1 .TH "unbound.conf" "5" "Dec 8, 2014" "NLnet Labs" "unbound 1.5.1"
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 do\-ip4: \fI<yes or no>
305 Enable or disable whether ip4 queries are answered or issued. Default is yes.
307 .B do\-ip6: \fI<yes or no>
308 Enable or disable whether ip6 queries are answered or issued. Default is yes.
309 If disabled, queries are not answered on IPv6, and queries are not sent on
310 IPv6 to the internet nameservers. With this option you can disable the
311 ipv6 transport for sending DNS traffic, it does not impact the contents of
312 the DNS traffic, which may have ip4 and ip6 addresses in it.
314 .B do\-udp: \fI<yes or no>
315 Enable or disable whether UDP queries are answered or issued. Default is yes.
317 .B do\-tcp: \fI<yes or no>
318 Enable or disable whether TCP queries are answered or issued. Default is yes.
320 .B tcp\-upstream: \fI<yes or no>
321 Enable or disable whether the upstream queries use TCP only for transport.
322 Default is no. Useful in tunneling scenarios.
324 .B ssl\-upstream: \fI<yes or no>
325 Enabled or disable whether the upstream queries use SSL only for transport.
326 Default is no. Useful in tunneling scenarios. The SSL contains plain DNS in
327 TCP wireformat. The other server must support this (see \fBssl\-service\-key\fR).
329 .B ssl\-service-key: \fI<file>
330 If enabled, the server provider SSL service on its TCP sockets. The clients
331 have to use ssl\-upstream: yes. The file is the private key for the TLS
332 session. The public certificate is in the ssl\-service\-pem file. Default
333 is "", turned off. Requires a restart (a reload is not enough) if changed,
334 because the private key is read while root permissions are held and before
335 chroot (if any). Normal DNS TCP service is not provided and gives errors,
336 this service is best run with a different \fBport:\fR config or \fI@port\fR
337 suffixes in the \fBinterface\fR config.
339 .B ssl\-service\-pem: \fI<file>
340 The public key certificate pem file for the ssl service. Default is "",
343 .B ssl\-port: \fI<number>
344 The port number on which to provide TCP SSL service, default 443, only
345 interfaces configured with that port number as @number get the SSL service.
347 .B do\-daemonize: \fI<yes or no>
348 Enable or disable whether the unbound server forks into the background as
349 a daemon. Default is yes.
351 .B access\-control: \fI<IP netblock> <action>
352 The netblock is given as an IP4 or IP6 address with /size appended for a
353 classless network block. The action can be \fIdeny\fR, \fIrefuse\fR,
354 \fIallow\fR, \fIallow_snoop\fR, \fIdeny_non_local\fR or \fIrefuse_non_local\fR.
356 The action \fIdeny\fR stops queries from hosts from that netblock.
358 The action \fIrefuse\fR stops queries too, but sends a DNS rcode REFUSED
361 The action \fIallow\fR gives access to clients from that netblock.
362 It gives only access for recursion clients (which is
363 what almost all clients need). Nonrecursive queries are refused.
365 The \fIallow\fR action does allow nonrecursive queries to access the
366 local\-data that is configured. The reason is that this does not involve
367 the unbound server recursive lookup algorithm, and static data is served
368 in the reply. This supports normal operations where nonrecursive queries
369 are made for the authoritative data. For nonrecursive queries any replies
370 from the dynamic cache are refused.
372 The action \fIallow_snoop\fR gives nonrecursive access too. This give
373 both recursive and non recursive access. The name \fIallow_snoop\fR refers
374 to cache snooping, a technique to use nonrecursive queries to examine
375 the cache contents (for malicious acts). However, nonrecursive queries can
376 also be a valuable debugging tool (when you want to examine the cache
377 contents). In that case use \fIallow_snoop\fR for your administration host.
379 By default only localhost is \fIallow\fRed, the rest is \fIrefuse\fRd.
380 The default is \fIrefuse\fRd, because that is protocol\-friendly. The DNS
381 protocol is not designed to handle dropped packets due to policy, and
382 dropping may result in (possibly excessive) retried queries.
384 The deny_non_local and refuse_non_local settings are for hosts that are
385 only allowed to query for the authoritative local\-data, they are not
386 allowed full recursion but only the static data. With deny_non_local,
387 messages that are disallowed are dropped, with refuse_non_local they
388 receive error code REFUSED.
390 .B chroot: \fI<directory>
391 If chroot is enabled, you should pass the configfile (from the
392 commandline) as a full path from the original root. After the
393 chroot has been performed the now defunct portion of the config
394 file path is removed to be able to reread the config after a reload.
396 All other file paths (working dir, logfile, roothints, and
397 key files) can be specified in several ways:
398 as an absolute path relative to the new root,
399 as a relative path to the working directory, or
400 as an absolute path relative to the original root.
