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.
54 .. function:: addLocal(address[, options])
56 .. versionadded:: 1.2.0
58 .. versionchanged:: 1.3.0
59 Added ``cpus`` to the options.
61 Add to the list of listen addresses.
63 :param str address: The IP Address with an optional port to listen on.
64 The default port is 53.
65 :param table options: A table with key: value pairs with listen options.
69 * ``doTCP=true``: bool - Also bind on TCP on ``address``.
70 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
71 * ``tcpFastOpenSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
72 * ``interface=""``: str - Set the network interface to use.
73 * ``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.
77 addLocal('0.0.0.0:5300', { doTCP=true, reusePort=true })
79 This will bind to both UDP and TCP on port 5300 with SO_REUSEPORT enabled.
81 .. function:: addLocal(address[[[,do_tcp], so_reuseport], tcp_fast_open_qsize])
85 Add to the list of addresses listened on.
87 :param str address: The IP Address with an optional port to listen on.
88 The default port is 53.
89 :param bool do_tcp: Also bind a TCP port on ``address``, defaults to true.
90 :param bool so_reuseport: Use ``SO_REUSEPORT`` if it is available, defaults to false
91 :param int tcp_fast_open_qsize: The size of the TCP Fast Open queue. Set to a number
92 higher than 0 to enable TCP Fast Open when available.
95 .. function:: addTLSLocal(address, certFile(s), keyFile(s) [, options])
97 .. versionadded:: 1.3.0
98 .. versionchanged:: 1.3.1
99 ``certFile(s)`` and ``keyFile(s)`` parameters accept a list of files.
100 ``sessionTickets`` option added.
101 .. versionchanged:: 1.3.3
102 ``numberOfStoredSessions`` option added.
104 Listen on the specified address and TCP port for incoming DNS over TLS connections, presenting the specified X.509 certificate.
106 :param str address: The IP Address with an optional port to listen on.
107 The default port is 853.
108 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
109 :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.
110 :param table options: A table with key: value pairs with listen options.
114 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
115 * ``tcpFastOpenSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
116 * ``interface=""``: str - Set the network interface to use.
117 * ``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.
118 * ``provider``: str - The TLS library to use between GnuTLS and OpenSSL, if they were available and enabled at compilation time.
119 * ``ciphers``: str - The TLS ciphers to use. The exact format depends on the provider used.
120 * ``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.
121 * ``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.
122 * ``ticketsKeysRotationDelay``: int - Set the delay before the TLS tickets key is rotated, in seconds. Default is 43200 (12h).
123 * ``sessionTickets``: bool - Whether session resumption via session tickets is enabled. Default is true, meaning tickets are enabled.
124 * ``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.
126 .. function:: setLocal(address[, options])
128 .. versionadded:: 1.2.0
130 Remove the list of listen addresses and add a new one.
132 :param str address: The IP Address with an optional port to listen on.
133 The default port is 53.
134 :param table options: A table with key: value pairs with listen options.
136 The options that can be set are the same as :func:`addLocal`.
138 .. function:: setLocal(address[[[,do_tcp], so_reuseport], tcp_fast_open_qsize])
140 .. deprecated:: 1.2.0
142 Remove the list of listen addresses and add a new one.
144 :param str address: The IP Address with an optional port to listen on.
145 The default port is 53.
146 :param bool do_tcp: Also bind a TCP port on ``address``, defaults to true.
147 :param bool so_reuseport: Use ``SO_REUSEPORT`` if it is available, defaults to false
148 :param int tcp_fast_open_qsize: The size of the TCP Fast Open queue. Set to a number
149 higher than 0 to enable TCP Fast Open when available.
152 Control Socket, Console and Webserver
153 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
155 .. function:: addConsoleACL(netmask)
157 .. versionadded:: 1.3.0
159 Add a netmask to the existing console ACL, allowing remote clients to connect to the console. Please make sure that encryption
160 has been enabled with :func:`setKey` before doing so. The default is to only allow 127.0.0.1/8 and ::1/128.
162 :param str netmask: A CIDR netmask, e.g. ``"192.0.2.0/24"``. Without a subnetmask, only the specific address is allowed.
164 .. function:: controlSocket(address)
166 Bind to ``addr`` and listen for a connection for the console. Since 1.3.0 only connections from local users are allowed
167 by default, :func:`addConsoleACL` and :func:`setConsoleACL` can be used to enable remote connections. Please make sure
168 that encryption has been enabled with :func:`setKey` before doing so. Enabling encryption is also strongly advised for
169 local connections, since not enabling it allows any local user to connect to the console.
