always_refuse@@
    Like :ref:`refuse`, but ignores
    local data and refuses the query.
    This type also blocks queries of type DS for the zone name.
    That can break the DNSSEC chain of trust, but it is refused anyway.
    The block for type DS assists in more completely blocking the zone.

@@[email protected]@always_nxdomain@@
    Like :ref:`static`, but ignores
    local data and returns NXDOMAIN for the query.

@@[email protected]@always_nodata@@
    Like :ref:`static`, but ignores
    local data and returns NODATA for the query.

@@[email protected]@always_deny@@
    Like :ref:`deny`, but ignores local
    data and drops the query.

@@[email protected]@always_null@@
    Always returns ``0.0.0.0`` or ``::0`` for every name in the zone.
    Like :ref:`redirect` with zero
    data for A and AAAA.
    Ignores local data in the zone.
    Used for some block lists.

@@[email protected]@noview@@
    Breaks out of that view and moves towards the global local zones for
    answer to the query.
    If the :ref:`view-first` is no, it'll
    resolve normally.
    If :ref:`view-first` is enabled, it'll
    break perform that step and check the global answers.
    For when the view has view specific overrides but some zone has to be
    answered from global local zone contents.

@@[email protected]@nodefault@@
    Used to turn off default contents for AS112 zones.
    The other types also turn off default contents for the zone.
    The :ref:`nodefault` option has
    no other effect than turning off default contents for the given zone.
    Use :ref:`nodefault` if you use
    exactly that zone, if you want to use a subzone, use
    :ref:`transparent`.

The default zones are localhost, reverse ``127.0.0.1`` and ``::1``, the
``home.arpa``, ``resolver.arpa``, ``service.arpa``, ``onion``, ``test``,
``invalid`` and the AS112 zones.
The AS112 zones are reverse DNS zones for private use and reserved IP
addresses for which the servers on the internet cannot provide correct
answers.
They are configured by default to give NXDOMAIN (no reverse information)
answers.

The defaults can be turned off by specifying your own
:ref:`local-zone` of that name, or using the
:ref:`nodefault` type.
Below is a list of the default zone contents.

@@[email protected]@localhost@@
    The IPv4 and IPv6 localhost information is given.
    NS and SOA records are provided for completeness and to satisfy some
    DNS update tools.
    Default content:

    .. code-block:: text

        local-zone: "localhost." redirect
        local-data: "localhost. 10800 IN NS localhost."
        local-data: "localhost. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
        local-data: "localhost. 10800 IN A 127.0.0.1"
        local-data: "localhost. 10800 IN AAAA ::1"

@@[email protected]@reverse IPv4 loopback@@
    Default content:

    .. code-block:: text

        local-zone: "127.in-addr.arpa." static
        local-data: "127.in-addr.arpa. 10800 IN NS localhost."
        local-data: "127.in-addr.arpa. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
        local-data: "1.0.0.127.in-addr.arpa. 10800 IN PTR localhost."

@@[email protected]@reverse IPv6 loopback@@
    Default content:

    .. code-block:: text

        local-zone: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." static
        local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN NS localhost."
        local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
        local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN PTR localhost."

@@[email protected]@home.arpa@@ (:rfc:`8375`)
    Default content:

    .. code-block:: text

        local-zone: "home.arpa." static
        local-data: "home.arpa. 10800 IN NS localhost."
        local-data: "home.arpa. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"

@@[email protected]@resolver.arpa@@ (:rfc:`9462`)
    Default content:

    .. code-block:: text

        local-zone: "resolver.arpa." static
        local-data: "resolver.arpa. 10800 IN NS localhost."
        local-data: "resolver.arpa. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"

@@[email protected]@service.arpa@@ (draft-ietf-dnssd-srp-25)
    Default content:

    .. code-block:: text

        local-zone: "service.arpa." static
        local-data: "service.arpa. 10800 IN NS localhost."
        local-data: "service.arpa. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"

@@[email protected]@onion@@ (:rfc:`7686`)
    Default content:

    .. code-block:: text

        local-zone: "onion." static
        local-data: "onion. 10800 IN NS localhost."
        local-data: "onion. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"

@@[email protected]@test@@ (:rfc:`6761`)
    Default content:

    .. code-block:: text

        local-zone: "test." static
        local-data: "test. 10800 IN NS localhost."
        local-data: "test. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"

@@[email protected]@invalid@@ (:rfc:`6761`)
    Default content:

    .. code-block:: text

        local-zone: "invalid." static
        local-data: "invalid. 10800 IN NS localhost."
        local-data: "invalid. 10800 IN SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"

@@[email protected]@reverse local use zones@@ (:rfc:`1918`)
    Reverse data for zones ``10.in-addr.arpa``, ``16.172.in-addr.arpa`` to
    ``31.172.in-addr.arpa``, ``168.192.in-addr.arpa``.
    The :ref:`local-zone` is set static and as
    :ref:`local-data` SOA and NS records are
    provided.

@@[email protected]@special-use IPv4 Addresses@@ (:rfc:`3330`)
    Reverse data for zones ``0.in-addr.arpa`` (this), ``254.169.in-addr.arpa`` (link-local),
    ``2.0.192.in-addr.arpa`` (TEST NET 1), ``100.51.198.in-addr.arpa``
    (TEST NET 2), ``113.0.203.in-addr.arpa`` (TEST NET 3),
    ``255.255.255.255.in-addr.arpa`` (broadcast).
    And from ``64.100.in-addr.arpa`` to ``127.100.in-addr.arpa`` (Shared
    Address Space).

@@[email protected]@reverse IPv6 unspecified@@ (:rfc:`4291`)
    Reverse data for zone
    ``0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.``

@@[email protected]@reverse IPv6 Locally Assigned Local Addresses@@ (:rfc:`4193`)
    Reverse data for zone ``D.F.ip6.arpa``.

