1 .TH "unbound.conf" "5" "Mar 10, 2015" "NLnet Labs" "unbound 1.5.3"
3 .\" unbound.conf.5 -- unbound.conf manual
5 .\" Copyright (c) 2007, NLnet Labs. All rights reserved.
7 .\" See LICENSE for the license.
12 \- Unbound configuration file.
19 The file format has attributes and values. Some attributes have attributes inside them.
20 The notation is: attribute: value.
22 Comments start with # and last to the end of line. Empty lines are
23 ignored as is whitespace at the beginning of a line.
26 \fIunbound\-checkconf\fR(8)
27 can be used to check unbound.conf prior to usage.
29 An example config file is shown below. Copy this to /etc/unbound/unbound.conf
30 and start the server with:
33 $ unbound \-c /etc/unbound/unbound.conf
36 Most settings are the defaults. Stop the server with:
39 $ kill `cat /etc/unbound/unbound.pid`
42 Below is a minimal config file. The source distribution contains an extensive
43 example.conf file with all the options.
46 # unbound.conf(5) config file for unbound(8).
48 directory: "/etc/unbound"
50 # make sure unbound can access entropy from inside the chroot.
51 # e.g. on linux the use these commands (on BSD, devfs(8) is used):
52 # mount \-\-bind \-n /dev/random /etc/unbound/dev/random
53 # and mount \-\-bind \-n /dev/log /etc/unbound/dev/log
54 chroot: "/etc/unbound"
55 # logfile: "/etc/unbound/unbound.log" #uncomment to use logfile.
56 pidfile: "/etc/unbound/unbound.pid"
57 # verbosity: 1 # uncomment and increase to get more logging.
58 # listen on all interfaces, answer queries from the local subnet.
61 access\-control: 10.0.0.0/8 allow
62 access\-control: 2001:DB8::/64 allow
65 There must be whitespace between keywords. Attribute keywords end with a colon ':'. An attribute
66 is followed by its containing attributes, or a value.
68 Files can be included using the
70 directive. It can appear anywhere, it accepts a single file name as argument.
71 Processing continues as if the text from the included file was copied into
72 the config file at that point. If also using chroot, using full path names
73 for the included files works, relative pathnames for the included names work
74 if the directory where the daemon is started equals its chroot/working
75 directory. Wildcards can be used to include multiple files, see \fIglob\fR(7).
77 These options are part of the
81 .B verbosity: \fI<number>
82 The verbosity number, level 0 means no verbosity, only errors. Level 1
83 gives operational information. Level 2 gives detailed operational
84 information. Level 3 gives query level information, output per query.
85 Level 4 gives algorithm level information. Level 5 logs client
86 identification for cache misses. Default is level 1.
87 The verbosity can also be increased from the commandline, see \fIunbound\fR(8).
89 .B statistics\-interval: \fI<seconds>
90 The number of seconds between printing statistics to the log for every thread.
91 Disable with value 0 or "". Default is disabled. The histogram statistics
92 are only printed if replies were sent during the statistics interval,
93 requestlist statistics are printed for every interval (but can be 0).
94 This is because the median calculation requires data to be present.
96 .B statistics\-cumulative: \fI<yes or no>
97 If enabled, statistics are cumulative since starting unbound, without clearing
98 the statistics counters after logging the statistics. Default is no.
100 .B extended\-statistics: \fI<yes or no>
101 If enabled, extended statistics are printed from \fIunbound\-control\fR(8).
102 Default is off, because keeping track of more statistics takes time. The
103 counters are listed in \fIunbound\-control\fR(8).
105 .B num\-threads: \fI<number>
106 The number of threads to create to serve clients. Use 1 for no threading.
108 .B port: \fI<port number>
109 The port number, default 53, on which the server responds to queries.
111 .B interface: \fI<ip address[@port]>
112 Interface to use to connect to the network. This interface is listened to
113 for queries from clients, and answers to clients are given from it.
114 Can be given multiple times to work on several interfaces. If none are
115 given the default is to listen to localhost.
116 The interfaces are not changed on a reload (kill \-HUP) but only on restart.
117 A port number can be specified with @port (without spaces between
118 interface and port number), if not specified the default port (from
121 .B ip\-address: \fI<ip address[@port]>
122 Same as interface: (for easy of compatibility with nsd.conf).
124 .B interface\-automatic: \fI<yes or no>
125 Detect source interface on UDP queries and copy them to replies. This
126 feature is experimental, and needs support in your OS for particular socket
127 options. Default value is no.
129 .B outgoing\-interface: \fI<ip address>
130 Interface to use to connect to the network. This interface is used to send
131 queries to authoritative servers and receive their replies. Can be given
132 multiple times to work on several interfaces. If none are given the
133 default (all) is used. You can specify the same interfaces in
136 .B outgoing\-interface:
137 lines, the interfaces are then used for both purposes. Outgoing queries are
138 sent via a random outgoing interface to counter spoofing.
140 .B outgoing\-range: \fI<number>
141 Number of ports to open. This number of file descriptors can be opened per
142 thread. Must be at least 1. Default depends on compile options. Larger
143 numbers need extra resources from the operating system. For performance a
144 a very large value is best, use libevent to make this possible.
146 .B outgoing\-port\-permit: \fI<port number or range>
147 Permit unbound to open this port or range of ports for use to send queries.
148 A larger number of permitted outgoing ports increases resilience against
149 spoofing attempts. Make sure these ports are not needed by other daemons.
150 By default only ports above 1024 that have not been assigned by IANA are used.
151 Give a port number or a range of the form "low\-high", without spaces.
153 The \fBoutgoing\-port\-permit\fR and \fBoutgoing\-port\-avoid\fR statements
154 are processed in the line order of the config file, adding the permitted ports
155 and subtracting the avoided ports from the set of allowed ports. The
156 processing starts with the non IANA allocated ports above 1024 in the set
159 .B outgoing\-port\-avoid: \fI<port number or range>
160 Do not permit unbound to open this port or range of ports for use to send
161 queries. Use this to make sure unbound does not grab a port that another
162 daemon needs. The port is avoided on all outgoing interfaces, both IP4 and IP6.
163 By default only ports above 1024 that have not been assigned by IANA are used.
164 Give a port number or a range of the form "low\-high", without spaces.
166 .B outgoing\-num\-tcp: \fI<number>
167 Number of outgoing TCP buffers to allocate per thread. Default is 10. If set
168 to 0, or if do\-tcp is "no", no TCP queries to authoritative servers are done.