401 In the last case the path is adjusted to remove the unused portion.
403 The pidfile can be either a relative path to the working directory, or
404 an absolute path relative to the original root. It is written just prior
405 to chroot and dropping permissions. This allows the pidfile to be
406 /var/run/unbound.pid and the chroot to be /var/unbound, for example.
408 Additionally, unbound may need to access /dev/random (for entropy)
409 from inside the chroot.
411 If given a chroot is done to the given directory. The default is
412 "/var/unbound". If you give "" no chroot is performed.
414 .B username: \fI<name>
415 If given, after binding the port the user privileges are dropped. Default is
416 "unbound". If you give username: "" no user change is performed.
418 If this user is not capable of binding the
419 port, reloads (by signal HUP) will still retain the opened ports.
420 If you change the port number in the config file, and that new port number
421 requires privileges, then a reload will fail; a restart is needed.
423 .B directory: \fI<directory>
424 Sets the working directory for the program. Default is "/var/unbound".
426 .B logfile: \fI<filename>
427 If "" is given, logging goes to stderr, or nowhere once daemonized.
428 The logfile is appended to, in the following format:
430 [seconds since 1970] unbound[pid:tid]: type: message.
432 If this option is given, the use\-syslog is option is set to "no".
433 The logfile is reopened (for append) when the config file is reread, on
436 .B use\-syslog: \fI<yes or no>
437 Sets unbound to send log messages to the syslogd, using
439 The log facility LOG_DAEMON is used, with identity "unbound".
440 The logfile setting is overridden when use\-syslog is turned on.
441 The default is to log to syslog.
443 .B log\-time\-ascii: \fI<yes or no>
444 Sets logfile lines to use a timestamp in UTC ascii. Default is no, which
445 prints the seconds since 1970 in brackets. No effect if using syslog, in
446 that case syslog formats the timestamp printed into the log files.
448 .B log\-queries: \fI<yes or no>
449 Prints one line per query to the log, with the log timestamp and IP address,
450 name, type and class. Default is no. Note that it takes time to print these
451 lines which makes the server (significantly) slower. Odd (nonprintable)
452 characters in names are printed as '?'.
454 .B pidfile: \fI<filename>
455 The process id is written to the file. Default is "/var/unbound/unbound.pid".
458 kill \-HUP `cat /var/unbound/unbound.pid`
462 kill \-QUIT `cat /var/unbound/unbound.pid`
464 gracefully terminates.
466 .B root\-hints: \fI<filename>
467 Read the root hints from this file. Default is nothing, using builtin hints
468 for the IN class. The file has the format of zone files, with root
469 nameserver names and addresses only. The default may become outdated,
470 when servers change, therefore it is good practice to use a root\-hints file.
472 .B hide\-identity: \fI<yes or no>
473 If enabled id.server and hostname.bind queries are refused.
475 .B identity: \fI<string>
476 Set the identity to report. If set to "", the default, then the hostname
477 of the server is returned.
479 .B hide\-version: \fI<yes or no>
480 If enabled version.server and version.bind queries are refused.
482 .B version: \fI<string>
483 Set the version to report. If set to "", the default, then the package
486 .B target\-fetch\-policy: \fI<"list of numbers">
487 Set the target fetch policy used by unbound to determine if it should fetch
488 nameserver target addresses opportunistically. The policy is described per
491 The number of values determines the maximum dependency depth
492 that unbound will pursue in answering a query.
493 A value of \-1 means to fetch all targets opportunistically for that dependency
494 depth. A value of 0 means to fetch on demand only. A positive value fetches
495 that many targets opportunistically.
497 Enclose the list between quotes ("") and put spaces between numbers.
498 The default is "3 2 1 0 0". Setting all zeroes, "0 0 0 0 0" gives behaviour
499 closer to that of BIND 9, while setting "\-1 \-1 \-1 \-1 \-1" gives behaviour
500 rumoured to be closer to that of BIND 8.
502 .B harden\-short\-bufsize: \fI<yes or no>
503 Very small EDNS buffer sizes from queries are ignored. Default is off, since
504 it is legal protocol wise to send these, and unbound tries to give very
505 small answers to these queries, where possible.
507 .B harden\-large\-queries: \fI<yes or no>
508 Very large queries are ignored. Default is off, since it is legal protocol
509 wise to send these, and could be necessary for operation if TSIG or EDNS
510 payload is very large.
512 .B harden\-glue: \fI<yes or no>
513 Will trust glue only if it is within the servers authority. Default is on.
515 .B harden\-dnssec\-stripped: \fI<yes or no>
516 Require DNSSEC data for trust\-anchored zones, if such data is absent,
517 the zone becomes bogus. If turned off, and no DNSSEC data is received
518 (or the DNSKEY data fails to validate), then the zone is made insecure,
519 this behaves like there is no trust anchor. You could turn this off if
520 you are sometimes behind an intrusive firewall (of some sort) that
521 removes DNSSEC data from packets, or a zone changes from signed to
522 unsigned to badly signed often. If turned off you run the risk of a
523 downgrade attack that disables security for a zone. Default is on.
