3 Configuration Reference
4 =======================
6 This page lists all configuration options for dnsdist.
10 When an IPv6 IP:PORT combination is needed, the bracketed syntax from :rfc:`RFC 3986 <3986#section-3.2.2>` should be used.
11 e.g. "[2001:DB8:14::C0FF:FEE]:5300".
16 Within dnsdist several core object types exist:
18 * :class:`Server`: generated with :func:`newServer`, represents a downstream server
19 * :class:`ComboAddress`: represents an IP address and port
20 * :class:`DNSName`: represents a domain name
21 * :class:`NetmaskGroup`: represents a group of netmasks
22 * :class:`QPSLimiter`: implements a QPS-based filter
23 * :class:`SuffixMatchNode`: represents a group of domain suffixes for rapid testing of membership
24 * :class:`DNSHeader`: represents the header of a DNS packet, see :ref:`DNSHeader`
25 * :class:`ClientState`: sometimes also called Bind or Frontend, represents the addresses and ports dnsdist is listening on
27 The existence of most of these objects can mostly be ignored, unless you plan to write your own hooks and policies, but it helps to understand an expressions like:
31 getServer(0).order=12 -- set order of server 0 to 12
32 getServer(0):addPool("abuse") -- add this server to the abuse pool
34 The ``.`` means ``order`` is a data member, while the ``:`` means ``addPool`` is a member function.
39 .. function:: includeDirectory(path)
41 Include configuration files from ``path``.
43 :param str path: The directory to load configuration files from. Each file must end in ``.conf``.
45 .. function:: reloadAllCertificates()
47 .. versionadded:: 1.4.0
49 Reload all DNSCrypt and TLS certificates, along with their associated keys.
51 .. function:: setSyslogFacility(facility)
53 .. versionadded:: 1.4.0
55 Set the syslog logging facility to ``facility``.
57 :param int facility: The new facility as a numeric value. Defaults to LOG_DAEMON.
62 .. function:: addLocal(address[, options])
64 .. versionadded:: 1.2.0
66 .. versionchanged:: 1.3.0
67 Added ``cpus`` to the options.
69 Add to the list of listen addresses.
71 :param str address: The IP Address with an optional port to listen on.
72 The default port is 53.
73 :param table options: A table with key: value pairs with listen options.
77 * ``doTCP=true``: bool - Also bind on TCP on ``address``.
78 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
79 * ``tcpFastOpenSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
80 * ``interface=""``: str - Set the network interface to use.
81 * ``cpus={}``: table - Set the CPU affinity for this listener thread, asking the scheduler to run it on a single CPU id, or a set of CPU ids. This parameter is only available if the OS provides the pthread_setaffinity_np() function.
85 addLocal('0.0.0.0:5300', { doTCP=true, reusePort=true })
87 This will bind to both UDP and TCP on port 5300 with SO_REUSEPORT enabled.
89 .. function:: addLocal(address[[[,do_tcp], so_reuseport], tcp_fast_open_qsize])
93 Add to the list of addresses listened on.
95 :param str address: The IP Address with an optional port to listen on.
96 The default port is 53.
97 :param bool do_tcp: Also bind a TCP port on ``address``, defaults to true.
98 :param bool so_reuseport: Use ``SO_REUSEPORT`` if it is available, defaults to false
99 :param int tcp_fast_open_qsize: The size of the TCP Fast Open queue. Set to a number
100 higher than 0 to enable TCP Fast Open when available.
103 .. function:: addDOHLocal(address, certFile(s), keyFile(s) [, url [, options]])
105 .. versionadded:: 1.4.0
107 Listen on the specified address and TCP port for incoming DNS over HTTPS connections, presenting the specified X.509 certificate.
109 :param str address: The IP Address with an optional port to listen on.
110 The default port is 443.
111 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
112 :param str keyFile(s): The path to the private key file corresponding to the certificate, or a list of paths to such files, whose order should match the certFile(s) ones.
113 :param list url: A list of URLs to accept queries on. The default is /.
114 :param table options: A table with key: value pairs with listen options.
118 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
119 * ``tcpFastOpenSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
120 * ``interface=""``: str - Set the network interface to use.
121 * ``cpus={}``: table - Set the CPU affinity for this listener thread, asking the scheduler to run it on a single CPU id, or a set of CPU ids. This parameter is only available if the OS provides the pthread_setaffinity_np() function.
122 * ``idleTimeout=30``: int - Set the idle timeout, in seconds.
123 * ``ciphers``: str - The TLS ciphers to use, in OpenSSL format. Ciphers for TLS 1.3 must be specified via ``ciphersTLS13``.
124 * ``ciphersTLS13``: str - The TLS ciphers to use for TLS 1.3, in OpenSSL format.
126 .. function:: addTLSLocal(address, certFile(s), keyFile(s) [, options])
128 .. versionadded:: 1.3.0
129 .. versionchanged:: 1.3.1
130 ``certFile(s)`` and ``keyFile(s)`` parameters accept a list of files.
131 ``sessionTickets`` option added.
132 .. versionchanged:: 1.3.3
133 ``numberOfStoredSessions`` option added.
134 .. versionchanged:: 1.4.0
135 ``ciphersTLS13`` option added.
137 Listen on the specified address and TCP port for incoming DNS over TLS connections, presenting the specified X.509 certificate.
139 :param str address: The IP Address with an optional port to listen on.
140 The default port is 853.
141 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
142 :param str keyFile(s): The path to the private key file corresponding to the certificate, or a list of paths to such files, whose order should match the certFile(s) ones.
143 :param table options: A table with key: value pairs with listen options.
147 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
148 * ``tcpFastOpenSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
149 * ``interface=""``: str - Set the network interface to use.
150 * ``cpus={}``: table - Set the CPU affinity for this listener thread, asking the scheduler to run it on a single CPU id, or a set of CPU ids. This parameter is only available if the OS provides the pthread_setaffinity_np() function.