@@[email protected]@reverse IPv6 Link Local Addresses@@ (:rfc:`4291`)
    Reverse data for zones ``8.E.F.ip6.arpa`` to ``B.E.F.ip6.arpa``.

@@[email protected]@reverse IPv6 Example Prefix@@
    Reverse data for zone ``8.B.D.0.1.0.0.2.ip6.arpa``.
    This zone is used for tutorials and examples.
    You can remove the block on this zone with:

    .. code-block:: text

        local-zone: 8.B.D.0.1.0.0.2.ip6.arpa. nodefault

You can also selectively unblock a part of the zone by making that part
transparent with a :ref:`local-zone` statement.
This also works with the other default zones.

@@[email protected]@local-data@@: ""
Configure local data, which is served in reply to queries for it.
The query has to match exactly unless you configure the
:ref:local-zone as redirect.
If not matched exactly, the :ref:local-zone
type determines further processing.
If :ref:local-data is configured that is not a
subdomain of a :ref:local-zone, a
:ref:transparent local-zone is
configured.
For record types such as TXT, use single quotes, as in:

.. code-block:: text

    local-data: 'example. TXT "text"'

.. note::
    If you need more complicated authoritative data, with referrals,
    wildcards, CNAME/DNAME support, or DNSSEC authoritative service, setup
    a :ref:`stub-zone` for it as detailed in the stub
    zone section below.

@@[email protected]@local-data-ptr@@: "IPaddr name"
Configure local data shorthand for a PTR record with the reversed IPv4 or
IPv6 address and the host name.
For example "192.0.2.4 www.example.com".
TTL can be inserted like this: "2001:db8::4 7200 www.example.com"

@@[email protected]@local-zone-tag@@: <"list of tags">
Assign tags to local zones.
Tagged localzones will only be applied when the used
:ref:access-control element has a matching
tag.
Tags must be defined in :ref:define-tag.
Enclose list of tags in quotes ("") and put spaces between tags.
When there are multiple tags it checks if the intersection of the list of
tags for the query and :ref:local-zone-tag
is non-empty.

@@[email protected]@local-zone-override@@:
Override the local zone type for queries from addresses matching netblock.
Use this localzone type, regardless the type configured for the local zone
(both tagged and untagged) and regardless the type configured using
:ref:access-control-tag-action.

@@[email protected]@response-ip@@: * *
This requires use of the respip module.

If the IP address in an AAAA or A RR in the answer section of a response
matches the specified IP netblock, the specified action will apply.
*<action>* has generally the same semantics as that for
:ref:`access-control-tag-action`,
but there are some exceptions.

Actions for :ref:`response-ip` are different
from those for :ref:`local-zone` in that in case
of the former there is no point of such conditions as "the query matches it
but there is no local data".
Because of this difference, the semantics of
:ref:`response-ip` actions are modified or
simplified as follows: The *static*, *refuse*, *transparent*,
*typetransparent*, and *nodefault* actions are invalid for *response-ip*.
Using any of these will cause the configuration to be rejected as faulty.
The *deny* action is non-conditional, i.e. it always results in dropping
the corresponding query.
The resolution result before applying the *deny* action is still cached and
can be used for other queries.

@@[email protected]@response-ip-data@@: * <"resource record string">*
This requires use of the respip module.

This specifies the action data for
:ref:`response-ip` with action being to redirect
as specified by *<"resource record string">*.
*<"Resource record string">* is similar to that of
:ref:`access-control-tag-data`,
but it must be of either AAAA, A or CNAME types.
If the ** is an IPv6/IPv4 prefix, the record must be AAAA/A
respectively, unless it is a CNAME (which can be used for both versions of
IP netblocks).
If it is CNAME there must not be more than one
:ref:`response-ip-data` for the same
**.
Also, CNAME and other types of records must not coexist for the same
**, following the normal rules for CNAME records.
The textual domain name for the CNAME does not have to be explicitly
terminated with a dot (``"."``); the root name is assumed to be the origin
for the name.

@@[email protected]@response-ip-tag@@: * <"list of tags">*
This requires use of the respip module.

Assign tags to response **.
If the IP address in an AAAA or A RR in the answer section of a response
matches the specified **, the specified tags are assigned to
the IP address.
Then, if an :ref:`access-control-tag` is
defined for the client and it includes one of the tags for the response IP,
the corresponding
:ref:`access-control-tag-action`
will apply.
Tag matching rule is the same as that for
:ref:`access-control-tag` and
:ref:`local-zone`.
Unlike :ref:`local-zone-tag`,
:ref:`response-ip-tag` can be defined for an
** even if no :ref:`response-ip` is
defined for that netblock.
If multiple :ref:`response-ip-tag` options
are specified for the same ** in different statements, all but
the first will be ignored.
However, this will not be flagged as a configuration error, but the result
is probably not what was intended.

Actions specified in an
:ref:`access-control-tag-action`
that has a matching tag with
:ref:`response-ip-tag` can be those that are
"invalid" for :ref:`response-ip` listed above,
since
:ref:`access-control-tag-action`
can be shared with local zones.
For these actions, if they behave differently depending on whether local
data exists or not in case of local zones, the behavior for
:ref:`response-ip-data` will generally
result in NOERROR/NODATA instead of NXDOMAIN, since the
:ref:`response-ip` data are inherently type
specific, and non-existence of data does not indicate anything about the
existence or non-existence of the qname itself.
For example, if the matching tag action is static but there is no data for
the corresponding :ref:`response-ip`
configuration, then the result will be NOERROR/NODATA.
The only case where NXDOMAIN is returned is when an
:ref:`always_nxdomain`
action applies.

@@[email protected]@ratelimit@@: <number or 0>
Enable ratelimiting of queries sent to nameserver for performing recursion.
0 disables the feature.
This option is experimental at this time.

The ratelimit is in queries per second that are allowed.
More queries are turned away with an error (SERVFAIL).
Cached responses are not ratelimited by this setting.

