1 PowerDNS Recursor Settings
2 ==========================
3 Each setting can appear on the command line, prefixed by '--', or in the configuration file.
4 The command line overrides the configuration file.
6 **Note**: Settings marked as 'Boolean' can either be set to an empty value, which means on, or to 'no' or 'off' which means off.
7 Anything else means on.
11 - ``serve-rfc1918`` on its own means: do serve those zones.
12 - ``serve-rfc1918=off`` or ``serve-rfc1918=no`` means: do not serve those zones.
13 - Anything else means: do serve those zones.
15 .. _setting-allow-from:
19 - IP ranges, separated by commas
20 - Default: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
22 Netmasks (both IPv4 and IPv6) that are allowed to use the server.
23 The default allows access only from :rfc:`1918` private IP addresses.
24 Due to the aggressive nature of the internet these days, it is highly recommended to not open up the recursor for the entire internet.
25 Questions from IP addresses not listed here are ignored and do not get an answer.
27 .. _setting-allow-from-file:
33 Like `allow-from`_, except reading from file.
34 Overrides the `allow-from`_ setting. To use this feature, supply one netmask per line, with optional comments preceded by a "#".
36 .. _setting-any-to-tcp:
43 Answer questions for the ANY type on UDP with a truncated packet that refers the remote server to TCP.
44 Useful for mitigating ANY reflection attacks.
46 .. _setting-api-config-dir:
50 .. versionadded:: 4.0.0
55 Directory where the REST API stores its configuration and zones.
61 .. versionadded:: 4.0.0
66 Static pre-shared authentication key for access to the REST API.
68 .. _setting-api-readonly:
72 .. versionchanged:: 4.2.0
73 This setting has been removed.
78 Disallow data modification through the REST API when set.
80 .. _setting-api-logfile:
84 .. versionchanged:: 4.2.0
85 This setting has been removed.
90 Location of the server logfile (used by the REST API).
92 .. _setting-auth-can-lower-ttl:
94 ``auth-can-lower-ttl``
95 ----------------------
99 Authoritative zones can transmit a TTL value that is lower than that specified in the parent zone.
100 This is called a 'delegation inconsistency'.
101 To follow :rfc:`RFC 2181 section 5.2<2181#section-5.2>` and :rfc:`5.4 <2181#section-5.4>` to the letter, enable this feature.
102 This will mean a slight deterioration of performance, and it will not solve any problems, but does make the recursor more standards compliant.
103 Not recommended unless you have to tick an 'RFC 2181 compliant' box.
105 .. _setting-auth-zones:
109 - Comma separated list of 'zonename=filename' pairs
111 Zones read from these files (in BIND format) are served authoritatively.
112 DNSSEC is not supported. Example:
116 auth-zones=example.org=/var/zones/example.org, powerdns.com=/var/zones/powerdns.com
118 .. _setting-carbon-interval:
125 If sending carbon updates, this is the interval between them in seconds.
128 .. _setting-carbon-namespace:
132 .. versionadded:: 4.2.0
136 Change the namespace or first string of the metric key. The default is pdns.
138 .. _setting-carbon-ourname:
144 If sending carbon updates, if set, this will override our hostname.
145 Be careful not to include any dots in this setting, unless you know what you are doing.
146 See :ref:`metricscarbon`.
148 .. _setting-carbon-instance:
152 .. versionadded:: 4.2.0
156 Change the instance or third string of the metric key. The default is recursor.
158 .. _setting-carbon-server:
164 If set to an IP or IPv6 address, will send all available metrics to this server via the carbon protocol, which is used by graphite and metronome. Moreover you can specify more than one server using a comma delimited list, ex: carbon-server=10.10.10.10,10.10.10.20.
165 You may specify an alternate port by appending :port, for example: ``127.0.0.1:2004``.
172 - Path to a Directory
174 If set, chroot to this directory for more security.
177 Make sure that ``/dev/log`` is available from within the chroot.
178 Logging will silently fail over time otherwise (on logrotate).
180 When using ``chroot``, all other paths (except for `config-dir`_) set in the configuration are relative to the new root.
182 When using ``chroot`` and the API (`webserver`_), `api-readonly`_ **must** be set and `api-config-dir`_ unset.
184 When running on a system where systemd manages services, ``chroot`` does not work out of the box, as PowerDNS cannot use the ``NOTIFY_SOCKET``.
185 Either do not ``chroot`` on these systems or set the 'Type' of this service to 'simple' instead of 'notify' (refer to the systemd documentation on how to modify unit-files).
187 .. _setting-client-tcp-timeout:
189 ``client-tcp-timeout``
190 ----------------------
194 Time to wait for data from TCP clients.
196 .. _setting-config-dir:
202 Location of configuration directory (``recursor.conf``).
203 Usually ``/etc/powerdns``, but this depends on ``SYSCONFDIR`` during compile-time.
205 .. _setting-config-name:
212 When running multiple recursors on the same server, read settings from :file:`recursor-{name}.conf`, this will also rename the binary image.
218 .. versionadded:: 4.1.0
223 Set CPU affinity for worker threads, asking the scheduler to run those threads on a single CPU, or a set of CPUs.
224 This parameter accepts a space separated list of thread-id=cpu-id, or thread-id=cpu-id-1,cpu-id-2,...,cpu-id-N.
225 For example, to make the worker thread 0 run on CPU id 0 and the worker thread 1 on CPUs 1 and 2::
229 The number of worker threads is determined by the :ref:`setting-threads` setting.
230 If :ref:`setting-pdns-distributes-queries` is set, an additional thread is started, assigned the id 0,
231 and is the only one listening on client sockets and accepting queries, distributing them to the other worker threads afterwards.
233 Starting with version 4.2.0, the thread handling the control channel, the webserver and other internal stuff has been assigned
234 id 0 and more than one distributor thread can be started using the :ref:`setting-distributor-threads` setting, so the distributor
235 threads if any are assigned id 1 and counting, and the other threads follow behind.