525 .B harden\-below\-nxdomain: \fI<yes or no>
526 From draft\-vixie\-dnsext\-resimprove, returns nxdomain to queries for a name
527 below another name that is already known to be nxdomain. DNSSEC mandates
528 noerror for empty nonterminals, hence this is possible. Very old software
529 might return nxdomain for empty nonterminals (that usually happen for reverse
530 IP address lookups), and thus may be incompatible with this. To try to avoid
531 this only DNSSEC-secure nxdomains are used, because the old software does not
532 have DNSSEC. Default is off.
534 .B harden\-referral\-path: \fI<yes or no>
535 Harden the referral path by performing additional queries for
536 infrastructure data. Validates the replies if trust anchors are configured
537 and the zones are signed. This enforces DNSSEC validation on nameserver
538 NS sets and the nameserver addresses that are encountered on the referral
540 Default off, because it burdens the authority servers, and it is
541 not RFC standard, and could lead to performance problems because of the
542 extra query load that is generated. Experimental option.
543 If you enable it consider adding more numbers after the target\-fetch\-policy
544 to increase the max depth that is checked to.
546 .B use\-caps\-for\-id: \fI<yes or no>
547 Use 0x20\-encoded random bits in the query to foil spoof attempts.
548 This perturbs the lowercase and uppercase of query names sent to
549 authority servers and checks if the reply still has the correct casing.
551 This feature is an experimental implementation of draft dns\-0x20.
553 .B private\-address: \fI<IP address or subnet>
554 Give IPv4 of IPv6 addresses or classless subnets. These are addresses
555 on your private network, and are not allowed to be returned for public
556 internet names. Any occurence of such addresses are removed from
557 DNS answers. Additionally, the DNSSEC validator may mark the answers
558 bogus. This protects against so\-called DNS Rebinding, where a user browser
559 is turned into a network proxy, allowing remote access through the browser
560 to other parts of your private network. Some names can be allowed to
561 contain your private addresses, by default all the \fBlocal\-data\fR
562 that you configured is allowed to, and you can specify additional
563 names using \fBprivate\-domain\fR. No private addresses are enabled
564 by default. We consider to enable this for the RFC1918 private IP
565 address space by default in later releases. That would enable private
566 addresses for 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 169.254.0.0/16
567 fd00::/8 and fe80::/10, since the RFC standards say these addresses
568 should not be visible on the public internet. Turning on 127.0.0.0/8
569 would hinder many spamblocklists as they use that.
571 .B private\-domain: \fI<domain name>
572 Allow this domain, and all its subdomains to contain private addresses.
573 Give multiple times to allow multiple domain names to contain private
574 addresses. Default is none.
576 .B unwanted\-reply\-threshold: \fI<number>
577 If set, a total number of unwanted replies is kept track of in every thread.
578 When it reaches the threshold, a defensive action is taken and a warning
579 is printed to the log. The defensive action is to clear the rrset and
580 message caches, hopefully flushing away any poison. A value of 10 million
581 is suggested. Default is 0 (turned off).
583 .B do\-not\-query\-address: \fI<IP address>
584 Do not query the given IP address. Can be IP4 or IP6. Append /num to
585 indicate a classless delegation netblock, for example like
586 10.2.3.4/24 or 2001::11/64.
588 .B do\-not\-query\-localhost: \fI<yes or no>
589 If yes, localhost is added to the do\-not\-query\-address entries, both
590 IP6 ::1 and IP4 127.0.0.1/8. If no, then localhost can be used to send
591 queries to. Default is yes.
593 .B prefetch: \fI<yes or no>
594 If yes, message cache elements are prefetched before they expire to
595 keep the cache up to date. Default is no. Turning it on gives about
596 10 percent more traffic and load on the machine, but popular items do
597 not expire from the cache.
599 .B prefetch-key: \fI<yes or no>
600 If yes, fetch the DNSKEYs earlier in the validation process, when a DS
601 record is encountered. This lowers the latency of requests. It does use
602 a little more CPU. Also if the cache is set to 0, it is no use. Default is no.
604 .B rrset-roundrobin: \fI<yes or no>
605 If yes, Unbound rotates RRSet order in response (the random number is taken
606 from the query ID, for speed and thread safety). Default is no.
608 .B minimal-responses: \fI<yes or no>
609 If yes, Unbound doesn't insert authority/additional sections into response
610 messages when those sections are not required. This reduces response
611 size significantly, and may avoid TCP fallback for some responses.
612 This may cause a slight speedup. The default is no, because the DNS
613 protocol RFCs mandate these sections, and the additional content could
614 be of use and save roundtrips for clients.
616 .B module\-config: \fI<"module names">
617 Module configuration, a list of module names separated by spaces, surround
618 the string with quotes (""). The modules can be validator, iterator.