This stops recursive floods, eg. random query names, but not spoofed
reflection floods.
The zone of the query is determined by examining the nameservers for it,
the zone name is used to keep track of the rate.
For example, 1000 may be a suitable value to stop the server from being
overloaded with random names, and keeps unbound from sending traffic to the
nameservers for those zones.

It is intended to count the number of queries towards the nameservers
for the zone, and keep those queries limited.
When there is a delegation that needs a lot of lookups, those are
charged in the counters for the destination, the target name, of
the NS records.
Since that is where the nameserver lookup queries are sent to.
That keeps the target, the victim domain, from having many queries.
With the :ref:`ratelimit-factor`, some
genuine queries that are also made to the target zone, can filter
through, and then end up in cache, where the genuine answers have
a chance to collect, keeping up service to some extent.

.. note:: Configured forwarders are excluded from ratelimiting.

Default: 0

@@[email protected]@ratelimit-size@@:
Give the size of the data structure in which the current ongoing rates are
kept track in.
In bytes or use m(mega), k(kilo), g(giga).
The ratelimit structure is small, so this data structure likely does not
need to be large.

Default: 4m

@@[email protected]@ratelimit-slabs@@:
Number of slabs in the ratelimit tracking data structure.
Slabs reduce lock contention by threads.
Must be set to a power of 2.
Setting (close) to the number of cpus is a fairly good setting.
If left unconfigured, it will be configured automatically to be a power of
2 close to the number of configured threads in multi-threaded environments.

Default: (unconfigured)

@@[email protected]@ratelimit-factor@@:
Set the amount of queries to rate limit when the limit is exceeded.
If set to 0, all queries are dropped for domains where the limit is
exceeded.
If set to another value, 1 in that number is allowed through to complete.
Default is 10, allowing 1/10 traffic to flow normally.
This can make ordinary queries complete (if repeatedly queried for), and
enter the cache, whilst also mitigating the traffic flow by the factor
given.

Default: 10

@@[email protected]@ratelimit-backoff@@:
If enabled, the ratelimit is treated as a hard failure instead of the
default maximum allowed constant rate.
When the limit is reached, traffic is ratelimited and demand continues to
be kept track of for a 2 second rate window.
No traffic is allowed, except for
:ref:ratelimit-factor, until demand
decreases below the configured ratelimit for a 2 second rate window.
Useful to set :ref:ratelimit to a suspicious
rate to aggressively limit unusually high traffic.

Default: no

@@[email protected]@ratelimit-for-domain@@: <number qps or 0>
Override the global :ref:ratelimit for an exact
match domain name with the listed number.
You can give this for any number of names.
For example, for a top-level-domain you may want to have a higher limit
than other names.
A value of 0 will disable ratelimiting for that domain.

@@[email protected]@ratelimit-below-domain@@: <number qps or 0>
Override the global :ref:ratelimit for a domain
name that ends in this name.
You can give this multiple times, it then describes different settings in
different parts of the namespace.
The closest matching suffix is used to determine the qps limit.
The rate for the exact matching domain name is not changed, use
:ref:ratelimit-for-domain to set
that, you might want to use different settings for a top-level-domain and
subdomains.
A value of 0 will disable ratelimiting for domain names that end in this
name.

@@[email protected]@ip-ratelimit@@: <number or 0>
Enable global ratelimiting of queries accepted per ip address.
This option is experimental at this time.
The ratelimit is in queries per second that are allowed.
More queries are completely dropped and will not receive a reply, SERVFAIL
or otherwise.
IP ratelimiting happens before looking in the cache.
This may be useful for mitigating amplification attacks.
Clients with a valid DNS Cookie will bypass the ratelimit.
If a ratelimit for such clients is still needed,
:ref:ip-ratelimit-cookie
can be used instead.

Default: 0 (disabled)

@@[email protected]@ip-ratelimit-cookie@@: <number or 0>
Enable global ratelimiting of queries accepted per IP address with a valid
DNS Cookie.
This option is experimental at this time.
The ratelimit is in queries per second that are allowed.
More queries are completely dropped and will not receive a reply, SERVFAIL
or otherwise.
IP ratelimiting happens before looking in the cache.
This option could be useful in combination with
:ref:allow_cookie, in an
attempt to mitigate other amplification attacks than UDP reflections (e.g.,
attacks targeting Unbound itself) which are already handled with DNS
Cookies.
If used, the value is suggested to be higher than
:ref:ip-ratelimit e.g., tenfold.

Default: 0 (disabled)

@@[email protected]@ip-ratelimit-size@@:
Give the size of the data structure in which the current ongoing rates are
kept track in.
In bytes or use m(mega), k(kilo), g(giga).
The IP ratelimit structure is small, so this data structure likely does not
need to be large.

Default: 4m

@@[email protected]@ip-ratelimit-slabs@@:
Number of slabs in the ip ratelimit tracking data structure.
Slabs reduce lock contention by threads.
Must be set to a power of 2.
Setting (close) to the number of cpus is a fairly good setting.
If left unconfigured, it will be configured automatically to be a power of
2 close to the number of configured threads in multi-threaded environments.

Default: (unconfigured)

@@[email protected]@ip-ratelimit-factor@@:
Set the amount of queries to rate limit when the limit is exceeded.
If set to 0, all queries are dropped for addresses where the limit is
exceeded.
If set to another value, 1 in that number is allowed through to complete.
Default is 10, allowing 1/10 traffic to flow normally.
This can make ordinary queries complete (if repeatedly queried for), and
enter the cache, whilst also mitigating the traffic flow by the factor
given.