237 This parameter is only available on OS that provides the `pthread_setaffinity_np()` function.
246 .. versionchanged:: 4.0.0
248 Default is now "no", was "yes" before.
250 Operate in the background.
252 .. _setting-delegation-only:
256 - Domains, comma separated
258 Which domains we only accept delegations from (a Verisign special).
260 .. _setting-disable-packetcache:
262 ``disable-packetcache``
263 -----------------------
267 Turn off the packet cache. Useful when running with Lua scripts that can
270 .. _setting-disable-syslog:
277 Do not log to syslog, only to stdout.
278 Use this setting when running inside a supervisor that handles logging (like systemd).
279 **Note**: do not use this setting in combination with `daemon`_ as all logging will disappear.
281 .. _setting-distribution-load-factor:
283 ``distribution-load-factor``
284 ----------------------------
285 .. versionadded:: 4.1.12
290 If `pdns-distributes-queries`_ is set and this setting is set to another value
291 than 0, the distributor thread will use a bounded load-balancing algorithm while
292 distributing queries to worker threads, making sure that no thread is assigned
293 more queries than distribution-load-factor times the average number of queries
294 currently processed by all the workers.
295 For example, with a value of 1.25, no server should get more than 125 % of the
296 average load. This helps making sure that all the workers have roughly the same
297 share of queries, even if the incoming traffic is very skewed, with a larger
298 number of requests asking for the same qname.
300 .. _setting-distributor-threads:
302 ``distributor-threads``
303 -----------------------
304 .. versionadded:: 4.2.0
307 - Default: 1 if `pdns-distributes-queries`_ is set, 0 otherwise
309 If `pdns-distributes-queries`_ is set, spawn this number of distributor threads on startup. Distributor threads
310 handle incoming queries and distribute them to other threads based on a hash of the query, to maximize the cache hit
317 .. versionadded:: 4.0.0
319 - One of ``off``, ``process-no-validate``, ``process``, ``log-fail``, ``validate``, String
320 - Default: ``process-no-validate``
322 Set the mode for DNSSEC processing:
326 No DNSSEC processing whatsoever.
327 Ignore DO-bits in queries, don't request any DNSSEC information from authoritative servers.
328 This behaviour is similar to PowerDNS Recursor pre-4.0.
332 Respond with DNSSEC records to clients that ask for it, set the DO bit on all outgoing queries.
333 Don't do any validation.
337 Respond with DNSSEC records to clients that ask for it, set the DO bit on all outgoing queries.
338 Do validation for clients that request it (by means of the AD- bit or DO-bit in the query).
342 Similar behaviour to ``process``, but validate RRSIGs on responses and log bogus responses.
346 Full blown DNSSEC validation. Send SERVFAIL to clients on bogus responses.
348 .. _setting-dnssec-log-bogus:
355 Log every DNSSEC validation failure.
356 **Note**: This is not logged per-query but every time records are validated as Bogus.
358 .. _setting-dont-query:
362 - Netmasks, comma separated
363 - Default: 127.0.0.0/8, 10.0.0.0/8, 100.64.0.0/10, 169.254.0.0/16, 192.168.0.0/16, 172.16.0.0/12, ::1/128, fc00::/7, fe80::/10, 0.0.0.0/8, 192.0.0.0/24, 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, 240.0.0.0/4, ::/96, ::ffff:0:0/96, 100::/64, 2001:db8::/32
365 The DNS is a public database, but sometimes contains delegations to private IP addresses, like for example 127.0.0.1.
366 This can have odd effects, depending on your network, and may even be a security risk.
367 Therefore, the PowerDNS Recursor by default does not query private space IP addresses.
368 This setting can be used to expand or reduce the limitations.
370 Queries to addresses for zones as configured in any of the settings `forward-zones`_, `forward-zones-file`_ or `forward-zones-recurse`_ are performed regardless of these limitations.
372 .. _setting-ecs-add-for:
376 .. versionadded:: 4.2.0
378 - Comma separated list of netmasks
379 - Default: 0.0.0.0/0, ::, !127.0.0.0/8, !10.0.0.0/8, !100.64.0.0/10, !169.254.0.0/16, !192.168.0.0/16, !172.16.0.0/12, !::1/128, !fc00::/7, !fe80::/10
381 List of requestor netmasks for which the requestor IP Address should be used as the :rfc:`EDNS Client Subnet <7871>` for outgoing queries. Outgoing queries for requestors that do not match this list will use the `ecs-scope-zero-address`_ instead.
382 Valid incoming ECS values from `use-incoming-edns-subnet`_ are not replaced.
384 Regardless of the value of this setting, ECS values are only sent for outgoing queries matching the conditions in the `edns-subnet-whitelist`_ setting. This setting only controls the actual value being sent.
386 This defaults to not using the requestor address inside RFC1918 and similar "private" IP address spaces.
388 .. _setting-ecs-ipv4-bits:
392 .. versionadded:: 4.1.0
397 Number of bits of client IPv4 address to pass when sending EDNS Client Subnet address information.
399 .. _setting-ecs-ipv4-cache-bits:
401 ``ecs-ipv4-cache-bits``
403 .. versionadded:: 4.1.12
408 Maximum number of bits of client IPv4 address used by the authoritative server (as indicated by the EDNS Client Subnet scope in the answer) for an answer to be inserted into the query cache. This condition applies in conjunction with ``ecs-cache-limit-ttl``.
409 That is, only if both the limits apply, the record will not be cached.
411 .. _setting-ecs-ipv6-bits:
415 .. versionadded:: 4.1.0
420 Number of bits of client IPv6 address to pass when sending EDNS Client Subnet address information.
422 .. _setting-ecs-ipv6-cache-bits:
424 ``ecs-ipv6-cache-bits``
426 .. versionadded:: 4.1.12
431 Maximum number of bits of client IPv6 address used by the authoritative server (as indicated by the EDNS Client Subnet scope in the answer) for an answer to be inserted into the query cache. This condition applies in conjunction with ``ecs-cache-limit-ttl``.
432 That is, only if both the limits apply, the record will not be cached.
434 .. _setting-ecs-minimum-ttl-override:
436 ``ecs-minimum-ttl-override``
437 ----------------------------
439 - Default: 0 (disabled)
441 This setting artificially raises the TTLs of records in the ANSWER section of ECS-specific answers to be at least this long.
442 While this is a gross hack, and violates RFCs, under conditions of DoS, it may enable you to continue serving your customers.
