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unbound.conf(5)			unbound	1.5.10		       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	or  is	specified before the include statement with directory:
       dir.  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 or ip6 netblock_
	      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.

	      If  an  IPv6 netblock is specified instead of an individual IPv6
	      address, outgoing	UDP queries will use a randomised  source  ad-
	      dress  taken from	the netblock to	counter	spoofing. Requires the
	      IPv6 netblock to be routed to the	host running unbound, and  re-
	      quires  OS  support  for unprivileged non-local binds (currently
	      only supported on	Linux).	Several	 netblocks  may	 be  specified
	      with  multiple  outgoing-interface:  options, but	do not specify
	      both an individual IPv6 address and an  IPv6  netblock,  or  the
	      randomisation will be compromised.  Consider combining with pre-
	      fer-ip6: yes to increase the likelihood of IPv6 nameservers  be-
	      ing  selected for	queries.  On Linux you need these two commands
	      to be able to use	the freebind socket option to receive  traffic
	      for  the ip6 netblock: ip	-6 addr	add mynetblock/64 dev lo && ip
	      -6 route add local mynetblock/64 dev lo

       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 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.  For larger	installations increas-
	      ing this value is	a good idea.

       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. For larger installations increasing this
	      value is a good idea.

       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.  On Linux it	 is  supported
	      in  kernels  >= 3.9.  On other systems, FreeBSD, OSX it may also
	      work.  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.

       ip-transparent: _yes or no_
	      If  yes,	then use IP_TRANSPARENT	socket option on sockets where
	      unbound is listening for incoming	traffic.  Default no.	Allows
	      you  to bind to non-local	interfaces.  For example for non-exis-
	      tant IP addresses	that are going to exist	later  on,  with  host
	      failover configuration.  This is a lot like interface-automatic,
	      but that one services all	interfaces and with  this  option  you
	      can  select  which  (future) interfaces unbound provides service
	      on.  This	option needs unbound to	be started with	 root  permis-
	      sions  on	 some  systems.	 The option uses IP_BINDANY on FreeBSD
	      systems.

       ip-freebind: _yes or no_
	      If yes, then use IP_FREEBIND socket option on sockets where  un-
	      bound is listening to incoming traffic.  Default no.  Allows you
	      to bind to IP addresses that are nonlocal	or do not exist,  like
	      when  the	 network interface or IP address is down.  Exists only
	      on Linux,	where the similar ip-transparent option	is also	avail-
	      able.

       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 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.

       cache-max-negative-ttl: _seconds_
	      Time to live maximum for negative	responses, these have a	SOA in
	      the authority section that is limited in time.  Default is 3600.

       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.

       infra-cache-min-rtt: _msec_
	      Lower limit for dynamic retransmit timeout calculation in	infra-
	      structure	cache. Default is 50 milliseconds. Increase this value
	      if using forwarders needing more time to do recursive name reso-
	      lution.

       define-tag: _"list of tags"_
	      Define the tags that can be used with local-zone and access-con-
	      trol.  Enclose the list between quotes ("") and put  spaces  be-
	      tween tags.

       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.
	      With  this option	you can	disable	the ipv6 transport for sending
	      DNS traffic, it does not impact the contents of the DNS traffic,
	      which may	have ip4 and ip6 addresses in it.

       prefer-ip6: _yes	or no_
	      If enabled, prefer IPv6 transport	for sending DNS	queries	to in-
	      ternet nameservers. Default is no.

       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-mss:	_number_
	      Maximum segment size (MSS) of TCP	socket on which	the server re-
	      sponds to	queries. Value lower than common MSS on	Ethernet (1220
	      for example) will	address	path MTU problem.  Note	that  not  all
	      platform	supports  socket  option to set	MSS (TCP_MAXSEG).  De-
	      fault is system default MSS determined by	interface MTU and  ne-
	      gotiation	between	server and client.

       outgoing-tcp-mss: _number_
	      Maximum  segment	size  (MSS) of TCP socket for outgoing queries
	      (from Unbound to other servers). Value lower than	common MSS  on
	      Ethernet (1220 for example) will address path MTU	problem.  Note
	      that  not	 all  platform	supports  socket  option  to  set  MSS
	      (TCP_MAXSEG).   Default  is system default MSS determined	by in-
	      terface MTU and negotiation between Unbound and other servers.

       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
	      853, 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  most	specific netblock match	is used, if none match deny is
	      used.

	      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.

       access-control-tag: _IP netblock_ _"list	of tags"_
	      Assign  tags  to access-control elements.	Clients	using this ac-
	      cess control element use localzones that are tagged with one  of
	      these  tags.  Tags must be defined in define-tags.  Enclose list
	      of tags in quotes	("") and  put  spaces  between	tags.  If  ac-
	      cess-control-tag is configured for a netblock that does not have
	      an access-control, an access-control element with	 action	 allow
	      is configured for	this netblock.

       access-control-tag-action: _IP netblock_	_tag_ _action_
	      Set  action for particular tag for given access control element.
	      If you have multiple tag values, the tag used to lookup the  ac-
	      tion  is	the first tag match between access-control-tag and lo-
	      cal-zone-tag where "first" comes from the	order of  the  define-
	      tag values.

       access-control-tag-data:	_IP netblock_ _tag_ _"resource record string"_
	      Set  redirect  data  for particular tag for given	access control
	      element.