Default: 10

@@[email protected]@ip-ratelimit-backoff@@:
If enabled, the rate limit is treated as a hard failure instead of the
default maximum allowed constant rate.
When the limit is reached, traffic is ratelimited and demand continues to
be kept track of for a 2 second rate window.
No traffic is allowed, except for
:ref:ip-ratelimit-factor, until demand
decreases below the configured ratelimit for a 2 second rate window.
Useful to set :ref:ip-ratelimit to a
suspicious rate to aggressively limit unusually high traffic.

Default: no

@@[email protected]@outbound-msg-retry@@:
The number of retries, per upstream nameserver in a delegation, that
Unbound will attempt in case a throwaway response is received.
No response (timeout) contributes to the retry counter.
If a forward/stub zone is used, this is the number of retries per
nameserver in the zone.

Default: 5

@@[email protected]@max-sent-count@@:
Hard limit on the number of outgoing queries Unbound will make while
resolving a name, making sure large NS sets do not loop.
Results in SERVFAIL when reached.
It resets on query restarts (e.g., CNAME) and referrals.

Default: 32

@@[email protected]@max-query-restarts@@:
Hard limit on the number of times Unbound is allowed to restart a query
upon encountering a CNAME record.
Results in SERVFAIL when reached.
This applies to chained CNAME records but not sporadic CNAME records that
could be encountered in the lifetime of the query's resolution effort.
When a CNAME chain concludes, the counter keeping track of this limit is
reset.
Changing this value needs caution as it can allow long CNAME chains to be
accepted, where Unbound needs to verify (resolve) each link individually.

Default: 11

@@[email protected]@iter-scrub-ns@@:
Limit on the number of NS records allowed in an rrset of type NS, from the
iterator scrubber.
This protects the internals of the resolver from overly large NS sets.

Default: 20

@@[email protected]@iter-scrub-cname@@:
Limit on the number of CNAME, DNAME records in an answer, from the iterator
scrubber.
This protects the internals of the resolver from overly long indirection
chains.
Clips off the remainder of the reply packet at that point.

Default: 11

@@[email protected]@iter-scrub-rrsig@@:
Limit on the number of RRSIGs allowed for an RRset, from the iterator
scrubber.
This protects against an overly large number of RRSIGs.
Clips off the remainder of the RRSIG list at that point.

Default: 8

@@[email protected]@max-global-quota@@:
Limit on the number of upstream queries sent out for an incoming query and
its subqueries from recursion.
It is not reset during the resolution.
When it is exceeded the query is failed and the lookup process stops.

Default: 200

@@[email protected]@iter-scrub-promiscuous@@:
Should the iterator scrubber remove promiscuous NS from positive answers.
This protects against poisonous contents, that could affect names in the
same zone as a spoofed packet.

Default: yes

@@[email protected]@val-validation-attempts@@:
Limit on the number of DNSSEC validation attempts for a query.
This protects against too large numbers of cryptographic operations,
like for a deep delegation chain.
This counts attempts to validate RRSIGs.
When it is exceeded, the query fails.

Default: 32

@@[email protected]@val-hash-attempts@@:
Limit on the number of DNSSEC hash attempts for a query.
This protects against too large numbers of cryptographic operations,
like for a deep delegation chain.
This counts DS hash attempts to match DNSKEYs.
When it is exceeded, the query fails.

Default: 32

@@[email protected]@fast-server-permil@@:
Specify how many times out of 1000 to pick from the set of fastest servers.
0 turns the feature off.
A value of 900 would pick from the fastest servers 90 percent of the time,
and would perform normal exploration of random servers for the remaining
time.
When :ref:prefetch is enabled (or
:ref:serve-expired), such prefetches are not
sped up, because there is no one waiting for it, and it presents a good
moment to perform server exploration.
The :ref:fast-server-num option can be
used to specify the size of the fastest servers set.

Default: 0

@@[email protected]@fast-server-num@@:
Set the number of servers that should be used for fast server selection.
Only use the fastest specified number of servers with the
:ref:fast-server-permil option, that
turns this on or off.

Default: 3

@@[email protected]@answer-cookie@@:
If enabled, Unbound will answer to requests containing DNS Cookies as
specified in RFC 7873 and RFC 9018.

Default: no

@@[email protected]@cookie-secret@@: "<128 bit hex string>"
Server's secret for DNS Cookie generation.
Useful to explicitly set for servers in an anycast deployment that need to
share the secret in order to verify each other's Server Cookies.
An example hex string would be "000102030405060708090a0b0c0d0e0f".

.. note::
    This option is ignored if a
    :ref:`cookie-secret-file` is present.
    In that case the secrets from that file are used in DNS Cookie
    calculations.

Default: 128 bits random secret generated at startup time

@@[email protected]@cookie-secret-file@@:
File from which the secrets are read used in DNS Cookie calculations.
When this file exists, the secrets in this file are used and the secret
specified by the
:ref:cookie-secret option is ignored.
Enable it by setting a filename, like
"/usr/local/etc/unbound_cookiesecrets.txt".
The content of this file must be manipulated with the
:ref:add_cookie_secret,
:ref:drop_cookie_secret and
:ref:activate_cookie_secret
commands to the :doc:unbound-control(8)</manpages/unbound-control> tool.
Please see that manpage on how to perform a safe cookie secret rollover.

Default: "" (disabled)

@@[email protected]@edns-client-string@@: * *
Include an EDNS0 option containing configured ASCII string in queries with
destination address matching the configured **.
This configuration option can be used multiple times.
The most specific match will be used.

@@[email protected]@edns-client-string-opcode@@:
EDNS0 option code for the
:ref:edns-client-string option, from 0
to 65535.
A value from the 'Reserved for Local/Experimental' range (65001-65534)
should be used.

Default: 65001

@@[email protected]@ede@@:
If enabled, Unbound will respond with Extended DNS Error codes
(:rfc:8914).
These EDEs provide additional information with a response mainly for, but
not limited to, DNS and DNSSEC errors.

When the :ref:`val-log-level` option is also
set to ``2``, responses with Extended DNS Errors concerning DNSSEC failures
will also contain a descriptive text message about the reason for the
failure.