443 Can be set at runtime using ``rec_control set-ecs-minimum-ttl 3600``.
445 .. _setting-ecs-cache-limit-ttl:
447 ``ecs-cache-limit-ttl``
448 -----------------------
449 .. versionadded:: 4.1.12
452 - Default: 0 (disabled)
454 The minimum TTL for an ECS-specific answer to be inserted into the query cache. This condition applies in conjunction with ``ecs-ipv4-cache-bits`` or ``ecs-ipv6-cache-bits``.
455 That is, only if both the limits apply, the record will not be cached.
457 .. _setting-ecs-scope-zero-address:
459 ``ecs-scope-zero-address``
460 --------------------------
461 .. versionadded:: 4.1.0
463 - IPv4 or IPv6 Address
466 The IP address sent via EDNS Client Subnet to authoritative servers listed in
467 `edns-subnet-whitelist`_ when `use-incoming-edns-subnet`_ is set and the query has
468 an ECS source prefix-length set to 0.
469 The default is to look for the first usable (not an ``any`` one) address in
470 `query-local-address`_ then `query-local-address6`_. If no suitable address is
471 found, the recursor fallbacks to sending 127.0.0.1.
473 .. _setting-edns-outgoing-bufsize:
475 ``edns-outgoing-bufsize``
476 -------------------------
477 .. versionchanged:: 4.2.0
478 Before 4.2.0, the default was 1680
485 1232 is the largest number of payload bytes that can fit in the smallest IPv6 packet.
486 IPv6 has a minimum MTU of 1280 bytes (:rfc:`RFC 8200, section 5 <8200#section-5>`), minus 40 bytes for the IPv6 header, minus 8 bytes for the UDP header gives 1232, the maximum payload size for the DNS response.
488 This is the value set for the EDNS0 buffer size in outgoing packets.
489 Lower this if you experience timeouts.
491 .. _setting-edns-subnet-whitelist:
493 ``edns-subnet-whitelist``
494 -------------------------
495 - Comma separated list of domain names and netmasks
498 List of netmasks and domains that :rfc:`EDNS Client Subnet <7871>` should be enabled for in outgoing queries.
500 For example, an EDNS Client Subnet option containing the address of the initial requestor (but see `ecs-add-for`_) will be added to an outgoing query sent to server 192.0.2.1 for domain X if 192.0.2.1 matches one of the supplied netmasks, or if X matches one of the supplied domains.
501 The initial requestor address will be truncated to 24 bits for IPv4 (see `ecs-ipv4-bits`_) and to 56 bits for IPv6 (see `ecs-ipv6-bits`_), as recommended in the privacy section of RFC 7871.
503 By default, this option is empty, meaning no EDNS Client Subnet information is sent.
505 .. _setting-entropy-source:
510 - Default: /dev/urandom
512 PowerDNS can read entropy from a (hardware) source.
513 This is used for generating random numbers which are very hard to predict.
514 Generally on UNIX platforms, this source will be ``/dev/urandom``, which will always supply random numbers, even if entropy is lacking.
515 Change to ``/dev/random`` if PowerDNS should block waiting for enough entropy to arrive.
517 .. _setting-etc-hosts-file:
522 - Default: /etc/hosts
524 The path to the /etc/hosts file, or equivalent.
525 This file can be used to serve data authoritatively using `export-etc-hosts`_.
527 .. _setting-export-etc-hosts:
534 If set, this flag will export the host names and IP addresses mentioned in ``/etc/hosts``.
536 .. _setting-export-etc-hosts-search-suffix:
538 ``export-etc-hosts-search-suffix``
539 ----------------------------------
542 If set, all hostnames in the `export-etc-hosts`_ file are loaded in canonical form, based on this suffix, unless the name contains a '.', in which case the name is unchanged.
543 So an entry called 'pc' with ``export-etc-hosts-search-suffix='home.com'`` will lead to the generation of 'pc.home.com' within the recursor.
544 An entry called 'server1.home' will be stored as 'server1.home', regardless of this setting.
546 .. _setting-forward-zones:
550 - 'zonename=IP' pairs, comma separated
552 Queries for zones listed here will be forwarded to the IP address listed. i.e.
556 forward-zones=example.org=203.0.113.210, powerdns.com=2001:DB8::BEEF:5
558 Multiple IP addresses can be specified and port numbers other than 53 can be configured:
562 forward-zones=example.org=203.0.113.210:5300;127.0.0.1, powerdns.com=127.0.0.1;198.51.100.10:530;[2001:DB8::1:3]:5300
564 Forwarded queries have the 'recursion desired' bit set to 0, meaning that this setting is intended to forward queries to authoritative servers.
566 **IMPORTANT**: When using DNSSEC validation (which is default), forwards to non-delegated (e.g. internal) zones that have a DNSSEC signed parent zone will validate as Bogus.
567 To prevent this, add a Negative Trust Anchor (NTA) for this zone in the `lua-config-file`_ with ``addNTA("your.zone", "A comment")``.
568 If this forwarded zone is signed, instead of adding NTA, add the DS record to the `lua-config-file`_.
569 See the :doc:`dnssec` information.
571 .. _setting-forward-zones-file:
573 ``forward-zones-file``
574 ----------------------
577 Same as `forward-zones`_, parsed from a file. Only 1 zone is allowed per line, specified as follows:
581 example.org=203.0.113.210, 192.0.2.4:5300
583 Zones prefixed with a '+' are forwarded with the recursion-desired bit set, for which see `forward-zones-recurse`_.
584 Default behaviour without '+' is as with `forward-zones`_.
586 .. versionchanged:: 4.0.0
588 Comments are allowed, everything behind '#' is ignored.
590 The DNSSEC notes from `forward-zones`_ apply here as well.
592 .. _setting-forward-zones-recurse:
594 ``forward-zones-recurse``
595 -------------------------
596 - 'zonename=IP' pairs, comma separated
598 Like regular `forward-zones`_, but forwarded queries have the 'recursion desired' bit set to 1, meaning that this setting is intended to forward queries to other recursive servers.
