.TH "unbound.conf" "5" "Aug 7, 2008" "NLnet Labs" "unbound 1.0.2"
.\"
.\" unbound.conf.5 -- unbound.conf manual
.\"
.\" Copyright (c) 2007, NLnet Labs. All rights reserved.
.\"
.\" See LICENSE for the license.
.\"
.\"
.SH "NAME"
.LP
.B unbound.conf
\- Unbound configuration file.
.SH "SYNOPSIS"
.LP
.B unbound.conf
.SH "DESCRIPTION"
.LP
.B unbound.conf
is used to configure
\fIunbound\fR(8).
The file format has attributes and values. Some attributes have attributes inside them.
The notation is: attribute: value.
.P
Comments start with # and last to the end of line. Empty lines are
ignored as is whitespace at the beginning of a line.
.P
The utility
\fIunbound\-checkconf\fR(8)
can be used to check unbound.conf prior to usage.
.SH "EXAMPLE"
An example config file is shown below. Copy this to /etc/unbound/unbound.conf
and start the server with:
.P
.nf
$ unbound \-c /etc/unbound/unbound.conf
.fi
.P
Most settings are the defaults. Stop the server with:
.P
.nf
$ kill `cat /etc/unbound/unbound.pid`
.fi
.P
Below is a minimal config file. The source distribution contains an extensive
example.conf file with all the options.
.P
.nf
# unbound.conf(5) config file for unbound(8).
server:
directory: "/etc/unbound"
username: unbound # make sure it can write to pidfile.
# 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
.fi
.SH "FILE FORMAT"
.LP
There must be whitespace between keywords. Attribute keywords end with a colon ':'. An attribute
is followed by its containing attributes, or a value.
.P
Files can be included using the
.B 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.
.SS "Server Options"
These options are part of the
.B server:
clause.
.TP
.B verbosity: \fI<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.
Default is level 1. The verbosity can also be increased from the commandline,
see
\fIunbound\fR(8).
.TP
.B statistics-interval: \fI<seconds>
The number of seconds between printing statistics to the log for every thread.
Disable with value 0 or "". Default is disabled.
.TP
.B statistics-cumulative: \fI<yes or no>
If enabled, statistics are cumulative since starting unbound, without clearing
the statistics counters after logging the statistics. Default is no.
.TP
.B num\-threads: \fI<number>
The number of threads to create to serve clients. Use 1 for no threading.
.TP
.B port: \fI<port number>
The port number, default 53, on which the server responds to queries.
.TP
.B interface: \fI<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.
.TP
.B interface-automatic: \fI<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.
.TP
.B outgoing\-interface: \fI<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
.B interface:
and
.B outgoing\-interface:
lines, the interfaces are then used for both purposes. Outgoing queries are
sent via a random outgoing interface to counter spoofing.
.TP
.B outgoing\-range: \fI<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.
.TP
.B outgoing\-port\-permit: \fI<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.
.TP
.B outgoing\-port\-avoid: \fI<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.
.TP
.B outgoing\-num\-tcp: \fI<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.
.TP
.B incoming\-num\-tcp: \fI<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.
.TP
.B msg\-buffer\-size: \fI<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.
.TP
.B msg\-cache\-size: \fI<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).
.TP
.B msg\-cache\-slabs: \fI<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.
.TP
.B num\-queries\-per\-thread: \fI<number>
The number of queries that every thread will service simultaneously.
If more queries arrive that need servicing, they are dropped. This forces
the client to resend after a timeout; allowing the server time to work on
the existing queries. Default 1024.
.TP
.B rrset\-cache\-size: \fI<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).
.TP
.B rrset\-cache\-slabs: \fI<number>
Number of slabs in the RRset cache. Slabs reduce lock contention by threads.
Must be set to a power of 2.
.TP
.B cache\-max\-ttl: \fI<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.
.TP
.B infra\-host\-ttl: \fI<seconds>
Time to live for entries in the host cache. The host cache contains
roundtrip timing and EDNS support information. Default is 900.
.TP
.B infra\-lame\-ttl: \fI<seconds>
The time to live when a delegation is discovered to be lame. Default is 900.
.TP
.B infra\-cache\-slabs: \fI<number>
Number of slabs in the infrastructure cache. Slabs reduce lock contention
by threads. Must be set to a power of 2.