619 Setting this to "iterator" will result in a non\-validating server.
620 Setting this to "validator iterator" will turn on DNSSEC validation.
621 The ordering of the modules is important.
622 You must also set trust\-anchors for validation to be useful.
624 .B trust\-anchor\-file: \fI<filename>
625 File with trusted keys for validation. Both DS and DNSKEY entries can appear
626 in the file. The format of the file is the standard DNS Zone file format.
627 Default is "", or no trust anchor file.
629 .B auto\-trust\-anchor\-file: \fI<filename>
630 File with trust anchor for one zone, which is tracked with RFC5011 probes.
631 The probes are several times per month, thus the machine must be online
632 frequently. The initial file can be one with contents as described in
633 \fBtrust\-anchor\-file\fR. The file is written to when the anchor is updated,
634 so the unbound user must have write permission.
636 .B trust\-anchor: \fI<"Resource Record">
637 A DS or DNSKEY RR for a key to use for validation. Multiple entries can be
638 given to specify multiple trusted keys, in addition to the trust\-anchor\-files.
639 The resource record is entered in the same format as 'dig' or 'drill' prints
640 them, the same format as in the zone file. Has to be on a single line, with
641 "" around it. A TTL can be specified for ease of cut and paste, but is ignored.
642 A class can be specified, but class IN is default.
644 .B trusted\-keys\-file: \fI<filename>
645 File with trusted keys for validation. Specify more than one file
646 with several entries, one file per entry. Like \fBtrust\-anchor\-file\fR
647 but has a different file format. Format is BIND\-9 style format,
648 the trusted\-keys { name flag proto algo "key"; }; clauses are read.
649 It is possible to use wildcards with this statement, the wildcard is
650 expanded on start and on reload.
652 .B dlv\-anchor\-file: \fI<filename>
653 File with trusted keys for DLV (DNSSEC Lookaside Validation). Both DS and
654 DNSKEY entries can be used in the file, in the same format as for
655 \fItrust\-anchor\-file:\fR statements. Only one DLV can be configured, more
656 would be slow. The DLV configured is used as a root trusted DLV, this
657 means that it is a lookaside for the root. Default is "", or no dlv anchor file.
659 .B dlv\-anchor: \fI<"Resource Record">
660 Much like trust\-anchor, this is a DLV anchor with the DS or DNSKEY inline.
662 .B domain\-insecure: \fI<domain name>
663 Sets domain name to be insecure, DNSSEC chain of trust is ignored towards
664 the domain name. So a trust anchor above the domain name can not make the
665 domain secure with a DS record, such a DS record is then ignored.
666 Also keys from DLV are ignored for the domain. Can be given multiple times
667 to specify multiple domains that are treated as if unsigned. If you set
668 trust anchors for the domain they override this setting (and the domain
671 This can be useful if you want to make sure a trust anchor for external
672 lookups does not affect an (unsigned) internal domain. A DS record
673 externally can create validation failures for that internal domain.
675 .B val\-override\-date: \fI<rrsig\-style date spec>
676 Default is "" or "0", which disables this debugging feature. If enabled by
677 giving a RRSIG style date, that date is used for verifying RRSIG inception
678 and expiration dates, instead of the current date. Do not set this unless
679 you are debugging signature inception and expiration. The value \-1 ignores
680 the date altogether, useful for some special applications.
682 .B val\-sig\-skew\-min: \fI<seconds>
683 Minimum number of seconds of clock skew to apply to validated signatures.
684 A value of 10% of the signature lifetime (expiration \- inception) is
685 used, capped by this setting. Default is 3600 (1 hour) which allows for
686 daylight savings differences. Lower this value for more strict checking
687 of short lived signatures.
689 .B val\-sig\-skew\-max: \fI<seconds>
690 Maximum number of seconds of clock skew to apply to validated signatures.
691 A value of 10% of the signature lifetime (expiration \- inception)
692 is used, capped by this setting. Default is 86400 (24 hours) which
693 allows for timezone setting problems in stable domains. Setting both
694 min and max very low disables the clock skew allowances. Setting both
695 min and max very high makes the validator check the signature timestamps
698 .B val\-bogus\-ttl: \fI<number>
699 The time to live for bogus data. This is data that has failed validation;
700 due to invalid signatures or other checks. The TTL from that data cannot be
701 trusted, and this value is used instead. The value is in seconds, default 60.
702 The time interval prevents repeated revalidation of bogus data.
704 .B val\-clean\-additional: \fI<yes or no>
705 Instruct the validator to remove data from the additional section of secure
706 messages that are not signed properly. Messages that are insecure, bogus,
707 indeterminate or unchecked are not affected. Default is yes. Use this setting
708 to protect the users that rely on this validator for authentication from
709 protentially bad data in the additional section.