151 * ``provider``: str - The TLS library to use between GnuTLS and OpenSSL, if they were available and enabled at compilation time.
152 * ``ciphers``: str - The TLS ciphers to use. The exact format depends on the provider used. When the OpenSSL provder is used, ciphers for TLS 1.3 must be specified via ``ciphersTLS13``.
153 * ``ciphersTLS13``: str - The ciphers to use for TLS 1.3, when the OpenSSL provider is used. When the GnuTLS provider is used, ``ciphers`` applies regardless of the TLS protocol and this setting is not used.
154 * ``numberOfTicketsKeys``: int - The maximum number of tickets keys to keep in memory at the same time, if the provider supports it (GnuTLS doesn't, OpenSSL does). Only one key is marked as active and used to encrypt new tickets while the remaining ones can still be used to decrypt existing tickets after a rotation. Default to 5.
155 * ``ticketKeyFile``: str - The path to a file from where TLS tickets keys should be loaded, to support RFC 5077. These keys should be rotated often and never written to persistent storage to preserve forward secrecy. The default is to generate a random key. The OpenSSL provider supports several tickets keys to be able to decrypt existing sessions after the rotation, while the GnuTLS provider only supports one key.
156 * ``ticketsKeysRotationDelay``: int - Set the delay before the TLS tickets key is rotated, in seconds. Default is 43200 (12h).
157 * ``sessionTickets``: bool - Whether session resumption via session tickets is enabled. Default is true, meaning tickets are enabled.
158 * ``numberOfStoredSessions``: int - The maximum number of sessions kept in memory at the same time. At this time this is only supported by the OpenSSL provider, as stored sessions are not supported with the GnuTLS one. Default is 20480. Setting this value to 0 disables stored session entirely.
160 .. function:: setLocal(address[, options])
162 .. versionadded:: 1.2.0
164 Remove the list of listen addresses and add a new one.
166 :param str address: The IP Address with an optional port to listen on.
167 The default port is 53.
168 :param table options: A table with key: value pairs with listen options.
170 The options that can be set are the same as :func:`addLocal`.
172 .. function:: setLocal(address[[[,do_tcp], so_reuseport], tcp_fast_open_qsize])
174 .. deprecated:: 1.2.0
176 Remove the list of listen addresses and add a new one.
178 :param str address: The IP Address with an optional port to listen on.
179 The default port is 53.
180 :param bool do_tcp: Also bind a TCP port on ``address``, defaults to true.
181 :param bool so_reuseport: Use ``SO_REUSEPORT`` if it is available, defaults to false
182 :param int tcp_fast_open_qsize: The size of the TCP Fast Open queue. Set to a number
183 higher than 0 to enable TCP Fast Open when available.
186 Control Socket, Console and Webserver
187 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
189 .. function:: addConsoleACL(netmask)
191 .. versionadded:: 1.3.0
193 Add a netmask to the existing console ACL, allowing remote clients to connect to the console. Please make sure that encryption
194 has been enabled with :func:`setKey` before doing so. The default is to only allow 127.0.0.1/8 and ::1/128.
196 :param str netmask: A CIDR netmask, e.g. ``"192.0.2.0/24"``. Without a subnetmask, only the specific address is allowed.
198 .. function:: controlSocket(address)
200 Bind to ``addr`` and listen for a connection for the console. Since 1.3.0 only connections from local users are allowed
201 by default, :func:`addConsoleACL` and :func:`setConsoleACL` can be used to enable remote connections. Please make sure
202 that encryption has been enabled with :func:`setKey` before doing so. Enabling encryption is also strongly advised for
203 local connections, since not enabling it allows any local user to connect to the console.
205 :param str address: An IP address with optional port. By default, the port is 5199.
207 .. function:: inClientStartup()
209 Returns true while the console client is parsing the configuration.
211 .. function:: makeKey()
213 Generate and print an encryption key.
215 .. function:: setConsoleConnectionsLogging(enabled)
217 .. versionadded:: 1.2.0
219 Whether to log the opening and closing of console connections.
221 :param bool enabled: Default to true.
223 .. function:: setKey(key)
225 Use ``key`` as shared secret between the client and the server
227 :param str key: An encoded key, as generated by :func:`makeKey`
229 .. function:: setConsoleACL(netmasks)
231 .. versionadded:: 1.3.0
233 Remove the existing console ACL and add the netmasks from the table, allowing remote clients to connect to the console. Please make sure that encryption
234 has been enabled with :func:`setKey` before doing so.
236 :param {str} netmasks: A table of CIDR netmask, e.g. ``{"192.0.2.0/24", "2001:DB8:14::/56"}``. Without a subnetmask, only the specific address is allowed.
238 .. function:: showConsoleACL()
240 Print a list of all netmasks allowed to connect to the console.
242 .. function:: testCrypto()
244 Test the crypto code, will report errors when something is not ok.
246 .. function:: setConsoleOutputMaxMsgSize(size)
248 .. versionadded:: 1.3.3
250 Set the maximum size in bytes of a single console message, default set to 10 MB.
252 :param int size: The new maximum size.
254 Webserver configuration
255 ~~~~~~~~~~~~~~~~~~~~~~~
257 .. function:: webserver(listen_address, password[, apikey[, custom_headers]])
259 Launch the :doc:`../guides/webserver` with statistics and the API.
261 :param str listen_address: The IP address and Port to listen on
262 :param str password: The password required to access the webserver
263 :param str apikey: The key required to access the API
264 :param {[str]=str,...} custom_headers: Allows setting custom headers and removing the defaults
266 .. function:: setAPIWritable(allow [,dir])
268 Allow modifications via the API.
269 Optionally saving these changes to disk.
270 Modifications done via the API will not be written to the configuration by default and will not persist after a reload
272 :param bool allow: Set to true to allow modification through the API
273 :param str dir: A valid directory where the configuration files will be written by the API.
