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 .. versionchanged:: 1.4.0
70 Removed ``doTCP`` from the options. A listen socket on TCP is always created.
72 Add to the list of listen addresses.
74 :param str address: The IP Address with an optional port to listen on.
75 The default port is 53.
76 :param table options: A table with key: value pairs with listen options.
80 * ``doTCP=true``: bool - Also bind on TCP on ``address``. Removed in 1.4.0.
81 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
82 * ``tcpFastOpenQueueSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
83 * ``interface=""``: str - Set the network interface to use.
84 * ``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.
88 addLocal('0.0.0.0:5300', { reusePort=true })
90 This will bind to both UDP and TCP on port 5300 with SO_REUSEPORT enabled.
92 .. function:: addLocal(address[[[,do_tcp], so_reuseport], tcp_fast_open_qsize])
96 Add to the list of addresses listened on.
98 :param str address: The IP Address with an optional port to listen on.
99 The default port is 53.
100 :param bool do_tcp: Also bind a TCP port on ``address``, defaults to true.
101 :param bool so_reuseport: Use ``SO_REUSEPORT`` if it is available, defaults to false
102 :param int tcp_fast_open_qsize: The size of the TCP Fast Open queue. Set to a number
103 higher than 0 to enable TCP Fast Open when available.
106 .. function:: addDOHLocal(address, certFile(s), keyFile(s) [, urls [, options]])
108 .. versionadded:: 1.4.0
110 Listen on the specified address and TCP port for incoming DNS over HTTPS connections, presenting the specified X.509 certificate.
112 :param str address: The IP Address with an optional port to listen on.
113 The default port is 443.
114 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
115 :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.
116 :param str-or-list urls: A base URL, or a list of base URLs, to accept queries on. Any query with a path under one of these will be treated as a DoH query. The default is /.
117 :param table options: A table with key: value pairs with listen options.
121 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
122 * ``tcpFastOpenQueueSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
123 * ``interface=""``: str - Set the network interface to use.
124 * ``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.
125 * ``idleTimeout=30``: int - Set the idle timeout, in seconds.
126 * ``ciphers``: str - The TLS ciphers to use, in OpenSSL format. Ciphers for TLS 1.3 must be specified via ``ciphersTLS13``.
127 * ``ciphersTLS13``: str - The TLS ciphers to use for TLS 1.3, in OpenSSL format.
128 * ``serverTokens``: str - The content of the Server: HTTP header returned by dnsdist. The default is "h2o/dnsdist".
129 * ``customResponseHeaders={}``: table - Set custom HTTP header(s) returned by dnsdist.
130 * ``ocspResponses``: list - List of files containing OCSP responses, in the same order than the certificates and keys, that will be used to provide OCSP stapling responses.
132 .. function:: addTLSLocal(address, certFile(s), keyFile(s) [, options])
134 .. versionadded:: 1.3.0
135 .. versionchanged:: 1.3.1
136 ``certFile(s)`` and ``keyFile(s)`` parameters accept a list of files.
137 ``sessionTickets`` option added.
138 .. versionchanged:: 1.3.3
139 ``numberOfStoredSessions`` option added.
140 .. versionchanged:: 1.4.0
141 ``ciphersTLS13`` and ``ocspResponses`` options added.
143 Listen on the specified address and TCP port for incoming DNS over TLS connections, presenting the specified X.509 certificate.
145 :param str address: The IP Address with an optional port to listen on.
146 The default port is 853.
147 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
148 :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.
149 :param table options: A table with key: value pairs with listen options.
153 * ``reusePort=false``: bool - Set the ``SO_REUSEPORT`` socket option.
154 * ``tcpFastOpenQueueSize=0``: int - Set the TCP Fast Open queue size, enabling TCP Fast Open when available and the value is larger than 0.
155 * ``interface=""``: str - Set the network interface to use.
156 * ``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.
157 * ``provider``: str - The TLS library to use between GnuTLS and OpenSSL, if they were available and enabled at compilation time.
158 * ``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``.
159 * ``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.
160 * ``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.
161 * ``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.
162 * ``ticketsKeysRotationDelay``: int - Set the delay before the TLS tickets key is rotated, in seconds. Default is 43200 (12h).
163 * ``sessionTickets``: bool - Whether session resumption via session tickets is enabled. Default is true, meaning tickets are enabled.
164 * ``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.
165 * ``ocspResponses``: list - List of files containing OCSP responses, in the same order than the certificates and keys, that will be used to provide OCSP stapling responses.
167 .. function:: setLocal(address[, options])
169 .. versionadded:: 1.2.0
171 Remove the list of listen addresses and add a new one.
173 :param str address: The IP Address with an optional port to listen on.
174 The default port is 53.
175 :param table options: A table with key: value pairs with listen options.
177 The options that can be set are the same as :func:`addLocal`.
179 .. function:: setLocal(address[[[,do_tcp], so_reuseport], tcp_fast_open_qsize])
181 .. deprecated:: 1.2.0
183 Remove the list of listen addresses and add a new one.
185 :param str address: The IP Address with an optional port to listen on.
186 The default port is 53.
187 :param bool do_tcp: Also bind a TCP port on ``address``, defaults to true.