711 .B val\-log\-level: \fI<number>
712 Have the validator print validation failures to the log. Regardless of
713 the verbosity setting. Default is 0, off. At 1, for every user query
714 that fails a line is printed to the logs. This way you can monitor what
715 happens with validation. Use a diagnosis tool, such as dig or drill,
716 to find out why validation is failing for these queries. At 2, not only
717 the query that failed is printed but also the reason why unbound thought
718 it was wrong and which server sent the faulty data.
720 .B val\-permissive\-mode: \fI<yes or no>
721 Instruct the validator to mark bogus messages as indeterminate. The security
722 checks are performed, but if the result is bogus (failed security), the
723 reply is not withheld from the client with SERVFAIL as usual. The client
724 receives the bogus data. For messages that are found to be secure the AD bit
725 is set in replies. Also logging is performed as for full validation.
726 The default value is "no".
728 .B ignore\-cd\-flag: \fI<yes or no>
729 Instruct unbound to ignore the CD flag from clients and refuse to
730 return bogus answers to them. Thus, the CD (Checking Disabled) flag
731 does not disable checking any more. This is useful if legacy (w2008)
732 servers that set the CD flag but cannot validate DNSSEC themselves are
733 the clients, and then unbound provides them with DNSSEC protection.
734 The default value is "no".
736 .B val\-nsec3\-keysize\-iterations: \fI<"list of values">
737 List of keysize and iteration count values, separated by spaces, surrounded
738 by quotes. Default is "1024 150 2048 500 4096 2500". This determines the
739 maximum allowed NSEC3 iteration count before a message is simply marked
740 insecure instead of performing the many hashing iterations. The list must
741 be in ascending order and have at least one entry. If you set it to
742 "1024 65535" there is no restriction to NSEC3 iteration values.
743 This table must be kept short; a very long list could cause slower operation.
745 .B add\-holddown: \fI<seconds>
746 Instruct the \fBauto\-trust\-anchor\-file\fR probe mechanism for RFC5011
747 autotrust updates to add new trust anchors only after they have been
748 visible for this time. Default is 30 days as per the RFC.
750 .B del\-holddown: \fI<seconds>
751 Instruct the \fBauto\-trust\-anchor\-file\fR probe mechanism for RFC5011
752 autotrust updates to remove revoked trust anchors after they have been
753 kept in the revoked list for this long. Default is 30 days as per
756 .B keep\-missing: \fI<seconds>
757 Instruct the \fBauto\-trust\-anchor\-file\fR probe mechanism for RFC5011
758 autotrust updates to remove missing trust anchors after they have been
759 unseen for this long. This cleans up the state file if the target zone
760 does not perform trust anchor revocation, so this makes the auto probe
761 mechanism work with zones that perform regular (non\-5011) rollovers.
762 The default is 366 days. The value 0 does not remove missing anchors,
765 .B key\-cache\-size: \fI<number>
766 Number of bytes size of the key cache. Default is 4 megabytes.
767 A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
768 or gigabytes (1024*1024 bytes in a megabyte).
770 .B key\-cache\-slabs: \fI<number>
771 Number of slabs in the key cache. Slabs reduce lock contention by threads.
772 Must be set to a power of 2. Setting (close) to the number of cpus is a
775 .B neg\-cache\-size: \fI<number>
776 Number of bytes size of the aggressive negative cache. Default is 1 megabyte.
777 A plain number is in bytes, append 'k', 'm' or 'g' for kilobytes, megabytes
778 or gigabytes (1024*1024 bytes in a megabyte).
780 .B unblock\-lan\-zones: \fI<yesno>
781 Default is disabled. If enabled, then for private address space,
782 the reverse lookups are no longer filtered. This allows unbound when
783 running as dns service on a host where it provides service for that host,
784 to put out all of the queries for the 'lan' upstream. When enabled,
785 only localhost, 127.0.0.1 reverse and ::1 reverse zones are configured
786 with default local zones. Disable the option when unbound is running
787 as a (DHCP-) DNS network resolver for a group of machines, where such
788 lookups should be filtered (RFC compliance), this also stops potential
789 data leakage about the local network to the upstream DNS servers.
791 .B local\-zone: \fI<zone> <type>
792 Configure a local zone. The type determines the answer to give if
793 there is no match from local\-data. The types are deny, refuse, static,
794 transparent, redirect, nodefault, typetransparent, and are explained
795 below. After that the default settings are listed. Use local\-data: to
796 enter data into the local zone. Answers for local zones are authoritative
797 DNS answers. By default the zones are class IN.
799 If you need more complicated authoritative data, with referrals, wildcards,
800 CNAME/DNAME support, or DNSSEC authoritative service, setup a stub\-zone for
801 it as detailed in the stub zone section below.
804 Do not send an answer, drop the query.
805 If there is a match from local data, the query is answered.
808 Send an error message reply, with rcode REFUSED.
809 If there is a match from local data, the query is answered.
812 If there is a match from local data, the query is answered.
813 Otherwise, the query is answered with nodata or nxdomain.
814 For a negative answer a SOA is included in the answer if present
815 as local\-data for the zone apex domain.
