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unbound.conf(5)			unbound	1.4.22		       unbound.conf(5)

NAME
       unbound.conf - Unbound configuration file.

SYNOPSIS
       unbound.conf

DESCRIPTION
       unbound.conf  is	used to	configure unbound(8).  The file	format has at-
       tributes	and values. Some attributes have attributes inside them.   The
       notation	is: attribute: value.

       Comments	 start with # and last to the end of line. Empty lines are ig-
       nored as	is whitespace at the beginning of a line.

       The utility unbound-checkconf(8)	can  be	 used  to  check  unbound.conf
       prior to	usage.

EXAMPLE
       An  example  config  file is shown below. Copy this to /etc/unbound/un-
       bound.conf and start the	server with:

	    $ unbound -c /etc/unbound/unbound.conf

       Most settings are the defaults. Stop the	server with:

	    $ kill `cat	/etc/unbound/unbound.pid`

       Below is	a minimal config file. The source distribution contains	an ex-
       tensive example.conf file with all the options.

       # unbound.conf(5) config	file for unbound(8).
       server:
	    directory: "/etc/unbound"
	    username: unbound
	    # make sure	unbound	can access entropy from	inside the chroot.
	    # e.g. on linux the	use these commands (on BSD, devfs(8) is	used):
	    #	   mount --bind	-n /dev/random /etc/unbound/dev/random
	    # and  mount --bind	-n /dev/log /etc/unbound/dev/log
	    chroot: "/etc/unbound"
	    # logfile: "/etc/unbound/unbound.log"  #uncomment to use logfile.
	    pidfile: "/etc/unbound/unbound.pid"
	    # verbosity: 1	# uncomment and	increase to get	more logging.
	    # listen on	all interfaces,	answer queries from the	local subnet.
	    interface: 0.0.0.0
	    interface: ::0
	    access-control: 10.0.0.0/8 allow
	    access-control: 2001:DB8::/64 allow

FILE FORMAT
       There  must be whitespace between keywords. Attribute keywords end with
       a colon ':'. An attribute is followed by	its containing attributes,  or
       a value.

       Files  can be included using the	include: directive. It can appear any-
       where, it accepts a single file name as argument.  Processing continues
       as  if  the text	from the included file was copied into the config file
       at that point.  If also using chroot, using full	path names for the in-
       cluded  files  works, relative pathnames	for the	included names work if
       the directory where the daemon is started equals	its chroot/working di-
       rectory.	 Wildcards can be used to include multiple files, see glob(7).

   Server Options
       These options are part of the server: clause.

       verbosity: _number_
	      The  verbosity  number, level 0 means no verbosity, only errors.
	      Level 1 gives operational	information. Level  2  gives  detailed
	      operational  information.	Level 3	gives query level information,
	      output per query.	 Level 4 gives	algorithm  level  information.
	      Level 5 logs client identification for cache misses.  Default is
	      level 1.	The verbosity can also be increased from the  command-
	      line, see	unbound(8).

       statistics-interval: _seconds_
	      The number of seconds between printing statistics	to the log for
	      every thread.  Disable with value	0 or "". Default is  disabled.
	      The  histogram  statistics are only printed if replies were sent
	      during  the  statistics  interval,  requestlist  statistics  are
	      printed  for every interval (but can be 0).  This	is because the
	      median calculation requires data to be present.

       statistics-cumulative: _yes or no_
	      If enabled, statistics are cumulative  since  starting  unbound,
	      without  clearing	the statistics counters	after logging the sta-
	      tistics. Default is no.

       extended-statistics: _yes or no_
	      If enabled, extended statistics are  printed  from  unbound-con-
	      trol(8).	 Default is off, because keeping track of more statis-
	      tics takes time.	The counters are listed	in unbound-control(8).

       num-threads: _number_
	      The number of threads to create to serve clients.	Use 1  for  no
	      threading.

       port: _port number_
	      The  port	 number,  default  53, on which	the server responds to
	      queries.

       interface: _ip address[@port]_
	      Interface	to use to connect to the network.  This	 interface  is
	      listened to for queries from clients, and	answers	to clients are
	      given from it.  Can be given multiple times to work  on  several
	      interfaces. If none are given the	default	is to listen to	local-
	      host.  The interfaces are	not changed on a  reload  (kill	 -HUP)
	      but  only	on restart.  A port number can be specified with @port
	      (without spaces between interface	and port number), if not spec-
	      ified the	default	port (from port) is used.

       ip-address: _ip address[@port]_
	      Same as interface: (for easy of compatibility with nsd.conf).

       interface-automatic: _yes or no_
	      Detect source interface on UDP queries and copy them to replies.
	      This feature is experimental, and	needs support in your  OS  for
	      particular socket	options.  Default value	is no.

       outgoing-interface: _ip address_
	      Interface	 to  use  to connect to	the network. This interface is
	      used to send queries to authoritative servers and	receive	 their
	      replies.	Can  be	given multiple times to	work on	several	inter-
	      faces. If	none are given the default  (all)  is  used.  You  can
	      specify  the  same  interfaces in	interface: and outgoing-inter-
	      face: lines, the interfaces are then  used  for  both  purposes.
	      Outgoing	queries	 are  sent  via	a random outgoing interface to
	      counter spoofing.

       outgoing-range: _number_
	      Number of	ports to open. This number of file descriptors can  be
	      opened  per  thread. Must	be at least 1. Default depends on com-
	      pile options. Larger numbers need	extra resources	from the oper-
	      ating system.  For performance a a very large value is best, use
	      libevent to make this possible.

       outgoing-port-permit: _port number or range_
	      Permit unbound to	open this port or range	of ports  for  use  to
	      send  queries.   A larger	number of permitted outgoing ports in-
	      creases resilience against spoofing attempts.  Make  sure	 these
	      ports  are  not  needed by other daemons.	 By default only ports
	      above 1024 that have not been assigned by	IANA are used.	Give a
	      port number or a range of	the form "low-high", without spaces.