171 :param str address: An IP address with optional port. By default, the port is 5199.
173 .. function:: inClientStartup()
175 Returns true while the console client is parsing the configuration.
177 .. function:: makeKey()
179 Generate and print an encryption key.
181 .. function:: setConsoleConnectionsLogging(enabled)
183 .. versionadded:: 1.2.0
185 Whether to log the opening and closing of console connections.
187 :param bool enabled: Default to true.
189 .. function:: setKey(key)
191 Use ``key`` as shared secret between the client and the server
193 :param str key: An encoded key, as generated by :func:`makeKey`
195 .. function:: setConsoleACL(netmasks)
197 .. versionadded:: 1.3.0
199 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
200 has been enabled with :func:`setKey` before doing so.
202 :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.
204 .. function:: showConsoleACL()
206 Print a list of all netmasks allowed to connect to the console.
208 .. function:: testCrypto()
210 Test the crypto code, will report errors when something is not ok.
212 .. function:: setConsoleOutputMaxMsgSize(size)
214 .. versionadded:: 1.3.3
216 Set the maximum size in bytes of a single console message, default set to 10 MB.
218 :param int size: The new maximum size.
220 Webserver configuration
221 ~~~~~~~~~~~~~~~~~~~~~~~
223 .. function:: webserver(listen_address, password[, apikey[, custom_headers]])
225 Launch the :doc:`../guides/webserver` with statistics and the API.
227 :param str listen_address: The IP address and Port to listen on
228 :param str password: The password required to access the webserver
229 :param str apikey: The key required to access the API
230 :param {[str]=str,...} custom_headers: Allows setting custom headers and removing the defaults
232 .. function:: setAPIWritable(allow [,dir])
234 Allow modifications via the API.
235 Optionally saving these changes to disk.
236 Modifications done via the API will not be written to the configuration by default and will not persist after a reload
238 :param bool allow: Set to true to allow modification through the API
239 :param str dir: A valid directory where the configuration files will be written by the API.
241 .. function:: setWebserverConfig(options)
243 .. versionadded:: 1.3.3
245 Setup webserver configuration. See :func:`webserver`.
247 :param table options: A table with key: value pairs with webserver options.
251 * ``password=newPassword``: string - Changes the API password
252 * ``apikey=newKey``: string - Changes the API Key (set to an empty string do disable it)
253 * ``custom_headers={[str]=str,...}``: map of string - Allows setting custom headers and removing the defaults.
258 .. function:: addACL(netmask)
260 Add a netmask to the existing ACL controlling which clients can send UDP and TCP queries. See :ref:`ACL` for more information.
262 :param str netmask: A CIDR netmask, e.g. ``"192.0.2.0/24"``. Without a subnetmask, only the specific address is allowed.
264 .. function:: setACL(netmasks)
266 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.
268 :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.
270 .. function:: showACL()
272 Print a list of all netmasks allowed to send queries over UDP and TCP. See :ref:`ACL` for more information.
277 .. function:: setECSSourcePrefixV4(prefix)
279 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
281 :param int prefix: The prefix length
283 .. function:: setECSSourcePrefixV6(prefix)
285 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
287 :param int prefix: The prefix length
292 .. function:: setRingBuffersLockRetries(num)
294 .. versionadded:: 1.3.0
296 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
298 :param int num: The maximum number of attempts. Defaults to 5 if there is more than one shard, 0 otherwise.
300 .. function:: setRingBuffersSize(num [, numberOfShards])
302 .. versionchanged:: 1.3.0
303 ``numberOfShards`` optional parameter added.
305 Set the capacity of the ringbuffers used for live traffic inspection to ``num``, and the number of shards to ``numberOfShards`` if specified.
307 :param int num: The maximum amount of queries to keep in the ringbuffer. Defaults to 10000
308 :param int numberOfShards: the number of shards to use to limit lock contention. Defaults to 1
313 .. function:: newServer(server_string)
314 newServer(server_table)
316 .. versionchanged:: 1.3.0
317 Added ``checkClass``, ``sockets`` and ``checkFunction`` to server_table.
319 .. versionchanged:: 1.3.4
320 Added ``checkTimeout`` and ``rise`` to server_table.
322 Add a new backend server. Call this function with either a string::
325 "IP:PORT" -- IP and PORT of the backend server
331 address="IP:PORT", -- IP and PORT of the backend server (mandatory)
332 id=STRING, -- Use a pre-defined UUID instead of a random one
333 qps=NUM, -- Limit the number of queries per second to NUM, when using the `firstAvailable` policy
334 order=NUM, -- The order of this server, used by the `leastOustanding` and `firstAvailable` policies
335 weight=NUM, -- The weight of this server, used by the `wrandom`, `whashed` and `chashed` policies, default: 1
336 -- Supported values are a minimum of 1, and a maximum of 2147483647.