Default: no

@@[email protected]@ede-serve-expired@@:
If enabled, Unbound will attach an Extended DNS Error (:rfc:8914) Code 3
- Stale Answer as EDNS0 option to the expired response.

.. note::
    :ref:`ede: yes` needs to be set as well for this to
    work.

Default: no

@@[email protected]@dns-error-reporting@@:
If enabled, Unbound will send DNS Error Reports (:rfc:9567).
The name servers need to express support by attaching the Report-Channel
EDNS0 option on their replies specifying the reporting agent for the zone.
Any errors encountered during resolution that would result in Unbound
generating an Extended DNS Error (:rfc:8914) will be reported to the
zone's reporting agent.

The :ref:`ede` option does not need to be enabled for
this to work.

It is advised that the
:ref:`qname-minimisation` option is also
enabled to increase privacy on the outgoing reports.

Default: no

.. _unbound.conf.remote:

Remote Control Options Copy Chapter

These options are part of the remote-control: section and are the
declarations for the remote control facility.

If this is enabled, the :doc:unbound-control(8)</manpages/unbound-control>
utility can be used to send commands to the running Unbound server.
The server uses these options to setup TLS security for the connection.
The :doc:unbound-control(8)</manpages/unbound-control> utility also reads
this remote-control: section for options.
To setup the correct self-signed certificates use the
unbound-control-setup(8) utility.

@@[email protected]@control-enable@@:
The option is used to enable remote control.
If turned off, the server does not listen for control commands.

Default: no

@@[email protected]@control-interface@@: **
Give IPv4 or IPv6 addresses or local socket path to listen on for control
commands.
If an interface name is used instead of an IP address, the list of IP
addresses on that interface are used.

By default localhost (``127.0.0.1`` and ``::1``) is listened to.
Use ``0.0.0.0`` and ``::0`` to listen to all interfaces.
If you change this and permissions have been dropped, you must restart the
server for the change to take effect.

If you set it to an absolute path, a unix domain socket is used.
This socket does not use the certificates and keys, so those files need not
be present.
To restrict access, Unbound sets permissions on the file to the user and
group that is configured, the access bits are set to allow the group
members to access the control socket file.
Put users that need to access the socket in the that group.
To restrict access further, create a directory to put the control socket in
and restrict access to that directory.

@@[email protected]@control-port@@: **
The port number to listen on for IPv4 or IPv6 control interfaces.

.. note::
    If you change this and permissions have been dropped, you must restart
    the server for the change to take effect.

Default: 8953

@@[email protected]@control-use-cert@@:
For localhost
:ref:control-interface you can
disable the use of TLS by setting this option to "no".
For local sockets, TLS is disabled and the value of this option is ignored.

Default: yes

@@[email protected]@server-key-file@@: **
Path to the server private key.
This file is generated by the
:doc:unbound-control-setup(8)</manpages/unbound-control> utility.
This file is used by the Unbound server, but not by
:doc:unbound-control(8)</manpages/unbound-control>.

Default: unbound_server.key

@@[email protected]@server-cert-file@@:
Path to the server self signed certificate.
This file is generated by the
:doc:unbound-control-setup(8)</manpages/unbound-control> utility.
This file is used by the Unbound server, and also by
:doc:unbound-control(8)</manpages/unbound-control>.

Default: unbound_server.pem

@@[email protected]@control-key-file@@: **
Path to the control client private key.
This file is generated by the
:doc:unbound-control-setup(8)</manpages/unbound-control> utility.
This file is used by :doc:unbound-control(8)</manpages/unbound-control>.

Default: unbound_control.key

@@[email protected]@control-cert-file@@:
Path to the control client certificate.
This certificate has to be signed with the server certificate.
This file is generated by the
:doc:unbound-control-setup(8)</manpages/unbound-control> utility.
This file is used by :doc:unbound-control(8)</manpages/unbound-control>.

Default: unbound_control.pem

.. _unbound.conf.stub:

Stub Zone Options Copy Chapter

These options are part of the stub-zone: section.

There may be multiple stub-zone: sections.
Each with a :ref:name and zero or more hostnames or
IP addresses.
For the stub zone this list of nameservers is used.
Class IN is assumed.
The servers should be authority servers, not recursors; Unbound performs the
recursive processing itself for stub zones.

The stub zone can be used to configure authoritative data to be used by the
resolver that cannot be accessed using the public internet servers.
This is useful for company-local data or private zones.
Setup an authoritative server on a different host (or different port).
Enter a config entry for Unbound with:

.. code-block:: text

stub-addr:

The Unbound resolver can then access the data, without referring to the public
internet for it.

This setup allows DNSSEC signed zones to be served by that authoritative
server, in which case a trusted key entry with the public key can be put in
config, so that Unbound can validate the data and set the AD bit on replies for
the private zone (authoritative servers do not set the AD bit).
This setup makes Unbound capable of answering queries for the private zone, and
can even set the AD bit ('authentic'), but the AA ('authoritative') bit is not
set on these replies.

Consider adding :ref:server statements for
:ref:domain-insecure and for
:ref:local-zone: \<name\> nodefault
for the zone if it is a locally served zone.
The :ref:domain-insecure option stops DNSSEC
from invalidating the zone.
The :ref:local-zone: nodefault (or
:ref:transparent) option makes the
(reverse-) zone bypass Unbound's filtering of :rfc:1918 zones.

@@[email protected]@name@@:
Name of the stub zone.
This is the full domain name of the zone.

@@[email protected]@stub-host@@:
Name of stub zone nameserver.
Is itself resolved before it is used.

.. caution::
    If the domain (or a subdomain) from this zone is used as the host, it
    will unavoidably introduce a circular dependency on retrieving the IP
    addresses of the name server.
    In that case, it is suggested to use
    :ref:`stub-addr` instead.
    Alternatively,
    :ref:`stub-first: yes` can also work
    around the circular dependency by trying resolution outside of this
    zone.
    However this has the caveat that it would allow escaping this zone when
    any resolution attempt fails within this zone.