188 :param bool so_reuseport: Use ``SO_REUSEPORT`` if it is available, defaults to false
189 :param int tcp_fast_open_qsize: The size of the TCP Fast Open queue. Set to a number
190 higher than 0 to enable TCP Fast Open when available.
193 Control Socket, Console and Webserver
194 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
196 .. function:: addConsoleACL(netmask)
198 .. versionadded:: 1.3.0
200 Add a netmask to the existing console ACL, allowing remote clients to connect to the console. Please make sure that encryption
201 has been enabled with :func:`setKey` before doing so. The default is to only allow 127.0.0.1/8 and ::1/128.
203 :param str netmask: A CIDR netmask, e.g. ``"192.0.2.0/24"``. Without a subnetmask, only the specific address is allowed.
205 .. function:: controlSocket(address)
207 Bind to ``addr`` and listen for a connection for the console. Since 1.3.0 only connections from local users are allowed
208 by default, :func:`addConsoleACL` and :func:`setConsoleACL` can be used to enable remote connections. Please make sure
209 that encryption has been enabled with :func:`setKey` before doing so. Enabling encryption is also strongly advised for
210 local connections, since not enabling it allows any local user to connect to the console.
212 :param str address: An IP address with optional port. By default, the port is 5199.
214 .. function:: inClientStartup()
216 Returns true while the console client is parsing the configuration.
218 .. function:: makeKey()
220 Generate and print an encryption key.
222 .. function:: setConsoleConnectionsLogging(enabled)
224 .. versionadded:: 1.2.0
226 Whether to log the opening and closing of console connections.
228 :param bool enabled: Default to true.
230 .. function:: setKey(key)
232 Use ``key`` as shared secret between the client and the server
234 :param str key: An encoded key, as generated by :func:`makeKey`
236 .. function:: setConsoleACL(netmasks)
238 .. versionadded:: 1.3.0
240 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
241 has been enabled with :func:`setKey` before doing so.
243 :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.
245 .. function:: showConsoleACL()
247 Print a list of all netmasks allowed to connect to the console.
249 .. function:: testCrypto()
251 Test the crypto code, will report errors when something is not ok.
253 .. function:: setConsoleOutputMaxMsgSize(size)
255 .. versionadded:: 1.3.3
257 Set the maximum size in bytes of a single console message, default set to 10 MB.
259 :param int size: The new maximum size.
261 Webserver configuration
262 ~~~~~~~~~~~~~~~~~~~~~~~
264 .. function:: webserver(listen_address, password[, apikey[, custom_headers]])
266 Launch the :doc:`../guides/webserver` with statistics and the API.
268 :param str listen_address: The IP address and Port to listen on
269 :param str password: The password required to access the webserver
270 :param str apikey: The key required to access the API
271 :param {[str]=str,...} custom_headers: Allows setting custom headers and removing the defaults
273 .. function:: setAPIWritable(allow [,dir])
275 Allow modifications via the API.
276 Optionally saving these changes to disk.
277 Modifications done via the API will not be written to the configuration by default and will not persist after a reload
279 :param bool allow: Set to true to allow modification through the API
280 :param str dir: A valid directory where the configuration files will be written by the API.
282 .. function:: setWebserverConfig(options)
284 .. versionadded:: 1.3.3
286 Setup webserver configuration. See :func:`webserver`.
288 :param table options: A table with key: value pairs with webserver options.
292 * ``password=newPassword``: string - Changes the API password
293 * ``apikey=newKey``: string - Changes the API Key (set to an empty string do disable it)
294 * ``custom_headers={[str]=str,...}``: map of string - Allows setting custom headers and removing the defaults.
299 .. function:: addACL(netmask)
301 Add a netmask to the existing ACL controlling which clients can send UDP, TCP, DNS over TLS and DNS over HTTPS queries. See :ref:`ACL` for more information.
303 :param str netmask: A CIDR netmask, e.g. ``"192.0.2.0/24"``. Without a subnetmask, only the specific address is allowed.
305 .. function:: setACL(netmasks)
307 Remove the existing ACL and add the netmasks from the table of those allowed to send UDP, TCP, DNS over TLS and DNS over HTTPS queries. See :ref:`ACL` for more information.
309 :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.
311 .. function:: showACL()
313 Print a list of all netmasks allowed to send queries over UDP, TCP, DNS over TLS and DNS over HTTPS. See :ref:`ACL` for more information.
318 .. function:: setECSOverride(bool)
320 When ``useClientSubnet`` in :func:`newServer` is set and dnsdist adds an EDNS Client Subnet Client option to the query, override an existing option already present in the query, if any
322 :param bool: Whether to override an existing EDNS Client Subnet option present in the query. Defaults to false
324 .. function:: setECSSourcePrefixV4(prefix)
326 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
328 :param int prefix: The prefix length
330 .. function:: setECSSourcePrefixV6(prefix)
332 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
334 :param int prefix: The prefix length
339 .. function:: setRingBuffersLockRetries(num)
341 .. versionadded:: 1.3.0
343 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
345 :param int num: The maximum number of attempts. Defaults to 5 if there is more than one shard, 0 otherwise.