337 pool=STRING|{STRING}, -- The pools this server belongs to (unset or empty string means default pool) as a string or table of strings
338 retries=NUM, -- The number of TCP connection attempts to the backend, for a given query
339 tcpConnectTimeout=NUM, -- The timeout (in seconds) of a TCP connection attempt
340 tcpSendTimeout=NUM, -- The timeout (in seconds) of a TCP write attempt
341 tcpRecvTimeout=NUM, -- The timeout (in seconds) of a TCP read attempt
342 tcpFastOpen=BOOL, -- Whether to enable TCP Fast Open
343 ipBindAddrNoPort=BOOL, -- Whether to enable IP_BIND_ADDRESS_NO_PORT if available, default: true
344 name=STRING, -- The name associated to this backend, for display purpose
345 checkClass=NUM, -- Use NUM as QCLASS in the health-check query, default: DNSClass.IN
346 checkName=STRING, -- Use STRING as QNAME in the health-check query, default: "a.root-servers.net."
347 checkType=STRING, -- Use STRING as QTYPE in the health-check query, default: "A"
348 checkFunction=FUNCTION,-- Use this function to dynamically set the QNAME, QTYPE and QCLASS to use in the health-check query (see :ref:`Healthcheck`)
349 checkTimeout=NUM, -- The timeout (in milliseconds) of a health-check query, default: 1000 (1s)
350 setCD=BOOL, -- Set the CD (Checking Disabled) flag in the health-check query, default: false
351 maxCheckFailures=NUM, -- Allow NUM check failures before declaring the backend down, default: 1
352 checkInterval=NUM -- The time in seconds between health checks
353 mustResolve=BOOL, -- Set to true when the health check MUST return a NOERROR RCODE and an answer
354 useClientSubnet=BOOL, -- Add the client's IP address in the EDNS Client Subnet option when forwarding the query to this backend
355 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
356 -- The following formats are supported:
357 -- "address", e.g. "192.0.2.2"
358 -- "interface name", e.g. "eth0"
359 -- "address@interface", e.g. "192.0.2.2@eth0"
360 addXPF=NUM, -- Add the client's IP address and port to the query, along with the original destination address and port,
361 -- 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)
362 sockets=NUM, -- Number of sockets (and thus source ports) used toward the backend server, defaults to a single one
363 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
364 rise=NUM -- Require NUM consecutive successful checks before declaring the backend up, default: 1
367 :param str server_string: A simple IP:PORT string.
368 :param table server_table: A table with at least a 'name' key
370 .. function:: getServer(index) -> Server
372 Get a :class:`Server`
374 :param int index: The number of the server (as seen in :func:`showServers`).
375 :returns: The :class:`Server` object or nil
377 .. function:: getServers()
379 Returns a table with all defined servers.
381 .. function:: rmServer(index)
384 Remove a backend server.
386 :param int index: The number of the server (as seen in :func:`showServers`).
387 :param Server server: A :class:`Server` object as returned by e.g. :func:`getServer`.
391 A server object returned by :func:`getServer` can be manipulated with these functions.
395 This object represents a backend server. It has several methods.
397 .. method:: Server:addPool(pool)
399 Add this server to a pool.
401 :param str pool: The pool to add the server to
403 .. method:: Server:getName() -> string
405 Get the name of this server.
407 :returns: The name of the server, or an empty string if it does not have one
409 .. method:: Server:getNameWithAddr() -> string
411 Get the name plus IP address and port of the server
413 :returns: A string containing the server name if any plus the server address and port
415 .. method:: Server:getOutstanding() -> int
417 Get the number of outstanding queries for this server.
419 :returns: The number of outstanding queries
421 .. method:: Server:isUp() -> bool
423 Returns the up status of the server
425 :returns: true when the server is up, false otherwise
427 .. method:: Server:rmPool(pool)
429 Removes the server from the named pool
431 :param str pool: The pool to remove the server from
433 .. method:: Server:setAuto([status])
435 .. versionchanged:: 1.3.0
436 ``status`` optional parameter added.