	      The  outgoing-port-permit	and outgoing-port-avoid	statements are
	      processed	in the line order of the config	file, adding the  per-
	      mitted  ports  and subtracting the avoided ports from the	set of
	      allowed ports.  The processing starts with the  non  IANA	 allo-
	      cated ports above	1024 in	the set	of allowed ports.

       outgoing-port-avoid: _port number or range_
	      Do  not  permit  unbound to open this port or range of ports for
	      use to send queries. Use this to make sure unbound does not grab
	      a	 port  that  another  daemon needs. The	port is	avoided	on all
	      outgoing interfaces, both	IP4 and	IP6.  By  default  only	 ports
	      above 1024 that have not been assigned by	IANA are used.	Give a
	      port number or a range of	the form "low-high", without spaces.

       outgoing-num-tcp: _number_
	      Number of	outgoing TCP buffers to	allocate per  thread.  Default
	      is  10. If set to	0, or if do_tcp	is "no", no TCP	queries	to au-
	      thoritative servers are done.

       incoming-num-tcp: _number_
	      Number of	incoming TCP buffers to	allocate per  thread.  Default
	      is  10.  If  set to 0, or	if do_tcp is "no", no TCP queries from
	      clients are accepted.

       edns-buffer-size: _number_
	      Number of	bytes size to advertise	as the EDNS reassembly	buffer
	      size.   This  is	the  value put into datagrams over UDP towards
	      peers.  The actual buffer	size is	determined by  msg-buffer-size
	      (both for	TCP and	UDP).  Do not set higher than that value.  De-
	      fault is 4096 which is RFC recommended.  If you have  fragmenta-
	      tion reassembly problems,	usually	seen as	timeouts, then a value
	      of 1480 can fix it.  Setting  to	512  bypasses  even  the  most
	      stringent	 path  MTU problems, but is seen as extreme, since the
	      amount of	TCP fallback generated is excessive (probably also for
	      this resolver, consider tuning the outgoing tcp number).

       max-udp-size: _number_
	      Maximum  UDP response size (not applied to TCP response).	 65536
	      disables the udp response	size maximum, and uses the choice from
	      the  client,  always.  Suggested values are 512 to 4096. Default
	      is 4096.

       msg-buffer-size:	_number_
	      Number of	bytes size of the message buffers.  Default  is	 65552
	      bytes,  enough  for 64 Kb	packets, the maximum DNS message size.
	      No message larger	than this can be sent or received. Can be  re-
	      duced  to	 use less memory, but some requests for	DNS data, such
	      as for huge resource records, will result	in a SERVFAIL reply to
	      the client.

       msg-cache-size: _number_
	      Number  of  bytes	 size  of  the	message	 cache.	 Default  is 4
	      megabytes.  A plain number is in bytes, append 'k', 'm'  or  'g'
	      for  kilobytes,  megabytes  or  gigabytes	 (1024*1024 bytes in a
	      megabyte).

       msg-cache-slabs:	_number_
	      Number of	slabs in the message cache.  Slabs  reduce  lock  con-
	      tention  by  threads.   Must  be	set  to	 a power of 2. Setting
	      (close) to the number of cpus is a reasonable guess.

       num-queries-per-thread: _number_
	      The number of queries that every thread will service  simultane-
	      ously.   If  more	 queries  arrive  that	need servicing,	and no
	      queries can  be  jostled	out  (see  jostle-timeout),  then  the
	      queries  are  dropped.  This forces the client to	resend after a
	      timeout; allowing	the  server  time  to  work  on	 the  existing
	      queries. Default depends on compile options, 512 or 1024.

       jostle-timeout: _msec_
	      Timeout  used when the server is very busy.  Set to a value that
	      usually results in one roundtrip to the authority	 servers.   If
	      too  many	queries	arrive,	then 50% of the	queries	are allowed to
	      run to completion, and the other 50% are replaced	with  the  new
	      incoming	query  if  they	have already spent more	than their al-
	      lowed time.  This	protects against denial	 of  service  by  slow
	      queries or high query rates.  Default 200	milliseconds.  The ef-
	      fect is that the qps for long-lasting  queries  is  about	 (num-
	      queriesperthread	/  2)  /  (average time	for such long queries)
	      qps.  The	qps  for  short	 queries  can  be  about  (numqueries-
	      perthread	 /  2)	/  (jostletimeout  in  whole  seconds) qps per
	      thread, about (1024/2)*5 = 2560 qps by default.

       delay-close: _msec_
	      Extra delay for timeouted	UDP ports before they are  closed,  in
	      msec.   Default  is 0, and that disables it.  This prevents very
	      delayed answer packets from  the	upstream  (recursive)  servers
	      from  bouncing  against closed ports and setting off all sort of
	      close-port counters, with	eg. 1500 msec.	When  timeouts	happen
	      you  need	extra sockets, it checks the ID	and remote IP of pack-
	      ets, and unwanted	packets	 are  added  to	 the  unwanted	packet
	      counter.

       so-rcvbuf: _number_
	      If  not 0, then set the SO_RCVBUF	socket option to get more buf-
	      fer space	on UDP port 53 incoming	queries.  So that short	spikes
	      on  busy	servers	 do  not  drop packets (see counter in netstat
	      -su).  Default is	0 (use system value).  Otherwise,  the	number
	      of  bytes	to ask for, try	"4m" on	a busy server.	The OS caps it
	      at a maximum, on linux unbound needs root	permission  to	bypass
	      the  limit,  or  the admin can use sysctl	net.core.rmem_max.  On
	      BSD change kern.ipc.maxsockbuf in	/etc/sysctl.conf.  On  OpenBSD
	      change header and	recompile kernel. On Solaris ndd -set /dev/udp
	      udp_max_buf 8388608.

       so-sndbuf: _number_
	      If not 0,	then set the SO_SNDBUF socket option to	get more  buf-
	      fer  space  on UDP port 53 outgoing queries.  This for very busy
	      servers handles spikes in	answer traffic,	otherwise  'send:  re-
	      source temporarily unavailable' can get logged, the buffer over-
	      run is also visible by netstat -su.  Default is  0  (use	system
	      value).	Specify	 the number of bytes to	ask for, try "4m" on a
	      very busy	server.	 The OS	caps it	at a maximum, on linux unbound
	      needs  root permission to	bypass the limit, or the admin can use
	      sysctl net.core.wmem_max.	 On BSD, Solaris changes  are  similar
	      to so-rcvbuf.

       so-reuseport: _yes or no_
	      If  yes,	then  open  dedicated  listening  sockets for incoming
	      queries for each thread and try to set the  SO_REUSEPORT	socket
	      option  on  each	socket.	  May  distribute  incoming queries to
	      threads more evenly.  Default is no.  Only supported on Linux >=
	      3.9.   You  can  enable it (on any platform and kernel), it then
	      attempts to open the port	and passes the option if it was	avail-
	      able  at compile time, if	that works it is used, if it fails, it
	      continues	silently (unless verbosity 3) without the option.

       rrset-cache-size: _number_
	      Number of	bytes size of the RRset	cache. Default is 4 megabytes.
	      A	 plain	number	is  in bytes, append 'k', 'm' or 'g' for kilo-
	      bytes, megabytes or gigabytes (1024*1024 bytes in	a megabyte).

       rrset-cache-slabs: _number_
	      Number of	slabs in the RRset cache. Slabs	reduce lock contention
	      by threads.  Must	be set to a power of 2.

       cache-max-ttl: _seconds_
	      Time  to	live maximum for RRsets	and messages in	the cache. De-
	      fault is 86400 seconds (1	day). If the  maximum  kicks  in,  re-
	      sponses  to  clients  still  get	decrementing TTLs based	on the
	      original (larger)	values.	 When the internal  TTL	 expires,  the
	      cache  item has expired.	Can be set lower to force the resolver
	      to query for data	often, and not trust (very large) TTL values.