600 The DNSSEC notes from `forward-zones`_ apply here as well.
602 .. _setting-gettag-needs-edns-options:
604 ``gettag-needs-edns-options``
605 -----------------------------
606 .. versionadded:: 4.1.0
611 If set, EDNS options in incoming queries are extracted and passed to the :func:`gettag` hook in the ``ednsoptions`` table.
613 .. _setting-hint-file:
619 If set, the root-hints are read from this file. If unset, default root hints are used.
621 .. _setting-include-dir:
627 Directory to scan for additional config files. All files that end with .conf are loaded in order using ``POSIX`` as locale.
629 .. _setting-latency-statistic-size:
631 ``latency-statistic-size``
632 --------------------------
636 Indication of how many queries will be averaged to get the average latency reported by the 'qa-latency' metric.
638 .. _setting-local-address:
642 - IP addresses, comma separated
645 Local IPv4 or IPv6 addresses to bind to.
646 Addresses can also contain port numbers, for IPv4 specify like this: ``192.0.2.4:5300``, for IPv6: ``[::1]:5300``.
648 **Warning**: When binding to wildcard addresses, UNIX semantics mean that answers may not be sent from the address a query was received on.
649 It is highly recommended to bind to explicit addresses.
651 .. _setting-local-port:
658 Local port to bind to.
659 If an address in `local-address`_ does not have an explicit port, this port is used.
661 .. _setting-log-timestamp:
666 .. versionadded:: 4.1.0
671 When printing log lines to stdout, prefix them with timestamps.
672 Disable this if the process supervisor timestamps these lines already.
675 The systemd unit file supplied with the source code already disables timestamp printing
677 .. _setting-non-local-bind:
684 Bind to addresses even if one or more of the `local-address`_'s do not exist on this server.
685 Setting this option will enable the needed socket options to allow binding to non-local addresses.
686 This feature is intended to facilitate ip-failover setups, but it may also mask configuration issues and for this reason it is disabled by default.
688 .. _setting-loglevel:
692 - Integer between 0 and 9
696 Higher is more, more logging may destroy performance.
697 It is recommended not to set this below 3.
699 .. _setting-log-common-errors:
701 ``log-common-errors``
702 ---------------------
706 Some DNS errors occur rather frequently and are no cause for alarm.
710 .. versionadded:: 4.1.0
715 Log additions and removals to RPZ zones at Info (6) level instead of Debug (7).
717 .. _setting-logging-facility:
723 If set to a digit, logging is performed under this LOCAL facility.
725 Do not pass names like 'local0'!
727 .. _setting-lowercase-outgoing:
729 ``lowercase-outgoing``
730 ----------------------
734 Set to true to lowercase the outgoing queries.
735 When set to 'no' (the default) a query from a client using mixed case in the DNS labels (such as a user entering mixed-case names or `draft-vixie-dnsext-dns0x20-00 <http://tools.ietf.org/html/draft-vixie-dnsext-dns0x20-00>`_), PowerDNS preserves the case of the query.
736 Broken authoritative servers might give a wrong or broken answer on this encoding.
737 Setting ``lowercase-outgoing`` to 'yes' makes the PowerDNS Recursor lowercase all the labels in the query to the authoritative servers, but still return the proper case to the client requesting.
739 .. _setting-lua-config-file:
745 If set, and Lua support is compiled in, this will load an additional configuration file for newer features and more complicated setups.
746 See :doc:`lua-config/index` for the options that can be set in this file.
748 .. _setting-lua-dns-script:
755 Path to a lua file to manipulate the Recursor's answers. See :doc:`lua-scripting/index` for more information.
757 .. _setting-maintenance-interval:
759 ``lua-maintenance-interval``
760 ----------------------------
761 .. versionadded:: 4.1.4
767 The interval between calls to the Lua user defined `maintenance()` function in seconds.
768 See :ref:`hooks-maintenance-callback`
770 .. _setting-max-cache-bogus-ttl:
772 ``max-cache-bogus-ttl``
773 -----------------------
774 .. versionadded:: 4.2.0
779 Maximum number of seconds to cache an item in the DNS cache (negative or positive) if its DNSSEC validation failed, no matter what the original TTL specified, to reduce the impact of a broken domain.
781 .. _setting-max-cache-entries:
783 ``max-cache-entries``
784 ---------------------
788 Maximum number of DNS cache entries.
789 1 million per thread will generally suffice for most installations.
791 .. _setting-max-cache-ttl:
798 Maximum number of seconds to cache an item in the DNS cache, no matter what the original TTL specified.
800 .. versionchanged:: 4.1.0
802 The minimum value of this setting is 15. i.e. setting this to lower than 15 will make this value 15.
804 .. _setting-max-mthreads:
811 Maximum number of simultaneous MTasker threads.
813 .. _setting-max-packetcache-entries:
815 ``max-packetcache-entries``
816 ---------------------------
820 Maximum number of Packet Cache entries.
821 1 million per thread will generally suffice for most installations.
823 .. _setting-max-qperq:
830 The maximum number of outgoing queries that will be sent out during the resolution of a single client query.
831 This is used to limit endlessly chasing CNAME redirections.
833 .. _setting-max-negative-ttl:
840 A query for which there is authoritatively no answer is cached to quickly deny a record's existence later on, without putting a heavy load on the remote server.
841 In practice, caches can become saturated with hundreds of thousands of hosts which are tried only once.
842 This setting, which defaults to 3600 seconds, puts a maximum on the amount of time negative entries are cached.
844 .. _setting-max-recursion-depth:
846 ``max-recursion-depth``
847 -----------------------
851 Total maximum number of internal recursion calls the server may use to answer a single query.
853 The value of `stack-size`_ should be increased together with this one to prevent the stack from overflowing.
855 .. versionchanged:: 4.1.0
857 Before 4.1.0, this settings was unlimited.
859 .. _setting-max-tcp-clients:
866 Maximum number of simultaneous incoming TCP connections allowed.
868 .. _setting-max-tcp-per-client:
870 ``max-tcp-per-client``
871 ----------------------
873 - Default: 0 (unlimited)
875 Maximum number of simultaneous incoming TCP connections allowed per client (remote IP address).
877 .. _setting-max-tcp-queries-per-connection:
879 ``max-tcp-queries-per-connection``
880 ----------------------------------
881 .. versionadded:: 4.1.0
884 - Default: 0 (unlimited)
886 Maximum number of DNS queries in a TCP connection.
888 .. _setting-max-total-msec:
895 Total maximum number of milliseconds of wallclock time the server may use to answer a single query.
897 .. _setting-max-udp-queries-per-round:
899 ``max-udp-queries-per-round``
900 ----------------------------------
901 .. versionadded:: 4.1.4
906 Under heavy load the recursor might be busy processing incoming UDP queries for a long while before there is no more of these, and might therefore
907 neglect scheduling new ``mthreads``, handling responses from authoritative servers or responding to :doc:`rec_control <manpages/rec_control.1>`
909 This setting caps the maximum number of incoming UDP DNS queries processed in a single round of looping on ``recvmsg()`` after being woken up by the multiplexer, before
910 returning back to normal processing and handling other events.