438 Set the server in the default auto state.
439 This will enable health check queries that will set the server ``up`` and ``down`` appropriately.
441 :param bool status: Set the initial status of the server to ``up`` (true) or ``down`` (false) instead of using the last known status
443 .. method:: Server:setQPS(limit)
445 Limit the queries per second for this server.
447 :param int limit: The maximum number of queries per second
449 .. method:: Server:setDown()
451 Set the server in an ``DOWN`` state.
452 The server will not receive queries and the health checks are disabled
454 .. method:: Server:setUp()
456 Set the server in an ``UP`` state.
457 This server will still receive queries and health checks are disabled
459 Apart from the functions, a :class:`Server` object has these attributes:
461 .. attribute:: Server.name
463 The name of the server
465 .. attribute:: Server.upStatus
467 Whether or not this server is up or down
469 .. attribute:: Server.order
471 The order of the server
473 .. attribute:: Server.weight
475 The weight of the server
480 :class:`Server`\ s can be part of any number of pools.
481 Pools are automatically created when a server is added to a pool (with :func:`newServer`), or can be manually created with :func:`addPool`.
483 .. function:: addPool(name) -> ServerPool
485 Returns a :class:`ServerPool`.
487 :param string name: The name of the pool to create
489 .. function:: getPool(name) -> ServerPool
491 Returns a :class:`ServerPool` or nil.
493 :param string name: The name of the pool
495 .. function:: getPoolServers(name) -> [ Server ]
497 Returns a list of :class:`Server`\ s or nil.
499 :param string name: The name of the pool
501 .. function:: showPools()
503 Display the name, associated cache, server policy and associated servers for every pool.
505 .. class:: ServerPool
507 This represents the pool where zero or more servers are part of.
509 .. method:: ServerPool:getCache() -> PacketCache
511 Returns the :class:`PacketCache` for this pool or nil.
513 .. method:: ServerPool:getECS()
515 .. versionadded:: 1.3.0
517 Whether dnsdist will add EDNS Client Subnet information to the query before looking up into the cache,
518 when all servers from this pool are down. For more information see :meth:`ServerPool:setECS`.
520 .. method:: ServerPool:setCache(cache)
522 Adds ``cache`` as the pool's cache.
524 :param PacketCache cache: The new cache to add to the pool
526 .. method:: ServerPool:unsetCache()
528 Removes the cache from this pool.
530 .. method:: ServerPool:setECS()
532 .. versionadded:: 1.3.0
534 Set to true if dnsdist should add EDNS Client Subnet information to the query before looking up into the cache,
535 when all servers from this pool are down. If at least one server is up, the preference of the
536 selected server is used, this parameter is only useful if all the backends in this pool are down
537 and have EDNS Client Subnet enabled, since the queries in the cache will have been inserted with
538 ECS information. Default is false.
543 A Pool can have a packet cache to answer queries directly in stead of going to the backend.
544 See :doc:`../guides/cache` for a how to.
546 .. function:: newPacketCache(maxEntries[, maxTTL=86400[, minTTL=0[, temporaryFailureTTL=60[, staleTTL=60[, dontAge=false[, numberOfShards=1[, deferrableInsertLock=true[, maxNegativeTTL=3600[, parseECS=false [,options]]]]]]]]) -> PacketCache
548 .. versionchanged:: 1.3.0
549 ``numberOfShards`` and ``deferrableInsertLock`` parameters added.
551 .. versionchanged:: 1.3.1
552 ``maxNegativeTTL`` and ``parseECS`` parameters added.
554 .. versionchanged:: 1.3.4
555 ``options`` parameter added.
557 Creates a new :class:`PacketCache` with the settings specified.
558 Starting with 1.3.4, all parameters can be specified in the ``options`` table, overriding the value from the existing parameters if any.
560 :param int maxEntries: The maximum number of entries in this cache
561 :param int maxTTL: Cap the TTL for records to his number
562 :param int minTTL: Don't cache entries with a TTL lower than this
563 :param int temporaryFailureTTL: On a SERVFAIL or REFUSED from the backend, cache for this amount of seconds
564 :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
565 :param bool dontAge: Don't reduce TTLs when serving from the cache. Use this when :program:`dnsdist` fronts a cluster of authoritative servers
566 :param int numberOfShards: Number of shards to divide the cache into, to reduce lock contention
567 :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
568 :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
569 :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
570 :param table options: A table with key: value pairs with the options listed below:
574 * ``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.