170 .B incoming\-num\-tcp: \fI<number>
171 Number of incoming TCP buffers to allocate per thread. Default is 10. If set
172 to 0, or if do\-tcp is "no", no TCP queries from clients are accepted.
174 .B edns\-buffer\-size: \fI<number>
175 Number of bytes size to advertise as the EDNS reassembly buffer size.
176 This is the value put into datagrams over UDP towards peers. The actual
177 buffer size is determined by msg\-buffer\-size (both for TCP and UDP). Do
178 not set higher than that value. Default is 4096 which is RFC recommended.
179 If you have fragmentation reassembly problems, usually seen as timeouts,
180 then a value of 1480 can fix it. Setting to 512 bypasses even the most
181 stringent path MTU problems, but is seen as extreme, since the amount
182 of TCP fallback generated is excessive (probably also for this resolver,
183 consider tuning the outgoing tcp number).
185 .B max\-udp\-size: \fI<number>
186 Maximum UDP response size (not applied to TCP response). 65536 disables the
187 udp response size maximum, and uses the choice from the client, always.
188 Suggested values are 512 to 4096. Default is 4096.
190 .B msg\-buffer\-size: \fI<number>
191 Number of bytes size of the message buffers. Default is 65552 bytes, enough
192 for 64 Kb packets, the maximum DNS message size. No message larger than this
193 can be sent or received. Can be reduced to use less memory, but some requests
194 for DNS data, such as for huge resource records, will result in a SERVFAIL
197 .B msg\-cache\-size: \fI<number>
198 Number of bytes size of the message cache. Default is 4 megabytes.
199 A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
200 or gigabytes (1024*1024 bytes in a megabyte).
202 .B msg\-cache\-slabs: \fI<number>
203 Number of slabs in the message cache. Slabs reduce lock contention by threads.
204 Must be set to a power of 2. Setting (close) to the number of cpus is a
207 .B num\-queries\-per\-thread: \fI<number>
208 The number of queries that every thread will service simultaneously.
209 If more queries arrive that need servicing, and no queries can be jostled out
210 (see \fIjostle\-timeout\fR), then the queries are dropped. This forces
211 the client to resend after a timeout; allowing the server time to work on
212 the existing queries. Default depends on compile options, 512 or 1024.
214 .B jostle\-timeout: \fI<msec>
215 Timeout used when the server is very busy. Set to a value that usually
216 results in one roundtrip to the authority servers. If too many queries
217 arrive, then 50% of the queries are allowed to run to completion, and
218 the other 50% are replaced with the new incoming query if they have already
219 spent more than their allowed time. This protects against denial of
220 service by slow queries or high query rates. Default 200 milliseconds.
221 The effect is that the qps for long-lasting queries is about
222 (numqueriesperthread / 2) / (average time for such long queries) qps.
223 The qps for short queries can be about (numqueriesperthread / 2)
224 / (jostletimeout in whole seconds) qps per thread, about (1024/2)*5 = 2560
227 .B delay\-close: \fI<msec>
228 Extra delay for timeouted UDP ports before they are closed, in msec.
229 Default is 0, and that disables it. This prevents very delayed answer
230 packets from the upstream (recursive) servers from bouncing against
231 closed ports and setting off all sort of close-port counters, with
232 eg. 1500 msec. When timeouts happen you need extra sockets, it checks
233 the ID and remote IP of packets, and unwanted packets are added to the
234 unwanted packet counter.
236 .B so\-rcvbuf: \fI<number>
237 If not 0, then set the SO_RCVBUF socket option to get more buffer
238 space on UDP port 53 incoming queries. So that short spikes on busy
239 servers do not drop packets (see counter in netstat \-su). Default is
240 0 (use system value). Otherwise, the number of bytes to ask for, try
241 "4m" on a busy server. The OS caps it at a maximum, on linux unbound
242 needs root permission to bypass the limit, or the admin can use sysctl
243 net.core.rmem_max. On BSD change kern.ipc.maxsockbuf in /etc/sysctl.conf.
244 On OpenBSD change header and recompile kernel. On Solaris ndd \-set
245 /dev/udp udp_max_buf 8388608.
247 .B so\-sndbuf: \fI<number>
248 If not 0, then set the SO_SNDBUF socket option to get more buffer space on
249 UDP port 53 outgoing queries. This for very busy servers handles spikes
250 in answer traffic, otherwise 'send: resource temporarily unavailable'
251 can get logged, the buffer overrun is also visible by netstat \-su.
252 Default is 0 (use system value). Specify the number of bytes to ask
253 for, try "4m" on a very busy server. The OS caps it at a maximum, on
254 linux unbound needs root permission to bypass the limit, or the admin
255 can use sysctl net.core.wmem_max. On BSD, Solaris changes are similar
258 .B so\-reuseport: \fI<yes or no>
259 If yes, then open dedicated listening sockets for incoming queries for each
260 thread and try to set the SO_REUSEPORT socket option on each socket. May
261 distribute incoming queries to threads more evenly. Default is no. On Linux
262 it is supported in kernels >= 3.9. On other systems, FreeBSD, OSX it may
263 also work. You can enable it (on any platform and kernel),
264 it then attempts to open the port and passes the option if it was available
265 at compile time, if that works it is used, if it fails, it continues
266 silently (unless verbosity 3) without the option.
268 .B rrset\-cache\-size: \fI<number>
269 Number of bytes size of the RRset cache. Default is 4 megabytes.
270 A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
271 or gigabytes (1024*1024 bytes in a megabyte).
273 .B rrset\-cache\-slabs: \fI<number>
274 Number of slabs in the RRset cache. Slabs reduce lock contention by threads.
275 Must be set to a power of 2.
277 .B cache\-max\-ttl: \fI<seconds>
278 Time to live maximum for RRsets and messages in the cache. Default is
279 86400 seconds (1 day). If the maximum kicks in, responses to clients
280 still get decrementing TTLs based on the original (larger) values.
281 When the internal TTL expires, the cache item has expired.
282 Can be set lower to force the resolver to query for data often, and not
283 trust (very large) TTL values.
285 .B cache\-min\-ttl: \fI<seconds>
286 Time to live minimum for RRsets and messages in the cache. Default is 0.
287 If the the minimum kicks in, the data is cached for longer than the domain
288 owner intended, and thus less queries are made to look up the data.
289 Zero makes sure the data in the cache is as the domain owner intended,
290 higher values, especially more than an hour or so, can lead to trouble as
291 the data in the cache does not match up with the actual data any more.
293 .B infra\-host\-ttl: \fI<seconds>
294 Time to live for entries in the host cache. The host cache contains
295 roundtrip timing, lameness and EDNS support information. Default is 900.