912 .. _setting-minimum-ttl-override:
914 ``minimum-ttl-override``
915 ------------------------
917 - Default: 0 (disabled)
919 This setting artificially raises all TTLs to be at least this long.
920 While this is a gross hack, and violates RFCs, under conditions of DoS, it may enable you to continue serving your customers.
921 Can be set at runtime using ``rec_control set-minimum-ttl 3600``.
923 .. _setting-new-domain-tracking:
925 ``new-domain-tracking``
926 -----------------------
927 .. versionadded:: 4.2.0
930 - Default: no (disabled)
932 Whether to track newly observed domains, i.e. never seen before. This
933 is a probablistic algorithm, using a stable bloom filter to store
934 records of previously seen domains. When enabled for the first time,
935 all domains will appear to be newly observed, so the feature is best
936 left enabled for e.g. a week or longer before using the results. Note
937 that this feature is optional and must be enabled at compile-time,
938 thus it may not be available in all pre-built packages.
939 If protobuf is enabled and configured, then the newly observed domain
940 status will appear as a flag in Response messages.
942 .. _setting-new-domain-log:
946 .. versionadded:: 4.2.0
949 - Default: yes (enabled)
951 If a newly observed domain is detected, log that domain in the
952 recursor log file. The log line looks something like::
954 Jul 18 11:31:25 Newly observed domain nod=sdfoijdfio.com
956 .. _setting-new-domain-lookup:
958 ``new-domain-lookup``
959 ---------------------
960 .. versionadded:: 4.2.0
963 - Example: nod.powerdns.com
965 If a domain is specified, then each time a newly observed domain is
966 detected, the recursor will perform an A record lookup of "<newly
967 observed domain>.<lookup domain>". For example if 'new-domain-lookup'
968 is configured as 'nod.powerdns.com', and a new domain 'xyz123.tv' is
969 detected, then an A record lookup will be made for
970 'xyz123.tv.nod.powerdns.com'. This feature gives a way to share the
971 newly observed domain with partners, vendors or security teams. The
972 result of the DNS lookup will be ignored by the recursor.
974 .. _setting-new-domain-db-size:
976 ``new-domain-db-size``
977 ----------------------
978 .. versionadded:: 4.2.0
983 The default size of the stable bloom filter used to store previously
984 observed domains is 67108864. To change the number of cells, use this
985 setting. For each cell, the SBF uses 1 bit of memory, and one byte of
986 disk for the persistent file.
987 If there are already persistent files saved to disk, this setting will
988 have no effect unless you remove the existing files.
990 .. _setting-new-domain-history-dir:
992 ``new-domain-history-dir``
993 --------------------------
994 .. versionadded:: 4.2.0
998 This setting controls which directory is used to store the on-disk
999 cache of previously observed domains.
1001 The default depends on ``LOCALSTATEDIR`` when building the software.
1002 Usually this comes down to ``/var/lib/pdns-recursor/nod`` or ``/usr/local/var/lib/pdns-recursor/nod``).
1004 The newly observed domain feature uses a stable bloom filter to store
1005 a history of previously observed domains. The data structure is
1006 synchronized to disk every 10 minutes, and is also initialized from
1007 disk on startup. This ensures that previously observed domains are
1008 preserved across recursor restarts.
1009 If you change the new-domain-db-size setting, you must remove any files
1010 from this directory.
1012 .. _setting-new-domain-whitelist:
1014 ``new-domain-whitelist``
1015 ------------------------
1016 .. versionadded:: 4.2.0
1018 - List of Domain Names, comma separated
1019 - Example: xyz.com, abc.com
1021 This setting is a list of all domains (and implicitly all subdomains)
1022 that will never be considered a new domain. For example, if the domain
1023 'xyz123.tv' is in the list, then 'foo.bar.xyz123.tv' will never be
1024 considered a new domain. One use-case for the whitelist is to never
1025 reveal details of internal subdomains via the new-domain-lookup
1028 .. _setting-new-domain-pb-tag:
1030 ``new-domain-pb-tag``
1031 ---------------------
1032 .. versionadded:: 4.2.0
1037 If protobuf is configured, then this tag will be added to all protobuf response messages when
1038 a new domain is observed.
1040 .. _setting-network-timeout:
1047 Number of milliseconds to wait for a remote authoritative server to respond.
1049 .. _setting-nsec3-max-iterations:
1051 ``nsec3-max-iterations``
1052 ------------------------
1053 .. versionadded:: 4.1.0
1058 Maximum number of iterations allowed for an NSEC3 record.
1059 If an answer containing an NSEC3 record with more iterations is received, its DNSSEC validation status is treated as Insecure.
1061 .. _setting-packetcache-ttl:
1068 Maximum number of seconds to cache an item in the packet cache, no matter what the original TTL specified.
1070 .. _setting-packetcache-servfail-ttl:
1072 ``packetcache-servfail-ttl``
1073 ----------------------------
1077 Maximum number of seconds to cache a 'server failure' answer in the packet cache.
1079 .. versionchanged:: 4.0.0
1081 This setting's maximum is capped to `packetcache-ttl`_.
1082 i.e. setting ``packetcache-ttl=15`` and keeping ``packetcache-servfail-ttl`` at the default will lower ``packetcache-servfail-ttl`` to ``15``.
