unbound.conf(5) unbound 1.18.0 unbound.conf(5) #
unbound.conf(5) unbound 1.18.0 unbound.conf(5)
NNAAMMEE #
uunnbboouunndd..ccoonnff - Unbound configuration file.
SSYYNNOOPPSSIISS #
uunnbboouunndd..ccoonnff
DDEESSCCRRIIPPTTIIOONN #
uunnbboouunndd..ccoonnff is used to configure _u_n_b_o_u_n_d(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 _u_n_b_o_u_n_d_-_c_h_e_c_k_c_o_n_f(8) can be used to check unbound.conf prior
to usage.
FFIILLEE FFOORRMMAATT #
There must be whitespace between keywords. Attribute keywords end with a
colon ':'. An attribute is followed by a value, or its containing
attributes in which case it is referred to as a clause. Clauses can be
repeated throughout the file (or included files) to group attributes
under the same clause.
Files can be included using the iinncclluuddee:: directive. It can appear
anywhere, 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 included files works, relative pathnames for the included names
work if the directory where the daemon is started equals its
chroot/working directory or is specified before the include statement
with directory: dir. Wildcards can be used to include multiple files,
see _g_l_o_b(7).
For a more structural include option, the iinncclluuddee--ttoopplleevveell:: directive can
be used. This closes whatever clause is currently active (if any) and
forces the use of clauses in the included files and right after this
directive.
SSeerrvveerr OOppttiioonnss These options are part of the sseerrvveerr:: clause.
vveerrbboossiittyy:: _<_n_u_m_b_e_r_>
The verbosity number, level 0 means no verbosity, only errors.
Level 1 gives operational information. Level 2 gives detailed
operational information including short information per query.
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
_u_n_b_o_u_n_d(8).
ssttaattiissttiiccss--iinntteerrvvaall:: _<_s_e_c_o_n_d_s_>
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.
ssttaattiissttiiccss--ccuummuullaattiivvee:: _<_y_e_s _o_r _n_o_>
If enabled, statistics are cumulative since starting Unbound,
without clearing the statistics counters after logging the
statistics. Default is no.
eexxtteennddeedd--ssttaattiissttiiccss:: _<_y_e_s _o_r _n_o_>
If enabled, extended statistics are printed from
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l(8). Default is off, because keeping track of more
statistics takes time. The counters are listed in
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l(8).
ssttaattiissttiiccss--iinnhhiibbiitt--zzeerroo:: _<_y_e_s _o_r _n_o_>
If enabled, selected extended statistics with a value of 0 are
inhibited from printing with _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l(8). These are query
types, query classes, query opcodes, answer rcodes (except
NOERROR, FORMERR, SERVFAIL, NXDOMAIN, NOTIMPL, REFUSED) and RPZ
actions. Default is on.
nnuumm--tthhrreeaaddss:: _<_n_u_m_b_e_r_>
The number of threads to create to serve clients. Use 1 for no
threading.
ppoorrtt:: _<_p_o_r_t _n_u_m_b_e_r_>
The port number, default 53, on which the server responds to
queries.
iinntteerrffaaccee:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_>
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. If an interface name is used instead of an ip address,
the list of ip addresses on that interface are used. 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 specified the
default port (from ppoorrtt) is used.
iipp--aaddddrreessss:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_>
Same as interface: (for ease of compatibility with nsd.conf).
iinntteerrffaaccee--aauuttoommaattiicc:: _<_y_e_s _o_r _n_o_>
Listen on all addresses on all (current and future) interfaces,
detect the source interface on UDP queries and copy them to
replies. This is a lot like ip-transparent, but this option
services all interfaces whilst with ip-transparent you can select
which (future) interfaces Unbound provides service on. This
feature is experimental, and needs support in your OS for
particular socket options. Default value is no.
iinntteerrffaaccee--aauuttoommaattiicc--ppoorrttss:: _<_s_t_r_i_n_g_>
List the port numbers that interface-automatic listens on. If
empty, the default port is listened on. The port numbers are
separated by spaces in the string. Default is "".
This can be used to have interface automatic to deal with the
interface, and listen on the normal port number, by including it
in the list, and also https or dns over tls port numbers by
putting them in the list as well.
oouuttggooiinngg--iinntteerrffaaccee:: _<_i_p _a_d_d_r_e_s_s _o_r _i_p_6 _n_e_t_b_l_o_c_k_>
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 iinntteerrffaaccee:: and oouuttggooiinngg--iinntteerrffaaccee::
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 address
taken from the netblock to counter spoofing. Requires the IPv6
netblock to be routed to the host running Unbound, and requires OS
support for unprivileged non-local binds (currently only supported
on Linux). Several netblocks may be specified with multiple
oouuttggooiinngg--iinntteerrffaaccee:: options, but do not specify both an individual
IPv6 address and an IPv6 netblock, or the randomisation will be
compromised. Consider combining with pprreeffeerr--iipp66:: yyeess to increase
the likelihood of IPv6 nameservers being 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
oouuttggooiinngg--rraannggee:: _<_n_u_m_b_e_r_>
Number of ports to open. This number of file descriptors can be
opened per thread. Must be at least 1. Default depends on compile
options. Larger numbers need extra resources from the operating
system. For performance a very large value is best, use libevent
to make this possible.
oouuttggooiinngg--ppoorrtt--ppeerrmmiitt:: _<_p_o_r_t _n_u_m_b_e_r _o_r _r_a_n_g_e_>
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 oouuttggooiinngg--ppoorrtt--ppeerrmmiitt and oouuttggooiinngg--ppoorrtt--aavvooiidd 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.
oouuttggooiinngg--ppoorrtt--aavvooiidd:: _<_p_o_r_t _n_u_m_b_e_r _o_r _r_a_n_g_e_>
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.
oouuttggooiinngg--nnuumm--ttccpp:: _<_n_u_m_b_e_r_>
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. For larger installations
increasing this value is a good idea.
iinnccoommiinngg--nnuumm--ttccpp:: _<_n_u_m_b_e_r_>
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.
eeddnnss--bbuuffffeerr--ssiizzee:: _<_n_u_m_b_e_r_>
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.
Default is 1232 which is the DNS Flag Day 2020 recommendation.
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).
mmaaxx--uuddpp--ssiizzee:: _<_n_u_m_b_e_r_>
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
1232. The default value is the same as the default for
edns-buffer-size.
ssttrreeaamm--wwaaiitt--ssiizzee:: _<_n_u_m_b_e_r_>
Number of bytes size maximum to use for waiting stream buffers.
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). As TCP and TLS streams queue up multiple results,
the amount of memory used for these buffers does not exceed this
number, otherwise the responses are dropped. This manages the
total memory usage of the server (under heavy use), the number of
requests that can be queued up per connection is also limited,
with further requests waiting in TCP buffers.
mmssgg--bbuuffffeerr--ssiizzee:: _<_n_u_m_b_e_r_>
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.
mmssgg--ccaacchhee--ssiizzee:: _<_n_u_m_b_e_r_>
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).
mmssgg--ccaacchhee--ssllaabbss:: _<_n_u_m_b_e_r_>
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.
nnuumm--qquueerriieess--ppeerr--tthhrreeaadd:: _<_n_u_m_b_e_r_>
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 _j_o_s_t_l_e_-_t_i_m_e_o_u_t), 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.
jjoossttllee--ttiimmeeoouutt:: _<_m_s_e_c_>
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. The effect is that the
qps for long-lasting queries is about (numqueriesperthread / 2) /
(average time for such long queries) qps. The qps for short
queries can be about (numqueriesperthread / 2) / (jostletimeout in
whole seconds) qps per thread, about (1024/2)*5 = 2560 qps by
default.
ddeellaayy--cclloossee:: _<_m_s_e_c_>
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 packets, and
unwanted packets are added to the unwanted packet counter.
uuddpp--ccoonnnneecctt:: _<_y_e_s _o_r _n_o_>
Perform connect for UDP sockets that mitigates ICMP side channel
leakage. Default is yes.
uunnkknnoowwnn--sseerrvveerr--ttiimmee--lliimmiitt:: _<_m_s_e_c_>
The wait time in msec for waiting for an unknown server to reply.
Increase this if you are behind a slow satellite link, to eg.
1128. That would then avoid re-querying every initial query
because it times out. Default is 376 msec.
ssoo--rrccvvbbuuff:: _<_n_u_m_b_e_r_>
If not 0, then set the SO_RCVBUF socket option to get more buffer
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.
ssoo--ssnnddbbuuff:: _<_n_u_m_b_e_r_>
If not 0, then set the SO_SNDBUF socket option to get more buffer
space on UDP port 53 outgoing queries. This for very busy servers
handles spikes in answer traffic, otherwise 'send: resource
temporarily unavailable' can get logged, the buffer overrun 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.
ssoo--rreeuusseeppoorrtt:: _<_y_e_s _o_r _n_o_>
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 yes. 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 available at compile
time, if that works it is used, if it fails, it continues silently
(unless verbosity 3) without the option. At extreme load it could
be better to turn it off to distribute the queries evenly,
reported for Linux systems (4.4.x).
iipp--ttrraannssppaarreenntt:: _<_y_e_s _o_r _n_o_>
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-existent
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 permissions on some
systems. The option uses IP_BINDANY on FreeBSD systems and
SO_BINDANY on OpenBSD systems.
iipp--ffrreeeebbiinndd:: _<_y_e_s _o_r _n_o_>
If yes, then use IP_FREEBIND socket option on sockets where
Unbound 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 available.
iipp--ddssccpp:: _<_n_u_m_b_e_r_>
The value of the Differentiated Services Codepoint (DSCP) in the
differentiated services field (DS) of the outgoing IP packet
headers. The field replaces the outdated IPv4 Type-Of-Service
field and the IPv6 traffic class field.
rrrrsseett--ccaacchhee--ssiizzee:: _<_n_u_m_b_e_r_>
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).
rrrrsseett--ccaacchhee--ssllaabbss:: _<_n_u_m_b_e_r_>
Number of slabs in the RRset cache. Slabs reduce lock contention
by threads. Must be set to a power of 2.
ccaacchhee--mmaaxx--ttttll:: _<_s_e_c_o_n_d_s_>
Time to live maximum for RRsets and messages in the cache. Default
is 86400 seconds (1 day). When the 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. Downstream
clients also see the lower TTL.
ccaacchhee--mmiinn--ttttll:: _<_s_e_c_o_n_d_s_>
Time to live minimum for RRsets and messages in the cache. Default
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.
ccaacchhee--mmaaxx--nneeggaattiivvee--ttttll:: _<_s_e_c_o_n_d_s_>
Time to live maximum for negative responses, these have a SOA in
the authority section that is limited in time. Default is 3600.
This applies to nxdomain and nodata answers.
iinnffrraa--hhoosstt--ttttll:: _<_s_e_c_o_n_d_s_>
Time to live for entries in the host cache. The host cache
contains roundtrip timing, lameness and EDNS support information.
Default is 900.
iinnffrraa--ccaacchhee--ssllaabbss:: _<_n_u_m_b_e_r_>
Number of slabs in the infrastructure cache. Slabs reduce lock
contention by threads. Must be set to a power of 2.
iinnffrraa--ccaacchhee--nnuummhhoossttss:: _<_n_u_m_b_e_r_>
Number of hosts for which information is cached. Default is 10000.
iinnffrraa--ccaacchhee--mmiinn--rrtttt:: _<_m_s_e_c_>
Lower limit for dynamic retransmit timeout calculation in
infrastructure cache. Default is 50 milliseconds. Increase this
value if using forwarders needing more time to do recursive name
resolution.
iinnffrraa--ccaacchhee--mmaaxx--rrtttt:: _<_m_s_e_c_>
Upper limit for dynamic retransmit timeout calculation in
infrastructure cache. Default is 2 minutes.
iinnffrraa--kkeeeepp--pprroobbiinngg:: _<_y_e_s _o_r _n_o_>
If enabled the server keeps probing hosts that are down, in the
one probe at a time regime. Default is no. Hosts that are down,
eg. they did not respond during the one probe at a time period,
are marked as down and it may take iinnffrraa--hhoosstt--ttttll time to get
probed again.
ddeeffiinnee--ttaagg:: _<_"_l_i_s_t _o_f _t_a_g_s_"_>
Define the tags that can be used with local-zone and
access-control. Enclose the list between quotes ("") and put
spaces between tags.
ddoo--iipp44:: _<_y_e_s _o_r _n_o_>
Enable or disable whether ip4 queries are answered or issued.
Default is yes.
ddoo--iipp66:: _<_y_e_s _o_r _n_o_>
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.
pprreeffeerr--iipp44:: _<_y_e_s _o_r _n_o_>
If enabled, prefer IPv4 transport for sending DNS queries to
internet nameservers. Default is no. Useful if the IPv6 netblock
the server has, the entire /64 of that is not owned by one
operator and the reputation of the netblock /64 is an issue, using
IPv4 then uses the IPv4 filters that the upstream servers have.
pprreeffeerr--iipp66:: _<_y_e_s _o_r _n_o_>
If enabled, prefer IPv6 transport for sending DNS queries to
internet nameservers. Default is no.
ddoo--uuddpp:: _<_y_e_s _o_r _n_o_>
Enable or disable whether UDP queries are answered or issued.
Default is yes.
ddoo--ttccpp:: _<_y_e_s _o_r _n_o_>
Enable or disable whether TCP queries are answered or issued.
Default is yes.
ttccpp--mmssss:: _<_n_u_m_b_e_r_>
Maximum segment size (MSS) of TCP socket on which the server
responds 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). Default
is system default MSS determined by interface MTU and negotiation
between server and client.
oouuttggooiinngg--ttccpp--mmssss:: _<_n_u_m_b_e_r_>
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
interface MTU and negotiation between Unbound and other servers.
ttccpp--iiddllee--ttiimmeeoouutt:: _<_m_s_e_c_>
The period Unbound will wait for a query on a TCP connection. If
this timeout expires Unbound closes the connection. This option
defaults to 30000 milliseconds. When the number of free incoming
TCP buffers falls below 50% of the total number configured, the
option value used is progressively reduced, first to 1% of the
configured value, then to 0.2% of the configured value if the
number of free buffers falls below 35% of the total number
configured, and finally to 0 if the number of free buffers falls
below 20% of the total number configured. A minimum timeout of 200
milliseconds is observed regardless of the option value used.
ttccpp--rreeuussee--ttiimmeeoouutt:: _<_m_s_e_c_>
The period Unbound will keep TCP persistent connections open to
authority servers. This option defaults to 60000 milliseconds.
mmaaxx--rreeuussee--ttccpp--qquueerriieess:: _<_n_u_m_b_e_r_>
The maximum number of queries that can be sent on a persistent TCP
connection. This option defaults to 200 queries.
ttccpp--aauutthh--qquueerryy--ttiimmeeoouutt:: _<_n_u_m_b_e_r_>
Timeout in milliseconds for TCP queries to auth servers. This
option defaults to 3000 milliseconds.
eeddnnss--ttccpp--kkeeeeppaalliivvee:: _<_y_e_s _o_r _n_o_>
Enable or disable EDNS TCP Keepalive. Default is no.
eeddnnss--ttccpp--kkeeeeppaalliivvee--ttiimmeeoouutt:: _<_m_s_e_c_>
The period Unbound will wait for a query on a TCP connection when
EDNS TCP Keepalive is active. If this timeout expires Unbound
closes the connection. If the client supports the EDNS TCP
Keepalive option, Unbound sends the timeout value to the client to
encourage it to close the connection before the server times out.