297 .B infra\-cache\-slabs: \fI<number>
298 Number of slabs in the infrastructure cache. Slabs reduce lock contention
299 by threads. Must be set to a power of 2.
301 .B infra\-cache\-numhosts: \fI<number>
302 Number of hosts for which information is cached. Default is 10000.
304 .B infra\-cache\-min\-rtt: \fI<msec>
305 Lower limit for dynamic retransmit timeout calculation in infrastructure
306 cache. Default is 50 milliseconds. Increase this value if using forwarders
307 needing more time to do recursive name resolution.
309 .B do\-ip4: \fI<yes or no>
310 Enable or disable whether ip4 queries are answered or issued. Default is yes.
312 .B do\-ip6: \fI<yes or no>
313 Enable or disable whether ip6 queries are answered or issued. Default is yes.
314 If disabled, queries are not answered on IPv6, and queries are not sent on
315 IPv6 to the internet nameservers. With this option you can disable the
316 ipv6 transport for sending DNS traffic, it does not impact the contents of
317 the DNS traffic, which may have ip4 and ip6 addresses in it.
319 .B do\-udp: \fI<yes or no>
320 Enable or disable whether UDP queries are answered or issued. Default is yes.
322 .B do\-tcp: \fI<yes or no>
323 Enable or disable whether TCP queries are answered or issued. Default is yes.
325 .B tcp\-upstream: \fI<yes or no>
326 Enable or disable whether the upstream queries use TCP only for transport.
327 Default is no. Useful in tunneling scenarios.
329 .B ssl\-upstream: \fI<yes or no>
330 Enabled or disable whether the upstream queries use SSL only for transport.
331 Default is no. Useful in tunneling scenarios. The SSL contains plain DNS in
332 TCP wireformat. The other server must support this (see \fBssl\-service\-key\fR).
334 .B ssl\-service-key: \fI<file>
335 If enabled, the server provider SSL service on its TCP sockets. The clients
336 have to use ssl\-upstream: yes. The file is the private key for the TLS
337 session. The public certificate is in the ssl\-service\-pem file. Default
338 is "", turned off. Requires a restart (a reload is not enough) if changed,
339 because the private key is read while root permissions are held and before
340 chroot (if any). Normal DNS TCP service is not provided and gives errors,
341 this service is best run with a different \fBport:\fR config or \fI@port\fR
342 suffixes in the \fBinterface\fR config.
344 .B ssl\-service\-pem: \fI<file>
345 The public key certificate pem file for the ssl service. Default is "",
348 .B ssl\-port: \fI<number>
349 The port number on which to provide TCP SSL service, default 443, only
350 interfaces configured with that port number as @number get the SSL service.
352 .B do\-daemonize: \fI<yes or no>
353 Enable or disable whether the unbound server forks into the background as
354 a daemon. Default is yes.
356 .B access\-control: \fI<IP netblock> <action>
357 The netblock is given as an IP4 or IP6 address with /size appended for a
358 classless network block. The action can be \fIdeny\fR, \fIrefuse\fR,
359 \fIallow\fR, \fIallow_snoop\fR, \fIdeny_non_local\fR or \fIrefuse_non_local\fR.
361 The action \fIdeny\fR stops queries from hosts from that netblock.
363 The action \fIrefuse\fR stops queries too, but sends a DNS rcode REFUSED
366 The action \fIallow\fR gives access to clients from that netblock.
367 It gives only access for recursion clients (which is
368 what almost all clients need). Nonrecursive queries are refused.
370 The \fIallow\fR action does allow nonrecursive queries to access the
371 local\-data that is configured. The reason is that this does not involve
372 the unbound server recursive lookup algorithm, and static data is served
373 in the reply. This supports normal operations where nonrecursive queries
374 are made for the authoritative data. For nonrecursive queries any replies
375 from the dynamic cache are refused.
377 The action \fIallow_snoop\fR gives nonrecursive access too. This give
378 both recursive and non recursive access. The name \fIallow_snoop\fR refers
379 to cache snooping, a technique to use nonrecursive queries to examine
380 the cache contents (for malicious acts). However, nonrecursive queries can
381 also be a valuable debugging tool (when you want to examine the cache
382 contents). In that case use \fIallow_snoop\fR for your administration host.
384 By default only localhost is \fIallow\fRed, the rest is \fIrefuse\fRd.
385 The default is \fIrefuse\fRd, because that is protocol\-friendly. The DNS
386 protocol is not designed to handle dropped packets due to policy, and
387 dropping may result in (possibly excessive) retried queries.
389 The deny_non_local and refuse_non_local settings are for hosts that are
390 only allowed to query for the authoritative local\-data, they are not
391 allowed full recursion but only the static data. With deny_non_local,
392 messages that are disallowed are dropped, with refuse_non_local they
393 receive error code REFUSED.
395 .B chroot: \fI<directory>
396 If chroot is enabled, you should pass the configfile (from the
397 commandline) as a full path from the original root. After the
398 chroot has been performed the now defunct portion of the config
399 file path is removed to be able to reread the config after a reload.
401 All other file paths (working dir, logfile, roothints, and
402 key files) can be specified in several ways:
403 as an absolute path relative to the new root,
404 as a relative path to the working directory, or
405 as an absolute path relative to the original root.
406 In the last case the path is adjusted to remove the unused portion.
408 The pidfile can be either a relative path to the working directory, or
409 an absolute path relative to the original root. It is written just prior
410 to chroot and dropping permissions. This allows the pidfile to be
411 /var/run/unbound.pid and the chroot to be /var/unbound, for example.
413 Additionally, unbound may need to access /dev/random (for entropy)
414 from inside the chroot.
416 If given a chroot is done to the given directory. The default is
417 "/var/unbound". If you give "" no chroot is performed.
419 .B username: \fI<name>
420 If given, after binding the port the user privileges are dropped. Default is
421 "unbound". If you give username: "" no user change is performed.
423 If this user is not capable of binding the
424 port, reloads (by signal HUP) will still retain the opened ports.
425 If you change the port number in the config file, and that new port number
426 requires privileges, then a reload will fail; a restart is needed.
428 .B directory: \fI<directory>
429 Sets the working directory for the program. Default is "/var/unbound".
431 .B logfile: \fI<filename>
432 If "" is given, logging goes to stderr, or nowhere once daemonized.
433 The logfile is appended to, in the following format:
435 [seconds since 1970] unbound[pid:tid]: type: message.