To use a non-default port for DNS communication append ``'@'`` with the
port number.

If TLS is enabled, then you can append a ``'#'`` and a name, then it'll
check the TLS authentication certificates with that name.

If you combine the ``'@'`` and ``'#'``, the ``'@'`` comes first.
If only ``'#'`` is used the default port is the configured
:ref:`tls-port`.

@@[email protected]@stub-addr@@: **
IP address of stub zone nameserver.
Can be IPv4 or IPv6.

To use a non-default port for DNS communication append ``'@'`` with the
port number.

If TLS is enabled, then you can append a ``'#'`` and a name, then it'll
check the tls authentication certificates with that name.

If you combine the ``'@'`` and ``'#'``, the ``'@'`` comes first.
If only ``'#'`` is used the default port is the configured
:ref:`tls-port`.

@@[email protected]@stub-prime@@:
If enabled it performs NS set priming, which is similar to root hints,
where it starts using the list of nameservers currently published by the
zone.
Thus, if the hint list is slightly outdated, the resolver picks up a
correct list online.

Default: no

@@[email protected]@stub-first@@:
If enabled, a query is attempted without this stub section if it fails.
The data could not be retrieved and would have caused SERVFAIL because the
servers are unreachable, instead it is tried without this stub section.
This can lead to using less specific configured forward/stub/auth zones if
any, or end up to otherwise normal recursive resolution for that particular
query.

Default: no

@@[email protected]@stub-tls-upstream@@:
Enabled or disable whether the queries to this stub use TLS for transport.

Default: no

@@[email protected]@stub-ssl-upstream@@:
Alternate syntax for
:ref:stub-tls-upstream.

@@[email protected]@stub-tcp-upstream@@:
If it is set to "yes" then upstream queries use TCP only for transport
regardless of global flag :ref:tcp-upstream.

Default: no

@@[email protected]@stub-no-cache@@:
If enabled, data inside the stub is not cached.
This is useful when you want immediate changes to be visible.

Default: no

.. _unbound.conf.forward:

Forward Zone Options Copy Chapter

These options are part of the forward-zone: section.

There may be multiple forward-zone: sections.
Each with a :ref:name and zero or more hostnames
or IP addresses.
For the forward zone this list of nameservers is used to forward the queries
to.
The servers listed as :ref:forward-host
and :ref:forward-addr have to handle
further recursion for the query.
Thus, those servers are not authority servers, but are (just like Unbound is)
recursive servers too; Unbound does not perform recursion itself for the
forward zone, it lets the remote server do it.
Class IN is assumed.
CNAMEs are chased by Unbound itself, asking the remote server for every name in
the indirection chain, to protect the local cache from illegal indirect
referenced items.
A :ref:forward-zone entry with name
"." and a :ref:forward-addr target
will forward all queries to that other server (unless it can answer from the
cache).

@@[email protected]@name@@:
Name of the forward zone.
This is the full domain name of the zone.

@@[email protected]@forward-host@@:
Name of server to forward to.
Is itself resolved before it is used.

.. caution::
    If the domain (or a subdomain) from this zone is used as the host, it
    will unavoidably introduce a circular dependency on retrieving the IP
    addresses of the name server.
    In that case, it is suggested to use
    :ref:`forward-addr` instead.
    Alternatively,
    :ref:`forward-first: yes` can also
    work around the circular dependency by trying resolution outside of
    this zone.
    However this has the caveat that it would allow escaping this zone when
    any resolution attempt fails within this zone.

To use a non-default port for DNS communication append ``'@'`` with the
port number.

If TLS is enabled, then you can append a ``'#'`` and a name, then it'll
check the TLS authentication certificates with that name.

If you combine the ``'@'`` and ``'#'``, the ``'@'`` comes first.
If only ``'#'`` is used the default port is the configured
:ref:`tls-port`.

@@[email protected]@forward-addr@@: **
IP address of server to forward to.
Can be IPv4 or IPv6.

To use a non-default port for DNS communication append ``'@'`` with the
port number.

If TLS is enabled, then you can append a ``'#'`` and a name, then it'll
check the tls authentication certificates with that name.

If you combine the ``'@'`` and ``'#'``, the ``'@'`` comes first.
If only ``'#'`` is used the default port is the configured
:ref:`tls-port`.

At high verbosity it logs the TLS certificate, with TLS enabled.
If you leave out the ``'#'`` and auth name from the
:ref:`forward-addr`, any name is
accepted.
The cert must also match a CA from the
:ref:`tls-cert-bundle`.

@@[email protected]@forward-first@@:
If a forwarded query is met with a SERVFAIL error and this option is
enabled Unbound will fall back to less specific resolution.
This can lead to using less specific configured forward/stub/auth zones if
any, or end up to otherwise normal recursive resolution for that particular
query.

Default: no

@@[email protected]@forward-tls-upstream@@:
Enabled or disable whether the queries to this forwarder use TLS for
transport.
If you enable this, also configure a
:ref:tls-cert-bundle or use
:ref:tls-win-cert to load CA certs, otherwise
the connections cannot be authenticated.

Default: no

@@[email protected]@forward-ssl-upstream@@:
Alternate syntax for
:ref:forward-tls-upstream.

@@[email protected]@forward-tcp-upstream@@:
If it is set to "yes" then upstream queries use TCP only for transport
regardless of global flag :ref:tcp-upstream.

Default: no

@@[email protected]@forward-no-cache@@:
If enabled, data inside the forward is not cached.
This is useful when you want immediate changes to be visible.

Default: no

.. _unbound.conf.auth:

Authority Zone Options Copy Chapter

These options are part of the auth-zone: section.