347 .. function:: setRingBuffersSize(num [, numberOfShards])
349 .. versionchanged:: 1.3.0
350 ``numberOfShards`` optional parameter added.
352 Set the capacity of the ringbuffers used for live traffic inspection to ``num``, and the number of shards to ``numberOfShards`` if specified.
354 :param int num: The maximum amount of queries to keep in the ringbuffer. Defaults to 10000
355 :param int numberOfShards: the number of shards to use to limit lock contention. Defaults to 1
360 .. function:: newServer(server_string)
361 newServer(server_table)
363 .. versionchanged:: 1.3.0
364 Added ``checkClass``, ``sockets`` and ``checkFunction`` to server_table.
366 .. versionchanged:: 1.4.0
367 Added ``checkInterval``, ``checkTimeout`` and ``rise`` to server_table.
369 Add a new backend server. Call this function with either a string::
372 "IP:PORT" -- IP and PORT of the backend server
378 address="IP:PORT", -- IP and PORT of the backend server (mandatory)
379 id=STRING, -- Use a pre-defined UUID instead of a random one
380 qps=NUM, -- Limit the number of queries per second to NUM, when using the `firstAvailable` policy
381 order=NUM, -- The order of this server, used by the `leastOutstanding` and `firstAvailable` policies
382 weight=NUM, -- The weight of this server, used by the `wrandom`, `whashed` and `chashed` policies, default: 1
383 -- Supported values are a minimum of 1, and a maximum of 2147483647.
384 pool=STRING|{STRING}, -- The pools this server belongs to (unset or empty string means default pool) as a string or table of strings
385 retries=NUM, -- The number of TCP connection attempts to the backend, for a given query
386 tcpConnectTimeout=NUM, -- The timeout (in seconds) of a TCP connection attempt
387 tcpSendTimeout=NUM, -- The timeout (in seconds) of a TCP write attempt
388 tcpRecvTimeout=NUM, -- The timeout (in seconds) of a TCP read attempt
389 tcpFastOpen=BOOL, -- Whether to enable TCP Fast Open
390 ipBindAddrNoPort=BOOL, -- Whether to enable IP_BIND_ADDRESS_NO_PORT if available, default: true
391 name=STRING, -- The name associated to this backend, for display purpose
392 checkClass=NUM, -- Use NUM as QCLASS in the health-check query, default: DNSClass.IN
393 checkName=STRING, -- Use STRING as QNAME in the health-check query, default: "a.root-servers.net."
394 checkType=STRING, -- Use STRING as QTYPE in the health-check query, default: "A"
395 checkFunction=FUNCTION,-- Use this function to dynamically set the QNAME, QTYPE and QCLASS to use in the health-check query (see :ref:`Healthcheck`)
396 checkTimeout=NUM, -- The timeout (in milliseconds) of a health-check query, default: 1000 (1s)
397 setCD=BOOL, -- Set the CD (Checking Disabled) flag in the health-check query, default: false
398 maxCheckFailures=NUM, -- Allow NUM check failures before declaring the backend down, default: 1
399 checkInterval=NUM -- The time in seconds between health checks
400 mustResolve=BOOL, -- Set to true when the health check MUST return a RCODE different from NXDomain, ServFail and Refused. Default is false, meaning that every RCODE except ServFail is considered valid
401 useClientSubnet=BOOL, -- Add the client's IP address in the EDNS Client Subnet option when forwarding the query to this backend
402 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
403 -- The following formats are supported:
404 -- "address", e.g. "192.0.2.2"
405 -- "interface name", e.g. "eth0"
406 -- "address@interface", e.g. "192.0.2.2@eth0"
407 addXPF=NUM, -- Add the client's IP address and port to the query, along with the original destination address and port,
408 -- 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)
409 sockets=NUM, -- Number of sockets (and thus source ports) used toward the backend server, defaults to a single one
410 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
411 rise=NUM -- Require NUM consecutive successful checks before declaring the backend up, default: 1
414 :param str server_string: A simple IP:PORT string.
415 :param table server_table: A table with at least a 'name' key
417 .. function:: getServer(index) -> Server
419 Get a :class:`Server`
421 :param int index: The number of the server (as seen in :func:`showServers`).
422 :returns: The :class:`Server` object or nil
424 .. function:: getServers()
426 Returns a table with all defined servers.
428 .. function:: rmServer(index)
431 Remove a backend server.
433 :param int index: The number of the server (as seen in :func:`showServers`).
434 :param Server server: A :class:`Server` object as returned by e.g. :func:`getServer`.
438 A server object returned by :func:`getServer` can be manipulated with these functions.
442 This object represents a backend server. It has several methods.
444 .. method:: Server:addPool(pool)
446 Add this server to a pool.
448 :param str pool: The pool to add the server to
450 .. method:: Server:getName() -> string
452 Get the name of this server.
454 :returns: The name of the server, or an empty string if it does not have one
456 .. method:: Server:getNameWithAddr() -> string
458 Get the name plus IP address and port of the server
460 :returns: A string containing the server name if any plus the server address and port
462 .. method:: Server:getOutstanding() -> int
464 Get the number of outstanding queries for this server.
466 :returns: The number of outstanding queries
468 .. method:: Server:isUp() -> bool
470 Returns the up status of the server
472 :returns: true when the server is up, false otherwise
474 .. method:: Server:rmPool(pool)
476 Removes the server from the named pool
478 :param str pool: The pool to remove the server from
480 .. method:: Server:setAuto([status])
482 .. versionchanged:: 1.3.0
483 ``status`` optional parameter added.