437 If this option is given, the use\-syslog is option is set to "no".
438 The logfile is reopened (for append) when the config file is reread, on
441 .B use\-syslog: \fI<yes or no>
442 Sets unbound to send log messages to the syslogd, using
444 The log facility LOG_DAEMON is used, with identity "unbound".
445 The logfile setting is overridden when use\-syslog is turned on.
446 The default is to log to syslog.
448 .B log\-time\-ascii: \fI<yes or no>
449 Sets logfile lines to use a timestamp in UTC ascii. Default is no, which
450 prints the seconds since 1970 in brackets. No effect if using syslog, in
451 that case syslog formats the timestamp printed into the log files.
453 .B log\-queries: \fI<yes or no>
454 Prints one line per query to the log, with the log timestamp and IP address,
455 name, type and class. Default is no. Note that it takes time to print these
456 lines which makes the server (significantly) slower. Odd (nonprintable)
457 characters in names are printed as '?'.
459 .B pidfile: \fI<filename>
460 The process id is written to the file. Default is "/var/unbound/unbound.pid".
463 kill \-HUP `cat /var/unbound/unbound.pid`
467 kill \-QUIT `cat /var/unbound/unbound.pid`
469 gracefully terminates.
471 .B root\-hints: \fI<filename>
472 Read the root hints from this file. Default is nothing, using builtin hints
473 for the IN class. The file has the format of zone files, with root
474 nameserver names and addresses only. The default may become outdated,
475 when servers change, therefore it is good practice to use a root\-hints file.
477 .B hide\-identity: \fI<yes or no>
478 If enabled id.server and hostname.bind queries are refused.
480 .B identity: \fI<string>
481 Set the identity to report. If set to "", the default, then the hostname
482 of the server is returned.
484 .B hide\-version: \fI<yes or no>
485 If enabled version.server and version.bind queries are refused.
487 .B version: \fI<string>
488 Set the version to report. If set to "", the default, then the package
491 .B target\-fetch\-policy: \fI<"list of numbers">
492 Set the target fetch policy used by unbound to determine if it should fetch
493 nameserver target addresses opportunistically. The policy is described per
496 The number of values determines the maximum dependency depth
497 that unbound will pursue in answering a query.
498 A value of \-1 means to fetch all targets opportunistically for that dependency
499 depth. A value of 0 means to fetch on demand only. A positive value fetches
500 that many targets opportunistically.
502 Enclose the list between quotes ("") and put spaces between numbers.
503 The default is "3 2 1 0 0". Setting all zeroes, "0 0 0 0 0" gives behaviour
504 closer to that of BIND 9, while setting "\-1 \-1 \-1 \-1 \-1" gives behaviour
505 rumoured to be closer to that of BIND 8.
507 .B harden\-short\-bufsize: \fI<yes or no>
508 Very small EDNS buffer sizes from queries are ignored. Default is off, since
509 it is legal protocol wise to send these, and unbound tries to give very
510 small answers to these queries, where possible.
512 .B harden\-large\-queries: \fI<yes or no>
513 Very large queries are ignored. Default is off, since it is legal protocol
514 wise to send these, and could be necessary for operation if TSIG or EDNS
515 payload is very large.
517 .B harden\-glue: \fI<yes or no>
518 Will trust glue only if it is within the servers authority. Default is on.
520 .B harden\-dnssec\-stripped: \fI<yes or no>
521 Require DNSSEC data for trust\-anchored zones, if such data is absent,
522 the zone becomes bogus. If turned off, and no DNSSEC data is received
523 (or the DNSKEY data fails to validate), then the zone is made insecure,
524 this behaves like there is no trust anchor. You could turn this off if
525 you are sometimes behind an intrusive firewall (of some sort) that
526 removes DNSSEC data from packets, or a zone changes from signed to
527 unsigned to badly signed often. If turned off you run the risk of a
528 downgrade attack that disables security for a zone. Default is on.
530 .B harden\-below\-nxdomain: \fI<yes or no>
531 From draft\-vixie\-dnsext\-resimprove, returns nxdomain to queries for a name
532 below another name that is already known to be nxdomain. DNSSEC mandates
533 noerror for empty nonterminals, hence this is possible. Very old software
534 might return nxdomain for empty nonterminals (that usually happen for reverse
535 IP address lookups), and thus may be incompatible with this. To try to avoid
536 this only DNSSEC-secure nxdomains are used, because the old software does not
537 have DNSSEC. Default is off.
539 .B harden\-referral\-path: \fI<yes or no>
540 Harden the referral path by performing additional queries for
541 infrastructure data. Validates the replies if trust anchors are configured
542 and the zones are signed. This enforces DNSSEC validation on nameserver
543 NS sets and the nameserver addresses that are encountered on the referral
545 Default off, because it burdens the authority servers, and it is
546 not RFC standard, and could lead to performance problems because of the
547 extra query load that is generated. Experimental option.
548 If you enable it consider adding more numbers after the target\-fetch\-policy
549 to increase the max depth that is checked to.
551 .B use\-caps\-for\-id: \fI<yes or no>
552 Use 0x20\-encoded random bits in the query to foil spoof attempts.
553 This perturbs the lowercase and uppercase of query names sent to
554 authority servers and checks if the reply still has the correct casing.
556 This feature is an experimental implementation of draft dns\-0x20.
558 .B private\-address: \fI<IP address or subnet>
559 Give IPv4 of IPv6 addresses or classless subnets. These are addresses
560 on your private network, and are not allowed to be returned for public
561 internet names. Any occurence of such addresses are removed from
562 DNS answers. Additionally, the DNSSEC validator may mark the answers
563 bogus. This protects against so\-called DNS Rebinding, where a user browser
564 is turned into a network proxy, allowing remote access through the browser
565 to other parts of your private network. Some names can be allowed to
566 contain your private addresses, by default all the \fBlocal\-data\fR
567 that you configured is allowed to, and you can specify additional
568 names using \fBprivate\-domain\fR. No private addresses are enabled
569 by default. We consider to enable this for the RFC1918 private IP
570 address space by default in later releases. That would enable private
571 addresses for 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 169.254.0.0/16
572 fd00::/8 and fe80::/10, since the RFC standards say these addresses
573 should not be visible on the public internet. Turning on 127.0.0.0/8
574 would hinder many spamblocklists as they use that.
576 .B private\-domain: \fI<domain name>
577 Allow this domain, and all its subdomains to contain private addresses.
578 Give multiple times to allow multiple domain names to contain private
579 addresses. Default is none.
581 .B unwanted\-reply\-threshold: \fI<number>
582 If set, a total number of unwanted replies is kept track of in every thread.
583 When it reaches the threshold, a defensive action is taken and a warning
584 is printed to the log. The defensive action is to clear the rrset and
585 message caches, hopefully flushing away any poison. A value of 10 million
586 is suggested. Default is 0 (turned off).