575 * ``dontAge=false``: bool - Don't reduce TTLs when serving from the cache. Use this when :program:`dnsdist` fronts a cluster of authoritative servers.
576 * ``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.
577 * ``maxEntries``: int - The maximum number of entries in this cache.
578 * ``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.
579 * ``maxTTL=86400``: int - Cap the TTL for records to his number.
580 * ``minTTL=0``: int - Don't cache entries with a TTL lower than this.
581 * ``numberOfShards=1``: int - Number of shards to divide the cache into, to reduce lock contention.
582 * ``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.
583 * ``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.
584 * ``temporaryFailureTTL=60``: int - On a SERVFAIL or REFUSED from the backend, cache for this amount of seconds..
586 .. class:: PacketCache
588 Represents a cache that can be part of :class:`ServerPool`.
590 .. method:: PacketCache:dump(fname)
592 .. versionadded:: 1.3.1
594 Dump a summary of the cache entries to a file.
596 :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.
598 .. method:: PacketCache:expunge(n)
600 Remove entries from the cache, leaving at most ``n`` entries
602 :param int n: Number of entries to keep
604 .. method:: PacketCache:expungeByName(name [, qtype=dnsdist.ANY[, suffixMatch=false]])
606 .. versionchanged:: 1.2.0
607 ``suffixMatch`` parameter added.
609 Remove entries matching ``name`` and type from the cache.
611 :param DNSName name: The name to expunge
612 :param int qtype: The type to expunge
613 :param bool suffixMatch: When set to true, remove al entries under ``name``
615 .. method:: PacketCache:getStats()
617 .. versionadded:: 1.3.4
619 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.
621 .. method:: PacketCache:isFull() -> bool
623 Return true if the cache has reached the maximum number of entries.
625 .. method:: PacketCache:printStats()
627 Print the cache stats (number of entries, hits, misses, deferred lookups, deferred inserts, lookup collisions, insert collisions and TTL too shorts).
629 .. method:: PacketCache:purgeExpired(n)
631 Remove expired entries from the cache until there is at most ``n`` entries remaining in the cache.
633 :param int n: Number of entries to keep
635 .. method:: PacketCache:toString() -> string
637 Return the number of entries in the Packet Cache, and the maximum number of entries
642 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.
644 .. function:: getBind(index) -> ClientState
646 Return a :class:`ClientState` object.
648 :param int index: The object index
650 ClientState functions
651 ~~~~~~~~~~~~~~~~~~~~~
653 .. class:: ClientState
655 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.
657 .. method:: ClientState:attachFilter(filter)
659 Attach a BPF filter to this frontend.
661 :param BPFFilter filter: The filter to attach to this frontend
663 .. method:: ClientState:detachFilter()
665 Remove the BPF filter associated to this frontend, if any.
667 .. method:: ClientState:toString() -> string
669 Return the address and port this frontend is listening on.
671 :returns: The address and port this frontend is listening on
673 .. attribute:: ClientState.muted
675 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.
677 Status, Statistics and More
678 ---------------------------
680 .. function:: dumpStats()
682 Print all statistics dnsdist gathers
684 .. function:: getTLSContext(idx)
686 .. versionadded:: 1.3.0
688 Return the TLSContext object for the context of index ``idx``.
690 .. function:: getTLSFrontend(idx)
692 .. versionadded:: 1.3.1
694 Return the TLSFrontend object for the TLS bind of index ``idx``.
696 .. function:: grepq(selector[, num])
697 grepq(selectors[, num])
699 Prints the last ``num`` queries matching ``selector`` or ``selectors``.
703 * a netmask (e.g. '192.0.2.0/24')
704 * a DNS name (e.g. 'dnsdist.org')
705 * a response time (e.g. '100ms')
707 :param str selector: Select queries based on this property.
708 :param {str} selectors: A lua table of selectors. Only queries matching all selectors are shown
709 :param int num: Show a maximum of ``num`` recent queries, default is 10.