485 Set the server in the default auto state.
486 This will enable health check queries that will set the server ``up`` and ``down`` appropriately.
488 :param bool status: Set the initial status of the server to ``up`` (true) or ``down`` (false) instead of using the last known status
490 .. method:: Server:setQPS(limit)
492 Limit the queries per second for this server.
494 :param int limit: The maximum number of queries per second
496 .. method:: Server:setDown()
498 Set the server in an ``DOWN`` state.
499 The server will not receive queries and the health checks are disabled
501 .. method:: Server:setUp()
503 Set the server in an ``UP`` state.
504 This server will still receive queries and health checks are disabled
506 Apart from the functions, a :class:`Server` object has these attributes:
508 .. attribute:: Server.name
510 The name of the server
512 .. attribute:: Server.upStatus
514 Whether or not this server is up or down
516 .. attribute:: Server.order
518 The order of the server
520 .. attribute:: Server.weight
522 The weight of the server
527 :class:`Server`\ s can be part of any number of pools.
528 Pools are automatically created when a server is added to a pool (with :func:`newServer`), or can be manually created with :func:`addPool`.
530 .. function:: addPool(name) -> ServerPool
532 Returns a :class:`ServerPool`.
534 :param string name: The name of the pool to create
536 .. function:: getPool(name) -> ServerPool
538 Returns a :class:`ServerPool` or nil.
540 :param string name: The name of the pool
542 .. function:: getPoolServers(name) -> [ Server ]
544 Returns a list of :class:`Server`\ s or nil.
546 :param string name: The name of the pool
548 .. function:: showPools()
550 Display the name, associated cache, server policy and associated servers for every pool.
552 .. class:: ServerPool
554 This represents the pool where zero or more servers are part of.
556 .. method:: ServerPool:getCache() -> PacketCache
558 Returns the :class:`PacketCache` for this pool or nil.
560 .. method:: ServerPool:getECS()
562 .. versionadded:: 1.3.0
564 Whether dnsdist will add EDNS Client Subnet information to the query before looking up into the cache,
565 when all servers from this pool are down. For more information see :meth:`ServerPool:setECS`.
567 .. method:: ServerPool:setCache(cache)
569 Adds ``cache`` as the pool's cache.
571 :param PacketCache cache: The new cache to add to the pool
573 .. method:: ServerPool:unsetCache()
575 Removes the cache from this pool.
577 .. method:: ServerPool:setECS()
579 .. versionadded:: 1.3.0
581 Set to true if dnsdist should add EDNS Client Subnet information to the query before looking up into the cache,
582 when all servers from this pool are down. If at least one server is up, the preference of the
583 selected server is used, this parameter is only useful if all the backends in this pool are down
584 and have EDNS Client Subnet enabled, since the queries in the cache will have been inserted with
585 ECS information. Default is false.
590 A Pool can have a packet cache to answer queries directly instead of going to the backend.
591 See :doc:`../guides/cache` for a how to.
593 .. function:: newPacketCache(maxEntries[, maxTTL=86400[, minTTL=0[, temporaryFailureTTL=60[, staleTTL=60[, dontAge=false[, numberOfShards=1[, deferrableInsertLock=true[, maxNegativeTTL=3600[, parseECS=false]]]]]]]) -> PacketCache
595 .. versionchanged:: 1.3.0
596 ``numberOfShards`` and ``deferrableInsertLock`` parameters added.
598 .. versionchanged:: 1.3.1
599 ``maxNegativeTTL`` and ``parseECS`` parameters added.
601 .. deprecated:: 1.4.0
603 Creates a new :class:`PacketCache` with the settings specified.
605 :param int maxEntries: The maximum number of entries in this cache
606 :param int maxTTL: Cap the TTL for records to his number
607 :param int minTTL: Don't cache entries with a TTL lower than this
608 :param int temporaryFailureTTL: On a SERVFAIL or REFUSED from the backend, cache for this amount of seconds
609 :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
610 :param bool dontAge: Don't reduce TTLs when serving from the cache. Use this when :program:`dnsdist` fronts a cluster of authoritative servers
611 :param int numberOfShards: Number of shards to divide the cache into, to reduce lock contention
612 :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
613 :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
614 :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
616 .. function:: newPacketCache(maxEntries, [options]) -> PacketCache
618 .. versionadded:: 1.4.0
620 Creates a new :class:`PacketCache` with the settings specified.
622 :param int maxEntries: The maximum number of entries in this cache
626 * ``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.
627 * ``dontAge=false``: bool - Don't reduce TTLs when serving from the cache. Use this when :program:`dnsdist` fronts a cluster of authoritative servers.
628 * ``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.
629 * ``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.