This option defaults to 120000 milliseconds. When the number of
free incoming TCP buffers falls below 50% of the total number
configured, the advertised timeout is progressively reduced to 1%
of the configured value, then to 0.2% of the configured value if
the number of free buffers falls below 35% of the total number
configured, and finally to 0 if the number of free buffers falls
below 20% of the total number configured. A minimum actual
timeout of 200 milliseconds is observed regardless of the
advertised timeout.
ssoocckk--qquueeuuee--ttiimmeeoouutt:: _<_s_e_c_>
UDP queries that have waited in the socket buffer for a long time
can be dropped. Default is 0, disabled. The time is set in
seconds, 3 could be a good value to ignore old queries that likely
the client does not need a reply for any more. This could happen
if the host has not been able to service the queries for a while,
i.e. Unbound is not running, and then is enabled again. It uses
timestamp socket options.
ttccpp--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Enable or disable whether the upstream queries use TCP only for
transport. Default is no. Useful in tunneling scenarios. If set
to no you can specify TCP transport only for selected forward or
stub zones using forward-tcp-upstream or stub-tcp-upstream
respectively.
uuddpp--uuppssttrreeaamm--wwiitthhoouutt--ddoowwnnssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Enable udp upstream even if do-udp is no. Default is no, and this
does not change anything. Useful for TLS service providers, that
want no udp downstream but use udp to fetch data upstream.
ttllss--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Enabled or disable whether the upstream queries use TLS only for
transport. Default is no. Useful in tunneling scenarios. The
TLS contains plain DNS in TCP wireformat. The other server must
support this (see ttllss--sseerrvviiccee--kkeeyy). If you enable this, also
configure a tls-cert-bundle or use tls-win-cert or tls-system-cert
to load CA certs, otherwise the connections cannot be
authenticated. This option enables TLS for all of them, but if you
do not set this you can configure TLS specifically for some
forward zones with forward-tls-upstream. And also with
stub-tls-upstream.
ssssll--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Alternate syntax for ttllss--uuppssttrreeaamm. If both are present in the
config file the last is used.
ttllss--sseerrvviiccee--kkeeyy:: _<_f_i_l_e_>
If enabled, the server provides DNS-over-TLS or DNS-over-HTTPS
service on the TCP ports marked implicitly or explicitly for these
services with tls-port or https-port. The file must contain the
private key for the TLS session, the public certificate is in the
tls-service-pem file and it must also be specified if
tls-service-key is specified. The default is "", turned off.
Enabling or disabling this service requires a restart (a reload is
not enough), because the key is read while root permissions are
held and before chroot (if any). The ports enabled implicitly or
explicitly via ttllss--ppoorrtt:: and hhttttppss--ppoorrtt:: do not provide normal DNS
TCP service. Unbound needs to be compiled with libnghttp2 in order
to provide DNS-over-HTTPS.
ssssll--sseerrvviiccee--kkeeyy:: _<_f_i_l_e_>
Alternate syntax for ttllss--sseerrvviiccee--kkeeyy.
ttllss--sseerrvviiccee--ppeemm:: _<_f_i_l_e_>
The public key certificate pem file for the tls service. Default
is "", turned off.
ssssll--sseerrvviiccee--ppeemm:: _<_f_i_l_e_>
Alternate syntax for ttllss--sseerrvviiccee--ppeemm.
ttllss--ppoorrtt:: _<_n_u_m_b_e_r_>
The port number on which to provide TCP TLS service, default 853,
only interfaces configured with that port number as @number get
the TLS service.
ssssll--ppoorrtt:: _<_n_u_m_b_e_r_>
Alternate syntax for ttllss--ppoorrtt.
ttllss--cceerrtt--bbuunnddllee:: _<_f_i_l_e_>
If null or "", no file is used. Set it to the certificate bundle
file, for example "/etc/pki/tls/certs/ca-bundle.crt". These
certificates are used for authenticating connections made to
outside peers. For example auth-zone urls, and also DNS over TLS
connections. It is read at start up before permission drop and
chroot.
ssssll--cceerrtt--bbuunnddllee:: _<_f_i_l_e_>
Alternate syntax for ttllss--cceerrtt--bbuunnddllee.
ttllss--wwiinn--cceerrtt:: _<_y_e_s _o_r _n_o_>
Add the system certificates to the cert bundle certificates for
authentication. If no cert bundle, it uses only these
certificates. Default is no. On windows this option uses the
certificates from the cert store. Use the tls-cert-bundle option
on other systems. On other systems, this option enables the system
certificates.
ttllss--ssyysstteemm--cceerrtt:: _<_y_e_s _o_r _n_o_>
This the same setting as the tls-win-cert setting, under a
different name. Because it is not windows specific.
ttllss--aaddddiittiioonnaall--ppoorrtt:: _<_p_o_r_t_n_r_>
List portnumbers as tls-additional-port, and when interfaces are
defined, eg. with the @port suffix, as this port number, they
provide dns over TLS service. Can list multiple, each on a new
statement.
ttllss--sseessssiioonn--ttiicckkeett--kkeeyyss:: _<_f_i_l_e_>
If not "", lists files with 80 bytes of random contents that are
used to perform TLS session resumption for clients using the
Unbound server. These files contain the secret key for the TLS
session tickets. First key use to encrypt and decrypt TLS session
tickets. Other keys use to decrypt only. With this you can roll
over to new keys, by generating a new first file and allowing
decrypt of the old file by listing it after the first file for
some time, after the wait clients are not using the old key any
more and the old key can be removed. One way to create the file
is dd if=/dev/random bs=1 count=80 of=ticket.dat The first 16
bytes should be different from the old one if you create a second
key, that is the name used to identify the key. Then there is 32
bytes random data for an AES key and then 32 bytes random data for
the HMAC key.
ttllss--cciipphheerrss:: _<_s_t_r_i_n_g _w_i_t_h _c_i_p_h_e_r _l_i_s_t_>
Set the list of ciphers to allow when serving TLS. Use "" for
defaults, and that is the default.
ttllss--cciipphheerrssuuiitteess:: _<_s_t_r_i_n_g _w_i_t_h _c_i_p_h_e_r_s_u_i_t_e_s _l_i_s_t_>
Set the list of ciphersuites to allow when serving TLS. This is
for newer TLS 1.3 connections. Use "" for defaults, and that is
the default.
ppaadd--rreessppoonnsseess:: _<_y_e_s _o_r _n_o_>
If enabled, TLS serviced queries that contained an EDNS Padding
option will cause responses padded to the closest multiple of the
size specified in ppaadd--rreessppoonnsseess--bblloocckk--ssiizzee. Default is yes.
ppaadd--rreessppoonnsseess--bblloocckk--ssiizzee:: _<_n_u_m_b_e_r_>
The block size with which to pad responses serviced over TLS. Only
responses to padded queries will be padded. Default is 468.
ppaadd--qquueerriieess:: _<_y_e_s _o_r _n_o_>
If enabled, all queries sent over TLS upstreams will be padded to
the closest multiple of the size specified in
ppaadd--qquueerriieess--bblloocckk--ssiizzee. Default is yes.
ppaadd--qquueerriieess--bblloocckk--ssiizzee:: _<_n_u_m_b_e_r_>
The block size with which to pad queries sent over TLS upstreams.
Default is 128.
ttllss--uussee--ssnnii:: _<_y_e_s _o_r _n_o_>
Enable or disable sending the SNI extension on TLS connections.
Default is yes. Changing the value requires a reload.
hhttttppss--ppoorrtt:: _<_n_u_m_b_e_r_>
The port number on which to provide DNS-over-HTTPS service,
default 443, only interfaces configured with that port number as
@number get the HTTPS service.
hhttttpp--eennddppooiinntt:: _<_e_n_d_p_o_i_n_t _s_t_r_i_n_g_>
The HTTP endpoint to provide DNS-over-HTTPS service on. Default
"/dns-query".
hhttttpp--mmaaxx--ssttrreeaammss:: _<_n_u_m_b_e_r _o_f _s_t_r_e_a_m_s_>
Number used in the SETTINGS_MAX_CONCURRENT_STREAMS parameter in
the HTTP/2 SETTINGS frame for DNS-over-HTTPS connections. Default
100.
hhttttpp--qquueerryy--bbuuffffeerr--ssiizzee:: _<_s_i_z_e _i_n _b_y_t_e_s_>
Maximum number of bytes used for all HTTP/2 query buffers
combined. These buffers contain (partial) DNS queries waiting for
request stream completion. An RST_STREAM frame will be send to
streams exceeding this limit. 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).
hhttttpp--rreessppoonnssee--bbuuffffeerr--ssiizzee:: _<_s_i_z_e _i_n _b_y_t_e_s_>
Maximum number of bytes used for all HTTP/2 response buffers
combined. These buffers contain DNS responses waiting to be
written back to the clients. An RST_STREAM frame will be send to
streams exceeding this limit. 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).
hhttttpp--nnooddeellaayy:: _<_y_e_s _o_r _n_o_>
Set TCP_NODELAY socket option on sockets used to provide DNS-over-
HTTPS service. Ignored if the option is not available. Default is
yes.
hhttttpp--nnoottllss--ddoowwnnssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Disable use of TLS for the downstream DNS-over-HTTP connections.
Useful for local back end servers. Default is no.
pprrooxxyy--pprroottooccooll--ppoorrtt:: _<_p_o_r_t_n_r_>
List port numbers as proxy-protocol-port, and when interfaces are
defined, eg. with the @port suffix, as this port number, they
support and expect PROXYv2. In this case the proxy address will
only be used for the network communication and initial ACL (check
if the proxy itself is denied/refused by configuration). The
proxied address (if any) will then be used as the true client
address and will be used where applicable for logging, ACL,
DNSTAP, RPZ and IP ratelimiting. PROXYv2 is supported for UDP and
TCP/TLS listening interfaces. There is no support for PROXYv2 on
a DoH or DNSCrypt listening interface. Can list multiple, each on
a new statement.
uussee--ssyysstteemmdd:: _<_y_e_s _o_r _n_o_>
Enable or disable systemd socket activation. Default is no.
ddoo--ddaaeemmoonniizzee:: _<_y_e_s _o_r _n_o_>
Enable or disable whether the Unbound server forks into the
background as a daemon. Set the value to _n_o when Unbound runs as
systemd service. Default is yes.
ttccpp--ccoonnnneeccttiioonn--lliimmiitt:: _<_I_P _n_e_t_b_l_o_c_k_> _<_l_i_m_i_t_>
Allow up to _l_i_m_i_t simultaneous TCP connections from the given
netblock. When at the limit, further connections are accepted but
closed immediately. This option is experimental at this time.
aacccceessss--ccoonnttrrooll:: _<_I_P _n_e_t_b_l_o_c_k_> _<_a_c_t_i_o_n_>
The netblock is given as an IP4 or IP6 address with /size appended
for a classless network block. The action can be _d_e_n_y, _r_e_f_u_s_e,
_a_l_l_o_w, _a_l_l_o_w___s_e_t_r_d, _a_l_l_o_w___s_n_o_o_p, _a_l_l_o_w___c_o_o_k_i_e, _d_e_n_y___n_o_n___l_o_c_a_l or
_r_e_f_u_s_e___n_o_n___l_o_c_a_l. The most specific netblock match is used, if
none match _r_e_f_u_s_e is used. The order of the access-control
statements therefore does not matter.
The _d_e_n_y action stops queries from hosts from that netblock.
The _r_e_f_u_s_e action stops queries too, but sends a DNS rcode REFUSED
error message back.
The _a_l_l_o_w action 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 _a_l_l_o_w 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 _a_l_l_o_w___s_e_t_r_d action ignores the recursion desired (RD) bit and
treats all requests as if the recursion desired bit is set. Note
that this behavior violates RFC 1034 which states that a name
server should never perform recursive service unless asked via the
RD bit since this interferes with trouble shooting of name servers
and their databases. This prohibited behavior may be useful if
another DNS server must forward requests for specific zones to a
resolver DNS server, but only supports stub domains and sends
queries to the resolver DNS server with the RD bit cleared.
The _a_l_l_o_w___s_n_o_o_p action gives nonrecursive access too. This give
both recursive and non recursive access. The name _a_l_l_o_w___s_n_o_o_p
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
_a_l_l_o_w___s_n_o_o_p for your administration host.
The _a_l_l_o_w___c_o_o_k_i_e action allows access to UDP queries that contain
a valid DNS Cookie as specified in RFC 7873 and RFC 9018, when the
aannsswweerr--ccooookkiiee option is enabled. UDP queries containing only a
DNS Client Cookie and no Server Cookie, or an invalid DNS Cookie,
will receive a BADCOOKIE response including a newly generated DNS
Cookie, allowing clients to retry with that DNS Cookie. The
_a_l_l_o_w___c_o_o_k_i_e action will also accept requests over stateful
transports, regardless of the presence of an DNS Cookie and
regardless of the aannsswweerr--ccooookkiiee setting. If iipp--rraatteelliimmiitt is used,
clients with a valid DNS Cookie will bypass the ratelimit. If a
ratelimit for such clients is still needed, iipp--rraatteelliimmiitt--ccooookkiiee
can be used instead.
By default only localhost is _a_l_l_o_wed, the rest is _r_e_f_u_s_ed. The
default is _r_e_f_u_s_ed, 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.
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.
aacccceessss--ccoonnttrrooll--ttaagg:: _<_I_P _n_e_t_b_l_o_c_k_> _<_"_l_i_s_t _o_f _t_a_g_s_"_>
Assign tags to access-control elements. Clients using this access
control element use localzones that are tagged with one of these
tags. Tags must be defined in _d_e_f_i_n_e_-_t_a_g_s. Enclose list of tags
in quotes ("") and put spaces between tags. If access-control-tag
is configured for a netblock that does not have an access-control,
an access-control element with action _a_l_l_o_w is configured for this
netblock.
aacccceessss--ccoonnttrrooll--ttaagg--aaccttiioonn:: _<_I_P _n_e_t_b_l_o_c_k_> _<_t_a_g_> _<_a_c_t_i_o_n_>
Set action for particular tag for given access control element. If
you have multiple tag values, the tag used to lookup the action is
the first tag match between access-control-tag and local-zone-tag
where "first" comes from the order of the define-tag values.
aacccceessss--ccoonnttrrooll--ttaagg--ddaattaa:: _<_I_P _n_e_t_b_l_o_c_k_> _<_t_a_g_> _<_"_r_e_s_o_u_r_c_e _r_e_c_o_r_d _s_t_r_i_n_g_"_>
Set redirect data for particular tag for given access control
element.
aacccceessss--ccoonnttrrooll--vviieeww:: _<_I_P _n_e_t_b_l_o_c_k_> _<_v_i_e_w _n_a_m_e_>
Set view for given access control element.
iinntteerrffaaccee--aaccttiioonn:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_> _<_a_c_t_i_o_n_>
Similar to aacccceessss--ccoonnttrrooll:: but for interfaces.