.TP
.B infra\-cache\-numhosts: \fI<number>
Number of hosts for which information is cached. Default is 10000.
.TP
.B infra\-cache\-lame\-size: \fI<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.
.TP
.B do\-ip4: \fI<yes or no>
Enable or disable whether ip4 queries are answered or issued. Default is yes.
.TP
.B do\-ip6: \fI<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.
.TP
.B do\-udp: \fI<yes or no>
Enable or disable whether UDP queries are answered or issued. Default is yes.
.TP
.B do\-tcp: \fI<yes or no>
Enable or disable whether TCP queries are answered or issued. Default is yes.
.TP
.B do\-daemonize: \fI<yes or no>
Enable or disable whether the unbound server forks into the background as
a daemon. Default is yes.
.TP
.B access\-control: \fI<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 or allow.
Deny stops queries from hosts from that netblock.
Refuse stops queries too, but sends a DNS rcode REFUSED error message back.
Allow gives access to clients from that netblock.
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.
.TP
.B chroot: \fI<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.
.IP
All other file paths (working dir, pidfile, logfile, roothints,
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.
.IP
Additionally, unbound may need to access /dev/random (for entropy)
and to /dev/log (if you use syslog) from inside the chroot.
.IP
If given a chroot is done to the given directory. The default is
"@UNBOUND_CHROOT_DIR@". If you give "" no chroot is performed.
.TP
.B username: \fI<name>
If given, after binding the port the user privileges are dropped. Default is
"@UNBOUND_USERNAME@". If you give username: "" no user change is performed.
.IP
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.
.TP
.B directory: \fI<directory>
Sets the working directory for the program. Default is "@UNBOUND_RUN_DIR@".
.TP
.B logfile: \fI<filename>
If "" is given, logging goes to stderr, or nowhere once daemonized.
The logfile is appended to, in the following format:
.nf
[seconds since 1970] unbound[pid:tid]: type: message.
.fi
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.
.TP
.B use\-syslog: \fI<yes or no>
Sets unbound to send log messages to the syslogd, using
\fIsyslog\fR(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.
.TP
.B pidfile: \fI<filename>
The process id is written to the file. Default is "@UNBOUND_PIDFILE@".
So,
.nf
kill \-HUP `cat @UNBOUND_PIDFILE@`
.fi
triggers a reload,
.nf
kill \-QUIT `cat @UNBOUND_PIDFILE@`
.fi
gracefully terminates.
.TP
.B root\-hints: \fI<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.
.TP
.B hide\-identity: \fI<yes or no>
If enabled id.server and hostname.bind queries are refused.
.TP
.B identity: \fI<string>
Set the identity to report. If set to "", the default, then the hostname
of the server is returned.
.TP
.B hide\-version: \fI<yes or no>
If enabled version.server and version.bind queries are refused.
.TP
.B version: \fI<string>
Set the version to report. If set to "", the default, then the package
version is returned.
.TP
.B target\-fetch\-policy: \fI<"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.
.IP
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.
.IP
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.
.TP
.B harden\-short\-bufsize: \fI<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.
.TP
.B harden\-large\-queries: \fI<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.
.TP
.B harden\-glue: \fI<yes or no>
Will trust glue only if it is within the servers authority. Default is on.
.TP
.B harden\-dnssec\-stripped: \fI<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.
.TP
.B use\-caps\-for\-id: \fI<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, because some caching forwarders may not
support this. It is known that some authority servers do not support 0x20,
and resolution will fail for them. A solution is on the TODO list.
This feature is an experimental implementation of draft dns\-0x20.
.TP
.B do\-not\-query\-address: \fI<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.
.TP
.B do\-not\-query\-localhost: \fI<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.
.TP
.B module\-config: \fI<"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.
You must also set trust\-anchors for validation to be useful.
.TP
.B trust\-anchor\-file: \fI<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.
.TP
.B trust\-anchor: \fI<"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.
.TP
.B trusted\-keys\-file: \fI<filename>
File with trusted keys for validation. Specify more than one file
with several entries, one file per entry. Like \fBtrust\-anchor\-file\fR
but has a different file format. Format is BIND\-9 style format,
the trusted\-keys { name flag proto algo "key"; }; clauses are read.
.TP
.B val\-override\-date: \fI<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.
.TP
.B val\-bogus\-ttl: \fI<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 900.