711 .. function:: setVerboseHealthChecks(verbose)
713 Set whether health check errors should be logged. This is turned off by default.
715 :param bool verbose: Set to true if you want to enable health check errors logging
717 .. function:: showBinds()
719 Print a list of all the current addresses and ports dnsdist is listening on, also called ``frontends``
721 .. function:: showResponseLatency()
723 Show a plot of the response time latency distribution
725 .. function:: showServers([options])
727 .. versionchanged:: 1.3.4
728 ``options`` optional parameter added
730 This function shows all backend servers currently configured and some statistics.
731 These statics have the following fields:
733 * ``#`` - The number of the server, can be used as the argument for :func:`getServer`
734 * ``UUID`` - The UUID of the backend. Can be set with the ``id`` option of :func:`newServer`
735 * ``Address`` - The IP address and port of the server
736 * ``State`` - The current state of the server
737 * ``Qps`` - Current number of queries per second
738 * ``Qlim`` - Configured maximum number of queries per second
739 * ``Ord`` - The order number of the server
740 * ``Wt`` - The weight of the server
741 * ``Queries`` - Total amount of queries sent to this server
742 * ``Drops`` - Number of queries that were dropped by this server
743 * ``Drate`` - Number of queries dropped per second by this server
744 * ``Lat`` - The latency of this server in milliseconds
745 * ``Pools`` - The pools this server belongs to
747 :param table options: A table with key: value pairs with display options.
751 * ``showUUIDs=false``: bool - Whether to display the UUIDs, defaults to false.
753 .. function:: showTCPStats()
755 Show some statistics regarding TCP
757 .. function:: showTLSContexts()
759 .. versionadded:: 1.3.0
761 Print the list of all availables DNS over TLS contexts.
763 .. function:: showVersion()
765 Print the version of dnsdist
767 .. function:: topBandwidth([num])
769 Print the top ``num`` clients that consume the most bandwidth.
771 :param int num: Number to show, defaults to 10.
773 .. function:: topClients([num])
775 Print the top ``num`` clients sending the most queries over length of ringbuffer
777 :param int num: Number to show, defaults to 10.
779 .. function:: topQueries([num[, labels]])
781 Print the ``num`` most popular QNAMEs from queries.
782 Optionally grouped by the rightmost ``labels`` DNS labels.
784 :param int num: Number to show, defaults to 10
785 :param int label: Number of labels to cut down to
787 .. function:: topResponses([num[, rcode[, labels]]])
789 Print the ``num`` most seen responses with an RCODE of ``rcode``.
790 Optionally grouped by the rightmost ``labels`` DNS labels.
792 :param int num: Number to show, defaults to 10
793 :param int rcode: :ref:`Response code <DNSRCode>`, defaults to 0 (No Error)
794 :param int label: Number of labels to cut down to
796 .. function:: topSlow([num[, limit[, labels]]])
798 Print the ``num`` slowest queries that are slower than ``limit`` milliseconds.
799 Optionally grouped by the rightmost ``labels`` DNS labels.
801 :param int num: Number to show, defaults to 10
802 :param int limit: Show queries slower than this amount of milliseconds, defaults to 2000
803 :param int label: Number of labels to cut down to
810 .. function:: addDynBlocks(addresses, message[, seconds=10[, action]])
812 .. versionchanged:: 1.2.0
813 ``action`` parameter added.
815 Block a set of addresses with ``message`` for (optionally) a number of seconds.
816 The default number of seconds to block for is 10.
818 :param addresses: set of Addresses as returned by an exceed function
819 :param string message: The message to show next to the blocks
820 :param int seconds: The number of seconds this block to expire
821 :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)
823 Please see the documentation for :func:`setDynBlocksAction` to confirm which actions are supported by the action paramater.
825 .. function:: clearDynBlocks()
827 Remove all current dynamic blocks.
829 .. function:: showDynBlocks()
831 List all dynamic blocks in effect.
833 .. function:: setDynBlocksAction(action)
835 .. versionchanged:: 1.3.3
836 ``DNSAction.NXDomain`` action added.
838 Set which action is performed when a query is blocked.
839 Only DNSAction.Drop (the default), DNSAction.NoOp, DNSAction.NXDomain, DNSAction.Refused, DNSAction.Truncate and DNSAction.NoRecurse are supported.