1084 .. _setting-pdns-distributes-queries:
1086 ``pdns-distributes-queries``
1087 ----------------------------
1091 If set, PowerDNS will have only 1 thread listening on client sockets, and distribute work by itself over threads by using a hash of the query,
1092 maximizing the cache hit ratio. Starting with version 4.2.0, more than one distributing thread can be started using the `distributor-threads`_
1094 Improves performance on Linux.
1096 .. _settting-public-suffix-list-file:
1098 ``public-suffix-list-file``
1099 ---------------------------
1100 .. versionadded:: 4.2.0
1105 Path to the Public Suffix List file, if any. If set, PowerDNS will try to load the Public Suffix List from this file instead of using the built-in list. The PSL is used to group the queries by relevant domain names when displaying the top queries.
1107 .. _setting-query-local-address:
1109 ``query-local-address``
1110 -----------------------
1111 - IPv4 Address, comma separated
1114 Send out local queries from this address, or addresses, by adding multiple addresses, increased spoofing resilience is achieved.
1116 .. _setting-query-local-address6:
1118 ``query-local-address6``
1119 ------------------------
1120 - IPv6 addresses, comma separated
1123 Send out local IPv6 queries from this address or addresses.
1124 Disabled by default, which also disables outgoing IPv6 support.
1135 .. _setting-reuseport:
1142 If ``SO_REUSEPORT`` support is available, allows multiple processes to open a listening socket on the same port.
1144 Since 4.1.0, when ``pdns-distributes-queries`` is set to false and ``reuseport`` is enabled, every thread will open a separate listening socket to let the kernel distribute the incoming queries, avoiding any thundering herd issue as well as the distributor thread being a bottleneck, thus leading to much higher performance on multi-core boxes.
1154 Specify which random number generator to use. Permissible choises are
1155 - auto - choose automatically
1156 - sodium - Use libsodium ``randombytes_uniform``
1157 - openssl - Use libcrypto ``RAND_bytes``
1158 - getrandom - Use libc getrandom, falls back to urandom if it does not really work
1159 - arc4random - Use BSD ``arc4random_uniform``
1160 - urandom - Use ``/dev/urandom``
1161 - kiss - Use simple settable deterministic RNG. **FOR TESTING PURPOSES ONLY!**
1164 Not all choises are available on all systems.
1166 .. _setting-root-nx-trust:
1173 If set, an NXDOMAIN from the root-servers will serve as a blanket NXDOMAIN for the entire TLD the query belonged to.
1174 The effect of this is far fewer queries to the root-servers.
1176 .. versionchanged:: 4.0.0
1178 Default is 'yes' now, was 'no' before 4.0.0
1180 .. _setting-security-poll-suffix:
1182 ``security-poll-suffix``
1183 ------------------------
1185 - Default: secpoll.powerdns.com.
1187 Domain name from which to query security update notifications.
1188 Setting this to an empty string disables secpoll.
1190 .. _setting-serve-rfc1918:
1197 This makes the server authoritatively aware of: ``10.in-addr.arpa``, ``168.192.in-addr.arpa``, ``16-31.172.in-addr.arpa``, which saves load on the AS112 servers.
1198 Individual parts of these zones can still be loaded or forwarded.
1200 .. _setting-server-down-max-fails:
1202 ``server-down-max-fails``
1203 -------------------------
1207 If a server has not responded in any way this many times in a row, no longer send it any queries for `server-down-throttle-time`_ seconds.
1208 Afterwards, we will try a new packet, and if that also gets no response at all, we again throttle for `server-down-throttle-time`_ seconds.
1209 Even a single response packet will drop the block.
1211 .. _setting-server-down-throttle-time:
1213 ``server-down-throttle-time``
1214 -----------------------------
1218 Throttle a server that has failed to respond `server-down-max-fails`_ times for this many seconds.
1220 .. _setting-server-id:
1225 - Default: The hostname of the server
1227 The reply given by The PowerDNS recursor to a query for 'id.server' with its hostname, useful for in clusters.
1228 When a query contains the :rfc:`NSID EDNS0 Option <5001>`, this value is returned in the response as the NSID value.
1230 This setting can be used to override the answer given to these queries.
1231 Set to "disabled" to disable NSID and 'id.server' answers.
1233 Query example (where 192.0.2.14 is your server):
1237 dig @192.0.2.14 CHAOS TXT id.server.
1238 dig @192.0.2.14 example.com IN A +nsid
1240 ``setgid``, ``setuid``
1241 ----------------------
1245 PowerDNS can change its user and group id after binding to its socket.
1246 Can be used for better :doc:`security <security>`.
1248 .. _setting-signature-inception-skew:
1250 ``signature-inception-skew``
1251 ----------------------------------
1252 .. versionadded:: 4.1.5
1257 Allow the signature inception to be off by this number of seconds. Negative values are not allowed.
1259 .. versionchanged:: 4.2.0
1261 Default is now 60, was 0 before.
1263 .. _setting-single-socket:
1270 Use only a single socket for outgoing queries.
1272 .. _setting-snmp-agent:
1276 .. versionadded:: 4.1.0
1281 If set to true and PowerDNS has been compiled with SNMP support, it will register as an SNMP agent to provide statistics and be able to send traps.
1283 .. _setting-snmp-master-socket:
1285 ``snmp-master-socket``
1286 ----------------------
1287 .. versionadded:: 4.1.0
1292 If not empty and ``snmp-agent`` is set to true, indicates how PowerDNS should contact the SNMP master to register as an SNMP agent.
1294 .. _setting-socket-dir:
1300 Where to store the control socket and pidfile.
1301 The default depends on ``LOCALSTATEDIR`` or the ``--with-socketdir`` setting when building (usually ``/var/run`` or ``/run``).
1303 When using `chroot`_ the default becomes to ``/``.
1305 ``socket-owner``, ``socket-group``, ``socket-mode``
1306 ---------------------------------------------------
1307 Owner, group and mode of the controlsocket.
1308 Owner and group can be specified by name, mode is in octal.
1310 .. _setting-spoof-nearmiss-max:
1312 ``spoof-nearmiss-max``
1313 ----------------------
1317 If set to non-zero, PowerDNS will assume it is being spoofed after seeing this many answers with the wrong id.
1319 .. _setting-stack-size:
1326 Size of the stack per thread.
1328 .. _setting-statistics-interval:
1330 ``statistics-interval``
1331 -----------------------
1332 .. versionadded:: 4.1.0
1337 Interval between logging statistical summary on recursor performance.
1340 .. _setting-stats-api-blacklist:
1342 ``stats-api-blacklist``
1343 -----------------------
1344 .. versionadded:: 4.2.0
1347 - Default: "cache-bytes, packetcache-bytes, ecs-v4-response-bits-*, ecs-v6-response-bits-*"
1349 A list of comma-separated statistic names, that are disabled when retrieving the complete list of statistics via the API for performance reasons.