275 .. function:: setWebserverConfig(options)
277 .. versionadded:: 1.3.3
279 Setup webserver configuration. See :func:`webserver`.
281 :param table options: A table with key: value pairs with webserver options.
285 * ``password=newPassword``: string - Changes the API password
286 * ``apikey=newKey``: string - Changes the API Key (set to an empty string do disable it)
287 * ``custom_headers={[str]=str,...}``: map of string - Allows setting custom headers and removing the defaults.
292 .. function:: addACL(netmask)
294 Add a netmask to the existing ACL controlling which clients can send UDP and TCP queries. See :ref:`ACL` for more information.
296 :param str netmask: A CIDR netmask, e.g. ``"192.0.2.0/24"``. Without a subnetmask, only the specific address is allowed.
298 .. function:: setACL(netmasks)
300 Remove the existing ACL and add the netmasks from the table of those allowed to send UDP and TCP queries. See :ref:`ACL` for more information.
302 :param {str} netmasks: A table of CIDR netmask, e.g. ``{"192.0.2.0/24", "2001:DB8:14::/56"}``. Without a subnetmask, only the specific address is allowed.
304 .. function:: showACL()
306 Print a list of all netmasks allowed to send queries over UDP and TCP. See :ref:`ACL` for more information.
311 .. function:: setECSSourcePrefixV4(prefix)
313 When ``useClientSubnet`` in :func:`newServer` is set and dnsdist adds an EDNS Client Subnet Client option to the query, truncate the requestors IPv4 address to ``prefix`` bits
315 :param int prefix: The prefix length
317 .. function:: setECSSourcePrefixV6(prefix)
319 When ``useClientSubnet`` in :func:`newServer` is set and dnsdist adds an EDNS Client Subnet Client option to the query, truncate the requestor's IPv6 address to bits
321 :param int prefix: The prefix length
326 .. function:: setRingBuffersLockRetries(num)
328 .. versionadded:: 1.3.0
330 Set the number of shards to attempt to lock without blocking before giving up and simply blocking while waiting for the next shard to be available
332 :param int num: The maximum number of attempts. Defaults to 5 if there is more than one shard, 0 otherwise.
334 .. function:: setRingBuffersSize(num [, numberOfShards])
336 .. versionchanged:: 1.3.0
337 ``numberOfShards`` optional parameter added.
339 Set the capacity of the ringbuffers used for live traffic inspection to ``num``, and the number of shards to ``numberOfShards`` if specified.
341 :param int num: The maximum amount of queries to keep in the ringbuffer. Defaults to 10000
342 :param int numberOfShards: the number of shards to use to limit lock contention. Defaults to 1
347 .. function:: newServer(server_string)
348 newServer(server_table)
350 .. versionchanged:: 1.3.0
351 Added ``checkClass``, ``sockets`` and ``checkFunction`` to server_table.
353 .. versionchanged:: 1.4.0
354 Added ``checkTimeout`` and ``rise`` to server_table.
356 Add a new backend server. Call this function with either a string::
359 "IP:PORT" -- IP and PORT of the backend server
365 address="IP:PORT", -- IP and PORT of the backend server (mandatory)
366 id=STRING, -- Use a pre-defined UUID instead of a random one
367 qps=NUM, -- Limit the number of queries per second to NUM, when using the `firstAvailable` policy
368 order=NUM, -- The order of this server, used by the `leastOustanding` and `firstAvailable` policies
369 weight=NUM, -- The weight of this server, used by the `wrandom`, `whashed` and `chashed` policies, default: 1
370 -- Supported values are a minimum of 1, and a maximum of 2147483647.
371 pool=STRING|{STRING}, -- The pools this server belongs to (unset or empty string means default pool) as a string or table of strings
372 retries=NUM, -- The number of TCP connection attempts to the backend, for a given query
373 tcpConnectTimeout=NUM, -- The timeout (in seconds) of a TCP connection attempt
374 tcpSendTimeout=NUM, -- The timeout (in seconds) of a TCP write attempt
375 tcpRecvTimeout=NUM, -- The timeout (in seconds) of a TCP read attempt
376 tcpFastOpen=BOOL, -- Whether to enable TCP Fast Open
377 ipBindAddrNoPort=BOOL, -- Whether to enable IP_BIND_ADDRESS_NO_PORT if available, default: true
378 name=STRING, -- The name associated to this backend, for display purpose
379 checkClass=NUM, -- Use NUM as QCLASS in the health-check query, default: DNSClass.IN
380 checkName=STRING, -- Use STRING as QNAME in the health-check query, default: "a.root-servers.net."
381 checkType=STRING, -- Use STRING as QTYPE in the health-check query, default: "A"
382 checkFunction=FUNCTION,-- Use this function to dynamically set the QNAME, QTYPE and QCLASS to use in the health-check query (see :ref:`Healthcheck`)
383 checkTimeout=NUM, -- The timeout (in milliseconds) of a health-check query, default: 1000 (1s)
384 setCD=BOOL, -- Set the CD (Checking Disabled) flag in the health-check query, default: false
385 maxCheckFailures=NUM, -- Allow NUM check failures before declaring the backend down, default: 1
386 checkInterval=NUM -- The time in seconds between health checks
387 mustResolve=BOOL, -- Set to true when the health check MUST return a NOERROR RCODE and an answer
388 useClientSubnet=BOOL, -- Add the client's IP address in the EDNS Client Subnet option when forwarding the query to this backend
389 source=STRING, -- The source address or interface to use for queries to this backend, by default this is left to the kernel's address selection
390 -- The following formats are supported:
391 -- "address", e.g. "192.0.2.2"
392 -- "interface name", e.g. "eth0"
393 -- "address@interface", e.g. "192.0.2.2@eth0"
394 addXPF=NUM, -- Add the client's IP address and port to the query, along with the original destination address and port,
395 -- using the experimental XPF record from `draft-bellis-dnsop-xpf <https://datatracker.ietf.org/doc/draft-bellis-dnsop-xpf/>`_ and the specified option code. Default is disabled (0)
396 sockets=NUM, -- Number of sockets (and thus source ports) used toward the backend server, defaults to a single one
397 disableZeroScope=BOOL, -- Disable the EDNS Client Subnet 'zero scope' feature, which does a cache lookup for an answer valid for all subnets (ECS scope of 0) before adding ECS information to the query and doing the regular lookup
398 rise=NUM -- Require NUM consecutive successful checks before declaring the backend up, default: 1
401 :param str server_string: A simple IP:PORT string.