630 * ``maxTTL=86400``: int - Cap the TTL for records to his number.
631 * ``minTTL=0``: int - Don't cache entries with a TTL lower than this.
632 * ``numberOfShards=1``: int - Number of shards to divide the cache into, to reduce lock contention.
633 * ``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.
634 * ``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.
635 * ``temporaryFailureTTL=60``: int - On a SERVFAIL or REFUSED from the backend, cache for this amount of seconds..
637 .. class:: PacketCache
639 Represents a cache that can be part of :class:`ServerPool`.
641 .. method:: PacketCache:dump(fname)
643 .. versionadded:: 1.3.1
645 Dump a summary of the cache entries to a file.
647 :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.
649 .. method:: PacketCache:expunge(n)
651 Remove entries from the cache, leaving at most ``n`` entries
653 :param int n: Number of entries to keep
655 .. method:: PacketCache:expungeByName(name [, qtype=DNSQType.ANY[, suffixMatch=false]])
657 .. versionchanged:: 1.2.0
658 ``suffixMatch`` parameter added.
660 Remove entries matching ``name`` and type from the cache.
662 :param DNSName name: The name to expunge
663 :param int qtype: The type to expunge, can be a pre-defined :ref:`DNSQType`
664 :param bool suffixMatch: When set to true, remove al entries under ``name``
666 .. method:: PacketCache:getStats()
668 .. versionadded:: 1.4.0
670 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.
672 .. method:: PacketCache:isFull() -> bool
674 Return true if the cache has reached the maximum number of entries.
676 .. method:: PacketCache:printStats()
678 Print the cache stats (number of entries, hits, misses, deferred lookups, deferred inserts, lookup collisions, insert collisions and TTL too shorts).
680 .. method:: PacketCache:purgeExpired(n)
682 Remove expired entries from the cache until there is at most ``n`` entries remaining in the cache.
684 :param int n: Number of entries to keep
686 .. method:: PacketCache:toString() -> string
688 Return the number of entries in the Packet Cache, and the maximum number of entries
693 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.
695 .. function:: getBind(index) -> ClientState
697 Return a :class:`ClientState` object.
699 :param int index: The object index
701 ClientState functions
702 ~~~~~~~~~~~~~~~~~~~~~
704 .. class:: ClientState
706 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.
708 .. method:: ClientState:attachFilter(filter)
710 Attach a BPF filter to this frontend.
712 :param BPFFilter filter: The filter to attach to this frontend
714 .. method:: ClientState:detachFilter()
716 Remove the BPF filter associated to this frontend, if any.
718 .. method:: ClientState:toString() -> string
720 Return the address and port this frontend is listening on.
722 :returns: The address and port this frontend is listening on
724 .. attribute:: ClientState.muted
726 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.
728 Status, Statistics and More
729 ---------------------------
731 .. function:: dumpStats()
733 Print all statistics dnsdist gathers
735 .. function:: getDOHFrontend(idx)
737 .. versionadded:: 1.4.0
739 Return the DOHFrontend object for the DNS over HTTPS bind of index ``idx``.
741 .. function:: getTLSContext(idx)
743 .. versionadded:: 1.3.0
745 Return the TLSContext object for the context of index ``idx``.
747 .. function:: getTLSFrontend(idx)
749 .. versionadded:: 1.3.1
751 Return the TLSFrontend object for the TLS bind of index ``idx``.
753 .. function:: grepq(selector[, num])
754 grepq(selectors[, num])
756 Prints the last ``num`` queries matching ``selector`` or ``selectors``.
760 * a netmask (e.g. '192.0.2.0/24')
761 * a DNS name (e.g. 'dnsdist.org')
762 * a response time (e.g. '100ms')
764 :param str selector: Select queries based on this property.
765 :param {str} selectors: A lua table of selectors. Only queries matching all selectors are shown
766 :param int num: Show a maximum of ``num`` recent queries, default is 10.
768 .. function:: setVerboseHealthChecks(verbose)
770 Set whether health check errors should be logged. This is turned off by default.
772 :param bool verbose: Set to true if you want to enable health check errors logging
774 .. function:: showBinds()
776 Print a list of all the current addresses and ports dnsdist is listening on, also called ``frontends``
778 .. function:: showDOHFrontends()
780 .. versionadded:: 1.4.0
782 Print the list of all availables DNS over HTTPS frontends.
784 .. function:: showDOHResponseCodes()
786 .. versionadded:: 1.4.0
788 Print the HTTP response codes statistics for all availables DNS over HTTPS frontends.
790 .. function:: showResponseLatency()
792 Show a plot of the response time latency distribution
794 .. function:: showServers([options])
796 .. versionchanged:: 1.4.0
797 ``options`` optional parameter added
799 This function shows all backend servers currently configured and some statistics.
800 These statics have the following fields:
802 * ``#`` - The number of the server, can be used as the argument for :func:`getServer`
803 * ``UUID`` - The UUID of the backend. Can be set with the ``id`` option of :func:`newServer`
804 * ``Address`` - The IP address and port of the server
805 * ``State`` - The current state of the server
806 * ``Qps`` - Current number of queries per second
807 * ``Qlim`` - Configured maximum number of queries per second
808 * ``Ord`` - The order number of the server
809 * ``Wt`` - The weight of the server
810 * ``Queries`` - Total amount of queries sent to this server
811 * ``Drops`` - Number of queries that were dropped by this server
812 * ``Drate`` - Number of queries dropped per second by this server
813 * ``Lat`` - The latency of this server in milliseconds
814 * ``Pools`` - The pools this server belongs to
816 :param table options: A table with key: value pairs with display options.