       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".  On Windows the string "%EXECUTABLE%" tries to change to
	      the directory that  unbound.exe  resides	in.   If  you  give  a
	      server:  directory:  dir	before	include:  file statements then
	      those includes can be relative to	the working directory.

       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 -TERM `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.  Currently,
	      draft-ietf-dnsop-nxdomain-cut promotes this technique.

       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.

       harden-algo-downgrade: _yes or no_
	      Harden  against algorithm	downgrade when multiple	algorithms are
	      advertised in the	DS record.  If no, allows  the	weakest	 algo-
	      rithm  to	 validate the zone.  Default is	no.  Zone signers must
	      produce zones that allow this feature  to	 work,	but  sometimes
	      they  do not, and	turning	this option off	avoids that validation
	      failure.

       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.

       caps-whitelist: _domain_
	      Whitelist	the domain so that it  does  not  receive  caps-for-id
	      perturbed	 queries.   For	 domains  that do not support 0x20 and
	      also fail	with fallback because they keep	sending	different  an-
	      swers,  like  some load balancers.  Can be given multiple	times,
	      for different domains.

       qname-minimisation: _yes	or no_
	      Send minimum amount of information to upstream  servers  to  en-
	      hance  privacy.	Only sent minimum required labels of the QNAME
	      and set QTYPE to NS when possible. Best  effort  approach,  full
	      QNAME and	original QTYPE will be sent when upstream replies with
	      a	RCODE other than NOERROR. Default is off.

       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 occurrence	 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.	  Adding  ::ffff:0:0/96	 stops
	      IPv4-mapped IPv6 addresses from bypassing	the filter.

       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.

       disable-dnssec-lame-check: _yes or no_
	      If  true,	 disables  the	DNSSEC lameness	check in the iterator.
	      This check sees if RRSIGs	are present in the answer, when	dnssec
	      is  expected,  and retries another authority if RRSIGs are unex-
	      pectedly missing.	 The  validator	 will  insist  in  RRSIGs  for
	      DNSSEC signed domains regardless of this setting,	if a trust an-
	      chor is loaded.

       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.  Write permission to the  file,  but
	      also  to	the  directory	it  is in (to create a temporary file,
	      which is necessary to deal with filesystem full events).

       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_
	      This option was used during early	days DNSSEC deployment when no
	      parent-side  DS  record  registrations  were  easily  available.
	      Nowadays,	it is best to have DS records registered with the par-
	      ent zone (many top level zones are signed).  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 is going to  be  decommissioned.
	      Please do	not use	it any more.

       dlv-anchor: _"Resource Record"_
	      Much  like  trust-anchor,	 this  is  a DLV anchor	with the DS or
	      DNSKEY inline.  DLV is going to be  decommissioned.   Please  do
	      not use it any more.

       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 potentially
	      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.

       permit-small-holddown: _yes or no_
	      Debug option that	allows the autotrust 5011 rollover  timers  to
	      assume very small	values.	 Default is no.

       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.

       insecure-lan-zones: _yesno_
	      Default  is  disabled.  If enabled, then reverse lookups in pri-
	      vate address space are not validated.  This is usually  required
	      whenever unblock-lan-zones is used.

       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, inform, inform_deny,	always_transparent, always_refuse, al-
	      ways_nxdomain,  and  are explained below.	After that the default
	      settings are listed. Use local-data: to enter data into the  lo-
	      cal zone.	Answers	for local zones	are authoritative DNS answers.
	      By default 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.

	    inform
		 The  query  is	 answered  normally.   The  client  IP address
		 (@portnumber) is printed to the logfile.  The log message is:
		 timestamp,  unbound-pid, info:	zonename inform	IP@port	query-
		 name type class.  This	option can be used for normal  resolu-
		 tion,	but machines looking up	infected names are logged, eg.
		 to run	antivirus on them.

	    inform_deny
		 The query is dropped, like 'deny', and	logged,	like 'inform'.
		 Ie. find infected machines without answering the queries.

	    always_transparent
		 Like  transparent,  but  ignores local	data and resolves nor-
		 mally.

	    always_refuse
		 Like refuse, but ignores local	data and refuses the query.

	    always_nxdomain
		 Like static, but ignores local	data and returns nxdomain  for
		 the query.

	    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.  Use nodefault if	 you  use  ex-
		 actly	that zone, if you want to use a	subzone, use transpar-
		 ent.

       The default zones are localhost,	reverse	127.0.0.1 and ::1,  the	 onion
       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  provide 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	'node-
       fault' 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."

	    onion (RFC 7686)
		 Default content:
		 local-zone: "onion." static
		 local-data: "onion. 10800 IN NS localhost."
		 local-data: "onion. 10800 IN
		     SOA localhost. nobody.invalid. 1 3600 1200	604800 10800"

	    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.	And  from  64.100.in-addr.arpa
		 to 127.100.in-addr.arpa (Shared Address Space).