The action is the same as the ones defined under aacccceessss--ccoonnttrrooll::.
Interfaces are _r_e_f_u_s_ed by default. By default only localhost (the
IP netblock, not the loopback interface) is _a_l_l_o_wed through the
default aacccceessss--ccoonnttrrooll:: behavior.
Note that the interface needs to be already specified with
iinntteerrffaaccee:: and that any aacccceessss--ccoonnttrrooll**:: setting overrides all
iinntteerrffaaccee--**:: settings for targeted clients.
iinntteerrffaaccee--ttaagg:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_> _<_"_l_i_s_t _o_f _t_a_g_s_"_>
Similar to aacccceessss--ccoonnttrrooll--ttaagg:: but for interfaces.
Note that the interface needs to be already specified with
iinntteerrffaaccee:: and that any aacccceessss--ccoonnttrrooll**:: setting overrides all
iinntteerrffaaccee--**:: settings for targeted clients.
iinntteerrffaaccee--ttaagg--aaccttiioonn:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_> _<_t_a_g_>
_<_a_c_t_i_o_n_>
Similar to aacccceessss--ccoonnttrrooll--ttaagg--aaccttiioonn:: but for interfaces.
Note that the interface needs to be already specified with
iinntteerrffaaccee:: and that any aacccceessss--ccoonnttrrooll**:: setting overrides all
iinntteerrffaaccee--**:: settings for targeted clients.
iinntteerrffaaccee--ttaagg--ddaattaa:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_> _<_t_a_g_>
_<_"_r_e_s_o_u_r_c_e _r_e_c_o_r_d _s_t_r_i_n_g_"_>
Similar to aacccceessss--ccoonnttrrooll--ttaagg--ddaattaa:: but for interfaces.
Note that the interface needs to be already specified with
iinntteerrffaaccee:: and that any aacccceessss--ccoonnttrrooll**:: setting overrides all
iinntteerrffaaccee--**:: settings for targeted clients.
iinntteerrffaaccee--vviieeww:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _[_@_p_o_r_t_]_> _<_v_i_e_w _n_a_m_e_>
Similar to aacccceessss--ccoonnttrrooll--vviieeww:: but for interfaces.
Note that the interface needs to be already specified with
iinntteerrffaaccee:: and that any aacccceessss--ccoonnttrrooll**:: setting overrides all
iinntteerrffaaccee--**:: settings for targeted clients.
cchhrroooott:: _<_d_i_r_e_c_t_o_r_y_>
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. Note that Unbound is not able to remove
the pidfile after termination when it is located outside of the
chroot directory.
Additionally, Unbound may need to access /dev/urandom (for
entropy) from inside the chroot.
If given a chroot is done to the given directory. By default
chroot is enabled and the default is "/var/unbound". If you give
"" no chroot is performed.
uusseerrnnaammee:: _<_n_a_m_e_>
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.
ddiirreeccttoorryy:: _<_d_i_r_e_c_t_o_r_y_>
Sets the working directory for the program. Default is
"/var/unbound/etc". 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.
llooggffiillee:: _<_f_i_l_e_n_a_m_e_>
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.
uussee--ssyysslloogg:: _<_y_e_s _o_r _n_o_>
Sets Unbound to send log messages to the syslogd, using _s_y_s_l_o_g(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.
lloogg--iiddeennttiittyy:: _<_s_t_r_i_n_g_>
If "" is given (default), then the name of the executable, usually
"unbound" is used to report to the log. Enter a string to
override it with that, which is useful on systems that run more
than one instance of Unbound, with different configurations, so
that the logs can be easily distinguished against.
lloogg--ttiimmee--aasscciiii:: _<_y_e_s _o_r _n_o_>
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.
lloogg--qquueerriieess:: _<_y_e_s _o_r _n_o_>
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
(significantly) slower. Odd (nonprintable) characters in names
are printed as '?'.
lloogg--rreepplliieess:: _<_y_e_s _o_r _n_o_>
Prints one line per reply to the log, with the log timestamp and
IP address, name, type, class, return code, time to resolve, from
cache and response size. Default is no. Note that it takes time
to print these lines which makes the server (significantly)
slower. Odd (nonprintable) characters in names are printed as
'?'.
lloogg--ttaagg--qquueerryyrreeppllyy:: _<_y_e_s _o_r _n_o_>
Prints the word 'query' and 'reply' with log-queries and
log-replies. This makes filtering logs easier. The default is
off (for backwards compatibility).
lloogg--llooccaall--aaccttiioonnss:: _<_y_e_s _o_r _n_o_>
Print log lines to inform about local zone actions. These lines
are like the local-zone type inform prints out, but they are also
printed for the other types of local zones.
lloogg--sseerrvvffaaiill:: _<_y_e_s _o_r _n_o_>
Print log lines that say why queries return SERVFAIL to clients.
This is separate from the verbosity debug logs, much smaller, and
printed at the error level, not the info level of debug info from
verbosity.
ppiiddffiillee:: _<_f_i_l_e_n_a_m_e_>
The process id is written to the file. Default is to not write to
a file.
rroooott--hhiinnttss:: _<_f_i_l_e_n_a_m_e_>
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.
hhiiddee--iiddeennttiittyy:: _<_y_e_s _o_r _n_o_>
If enabled id.server and hostname.bind queries are refused.
iiddeennttiittyy:: _<_s_t_r_i_n_g_>
Set the identity to report. If set to "", the default, then the
hostname of the server is returned.
hhiiddee--vveerrssiioonn:: _<_y_e_s _o_r _n_o_>
If enabled version.server and version.bind queries are refused.
vveerrssiioonn:: _<_s_t_r_i_n_g_>
Set the version to report. If set to "", the default, then the
package version is returned.
hhiiddee--hhttttpp--uusseerr--aaggeenntt:: _<_y_e_s _o_r _n_o_>
If enabled the HTTP header User-Agent is not set. Use with caution
as some webserver configurations may reject HTTP requests lacking
this header. If needed, it is better to explicitly set the
hhttttpp--uusseerr--aaggeenntt below.
hhttttpp--uusseerr--aaggeenntt:: _<_s_t_r_i_n_g_>
Set the HTTP User-Agent header for outgoing HTTP requests. If set
to "", the default, then the package name and version are used.
nnssiidd:: <string>
Add the specified nsid to the EDNS section of the answer when
queried with an NSID EDNS enabled packet. As a sequence of hex
characters or with ascii_ prefix and then an ascii string.
hhiiddee--ttrruussttaanncchhoorr:: _<_y_e_s _o_r _n_o_>
If enabled trustanchor.unbound queries are refused.
ttaarrggeett--ffeettcchh--ppoolliiccyy:: _<_"_l_i_s_t _o_f _n_u_m_b_e_r_s_"_>
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.
hhaarrddeenn--sshhoorrtt--bbuuffssiizzee:: _<_y_e_s _o_r _n_o_>
Very small EDNS buffer sizes from queries are ignored. Default is
on, as described in the standard.
hhaarrddeenn--llaarrggee--qquueerriieess:: _<_y_e_s _o_r _n_o_>
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.
hhaarrddeenn--gglluuee:: _<_y_e_s _o_r _n_o_>
Will trust glue only if it is within the servers authority.
Default is yes.
hhaarrddeenn--ddnnsssseecc--ssttrriippppeedd:: _<_y_e_s _o_r _n_o_>
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 yes.
hhaarrddeenn--bbeellooww--nnxxddoommaaiinn:: _<_y_e_s _o_r _n_o_>
From RFC 8020 (with title "NXDOMAIN: There Really Is Nothing
Underneath"), returns nxdomain to queries for a name below another
name that is already known to be nxdomain. 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 yes. The nxdomain must be secure, this means nsec3
with optout is insufficient.
hhaarrddeenn--rreeffeerrrraall--ppaatthh:: _<_y_e_s _o_r _n_o_>
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 no,
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
target-fetch-policy to increase the max depth that is checked to.
hhaarrddeenn--aallggoo--ddoowwnnggrraaddee:: _<_y_e_s _o_r _n_o_>
Harden against algorithm downgrade when multiple algorithms are
advertised in the DS record. If no, allows the weakest algorithm
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.
hhaarrddeenn--uunnkknnoowwnn--aaddddiittiioonnaall:: _<_y_e_s _o_r _n_o_>
Harden against unknown records in the authority section and
additional section. Default is no. If no, such records are copied
from the upstream and presented to the client together with the
answer. If yes, it could hamper future protocol developments that
want to add records.
uussee--ccaappss--ffoorr--iidd:: _<_y_e_s _o_r _n_o_>
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.
ccaappss--eexxeemmpptt:: _<_d_o_m_a_i_n_>
Exempt 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 answers,
like some load balancers. Can be given multiple times, for
different domains.
ccaappss--wwhhiitteelliisstt:: _<_y_e_s _o_r _n_o_>
Alternate syntax for ccaappss--eexxeemmpptt.
qqnnaammee--mmiinniimmiissaattiioonn:: _<_y_e_s _o_r _n_o_>
Send minimum amount of information to upstream servers to enhance
privacy. Only send minimum required labels of the QNAME and set
QTYPE to A when possible. Best effort approach; full QNAME and
original QTYPE will be sent when upstream replies with a RCODE
other than NOERROR, except when receiving NXDOMAIN from a DNSSEC
signed zone. Default is yes.
qqnnaammee--mmiinniimmiissaattiioonn--ssttrriicctt:: _<_y_e_s _o_r _n_o_>
QNAME minimisation in strict mode. Do not fall-back to sending
full QNAME to potentially broken nameservers. A lot of domains
will not be resolvable when this option in enabled. Only use if
you know what you are doing. This option only has effect when
qname-minimisation is enabled. Default is no.
aaggggrreessssiivvee--nnsseecc:: _<_y_e_s _o_r _n_o_>
Aggressive NSEC uses the DNSSEC NSEC chain to synthesize NXDOMAIN
and other denials, using information from previous NXDOMAINs
answers. Default is yes. It helps to reduce the query rate
towards targets that get a very high nonexistent name lookup rate.
pprriivvaattee--aaddddrreessss:: _<_I_P _a_d_d_r_e_s_s _o_r _s_u_b_n_e_t_>
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 occurrence 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 llooccaall--ddaattaa that
you configured is allowed to, and you can specify additional names
using pprriivvaattee--ddoommaaiinn. 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
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 spamblocklists as they
use that. Adding ::ffff:0:0/96 stops IPv4-mapped IPv6 addresses
from bypassing the filter.
pprriivvaattee--ddoommaaiinn:: _<_d_o_m_a_i_n _n_a_m_e_>
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.
uunnwwaanntteedd--rreeppllyy--tthhrreesshhoolldd:: _<_n_u_m_b_e_r_>
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).
ddoo--nnoott--qquueerryy--aaddddrreessss:: _<_I_P _a_d_d_r_e_s_s_>
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.
ddoo--nnoott--qquueerryy--llooccaallhhoosstt:: _<_y_e_s _o_r _n_o_>
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.
pprreeffeettcchh:: _<_y_e_s _o_r _n_o_>
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.
pprreeffeettcchh--kkeeyy:: _<_y_e_s _o_r _n_o_>
If yes, fetch the DNSKEYs earlier in the validation process, when
a DS record is encountered. This lowers the latency of requests.
It does use a little more CPU. Also if the cache is set to 0, it
is no use. Default is no.
ddeennyy--aannyy:: _<_y_e_s _o_r _n_o_>
If yes, deny queries of type ANY with an empty response. Default
is no. If disabled, Unbound responds with a short list of
resource records if some can be found in the cache and makes the
upstream type ANY query if there are none.
rrrrsseett--rroouunnddrroobbiinn:: _<_y_e_s _o_r _n_o_>
If yes, Unbound rotates RRSet order in response (the random number
is taken from the query ID, for speed and thread safety). Default
is yes.
mmiinniimmaall--rreessppoonnsseess:: _<_y_e_s _o_r _n_o_>
If yes, Unbound does not 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 yes, even though the DNS protocol RFCs mandate these sections,
and the additional content could be of use and save roundtrips for
clients. Because they are not used, and the saved roundtrips are
easier saved with prefetch, whilst this is faster.
ddiissaabbllee--ddnnsssseecc--llaammee--cchheecckk:: _<_y_e_s _o_r _n_o_>
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 unexpectedly
missing. The validator will insist in RRSIGs for DNSSEC signed
domains regardless of this setting, if a trust anchor is loaded.
mmoodduullee--ccoonnffiigg:: _<_"_m_o_d_u_l_e _n_a_m_e_s_"_>
Module configuration, a list of module names separated by spaces,
surround the string with quotes (""). The modules can be _r_e_s_p_i_p,
_v_a_l_i_d_a_t_o_r, or _i_t_e_r_a_t_o_r (and possibly more, see below). Setting
this to just "_i_t_e_r_a_t_o_r" will result in a non-validating server.
Setting this to "_v_a_l_i_d_a_t_o_r _i_t_e_r_a_t_o_r" will turn on DNSSEC
validation. The ordering of the modules is significant, the order
decides the order of processing. You must also set _t_r_u_s_t_-_a_n_c_h_o_r_s
for validation to be useful. Adding _r_e_s_p_i_p to the front will
cause RPZ processing to be done on all queries. The default is
"_v_a_l_i_d_a_t_o_r _i_t_e_r_a_t_o_r".