1350 These statistics can still be retrieved individually by specifically asking for it.
1352 .. _setting-stats-carbon-blacklist:
1354 ``stats-carbon-blacklist``
1355 --------------------------
1356 .. versionadded:: 4.2.0
1359 - Default: "cache-bytes, packetcache-bytes, ecs-v4-response-bits-*, ecs-v6-response-bits-*"
1361 A list of comma-separated statistic names, that are prevented from being exported via carbon for performance reasons.
1363 .. _setting-stats-rec-control-blacklist:
1365 ``stats-rec-control-blacklist``
1366 -------------------------------
1367 .. versionadded:: 4.2.0
1370 - Default: "cache-bytes, packetcache-bytes, ecs-v4-response-bits-*, ecs-v6-response-bits-*"
1372 A list of comma-separated statistic names, that are disabled when retrieving the complete list of statistics via `rec_control get-all`, for performance reasons.
1373 These statistics can still be retrieved individually.
1375 .. _setting-stats-ringbuffer-entries:
1377 ``stats-ringbuffer-entries``
1378 ----------------------------
1382 Number of entries in the remotes ringbuffer, which keeps statistics on who is querying your server.
1383 Can be read out using ``rec_control top-remotes``.
1385 .. _setting-stats-snmp-blacklist:
1387 ``stats-snmp-blacklist``
1388 ------------------------
1389 .. versionadded:: 4.2.0
1392 - Default: "cache-bytes, packetcache-bytes, ecs-v4-response-bits-*, ecs-v6-response-bits-*"
1394 A list of comma-separated statistic names, that are prevented from being exported via SNMP, for performance reasons.
1396 .. _setting-tcp-fast-open:
1400 .. versionadded:: 4.1.0
1403 - Default: 0 (Disabled)
1405 Enable TCP Fast Open support, if available, on the listening sockets.
1406 The numerical value supplied is used as the queue size, 0 meaning disabled.
1408 .. _setting-threads:
1415 Spawn this number of threads on startup.
1424 If turned on, output impressive heaps of logging.
1425 May destroy performance under load.
1427 .. _setting-udp-source-port-min:
1429 ``udp-source-port-min``
1430 -----------------------
1431 .. versionadded:: 4.2.0
1436 This option sets the low limit of UDP port number to bind on.
1438 In combination with `udp-source-port-max`_ it configures the UDP
1439 port range to use. Port numbers are randomized within this range on
1440 initialization, and exceptions can be configured with `udp-source-port-avoid`_
1442 .. _setting-udp-source-port-max:
1444 ``udp-source-port-max``
1445 -----------------------
1446 .. versionadded:: 4.2.0
1451 This option sets the maximum limit of UDP port number to bind on.
1453 See `udp-source-port-min`_.
1455 .. _setting-udp-source-port-avoid:
1457 ``udp-source-port-avoid``
1458 -------------------------
1459 .. versionadded:: 4.2.0
1464 A list of comma-separated UDP port numbers to avoid when binding.
1467 See `udp-source-port-min`_.
1469 .. _setting-udp-truncation-threshold:
1471 ``udp-truncation-threshold``
1472 ----------------------------
1473 .. versionchanged:: 4.2.0
1474 Before 4.2.0, the default was 1680
1479 EDNS0 allows for large UDP response datagrams, which can potentially raise performance.
1480 Large responses however also have downsides in terms of reflection attacks.
1481 This setting limits the accepted size.
1482 Maximum value is 65535, but values above 4096 should probably not be attempted.
1484 To know why 1232, see the note at :ref:`setting-edns-outgoing-bufsize`.
1486 .. _setting-unique-response-tracking:
1488 ``unique-response-tracking``
1489 ----------------------------
1490 .. versionadded:: 4.2.0
1493 - Default: no (disabled)
1495 Whether to track unique DNS responses, i.e. never seen before combinations
1496 of the triplet (query name, query type, RR[rrname, rrtype, rrdata]).
1497 This can be useful for tracking potentially suspicious domains and
1498 behaviour, e.g. DNS fast-flux.
1499 If protobuf is enabled and configured, then the Protobuf Response message
1500 will contain a flag with udr set to true for each RR that is considered
1501 unique, i.e. never seen before.
1502 This feature uses a probabilistic data structure (stable bloom filter) to
1503 track unique responses, which can have false positives as well as false
1504 negatives, thus it is a best-effort feature. Increasing the number of cells
1505 in the SBF using the unique-response-db-size setting can reduce FPs and FNs.
1507 .. _setting-unique-response-log:
1509 ``unique-response-log``
1510 -----------------------
1511 .. versionadded:: 4.2.0
1514 - Default: no (disabled)
1516 Whether to log when a unique response is detected. The log line
1517 looks something like:
1519 Oct 24 12:11:27 Unique response observed: qname=foo.com qtype=A rrtype=AAAA rrname=foo.com rrcontent=1.2.3.4
1521 .. _setting-unique-response-db-size:
1523 ``unique-response-db-size``
1524 ---------------------------
1525 .. versionadded:: 4.2.0
1530 The default size of the stable bloom filter used to store previously
1531 observed responses is 67108864. To change the number of cells, use this
1532 setting. For each cell, the SBF uses 1 bit of memory, and one byte of
1533 disk for the persistent file.
1534 If there are already persistent files saved to disk, this setting will
1535 have no effect unless you remove the existing files.
1537 .. _setting-unique-response-history-dir:
1539 ``unique-response-history-dir``
1540 -------------------------------
1541 .. versionadded:: 4.2.0
1545 This setting controls which directory is used to store the on-disk
1546 cache of previously observed responses.