       cache-min-ttl: _seconds_
	      Time to live minimum for RRsets and messages in the  cache.  De-
	      fault is 0.  If the the minimum kicks in,	the data is cached for
	      longer than the domain owner intended, and thus less queries are
	      made to look up the data.	 Zero makes sure the data in the cache
	      is as the	domain owner intended, higher values, especially  more
	      than an hour or so, can lead to trouble as the data in the cache
	      does not match up	with the actual	data any more.

       infra-host-ttl: _seconds_
	      Time to live for entries in the host cache. The host cache  con-
	      tains  roundtrip	timing,	lameness and EDNS support information.
	      Default is 900.

       infra-cache-slabs: _number_
	      Number of	slabs in the infrastructure cache. Slabs  reduce  lock
	      contention by threads. Must be set to a power of 2.

       infra-cache-numhosts: _number_
	      Number  of  hosts	 for  which  information is cached. Default is
	      10000.

       do-ip4: _yes or no_
	      Enable or	disable	whether	ip4 queries are	 answered  or  issued.
	      Default is yes.

       do-ip6: _yes or no_
	      Enable  or  disable  whether ip6 queries are answered or issued.
	      Default is yes.  If disabled, queries are	not answered on	 IPv6,
	      and queries are not sent on IPv6 to the internet nameservers.

       do-udp: _yes or no_
	      Enable  or  disable  whether UDP queries are answered or issued.
	      Default is yes.

       do-tcp: _yes or no_
	      Enable or	disable	whether	TCP queries are	 answered  or  issued.
	      Default is yes.

       tcp-upstream: _yes or no_
	      Enable  or disable whether the upstream queries use TCP only for
	      transport.  Default is no.  Useful in tunneling scenarios.

       ssl-upstream: _yes or no_
	      Enabled or disable whether the upstream queries use SSL only for
	      transport.   Default is no.  Useful in tunneling scenarios.  The
	      SSL contains plain DNS in	TCP wireformat.	 The other server must
	      support this (see	ssl-service-key).

       ssl-service-key:	_file_
	      If  enabled, the server provider SSL service on its TCP sockets.
	      The clients have to use ssl-upstream: yes.  The file is the pri-
	      vate  key	for the	TLS session.  The public certificate is	in the
	      ssl-service-pem file.  Default is	"", turned  off.   Requires  a
	      restart (a reload	is not enough) if changed, because the private
	      key is read while	root permissions are held  and	before	chroot
	      (if  any).  Normal DNS TCP service is not	provided and gives er-
	      rors, this service is best run with a different port: config  or
	      @port suffixes in	the interface config.

       ssl-service-pem:	_file_
	      The  public  key	certificate pem	file for the ssl service.  De-
	      fault is "", turned off.

       ssl-port: _number_
	      The port number on which to provide  TCP	SSL  service,  default
	      443, only	interfaces configured with that	port number as @number
	      get the SSL service.

       do-daemonize: _yes or no_
	      Enable or	disable	whether	the  unbound  server  forks  into  the
	      background as a daemon. Default is yes.

       access-control: _IP netblock_ _action_
	      The  netblock  is	 given as an IP4 or IP6	address	with /size ap-
	      pended for a classless network block. The	action	can  be	 deny,
	      refuse, allow, allow_snoop, deny_non_local or refuse_non_local.

	      The action deny stops queries from hosts from that netblock.

	      The  action  refuse stops	queries	too, but sends a DNS rcode RE-
	      FUSED error message back.

	      The action allow gives access to clients from that netblock.  It
	      gives  only  access  for recursion clients (which	is what	almost
	      all clients need).  Nonrecursive queries are refused.

	      The allow	action does allow nonrecursive queries to  access  the
	      local-data that is configured.  The reason is that this does not
	      involve the  unbound  server  recursive  lookup  algorithm,  and
	      static data is served in the reply.  This	supports normal	opera-
	      tions where nonrecursive queries are made	for the	 authoritative
	      data.   For  nonrecursive	 queries  any replies from the dynamic
	      cache are	refused.

	      The action allow_snoop gives nonrecursive	access too.  This give
	      both  recursive  and non recursive access.  The name allow_snoop
	      refers to	 cache	snooping,  a  technique	 to  use  nonrecursive
	      queries  to  examine  the	 cache	contents (for malicious	acts).
	      However, nonrecursive queries can	also be	a  valuable  debugging
	      tool (when you want to examine the cache contents). In that case
	      use allow_snoop for your administration host.

	      By default only localhost	is allowed, the	rest is	refused.   The
	      default  is  refused, because that is protocol-friendly. The DNS
	      protocol is not designed to handle dropped packets due  to  pol-
	      icy,  and	 dropping  may	result in (possibly excessive) retried
	      queries.

	      The deny_non_local and refuse_non_local settings are  for	 hosts
	      that are only allowed to query for the authoritative local-data,
	      they are not allowed full	recursion but only  the	 static	 data.
	      With  deny_non_local,  messages that are disallowed are dropped,
	      with refuse_non_local they receive error code REFUSED.

       chroot: _directory_
	      If chroot	is enabled, you	should pass the	configfile  (from  the
	      commandline)  as	a  full	path from the original root. After the
	      chroot has been performed	the now	defunct	portion	of the	config
	      file  path  is  removed  to be able to reread the	config after a
	      reload.

	      All other	file paths (working dir, logfile, roothints,  and  key
	      files)  can  be  specified  in several ways: as an absolute path
	      relative to the new root,	as a relative path to the working  di-
	      rectory,	or  as an absolute path	relative to the	original root.
	      In the last case the path	is adjusted to remove the unused  por-
	      tion.

	      The  pidfile can be either a relative path to the	working	direc-
	      tory, or an absolute path	relative to the	original root.	It  is
	      written  just prior to chroot and	dropping permissions. This al-
	      lows the pidfile to be /var/run/unbound.pid and the chroot to be
	      /var/unbound, for	example.

	      Additionally,  unbound  may  need	to access /dev/random (for en-
	      tropy) from inside the chroot.

	      If given a chroot	is done	to the given directory.	The default is
	      "/var/unbound". If you give "" no	chroot is performed.

       username: _name_
	      If  given,  after	 binding  the  port  the  user	privileges are
	      dropped. Default is "unbound". If	you give username: "" no  user
	      change is	performed.