When the server is built with EDNS client subnet support the
default is "_s_u_b_n_e_t_c_a_c_h_e _v_a_l_i_d_a_t_o_r _i_t_e_r_a_t_o_r". Most modules that
need to be listed here have to be listed at the beginning of the
line. The subnetcachedb module has to be listed just before the
iterator. The python module can be listed in different places, it
then processes the output of the module it is just before. The
dynlib module can be listed pretty much anywhere, it is only a
very thin wrapper that allows dynamic libraries to run in its
place.
ttrruusstt--aanncchhoorr--ffiillee:: _<_f_i_l_e_n_a_m_e_>
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.
aauuttoo--ttrruusstt--aanncchhoorr--ffiillee:: _<_f_i_l_e_n_a_m_e_>
File with trust anchor for one zone, which is tracked with RFC5011
probes. The probes are run several times per month, thus the
machine must be online frequently. The initial file can be one
with contents as described in ttrruusstt--aanncchhoorr--ffiillee. 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), it must also be
inside the chroot (if that is used).
ttrruusstt--aanncchhoorr:: _<_"_R_e_s_o_u_r_c_e _R_e_c_o_r_d_"_>
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.
ttrruusstteedd--kkeeyyss--ffiillee:: _<_f_i_l_e_n_a_m_e_>
File with trusted keys for validation. Specify more than one file
with several entries, one file per entry. Like ttrruusstt--aanncchhoorr--ffiillee
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.
ttrruusstt--aanncchhoorr--ssiiggnnaalliinngg:: _<_y_e_s _o_r _n_o_>
Send RFC8145 key tag query after trust anchor priming. Default is
no.
rroooott--kkeeyy--sseennttiinneell:: _<_y_e_s _o_r _n_o_>
Root key trust anchor sentinel. Default is yes.
ddoommaaiinn--iinnsseeccuurree:: _<_d_o_m_a_i_n _n_a_m_e_>
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. 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.
vvaall--oovveerrrriiddee--ddaattee:: _<_r_r_s_i_g_-_s_t_y_l_e _d_a_t_e _s_p_e_c_>
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. The value -1 ignores the date
altogether, useful for some special applications.
vvaall--ssiigg--sskkeeww--mmiinn:: _<_s_e_c_o_n_d_s_>
Minimum number of seconds of clock skew to apply to validated
signatures. A value of 10% of the signature lifetime (expiration
- 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 signatures.
vvaall--ssiigg--sskkeeww--mmaaxx:: _<_s_e_c_o_n_d_s_>
Maximum number of seconds of clock skew to apply to validated
signatures. A value of 10% of the signature lifetime (expiration
- 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.
vvaall--mmaaxx--rreessttaarrtt:: _<_n_u_m_b_e_r_>
The maximum number the validator should restart validation with
another authority in case of failed validation. Default is 5.
vvaall--bboogguuss--ttttll:: _<_n_u_m_b_e_r_>
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.
vvaall--cclleeaann--aaddddiittiioonnaall:: _<_y_e_s _o_r _n_o_>
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 potentially bad data in the
additional section.
vvaall--lloogg--lleevveell:: _<_n_u_m_b_e_r_>
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. 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.
vvaall--ppeerrmmiissssiivvee--mmooddee:: _<_y_e_s _o_r _n_o_>
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".
iiggnnoorree--ccdd--ffllaagg:: _<_y_e_s _o_r _n_o_>
Instruct Unbound to ignore the CD flag from clients and refuse to
return bogus answers to them. Thus, the CD (Checking Disabled)
flag does not disable checking any more. This is useful if legacy
(w2008) servers that set the CD flag but cannot validate DNSSEC
themselves are the clients, and then Unbound provides them with
DNSSEC protection. The default value is "no".
sseerrvvee--eexxppiirreedd:: _<_y_e_s _o_r _n_o_>
If enabled, Unbound attempts to serve old responses from cache
with a TTL of sseerrvvee--eexxppiirreedd--rreeppllyy--ttttll in the response without
waiting for the actual resolution to finish. The actual
resolution answer ends up in the cache later on. Default is "no".
sseerrvvee--eexxppiirreedd--ttttll:: _<_s_e_c_o_n_d_s_>
Limit serving of expired responses to configured seconds after
expiration. 0 disables the limit. This option only applies when
sseerrvvee--eexxppiirreedd is enabled. A suggested value per RFC 8767 is
between 86400 (1 day) and 259200 (3 days). The default is 0.
sseerrvvee--eexxppiirreedd--ttttll--rreesseett:: _<_y_e_s _o_r _n_o_>
Set the TTL of expired records to the sseerrvvee--eexxppiirreedd--ttttll value
after a failed attempt to retrieve the record from upstream. This
makes sure that the expired records will be served as long as
there are queries for it. Default is "no".
sseerrvvee--eexxppiirreedd--rreeppllyy--ttttll:: _<_s_e_c_o_n_d_s_>
TTL value to use when replying with expired data. If
sseerrvvee--eexxppiirreedd--cclliieenntt--ttiimmeeoouutt is also used then it is RECOMMENDED
to use 30 as the value (RFC 8767). The default is 30.
sseerrvvee--eexxppiirreedd--cclliieenntt--ttiimmeeoouutt:: _<_m_s_e_c_>
Time in milliseconds before replying to the client with expired
data. This essentially enables the serve-stale behavior as
specified in RFC 8767 that first tries to resolve before
immediately responding with expired data. A recommended value per
RFC 8767 is 1800. Setting this to 0 will disable this behavior.
Default is 0.
sseerrvvee--oorriiggiinnaall--ttttll:: _<_y_e_s _o_r _n_o_>
If enabled, Unbound will always return the original TTL as
received from the upstream name server rather than the
decrementing TTL as stored in the cache. This feature may be
useful if Unbound serves as a front-end to a hidden authoritative
name server. Enabling this feature does not impact cache expiry,
it only changes the TTL Unbound embeds in responses to queries.
Note that enabling this feature implicitly disables enforcement of
the configured minimum and maximum TTL, as it is assumed users who
enable this feature do not want Unbound to change the TTL obtained
from an upstream server. Thus, the values set using ccaacchhee--mmiinn--ttttll
and ccaacchhee--mmaaxx--ttttll are ignored. Default is "no".
vvaall--nnsseecc33--kkeeyyssiizzee--iitteerraattiioonnss:: _<_"_l_i_s_t _o_f _v_a_l_u_e_s_"_>
List of keysize and iteration count values, separated by spaces,
surrounded by quotes. Default is "1024 150 2048 150 4096 150".
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.
zzoonneemmdd--ppeerrmmiissssiivvee--mmooddee:: _<_y_e_s _o_r _n_o_>
If enabled the ZONEMD verification failures are only logged and do
not cause the zone to be blocked and only return servfail. Useful
for testing out if it works, or if the operator only wants to be
notified of a problem without disrupting service. Default is no.
aadddd--hhoollddddoowwnn:: _<_s_e_c_o_n_d_s_>
Instruct the aauuttoo--ttrruusstt--aanncchhoorr--ffiillee 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.
ddeell--hhoollddddoowwnn:: _<_s_e_c_o_n_d_s_>
Instruct the aauuttoo--ttrruusstt--aanncchhoorr--ffiillee 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.
kkeeeepp--mmiissssiinngg:: _<_s_e_c_o_n_d_s_>
Instruct the aauuttoo--ttrruusstt--aanncchhoorr--ffiillee 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.
ppeerrmmiitt--ssmmaallll--hhoollddddoowwnn:: _<_y_e_s _o_r _n_o_>
Debug option that allows the autotrust 5011 rollover timers to
assume very small values. Default is no.
kkeeyy--ccaacchhee--ssiizzee:: _<_n_u_m_b_e_r_>
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).
kkeeyy--ccaacchhee--ssllaabbss:: _<_n_u_m_b_e_r_>
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.
nneegg--ccaacchhee--ssiizzee:: _<_n_u_m_b_e_r_>
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).
uunnbblloocckk--llaann--zzoonneess:: _<_y_e_s _o_r _n_o_>
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 network
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.
iinnsseeccuurree--llaann--zzoonneess:: _<_y_e_s _o_r _n_o_>
Default is disabled. If enabled, then reverse lookups in private
address space are not validated. This is usually required
whenever _u_n_b_l_o_c_k_-_l_a_n_-_z_o_n_e_s is used.
llooccaall--zzoonnee:: _<_z_o_n_e_> _<_t_y_p_e_>
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, typetransparent, inform,
inform_deny, inform_redirect, always_transparent, block_a,
always_refuse, always_nxdomain, always_null, noview, 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. A stub-zone can be used to have unbound send queries to
another server, an authoritative server, to fetch the information.
With a forward-zone, unbound sends queries to a server that is a
recursive server to fetch the information. With an auth-zone a
zone can be loaded from file and used, it can be used like a
local-zone for users downstream, or the auth-zone information can
be used to fetch information from when resolving like it is an
upstream server. The forward-zone and auth-zone options are
described in their sections below. If you want to perform
filtering of the information that the users can fetch, the
local-zone and local-data statements allow for this, but also the
rpz functionality can be used, described in the RPZ section.
_d_e_n_y Do not send an answer, drop the query. If there is a match
from local data, the query is answered.
_r_e_f_u_s_e
Send an error message reply, with rcode REFUSED. If there is a
match from local data, the query is answered.
_s_t_a_t_i_c
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.
_t_r_a_n_s_p_a_r_e_n_t
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.
_t_y_p_e_t_r_a_n_s_p_a_r_e_n_t
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.
_r_e_d_i_r_e_c_t
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 return a different address record to the end user, 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, so that users with web
browsers cannot access sites with suffix example.com.
_i_n_f_o_r_m
The query is answered normally, same as transparent. The
client IP address (@portnumber) is printed to the logfile. The
log message is: timestamp, unbound-pid, info: zonename inform
IP@port queryname type class. This option can be used for
normal resolution, but machines looking up infected names are
logged, eg. to run antivirus on them.
_i_n_f_o_r_m___d_e_n_y
The query is dropped, like 'deny', and logged, like 'inform'.
Ie. find infected machines without answering the queries.
_i_n_f_o_r_m___r_e_d_i_r_e_c_t
The query is redirected, like 'redirect', and logged, like
'inform'. Ie. answer queries with fixed data and also log the
machines that ask.
_a_l_w_a_y_s___t_r_a_n_s_p_a_r_e_n_t
Like transparent, but ignores local data and resolves normally.
_b_l_o_c_k___a
Like transparent, but ignores local data and resolves normally
all query types excluding A. For A queries it unconditionally
returns NODATA. Useful in cases when there is a need to
explicitly force all apps to use IPv6 protocol and avoid any
queries to IPv4.
_a_l_w_a_y_s___r_e_f_u_s_e
Like refuse, but ignores local data and refuses the query.
_a_l_w_a_y_s___n_x_d_o_m_a_i_n
Like static, but ignores local data and returns nxdomain for
the query.
_a_l_w_a_y_s___n_o_d_a_t_a
Like static, but ignores local data and returns nodata for the
query.
_a_l_w_a_y_s___d_e_n_y
Like deny, but ignores local data and drops the query.
_a_l_w_a_y_s___n_u_l_l
Always returns 0.0.0.0 or ::0 for every name in the zone. Like
redirect with zero data for A and AAAA. Ignores local data in
the zone. Used for some block lists.
_n_o_v_i_e_w
Breaks out of that view and moves towards the global local
zones for answer to the query. If the view first is no, it'll
resolve normally. If view first is enabled, it'll break
perform that step and check the global answers. For when the
view has view specific overrides but some zone has to be
answered from global local zone contents.
_n_o_d_e_f_a_u_l_t
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. Use _n_o_d_e_f_a_u_l_t if you use exactly
that zone, if you want to use a subzone, use _t_r_a_n_s_p_a_r_e_n_t.
The default zones are localhost, reverse 127.0.0.1 and ::1, the
home.arpa, the onion, test, invalid 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.
_l_o_c_a_l_h_o_s_t
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." redirect
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"
_r_e_v_e_r_s_e _I_P_v_4 _l_o_o_p_b_a_c_k
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."
_r_e_v_e_r_s_e _I_P_v_6 _l_o_o_p_b_a_c_k
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."
_h_o_m_e_._a_r_p_a _(_R_F_C _8_3_7_5_)
Default content:
local-zone: "home.arpa." static
local-data: "home.arpa. 10800 IN NS localhost."
local-data: "home.arpa. 10800 IN
SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
_o_n_i_o_n _(_R_F_C _7_6_8_6_)
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"
_t_e_s_t _(_R_F_C _6_7_6_1_)
Default content:
local-zone: "test." static
local-data: "test. 10800 IN NS localhost."
local-data: "test. 10800 IN
SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
_i_n_v_a_l_i_d _(_R_F_C _6_7_6_1_)
Default content:
local-zone: "invalid." static
local-data: "invalid. 10800 IN NS localhost."
local-data: "invalid. 10800 IN
SOA localhost. nobody.invalid. 1 3600 1200 604800 10800"
_r_e_v_e_r_s_e _R_F_C_1_9_1_8 _l_o_c_a_l _u_s_e _z_o_n_e_s
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 llooccaall--zzoonnee:: is
set static and as llooccaall--ddaattaa:: SOA and NS records are provided.
_r_e_v_e_r_s_e _R_F_C_3_3_3_0 _I_P_4 _t_h_i_s_, _l_i_n_k_-_l_o_c_a_l_, _t_e_s_t_n_e_t _a_n_d _b_r_o_a_d_c_a_s_t
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).
_r_e_v_e_r_s_e _R_F_C_4_2_9_1 _I_P_6 _u_n_s_p_e_c_i_f_i_e_d
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.
_r_e_v_e_r_s_e _R_F_C_4_1_9_3 _I_P_v_6 _L_o_c_a_l_l_y _A_s_s_i_g_n_e_d _L_o_c_a_l _A_d_d_r_e_s_s_e_s
Reverse data for zone D.F.ip6.arpa.
_r_e_v_e_r_s_e _R_F_C_4_2_9_1 _I_P_v_6 _L_i_n_k _L_o_c_a_l _A_d_d_r_e_s_s_e_s
Reverse data for zones 8.E.F.ip6.arpa to B.E.F.ip6.arpa.
_r_e_v_e_r_s_e _I_P_v_6 _E_x_a_m_p_l_e _P_r_e_f_i_x
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.
llooccaall--ddaattaa:: _"_<_r_e_s_o_u_r_c_e _r_e_c_o_r_d _s_t_r_i_n_g_>_"
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.
llooccaall--ddaattaa--ppttrr:: _"_I_P_a_d_d_r _n_a_m_e_"
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"
llooccaall--zzoonnee--ttaagg:: _<_z_o_n_e_> _<_"_l_i_s_t _o_f _t_a_g_s_"_>
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 _d_e_f_i_n_e_-_t_a_g_s. Enclose list of tags in quotes ("") and
put spaces between tags. When there are multiple tags it checks if
the intersection of the list of tags for the query and
local-zone-tag is non-empty.
llooccaall--zzoonnee--oovveerrrriiddee:: _<_z_o_n_e_> _<_I_P _n_e_t_b_l_o_c_k_> _<_t_y_p_e_>
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.
rreessppoonnssee--iipp:: _<_I_P_-_n_e_t_b_l_o_c_k_> _<_a_c_t_i_o_n_>
This requires use of the "respip" module.
If the IP address in an AAAA or A RR in the answer section of a
response matches the specified IP netblock, the specified action
will apply. _<_a_c_t_i_o_n_> has generally the same semantics as that for
_a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g_-_a_c_t_i_o_n, but there are some exceptions.
Actions for _r_e_s_p_o_n_s_e_-_i_p are different from those for _l_o_c_a_l_-_z_o_n_e in
that in case of the former there is no point of such conditions as
"the query matches it but there is no local data". Because of this
difference, the semantics of _r_e_s_p_o_n_s_e_-_i_p actions are modified or
simplified as follows: The _s_t_a_t_i_c_, _r_e_f_u_s_e_, _t_r_a_n_s_p_a_r_e_n_t_,
_t_y_p_e_t_r_a_n_s_p_a_r_e_n_t_, and _n_o_d_e_f_a_u_l_t actions are invalid for _r_e_s_p_o_n_s_e_-_i_p.