402 :param table server_table: A table with at least a 'name' key
404 .. function:: getServer(index) -> Server
406 Get a :class:`Server`
408 :param int index: The number of the server (as seen in :func:`showServers`).
409 :returns: The :class:`Server` object or nil
411 .. function:: getServers()
413 Returns a table with all defined servers.
415 .. function:: rmServer(index)
418 Remove a backend server.
420 :param int index: The number of the server (as seen in :func:`showServers`).
421 :param Server server: A :class:`Server` object as returned by e.g. :func:`getServer`.
425 A server object returned by :func:`getServer` can be manipulated with these functions.
429 This object represents a backend server. It has several methods.
431 .. method:: Server:addPool(pool)
433 Add this server to a pool.
435 :param str pool: The pool to add the server to
437 .. method:: Server:getName() -> string
439 Get the name of this server.
441 :returns: The name of the server, or an empty string if it does not have one
443 .. method:: Server:getNameWithAddr() -> string
445 Get the name plus IP address and port of the server
447 :returns: A string containing the server name if any plus the server address and port
449 .. method:: Server:getOutstanding() -> int
451 Get the number of outstanding queries for this server.
453 :returns: The number of outstanding queries
455 .. method:: Server:isUp() -> bool
457 Returns the up status of the server
459 :returns: true when the server is up, false otherwise
461 .. method:: Server:rmPool(pool)
463 Removes the server from the named pool
465 :param str pool: The pool to remove the server from
467 .. method:: Server:setAuto([status])
469 .. versionchanged:: 1.3.0
470 ``status`` optional parameter added.
472 Set the server in the default auto state.
473 This will enable health check queries that will set the server ``up`` and ``down`` appropriately.
475 :param bool status: Set the initial status of the server to ``up`` (true) or ``down`` (false) instead of using the last known status
477 .. method:: Server:setQPS(limit)
479 Limit the queries per second for this server.
481 :param int limit: The maximum number of queries per second
483 .. method:: Server:setDown()
485 Set the server in an ``DOWN`` state.
486 The server will not receive queries and the health checks are disabled
488 .. method:: Server:setUp()
490 Set the server in an ``UP`` state.
491 This server will still receive queries and health checks are disabled
493 Apart from the functions, a :class:`Server` object has these attributes:
495 .. attribute:: Server.name
497 The name of the server
499 .. attribute:: Server.upStatus
501 Whether or not this server is up or down
503 .. attribute:: Server.order
505 The order of the server
507 .. attribute:: Server.weight
509 The weight of the server
514 :class:`Server`\ s can be part of any number of pools.
515 Pools are automatically created when a server is added to a pool (with :func:`newServer`), or can be manually created with :func:`addPool`.
517 .. function:: addPool(name) -> ServerPool
519 Returns a :class:`ServerPool`.
521 :param string name: The name of the pool to create
523 .. function:: getPool(name) -> ServerPool
525 Returns a :class:`ServerPool` or nil.
527 :param string name: The name of the pool
529 .. function:: getPoolServers(name) -> [ Server ]
531 Returns a list of :class:`Server`\ s or nil.
533 :param string name: The name of the pool
535 .. function:: showPools()
537 Display the name, associated cache, server policy and associated servers for every pool.
539 .. class:: ServerPool
541 This represents the pool where zero or more servers are part of.
543 .. method:: ServerPool:getCache() -> PacketCache
545 Returns the :class:`PacketCache` for this pool or nil.
547 .. method:: ServerPool:getECS()
549 .. versionadded:: 1.3.0
551 Whether dnsdist will add EDNS Client Subnet information to the query before looking up into the cache,
552 when all servers from this pool are down. For more information see :meth:`ServerPool:setECS`.
554 .. method:: ServerPool:setCache(cache)
556 Adds ``cache`` as the pool's cache.
558 :param PacketCache cache: The new cache to add to the pool
560 .. method:: ServerPool:unsetCache()
562 Removes the cache from this pool.
564 .. method:: ServerPool:setECS()
566 .. versionadded:: 1.3.0
568 Set to true if dnsdist should add EDNS Client Subnet information to the query before looking up into the cache,
569 when all servers from this pool are down. If at least one server is up, the preference of the
570 selected server is used, this parameter is only useful if all the backends in this pool are down
571 and have EDNS Client Subnet enabled, since the queries in the cache will have been inserted with
572 ECS information. Default is false.
577 A Pool can have a packet cache to answer queries directly in stead of going to the backend.
578 See :doc:`../guides/cache` for a how to.
580 .. function:: newPacketCache(maxEntries[, maxTTL=86400[, minTTL=0[, temporaryFailureTTL=60[, staleTTL=60[, dontAge=false[, numberOfShards=1[, deferrableInsertLock=true[, maxNegativeTTL=3600[, parseECS=false]]]]]]]) -> PacketCache
582 .. versionchanged:: 1.3.0
583 ``numberOfShards`` and ``deferrableInsertLock`` parameters added.