588 .B do\-not\-query\-address: \fI<IP address>
589 Do not query the given IP address. Can be IP4 or IP6. Append /num to
590 indicate a classless delegation netblock, for example like
591 10.2.3.4/24 or 2001::11/64.
593 .B do\-not\-query\-localhost: \fI<yes or no>
594 If yes, localhost is added to the do\-not\-query\-address entries, both
595 IP6 ::1 and IP4 127.0.0.1/8. If no, then localhost can be used to send
596 queries to. Default is yes.
598 .B prefetch: \fI<yes or no>
599 If yes, message cache elements are prefetched before they expire to
600 keep the cache up to date. Default is no. Turning it on gives about
601 10 percent more traffic and load on the machine, but popular items do
602 not expire from the cache.
604 .B prefetch-key: \fI<yes or no>
605 If yes, fetch the DNSKEYs earlier in the validation process, when a DS
606 record is encountered. This lowers the latency of requests. It does use
607 a little more CPU. Also if the cache is set to 0, it is no use. Default is no.
609 .B rrset-roundrobin: \fI<yes or no>
610 If yes, Unbound rotates RRSet order in response (the random number is taken
611 from the query ID, for speed and thread safety). Default is no.
613 .B minimal-responses: \fI<yes or no>
614 If yes, Unbound doesn't insert authority/additional sections into response
615 messages when those sections are not required. This reduces response
616 size significantly, and may avoid TCP fallback for some responses.
617 This may cause a slight speedup. The default is no, because the DNS
618 protocol RFCs mandate these sections, and the additional content could
619 be of use and save roundtrips for clients.
621 .B module\-config: \fI<"module names">
622 Module configuration, a list of module names separated by spaces, surround
623 the string with quotes (""). The modules can be validator, iterator.
624 Setting this to "iterator" will result in a non\-validating server.
625 Setting this to "validator iterator" will turn on DNSSEC validation.
626 The ordering of the modules is important.
627 You must also set trust\-anchors for validation to be useful.
629 .B trust\-anchor\-file: \fI<filename>
630 File with trusted keys for validation. Both DS and DNSKEY entries can appear
631 in the file. The format of the file is the standard DNS Zone file format.
632 Default is "", or no trust anchor file.
634 .B auto\-trust\-anchor\-file: \fI<filename>
635 File with trust anchor for one zone, which is tracked with RFC5011 probes.
636 The probes are several times per month, thus the machine must be online
637 frequently. The initial file can be one with contents as described in
638 \fBtrust\-anchor\-file\fR. The file is written to when the anchor is updated,
639 so the unbound user must have write permission.
641 .B trust\-anchor: \fI<"Resource Record">
642 A DS or DNSKEY RR for a key to use for validation. Multiple entries can be
643 given to specify multiple trusted keys, in addition to the trust\-anchor\-files.
644 The resource record is entered in the same format as 'dig' or 'drill' prints
645 them, the same format as in the zone file. Has to be on a single line, with
646 "" around it. A TTL can be specified for ease of cut and paste, but is ignored.
647 A class can be specified, but class IN is default.
649 .B trusted\-keys\-file: \fI<filename>
650 File with trusted keys for validation. Specify more than one file
651 with several entries, one file per entry. Like \fBtrust\-anchor\-file\fR
652 but has a different file format. Format is BIND\-9 style format,
653 the trusted\-keys { name flag proto algo "key"; }; clauses are read.
654 It is possible to use wildcards with this statement, the wildcard is
655 expanded on start and on reload.
657 .B dlv\-anchor\-file: \fI<filename>
658 File with trusted keys for DLV (DNSSEC Lookaside Validation). Both DS and
659 DNSKEY entries can be used in the file, in the same format as for
660 \fItrust\-anchor\-file:\fR statements. Only one DLV can be configured, more
661 would be slow. The DLV configured is used as a root trusted DLV, this
662 means that it is a lookaside for the root. Default is "", or no dlv anchor file.
664 .B dlv\-anchor: \fI<"Resource Record">
665 Much like trust\-anchor, this is a DLV anchor with the DS or DNSKEY inline.
667 .B domain\-insecure: \fI<domain name>
668 Sets domain name to be insecure, DNSSEC chain of trust is ignored towards
669 the domain name. So a trust anchor above the domain name can not make the
670 domain secure with a DS record, such a DS record is then ignored.
671 Also keys from DLV are ignored for the domain. Can be given multiple times
672 to specify multiple domains that are treated as if unsigned. If you set
673 trust anchors for the domain they override this setting (and the domain
676 This can be useful if you want to make sure a trust anchor for external
677 lookups does not affect an (unsigned) internal domain. A DS record
678 externally can create validation failures for that internal domain.
680 .B val\-override\-date: \fI<rrsig\-style date spec>
681 Default is "" or "0", which disables this debugging feature. If enabled by
682 giving a RRSIG style date, that date is used for verifying RRSIG inception
683 and expiration dates, instead of the current date. Do not set this unless
684 you are debugging signature inception and expiration. The value \-1 ignores
685 the date altogether, useful for some special applications.
687 .B val\-sig\-skew\-min: \fI<seconds>
688 Minimum number of seconds of clock skew to apply to validated signatures.
689 A value of 10% of the signature lifetime (expiration \- inception) is
690 used, capped by this setting. Default is 3600 (1 hour) which allows for
691 daylight savings differences. Lower this value for more strict checking
692 of short lived signatures.
694 .B val\-sig\-skew\-max: \fI<seconds>
695 Maximum number of seconds of clock skew to apply to validated signatures.
696 A value of 10% of the signature lifetime (expiration \- inception)
697 is used, capped by this setting. Default is 86400 (24 hours) which
698 allows for timezone setting problems in stable domains. Setting both
699 min and max very low disables the clock skew allowances. Setting both
700 min and max very high makes the validator check the signature timestamps
703 .B val\-bogus\-ttl: \fI<number>
704 The time to live for bogus data. This is data that has failed validation;
705 due to invalid signatures or other checks. The TTL from that data cannot be
706 trusted, and this value is used instead. The value is in seconds, default 60.
707 The time interval prevents repeated revalidation of bogus data.
709 .B val\-clean\-additional: \fI<yes or no>
710 Instruct the validator to remove data from the additional section of secure
711 messages that are not signed properly. Messages that are insecure, bogus,
712 indeterminate or unchecked are not affected. Default is yes. Use this setting
713 to protect the users that rely on this validator for authentication from
714 protentially bad data in the additional section.