Authority zones are configured with auth-zone:, and each one must have a
:ref:name.
There can be multiple ones, by listing multiple auth-zone section clauses,
each with a different name, pertaining to that part of the namespace.
The authority zone with the name closest to the name looked up is used.
Authority zones can be processed on two distinct, non-exclusive, configurable
stages.

With :ref:for-downstream: yes (default),
authority zones are processed after local-zones and before cache.
When used in this manner, Unbound responds like an authority server with no
further processing other than returning an answer from the zone contents.
A notable example, in this case, is CNAME records which are returned verbatim
to downstream clients without further resolution.

With :ref:for-upstream: yes (default),
authority zones are processed after the cache lookup, just before going to the
network to fetch information for recursion.
When used in this manner they provide a local copy of an authority server
that speeds up lookups for that data during resolving.

If both options are enabled (default), client queries for an authority zone are
answered authoritatively from Unbound, while internal queries that require data
from the authority zone consult the local zone data instead of going to the
network.

An interesting configuration is
:ref:for-downstream: no,
:ref:for-upstream: yes
that allows for hyperlocal behavior where both client and internal queries
consult the local zone data while resolving.
In this case, the aforementioned CNAME example will result in a thoroughly
resolved answer.

Authority zones can be read from a zonefile.
And can be kept updated via AXFR and IXFR.
After update the zonefile is rewritten.
The update mechanism uses the SOA timer values and performs SOA UDP queries to
detect zone changes.

If the update fetch fails, the timers in the SOA record are used to time
another fetch attempt.
Until the SOA expiry timer is reached.
Then the zone is expired.
When a zone is expired, queries are SERVFAIL, and any new serial number is
accepted from the primary (even if older), and if fallback is enabled, the
fallback activates to fetch from the upstream instead of the SERVFAIL.

@@[email protected]@name@@:
Name of the authority zone.

@@[email protected]@primary@@: **
Where to download a copy of the zone from, with AXFR and IXFR.
Multiple primaries can be specified.
They are all tried if one fails.

To use a non-default port for DNS communication append ``'@'`` with the
port number.

You can append a ``'#'`` and a name, then AXFR over TLS can be used and the
TLS authentication certificates will be checked with that name.

If you combine the ``'@'`` and ``'#'``, the ``'@'`` comes first.
If you point it at another Unbound instance, it would not work because that
does not support AXFR/IXFR for the zone, but if you used
:ref:`url` to download the zonefile as a text file
from a webserver that would work.

.. caution::
    If you specify the hostname, you cannot use the domain from the
    zonefile, because it may not have that when retrieving that data,
    instead use a plain IP address to avoid a circular dependency on
    retrieving that IP address.

@@[email protected]@master@@: **
Alternate syntax for :ref:primary.

@@[email protected]@url@@: **
Where to download a zonefile for the zone.
With HTTP or HTTPS.
An example for the url is:

.. code-block:: text

    http://www.example.com/example.org.zone

Multiple url statements can be given, they are tried in turn.

If only urls are given the SOA refresh timer is used to wait for making new
downloads.
If also primaries are listed, the primaries are first probed with UDP SOA
queries to see if the SOA serial number has changed, reducing the number of
downloads.
If none of the urls work, the primaries are tried with IXFR and AXFR.

For HTTPS, the :ref:`tls-cert-bundle` and
the hostname from the url are used to authenticate the connection.

If you specify a hostname in the URL, you cannot use the domain from the
zonefile, because it may not have that when retrieving that data, instead
use a plain IP address to avoid a circular dependency on retrieving that IP
address.

Avoid dependencies on name lookups by using a notation like
``"http://192.0.2.1/unbound-primaries/example.com.zone"``, with an explicit
IP address.

@@[email protected]@allow-notify@@: **
With :ref:allow-notify you can specify
additional sources of notifies.
When notified, the server attempts to first probe and then zone transfer.
If the notify is from a primary, it first attempts that primary.
Otherwise other primaries are attempted.
If there are no primaries, but only urls, the file is downloaded when
notified.

.. note::
    The primaries from :ref:`primary` and
    :ref:`url` statements are allowed notify by
    default.

@@[email protected]@fallback-enabled@@:
If enabled, Unbound falls back to querying the internet as a resolver for
this zone when lookups fail.
For example for DNSSEC validation failures.

Default: no

@@[email protected]@for-downstream@@:
If enabled, Unbound serves authority responses to downstream clients for
this zone.
This option makes Unbound behave, for the queries with names in this zone,
like one of the authority servers for that zone.

Turn it off if you want Unbound to provide recursion for the zone but have
a local copy of zone data.

If :ref:`for-downstream: no` and
:ref:`for-upstream: yes` are set, then
Unbound will DNSSEC validate the contents of the zone before serving the
zone contents to clients and store validation results in the cache.

Default: yes

@@[email protected]@for-upstream@@:
If enabled, Unbound fetches data from this data collection for answering
recursion queries.
Instead of sending queries over the internet to the authority servers for
this zone, it'll fetch the data directly from the zone data.

Turn it on when you want Unbound to provide recursion for downstream
clients, and use the zone data as a local copy to speed up lookups.

Default: yes

@@[email protected]@zonemd-check@@:
Enable this option to check ZONEMD records in the zone.
The ZONEMD record is a checksum over the zone data.
This includes glue in the zone and data from the zone file, and excludes
comments from the zone file.
When there is a DNSSEC chain of trust, DNSSEC signatures are checked too.

Default: no

@@[email protected]@zonemd-reject-absence@@:
Enable this option to reject the absence of the ZONEMD record.
Without it, when ZONEMD is not there it is not checked.

It is useful to enable for a non-DNSSEC signed zone where the operator
wants to require the verification of a ZONEMD, hence a missing ZONEMD is a
failure.

The action upon failure is controlled by the
:ref:`zonemd-permissive-mode` option,
for log only or also block the zone.