843 Getting addresses that exceeded parameters
844 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
846 .. function:: exceedServFails(rate, seconds)
848 Get set of addresses that exceed ``rate`` servfails/s over ``seconds`` seconds
850 :param int rate: Number of Servfails per second to exceed
851 :param int seconds: Number of seconds the rate has been exceeded
853 .. function:: exceedNXDOMAINs(rate, seconds)
855 get set of addresses that exceed ``rate`` NXDOMAIN/s over ``seconds`` seconds
857 :param int rate: Number of NXDOMAIN per second to exceed
858 :param int seconds: Number of seconds the rate has been exceeded
860 .. function:: exceedRespByterate(rate, seconds)
862 get set of addresses that exceeded ``rate`` bytes/s answers over ``seconds`` seconds
864 :param int rate: Number of bytes per second to exceed
865 :param int seconds: Number of seconds the rate has been exceeded
867 .. function:: exceedQRate(rate, seconds)
869 Get set of address that exceed ``rate`` queries/s over ``seconds`` seconds
871 :param int rate: Number of queries per second to exceed
872 :param int seconds: Number of seconds the rate has been exceeded
874 .. function:: exceedQTypeRate(type, rate, seconds)
876 Get set of address that exceed ``rate`` queries/s for queries of QType ``type`` over ``seconds`` seconds
878 :param int type: QType
879 :param int rate: Number of QType queries per second to exceed
880 :param int seconds: Number of seconds the rate has been exceeded
885 Instead of using several `exceed*()` lines, dnsdist 1.3.0 introduced a new `DynBlockRulesGroup` object
886 which can be used to group dynamic block rules.
888 See :doc:`../guides/dynblocks` for more information about the case where using a `DynBlockRulesGroup` might be
889 faster than the existing rules.
891 .. function:: dynBlockRulesGroup() -> DynBlockRulesGroup
893 .. versionadded:: 1.3.0
895 Creates a new :class:`DynBlockRulesGroup` object.
897 .. class:: DynBlockRulesGroup
899 Represents a group of dynamic block rules.
901 .. method:: DynBlockRulesGroup:setQueryRate(rate, seconds, reason, blockingTime [, action [, warningRate]])
903 .. versionchanged:: 1.3.3
904 ``warningRate`` parameter added.
906 Adds a query rate-limiting rule, equivalent to:
908 addDynBlocks(exceedQRate(rate, seconds), reason, blockingTime, action)
911 :param int rate: Number of queries per second to exceed
912 :param int seconds: Number of seconds the rate has been exceeded
913 :param string reason: The message to show next to the blocks
914 :param int blockingTime: The number of seconds this block to expire
915 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
916 :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
918 .. method:: DynBlockRulesGroup:setRCodeRate(rcode, rate, seconds, reason, blockingTime [, action [, warningRate]])
920 .. versionchanged:: 1.3.3
921 ``warningRate`` parameter added.
923 Adds a rate-limiting rule for responses of code ``rcode``, equivalent to:
925 addDynBlocks(exceedServfails(rcode, rate, seconds), reason, blockingTime, action)
928 :param int rcode: The response code
929 :param int rate: Number of responses per second to exceed
930 :param int seconds: Number of seconds the rate has been exceeded
931 :param string reason: The message to show next to the blocks
932 :param int blockingTime: The number of seconds this block to expire
933 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
934 :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
936 .. method:: DynBlockRulesGroup:setQTypeRate(qtype, rate, seconds, reason, blockingTime [, action [, warningRate]])
938 .. versionchanged:: 1.3.3
939 ``warningRate`` parameter added.
941 Adds a rate-limiting rule for queries of type ``qtype``, equivalent to:
943 addDynBlocks(exceedQTypeRate(type, rate, seconds), reason, blockingTime, action)
946 :param int qtype: The qtype
947 :param int rate: Number of queries per second to exceed
948 :param int seconds: Number of seconds the rate has been exceeded
949 :param string reason: The message to show next to the blocks
950 :param int blockingTime: The number of seconds this block to expire
951 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
952 :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
954 .. method:: DynBlockRulesGroup:setResponseByteRate(rate, seconds, reason, blockingTime [, action [, warningRate]])
956 .. versionchanged:: 1.3.3
957 ``warningRate`` parameter added.
959 Adds a bandwidth rate-limiting rule for responses, equivalent to:
961 addDynBlocks(exceedRespByterate(rate, seconds), reason, blockingTime, action)
964 :param int rate: Number of bytes per second to exceed
965 :param int seconds: Number of seconds the rate has been exceeded
966 :param string reason: The message to show next to the blocks
967 :param int blockingTime: The number of seconds this block to expire
968 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
969 :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
971 .. method:: DynBlockRulesGroup:apply()
973 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.
975 .. method:: DynBlockRulesGroup:excludeRange(netmasks)
977 .. versionadded:: 1.3.1
979 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.