585 .. versionchanged:: 1.3.1
586 ``maxNegativeTTL`` and ``parseECS`` parameters added.
588 .. deprecated:: 1.4.0
590 Creates a new :class:`PacketCache` with the settings specified.
592 :param int maxEntries: The maximum number of entries in this cache
593 :param int maxTTL: Cap the TTL for records to his number
594 :param int minTTL: Don't cache entries with a TTL lower than this
595 :param int temporaryFailureTTL: On a SERVFAIL or REFUSED from the backend, cache for this amount of seconds
596 :param int staleTTL: When the backend servers are not reachable, and global configuration ``setStaleCacheEntriesTTL`` is set appropriately, TTL that will be used when a stale cache entry is returned
597 :param bool dontAge: Don't reduce TTLs when serving from the cache. Use this when :program:`dnsdist` fronts a cluster of authoritative servers
598 :param int numberOfShards: Number of shards to divide the cache into, to reduce lock contention
599 :param bool deferrableInsertLock: Whether the cache should give up insertion if the lock is held by another thread, or simply wait to get the lock
600 :param int maxNegativeTTL: Cache a NXDomain or NoData answer from the backend for at most this amount of seconds, even if the TTL of the SOA record is higher
601 :param bool parseECS: Whether any EDNS Client Subnet option present in the query should be extracted and stored to be able to detect hash collisions involving queries with the same qname, qtype and qclass but a different incoming ECS value. Enabling this option adds a parsing cost and only makes sense if at least one backend might send different responses based on the ECS value, so it's disabled by default
603 .. function:: newPacketCache(maxEntries, [options]) -> PacketCache
605 .. versionadded:: 1.4.0
607 Creates a new :class:`PacketCache` with the settings specified.
609 :param int maxEntries: The maximum number of entries in this cache
613 * ``deferrableInsertLock=true``: bool - Whether the cache should give up insertion if the lock is held by another thread, or simply wait to get the lock.
614 * ``dontAge=false``: bool - Don't reduce TTLs when serving from the cache. Use this when :program:`dnsdist` fronts a cluster of authoritative servers.
615 * ``keepStaleData=false``: bool - Whether to suspend the removal of expired entries from the cache when there is no backend available in at least one of the pools using this cache.
616 * ``maxEntries``: int - The maximum number of entries in this cache.
617 * ``maxNegativeTTL=3600``: int - Cache a NXDomain or NoData answer from the backend for at most this amount of seconds, even if the TTL of the SOA record is higher.
618 * ``maxTTL=86400``: int - Cap the TTL for records to his number.
619 * ``minTTL=0``: int - Don't cache entries with a TTL lower than this.
620 * ``numberOfShards=1``: int - Number of shards to divide the cache into, to reduce lock contention.
621 * ``parseECS=false``: bool - Whether any EDNS Client Subnet option present in the query should be extracted and stored to be able to detect hash collisions involving queries with the same qname, qtype and qclass but a different incoming ECS value. Enabling this option adds a parsing cost and only makes sense if at least one backend might send different responses based on the ECS value, so it's disabled by default.
622 * ``staleTTL=60``: int - When the backend servers are not reachable, and global configuration ``setStaleCacheEntriesTTL`` is set appropriately, TTL that will be used when a stale cache entry is returned.
623 * ``temporaryFailureTTL=60``: int - On a SERVFAIL or REFUSED from the backend, cache for this amount of seconds..
625 .. class:: PacketCache
627 Represents a cache that can be part of :class:`ServerPool`.
629 .. method:: PacketCache:dump(fname)
631 .. versionadded:: 1.3.1
633 Dump a summary of the cache entries to a file.
635 :param str fname: The path to a file where the cache summary should be dumped. Note that if the target file already exists, it will not be overwritten.
637 .. method:: PacketCache:expunge(n)
639 Remove entries from the cache, leaving at most ``n`` entries
641 :param int n: Number of entries to keep
643 .. method:: PacketCache:expungeByName(name [, qtype=DNSQType.ANY[, suffixMatch=false]])
645 .. versionchanged:: 1.2.0
646 ``suffixMatch`` parameter added.
648 Remove entries matching ``name`` and type from the cache.
650 :param DNSName name: The name to expunge
651 :param int qtype: The type to expunge, can be a pre-defined :ref:`DNSQType`
652 :param bool suffixMatch: When set to true, remove al entries under ``name``
654 .. method:: PacketCache:getStats()
656 .. versionadded:: 1.4.0
658 Return the cache stats (number of entries, hits, misses, deferred lookups, deferred inserts, lookup collisions, insert collisions and TTL too shorts) as a Lua table.
660 .. method:: PacketCache:isFull() -> bool
662 Return true if the cache has reached the maximum number of entries.
664 .. method:: PacketCache:printStats()
666 Print the cache stats (number of entries, hits, misses, deferred lookups, deferred inserts, lookup collisions, insert collisions and TTL too shorts).
668 .. method:: PacketCache:purgeExpired(n)
670 Remove expired entries from the cache until there is at most ``n`` entries remaining in the cache.
672 :param int n: Number of entries to keep
674 .. method:: PacketCache:toString() -> string
676 Return the number of entries in the Packet Cache, and the maximum number of entries
681 Also called frontend or bind, the Client State object returned by :func:`getBind` and listed with :func:`showBinds` represents an address and port dnsdist is listening on.
683 .. function:: getBind(index) -> ClientState
685 Return a :class:`ClientState` object.
687 :param int index: The object index
689 ClientState functions
690 ~~~~~~~~~~~~~~~~~~~~~
692 .. class:: ClientState
694 This object represents an address and port dnsdist is listening on. When ``reuseport`` is in use, several ClientState objects can be present for the same address and port.