817 \h'5'\fItransparent\fR
818 If there is a match from local data, the query is answered.
819 Otherwise if the query has a different name, the query is resolved normally.
820 If the query is for a name given in localdata but no such type of data is
821 given in localdata, then a noerror nodata answer is returned.
822 If no local\-zone is given local\-data causes a transparent zone
823 to be created by default.
825 \h'5'\fItypetransparent\fR
826 If there is a match from local data, the query is answered. If the query
827 is for a different name, or for the same name but for a different type,
828 the query is resolved normally. So, similar to transparent but types
829 that are not listed in local data are resolved normally, so if an A record
830 is in the local data that does not cause a nodata reply for AAAA queries.
833 The query is answered from the local data for the zone name.
834 There may be no local data beneath the zone name.
835 This answers queries for the zone, and all subdomains of the zone
836 with the local data for the zone.
837 It can be used to redirect a domain to return a different address record
838 to the end user, with
839 local\-zone: "example.com." redirect and
840 local\-data: "example.com. A 127.0.0.1"
841 queries for www.example.com and www.foo.example.com are redirected, so
842 that users with web browsers cannot access sites with suffix example.com.
845 Used to turn off default contents for AS112 zones. The other types
846 also turn off default contents for the zone. The 'nodefault' option
847 has no other effect than turning off default contents for the
850 The default zones are localhost, reverse 127.0.0.1 and ::1, and the AS112
851 zones. The AS112 zones are reverse DNS zones for private use and reserved
852 IP addresses for which the servers on the internet cannot provide correct
853 answers. They are configured by default to give nxdomain (no reverse
854 information) answers. The defaults can be turned off by specifying your
855 own local\-zone of that name, or using the 'nodefault' type. Below is a
856 list of the default zone contents.
859 The IP4 and IP6 localhost information is given. NS and SOA records are provided
860 for completeness and to satisfy some DNS update tools. Default content:
862 local\-zone: "localhost." static
863 local\-data: "localhost. 10800 IN NS localhost."
864 local\-data: "localhost. 10800 IN
865 SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
866 local\-data: "localhost. 10800 IN A 127.0.0.1"
867 local\-data: "localhost. 10800 IN AAAA ::1"
870 \h'5'\fIreverse IPv4 loopback\fR
873 local\-zone: "127.in\-addr.arpa." static
874 local\-data: "127.in\-addr.arpa. 10800 IN NS localhost."
875 local\-data: "127.in\-addr.arpa. 10800 IN
876 SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
877 local\-data: "1.0.0.127.in\-addr.arpa. 10800 IN
881 \h'5'\fIreverse IPv6 loopback\fR
884 local\-zone: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
885 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." static
886 local\-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
887 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
889 local\-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
890 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
891 SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
892 local\-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
893 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
897 \h'5'\fIreverse RFC1918 local use zones\fR
898 Reverse data for zones 10.in\-addr.arpa, 16.172.in\-addr.arpa to
899 31.172.in\-addr.arpa, 168.192.in\-addr.arpa.
900 The \fBlocal\-zone:\fR is set static and as \fBlocal\-data:\fR SOA and NS
901 records are provided.
903 \h'5'\fIreverse RFC3330 IP4 this, link\-local, testnet and broadcast\fR
904 Reverse data for zones 0.in\-addr.arpa, 254.169.in\-addr.arpa,
905 2.0.192.in\-addr.arpa (TEST NET 1), 100.51.198.in\-addr.arpa (TEST NET 2),
906 113.0.203.in\-addr.arpa (TEST NET 3), 255.255.255.255.in\-addr.arpa.
907 And from 64.100.in\-addr.arpa to 127.100.in\-addr.arpa (Shared Address Space).
909 \h'5'\fIreverse RFC4291 IP6 unspecified\fR
910 Reverse data for zone
912 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
913 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.
916 \h'5'\fIreverse RFC4193 IPv6 Locally Assigned Local Addresses\fR
917 Reverse data for zone D.F.ip6.arpa.
919 \h'5'\fIreverse RFC4291 IPv6 Link Local Addresses\fR
920 Reverse data for zones 8.E.F.ip6.arpa to B.E.F.ip6.arpa.
922 \h'5'\fIreverse IPv6 Example Prefix\fR
923 Reverse data for zone 8.B.D.0.1.0.0.2.ip6.arpa. This zone is used for
924 tutorials and examples. You can remove the block on this zone with:
926 local\-zone: 8.B.D.0.1.0.0.2.ip6.arpa. nodefault
928 You can also selectively unblock a part of the zone by making that part
929 transparent with a local\-zone statement.
930 This also works with the other default zones.
931 .\" End of local-zone listing.