	      If  this	user  is  not capable of binding the port, reloads (by
	      signal HUP) will still retain the	opened ports.  If  you	change
	      the port number in the config file, and that new port number re-
	      quires privileges, then a	reload will fail; a restart is needed.

       directory: _directory_
	      Sets the working directory for the program. Default is "/var/un-
	      bound".

       logfile:	_filename_
	      If  ""  is given,	logging	goes to	stderr,	or nowhere once	daemo-
	      nized.  The logfile is appended to, in the following format:
	      [seconds since 1970] unbound[pid:tid]: type: message.
	      If this option is	given, the use-syslog  is  option  is  set  to
	      "no".  The logfile is reopened (for append) when the config file
	      is reread, on SIGHUP.

       use-syslog: _yes	or no_
	      Sets unbound to send log messages	to  the	 syslogd,  using  sys-
	      log(3).  The log facility	LOG_DAEMON is used, with identity "un-
	      bound".  The logfile setting is overridden  when	use-syslog  is
	      turned on.  The default is to log	to syslog.

       log-time-ascii: _yes or no_
	      Sets  logfile  lines to use a timestamp in UTC ascii. Default is
	      no, which	prints the seconds since 1970 in brackets.  No	effect
	      if  using	 syslog,  in  that  case  syslog formats the timestamp
	      printed into the log files.

       log-queries: _yes or no_
	      Prints one line per query	to the log, with the log timestamp and
	      IP  address, name, type and class.  Default is no.  Note that it
	      takes time to print these	lines which makes the server (signifi-
	      cantly)  slower.	 Odd  (nonprintable)  characters  in names are
	      printed as '?'.

       pidfile:	_filename_
	      The process id is	written	to  the	 file.	Default	 is  "/var/un-
	      bound/unbound.pid".  So,
	      kill -HUP	`cat /var/unbound/unbound.pid`
	      triggers a reload,
	      kill -QUIT `cat /var/unbound/unbound.pid`
	      gracefully terminates.

       root-hints: _filename_
	      Read  the	 root  hints from this file. Default is	nothing, using
	      builtin hints for	the IN class. The file has the format of  zone
	      files,  with  root  nameserver names and addresses only. The de-
	      fault may	become outdated, when servers change, therefore	it  is
	      good practice to use a root-hints	file.

       hide-identity: _yes or no_
	      If enabled id.server and hostname.bind queries are refused.

       identity: _string_
	      Set  the identity	to report. If set to "", the default, then the
	      hostname of the server is	returned.

       hide-version: _yes or no_
	      If enabled version.server	and version.bind queries are refused.

       version:	_string_
	      Set the version to report. If set	to "", the default,  then  the
	      package version is returned.

       target-fetch-policy: _"list of numbers"_
	      Set  the	target fetch policy used by unbound to determine if it
	      should fetch nameserver target addresses opportunistically.  The
	      policy is	described per dependency depth.

	      The  number  of  values  determines the maximum dependency depth
	      that unbound will	pursue in answering a query.  A	 value	of  -1
	      means to fetch all targets opportunistically for that dependency
	      depth. A value of	0 means	to fetch on demand  only.  A  positive
	      value fetches that many targets opportunistically.

	      Enclose the list between quotes ("") and put spaces between num-
	      bers.  The default is "3 2 1 0 0". Setting all zeroes, "0	0 0  0
	      0"  gives	 behaviour closer to that of BIND 9, while setting "-1
	      -1 -1 -1 -1" gives behaviour rumoured to be closer  to  that  of
	      BIND 8.

       harden-short-bufsize: _yes or no_
	      Very  small  EDNS	buffer sizes from queries are ignored. Default
	      is off, since it is legal	protocol wise to send these,  and  un-
	      bound  tries  to give very small answers to these	queries, where
	      possible.

       harden-large-queries: _yes or no_
	      Very large queries are ignored. Default is off, since it is  le-
	      gal  protocol wise to send these,	and could be necessary for op-
	      eration if TSIG or EDNS payload is very large.

       harden-glue: _yes or no_
	      Will trust glue only if it is within the servers authority.  De-
	      fault is on.

       harden-dnssec-stripped: _yes or no_
	      Require  DNSSEC  data  for trust-anchored	zones, if such data is
	      absent, the zone becomes bogus. If turned	 off,  and  no	DNSSEC
	      data  is	received  (or the DNSKEY data fails to validate), then
	      the zone is made insecure, this behaves like there is  no	 trust
	      anchor.  You  could turn this off	if you are sometimes behind an
	      intrusive	firewall (of some sort)	that removes DNSSEC data  from
	      packets,	or  a  zone  changes  from signed to unsigned to badly
	      signed often. If turned off you run the risk of a	downgrade  at-
	      tack that	disables security for a	zone. Default is on.

       harden-below-nxdomain: _yes or no_
	      From  draft-vixie-dnsext-resimprove, returns nxdomain to queries
	      for a name below another name that is already known to be	 nxdo-
	      main.   DNSSEC  mandates	noerror	 for empty nonterminals, hence
	      this is possible.	 Very old software might return	 nxdomain  for
	      empty  nonterminals  (that usually happen	for reverse IP address
	      lookups),	and thus may be	incompatible with  this.   To  try  to
	      avoid  this  only	 DNSSEC-secure nxdomains are used, because the
	      old software does	not have DNSSEC.  Default is off.

       harden-referral-path: _yes or no_
	      Harden the referral path by performing  additional  queries  for
	      infrastructure data.  Validates the replies if trust anchors are
	      configured and the zones are signed.  This enforces DNSSEC vali-
	      dation  on  nameserver NS	sets and the nameserver	addresses that
	      are encountered on the referral path  to	the  answer.   Default
	      off, because it burdens the authority servers, and it is not RFC
	      standard,	and could lead to performance problems because of  the
	      extra  query  load  that is generated.  Experimental option.  If
	      you enable it  consider  adding  more  numbers  after  the  tar-
	      get-fetch-policy to increase the max depth that is checked to.

       use-caps-for-id:	_yes or	no_
	      Use  0x20-encoded	 random	 bits  in  the query to	foil spoof at-
	      tempts.  This perturbs the  lowercase  and  uppercase  of	 query
	      names  sent  to  authority servers and checks if the reply still
	      has the correct casing.  Disabled	by default.  This  feature  is
	      an experimental implementation of	draft dns-0x20.

       private-address:	_IP address or subnet_
	      Give  IPv4 of IPv6 addresses or classless	subnets. These are ad-
	      dresses on your private network, and are not allowed to  be  re-
	      turned  for  public  internet  names.  Any occurence of such ad-
	      dresses are removed from DNS answers. Additionally,  the	DNSSEC
	      validator	 may  mark  the	 answers  bogus. This protects against
	      so-called	DNS Rebinding, where a user browser is turned  into  a
	      network  proxy,  allowing	 remote	 access	through	the browser to
	      other parts of your private network.  Some names can be  allowed
	      to contain your private addresses, by default all	the local-data
	      that you configured is allowed to, and  you  can	specify	 addi-
	      tional names using private-domain.  No private addresses are en-
	      abled by default.	 We consider to	enable this  for  the  RFC1918
	      private  IP  address  space  by  default in later	releases. That
	      would enable  private  addresses	for  10.0.0.0/8	 172.16.0.0/12
	      192.168.0.0/16  169.254.0.0/16 fd00::/8 and fe80::/10, since the
	      RFC standards say	these addresses	should not be visible  on  the
	      public internet.	Turning	on 127.0.0.0/8 would hinder many spam-
	      blocklists as they use that.