696 .. method:: ClientState:attachFilter(filter)
698 Attach a BPF filter to this frontend.
700 :param BPFFilter filter: The filter to attach to this frontend
702 .. method:: ClientState:detachFilter()
704 Remove the BPF filter associated to this frontend, if any.
706 .. method:: ClientState:toString() -> string
708 Return the address and port this frontend is listening on.
710 :returns: The address and port this frontend is listening on
712 .. attribute:: ClientState.muted
714 If set to true, queries received on this frontend will be normally processed and sent to a backend if needed, but no response will be ever be sent to the client over UDP. TCP queries are processed normally and responses sent to the client.
716 Status, Statistics and More
717 ---------------------------
719 .. function:: dumpStats()
721 Print all statistics dnsdist gathers
723 .. function:: getDOHFrontend(idx)
725 .. versionadded:: 1.4.0
727 Return the DOHFrontend object for the DNS over HTTPS bind of index ``idx``.
729 .. function:: getTLSContext(idx)
731 .. versionadded:: 1.3.0
733 Return the TLSContext object for the context of index ``idx``.
735 .. function:: getTLSFrontend(idx)
737 .. versionadded:: 1.3.1
739 Return the TLSFrontend object for the TLS bind of index ``idx``.
741 .. function:: grepq(selector[, num])
742 grepq(selectors[, num])
744 Prints the last ``num`` queries matching ``selector`` or ``selectors``.
748 * a netmask (e.g. '192.0.2.0/24')
749 * a DNS name (e.g. 'dnsdist.org')
750 * a response time (e.g. '100ms')
752 :param str selector: Select queries based on this property.
753 :param {str} selectors: A lua table of selectors. Only queries matching all selectors are shown
754 :param int num: Show a maximum of ``num`` recent queries, default is 10.
756 .. function:: setVerboseHealthChecks(verbose)
758 Set whether health check errors should be logged. This is turned off by default.
760 :param bool verbose: Set to true if you want to enable health check errors logging
762 .. function:: showBinds()
764 Print a list of all the current addresses and ports dnsdist is listening on, also called ``frontends``
766 .. function:: showDOHFrontends()
768 .. versionadded:: 1.4.0
770 Print the list of all availables DNS over HTTPS frontends.
772 .. function:: showResponseLatency()
774 Show a plot of the response time latency distribution
776 .. function:: showServers([options])
778 .. versionchanged:: 1.4.0
779 ``options`` optional parameter added
781 This function shows all backend servers currently configured and some statistics.
782 These statics have the following fields:
784 * ``#`` - The number of the server, can be used as the argument for :func:`getServer`
785 * ``UUID`` - The UUID of the backend. Can be set with the ``id`` option of :func:`newServer`
786 * ``Address`` - The IP address and port of the server
787 * ``State`` - The current state of the server
788 * ``Qps`` - Current number of queries per second
789 * ``Qlim`` - Configured maximum number of queries per second
790 * ``Ord`` - The order number of the server
791 * ``Wt`` - The weight of the server
792 * ``Queries`` - Total amount of queries sent to this server
793 * ``Drops`` - Number of queries that were dropped by this server
794 * ``Drate`` - Number of queries dropped per second by this server
795 * ``Lat`` - The latency of this server in milliseconds
796 * ``Pools`` - The pools this server belongs to
798 :param table options: A table with key: value pairs with display options.
802 * ``showUUIDs=false``: bool - Whether to display the UUIDs, defaults to false.
804 .. function:: showTCPStats()
806 Show some statistics regarding TCP
808 .. function:: showTLSContexts()
810 .. versionadded:: 1.3.0
812 Print the list of all availables DNS over TLS contexts.
814 .. function:: showVersion()
816 Print the version of dnsdist
818 .. function:: topBandwidth([num])
820 Print the top ``num`` clients that consume the most bandwidth.
822 :param int num: Number to show, defaults to 10.
824 .. function:: topClients([num])
826 Print the top ``num`` clients sending the most queries over length of ringbuffer
828 :param int num: Number to show, defaults to 10.
830 .. function:: topQueries([num[, labels]])
832 Print the ``num`` most popular QNAMEs from queries.
833 Optionally grouped by the rightmost ``labels`` DNS labels.
835 :param int num: Number to show, defaults to 10
836 :param int label: Number of labels to cut down to
838 .. function:: topResponses([num[, rcode[, labels]]])
840 Print the ``num`` most seen responses with an RCODE of ``rcode``.
841 Optionally grouped by the rightmost ``labels`` DNS labels.
843 :param int num: Number to show, defaults to 10
844 :param int rcode: :ref:`Response code <DNSRCode>`, defaults to 0 (No Error)
845 :param int label: Number of labels to cut down to
847 .. function:: topSlow([num[, limit[, labels]]])
849 Print the ``num`` slowest queries that are slower than ``limit`` milliseconds.
850 Optionally grouped by the rightmost ``labels`` DNS labels.
852 :param int num: Number to show, defaults to 10
853 :param int limit: Show queries slower than this amount of milliseconds, defaults to 2000
854 :param int label: Number of labels to cut down to
861 .. function:: addDynBlocks(addresses, message[, seconds=10[, action]])
863 .. versionchanged:: 1.2.0
864 ``action`` parameter added.
866 Block a set of addresses with ``message`` for (optionally) a number of seconds.
867 The default number of seconds to block for is 10.
869 :param addresses: set of Addresses as returned by an exceed function
870 :param string message: The message to show next to the blocks
871 :param int seconds: The number of seconds this block to expire
872 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to DNSAction.None, meaning the one set with :func:`setDynBlocksAction` is used)
874 Please see the documentation for :func:`setDynBlocksAction` to confirm which actions are supported by the action paramater.
876 .. function:: clearDynBlocks()
878 Remove all current dynamic blocks.
880 .. function:: showDynBlocks()
882 List all dynamic blocks in effect.
884 .. function:: setDynBlocksAction(action)
886 .. versionchanged:: 1.3.3
887 ``DNSAction.NXDomain`` action added.
