Provided by: unbound_1.3.4-1ubuntu2_i386 bug

NAME

       unbound.conf - Unbound configuration file.

SYNOPSIS

       unbound.conf

DESCRIPTION

       unbound.conf  is  used  to  configure  unbound(8).  The file format has
       attributes 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
       ignored 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/unbound.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
       extensive 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
       anywhere, and takes a  single  filename  as  an  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 included files works, relative pathnames for the included names
       work  if  the  directory  where  the  daemon  is  started  equals   its
       chroot/working directory.

   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
              commandline, 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.

       statistics-cumulative: <yes or no>
              If  enabled,  statistics  are cumulative since starting unbound,
              without clearing  the  statistics  counters  after  logging  the
              statistics. Default is no.

       extended-statistics: <yes or no>
              If    enabled,    extended    statistics    are   printed   from
              unbound-control(8).  Default is off, because  keeping  track  of
              more statistics takes time.

       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>
              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
              localhost.   The  interfaces  are  not changed on a reload (kill
              -HUP) but only on restart.

       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
              IPv6 (and  its  socket  options)  and  IPv4  (and  have  source-
              interface 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
              interfaces. If none are given the default (all) is used. You can
              specify     the    same    interfaces    in    interface:    and
              outgoing-interface: 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 is 256. Larger
              numbers need extra resources from the operating system.

       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
              increases 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
              permitted  ports  and subtracting the avoided ports from the set
              of allowed ports.  The  processing  starts  with  the  non  IANA
              allocated 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
              authoritative 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.

       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
              reduced 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
              contention  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
              simultaneously.  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 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
              allowed time.  This protects against denial of service  by  slow
              queries or high query rates.  Default 200 milliseconds.

       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
              kilobytes,   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.
              Default is 86400 seconds (1  day).  If  the  maximum  kicks  in,
              responses  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.
              Default 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
              contains roundtrip timing and EDNS support information.  Default
              is 900.

       infra-lame-ttl: <seconds>
              The  time  to  live  when a delegation is discovered to be lame.
              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-lame-size: <number>
              Number of bytes that the lameness cache per host is  allowed  to
              use.  Default is 10 kb, which gives maximum storage for a couple
              score zones, depending on the lame zone name lengths.

       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.

       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
              appended  for a classless network block. The action can be deny,
              refuse, allow or allow_snoop.

              The action deny stops queries from hosts from that netblock.

              The action refuse stops queries  too,  but  sends  a  DNS  rcode
              REFUSED 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
              operations   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
              policy, and dropping may result in (possibly excessive)  retried
              queries.

       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
              directory, or as an absolute path relative to the original root.
              In  the  last  case  the  path  is adjusted to remove the unused
              portion.

              The pidfile can  be  either  a  relative  path  to  the  working
              directory, or an absolute path relative to the original root. It
              is written just prior to chroot and dropping  permissions.  This
              allows  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
              entropy) from inside the chroot.

              If given a chroot is done to the given directory. The default is
              "/var/lib/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
              requires  privileges,  then  a  reload  will  fail; a restart is
              needed.

       directory: <directory>
              Sets  the  working  directory  for  the  program.   Default   is
              "/etc/unbound".

       logfile: <filename>
              If  ""  is  given,  logging  goes  to  stderr,  or  nowhere once
              daemonized.  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
              syslog(3).  The log facility LOG_DAEMON is used,  with  identity
              "unbound".  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.

       pidfile: <filename>
              The   process   id   is   written   to   the  file.  Default  is
              "/var/run/unbound.pid".  So,
              kill -HUP ‘cat /var/run/unbound.pid‘
              triggers a reload,
              kill -QUIT ‘cat /var/run/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
              default  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
              numbers.  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
              unbound 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
              legal  protocol  wise  to send these, and could be necessary for
              operation if TSIG or EDNS payload is very large.

       harden-glue: <yes or no>
              Will trust glue only if it  is  within  the  servers  authority.
              Default 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
              attack that disables security for a zone. Default is on.

       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
              validation 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.

       use-caps-for-id: <yes or no>
              Use  0x20-encoded  random  bits  in  the  query  to  foil  spoof
              attempts.  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
              addresses on your private network, and are  not  allowed  to  be
              returned  for  public  internet  names.   Any  occurence of such
              addresses 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
              additional names using private-domain.  No private addresses are
              enabled 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  192.254.0.0/16 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
              spamblocklists as they use that.

       private-domain: <domain name>
              Allow this domain, and all its  subdomains  to  contain  private
              addresses.   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
              action  is  to  clear  the  rrset  and message caches, hopefully
              flushing away any poison.  A value of 10 million  is  suggested.
              Default 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.

       module-config: <"module names">
              Module  configuration,  a  list  of  module  names  separated by
              spaces, 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
              entries can appear in the file. The format of the  file  is  the
              standard  DNS  Zone  file  format.   Default  is "", or no trust
              anchor file.

       trust-anchor: <"Resource Record">
              A DS or DNSKEY RR for a key  to  use  for  validation.  Multiple
              entries  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 ignored.  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-anchor-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
              ignored towards the domain name.  So a trust  anchor  above  the
              domain  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 domains that are treated as if unsigned.   If  you  set
              trust anchors for the domain they override this setting (and the
              domain is secured).

              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
              verifying  RRSIG  inception and expiration dates, instead of the
              current date. Do not set this unless you are debugging signature
              inception and expiration.

       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  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 signatures.

       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  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
              instead. 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
              section  of  secure  messages  that  are  not  signed  properly.
              Messages  that  are  insecure, bogus, indeterminate or unchecked
              are not affected. 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.
              Regardless  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.

       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".

       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.

       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
              kilobytes,  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).

       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,  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 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
                 resolved normally.  If the query  is  for  a  name  given  in
                 localdata  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 default.

            redirect
                 The query is answered from the local data for the zone  name.
                 There  may  be  no  local  data  beneath the zone name.  This
                 answers 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   a   different   address,   with   local-zone:
                 "example.com."   redirect  and  local-data:  "example.com.  A
                 127.0.0.1"     queries      for      www.example.com      and
                 www.foo.example.com are redirected.

            nodefault
                 Used  to turn off default contents for AS112 zones. The other
                 types also turn  off  default  contents  for  the  zone.  The
                 ’nodefault’  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
       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
       ’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
                 local-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, 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
                 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
            determines further processing. If local-data is configured that is
            not a subdomain of  a  local-zone,  a  transparent  local-zone  is
            configured.   For  record types such as TXT, use single quotes, as
            in local-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
            below.

       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
       control  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
       unbound-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 953
            (that is the same port number named uses to listen to  rndc).   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
            unbound_server.pem.    This   file    is    generated    by    the
            unbound-control-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_control.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_control.pem.  This certificate has to be signed  with  the
            server    certificate.     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
       nameservers is used. Class IN is assumed.

       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
       authoritative 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
       authoritative 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.

   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 have to
       handle further  recursion  for  the  query.  Class  IN  is  assumed.  A
       forward-zone entry with name "." and a forward-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.

   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-conf:
       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
       service  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 service, 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: 16  # 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
            infra-cache-lame-size: 1k
            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

       /etc/unbound
              default unbound working directory.

       /var/lib/unbound
              default chroot(2) location.

       /etc/unbound/unbound.conf
              unbound configuration file.

       /var/run/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
       distribution for further details.