716 .B val\-log\-level: \fI<number>
717 Have the validator print validation failures to the log. Regardless of
718 the verbosity setting. Default is 0, off. At 1, for every user query
719 that fails a line is printed to the logs. This way you can monitor what
720 happens with validation. Use a diagnosis tool, such as dig or drill,
721 to find out why validation is failing for these queries. At 2, not only
722 the query that failed is printed but also the reason why unbound thought
723 it was wrong and which server sent the faulty data.
725 .B val\-permissive\-mode: \fI<yes or no>
726 Instruct the validator to mark bogus messages as indeterminate. The security
727 checks are performed, but if the result is bogus (failed security), the
728 reply is not withheld from the client with SERVFAIL as usual. The client
729 receives the bogus data. For messages that are found to be secure the AD bit
730 is set in replies. Also logging is performed as for full validation.
731 The default value is "no".
733 .B ignore\-cd\-flag: \fI<yes or no>
734 Instruct unbound to ignore the CD flag from clients and refuse to
735 return bogus answers to them. Thus, the CD (Checking Disabled) flag
736 does not disable checking any more. This is useful if legacy (w2008)
737 servers that set the CD flag but cannot validate DNSSEC themselves are
738 the clients, and then unbound provides them with DNSSEC protection.
739 The default value is "no".
741 .B val\-nsec3\-keysize\-iterations: \fI<"list of values">
742 List of keysize and iteration count values, separated by spaces, surrounded
743 by quotes. Default is "1024 150 2048 500 4096 2500". This determines the
744 maximum allowed NSEC3 iteration count before a message is simply marked
745 insecure instead of performing the many hashing iterations. The list must
746 be in ascending order and have at least one entry. If you set it to
747 "1024 65535" there is no restriction to NSEC3 iteration values.
748 This table must be kept short; a very long list could cause slower operation.
750 .B add\-holddown: \fI<seconds>
751 Instruct the \fBauto\-trust\-anchor\-file\fR probe mechanism for RFC5011
752 autotrust updates to add new trust anchors only after they have been
753 visible for this time. Default is 30 days as per the RFC.
755 .B del\-holddown: \fI<seconds>
756 Instruct the \fBauto\-trust\-anchor\-file\fR probe mechanism for RFC5011
757 autotrust updates to remove revoked trust anchors after they have been
758 kept in the revoked list for this long. Default is 30 days as per
761 .B keep\-missing: \fI<seconds>
762 Instruct the \fBauto\-trust\-anchor\-file\fR probe mechanism for RFC5011
763 autotrust updates to remove missing trust anchors after they have been
764 unseen for this long. This cleans up the state file if the target zone
765 does not perform trust anchor revocation, so this makes the auto probe
766 mechanism work with zones that perform regular (non\-5011) rollovers.
767 The default is 366 days. The value 0 does not remove missing anchors,
770 .B key\-cache\-size: \fI<number>
771 Number of bytes size of the key cache. Default is 4 megabytes.
772 A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
773 or gigabytes (1024*1024 bytes in a megabyte).
775 .B key\-cache\-slabs: \fI<number>
776 Number of slabs in the key cache. Slabs reduce lock contention by threads.
777 Must be set to a power of 2. Setting (close) to the number of cpus is a
780 .B neg\-cache\-size: \fI<number>
781 Number of bytes size of the aggressive negative cache. Default is 1 megabyte.
782 A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
783 or gigabytes (1024*1024 bytes in a megabyte).
785 .B unblock\-lan\-zones: \fI<yesno>
786 Default is disabled. If enabled, then for private address space,
787 the reverse lookups are no longer filtered. This allows unbound when
788 running as dns service on a host where it provides service for that host,
789 to put out all of the queries for the 'lan' upstream. When enabled,
790 only localhost, 127.0.0.1 reverse and ::1 reverse zones are configured
791 with default local zones. Disable the option when unbound is running
792 as a (DHCP-) DNS network resolver for a group of machines, where such
793 lookups should be filtered (RFC compliance), this also stops potential
794 data leakage about the local network to the upstream DNS servers.
796 .B local\-zone: \fI<zone> <type>
797 Configure a local zone. The type determines the answer to give if
798 there is no match from local\-data. The types are deny, refuse, static,
799 transparent, redirect, nodefault, typetransparent, inform, and are explained
800 below. After that the default settings are listed. Use local\-data: to
801 enter data into the local zone. Answers for local zones are authoritative
802 DNS answers. By default the zones are class IN.
804 If you need more complicated authoritative data, with referrals, wildcards,
805 CNAME/DNAME support, or DNSSEC authoritative service, setup a stub\-zone for
806 it as detailed in the stub zone section below.
809 Do not send an answer, drop the query.
810 If there is a match from local data, the query is answered.
813 Send an error message reply, with rcode REFUSED.
814 If there is a match from local data, the query is answered.
817 If there is a match from local data, the query is answered.
818 Otherwise, the query is answered with nodata or nxdomain.
819 For a negative answer a SOA is included in the answer if present
820 as local\-data for the zone apex domain.
822 \h'5'\fItransparent\fR
823 If there is a match from local data, the query is answered.
824 Otherwise if the query has a different name, the query is resolved normally.
825 If the query is for a name given in localdata but no such type of data is
826 given in localdata, then a noerror nodata answer is returned.
827 If no local\-zone is given local\-data causes a transparent zone
828 to be created by default.
830 \h'5'\fItypetransparent\fR
831 If there is a match from local data, the query is answered. If the query
832 is for a different name, or for the same name but for a different type,
833 the query is resolved normally. So, similar to transparent but types
834 that are not listed in local data are resolved normally, so if an A record
835 is in the local data that does not cause a nodata reply for AAAA queries.
838 The query is answered from the local data for the zone name.
839 There may be no local data beneath the zone name.
840 This answers queries for the zone, and all subdomains of the zone
841 with the local data for the zone.
842 It can be used to redirect a domain to return a different address record
843 to the end user, with
844 local\-zone: "example.com." redirect and
845 local\-data: "example.com. A 127.0.0.1"
846 queries for www.example.com and www.foo.example.com are redirected, so
847 that users with web browsers cannot access sites with suffix example.com.
850 The query is answered normally. The client IP address (@portnumber)
851 is printed to the logfile. The log message is: timestamp, unbound-pid,
852 info: zonename inform IP@port queryname type class. This option can be
853 used for normal resolution, but machines looking up infected names are
854 logged, eg. to run antivirus on them.