Using any of these will cause the configuration to be rejected as
faulty. The _d_e_n_y action is non-conditional, i.e. it always results
in dropping the corresponding query. The resolution result before
applying the deny action is still cached and can be used for other
queries.
rreessppoonnssee--iipp--ddaattaa:: _<_I_P_-_n_e_t_b_l_o_c_k_> _<_"_r_e_s_o_u_r_c_e _r_e_c_o_r_d _s_t_r_i_n_g_"_>
This requires use of the "respip" module.
This specifies the action data for _r_e_s_p_o_n_s_e_-_i_p with action being to
redirect as specified by "_r_e_s_o_u_r_c_e _r_e_c_o_r_d _s_t_r_i_n_g". "Resource record
string" is similar to that of _a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g_-_a_c_t_i_o_n, but it must
be of either AAAA, A or CNAME types. If the IP-netblock is an
IPv6/IPv4 prefix, the record must be AAAA/A respectively, unless it
is a CNAME (which can be used for both versions of IP netblocks).
If it is CNAME there must not be more than one _r_e_s_p_o_n_s_e_-_i_p_-_d_a_t_a for
the same IP-netblock. Also, CNAME and other types of records must
not coexist for the same IP-netblock, following the normal rules for
CNAME records. The textual domain name for the CNAME does not have
to be explicitly terminated with a dot ("."); the root name is
assumed to be the origin for the name.
rreessppoonnssee--iipp--ttaagg:: _<_I_P_-_n_e_t_b_l_o_c_k_> _<_"_l_i_s_t _o_f _t_a_g_s_"_>
This requires use of the "respip" module.
Assign tags to response IP-netblocks. If the IP address in an AAAA
or A RR in the answer section of a response matches the specified
IP-netblock, the specified tags are assigned to the IP address.
Then, if an _a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g is defined for the client and it
includes one of the tags for the response IP, the corresponding
_a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g_-_a_c_t_i_o_n will apply. Tag matching rule is the same
as that for _a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g and _l_o_c_a_l_-_z_o_n_e_s. Unlike _l_o_c_a_l_-_z_o_n_e_-
_t_a_g, _r_e_s_p_o_n_s_e_-_i_p_-_t_a_g can be defined for an IP-netblock even if no
_r_e_s_p_o_n_s_e_-_i_p is defined for that netblock. If multiple _r_e_s_p_o_n_s_e_-_i_p_-
_t_a_g options are specified for the same IP-netblock in different
statements, all but the first will be ignored. However, this will
not be flagged as a configuration error, but the result is probably
not what was intended.
Actions specified in an _a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g_-_a_c_t_i_o_n that has a
matching tag with _r_e_s_p_o_n_s_e_-_i_p_-_t_a_g can be those that are "invalid"
for _r_e_s_p_o_n_s_e_-_i_p listed above, since _a_c_c_e_s_s_-_c_o_n_t_r_o_l_-_t_a_g_-_a_c_t_i_o_ns can
be shared with local zones. For these actions, if they behave
differently depending on whether local data exists or not in case of
local zones, the behavior for _r_e_s_p_o_n_s_e_-_i_p_-_d_a_t_a will generally result
in NOERROR/NODATA instead of NXDOMAIN, since the _r_e_s_p_o_n_s_e_-_i_p data
are inherently type specific, and non-existence of data does not
indicate anything about the existence or non-existence of the qname
itself. For example, if the matching tag action is _s_t_a_t_i_c but there
is no data for the corresponding _r_e_s_p_o_n_s_e_-_i_p configuration, then the
result will be NOERROR/NODATA. The only case where NXDOMAIN is
returned is when an _a_l_w_a_y_s___n_x_d_o_m_a_i_n action applies.
rraatteelliimmiitt:: _<_n_u_m_b_e_r _o_r _0_>
Enable ratelimiting of queries sent to nameserver for performing
recursion. If 0, the default, it is disabled. This option is
experimental 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
ratelimited 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.
Configured forwarders are excluded from ratelimiting.
rraatteelliimmiitt--ssiizzee:: _<_m_e_m_o_r_y _s_i_z_e_>
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.
rraatteelliimmiitt--ssllaabbss:: _<_n_u_m_b_e_r_>
Give power of 2 number of slabs, this is used to reduce lock
contention in the ratelimit tracking data structure. Close to the
number of cpus is a fairly good setting.
rraatteelliimmiitt--ffaaccttoorr:: _<_n_u_m_b_e_r_>
Set the amount of queries to rate limit when the limit is exceeded.
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 mitigating the
traffic flow by the factor given.
rraatteelliimmiitt--bbaacckkooffff:: _<_y_e_s _o_r _n_o_>
If enabled, the ratelimit is treated as a hard failure instead of
the default maximum allowed constant rate. When the limit is
reached, traffic is ratelimited and demand continues to be kept
track of for a 2 second rate window. No traffic is allowed, except
for ratelimit-factor, until demand decreases below the configured
ratelimit for a 2 second rate window. Useful to set ratelimit to a
suspicious rate to aggressively limit unusually high traffic.
Default is off.
rraatteelliimmiitt--ffoorr--ddoommaaiinn:: _<_d_o_m_a_i_n_> _<_n_u_m_b_e_r _q_p_s _o_r _0_>
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. A value of 0 will disable ratelimiting for that
domain.
rraatteelliimmiitt--bbeellooww--ddoommaaiinn:: _<_d_o_m_a_i_n_> _<_n_u_m_b_e_r _q_p_s _o_r _0_>
Override the global ratelimit for a domain name that ends in this
name. You can give this multiple times, it then describes different
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 ratelimit-for-domain to set
that, you might want to use different settings for a
top-level-domain and subdomains. A value of 0 will disable
ratelimiting for domain names that end in this name.
iipp--rraatteelliimmiitt:: _<_n_u_m_b_e_r _o_r _0_>
Enable global ratelimiting of queries accepted per IP address. This
option is experimental at this time. The ratelimit is in queries
per second that are allowed. More queries are completely dropped
and will not receive a reply, SERVFAIL or otherwise. IP
ratelimiting happens before looking in the cache. This may be useful
for mitigating amplification attacks. Default is 0 (disabled).
iipp--rraatteelliimmiitt--ccooookkiiee:: _<_n_u_m_b_e_r _o_r _0_>
Enable global ratelimiting of queries accepted per IP address with a
valid DNS Cookie. This option is experimental at this time. The
ratelimit is in queries per second that are allowed. More queries
are completely dropped and will not receive a reply, SERVFAIL or
otherwise. IP ratelimiting happens before looking in the cache.
This option could be useful in combination with _a_l_l_o_w___c_o_o_k_i_e in an
attempt to mitigate other amplification attacks than UDP reflections
(e.g., attacks targeting Unbound itself) which are already handled
with DNS Cookies. If used, the value is suggested to be higher than
iipp--rraatteelliimmiitt e.g., tenfold. Default is 0 (disabled).
iipp--rraatteelliimmiitt--ssiizzee:: _<_m_e_m_o_r_y _s_i_z_e_>
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 ip ratelimit structure is small, so this data
structure likely does not need to be large.
iipp--rraatteelliimmiitt--ssllaabbss:: _<_n_u_m_b_e_r_>
Give power of 2 number of slabs, this is used to reduce lock
contention in the ip ratelimit tracking data structure. Close to
the number of cpus is a fairly good setting.
iipp--rraatteelliimmiitt--ffaaccttoorr:: _<_n_u_m_b_e_r_>
Set the amount of queries to rate limit when the limit is exceeded.
If set to 0, all queries are dropped for addresses 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 mitigating the
traffic flow by the factor given.
iipp--rraatteelliimmiitt--bbaacckkooffff:: _<_y_e_s _o_r _n_o_>
If enabled, the ratelimit is treated as a hard failure instead of
the default maximum allowed constant rate. When the limit is
reached, traffic is ratelimited and demand continues to be kept
track of for a 2 second rate window. No traffic is allowed, except
for ip-ratelimit-factor, until demand decreases below the configured
ratelimit for a 2 second rate window. Useful to set ip-ratelimit to
a suspicious rate to aggressively limit unusually high traffic.
Default is off.
oouuttbboouunndd--mmssgg--rreettrryy:: _<_n_u_m_b_e_r_>
The number of retries, per upstream nameserver in a delegation, that
Unbound will attempt in case a throwaway response is received. No
response (timeout) contributes to the retry counter. If a
forward/stub zone is used, this is the number of retries per
nameserver in the zone. Default is 5.
mmaaxx--sseenntt--ccoouunntt:: _<_n_u_m_b_e_r_>
Hard limit on the number of outgoing queries Unbound will make while
resolving a name, making sure large NS sets do not loop. Results in
SERVFAIL when reached. It resets on query restarts (e.g., CNAME)
and referrals. Default is 32.
mmaaxx--qquueerryy--rreessttaarrttss:: _<_n_u_m_b_e_r_>
Hard limit on the number of times Unbound is allowed to restart a
query upon encountering a CNAME record. Results in SERVFAIL when
reached. Changing this value needs caution as it can allow long
CNAME chains to be accepted, where Unbound needs to verify (resolve)
each link individually. Default is 11.
ffaasstt--sseerrvveerr--ppeerrmmiill:: _<_n_u_m_b_e_r_>
Specify how many times out of 1000 to pick from the set of fastest
servers. 0 turns the feature off. A value of 900 would pick from
the fastest servers 90 percent of the time, and would perform normal
exploration of random servers for the remaining time. When prefetch
is enabled (or serve-expired), such prefetches are not sped up,
because there is no one waiting for it, and it presents a good
moment to perform server exploration. The ffaasstt--sseerrvveerr--nnuumm option can
be used to specify the size of the fastest servers set. The default
for fast-server-permil is 0.
ffaasstt--sseerrvveerr--nnuumm:: _<_n_u_m_b_e_r_>
Set the number of servers that should be used for fast server
selection. Only use the fastest specified number of servers with the
fast-server-permil option, that turns this on or off. The default is
to use the fastest 3 servers.
aannsswweerr--ccooookkiiee:: _<_y_e_s _o_r _n_o_>
If enabled, Unbound will answer to requests containing DNS Cookies
as specified in RFC 7873 and RFC 9018. Default is no.
ccooookkiiee--sseeccrreett:: _<_1_2_8 _b_i_t _h_e_x _s_t_r_i_n_g_>
Server's secret for DNS Cookie generation. Useful to explicitly set
for servers in an anycast deployment that need to share the secret
in order to verify each other's Server Cookies. An example hex
string would be "000102030405060708090a0b0c0d0e0f". Default is a
128 bits random secret generated at startup time.
eeddnnss--cclliieenntt--ssttrriinngg:: _<_I_P _n_e_t_b_l_o_c_k_> _<_s_t_r_i_n_g_>
Include an EDNS0 option containing configured ascii string in
queries with destination address matching the configured IP
netblock. This configuration option can be used multiple times. The
most specific match will be used.
eeddnnss--cclliieenntt--ssttrriinngg--ooppccooddee:: _<_o_p_c_o_d_e_>
EDNS0 option code for the _e_d_n_s_-_c_l_i_e_n_t_-_s_t_r_i_n_g option, from 0 to
65535. A value from the `Reserved for Local/Experimental` range
(65001-65534) should be used. Default is 65001.
eeddee:: _<_y_e_s _o_r _n_o_>
If enabled, Unbound will respond with Extended DNS Error codes
(RFC8914). These EDEs attach informative error messages to a
response for various errors. Default is "no".
When the vvaall--lloogg--lleevveell option is also set to 22, responses with
Extended DNS Errors concerning DNSSEC failures that are not served
from cache, will also contain a descriptive text message about the
reason for the failure.
eeddee--sseerrvvee--eexxppiirreedd:: _<_y_e_s _o_r _n_o_>
If enabled, Unbound will attach an Extended DNS Error (RFC8914) Code
3 - Stale Answer as EDNS0 option to the expired response. Note that
this will not attach the EDE code without setting the global eeddee
option to "yes" as well. Default is "no".
RReemmoottee CCoonnttrrooll OOppttiioonnss In the rreemmoottee--ccoonnttrrooll:: clause are the declarations for the remote control facility. If this is enabled, the _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l(8) utility can be used to send commands to the running Unbound server. The server uses these clauses to setup TLSv1 security for the connection. The _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l(8) utility also reads the rreemmoottee--ccoonnttrrooll section for options. To setup the correct self-signed certificates use the _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l_-_s_e_t_u_p(8) utility.
ccoonnttrrooll--eennaabbllee:: _<_y_e_s _o_r _n_o_>
The option is used to enable remote control, default is "no". If
turned off, the server does not listen for control commands.
ccoonnttrrooll--iinntteerrffaaccee:: _<_i_p _a_d_d_r_e_s_s _o_r _i_n_t_e_r_f_a_c_e _n_a_m_e _o_r _p_a_t_h_>
Give IPv4 or IPv6 addresses or local socket path to listen on for
control commands. If an interface name is used instead of an ip
address, the list of ip addresses on that interface are used. 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.
If you set it to an absolute path, a unix domain socket is used.
This socket does not use the certificates and keys, so those files
need not be present. To restrict access, Unbound sets permissions
on the file to the user and group that is configured, the access
bits are set to allow the group members to access the control socket
file. Put users that need to access the socket in the that group.
To restrict access further, create a directory to put the control
socket in and restrict access to that directory.
ccoonnttrrooll--ppoorrtt:: _<_p_o_r_t _n_u_m_b_e_r_>
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 effect.
ccoonnttrrooll--uussee--cceerrtt:: _<_y_e_s _o_r _n_o_>
For localhost control-interface you can disable the use of TLS by
setting this option to "no", default is "yes". For local sockets,
TLS is disabled and the value of this option is ignored.
sseerrvveerr--kkeeyy--ffiillee:: _<_p_r_i_v_a_t_e _k_e_y _f_i_l_e_>
Path to the server private key, by default unbound_server.key. This
file is generated by the _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l_-_s_e_t_u_p utility. This file
is used by the Unbound server, but not by _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l.
sseerrvveerr--cceerrtt--ffiillee:: _<_c_e_r_t_i_f_i_c_a_t_e _f_i_l_e_._p_e_m_>
Path to the server self signed certificate, by default
unbound_server.pem. This file is generated by the
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l_-_s_e_t_u_p utility. This file is used by the Unbound
server, and also by _u_n_b_o_u_n_d_-_c_o_n_t_r_o_l.
ccoonnttrrooll--kkeeyy--ffiillee:: _<_p_r_i_v_a_t_e _k_e_y _f_i_l_e_>
Path to the control client private key, by default
unbound_control.key. This file is generated by the
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l_-_s_e_t_u_p utility. This file is used by
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l.
ccoonnttrrooll--cceerrtt--ffiillee:: _<_c_e_r_t_i_f_i_c_a_t_e _f_i_l_e_._p_e_m_>
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
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l_-_s_e_t_u_p utility. This file is used by
_u_n_b_o_u_n_d_-_c_o_n_t_r_o_l.
SSttuubb ZZoonnee OOppttiioonnss There may be multiple ssttuubb--zzoonnee:: 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 servers should be authority servers, not recursors; Unbound performs the recursive processing itself 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
authoritative server on a different host (or different port). Enter a
config entry for Unbound with ssttuubb--aaddddrr:: <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.