       private-domain: _domain name_
	      Allow this domain, and all its subdomains	to contain private ad-
	      dresses.	 Give multiple times to	allow multiple domain names to
	      contain private addresses. Default is none.

       unwanted-reply-threshold: _number_
	      If set, a	total number of	unwanted replies is kept track	of  in
	      every thread.  When it reaches the threshold, a defensive	action
	      is taken and a warning is	printed	to the log.  The defensive ac-
	      tion  is to clear	the rrset and message caches, hopefully	flush-
	      ing away any poison.  A value of 10 million is  suggested.   De-
	      fault is 0 (turned off).

       do-not-query-address: _IP address_
	      Do  not  query  the  given IP address. Can be IP4	or IP6.	Append
	      /num to indicate a classless delegation  netblock,  for  example
	      like 10.2.3.4/24 or 2001::11/64.

       do-not-query-localhost: _yes or no_
	      If  yes, localhost is added to the do-not-query-address entries,
	      both IP6 ::1 and IP4 127.0.0.1/8.	If no, then localhost  can  be
	      used to send queries to. Default is yes.

       prefetch: _yes or no_
	      If yes, message cache elements are prefetched before they	expire
	      to keep the cache	up to date.  Default is	 no.   Turning	it  on
	      gives about 10 percent more traffic and load on the machine, but
	      popular items do not expire from the cache.

       prefetch-key: _yes or no_
	      If yes, fetch the	DNSKEYs	earlier	 in  the  validation  process,
	      when a DS	record is encountered.	This lowers the	latency	of re-
	      quests.  It does use a little more CPU.  Also if	the  cache  is
	      set to 0,	it is no use. Default is no.

       rrset-roundrobin: _yes or no_
	      If yes, Unbound rotates RRSet order in response (the random num-
	      ber is taken from	the query ID, for speed	 and  thread  safety).
	      Default is no.

       minimal-responses: _yes or no_
	      If  yes,	Unbound	 doesn't  insert authority/additional sections
	      into response messages when those	 sections  are	not  required.
	      This  reduces  response  size  significantly,  and may avoid TCP
	      fallback for some	responses.  This may cause a  slight  speedup.
	      The  default  is no, because the DNS protocol RFCs mandate these
	      sections,	and the	additional content could be of	use  and  save
	      roundtrips for clients.

       module-config: _"module names"_
	      Module  configuration,  a	list of	module names separated by spa-
	      ces, surround the	string with quotes (""). The  modules  can  be
	      validator,  iterator.  Setting this to "iterator"	will result in
	      a	non-validating server.	Setting	this to	 "validator  iterator"
	      will  turn on DNSSEC validation.	The ordering of	the modules is
	      important.  You must also	set trust-anchors for validation to be
	      useful.

       trust-anchor-file: _filename_
	      File  with  trusted  keys	for validation.	Both DS	and DNSKEY en-
	      tries can	appear in the file. The	format	of  the	 file  is  the
	      standard	DNS  Zone file format.	Default	is "", or no trust an-
	      chor file.

       auto-trust-anchor-file: _filename_
	      File with	trust anchor for  one  zone,  which  is	 tracked  with
	      RFC5011  probes.	 The  probes are several times per month, thus
	      the machine must be online frequently.  The initial file can  be
	      one  with	 contents as described in trust-anchor-file.  The file
	      is written to when the anchor is updated,	so  the	 unbound  user
	      must have	write permission.

       trust-anchor: _"Resource	Record"_
	      A	 DS or DNSKEY RR for a key to use for validation. Multiple en-
	      tries can	be given to specify multiple trusted keys, in addition
	      to  the  trust-anchor-files.   The resource record is entered in
	      the same format as 'dig' or 'drill' prints them, the same	format
	      as  in the zone file. Has	to be on a single line,	with ""	around
	      it. A TTL	can be specified for ease of cut and paste, but	is ig-
	      nored.  A	class can be specified,	but class IN is	default.

       trusted-keys-file: _filename_
	      File  with  trusted  keys	 for validation. Specify more than one
	      file with	several	entries, one file per  entry.  Like  trust-an-
	      chor-file	 but  has  a  different	 file format. Format is	BIND-9
	      style format, the	trusted-keys { name flag proto algo "key";  };
	      clauses  are  read.   It	is possible to use wildcards with this
	      statement, the wildcard is expanded on start and on reload.

       dlv-anchor-file:	_filename_
	      File with	trusted	keys for DLV  (DNSSEC  Lookaside  Validation).
	      Both  DS and DNSKEY entries can be used in the file, in the same
	      format as	for trust-anchor-file: statements. Only	one DLV	can be
	      configured,  more	would be slow. The DLV configured is used as a
	      root trusted DLV,	this means that	it  is	a  lookaside  for  the
	      root. Default is "", or no dlv anchor file.

       dlv-anchor: _"Resource Record"_
	      Much  like  trust-anchor,	 this  is  a DLV anchor	with the DS or
	      DNSKEY inline.

       domain-insecure:	_domain	name_
	      Sets domain name to be insecure, DNSSEC chain of	trust  is  ig-
	      nored  towards the domain	name.  So a trust anchor above the do-
	      main name	can not	make the domain	secure with a DS record,  such
	      a	DS record is then ignored.  Also keys from DLV are ignored for
	      the domain.  Can be given	multiple times to specify multiple do-
	      mains that are treated as	if unsigned.  If you set trust anchors
	      for the domain they override this	setting	(and the domain	is se-
	      cured).

	      This  can	 be useful if you want to make sure a trust anchor for
	      external lookups does not	affect an (unsigned) internal  domain.
	      A	 DS  record externally can create validation failures for that
	      internal domain.

       val-override-date: _rrsig-style date spec_
	      Default is "" or "0", which disables this	debugging feature.  If
	      enabled by giving	a RRSIG	style date, that date is used for ver-
	      ifying RRSIG inception and expiration dates, instead of the cur-
	      rent  date.  Do  not set this unless you are debugging signature
	      inception	and expiration.	The value -1 ignores  the  date	 alto-
	      gether, useful for some special applications.

       val-sig-skew-min: _seconds_
	      Minimum  number  of  seconds of clock skew to apply to validated
	      signatures.  A value of 10% of the signature  lifetime  (expira-
	      tion  -  inception) is used, capped by this setting.  Default is
	      3600 (1 hour) which allows  for  daylight	 savings  differences.
	      Lower  this value	for more strict	checking of short lived	signa-
	      tures.