857 Used to turn off default contents for AS112 zones. The other types
858 also turn off default contents for the zone. The 'nodefault' option
859 has no other effect than turning off default contents for the
862 The default zones are localhost, reverse 127.0.0.1 and ::1, and the AS112
863 zones. The AS112 zones are reverse DNS zones for private use and reserved
864 IP addresses for which the servers on the internet cannot provide correct
865 answers. They are configured by default to give nxdomain (no reverse
866 information) answers. The defaults can be turned off by specifying your
867 own local\-zone of that name, or using the 'nodefault' type. Below is a
868 list of the default zone contents.
871 The IP4 and IP6 localhost information is given. NS and SOA records are provided
872 for completeness and to satisfy some DNS update tools. Default content:
874 local\-zone: "localhost." static
875 local\-data: "localhost. 10800 IN NS localhost."
876 local\-data: "localhost. 10800 IN
877 SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
878 local\-data: "localhost. 10800 IN A 127.0.0.1"
879 local\-data: "localhost. 10800 IN AAAA ::1"
882 \h'5'\fIreverse IPv4 loopback\fR
885 local\-zone: "127.in\-addr.arpa." static
886 local\-data: "127.in\-addr.arpa. 10800 IN NS localhost."
887 local\-data: "127.in\-addr.arpa. 10800 IN
888 SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
889 local\-data: "1.0.0.127.in\-addr.arpa. 10800 IN
893 \h'5'\fIreverse IPv6 loopback\fR
896 local\-zone: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
897 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." static
898 local\-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
899 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
901 local\-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
902 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
903 SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
904 local\-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
905 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
909 \h'5'\fIreverse RFC1918 local use zones\fR
910 Reverse data for zones 10.in\-addr.arpa, 16.172.in\-addr.arpa to
911 31.172.in\-addr.arpa, 168.192.in\-addr.arpa.
912 The \fBlocal\-zone:\fR is set static and as \fBlocal\-data:\fR SOA and NS
913 records are provided.
915 \h'5'\fIreverse RFC3330 IP4 this, link\-local, testnet and broadcast\fR
916 Reverse data for zones 0.in\-addr.arpa, 254.169.in\-addr.arpa,
917 2.0.192.in\-addr.arpa (TEST NET 1), 100.51.198.in\-addr.arpa (TEST NET 2),
918 113.0.203.in\-addr.arpa (TEST NET 3), 255.255.255.255.in\-addr.arpa.
919 And from 64.100.in\-addr.arpa to 127.100.in\-addr.arpa (Shared Address Space).
921 \h'5'\fIreverse RFC4291 IP6 unspecified\fR
922 Reverse data for zone
924 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
925 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.
928 \h'5'\fIreverse RFC4193 IPv6 Locally Assigned Local Addresses\fR
929 Reverse data for zone D.F.ip6.arpa.
931 \h'5'\fIreverse RFC4291 IPv6 Link Local Addresses\fR
932 Reverse data for zones 8.E.F.ip6.arpa to B.E.F.ip6.arpa.
934 \h'5'\fIreverse IPv6 Example Prefix\fR
935 Reverse data for zone 8.B.D.0.1.0.0.2.ip6.arpa. This zone is used for
936 tutorials and examples. You can remove the block on this zone with:
938 local\-zone: 8.B.D.0.1.0.0.2.ip6.arpa. nodefault
940 You can also selectively unblock a part of the zone by making that part
941 transparent with a local\-zone statement.
942 This also works with the other default zones.
943 .\" End of local-zone listing.
945 .B local\-data: \fI"<resource record string>"
946 Configure local data, which is served in reply to queries for it.
947 The query has to match exactly unless you configure the local\-zone as
948 redirect. If not matched exactly, the local\-zone type determines
949 further processing. If local\-data is configured that is not a subdomain of
950 a local\-zone, a transparent local\-zone is configured.
951 For record types such as TXT, use single quotes, as in
952 local\-data: 'example. TXT "text"'.
954 If you need more complicated authoritative data, with referrals, wildcards,
955 CNAME/DNAME support, or DNSSEC authoritative service, setup a stub\-zone for
956 it as detailed in the stub zone section below.
958 .B local\-data\-ptr: \fI"IPaddr name"
959 Configure local data shorthand for a PTR record with the reversed IPv4 or
960 IPv6 address and the host name. For example "192.0.2.4 www.example.com".
961 TTL can be inserted like this: "2001:DB8::4 7200 www.example.com"
962 .SS "Remote Control Options"
965 clause are the declarations for the remote control facility. If this is
966 enabled, the \fIunbound\-control\fR(8) utility can be used to send
967 commands to the running unbound server. The server uses these clauses
968 to setup SSLv3 / TLSv1 security for the connection. The
969 \fIunbound\-control\fR(8) utility also reads the \fBremote\-control\fR
970 section for options. To setup the correct self\-signed certificates use the
971 \fIunbound\-control\-setup\fR(8) utility.
973 .B control\-enable: \fI<yes or no>
974 The option is used to enable remote control, default is "no".
975 If turned off, the server does not listen for control commands.
977 .B control\-interface: \fI<ip address or path>
978 Give IPv4 or IPv6 addresses or local socket path to listen on for
980 By default localhost (127.0.0.1 and ::1) is listened to.
981 Use 0.0.0.0 and ::0 to listen to all interfaces.
982 If you change this and permissions have been dropped, you must restart
983 the server for the change to take effect.
985 .B control\-port: \fI<port number>
986 The port number to listen on for IPv4 or IPv6 control interfaces,
988 If you change this and permissions have been dropped, you must restart
989 the server for the change to take effect.
991 .B control\-use\-cert: \fI<yes or no>
992 Whether to require certificate authentication of control connections.
993 The default is "yes".
994 This should not be changed unless there are other mechanisms in place
995 to prevent untrusted users from accessing the remote control
998 .B server\-key\-file: \fI<private key file>
999 Path to the server private key, by default unbound_server.key.
1000 This file is generated by the \fIunbound\-control\-setup\fR utility.
1001 This file is used by the unbound server, but not by \fIunbound\-control\fR.
1003 .B server\-cert\-file: \fI<certificate file.pem>
1004 Path to the server self signed certificate, by default unbound_server.pem.
1005 This file is generated by the \fIunbound\-control\-setup\fR utility.
1006 This file is used by the unbound server, and also by \fIunbound\-control\fR.
1008 .B control\-key\-file: \fI<private key file>
1009 Path to the control client private key, by default unbound_control.key.
1010 This file is generated by the \fIunbound\-control\-setup\fR utility.
1011 This file is used by \fIunbound\-control\fR.
1013 .B control\-cert\-file: \fI<certificate file.pem>
1014 Path to the control client certificate, by default unbound_control.pem.
1015 This certificate has to be signed with the server certificate.
1016 This file is generated by the \fIunbound\-control\-setup\fR utility.
1017 This file is used by \fIunbound\-control\fR.
1018 .SS "Stub Zone Options"
1020 There may be multiple
1022 clauses. Each with a name: and zero or more hostnames or IP addresses.