Consider adding sseerrvveerr:: statements for ddoommaaiinn--iinnsseeccuurree:: and for
llooccaall--zzoonnee:: _n_a_m_e _n_o_d_e_f_a_u_l_t for the zone if it is a locally served zone.
The insecure clause stops DNSSEC from invalidating the zone. The local
zone nodefault (or _t_r_a_n_s_p_a_r_e_n_t) clause makes the (reverse-) zone bypass
Unbound's filtering of RFC1918 zones.
nnaammee:: _<_d_o_m_a_i_n _n_a_m_e_>
Name of the stub zone. This is the full domain name of the zone.
ssttuubb--hhoosstt:: _<_d_o_m_a_i_n _n_a_m_e_>
Name of stub zone nameserver. Is itself resolved before it is
used. To use a nondefault port for DNS communication append '@'
with the port number. If tls is enabled, then you can append a
'#' and a name, then it'll check the tls authentication
certificates with that name. If you combine the '@' and '#', the
'@' comes first. If only '#' is used the default port is the
configured tls-port.
ssttuubb--aaddddrr:: _<_I_P _a_d_d_r_e_s_s_>
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. If tls is enabled, then you can append a '#' and a name,
then it'll check the tls authentication certificates with that
name. If you combine the '@' and '#', the '@' comes first. If
only '#' is used the default port is the configured tls-port.
ssttuubb--pprriimmee:: _<_y_e_s _o_r _n_o_>
This option is by default no. 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.
ssttuubb--ffiirrsstt:: _<_y_e_s _o_r _n_o_>
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.
ssttuubb--ttllss--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Enabled or disable whether the queries to this stub use TLS for
transport. Default is no.
ssttuubb--ssssll--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Alternate syntax for ssttuubb--ttllss--uuppssttrreeaamm.
ssttuubb--ttccpp--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
If it is set to "yes" then upstream queries use TCP only for
transport regardless of global flag tcp-upstream. Default is no.
ssttuubb--nnoo--ccaacchhee:: _<_y_e_s _o_r _n_o_>
Default is no. If enabled, data inside the stub is not cached.
This is useful when you want immediate changes to be visible.
FFoorrwwaarrdd ZZoonnee OOppttiioonnss There may be multiple ffoorrwwaarrdd--zzoonnee:: clauses. Each with a nnaammee:: 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 ffoorrwwaarrdd--hhoosstt:: and ffoorrwwaarrdd--aaddddrr:: 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. CNAMEs are chased by Unbound itself, asking the remote server for every name in the indirection chain, to protect the local cache from illegal indirect referenced items. 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).
nnaammee:: _<_d_o_m_a_i_n _n_a_m_e_>
Name of the forward zone. This is the full domain name of the
zone.
ffoorrwwaarrdd--hhoosstt:: _<_d_o_m_a_i_n _n_a_m_e_>
Name of server to forward to. Is itself resolved before it is
used. To use a nondefault port for DNS communication append '@'
with the port number. If tls is enabled, then you can append a
'#' and a name, then it'll check the tls authentication
certificates with that name. If you combine the '@' and '#', the
'@' comes first. If only '#' is used the default port is the
configured tls-port.
ffoorrwwaarrdd--aaddddrr:: _<_I_P _a_d_d_r_e_s_s_>
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. If tls is enabled, then you can append a '#' and a name,
then it'll check the tls authentication certificates with that
name. If you combine the '@' and '#', the '@' comes first. If
only '#' is used the default port is the configured tls-port.
At high verbosity it logs the TLS certificate, with TLS enabled.
If you leave out the '#' and auth name from the forward-addr, any
name is accepted. The cert must also match a CA from the
tls-cert-bundle.
ffoorrwwaarrdd--ffiirrsstt:: _<_y_e_s _o_r _n_o_>
If a forwarded query is met with a SERVFAIL error, and this option
is enabled, Unbound will fall back to normal recursive resolution
for this query as if no query forwarding had been specified. The
default is "no".
ffoorrwwaarrdd--ttllss--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Enabled or disable whether the queries to this forwarder use TLS
for transport. Default is no. If you enable this, also configure
a tls-cert-bundle or use tls-win-cert to load CA certs, otherwise
the connections cannot be authenticated.
ffoorrwwaarrdd--ssssll--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Alternate syntax for ffoorrwwaarrdd--ttllss--uuppssttrreeaamm.
ffoorrwwaarrdd--ttccpp--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
If it is set to "yes" then upstream queries use TCP only for
transport regardless of global flag tcp-upstream. Default is no.
ffoorrwwaarrdd--nnoo--ccaacchhee:: _<_y_e_s _o_r _n_o_>
Default is no. If enabled, data inside the forward is not cached.
This is useful when you want immediate changes to be visible.
AAuutthhoorriittyy ZZoonnee OOppttiioonnss Authority zones are configured with aauutthh--zzoonnee::, and each one must have a nnaammee::. There can be multiple ones, by listing multiple auth-zone clauses, each with a different name, pertaining to that part of the namespace. The authority zone with the name closest to the name looked up is used. Authority zones can be processed on two distinct, non- exclusive, configurable stages.
With ffoorr--ddoowwnnssttrreeaamm:: _y_e_s (default), authority zones are processed after
llooccaall--zzoonneess and before cache. When used in this manner, Unbound responds
like an authority server with no further processing other than returning
an answer from the zone contents. A notable example, in this case, is
CNAME records which are returned verbatim to downstream clients without
further resolution.
With ffoorr--uuppssttrreeaamm:: _y_e_s (default), authority zones are processed after the
cache lookup, just before going to the network to fetch information for
recursion. When used in this manner they provide a local copy of an
authority server that speeds up lookups for that data during resolving.
If both options are enabled (default), client queries for an authority
zone are answered authoritatively from Unbound, while internal queries
that require data from the authority zone consult the local zone data
instead of going to the network.
An interesting configuration is ffoorr--ddoowwnnssttrreeaamm:: _n_o, ffoorr--uuppssttrreeaamm:: _y_e_s
that allows for hyperlocal behavior where both client and internal
queries consult the local zone data while resolving. In this case, the
aforementioned CNAME example will result in a thoroughly resolved answer.
Authority zones can be read from zonefile. And can be kept updated via
AXFR and IXFR. After update the zonefile is rewritten. The update
mechanism uses the SOA timer values and performs SOA UDP queries to
detect zone changes.
If the update fetch fails, the timers in the SOA record are used to time
another fetch attempt. Until the SOA expiry timer is reached. Then the
zone is expired. When a zone is expired, queries are SERVFAIL, and any
new serial number is accepted from the primary (even if older), and if
fallback is enabled, the fallback activates to fetch from the upstream
instead of the SERVFAIL.
nnaammee:: _<_z_o_n_e _n_a_m_e_>
Name of the authority zone.
pprriimmaarryy:: _<_I_P _a_d_d_r_e_s_s _o_r _h_o_s_t _n_a_m_e_>
Where to download a copy of the zone from, with AXFR and IXFR.
Multiple primaries can be specified. They are all tried if one
fails. To use a nondefault port for DNS communication append '@'
with the port number. You can append a '#' and a name, then AXFR
over TLS can be used and the tls authentication certificates will
be checked with that name. If you combine the '@' and '#', the
'@' comes first. If you point it at another Unbound instance, it
would not work because that does not support AXFR/IXFR for the
zone, but if you used uurrll:: to download the zonefile as a text file
from a webserver that would work. If you specify the hostname,
you cannot use the domain from the zonefile, because it may not
have that when retrieving that data, instead use a plain IP
address to avoid a circular dependency on retrieving that IP
address.
mmaasstteerr:: _<_I_P _a_d_d_r_e_s_s _o_r _h_o_s_t _n_a_m_e_>
Alternate syntax for pprriimmaarryy.
uurrll:: _<_u_r_l _t_o _z_o_n_e_f_i_l_e_>
Where to download a zonefile for the zone. With http or https.
An example for the url is
"http://www.example.com/example.org.zone". Multiple url
statements can be given, they are tried in turn. If only urls are
given the SOA refresh timer is used to wait for making new
downloads. If also primaries are listed, the primaries are first
probed with UDP SOA queries to see if the SOA serial number has
changed, reducing the number of downloads. If none of the urls
work, the primaries are tried with IXFR and AXFR. For https, the
ttllss--cceerrtt--bbuunnddllee and the hostname from the url are used to
authenticate the connection. If you specify a hostname in the
URL, you cannot use the domain from the zonefile, because it may
not have that when retrieving that data, instead use a plain IP
address to avoid a circular dependency on retrieving that IP
address. Avoid dependencies on name lookups by using a notation
like "http://192.0.2.1/unbound-primaries/example.com.zone", with
an explicit IP address.
aallllooww--nnoottiiffyy:: _<_I_P _a_d_d_r_e_s_s _o_r _h_o_s_t _n_a_m_e _o_r _n_e_t_b_l_o_c_k_I_P_/_p_r_e_f_i_x_>
With allow-notify you can specify additional sources of notifies.
When notified, the server attempts to first probe and then zone
transfer. If the notify is from a primary, it first attempts that
primary. Otherwise other primaries are attempted. If there are
no primaries, but only urls, the file is downloaded when notified.
The primaries from primary: and url: statements are allowed notify
by default.
ffaallllbbaacckk--eennaabblleedd:: _<_y_e_s _o_r _n_o_>
Default no. If enabled, Unbound falls back to querying the
internet as a resolver for this zone when lookups fail. For
example for DNSSEC validation failures.
ffoorr--ddoowwnnssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Default yes. If enabled, Unbound serves authority responses to
downstream clients for this zone. This option makes Unbound
behave, for the queries with names in this zone, like one of the
authority servers for that zone. Turn it off if you want Unbound
to provide recursion for the zone but have a local copy of zone
data. If for-downstream is no and for-upstream is yes, then
Unbound will DNSSEC validate the contents of the zone before
serving the zone contents to clients and store validation results
in the cache.
ffoorr--uuppssttrreeaamm:: _<_y_e_s _o_r _n_o_>
Default yes. If enabled, Unbound fetches data from this data
collection for answering recursion queries. Instead of sending
queries over the internet to the authority servers for this zone,
it'll fetch the data directly from the zone data. Turn it on when
you want Unbound to provide recursion for downstream clients, and
use the zone data as a local copy to speed up lookups.
zzoonneemmdd--cchheecckk:: _<_y_e_s _o_r _n_o_>
Enable this option to check ZONEMD records in the zone. Default is
disabled. The ZONEMD record is a checksum over the zone data.
This includes glue in the zone and data from the zone file, and
excludes comments from the zone file. When there is a DNSSEC
chain of trust, DNSSEC signatures are checked too.
zzoonneemmdd--rreejjeecctt--aabbsseennccee:: _<_y_e_s _o_r _n_o_>
Enable this option to reject the absence of the ZONEMD record.
Without it, when zonemd is not there it is not checked. It is
useful to enable for a nonDNSSEC signed zone where the operator
wants to require the verification of a ZONEMD, hence a missing
ZONEMD is a failure. The action upon failure is controlled by the
zzoonneemmdd--ppeerrmmiissssiivvee--mmooddee option, for log only or also block the
zone. The default is no.
Without the option absence of a ZONEMD is only a failure when the
zone is DNSSEC signed, and we have a trust anchor, and the DNSSEC
verification of the absence of the ZONEMD fails. With the option
enabled, the absence of a ZONEMD is always a failure, also for
nonDNSSEC signed zones.
zzoonneeffiillee:: _<_f_i_l_e_n_a_m_e_>
The filename where the zone is stored. If not given then no
zonefile is used. If the file does not exist or is empty, Unbound
will attempt to fetch zone data (eg. from the primary servers).
VViieeww OOppttiioonnss There may be multiple vviieeww:: clauses. Each with a nnaammee:: and zero or more llooccaall--zzoonnee and llooccaall--ddaattaa elements. Views can also contain view-first, response-ip, response-ip-data and local-data-ptr elements. View can be mapped to requests by specifying the view name in an aacccceessss--ccoonnttrrooll--vviieeww element. Options from matching views will override global options. Global options will be used if no matching view is found, or when the matching view does not have the option specified.
nnaammee:: _<_v_i_e_w _n_a_m_e_>
Name of the view. Must be unique. This name is used in
access-control-view elements.
llooccaall--zzoonnee:: _<_z_o_n_e_> _<_t_y_p_e_>
View specific local-zone elements. Has the same types and
behaviour as the global local-zone elements. When there is at
least one local-zone specified and view-first is no, the default
local-zones will be added to this view. Defaults can be disabled
using the nodefault type. When view-first is yes or when a view
does not have a local-zone, the global local-zone will be used
including it's default zones.
llooccaall--ddaattaa:: _"_<_r_e_s_o_u_r_c_e _r_e_c_o_r_d _s_t_r_i_n_g_>_"
View specific local-data elements. Has the same behaviour as the
global local-data elements.
llooccaall--ddaattaa--ppttrr:: _"_I_P_a_d_d_r _n_a_m_e_"
View specific local-data-ptr elements. Has the same behaviour as
the global local-data-ptr elements.
vviieeww--ffiirrsstt:: _<_y_e_s _o_r _n_o_>
If enabled, it attempts to use the global local-zone and
local-data if there is no match in the view specific options. The
default is no.
PPyytthhoonn MMoodduullee OOppttiioonnss The ppyytthhoonn:: clause gives the settings for the _p_y_t_h_o_n(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 mmoodduullee--ccoonnffiigg:: option (usually first, or between the validator and iterator). Multiple instances of the python module are supported by adding the word “python” more than once.
If the cchhrroooott:: option is enabled, you should make sure Python's library
directory structure is bind mounted in the new root environment, see
_m_o_u_n_t(8). Also the ppyytthhoonn--ssccrriipptt:: path should be specified as an
absolute path relative to the new root, or as a relative path to the
working directory.
ppyytthhoonn--ssccrriipptt:: _<_p_y_t_h_o_n _f_i_l_e_>
The script file to load. Repeat this option for every python
module instance added to the mmoodduullee--ccoonnffiigg:: option.
DDyynnaammiicc LLiibbrraarryy MMoodduullee OOppttiioonnss The ddyynnlliibb:: clause gives the settings for the _d_y_n_l_i_b module. This module is only a very small wrapper that allows dynamic modules to be loaded on runtime instead of being compiled into the application. To enable the dynlib module it has to be compiled into the daemon, and the word “dynlib” has to be put in the mmoodduullee--ccoonnffiigg:: option. Multiple instances of dynamic libraries are supported by adding the word “dynlib” more than once.
The ddyynnlliibb--ffiillee:: path should be specified as an absolute path relative to
the new path set by cchhrroooott:: option, or as a relative path to the working
directory.
ddyynnlliibb--ffiillee:: _<_d_y_n_l_i_b _f_i_l_e_>
The dynamic library file to load. Repeat this option for every
dynlib module instance added to the mmoodduullee--ccoonnffiigg:: option.