	    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"

       local-zone-tag: _zone_ _"list of	tags"_
	    Assign  tags to localzones.	Tagged localzones will only be applied
	    when the used access-control element has a matching	tag. Tags must
	    be	defined	 in  define-tags.  Enclose list	of tags	in quotes ("")
	    and	put spaces between tags.

       local-zone-override: _zone_ _IP netblock_ _type_
	    Override the localzone type	for queries  from  addresses  matching
	    netblock.  Use this	localzone type,	regardless the type configured
	    for	the local-zone (both tagged and	untagged) and  regardless  the
	    type configured using access-control-tag-action.

       ratelimit: _number or 0_
	    Enable  ratelimiting  of queries sent to nameserver	for performing
	    recursion.	If 0, the default, it is disabled.  This option	is ex-
	    perimental	at  this time.	The ratelimit is in queries per	second
	    that are allowed.  More queries are	 turned	 away  with  an	 error
	    (servfail).	  This stops recursive floods, eg. random query	names,
	    but	not spoofed reflection floods.	Cached responses are not rate-
	    limited  by	 this setting.	The zone of the	query is determined by
	    examining the nameservers for it, the zone name is	used  to  keep
	    track  of  the rate.  For example, 1000 may	be a suitable value to
	    stop the server from being overloaded with random names, and keeps
	    unbound from sending traffic to the	nameservers for	those zones.

       ratelimit-size: _memory size_
	    Give  the  size of the data	structure in which the current ongoing
	    rates are kept track in.  Default 4m.  In bytes  or	 use  m(mega),
	    k(kilo),  g(giga).	The ratelimit structure	is small, so this data
	    structure likely does not need to be large.

       ratelimit-slabs:	_number_
	    Give power of 2 number of slabs, this is used to reduce lock  con-
	    tention  in	 the  ratelimit	tracking data structure.  Close	to the
	    number of cpus is a	fairly good setting.

       ratelimit-factor: _number_
	    Set	the amount of queries to rate limit  when  the	limit  is  ex-
	    ceeded.   If  set  to 0, all queries are dropped for domains where
	    the	limit is exceeded.  If set to another value, 1 in that	number
	    is	allowed	 through  to  complete.	  Default is 10, allowing 1/10
	    traffic to flow normally.  This can	make ordinary queries complete
	    (if	repeatedly queried for), and enter the cache, whilst also mit-
	    igating the	traffic	flow by	the factor given.

       ratelimit-for-domain: _domain_ _number qps_
	    Override the global	ratelimit for an exact match domain name  with
	    the	 listed	 number.   You	can give this for any number of	names.
	    For	example, for a top-level-domain	you may	want to	have a	higher
	    limit than other names.

       ratelimit-below-domain: _domain_	_number	qps_
	    Override  the global ratelimit for a domain	name that ends in this
	    name.  You can give	this multiple times, it	then describes differ-
	    ent	 settings  in  different  parts	of the namespace.  The closest
	    matching suffix is used to determine the qps limit.	 The rate  for
	    the	  exact	 matching  domain  name	 is  not  changed,  use	 rate-
	    limit-for-domain to	set that, you might want to use	different set-
	    tings for a	top-level-domain and subdomains.

   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 or path_
	    Give IPv4 or IPv6 addresses	or local socket	path 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.  If
	    you	 change	 this  and  permissions	 have  been  dropped, you must
	    restart the	server for the change to take effect.

       control-port: _port number_
	    The	port number to listen on for IPv4 or IPv6 control  interfaces,
	    default  is	 8953.	 If  you change	this and permissions have been
	    dropped, you must restart the server for the change	 to  take  ef-
	    fect.

       control-use-cert: _yes or no_
	    Whether  to	 require certificate authentication of control connec-
	    tions.  The	default	is "yes".  This	should not be  changed	unless
	    there  are	other  mechanisms  in place to prevent untrusted users
	    from accessing the remote control interface.

       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.

       Consider	adding server: statements for  domain-insecure:	 and  for  lo-
       cal-zone:  name	nodefault for the zone if it is	a locally served zone.
       The insecure clause stops DNSSEC	from invalidating the zone.  The local
       zone nodefault (or transparent) clause makes the	(reverse-) zone	bypass
       unbound's filtering of RFC1918 zones.

       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.

   DNS64 Module	Options
       The  dns64  module must be configured in	the module-config: "dns64 val-
       idator iterator"	directive and be compiled into the daemon  to  be  en-
       abled.  These settings go in the	server:	section.

       dns64-prefix: _IPv6 prefix_
	      This  sets  the  DNS64  prefix to	use to synthesize AAAA records
	      with.  It	must  be  /96  or  shorter.   The  default  prefix  is
	      64:ff9b::/96.

       dns64-synthall: _yes or no_
	      Debug  option,  default  no.   If	 enabled,  synthesize all AAAA
	      records despite the presence of actual AAAA records.

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			 Sep 27, 2016		       unbound.conf(5)

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

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