The time interval prevents repeated revalidation of bogus data.
.TP
.B val\-clean\-additional: \fI<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.
.TP
.B val\-permissive\-mode: \fI<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".
.TP
.B val\-nsec3\-keysize\-iterations: \fI<"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.
.TP
.B key\-cache\-size: \fI<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).
.TP
.B key\-cache\-slabs: \fI<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.
.TP
.B local\-zone: \fI<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.
.IP
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.
.TP 10
\h'5'\fIdeny\fR
Do not send an answer, drop the query.
If there is a match from local data, the query is answered.
.TP 10
\h'5'\fIrefuse\fR
Send an error message reply, with rcode REFUSED.
If there is a match from local data, the query is answered.
.TP 10
\h'5'\fIstatic\fR
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.
.TP 10
\h'5'\fItransparent\fR
If there is a match from local data, the query is answered.
Otherwise, the query is resolved normally.
If no local\-zone is given local\-data causes a transparent zone
to be created by default.
.TP 10
\h'5'\fIredirect\fR
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.
.TP 10
\h'5'\fInodefault\fR
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.
.P
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.
.TP 10
\h'5'\fIlocalhost\fR
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:
.nf
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"
.fi
.TP 10
\h'5'\fIreverse IPv4 loopback\fR
Default content:
.nf
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."
.fi
.TP 10
\h'5'\fIreverse IPv6 loopback\fR
Default content:
.nf
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."
.fi
.TP 10
\h'5'\fIreverse RFC1918 local use zones\fR
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 \fBlocal\-zone:\fR is set static and as \fBlocal\-data:\fR SOA and NS
records are provided.
.TP 10
\h'5'\fIreverse RFC3330 IP4 this, link\-local, testnet and broadcast\fR
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.
.TP 10
\h'5'\fIreverse RFC4291 IP6 unspecified\fR
Reverse data for zone
.nf
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.
.fi
.TP 10
\h'5'\fIreverse RFC4193 IPv6 Locally Assigned Local Addresses\fR
Reverse data for zone D.F.ip6.arpa.
.TP 10
\h'5'\fIreverse RFC4291 IPv6 Link Local Addresses\fR
Reverse data for zones 8.E.F.ip6.arpa to B.E.F.ip6.arpa.
.TP 10
\h'5'\fIreverse IPv6 Example Prefix\fR
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:
.nf
local-zone: 8.B.D.0.1.0.0.2.ip6.arpa. nodefault
.fi
This also works with the other default zones.
.\" End of local-zone listing.
.TP 5
.B local\-data: \fI"<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"'.
.IP
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.
.SS "Stub Zone Options"
.LP
There may be multiple
.B 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.
.P
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
.B stub\-addr:
<ip address of host[@port]>.
The unbound resolver can then access the data, without referring to the
public internet for it.
.P
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.
.TP
.B name: \fI<domain name>
Name of the stub zone.
.TP
.B stub\-host: \fI<domain name>
Name of stub zone nameserver. Is itself resolved before it is used.
.TP
.B stub\-addr: \fI<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.
.SS "Forward Zone Options"
.LP
There may be multiple
.B 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).
.TP
.B name: \fI<domain name>
Name of the forward zone.
.TP
.B forward\-host: \fI<domain name>
Name of server to forward to. Is itself resolved before it is used.
.TP
.B forward\-addr: \fI<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.
.SH "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.
.P
.nf
# 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
num\-queries\-per\-thread: 30
target\-fetch\-policy: "2 1 0 0 0 0"
harden\-large\-queries: "yes"
harden\-short\-bufsize: "yes"
.fi
.SH "FILES"
.TP
.I @UNBOUND_RUN_DIR@
default unbound working directory.
.TP
.I @UNBOUND_CHROOT_DIR@
default
\fIchroot\fR(2)
location.
.TP
.I @ub_conf_file@
unbound configuration file.
.TP
.I @UNBOUND_PIDFILE@
default unbound pidfile with process ID of the running daemon.
.TP
.I unbound.log
unbound log file. default is to log to
\fIsyslog\fR(3).
.SH "SEE ALSO"
\fIunbound\fR(8),
\fIunbound\-checkconf\fR(8).
.SH "AUTHORS"
.B Unbound
was written by NLnet Labs. Please see CREDITS file
in the distribution for further details.