DDNNSS6644 MMoodduullee OOppttiioonnss The dns64 module must be configured in the mmoodduullee--ccoonnffiigg:: “dns64 validator iterator” directive and be compiled into the daemon to be enabled. These settings go in the sseerrvveerr:: section.
ddnnss6644--pprreeffiixx:: _<_I_P_v_6 _p_r_e_f_i_x_>
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.
ddnnss6644--ssyynntthhaallll:: _<_y_e_s _o_r _n_o_>
Debug option, default no. If enabled, synthesize all AAAA records
despite the presence of actual AAAA records.
ddnnss6644--iiggnnoorree--aaaaaaaa:: _<_n_a_m_e_>
List domain for which the AAAA records are ignored and the A
record is used by dns64 processing instead. Can be entered
multiple times, list a new domain for which it applies, one per
line. Applies also to names underneath the name given.
NNAATT6644 OOppeerraattiioonn NAT64 operation allows using a NAT64 prefix for outbound requests to IPv4-only servers. It is controlled by two options in the sseerrvveerr:: section:
ddoo--nnaatt6644:: _<_y_e_s _o_r _n_o_>
Use NAT64 to reach IPv4-only servers. Consider also enabling
pprreeffeerr--iipp66 to prefer native IPv6 connections to nameservers.
Default no.
nnaatt6644--pprreeffiixx:: _<_I_P_v_6 _p_r_e_f_i_x_>
Use a specific NAT64 prefix to reach IPv4-only servers. Defaults
to using the prefix configured in ddnnss6644--pprreeffiixx, which in turn
defaults to 64:ff9b::/96. The prefix length must be one of /32,
/40, /48, /56, /64 or /96.
DDNNSSCCrryypptt OOppttiioonnss The ddnnssccrryypptt:: clause gives the settings of the dnscrypt channel. While those options are available, they are only meaningful if Unbound was compiled with -–-eennaabbllee--ddnnssccrryypptt. Currently certificate and secret/public keys cannot be generated by Unbound. You can use dnscrypt-wrapper to generate those: https://github.com/cofyc/dnscrypt- wrapper/blob/master/README.md#usage
ddnnssccrryypptt--eennaabbllee:: _<_y_e_s _o_r _n_o_>
Whether or not the ddnnssccrryypptt config should be enabled. You may
define configuration but not activate it. The default is no.
ddnnssccrryypptt--ppoorrtt:: _<_p_o_r_t _n_u_m_b_e_r_>
On which port should ddnnssccrryypptt should be activated. Note that you
should have a matching iinntteerrffaaccee option defined in the sseerrvveerr
section for this port.
ddnnssccrryypptt--pprroovviiddeerr:: _<_p_r_o_v_i_d_e_r _n_a_m_e_>
The provider name to use to distribute certificates. This is of
the form: 22..ddnnssccrryypptt--cceerrtt..eexxaammppllee..ccoomm... The name _M_U_S_T end with a
dot.
ddnnssccrryypptt--sseeccrreett--kkeeyy:: _<_p_a_t_h _t_o _s_e_c_r_e_t _k_e_y _f_i_l_e_>
Path to the time limited secret key file. This option may be
specified multiple times.
ddnnssccrryypptt--pprroovviiddeerr--cceerrtt:: _<_p_a_t_h _t_o _c_e_r_t _f_i_l_e_>
Path to the certificate related to the ddnnssccrryypptt--sseeccrreett--kkeeyys. This
option may be specified multiple times.
ddnnssccrryypptt--pprroovviiddeerr--cceerrtt--rroottaatteedd:: _<_p_a_t_h _t_o _c_e_r_t _f_i_l_e_>
Path to a certificate that we should be able to serve existing
connection from but do not want to advertise over
ddnnssccrryypptt--pprroovviiddeerr's TXT record certs distribution. A typical use
case is when rotating certificates, existing clients may still use
the client magic from the old cert in their queries until they
fetch and update the new cert. Likewise, it would allow one to
prime the new cert/key without distributing the new cert yet, this
can be useful when using a network of servers using anycast and on
which the configuration may not get updated at the exact same
time. By priming the cert, the servers can handle both old and new
certs traffic while distributing only one. This option may be
specified multiple times.
ddnnssccrryypptt--sshhaarreedd--sseeccrreett--ccaacchhee--ssiizzee:: _<_m_e_m_o_r_y _s_i_z_e_>
Give the size of the data structure in which the shared secret
keys are kept in. Default 4m. In bytes or use m(mega), k(kilo),
g(giga). The shared secret cache is used when a same client is
making multiple queries using the same public key. It saves a
substantial amount of CPU.
ddnnssccrryypptt--sshhaarreedd--sseeccrreett--ccaacchhee--ssllaabbss:: _<_n_u_m_b_e_r_>
Give power of 2 number of slabs, this is used to reduce lock
contention in the dnscrypt shared secrets cache. Close to the
number of cpus is a fairly good setting.
ddnnssccrryypptt--nnoonnccee--ccaacchhee--ssiizzee:: _<_m_e_m_o_r_y _s_i_z_e_>
Give the size of the data structure in which the client nonces are
kept in. Default 4m. In bytes or use m(mega), k(kilo), g(giga).
The nonce cache is used to prevent dnscrypt message replaying.
Client nonce should be unique for any pair of client pk/server sk.
ddnnssccrryypptt--nnoonnccee--ccaacchhee--ssllaabbss:: _<_n_u_m_b_e_r_>
Give power of 2 number of slabs, this is used to reduce lock
contention in the dnscrypt nonce cache. Close to the number of
cpus is a fairly good setting.
EEDDNNSS CClliieenntt SSuubbnneett MMoodduullee OOppttiioonnss The ECS module must be configured in the mmoodduullee--ccoonnffiigg:: “subnetcache validator iterator” directive and be compiled into the daemon to be enabled. These settings go in the sseerrvveerr:: section.
If the destination address is allowed in the configuration Unbound will
add the EDNS0 option to the query containing the relevant part of the
client's address. When an answer contains the ECS option the response
and the option are placed in a specialized cache. If the authority
indicated no support, the response is stored in the regular cache.
Additionally, when a client includes the option in its queries, Unbound
will forward the option when sending the query to addresses that are
explicitly allowed in the configuration using sseenndd--cclliieenntt--ssuubbnneett. The
option will always be forwarded, regardless the allowed addresses, if
cclliieenntt--ssuubbnneett--aallwwaayyss--ffoorrwwaarrdd is set to yes. In this case the lookup in
the regular cache is skipped.
The maximum size of the ECS cache is controlled by 'msg-cache-size' in
the configuration file. On top of that, for each query only 100 different
subnets are allowed to be stored for each address family. Exceeding that
number, older entries will be purged from cache.
This module does not interact with the sseerrvvee--eexxppiirreedd** and pprreeffeettcchh::
options.
sseenndd--cclliieenntt--ssuubbnneett:: _<_I_P _a_d_d_r_e_s_s_>
Send client source address to this authority. Append /num to
indicate a classless delegation netblock, for example like
10.2.3.4/24 or 2001::11/64. Can be given multiple times.
Authorities not listed will not receive edns-subnet information,
unless domain in query is specified in cclliieenntt--ssuubbnneett--zzoonnee.
cclliieenntt--ssuubbnneett--zzoonnee:: _<_d_o_m_a_i_n_>
Send client source address in queries for this domain and its
subdomains. Can be given multiple times. Zones not listed will not
receive edns-subnet information, unless hosted by authority
specified in sseenndd--cclliieenntt--ssuubbnneett.
cclliieenntt--ssuubbnneett--aallwwaayyss--ffoorrwwaarrdd:: _<_y_e_s _o_r _n_o_>
Specify whether the ECS address check (configured using
sseenndd--cclliieenntt--ssuubbnneett) is applied for all queries, even if the
triggering query contains an ECS record, or only for queries for
which the ECS record is generated using the querier address (and
therefore did not contain ECS data in the client query). If
enabled, the address check is skipped when the client query
contains an ECS record. And the lookup in the regular cache is
skipped. Default is no.
mmaaxx--cclliieenntt--ssuubbnneett--iippvv66:: _<_n_u_m_b_e_r_>
Specifies the maximum prefix length of the client source address
we are willing to expose to third parties for IPv6. Defaults to
56.
mmaaxx--cclliieenntt--ssuubbnneett--iippvv44:: _<_n_u_m_b_e_r_>
Specifies the maximum prefix length of the client source address
we are willing to expose to third parties for IPv4. Defaults to
24.
mmiinn--cclliieenntt--ssuubbnneett--iippvv66:: _<_n_u_m_b_e_r_>
Specifies the minimum prefix length of the IPv6 source mask we are
willing to accept in queries. Shorter source masks result in
REFUSED answers. Source mask of 0 is always accepted. Default is
0.
mmiinn--cclliieenntt--ssuubbnneett--iippvv44:: _<_n_u_m_b_e_r_>
Specifies the minimum prefix length of the IPv4 source mask we are
willing to accept in queries. Shorter source masks result in
REFUSED answers. Source mask of 0 is always accepted. Default is
0.
mmaaxx--eeccss--ttrreeee--ssiizzee--iippvv44:: _<_n_u_m_b_e_r_>
Specifies the maximum number of subnets ECS answers kept in the
ECS radix tree. This number applies for each qname/qclass/qtype
tuple. Defaults to 100.
mmaaxx--eeccss--ttrreeee--ssiizzee--iippvv66:: _<_n_u_m_b_e_r_>
Specifies the maximum number of subnets ECS answers kept in the
ECS radix tree. This number applies for each qname/qclass/qtype
tuple. Defaults to 100.
OOppppoorrttuunniissttiicc IIPPsseecc SSuuppppoorrtt MMoodduullee OOppttiioonnss The IPsec module must be configured in the mmoodduullee--ccoonnffiigg:: “ipsecmod validator iterator” directive and be compiled into Unbound by using -–-eennaabbllee--iippsseeccmmoodd to be enabled. These settings go in the sseerrvveerr:: section.
When Unbound receives an A/AAAA query that is not in the cache and finds
a valid answer, it will withhold returning the answer and instead will
generate an IPSECKEY subquery for the same domain name. If an answer was
found, Unbound will call an external hook passing the following
arguments:
_Q_N_A_M_E #
Domain name of the A/AAAA and IPSECKEY query. In string
format.
_I_P_S_E_C_K_E_Y _T_T_L #
TTL of the IPSECKEY RRset.
_A_/_A_A_A_A #
String of space separated IP addresses present in the A/AAAA
RRset. The IP addresses are in string format.
_I_P_S_E_C_K_E_Y #
String of space separated IPSECKEY RDATA present in the
IPSECKEY RRset. The IPSECKEY RDATA are in DNS presentation
format.
The A/AAAA answer is then cached and returned to the client. If the
external hook was called the TTL changes to ensure it doesn't surpass
iippsseeccmmoodd--mmaaxx--ttttll.
The same procedure is also followed when pprreeffeettcchh:: is used, but the
A/AAAA answer is given to the client before the hook is called.
iippsseeccmmoodd--mmaaxx--ttttll ensures that the A/AAAA answer given from cache is still
relevant for opportunistic IPsec.
iippsseeccmmoodd--eennaabblleedd:: _<_y_e_s _o_r _n_o_>
Specifies whether the IPsec module is enabled or not. The IPsec
module still needs to be defined in the mmoodduullee--ccoonnffiigg:: directive.
This option facilitates turning on/off the module without
restarting/reloading Unbound. Defaults to yes.
iippsseeccmmoodd--hhooookk:: _<_f_i_l_e_n_a_m_e_>
Specifies the external hook that Unbound will call with _s_y_s_t_e_m(3).
The file can be specified as an absolute/relative path. The file
needs the proper permissions to be able to be executed by the same
user that runs Unbound. It must be present when the IPsec module
is defined in the mmoodduullee--ccoonnffiigg:: directive.
iippsseeccmmoodd--ssttrriicctt:: _<_y_e_s _o_r _n_o_>
If enabled Unbound requires the external hook to return a success
value of 0. Failing to do so Unbound will reply with SERVFAIL.
The A/AAAA answer will also not be cached. Defaults to no.
iippsseeccmmoodd--mmaaxx--ttttll:: _<_s_e_c_o_n_d_s_>
Time to live maximum for A/AAAA cached records after calling the
external hook. Defaults to 3600.
iippsseeccmmoodd--iiggnnoorree--bboogguuss:: _<_y_e_s _o_r _n_o_>
Specifies the behaviour of Unbound when the IPSECKEY answer is
bogus. If set to yes, the hook will be called and the A/AAAA
answer will be returned to the client. If set to no, the hook
will not be called and the answer to the A/AAAA query will be
SERVFAIL. Mainly used for testing. Defaults to no.
iippsseeccmmoodd--aallllooww:: _<_d_o_m_a_i_n_>
Allow the ipsecmod functionality for the domain so that the module
logic will be executed. Can be given multiple times, for
different domains. If the option is not specified, all domains
are treated as being allowed (default).
iippsseeccmmoodd--wwhhiitteelliisstt:: _<_y_e_s _o_r _n_o_>
Alternate syntax for iippsseeccmmoodd--aallllooww.
CCaacchhee DDBB MMoodduullee OOppttiioonnss The Cache DB module must be configured in the mmoodduullee--ccoonnffiigg:: “validator cachedb iterator” directive and be compiled into the daemon with -–-eennaabbllee--ccaacchheeddbb. If this module is enabled and configured, the specified backend database works as a second level cache: When Unbound cannot find an answer to a query in its built-in in-memory cache, it consults the specified backend. If it finds a valid answer in the backend, Unbound uses it to respond to the query without performing iterative DNS resolution. If Unbound cannot even find an answer in the backend, it resolves the query as usual, and stores the answer in the backend.
This module interacts with the sseerrvvee--eexxppiirreedd--** options and will reply
with expired data if Unbound is configured for that. Currently the use
of sseerrvvee--eexxppiirreedd--cclliieenntt--ttiimmeeoouutt:: and sseerrvvee--eexxppiirreedd--rreeppllyy--ttttll:: is not
consistent for data originating from the external cache as these will
result in a reply with 0 TTL without trying to update the data first,
ignoring the configured values.
If Unbound was built with ----wwiitthh--lliibbhhiirreeddiiss on a system that has
installed the hiredis C client library of Redis, then the "redis" backend
can be used. This backend communicates with the specified Redis server
over a TCP connection to store and retrieve cache data. It can be used
as a persistent and/or shared cache backend. It should be noted that
Unbound never removes data stored in the Redis server, even if some data
have expired in terms of DNS TTL or the Redis server has cached too much
data; if necessary the Redis server must be configured to limit the cache
size, preferably with some kind of least-recently-used eviction policy.
Additionally, the rreeddiiss--eexxppiirree--rreeccoorrddss option can be used in order to set
the relative DNS TTL of the message as timeout to the Redis records; keep
in mind that some additional memory is used per key and that the expire
information is stored as absolute Unix timestamps in Redis (computer time
must be stable). This backend uses synchronous communication with the
Redis server based on the assumption that the communication is stable and
sufficiently fast. The thread waiting for a response from the Redis
server cannot handle other DNS queries. Although the backend has the
ability to reconnect to the server when the connection is closed
unexpectedly and there is a configurable timeout in case the server is
overly slow or hangs up, these cases are assumed to be very rare. If
connection close or timeout happens too often, Unbound will be
effectively unusable with this backend. It's the administrator's
responsibility to make the assumption hold.