820 * ``showUUIDs=false``: bool - Whether to display the UUIDs, defaults to false.
822 .. function:: showTCPStats()
824 Show some statistics regarding TCP
826 .. function:: showTLSContexts()
828 .. versionadded:: 1.3.0
830 Print the list of all availables DNS over TLS contexts.
832 .. function:: showVersion()
834 Print the version of dnsdist
836 .. function:: topBandwidth([num])
838 Print the top ``num`` clients that consume the most bandwidth.
840 :param int num: Number to show, defaults to 10.
842 .. function:: topClients([num])
844 Print the top ``num`` clients sending the most queries over length of ringbuffer
846 :param int num: Number to show, defaults to 10.
848 .. function:: topQueries([num[, labels]])
850 Print the ``num`` most popular QNAMEs from queries.
851 Optionally grouped by the rightmost ``labels`` DNS labels.
853 :param int num: Number to show, defaults to 10
854 :param int label: Number of labels to cut down to
856 .. function:: topResponses([num[, rcode[, labels]]])
858 Print the ``num`` most seen responses with an RCODE of ``rcode``.
859 Optionally grouped by the rightmost ``labels`` DNS labels.
861 :param int num: Number to show, defaults to 10
862 :param int rcode: :ref:`Response code <DNSRCode>`, defaults to 0 (No Error)
863 :param int label: Number of labels to cut down to
865 .. function:: topSlow([num[, limit[, labels]]])
867 Print the ``num`` slowest queries that are slower than ``limit`` milliseconds.
868 Optionally grouped by the rightmost ``labels`` DNS labels.
870 :param int num: Number to show, defaults to 10
871 :param int limit: Show queries slower than this amount of milliseconds, defaults to 2000
872 :param int label: Number of labels to cut down to
879 .. function:: addDynBlocks(addresses, message[, seconds=10[, action]])
881 .. versionchanged:: 1.2.0
882 ``action`` parameter added.
884 Block a set of addresses with ``message`` for (optionally) a number of seconds.
885 The default number of seconds to block for is 10.
887 :param addresses: set of Addresses as returned by an exceed function
888 :param string message: The message to show next to the blocks
889 :param int seconds: The number of seconds this block to expire
890 :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)
892 Please see the documentation for :func:`setDynBlocksAction` to confirm which actions are supported by the action paramater.
894 .. function:: clearDynBlocks()
896 Remove all current dynamic blocks.
898 .. function:: showDynBlocks()
900 List all dynamic blocks in effect.
902 .. function:: setDynBlocksAction(action)
904 .. versionchanged:: 1.3.3
905 ``DNSAction.NXDomain`` action added.
907 Set which action is performed when a query is blocked.
908 Only DNSAction.Drop (the default), DNSAction.NoOp, DNSAction.NXDomain, DNSAction.Refused, DNSAction.Truncate and DNSAction.NoRecurse are supported.
912 Getting addresses that exceeded parameters
913 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
915 .. function:: exceedServFails(rate, seconds)
917 Get set of addresses that exceed ``rate`` servfails/s over ``seconds`` seconds
919 :param int rate: Number of Servfails per second to exceed
920 :param int seconds: Number of seconds the rate has been exceeded
922 .. function:: exceedNXDOMAINs(rate, seconds)
924 get set of addresses that exceed ``rate`` NXDOMAIN/s over ``seconds`` seconds
926 :param int rate: Number of NXDOMAIN per second to exceed
927 :param int seconds: Number of seconds the rate has been exceeded
929 .. function:: exceedRespByterate(rate, seconds)
931 get set of addresses that exceeded ``rate`` bytes/s answers over ``seconds`` seconds
933 :param int rate: Number of bytes per second to exceed
934 :param int seconds: Number of seconds the rate has been exceeded
936 .. function:: exceedQRate(rate, seconds)
938 Get set of address that exceed ``rate`` queries/s over ``seconds`` seconds
940 :param int rate: Number of queries per second to exceed
941 :param int seconds: Number of seconds the rate has been exceeded
943 .. function:: exceedQTypeRate(type, rate, seconds)
945 Get set of address that exceed ``rate`` queries/s for queries of QType ``type`` over ``seconds`` seconds
947 :param int type: QType
948 :param int rate: Number of QType queries per second to exceed
949 :param int seconds: Number of seconds the rate has been exceeded
954 Instead of using several `exceed*()` lines, dnsdist 1.3.0 introduced a new `DynBlockRulesGroup` object
955 which can be used to group dynamic block rules.
957 See :doc:`../guides/dynblocks` for more information about the case where using a `DynBlockRulesGroup` might be
958 faster than the existing rules.