889 Set which action is performed when a query is blocked.
890 Only DNSAction.Drop (the default), DNSAction.NoOp, DNSAction.NXDomain, DNSAction.Refused, DNSAction.Truncate and DNSAction.NoRecurse are supported.
894 Getting addresses that exceeded parameters
895 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
897 .. function:: exceedServFails(rate, seconds)
899 Get set of addresses that exceed ``rate`` servfails/s over ``seconds`` seconds
901 :param int rate: Number of Servfails per second to exceed
902 :param int seconds: Number of seconds the rate has been exceeded
904 .. function:: exceedNXDOMAINs(rate, seconds)
906 get set of addresses that exceed ``rate`` NXDOMAIN/s over ``seconds`` seconds
908 :param int rate: Number of NXDOMAIN per second to exceed
909 :param int seconds: Number of seconds the rate has been exceeded
911 .. function:: exceedRespByterate(rate, seconds)
913 get set of addresses that exceeded ``rate`` bytes/s answers over ``seconds`` seconds
915 :param int rate: Number of bytes per second to exceed
916 :param int seconds: Number of seconds the rate has been exceeded
918 .. function:: exceedQRate(rate, seconds)
920 Get set of address that exceed ``rate`` queries/s over ``seconds`` seconds
922 :param int rate: Number of queries per second to exceed
923 :param int seconds: Number of seconds the rate has been exceeded
925 .. function:: exceedQTypeRate(type, rate, seconds)
927 Get set of address that exceed ``rate`` queries/s for queries of QType ``type`` over ``seconds`` seconds
929 :param int type: QType
930 :param int rate: Number of QType queries per second to exceed
931 :param int seconds: Number of seconds the rate has been exceeded
936 Instead of using several `exceed*()` lines, dnsdist 1.3.0 introduced a new `DynBlockRulesGroup` object
937 which can be used to group dynamic block rules.
939 See :doc:`../guides/dynblocks` for more information about the case where using a `DynBlockRulesGroup` might be
940 faster than the existing rules.
942 .. function:: dynBlockRulesGroup() -> DynBlockRulesGroup
944 .. versionadded:: 1.3.0
946 Creates a new :class:`DynBlockRulesGroup` object.
948 .. class:: DynBlockRulesGroup
950 Represents a group of dynamic block rules.
952 .. method:: DynBlockRulesGroup:setQueryRate(rate, seconds, reason, blockingTime [, action [, warningRate]])
954 .. versionchanged:: 1.3.3
955 ``warningRate`` parameter added.
957 Adds a query rate-limiting rule, equivalent to:
959 addDynBlocks(exceedQRate(rate, seconds), reason, blockingTime, action)
962 :param int rate: Number of queries per second to exceed
963 :param int seconds: Number of seconds the rate has been exceeded
964 :param string reason: The message to show next to the blocks
965 :param int blockingTime: The number of seconds this block to expire
966 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
967 :param int warningRate: If set to a non-zero value, the rate above which a warning message will be issued and a no-op block inserted
969 .. method:: DynBlockRulesGroup:setRCodeRate(rcode, rate, seconds, reason, blockingTime [, action [, warningRate]])
971 .. versionchanged:: 1.3.3
972 ``warningRate`` parameter added.
974 Adds a rate-limiting rule for responses of code ``rcode``, equivalent to:
976 addDynBlocks(exceedServfails(rcode, rate, seconds), reason, blockingTime, action)
979 :param int rcode: The response code
980 :param int rate: Number of responses per second to exceed
981 :param int seconds: Number of seconds the rate has been exceeded
982 :param string reason: The message to show next to the blocks
983 :param int blockingTime: The number of seconds this block to expire
984 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
985 :param int warningRate: If set to a non-zero value, the rate above which a warning message will be issued and a no-op block inserted
987 .. method:: DynBlockRulesGroup:setQTypeRate(qtype, rate, seconds, reason, blockingTime [, action [, warningRate]])
989 .. versionchanged:: 1.3.3
990 ``warningRate`` parameter added.
992 Adds a rate-limiting rule for queries of type ``qtype``, equivalent to:
994 addDynBlocks(exceedQTypeRate(type, rate, seconds), reason, blockingTime, action)
997 :param int qtype: The qtype
998 :param int rate: Number of queries per second to exceed
999 :param int seconds: Number of seconds the rate has been exceeded
1000 :param string reason: The message to show next to the blocks
1001 :param int blockingTime: The number of seconds this block to expire
1002 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
1003 :param int warningRate: If set to a non-zero value, the rate above which a warning message will be issued and a no-op block inserted
1005 .. method:: DynBlockRulesGroup:setResponseByteRate(rate, seconds, reason, blockingTime [, action [, warningRate]])
1007 .. versionchanged:: 1.3.3
1008 ``warningRate`` parameter added.
1010 Adds a bandwidth rate-limiting rule for responses, equivalent to:
1012 addDynBlocks(exceedRespByterate(rate, seconds), reason, blockingTime, action)
1015 :param int rate: Number of bytes per second to exceed
1016 :param int seconds: Number of seconds the rate has been exceeded
1017 :param string reason: The message to show next to the blocks
1018 :param int blockingTime: The number of seconds this block to expire
1019 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
1020 :param int warningRate: If set to a non-zero value, the rate above which a warning message will be issued and a no-op block inserted
1022 .. method:: DynBlockRulesGroup:apply()
1024 Walk the in-memory query and response ring buffers and apply the configured rate-limiting rules, adding dynamic blocks when the limits have been exceeded.
1026 .. method:: DynBlockRulesGroup:excludeRange(netmasks)
1028 .. versionadded:: 1.3.1
1030 Exclude this range, or list of ranges, meaning that no dynamic block will ever be inserted for clients in that range. Default to empty, meaning rules are applied to all ranges. When used in combination with :meth:`DynBlockRulesGroup:includeRange`, the more specific entry wins.