981 :param int netmasks: A netmask, or list of netmasks, as strings, like for example "192.0.2.1/24"
983 .. method:: DynBlockRulesGroup:includeRange(netmasks)
985 .. versionadded:: 1.3.1
987 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.
989 :param int netmasks: A netmask, or list of netmasks, as strings, like for example "192.0.2.1/24"
991 .. method:: DynBlockRulesGroup:toString()
993 .. versionadded:: 1.3.1
995 Return a string describing the rules and range exclusions of this DynBlockRulesGroup.
1000 .. function:: maintenance()
1002 If this function exists, it is called every second to so regular tasks.
1003 This can be used for e.g. :doc:`Dynamic Blocks <../guides/dynblocks>`.
1005 .. function: setAllowEmptyResponse()
1007 .. versionadded:: 1.4.0
1009 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.
1014 .. class:: TLSContext
1016 .. versionadded:: 1.3.0
1018 This object represents an address and port dnsdist is listening on for DNS over TLS queries.
1020 .. method:: TLSContext:rotateTicketsKey()
1022 Replace the current TLS tickets key by a new random one.
1024 .. method:: TLSContext:loadTicketsKeys(ticketsKeysFile)
1026 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.
1028 :param str ticketsKeysFile: The path to a file from where TLS tickets keys should be loaded.
1033 .. class:: TLSFrontend
1035 .. versionadded:: 1.3.1
1037 This object represents the configuration of a listening frontend for DNS over TLS queries. To each frontend is associated a TLSContext.
1039 .. method:: TLSContext:loadNewCertificatesAndKeys(certFile(s), keyFile(s))
1041 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.
1043 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
1044 :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.
1046 EDNS on Self-generated answers
1047 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1049 There are several mechanisms in dnsdist that turn an existing query into an answer right away,
1050 without reaching out to the backend, including :func:`SpoofAction`, :func:`RCodeAction`, :func:`TCAction`
1051 and returning a response from ``Lua``. Those responses should, according to :rfc:`6891`, contain an ``OPT``
1052 record if the received request had one, which is the case by default and can be disabled using
1053 :func:`setAddEDNSToSelfGeneratedResponses`.
1055 We must, however, provide a responder's maximum payload size in this record, and we can't easily know the
1056 maximum payload size of the actual backend so we need to provide one. The default value is 1500 and can be
1057 overriden using :func:`setPayloadSizeOnSelfGeneratedAnswers`.
1059 .. function:: setAddEDNSToSelfGeneratedResponses(add)
1061 .. versionadded:: 1.3.3
1063 Whether to add EDNS to self-generated responses, provided that the initial query had EDNS.
1065 :param bool add: Whether to add EDNS, default is true.
1067 .. function:: setPayloadSizeOnSelfGeneratedAnswers(payloadSize)
1069 .. versionadded:: 1.3.3
1071 Set the UDP payload size advertised via EDNS on self-generated responses. In accordance with
1072 :rfc:`RFC 6891 <6891#section-6.2.5>`, values lower than 512 will be treated as equal to 512.
1074 :param int payloadSize: The responder's maximum UDP payload size, in bytes. Default is 1500.
1079 PowerDNS products can poll the security status of their respective versions. This polling, naturally,
1080 happens over DNS. If the result is that a given version has a security problem, the software will
1081 report this at level ‘Error’ during startup, and repeatedly during operations, every
1082 :func:`setSecurityPollInterval` seconds.
1084 By default, security polling happens on the domain ‘secpoll.powerdns.com’, but this can be changed with
1085 the :func:`setSecurityPollSuffix` function. If this setting is made empty, no polling will take place.
1086 Organizations wanting to host their own security zones can do so by changing this setting to a domain name
1087 under their control.
1089 To enable distributors of PowerDNS to signal that they have backported versions, the PACKAGEVERSION
1090 compilation-time macro can be used to set a distributor suffix.
1092 .. function:: setSecurityPollInterval(interval)
1094 .. versionadded:: 1.3.3
1096 Set the interval, in seconds, between two security pollings.
1098 :param int interval: The interval, in seconds, between two pollings. Default is 3600.
1100 .. function:: setSecurityPollSuffix(suffix)
1102 .. versionadded:: 1.3.3
1104 Domain name from which to query security update notifications. Setting this to an empty string disables secpoll.
1106 :param string suffix: The suffix to use, default is 'secpoll.powerdns.com.'.