960 .. function:: dynBlockRulesGroup() -> DynBlockRulesGroup
962 .. versionadded:: 1.3.0
964 Creates a new :class:`DynBlockRulesGroup` object.
966 .. class:: DynBlockRulesGroup
968 Represents a group of dynamic block rules.
970 .. method:: DynBlockRulesGroup:setQueryRate(rate, seconds, reason, blockingTime [, action [, warningRate]])
972 .. versionchanged:: 1.3.3
973 ``warningRate`` parameter added.
975 Adds a query rate-limiting rule, equivalent to:
977 addDynBlocks(exceedQRate(rate, seconds), reason, blockingTime, action)
980 :param int rate: Number of queries 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:setRCodeRate(rcode, rate, seconds, reason, blockingTime [, action [, warningRate]])
989 .. versionchanged:: 1.3.3
990 ``warningRate`` parameter added.
992 Adds a rate-limiting rule for responses of code ``rcode``, equivalent to:
994 addDynBlocks(exceedServfails(rcode, rate, seconds), reason, blockingTime, action)
997 :param int rcode: The response code
998 :param int rate: Number of responses 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:setQTypeRate(qtype, rate, seconds, reason, blockingTime [, action [, warningRate]])
1007 .. versionchanged:: 1.3.3
1008 ``warningRate`` parameter added.
1010 Adds a rate-limiting rule for queries of type ``qtype``, equivalent to:
1012 addDynBlocks(exceedQTypeRate(type, rate, seconds), reason, blockingTime, action)
1015 :param int qtype: The qtype
1016 :param int rate: Number of queries per second to exceed
1017 :param int seconds: Number of seconds the rate has been exceeded
1018 :param string reason: The message to show next to the blocks
1019 :param int blockingTime: The number of seconds this block to expire
1020 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
1021 :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
1023 .. method:: DynBlockRulesGroup:setResponseByteRate(rate, seconds, reason, blockingTime [, action [, warningRate]])
1025 .. versionchanged:: 1.3.3
1026 ``warningRate`` parameter added.
1028 Adds a bandwidth rate-limiting rule for responses, equivalent to:
1030 addDynBlocks(exceedRespByterate(rate, seconds), reason, blockingTime, action)
1033 :param int rate: Number of bytes per second to exceed
1034 :param int seconds: Number of seconds the rate has been exceeded
1035 :param string reason: The message to show next to the blocks
1036 :param int blockingTime: The number of seconds this block to expire
1037 :param int action: The action to take when the dynamic block matches, see :ref:`here <DNSAction>`. (default to the one set with :func:`setDynBlocksAction`)
1038 :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
1040 .. method:: DynBlockRulesGroup:apply()
1042 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.
1044 .. method:: DynBlockRulesGroup:excludeRange(netmasks)
1046 .. versionadded:: 1.3.1
1048 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.
1050 :param int netmasks: A netmask, or list of netmasks, as strings, like for example "192.0.2.1/24"
1052 .. method:: DynBlockRulesGroup:includeRange(netmasks)
1054 .. versionadded:: 1.3.1
1056 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.
1058 :param int netmasks: A netmask, or list of netmasks, as strings, like for example "192.0.2.1/24"
1060 .. method:: DynBlockRulesGroup:toString()
1062 .. versionadded:: 1.3.1
1064 Return a string describing the rules and range exclusions of this DynBlockRulesGroup.
1069 A SuffixMatchNode can be used to quickly check whether a given name belongs to a set or not. This is achieved
1070 using an efficient tree structure based on DNS labels, making lookups cheap.
1071 Be careful that Suffix Node matching will match for any sub-domain, regardless of the depth, under the name added to the set. For example,
1072 if 'example.com.' is added to the set, 'www.example.com.' and 'sub.www.example.com.' will match as well.
1073 If you are looking for exact name matching, your might want to consider using a :class:`DNSNameSet` instead.
1075 .. function:: newSuffixMatchNode()
1077 Creates a new :class:`SuffixMatchNode`.
1079 .. class:: SuffixMatchNode
1081 Represent a set of DNS suffixes for quick matching.
1083 .. method:: SuffixMatchNode:add(name)
1084 .. versionchanged:: 1.4.0
1085 This method now accepts strings, lists of DNSNames and lists of strings.
1087 Add a suffix to the current set.
1089 :param DNSName name: The suffix to add to the set.
1090 :param string name: The suffix to add to the set.
1091 :param table name: The suffixes to add to the set. Elements of the table should be of the same type, either DNSName or string.
1093 .. method:: SuffixMatchNode:check(name) -> bool
1095 Return true if the given name is a sub-domain of one of those in the set, and false otherwise.
1097 :param DNSName name: The name to test against the set.
1102 .. function:: maintenance()
1104 If this function exists, it is called every second to so regular tasks.
1105 This can be used for e.g. :doc:`Dynamic Blocks <../guides/dynblocks>`.
1107 .. function:: setAllowEmptyResponse()
1109 .. versionadded:: 1.4.0
1111 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.