1032 :param int netmasks: A netmask, or list of netmasks, as strings, like for example "192.0.2.1/24"
1034 .. method:: DynBlockRulesGroup:includeRange(netmasks)
1036 .. versionadded:: 1.3.1
1038 Include this range, or list of ranges, meaning that rules will be applied to this range. When used in combination with :meth:`DynBlockRulesGroup:excludeRange`, the more specific entry wins.
1040 :param int netmasks: A netmask, or list of netmasks, as strings, like for example "192.0.2.1/24"
1042 .. method:: DynBlockRulesGroup:toString()
1044 .. versionadded:: 1.3.1
1046 Return a string describing the rules and range exclusions of this DynBlockRulesGroup.
1051 .. function:: maintenance()
1053 If this function exists, it is called every second to so regular tasks.
1054 This can be used for e.g. :doc:`Dynamic Blocks <../guides/dynblocks>`.
1056 .. function: setAllowEmptyResponse()
1058 .. versionadded:: 1.4.0
1060 Set to true (defaults to false) to allow empty responses (qdcount=0) with a NoError or NXDomain rcode (default) from backends. dnsdist drops these responses by default because it can't match them against the initial query since they don't contain the qname, qtype and qclass, and therefore the risk of collision is much higher than with regular responses.
1065 .. class:: DOHFrontend
1067 .. versionadded:: 1.4.0
1069 This object represents an address and port dnsdist is listening on for DNS over HTTPS queries.
1071 .. method:: DOHFrontend:reloadCertificates()
1073 Reload the current TLS certificate and key pairs.
1078 .. class:: TLSContext
1080 .. versionadded:: 1.3.0
1082 This object represents an address and port dnsdist is listening on for DNS over TLS queries.
1084 .. method:: TLSContext:rotateTicketsKey()
1086 Replace the current TLS tickets key by a new random one.
1088 .. method:: TLSContext:loadTicketsKeys(ticketsKeysFile)
1090 Load new tickets keys from the selected file, replacing the existing ones. These keys should be rotated often and never written to persistent storage to preserve forward secrecy. The default is to generate a random key. The OpenSSL provider supports several tickets keys to be able to decrypt existing sessions after the rotation, while the GnuTLS provider only supports one key.
1092 :param str ticketsKeysFile: The path to a file from where TLS tickets keys should be loaded.
1097 .. class:: TLSFrontend
1099 .. versionadded:: 1.3.1
1101 This object represents the configuration of a listening frontend for DNS over TLS queries. To each frontend is associated a TLSContext.
1103 .. method:: TLSContext:loadNewCertificatesAndKeys(certFile(s), keyFile(s))
1105 Create and switch to a new TLS context using the same options than were passed to the corresponding `addTLSLocal()` directive, but loading new certificates and keys from the selected files, replacing the existing ones.
1107 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
1108 :param str keyFile(s): The path to the private key file corresponding to the certificate, or a list of paths to such files, whose order should match the certFile(s) ones.
1110 EDNS on Self-generated answers
1111 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1113 There are several mechanisms in dnsdist that turn an existing query into an answer right away,
1114 without reaching out to the backend, including :func:`SpoofAction`, :func:`RCodeAction`, :func:`TCAction`
1115 and returning a response from ``Lua``. Those responses should, according to :rfc:`6891`, contain an ``OPT``
1116 record if the received request had one, which is the case by default and can be disabled using
1117 :func:`setAddEDNSToSelfGeneratedResponses`.
1119 We must, however, provide a responder's maximum payload size in this record, and we can't easily know the
1120 maximum payload size of the actual backend so we need to provide one. The default value is 1500 and can be
1121 overriden using :func:`setPayloadSizeOnSelfGeneratedAnswers`.
1123 .. function:: setAddEDNSToSelfGeneratedResponses(add)
1125 .. versionadded:: 1.3.3
1127 Whether to add EDNS to self-generated responses, provided that the initial query had EDNS.
1129 :param bool add: Whether to add EDNS, default is true.
1131 .. function:: setPayloadSizeOnSelfGeneratedAnswers(payloadSize)
1133 .. versionadded:: 1.3.3
1135 Set the UDP payload size advertised via EDNS on self-generated responses. In accordance with
1136 :rfc:`RFC 6891 <6891#section-6.2.5>`, values lower than 512 will be treated as equal to 512.
1138 :param int payloadSize: The responder's maximum UDP payload size, in bytes. Default is 1500.
1143 PowerDNS products can poll the security status of their respective versions. This polling, naturally,
1144 happens over DNS. If the result is that a given version has a security problem, the software will
1145 report this at level ‘Error’ during startup, and repeatedly during operations, every
1146 :func:`setSecurityPollInterval` seconds.
1148 By default, security polling happens on the domain ‘secpoll.powerdns.com’, but this can be changed with
1149 the :func:`setSecurityPollSuffix` function. If this setting is made empty, no polling will take place.
1150 Organizations wanting to host their own security zones can do so by changing this setting to a domain name
1151 under their control.
1153 To enable distributors of PowerDNS to signal that they have backported versions, the PACKAGEVERSION
1154 compilation-time macro can be used to set a distributor suffix.
1156 .. function:: setSecurityPollInterval(interval)
1158 .. versionadded:: 1.3.3
1160 Set the interval, in seconds, between two security pollings.
1162 :param int interval: The interval, in seconds, between two pollings. Default is 3600.
1164 .. function:: setSecurityPollSuffix(suffix)
1166 .. versionadded:: 1.3.3
1168 Domain name from which to query security update notifications. Setting this to an empty string disables secpoll.
1170 :param string suffix: The suffix to use, default is 'secpoll.powerdns.com.'.