Without the option, absence of a ZONEMD is only a failure when the zone is
DNSSEC signed, and we have a trust anchor, and the DNSSEC verification of
the absence of the ZONEMD fails.
With the option enabled, the absence of a ZONEMD is always a failure, also
for nonDNSSEC signed zones.

Default: no

@@[email protected]@zonefile@@:
The filename where the zone is stored.
If not given then no zonefile is used.
If the file does not exist or is empty, Unbound will attempt to fetch zone
data (eg. from the primary servers).

@@[email protected]@max-transfer-size@@:
Number of bytes size of the maximum zone transfer size.
Larger transfers, over AXFR, IXFR and HTTP, are not allowed.
A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
or gigabytes (1024*1024 bytes in a megabyte).
The value 0 disables the feature.

Only consider for untrusted/misbehaving primaries that could hog resources
and bring down the resolver.

Default: 0

@@[email protected]@max-transfer-time@@:
Maximum time in milliseconds that a zone transfer is allowed to take from
the start.
The value 0 disables the feature.

Only consider for untrusted/misbehaving primaries that could hog resources
and bring down the resolver.

Default: 0

.. _unbound.conf.view:

View Options Copy Chapter

These options are part of the view: section.

There may be multiple view: sections.
Each with a :ref:name and zero or more
:ref:local-zone and
:ref:local-data options.
Views can also contain :ref:view-first,
:ref:response-ip,
:ref:response-ip-data and
:ref:local-data-ptr options.
View can be mapped to requests by specifying the view name in an
:ref:access-control-view option.
Options from matching views will override global options.
Global options will be used if no matching view is found, or when the matching
view does not have the option specified.

@@[email protected]@name@@:
Name of the view.
Must be unique.
This name is used in the
:ref:access-control-view option.

@@[email protected]@local-zone@@:
View specific local zone elements.
Has the same types and behaviour as the global
:ref:local-zone elements.
When there is at least one local-zone: specified and :ref:view-first: no is set, the default local-zones will be
added to this view.
Defaults can be disabled using the nodefault type.
When :ref:view-first: yes is set or when a
view does not have a :ref:local-zone, the
global :ref:local-zone will be used including
it's default zones.

@@[email protected]@local-data@@: ""
View specific local data elements.
Has the same behaviour as the global
:ref:local-data elements.

@@[email protected]@local-data-ptr@@: "IPaddr name"
View specific local-data-ptr elements.
Has the same behaviour as the global
:ref:local-data-ptr elements.

@@[email protected]@response-ip@@: * *
This requires use of the respip module.

Similar to :ref:`response-ip` but
only applies to this view.

@@[email protected]@response-ip-data@@: * <"resource record string">*
This requires use of the respip module.

Similar to :ref:`response-ip-data` but
only applies to this view.

@@[email protected]@view-first@@:
If enabled, it attempts to use the global
:ref:local-zone and
:ref:local-data if there is no match in the
view specific options.

Default: no

.. _unbound.conf.python:

Python Module Options Copy Chapter

These options are part of the python: section.

The python: section gives the settings for the python(1) script module.
This module acts like the iterator and validator modules do, on queries and
answers.
To enable the script module it has to be compiled into the daemon, and the word
python has to be put in the
:ref:module-config option (usually first, or
between the validator and iterator).
Multiple instances of the python module are supported by adding the word
python more than once.

If the :ref:chroot option is enabled, you should make
sure Python's library directory structure is bind mounted in the new root
environment, see mount(8).
Also the :ref:python-script path should
be specified as an absolute path relative to the new root, or as a relative
path to the working directory.

@@[email protected]@python-script@@: **
The script file to load.
Repeat this option for every python module instance added to the
:ref:module-config option.

.. _unbound.conf.dynlib:

Dynamic Library Module Options Copy Chapter

These options are part of the dynlib: section.

The dynlib: section gives the settings for the dynlib module.
This module is only a very small wrapper that allows dynamic modules to be
loaded on runtime instead of being compiled into the application.
To enable the dynlib module it has to be compiled into the daemon, and the word
dynlib has to be put in the
:ref:module-config option.
Multiple instances of dynamic libraries are supported by adding the word
dynlib more than once.

The :ref:dynlib-file path should be
specified as an absolute path relative to the new path set by
:ref:chroot, or as a relative path to the working
directory.

@@[email protected]@dynlib-file@@:
The dynamic library file to load.
Repeat this option for every dynlib module instance added to the
:ref:module-config option.

DNS64 Module Options Copy Chapter

These options are part of the server: section.

The dns64 module must be configured in the
:ref:module-config directive, e.g.:

.. code-block:: text

module-config: "dns64 validator iterator"

and be compiled into the daemon to be enabled.

.. note::
If combining the respip and dns64 modules, the respip module
needs to appear before the dns64 module in the
:ref:module-config
configuration option so that response IP and/or RPZ feeds can properly
filter responses regardless of DNS64 synthesis.

@@[email protected]@dns64-prefix@@: **
This sets the DNS64 prefix to use to synthesize AAAA records with.
It must be /96 or shorter.

Default: 64:ff9b::/96

@@[email protected]@dns64-synthall@@:
.. warning:: Debugging feature!

If enabled, synthesize all AAAA records despite the presence of actual AAAA
records.

Default: no

@@[email protected]@dns64-ignore-aaaa@@:
List domain for which the AAAA records are ignored and the A record is used
by DNS64 processing instead.
Can be entered multiple times, list a new domain for which it applies, one
per line.
Applies also to names underneath the name given.

NAT64 Options Copy Chapter

These options are part of the server: section.

NAT64 operation allows using a NAT64 prefix for outbound requests to IPv4-only
servers.

@@[email protected]@do-nat64@@:
Use NAT64 to reach IPv4-only servers.
Consider also enabling :ref:prefer-ip6
to prefer native IPv6 connections to nameservers.