933 .B local\-data: \fI"<resource record string>"
934 Configure local data, which is served in reply to queries for it.
935 The query has to match exactly unless you configure the local\-zone as
936 redirect. If not matched exactly, the local\-zone type determines
937 further processing. If local\-data is configured that is not a subdomain of
938 a local\-zone, a transparent local\-zone is configured.
939 For record types such as TXT, use single quotes, as in
940 local\-data: 'example. TXT "text"'.
942 If you need more complicated authoritative data, with referrals, wildcards,
943 CNAME/DNAME support, or DNSSEC authoritative service, setup a stub\-zone for
944 it as detailed in the stub zone section below.
946 .B local\-data\-ptr: \fI"IPaddr name"
947 Configure local data shorthand for a PTR record with the reversed IPv4 or
948 IPv6 address and the host name. For example "192.0.2.4 www.example.com".
949 TTL can be inserted like this: "2001:DB8::4 7200 www.example.com"
950 .SS "Remote Control Options"
953 clause are the declarations for the remote control facility. If this is
954 enabled, the \fIunbound\-control\fR(8) utility can be used to send
955 commands to the running unbound server. The server uses these clauses
956 to setup SSLv3 / TLSv1 security for the connection. The
957 \fIunbound\-control\fR(8) utility also reads the \fBremote\-control\fR
958 section for options. To setup the correct self\-signed certificates use the
959 \fIunbound\-control\-setup\fR(8) utility.
961 .B control\-enable: \fI<yes or no>
962 The option is used to enable remote control, default is "no".
963 If turned off, the server does not listen for control commands.
965 .B control\-interface: \fI<ip address or path>
966 Give IPv4 or IPv6 addresses or local socket path to listen on for
968 By default localhost (127.0.0.1 and ::1) is listened to.
969 Use 0.0.0.0 and ::0 to listen to all interfaces.
970 If you change this and permissions have been dropped, you must restart
971 the server for the change to take effect.
973 .B control\-port: \fI<port number>
974 The port number to listen on for IPv4 or IPv6 control interfaces,
976 If you change this and permissions have been dropped, you must restart
977 the server for the change to take effect.
979 .B control\-use\-cert: \fI<yes or no>
980 Whether to require certificate authentication of control connections.
981 The default is "yes".
982 This should not be changed unless there are other mechanisms in place
983 to prevent untrusted users from accessing the remote control
986 .B server\-key\-file: \fI<private key file>
987 Path to the server private key, by default unbound_server.key.
988 This file is generated by the \fIunbound\-control\-setup\fR utility.
989 This file is used by the unbound server, but not by \fIunbound\-control\fR.
991 .B server\-cert\-file: \fI<certificate file.pem>
992 Path to the server self signed certificate, by default unbound_server.pem.
993 This file is generated by the \fIunbound\-control\-setup\fR utility.
994 This file is used by the unbound server, and also by \fIunbound\-control\fR.
996 .B control\-key\-file: \fI<private key file>
997 Path to the control client private key, by default unbound_control.key.
998 This file is generated by the \fIunbound\-control\-setup\fR utility.
999 This file is used by \fIunbound\-control\fR.
1001 .B control\-cert\-file: \fI<certificate file.pem>
1002 Path to the control client certificate, by default unbound_control.pem.
1003 This certificate has to be signed with the server certificate.
1004 This file is generated by the \fIunbound\-control\-setup\fR utility.
1005 This file is used by \fIunbound\-control\fR.
1006 .SS "Stub Zone Options"
1008 There may be multiple
1010 clauses. Each with a name: and zero or more hostnames or IP addresses.
1011 For the stub zone this list of nameservers is used. Class IN is assumed.
1012 The servers should be authority servers, not recursors; unbound performs
1013 the recursive processing itself for stub zones.
1015 The stub zone can be used to configure authoritative data to be used
1016 by the resolver that cannot be accessed using the public internet servers.
1017 This is useful for company\-local data or private zones. Setup an
1018 authoritative server on a different host (or different port). Enter a config
1019 entry for unbound with
1021 <ip address of host[@port]>.
1022 The unbound resolver can then access the data, without referring to the
1023 public internet for it.
1025 This setup allows DNSSEC signed zones to be served by that
1026 authoritative server, in which case a trusted key entry with the public key
1027 can be put in config, so that unbound can validate the data and set the AD
1028 bit on replies for the private zone (authoritative servers do not set the
1029 AD bit). This setup makes unbound capable of answering queries for the
1030 private zone, and can even set the AD bit ('authentic'), but the AA
1031 ('authoritative') bit is not set on these replies.
1033 .B name: \fI<domain name>
1034 Name of the stub zone.
1036 .B stub\-host: \fI<domain name>
1037 Name of stub zone nameserver. Is itself resolved before it is used.
1039 .B stub\-addr: \fI<IP address>
1040 IP address of stub zone nameserver. Can be IP 4 or IP 6.
1041 To use a nondefault port for DNS communication append '@' with the port number.
1043 .B stub\-prime: \fI<yes or no>
1044 This option is by default off. If enabled it performs NS set priming,
1045 which is similar to root hints, where it starts using the list of nameservers
1046 currently published by the zone. Thus, if the hint list is slightly outdated,
1047 the resolver picks up a correct list online.