       val-sig-skew-max: _seconds_
	      Maximum number of	seconds	of clock skew to  apply	 to  validated
	      signatures.   A  value of	10% of the signature lifetime (expira-
	      tion - inception)	is used, capped	by this	setting.   Default  is
	      86400  (24  hours) which allows for timezone setting problems in
	      stable domains.  Setting both min	and max	very low disables  the
	      clock skew allowances.  Setting both min and max very high makes
	      the validator check the signature	timestamps less	strictly.

       val-bogus-ttl: _number_
	      The time to live for bogus data. This is data  that  has	failed
	      validation;  due	to invalid signatures or other checks. The TTL
	      from that	data cannot be trusted,	and this  value	 is  used  in-
	      stead.  The  value is in seconds,	default	60.  The time interval
	      prevents repeated	revalidation of	bogus data.

       val-clean-additional: _yes or no_
	      Instruct the validator to	remove data from the  additional  sec-
	      tion  of	secure messages	that are not signed properly. Messages
	      that are insecure, bogus,	indeterminate or unchecked are not af-
	      fected.  Default	is  yes. Use this setting to protect the users
	      that rely	on this	validator for authentication from protentially
	      bad data in the additional section.

       val-log-level: _number_
	      Have  the	 validator  print validation failures to the log.  Re-
	      gardless of the verbosity	setting.  Default is 0,	 off.	At  1,
	      for  every  user query that fails	a line is printed to the logs.
	      This way you can monitor what happens with  validation.	Use  a
	      diagnosis	tool, such as dig or drill, to find out	why validation
	      is failing for these queries.  At	2, not	only  the  query  that
	      failed is	printed	but also the reason why	unbound	thought	it was
	      wrong and	which server sent the faulty data.

       val-permissive-mode: _yes or no_
	      Instruct the validator to	mark bogus messages as	indeterminate.
	      The  security  checks  are performed, but	if the result is bogus
	      (failed security), the reply is not  withheld  from  the	client
	      with  SERVFAIL as	usual. The client receives the bogus data. For
	      messages that are	found to be  secure  the  AD  bit  is  set  in
	      replies.	Also logging is	performed as for full validation.  The
	      default value is "no".

       ignore-cd-flag: _yes or no_
	      Instruct unbound to ignore the CD	flag from clients  and	refuse
	      to  return  bogus	 answers to them.  Thus, the CD	(Checking Dis-
	      abled) flag does not disable checking any	more.  This is	useful
	      if  legacy (w2008) servers that set the CD flag but cannot vali-
	      date DNSSEC themselves are the clients, and  then	 unbound  pro-
	      vides them with DNSSEC protection.  The default value is "no".

       val-nsec3-keysize-iterations: _"list of values"_
	      List of keysize and iteration count values, separated by spaces,
	      surrounded by quotes. Default is "1024 150 2048 500 4096	2500".
	      This determines the maximum allowed NSEC3	iteration count	before
	      a	message	is simply marked insecure instead  of  performing  the
	      many hashing iterations. The list	must be	in ascending order and
	      have at least one	entry. If you set it to	"1024 65535" there  is
	      no  restriction  to  NSEC3 iteration values.  This table must be
	      kept short; a very long list could cause slower operation.

       add-holddown: _seconds_
	      Instruct the auto-trust-anchor-file probe	mechanism for  RFC5011
	      autotrust	 updates to add	new trust anchors only after they have
	      been visible for this time.  Default is 30 days as per the RFC.

       del-holddown: _seconds_
	      Instruct the auto-trust-anchor-file probe	mechanism for  RFC5011
	      autotrust	 updates  to  remove  revoked trust anchors after they
	      have been	kept in	the revoked list for this long.	 Default is 30
	      days as per the RFC.

       keep-missing: _seconds_
	      Instruct	the auto-trust-anchor-file probe mechanism for RFC5011
	      autotrust	updates	to remove missing  trust  anchors  after  they
	      have  been  unseen for this long.	 This cleans up	the state file
	      if the target zone does not perform trust	anchor revocation,  so
	      this makes the auto probe	mechanism work with zones that perform
	      regular (non-5011) rollovers.  The default  is  366  days.   The
	      value 0 does not remove missing anchors, as per the RFC.

       key-cache-size: _number_
	      Number  of  bytes	size of	the key	cache. Default is 4 megabytes.
	      A	plain number is	in bytes, append 'k', 'm'  or  'g'  for	 kilo-
	      bytes, megabytes or gigabytes (1024*1024 bytes in	a megabyte).

       key-cache-slabs:	_number_
	      Number  of  slabs	in the key cache. Slabs	reduce lock contention
	      by threads.  Must	be set to a power of 2.	Setting	(close)	to the
	      number of	cpus is	a reasonable guess.

       neg-cache-size: _number_
	      Number  of  bytes	size of	the aggressive negative	cache. Default
	      is 1 megabyte.  A	plain number is	in bytes, append 'k',  'm'  or
	      'g'  for kilobytes, megabytes or gigabytes (1024*1024 bytes in a
	      megabyte).

       unblock-lan-zones: _yesno_
	      Default is disabled.   If	 enabled,  then	 for  private  address
	      space,  the reverse lookups are no longer	filtered.  This	allows
	      unbound when running as dns service on a host where it  provides
	      service  for  that  host,	 to put	out all	of the queries for the
	      'lan' upstream.  When enabled, only localhost, 127.0.0.1 reverse
	      and  ::1	reverse	zones are configured with default local	zones.
	      Disable the option when unbound is running as a (DHCP-) DNS net-
	      work resolver for	a group	of machines, where such	lookups	should
	      be filtered (RFC compliance), this  also	stops  potential  data
	      leakage about the	local network to the upstream DNS servers.

       local-zone: _zone_ _type_
	      Configure	 a  local zone.	The type determines the	answer to give
	      if there is no  match  from  local-data.	The  types  are	 deny,
	      refuse,  static, transparent, redirect, nodefault, typetranspar-
	      ent, and are explained below. After that	the  default  settings
	      are  listed.  Use	local-data: to enter data into the local zone.
	      Answers for local	zones are authoritative	DNS  answers.  By  de-
	      fault the	zones are class	IN.