1113 .. function:: makeIPCipherKey(password) -> string
1115 .. versionadded:: 1.4.0
1117 Hashes the password to generate a 16-byte key that can be used to pseudonymize IP addresses with IP cipher.
1119 .. function:: generateOCSPResponse(pathToServerCertificate, pathToCACertificate, pathToCAPrivateKey, outputFile, numberOfDaysOfValidity, numberOfMinutesOfValidity)
1121 .. versionadded:: 1.4.0
1123 When a local PKI is used to issue the certificate, or for testing purposes, :func:`generateOCSPResponse` can be used to generate an OCSP response file for a certificate, using the certificate and private key of the certification authority that signed that certificate.
1124 The resulting file can be directly used with the :func:`addDOHLocal` or the :func:`addTLSLocal` functions.
1126 :param string pathToServerCertificate: Path to a file containing the certificate used by the server.
1127 :param string pathToCACertificate: Path to a file containing the certificate of the certification authority that was used to sign the server certificate.
1128 :param string pathToCAPrivateKey: Path to a file containing the private key corresponding to the certification authority certificate.
1129 :param string outputFile: Path to a file where the resulting OCSP response will be written to.
1130 :param int numberOfDaysOfValidity: Number of days this OCSP response should be valid.
1131 :param int numberOfMinutesOfValidity: Number of minutes this OCSP response should be valid, in addition to the number of days.
1136 .. class:: DOHFrontend
1138 .. versionadded:: 1.4.0
1140 This object represents an address and port dnsdist is listening on for DNS over HTTPS queries.
1142 .. method:: DOHFrontend:reloadCertificates()
1144 Reload the current TLS certificate and key pairs.
1149 .. class:: TLSContext
1151 .. versionadded:: 1.3.0
1153 This object represents an address and port dnsdist is listening on for DNS over TLS queries.
1155 .. method:: TLSContext:rotateTicketsKey()
1157 Replace the current TLS tickets key by a new random one.
1159 .. method:: TLSContext:loadTicketsKeys(ticketsKeysFile)
1161 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.
1163 :param str ticketsKeysFile: The path to a file from where TLS tickets keys should be loaded.
1168 .. class:: TLSFrontend
1170 .. versionadded:: 1.3.1
1172 This object represents the configuration of a listening frontend for DNS over TLS queries. To each frontend is associated a TLSContext.
1174 .. method:: TLSContext:loadNewCertificatesAndKeys(certFile(s), keyFile(s))
1176 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.
1178 :param str certFile(s): The path to a X.509 certificate file in PEM format, or a list of paths to such files.
1179 :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.
1181 EDNS on Self-generated answers
1182 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1184 There are several mechanisms in dnsdist that turn an existing query into an answer right away,
1185 without reaching out to the backend, including :func:`SpoofAction`, :func:`RCodeAction`, :func:`TCAction`
1186 and returning a response from ``Lua``. Those responses should, according to :rfc:`6891`, contain an ``OPT``
1187 record if the received request had one, which is the case by default and can be disabled using
1188 :func:`setAddEDNSToSelfGeneratedResponses`.
1190 We must, however, provide a responder's maximum payload size in this record, and we can't easily know the
1191 maximum payload size of the actual backend so we need to provide one. The default value is 1500 and can be
1192 overriden using :func:`setPayloadSizeOnSelfGeneratedAnswers`.
1194 .. function:: setAddEDNSToSelfGeneratedResponses(add)
1196 .. versionadded:: 1.3.3
1198 Whether to add EDNS to self-generated responses, provided that the initial query had EDNS.
1200 :param bool add: Whether to add EDNS, default is true.
1202 .. function:: setPayloadSizeOnSelfGeneratedAnswers(payloadSize)
1204 .. versionadded:: 1.3.3
1206 Set the UDP payload size advertised via EDNS on self-generated responses. In accordance with
1207 :rfc:`RFC 6891 <6891#section-6.2.5>`, values lower than 512 will be treated as equal to 512.
1209 :param int payloadSize: The responder's maximum UDP payload size, in bytes. Default is 1500.
1214 PowerDNS products can poll the security status of their respective versions. This polling, naturally,
1215 happens over DNS. If the result is that a given version has a security problem, the software will
1216 report this at level ‘Error’ during startup, and repeatedly during operations, every
1217 :func:`setSecurityPollInterval` seconds.
1219 By default, security polling happens on the domain ‘secpoll.powerdns.com’, but this can be changed with
1220 the :func:`setSecurityPollSuffix` function. If this setting is made empty, no polling will take place.
1221 Organizations wanting to host their own security zones can do so by changing this setting to a domain name
1222 under their control.
1224 To enable distributors of PowerDNS to signal that they have backported versions, the PACKAGEVERSION
1225 compilation-time macro can be used to set a distributor suffix.
1227 .. function:: setSecurityPollInterval(interval)
1229 .. versionadded:: 1.3.3
1231 Set the interval, in seconds, between two security pollings.
1233 :param int interval: The interval, in seconds, between two pollings. Default is 3600.
1235 .. function:: setSecurityPollSuffix(suffix)
1237 .. versionadded:: 1.3.3
1239 Domain name from which to query security update notifications. Setting this to an empty string disables secpoll.
1241 :param string suffix: The suffix to use, default is 'secpoll.powerdns.com.'.