1548 The default depends on ``LOCALSTATEDIR`` when building the software.
1549 Usually this comes down to ``/var/lib/pdns-recursor/udr`` or ``/usr/local/var/lib/pdns-recursor/udr``).
1551 The newly observed domain feature uses a stable bloom filter to store
1552 a history of previously observed responses. The data structure is
1553 synchronized to disk every 10 minutes, and is also initialized from
1554 disk on startup. This ensures that previously observed responses are
1555 preserved across recursor restarts. If you change the
1556 unique-response-db-size, you must remove any files from this directory.
1558 .. _setting-unique-response-pb-tag:
1560 ``unique-response-pb-tag``
1561 --------------------------
1562 .. versionadded:: 4.2.0
1567 If protobuf is configured, then this tag will be added to all protobuf response messages when
1568 a unique DNS response is observed.
1570 .. _setting-use-incoming-edns-subnet:
1572 ``use-incoming-edns-subnet``
1573 ----------------------------
1577 Whether to process and pass along a received EDNS Client Subnet to authoritative servers.
1578 The ECS information will only be sent for netmasks and domains listed in `edns-subnet-whitelist`_ and will be truncated if the received scope exceeds `ecs-ipv4-bits`_ for IPv4 or `ecs-ipv6-bits`_ for IPv6.
1580 .. _setting-version:
1584 Print version of this binary. Useful for checking which version of the PowerDNS recursor is installed on a system.
1586 .. _setting-version-string:
1591 - Default: PowerDNS Recursor version number
1593 By default, PowerDNS replies to the 'version.bind' query with its version number.
1594 Security conscious users may wish to override the reply PowerDNS issues.
1596 .. _setting-webserver:
1603 Start the webserver (for REST API).
1605 .. _setting-webserver-address:
1607 ``webserver-address``
1608 ---------------------
1610 - Default: 127.0.0.1
1612 IP address for the webserver to listen on.
1614 .. _setting-webserver-allow-from:
1616 ``webserver-allow-from``
1617 ------------------------
1618 - IP addresses, comma separated
1619 - Default: 127.0.0.1,::1
1621 .. versionchanged:: 4.1.0
1623 Default is now 127.0.0.1,::1, was 0.0.0.0,::/0 before.
1625 These subnets are allowed to access the webserver.
1627 .. _setting-webserver-loglevel:
1629 ``webserver-loglevel``
1630 ----------------------
1631 .. versionadded:: 4.2.0
1633 - String, one of "none", "normal", "detailed"
1635 The amount of logging the webserver must do. "none" means no useful webserver information will be logged.
1636 When set to "normal", the webserver will log a line per request that should be familiar::
1638 [webserver] e235780e-a5cf-415e-9326-9d33383e739e 127.0.0.1:55376 "GET /api/v1/servers/localhost/bla HTTP/1.1" 404 196
1640 When set to "detailed", all information about the request and response are logged::
1642 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Request Details:
1643 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Headers:
1644 [webserver] e235780e-a5cf-415e-9326-9d33383e739e accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
1645 [webserver] e235780e-a5cf-415e-9326-9d33383e739e accept-encoding: gzip, deflate
1646 [webserver] e235780e-a5cf-415e-9326-9d33383e739e accept-language: en-US,en;q=0.5
1647 [webserver] e235780e-a5cf-415e-9326-9d33383e739e connection: keep-alive
1648 [webserver] e235780e-a5cf-415e-9326-9d33383e739e dnt: 1
1649 [webserver] e235780e-a5cf-415e-9326-9d33383e739e host: 127.0.0.1:8081
1650 [webserver] e235780e-a5cf-415e-9326-9d33383e739e upgrade-insecure-requests: 1
1651 [webserver] e235780e-a5cf-415e-9326-9d33383e739e user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:64.0) Gecko/20100101 Firefox/64.0
1652 [webserver] e235780e-a5cf-415e-9326-9d33383e739e No body
1653 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Response details:
1654 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Headers:
1655 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Connection: close
1656 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Content-Length: 49
1657 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Content-Type: text/html; charset=utf-8
1658 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Server: PowerDNS/0.0.15896.0.gaba8bab3ab
1659 [webserver] e235780e-a5cf-415e-9326-9d33383e739e Full body:
1660 [webserver] e235780e-a5cf-415e-9326-9d33383e739e <!html><title>Not Found</title><h1>Not Found</h1>
1661 [webserver] e235780e-a5cf-415e-9326-9d33383e739e 127.0.0.1:55376 "GET /api/v1/servers/localhost/bla HTTP/1.1" 404 196
1663 The value between the hooks is a UUID that is generated for each request. This can be used to find all lines related to a single request.
1666 The webserver logs these line on the NOTICE level. The :ref:`settings-loglevel` seting must be 5 or higher for these lines to end up in the log.
1668 .. _setting-webserver-password:
1670 ``webserver-password``
1671 ----------------------
1675 Password required to access the webserver.
1677 .. _setting-webserver-port:
1684 TCP port where the webserver should listen on.
1686 .. _setting-write-pid:
1693 If a PID file should be written to `socket-dir`_
1695 .. _setting-xpf-allow-from:
1699 .. versionadded:: 4.2.0
1701 - IP ranges, separated by commas
1705 This is an experimental implementation of `draft-bellis-dnsop-xpf <https://datatracker.ietf.org/doc/draft-bellis-dnsop-xpf/>`_.
1707 The server will trust XPF records found in queries sent from those netmasks (both IPv4 and IPv6),
1708 and will adjust queries' source and destination accordingly. This is especially useful when the recursor
1709 is placed behind a proxy like `dnsdist <https://dnsdist.org>`_.
1710 Note that the ref:`setting-allow-from` setting is still applied to the original source address, and thus access restriction
1711 should be done on the proxy.
1713 .. _setting-xpf-rr-code:
1717 .. versionadded:: 4.2.0
1723 This is an experimental implementation of `draft-bellis-dnsop-xpf <https://datatracker.ietf.org/doc/draft-bellis-dnsop-xpf/>`_.
1725 This option sets the resource record code to use for XPF records, as long as an official code has not been assigned to it.
1726 0 means that XPF is disabled.
projects / thirdparty / pdns.git / blob