1023 For the stub zone this list of nameservers is used. Class IN is assumed.
1024 The servers should be authority servers, not recursors; unbound performs
1025 the recursive processing itself for stub zones.
1027 The stub zone can be used to configure authoritative data to be used
1028 by the resolver that cannot be accessed using the public internet servers.
1029 This is useful for company\-local data or private zones. Setup an
1030 authoritative server on a different host (or different port). Enter a config
1031 entry for unbound with
1033 <ip address of host[@port]>.
1034 The unbound resolver can then access the data, without referring to the
1035 public internet for it.
1037 This setup allows DNSSEC signed zones to be served by that
1038 authoritative server, in which case a trusted key entry with the public key
1039 can be put in config, so that unbound can validate the data and set the AD
1040 bit on replies for the private zone (authoritative servers do not set the
1041 AD bit). This setup makes unbound capable of answering queries for the
1042 private zone, and can even set the AD bit ('authentic'), but the AA
1043 ('authoritative') bit is not set on these replies.
1045 .B name: \fI<domain name>
1046 Name of the stub zone.
1048 .B stub\-host: \fI<domain name>
1049 Name of stub zone nameserver. Is itself resolved before it is used.
1051 .B stub\-addr: \fI<IP address>
1052 IP address of stub zone nameserver. Can be IP 4 or IP 6.
1053 To use a nondefault port for DNS communication append '@' with the port number.
1055 .B stub\-prime: \fI<yes or no>
1056 This option is by default off. If enabled it performs NS set priming,
1057 which is similar to root hints, where it starts using the list of nameservers
1058 currently published by the zone. Thus, if the hint list is slightly outdated,
1059 the resolver picks up a correct list online.
1061 .B stub\-first: \fI<yes or no>
1062 If enabled, a query is attempted without the stub clause if it fails.
1063 The data could not be retrieved and would have caused SERVFAIL because
1064 the servers are unreachable, instead it is tried without this clause.
1066 .SS "Forward Zone Options"
1068 There may be multiple
1070 clauses. Each with a \fBname:\fR and zero or more hostnames or IP
1071 addresses. For the forward zone this list of nameservers is used to
1072 forward the queries to. The servers listed as \fBforward\-host:\fR and
1073 \fBforward\-addr:\fR have to handle further recursion for the query. Thus,
1074 those servers are not authority servers, but are (just like unbound is)
1075 recursive servers too; unbound does not perform recursion itself for the
1076 forward zone, it lets the remote server do it. Class IN is assumed.
1077 A forward\-zone entry with name "." and a forward\-addr target will
1078 forward all queries to that other server (unless it can answer from
1081 .B name: \fI<domain name>
1082 Name of the forward zone.
1084 .B forward\-host: \fI<domain name>
1085 Name of server to forward to. Is itself resolved before it is used.
1087 .B forward\-addr: \fI<IP address>
1088 IP address of server to forward to. Can be IP 4 or IP 6.
1089 To use a nondefault port for DNS communication append '@' with the port number.
1091 .B forward\-first: \fI<yes or no>
1092 If enabled, a query is attempted without the forward clause if it fails.
1093 The data could not be retrieved and would have caused SERVFAIL because
1094 the servers are unreachable, instead it is tried without this clause.
1096 .SS "Python Module Options"
1100 clause gives the settings for the \fIpython\fR(1) script module. This module
1101 acts like the iterator and validator modules do, on queries and answers.
1102 To enable the script module it has to be compiled into the daemon,
1103 and the word "python" has to be put in the \fBmodule\-config:\fR option
1104 (usually first, or between the validator and iterator).
1106 .B python\-script: \fI<python file>\fR
1107 The script file to load.
1108 .SS "DNS64 Module Options"
1110 The dns64 module must be configured in the \fBmodule\-config:\fR "dns64
1111 validator iterator" directive and be compiled into the daemon to be
1112 enabled. These settings go in the \fBserver:\fR section.
1114 .B dns64\-prefix: \fI<IPv6 prefix>\fR
1115 This sets the DNS64 prefix to use to synthesize AAAA records with.
1116 It must be /96 or shorter. The default prefix is 64:ff9b::/96.
1118 .B dns64\-synthall: \fI<yes or no>\fR
1119 Debug option, default no. If enabled, synthesize all AAAA records
1120 despite the presence of actual AAAA records.
1121 .SH "MEMORY CONTROL EXAMPLE"
1122 In the example config settings below memory usage is reduced. Some service
1123 levels are lower, notable very large data and a high TCP load are no longer
1124 supported. Very large data and high TCP loads are exceptional for the DNS.
1125 DNSSEC validation is enabled, just add trust anchors.
1126 If you do not have to worry about programs using more than 3 Mb of memory,
1127 the below example is not for you. Use the defaults to receive full service,
1128 which on BSD\-32bit tops out at 30\-40 Mb after heavy usage.
1131 # example settings that reduce memory usage
1134 outgoing\-num\-tcp: 1 # this limits TCP service, uses less buffers.
1135 incoming\-num\-tcp: 1
1136 outgoing\-range: 60 # uses less memory, but less performance.
1137 msg\-buffer\-size: 8192 # note this limits service, 'no huge stuff'.
1138 msg\-cache\-size: 100k
1139 msg\-cache\-slabs: 1
1140 rrset\-cache\-size: 100k
1141 rrset\-cache\-slabs: 1
1142 infra\-cache\-numhosts: 200
1143 infra\-cache\-slabs: 1
1144 key\-cache\-size: 100k
1145 key\-cache\-slabs: 1
1146 neg\-cache\-size: 10k
1147 num\-queries\-per\-thread: 30
1148 target\-fetch\-policy: "2 1 0 0 0 0"
1149 harden\-large\-queries: "yes"
1150 harden\-short\-bufsize: "yes"
1155 default unbound working directory.
1162 .I /var/unbound/unbound.conf
1163 unbound configuration file.
1165 .I /var/unbound/unbound.pid
1166 default unbound pidfile with process ID of the running daemon.
1169 unbound log file. default is to log to
1173 \fIunbound\-checkconf\fR(8).
1176 was written by NLnet Labs. Please see CREDITS file
1177 in the distribution for further details.
projects / FreeBSD / releng / 10.2.git / blob