	      If you need more complicated authoritative data, with referrals,
	      wildcards, CNAME/DNAME support, or DNSSEC	authoritative service,
	      setup  a	stub-zone  for it as detailed in the stub zone section
	      below.

	    deny Do not	send an	answer,	drop the query.	 If there is  a	 match
		 from local data, the query is answered.

	    refuse
		 Send an error message reply, with rcode REFUSED.  If there is
		 a match from local data, the query is answered.

	    static
		 If there is a match from local	data, the query	 is  answered.
		 Otherwise,  the  query	 is  answered with nodata or nxdomain.
		 For a negative	answer a SOA is	 included  in  the  answer  if
		 present as local-data for the zone apex domain.

	    transparent
		 If  there  is a match from local data,	the query is answered.
		 Otherwise if the query	has a different	name, the query	is re-
		 solved	 normally.  If the query is for	a name given in	local-
		 data but no such type of data is given	in localdata,  then  a
		 noerror nodata	answer is returned.  If	no local-zone is given
		 local-data causes a transparent zone to  be  created  by  de-
		 fault.

	    typetransparent
		 If  there  is a match from local data,	the query is answered.
		 If the	query is for a different name, or for  the  same  name
		 but  for  a  different	 type, the query is resolved normally.
		 So, similar to	transparent but	types that are not  listed  in
		 local data are	resolved normally, so if an A record is	in the
		 local data that does  not  cause  a  nodata  reply  for  AAAA
		 queries.

	    redirect
		 The  query is answered	from the local data for	the zone name.
		 There may be no local data beneath the	zone name.   This  an-
		 swers	queries	 for  the zone,	and all	subdomains of the zone
		 with the local	data for the zone.  It can be used to redirect
		 a  domain  to	return	a  different address record to the end
		 user,	with  local-zone:  "example.com."  redirect  and   lo-
		 cal-data:  "example.com.  A  127.0.0.1" queries for www.exam-
		 ple.com and www.foo.example.com are redirected, so that users
		 with  web  browsers  cannot  access  sites  with suffix exam-
		 ple.com.

	    nodefault
		 Used to turn off default contents for AS112 zones. The	 other
		 types also turn off default contents for the zone. The	'node-
		 fault'	option has no other effect than	 turning  off  default
		 contents for the given	zone.

       The  default  zones  are	 localhost, reverse 127.0.0.1 and ::1, and the
       AS112 zones. The	AS112 zones are	reverse	DNS zones for private use  and
       reserved	IP addresses for which the servers on the internet cannot pro-
       vide correct answers. They are configured by default to	give  nxdomain
       (no  reverse  information)  answers.  The defaults can be turned	off by
       specifying your own local-zone of that name, or using  the  'nodefault'
       type. Below is a	list of	the default zone contents.

	    localhost
		 The  IP4  and	IP6 localhost information is given. NS and SOA
		 records are provided for completeness and to satisfy some DNS
		 update	tools. Default content:
		 local-zone: "localhost." static
		 local-data: "localhost. 10800 IN NS localhost."
		 local-data: "localhost. 10800 IN
		     SOA localhost. nobody.invalid. 1 3600 1200	604800 10800"
		 local-data: "localhost. 10800 IN A 127.0.0.1"
		 local-data: "localhost. 10800 IN AAAA ::1"

	    reverse IPv4 loopback
		 Default content:
		 local-zone: "127.in-addr.arpa." static
		 local-data: "127.in-addr.arpa.	10800 IN NS localhost."
		 local-data: "127.in-addr.arpa.	10800 IN
		     SOA localhost. nobody.invalid. 1 3600 1200	604800 10800"
		 local-data: "1.0.0.127.in-addr.arpa. 10800 IN
		     PTR localhost."

	    reverse IPv6 loopback
		 Default content:
		 local-zone: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
		     0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa." static
		 local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
		     0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
		     NS	localhost."
		 local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
		     0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
		     SOA localhost. nobody.invalid. 1 3600 1200	604800 10800"
		 local-data: "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
		     0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa. 10800 IN
		     PTR localhost."

	    reverse RFC1918 local use zones
		 Reverse  data	for zones 10.in-addr.arpa, 16.172.in-addr.arpa
		 to  31.172.in-addr.arpa,   168.192.in-addr.arpa.    The   lo-
		 cal-zone: is set static and as	local-data: SOA	and NS records
		 are provided.

	    reverse RFC3330 IP4	this, link-local, testnet and broadcast
		 Reverse data for zones	0.in-addr.arpa,	 254.169.in-addr.arpa,
		 2.0.192.in-addr.arpa  (TEST  NET  1), 100.51.198.in-addr.arpa
		 (TEST	NET   2),   113.0.203.in-addr.arpa   (TEST   NET   3),
		 255.255.255.255.in-addr.arpa.

	    reverse RFC4291 IP6	unspecified
		 Reverse data for zone
		 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.
		 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.

	    reverse RFC4193 IPv6 Locally Assigned Local	Addresses
		 Reverse data for zone D.F.ip6.arpa.

	    reverse RFC4291 IPv6 Link Local Addresses
		 Reverse data for zones	8.E.F.ip6.arpa to B.E.F.ip6.arpa.

	    reverse IPv6 Example Prefix
		 Reverse  data for zone	8.B.D.0.1.0.0.2.ip6.arpa. This zone is
		 used for tutorials and	examples. You can remove the block  on
		 this zone with:
		   local-zone: 8.B.D.0.1.0.0.2.ip6.arpa. nodefault
		 You can also selectively unblock a part of the	zone by	making
		 that part transparent with a local-zone statement.  This also
		 works with the	other default zones.

       local-data: "_resource record string_"
	    Configure  local data, which is served in reply to queries for it.
	    The	query has to match exactly unless you configure	the local-zone
	    as	redirect.  If  not matched exactly, the	local-zone type	deter-
	    mines further processing. If local-data is configured that is  not
	    a  subdomain  of a local-zone, a transparent local-zone is config-
	    ured.  For record types such as TXT, use single quotes, as in  lo-
	    cal-data: 'example.	TXT "text"'.

	    If	you  need more complicated authoritative data, with referrals,
	    wildcards, CNAME/DNAME support, or DNSSEC  authoritative  service,
	    setup  a stub-zone for it as detailed in the stub zone section be-
	    low.

       local-data-ptr: "IPaddr name"
	    Configure local data shorthand for a PTR record with the  reversed
	    IPv4  or  IPv6  address and	the host name.	For example "192.0.2.4
	    www.example.com".  TTL can be  inserted  like  this:  "2001:DB8::4
	    7200 www.example.com"

   Remote Control Options
       In  the remote-control: clause are the declarations for the remote con-
       trol facility.  If this is enabled, the unbound-control(8) utility  can
       be  used	 to  send  commands to the running unbound server.  The	server
       uses these clauses to setup SSLv3 / TLSv1 security for the  connection.
       The  unbound-control(8)	utility	 also reads the	remote-control section
       for options.  To	setup the correct self-signed certificates use the un-
       bound-control-setup(8) utility.

       control-enable: _yes or no_
	    The	 option	is used	to enable remote control, default is "no".  If
	    turned off,	the server does	not listen for control commands.

       control-interface: <ip address>
	    Give IPv4 or IPv6 addresses	to listen on for control commands.  By
	    default localhost (127.0.0.1 and ::1) is listened to.  Use 0.0.0.0
	    and	::0 to listen to all interfaces.

       control-port: <port number>
	    The	port number to listen on  for  control	commands,  default  is
	    8953.   If	you change this	port number, and permissions have been
	    dropped, a reload is not sufficient	to open	the  port  again,  you
	    must then restart.