1049 .B stub\-first: \fI<yes or no>
1050 If enabled, a query is attempted without the stub clause if it fails.
1051 The data could not be retrieved and would have caused SERVFAIL because
1052 the servers are unreachable, instead it is tried without this clause.
1054 .SS "Forward Zone Options"
1056 There may be multiple
1058 clauses. Each with a \fBname:\fR and zero or more hostnames or IP
1059 addresses. For the forward zone this list of nameservers is used to
1060 forward the queries to. The servers listed as \fBforward\-host:\fR and
1061 \fBforward\-addr:\fR have to handle further recursion for the query. Thus,
1062 those servers are not authority servers, but are (just like unbound is)
1063 recursive servers too; unbound does not perform recursion itself for the
1064 forward zone, it lets the remote server do it. Class IN is assumed.
1065 A forward\-zone entry with name "." and a forward\-addr target will
1066 forward all queries to that other server (unless it can answer from
1069 .B name: \fI<domain name>
1070 Name of the forward zone.
1072 .B forward\-host: \fI<domain name>
1073 Name of server to forward to. Is itself resolved before it is used.
1075 .B forward\-addr: \fI<IP address>
1076 IP address of server to forward to. Can be IP 4 or IP 6.
1077 To use a nondefault port for DNS communication append '@' with the port number.
1079 .B forward\-first: \fI<yes or no>
1080 If enabled, a query is attempted without the forward clause if it fails.
1081 The data could not be retrieved and would have caused SERVFAIL because
1082 the servers are unreachable, instead it is tried without this clause.
1084 .SS "Python Module Options"
1088 clause gives the settings for the \fIpython\fR(1) script module. This module
1089 acts like the iterator and validator modules do, on queries and answers.
1090 To enable the script module it has to be compiled into the daemon,
1091 and the word "python" has to be put in the \fBmodule\-config:\fR option
1092 (usually first, or between the validator and iterator).
1094 .B python\-script: \fI<python file>\fR
1095 The script file to load.
1096 .SS "DNS64 Module Options"
1098 The dns64 module must be configured in the \fBmodule\-config:\fR "dns64
1099 validator iterator" directive and be compiled into the daemon to be
1100 enabled. These settings go in the \fBserver:\fR section.
1102 .B dns64\-prefix: \fI<IPv6 prefix>\fR
1103 This sets the DNS64 prefix to use to synthesize AAAA records with.
1104 It must be /96 or shorter. The default prefix is 64:ff9b::/96.
1106 .B dns64\-synthall: \fI<yes or no>\fR
1107 Debug option, default no. If enabled, synthesize all AAAA records
1108 despite the presence of actual AAAA records.
1109 .SH "MEMORY CONTROL EXAMPLE"
1110 In the example config settings below memory usage is reduced. Some service
1111 levels are lower, notable very large data and a high TCP load are no longer
1112 supported. Very large data and high TCP loads are exceptional for the DNS.
1113 DNSSEC validation is enabled, just add trust anchors.
1114 If you do not have to worry about programs using more than 3 Mb of memory,
1115 the below example is not for you. Use the defaults to receive full service,
1116 which on BSD\-32bit tops out at 30\-40 Mb after heavy usage.
1119 # example settings that reduce memory usage
1122 outgoing\-num\-tcp: 1 # this limits TCP service, uses less buffers.
1123 incoming\-num\-tcp: 1
1124 outgoing\-range: 60 # uses less memory, but less performance.
1125 msg\-buffer\-size: 8192 # note this limits service, 'no huge stuff'.
1126 msg\-cache\-size: 100k
1127 msg\-cache\-slabs: 1
1128 rrset\-cache\-size: 100k
1129 rrset\-cache\-slabs: 1
1130 infra\-cache\-numhosts: 200
1131 infra\-cache\-slabs: 1
1132 key\-cache\-size: 100k
1133 key\-cache\-slabs: 1
1134 neg\-cache\-size: 10k
1135 num\-queries\-per\-thread: 30
1136 target\-fetch\-policy: "2 1 0 0 0 0"
1137 harden\-large\-queries: "yes"
1138 harden\-short\-bufsize: "yes"
1143 default unbound working directory.
1150 .I /var/unbound/unbound.conf
1151 unbound configuration file.
1153 .I /var/unbound/unbound.pid
1154 default unbound pidfile with process ID of the running daemon.
1157 unbound log file. default is to log to
1161 \fIunbound\-checkconf\fR(8).
1164 was written by NLnet Labs. Please see CREDITS file
1165 in the distribution for further details.
projects / FreeBSD / FreeBSD.git / blob