The ccaacchheeddbb:: clause gives custom settings of the cache DB module.
bbaacckkeenndd:: _<_b_a_c_k_e_n_d _n_a_m_e_>
Specify the backend database name. The default database is the
in-memory backend named "testframe", which, as the name suggests,
is not of any practical use. Depending on the build-time
configuration, "redis" backend may also be used as described
above.
sseeccrreett--sseeeedd:: _<_"_s_e_c_r_e_t _s_t_r_i_n_g_"_>
Specify a seed to calculate a hash value from query information.
This value will be used as the key of the corresponding answer for
the backend database and can be customized if the hash should not
be predictable operationally. If the backend database is shared
by multiple Unbound instances, all instances must use the same
secret seed. This option defaults to "default".
The following ccaacchheeddbb options are specific to the redis backend.
rreeddiiss--sseerrvveerr--hhoosstt:: _<_s_e_r_v_e_r _a_d_d_r_e_s_s _o_r _n_a_m_e_>
The IP (either v6 or v4) address or domain name of the Redis
server. In general an IP address should be specified as otherwise
Unbound will have to resolve the name of the server every time it
establishes a connection to the server. This option defaults to
"127.0.0.1".
rreeddiiss--sseerrvveerr--ppoorrtt:: _<_p_o_r_t _n_u_m_b_e_r_>
The TCP port number of the Redis server. This option defaults to
6379.
rreeddiiss--sseerrvveerr--ppaatthh:: _<_u_n_i_x _s_o_c_k_e_t _p_a_t_h_>
The unix socket path to connect to the redis server. Off by
default, and it can be set to "" to turn this off. Unix sockets
may have better throughput than the IP address option.
rreeddiiss--sseerrvveerr--ppaasssswwoorrdd:: _"_<_p_a_s_s_w_o_r_d_>_"
The Redis AUTH password to use for the redis server. Only
relevant if Redis is configured for client password authorisation.
Off by default, and it can be set to "" to turn this off.
rreeddiiss--ttiimmeeoouutt:: _<_m_s_e_c_>
The period until when Unbound waits for a response from the Redis
sever. If this timeout expires Unbound closes the connection,
treats it as if the Redis server does not have the requested data,
and will try to re-establish a new connection later. This option
defaults to 100 milliseconds.
rreeddiiss--eexxppiirree--rreeccoorrddss:: _<_y_e_s _o_r _n_o_>
If Redis record expiration is enabled. If yes, Unbound sets
timeout for Redis records so that Redis can evict keys that have
expired automatically. If Unbound is configured with sseerrvvee--
eexxppiirreedd and sseerrvvee--eexxppiirreedd--ttttll is 0, this option is internally
reverted to "no". Redis SETEX support is required for this option
(Redis >= 2.0.0). This option defaults to no.
DDNNSSTTAAPP LLooggggiinngg OOppttiioonnss DNSTAP support, when compiled in by using -–-eennaabbllee--ddnnssttaapp, is enabled in the ddnnssttaapp:: section. This starts an extra thread (when compiled with threading) that writes the log information to the destination. If Unbound is compiled without threading it does not spawn a thread, but connects per-process to the destination.
ddnnssttaapp--eennaabbllee:: _<_y_e_s _o_r _n_o_>
If dnstap is enabled. Default no. If yes, it connects to the
dnstap server and if any of the dnstap-log-..-messages options is
enabled it sends logs for those messages to the server.
ddnnssttaapp--bbiiddiirreeccttiioonnaall:: _<_y_e_s _o_r _n_o_>
Use frame streams in bidirectional mode to transfer DNSTAP
messages. Default is yes.
ddnnssttaapp--ssoocckkeett--ppaatthh:: _<_f_i_l_e _n_a_m_e_>
Sets the unix socket file name for connecting to the server that
is listening on that socket. Default is "".
ddnnssttaapp--iipp:: _<_I_P_a_d_d_r_e_s_s_[_@_p_o_r_t_]_>
If "", the unix socket is used, if set with an IP address (IPv4 or
IPv6) that address is used to connect to the server.
ddnnssttaapp--ttllss:: _<_y_e_s _o_r _n_o_>
Set this to use TLS to connect to the server specified in ddnnssttaapp--
iipp. The default is yes. If set to no, TCP is used to connect to
the server.
ddnnssttaapp--ttllss--sseerrvveerr--nnaammee:: _<_n_a_m_e _o_f _T_L_S _a_u_t_h_e_n_t_i_c_a_t_i_o_n_>
The TLS server name to authenticate the server with. Used when
ddnnssttaapp--ttllss is enabled. If "" it is ignored, default "".
ddnnssttaapp--ttllss--cceerrtt--bbuunnddllee:: _<_f_i_l_e _n_a_m_e _o_f _c_e_r_t _b_u_n_d_l_e_>
The pem file with certs to verify the TLS server certificate. If
"" the server default cert bundle is used, or the windows cert
bundle on windows. Default is "".
ddnnssttaapp--ttllss--cclliieenntt--kkeeyy--ffiillee:: _<_f_i_l_e _n_a_m_e_>
The client key file for TLS client authentication. If "" client
authentication is not used. Default is "".
ddnnssttaapp--ttllss--cclliieenntt--cceerrtt--ffiillee:: _<_f_i_l_e _n_a_m_e_>
The client cert file for TLS client authentication. Default is
"".
ddnnssttaapp--sseenndd--iiddeennttiittyy:: _<_y_e_s _o_r _n_o_>
If enabled, the server identity is included in the log messages.
Default is no.
ddnnssttaapp--sseenndd--vveerrssiioonn:: _<_y_e_s _o_r _n_o_>
If enabled, the server version if included in the log messages.
Default is no.
ddnnssttaapp--iiddeennttiittyy:: _<_s_t_r_i_n_g_>
The identity to send with messages, if "" the hostname is used.
Default is "".
ddnnssttaapp--vveerrssiioonn:: _<_s_t_r_i_n_g_>
The version to send with messages, if "" the package version is
used. Default is "".
ddnnssttaapp--lloogg--rreessoollvveerr--qquueerryy--mmeessssaaggeess:: _<_y_e_s _o_r _n_o_>
Enable to log resolver query messages. Default is no. These are
messages from Unbound to upstream servers.
ddnnssttaapp--lloogg--rreessoollvveerr--rreessppoonnssee--mmeessssaaggeess:: _<_y_e_s _o_r _n_o_>
Enable to log resolver response messages. Default is no. These
are replies from upstream servers to Unbound.
ddnnssttaapp--lloogg--cclliieenntt--qquueerryy--mmeessssaaggeess:: _<_y_e_s _o_r _n_o_>
Enable to log client query messages. Default is no. These are
client queries to Unbound.
ddnnssttaapp--lloogg--cclliieenntt--rreessppoonnssee--mmeessssaaggeess:: _<_y_e_s _o_r _n_o_>
Enable to log client response messages. Default is no. These are
responses from Unbound to clients.
ddnnssttaapp--lloogg--ffoorrwwaarrddeerr--qquueerryy--mmeessssaaggeess:: _<_y_e_s _o_r _n_o_>
Enable to log forwarder query messages. Default is no.
ddnnssttaapp--lloogg--ffoorrwwaarrddeerr--rreessppoonnssee--mmeessssaaggeess:: _<_y_e_s _o_r _n_o_>
Enable to log forwarder response messages. Default is no.
RReessppoonnssee PPoolliiccyy ZZoonnee OOppttiioonnss Response Policy Zones are configured with rrppzz::, and each one must have a nnaammee::. There can be multiple ones, by listing multiple rpz clauses, each with a different name. RPZ clauses are applied in order of configuration. The rreessppiipp module needs to be added to the mmoodduullee--ccoonnffiigg, e.g.: mmoodduullee-- ccoonnffiigg:: “"rreessppiipp vvaalliiddaattoorr iitteerraattoorr"”.
QNAME, Response IP Address, nsdname, nsip and clientip triggers are
supported. Supported actions are: NXDOMAIN, NODATA, PASSTHRU, DROP,
Local Data, tcp-only and drop. RPZ QNAME triggers are applied after
llooccaall--zzoonneess and before aauutthh--zzoonneess.
The rpz zone is formatted with a SOA start record as usual. The items in
the zone are entries, that specify what to act on (the trigger) and what
to do (the action). The trigger to act on is recorded in the name, the
action to do is recorded as the resource record. The names all end in
the zone name, so you could type the trigger names without a trailing dot
in the zonefile.
An example RPZ record, that answers example.com with NXDOMAIN
example.com CNAME .
The triggers are encoded in the name on the left
name query name
netblock.rpz-client-ip client IP address
netblock.rpz-ip response IP address in the answer
name.rpz-nsdname nameserver name
netblock.rpz-nsip nameserver IP address
The netblock is written as <netblocklen>.<ip address in reverse>. For
IPv6 use 'zz' for '::'. Specify individual addresses with scope length
of 32 or 128. For example, 24.10.100.51.198.rpz-ip is 198.51.100.10/24
and 32.10.zz.db8.2001.rpz-ip is 2001:db8:0:0:0:0:0:10/32.
The actions are specified with the record on the right
CNAME . nxdomain reply
CNAME *. nodata reply
CNAME rpz-passthru. do nothing, allow to continue
CNAME rpz-drop. the query is dropped
CNAME rpz-tcp-only. answer over TCP
A 192.0.2.1 answer with this IP address
Other records like AAAA, TXT and other CNAMEs (not rpz-..) can also be
used to answer queries with that content.
The RPZ zones can be configured in the config file with these settings in
the rrppzz:: block.
nnaammee:: _<_z_o_n_e _n_a_m_e_>
Name of the authority zone.
pprriimmaarryy:: _<_I_P _a_d_d_r_e_s_s _o_r _h_o_s_t _n_a_m_e_>
Where to download a copy of the zone from, with AXFR and IXFR.
Multiple primaries can be specified. They are all tried if one
fails. To use a nondefault port for DNS communication append '@'
with the port number. You can append a '#' and a name, then AXFR
over TLS can be used and the tls authentication certificates will
be checked with that name. If you combine the '@' and '#', the
'@' comes first. If you point it at another Unbound instance, it
would not work because that does not support AXFR/IXFR for the
zone, but if you used uurrll:: to download the zonefile as a text file
from a webserver that would work. If you specify the hostname,
you cannot use the domain from the zonefile, because it may not
have that when retrieving that data, instead use a plain IP
address to avoid a circular dependency on retrieving that IP
address.
mmaasstteerr:: _<_I_P _a_d_d_r_e_s_s _o_r _h_o_s_t _n_a_m_e_>
Alternate syntax for pprriimmaarryy.
uurrll:: _<_u_r_l _t_o _z_o_n_e_f_i_l_e_>
Where to download a zonefile for the zone. With http or https.
An example for the url is
"http://www.example.com/example.org.zone". Multiple url
statements can be given, they are tried in turn. If only urls are
given the SOA refresh timer is used to wait for making new
downloads. If also primaries are listed, the primaries are first
probed with UDP SOA queries to see if the SOA serial number has
changed, reducing the number of downloads. If none of the urls
work, the primaries are tried with IXFR and AXFR. For https, the
ttllss--cceerrtt--bbuunnddllee and the hostname from the url are used to
authenticate the connection.
aallllooww--nnoottiiffyy:: _<_I_P _a_d_d_r_e_s_s _o_r _h_o_s_t _n_a_m_e _o_r _n_e_t_b_l_o_c_k_I_P_/_p_r_e_f_i_x_>
With allow-notify you can specify additional sources of notifies.
When notified, the server attempts to first probe and then zone
transfer. If the notify is from a primary, it first attempts that
primary. Otherwise other primaries are attempted. If there are
no primaries, but only urls, the file is downloaded when notified.
The primaries from primary: and url: statements are allowed notify
by default.
zzoonneeffiillee:: _<_f_i_l_e_n_a_m_e_>
The filename where the zone is stored. If not given then no
zonefile is used. If the file does not exist or is empty, Unbound
will attempt to fetch zone data (eg. from the primary servers).
rrppzz--aaccttiioonn--oovveerrrriiddee:: _<_a_c_t_i_o_n_>
Always use this RPZ action for matching triggers from this zone.
Possible action are: nxdomain, nodata, passthru, drop, disabled
and cname.
rrppzz--ccnnaammee--oovveerrrriiddee:: _<_d_o_m_a_i_n_>
The CNAME target domain to use if the cname action is configured
for rrppzz--aaccttiioonn--oovveerrrriiddee.
rrppzz--lloogg:: _<_y_e_s _o_r _n_o_>
Log all applied RPZ actions for this RPZ zone. Default is no.
rrppzz--lloogg--nnaammee:: _<_n_a_m_e_>
Specify a string to be part of the log line, for easy referencing.
rrppzz--ssiiggnnaall--nnxxddoommaaiinn--rraa:: _<_y_e_s _o_r _n_o_>
Signal when a query is blocked by the RPZ with NXDOMAIN with an
unset RA flag. This allows certain clients, like dnsmasq, to
infer that the domain is externally blocked. Default is no.
ffoorr--ddoowwnnssttrreeaamm:: _<_y_e_s _o_r _n_o_>
If enabled the zone is authoritatively answered for and queries
for the RPZ zone information are answered to downstream clients.
This is useful for monitoring scripts, that can then access the
SOA information to check if the rpz information is up to date.
Default is no.
ttaaggss:: _<_l_i_s_t _o_f _t_a_g_s_>
Limit the policies from this RPZ clause to clients with a matching
tag. Tags need to be defined in ddeeffiinnee--ttaagg and can be assigned to
client addresses using aacccceessss--ccoonnttrrooll--ttaagg. Enclose list of tags in
quotes ("") and put spaces between tags. If no tags are specified
the policies from this clause will be applied for all clients.
MMEEMMOORRYY CCOONNTTRROOLL EEXXAAMMPPLLEE #
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: 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"
FFIILLEESS #
_/_v_a_r_/_u_n_b_o_u_n_d_/_e_t_c
default Unbound working directory.
_/_v_a_r_/_u_n_b_o_u_n_d
default _c_h_r_o_o_t(2) location.
_/_v_a_r_/_u_n_b_o_u_n_d_/_e_t_c_/_u_n_b_o_u_n_d_._c_o_n_f
Unbound configuration file.
_u_n_b_o_u_n_d_._l_o_g
Unbound log file. default is to log to _s_y_s_l_o_g(3).
SSEEEE AALLSSOO #
_u_n_b_o_u_n_d(8), _u_n_b_o_u_n_d_-_c_h_e_c_k_c_o_n_f(8).
AAUUTTHHOORRSS #
UUnnbboouunndd was written by NLnet Labs. Please see CREDITS file in the
distribution for further details.
NLnet Labs August 30, 2023 unbound.conf(5)