       server-key-file:	<private key file>
	    Path  to  the  server  private key,	by default unbound_server.key.
	    This file is generated by the unbound-control-setup	utility.  This
	    file is used by the	unbound	server,	but not	by unbound-control.

       server-cert-file: <certificate file.pem>
	    Path  to  the  server  self	 signed	 certificate,  by  default un-
	    bound_server.pem.  This file  is  generated	 by  the  unbound-con-
	    trol-setup	utility.  This file is used by the unbound server, and
	    also by unbound-control.

       control-key-file: <private key file>
	    Path to the	control	client private key,  by	 default  unbound_con-
	    trol.key.	This  file  is	generated by the unbound-control-setup
	    utility.  This file	is used	by unbound-control.

       control-cert-file: <certificate file.pem>
	    Path to the	control	client certificate,  by	 default  unbound_con-
	    trol.pem.	This certificate has to	be signed with the server cer-
	    tificate.  This file is  generated	by  the	 unbound-control-setup
	    utility.  This file	is used	by unbound-control.

   Stub	Zone Options
       There may be multiple stub-zone:	clauses. Each with a name: and zero or
       more hostnames or IP addresses.	For the	stub zone this list  of	 name-
       servers	is used. Class IN is assumed.  The servers should be authority
       servers,	not recursors; unbound performs	the recursive  processing  it-
       self for	stub zones.

       The stub	zone can be used to configure authoritative data to be used by
       the resolver that cannot	be accessed using the public internet servers.
       This  is	 useful	 for company-local data	or private zones. Setup	an au-
       thoritative server on a different host (or  different  port).  Enter  a
       config  entry  for unbound with stub-addr: <ip address of host[@port]>.
       The unbound resolver can	then access the	data, without referring	to the
       public internet for it.

       This  setup  allows DNSSEC signed zones to be served by that authorita-
       tive server, in which case a trusted key	entry with the public key  can
       be  put in config, so that unbound can validate the data	and set	the AD
       bit on replies for the private zone (authoritative servers do  not  set
       the AD bit).  This setup	makes unbound capable of answering queries for
       the private zone, and can even set the AD bit ('authentic'), but	the AA
       ('authoritative') bit is	not set	on these replies.

       name: _domain name_
	      Name of the stub zone.

       stub-host: _domain name_
	      Name  of	stub  zone nameserver. Is itself resolved before it is
	      used.

       stub-addr: _IP address_
	      IP address of stub zone nameserver. Can be IP 4 or IP 6.	To use
	      a	nondefault port	for DNS	communication append '@' with the port
	      number.

       stub-prime: _yes	or no_
	      This option is by	default	off.  If enabled it  performs  NS  set
	      priming,	which  is similar to root hints, where it starts using
	      the list of nameservers currently	published by the zone.	 Thus,
	      if  the  hint list is slightly outdated, the resolver picks up a
	      correct list online.

       stub-first: _yes	or no_
	      If enabled, a query is attempted without the stub	clause	if  it
	      fails.   The  data  could	not be retrieved and would have	caused
	      SERVFAIL because the servers  are	 unreachable,  instead	it  is
	      tried without this clause.  The default is no.

   Forward Zone	Options
       There may be multiple forward-zone: clauses. Each with a	name: and zero
       or more hostnames or IP addresses.  For the forward zone	this  list  of
       nameservers  is	used  to forward the queries to. The servers listed as
       forward-host: and forward-addr: have to handle  further	recursion  for
       the  query.   Thus,  those  servers  are	not authority servers, but are
       (just like unbound is) recursive	servers	too; unbound does not  perform
       recursion itself	for the	forward	zone, it lets the remote server	do it.
       Class IN	is assumed.  A forward-zone entry with name  "."  and  a  for-
       ward-addr  target will forward all queries to that other	server (unless
       it can answer from the cache).

       name: _domain name_
	      Name of the forward zone.

       forward-host: _domain name_
	      Name of server to	forward	to. Is itself resolved	before	it  is
	      used.

       forward-addr: _IP address_
	      IP address of server to forward to. Can be IP 4 or IP 6.	To use
	      a	nondefault port	for DNS	communication append '@' with the port
	      number.

       forward-first: _yes or no_
	      If  enabled,  a query is attempted without the forward clause if
	      it fails.	 The data could	not be retrieved and would have	caused
	      SERVFAIL	because	 the  servers  are  unreachable, instead it is
	      tried without this clause.  The default is no.

   Python Module Options
       The python: clause gives	the settings for the python(1) script  module.
       This module acts	like the iterator and validator	modules	do, on queries
       and answers.  To	enable the script module it has	to  be	compiled  into
       the  daemon,  and the word "python" has to be put in the	module-config:
       option (usually first, or between the validator and iterator).

       python-script: _python file_
	      The script file to load.

MEMORY CONTROL EXAMPLE
       In the example config settings below memory usage is reduced. Some ser-
       vice  levels are	lower, notable very large data and a high TCP load are
       no longer supported. Very large data and	high TCP loads are exceptional
       for the DNS.  DNSSEC validation is enabled, just	add trust anchors.  If
       you do not have to worry	about programs using more than 3 Mb of memory,
       the below example is not	for you. Use the defaults to receive full ser-
       vice, which on BSD-32bit	tops out at 30-40 Mb after heavy usage.

       # example settings that reduce memory usage
       server:
	    num-threads: 1
	    outgoing-num-tcp: 1	# this limits TCP service, uses	less buffers.
	    incoming-num-tcp: 1
	    outgoing-range: 60	# uses less memory, but	less performance.
	    msg-buffer-size: 8192   # note this	limits service,	'no huge stuff'.
	    msg-cache-size: 100k
	    msg-cache-slabs: 1
	    rrset-cache-size: 100k
	    rrset-cache-slabs: 1
	    infra-cache-numhosts: 200
	    infra-cache-slabs: 1
	    key-cache-size: 100k
	    key-cache-slabs: 1
	    neg-cache-size: 10k
	    num-queries-per-thread: 30
	    target-fetch-policy: "2 1 0	0 0 0"
	    harden-large-queries: "yes"
	    harden-short-bufsize: "yes"

FILES
       /var/unbound
	      default unbound working directory.

       /var/unbound
	      default chroot(2)	location.

       /var/unbound/unbound.conf
	      unbound configuration file.

       /var/unbound/unbound.pid
	      default unbound pidfile with process ID of the running daemon.

       unbound.log
	      unbound log file.	default	is to log to syslog(3).

SEE ALSO
       unbound(8), unbound-checkconf(8).

AUTHORS
       Unbound was written by NLnet Labs. Please see CREDITS file in the  dis-
       tribution for further details.

NLnet Labs			 Mar 12, 2014		       unbound.conf(5)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | FILE FORMAT | MEMORY CONTROL EXAMPLE | FILES | SEE ALSO | AUTHORS

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