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<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="resolvectl" conditional='ENABLE_RESOLVE'
<refpurpose>Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services; introspect and reconfigure the DNS resolver</refpurpose>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="req">COMMAND</arg>
<arg choice="opt" rep="repeat">NAME</arg>
<para><command>resolvectl</command> may be used to resolve domain names, IPv4 and IPv6 addresses, DNS resource
records and services with the
resolver service. By default, the specified list of parameters will be resolved as hostnames, retrieving their IPv4
and IPv6 addresses. If the parameters specified are formatted as IPv4 or IPv6 operation the reverse operation is
done, and a hostname is retrieved for the specified addresses.</para>
<para>The program's output contains information about the protocol used for the look-up and on which network
interface the data was discovered. It also contains information on whether the information could be
authenticated. All data for which local DNSSEC validation succeeds is considered authenticated. Moreover all data
originating from local, trusted sources is also reported authenticated, including resolution of the local host
name, the <literal>localhost</literal> hostname or all data from <filename>/etc/hosts</filename>.</para>
<term><command>query</command> <replaceable>HOSTNAME|ADDRESS</replaceable></term>
<listitem><para>Resolve domain names, as well as IPv4 and IPv6 addresses. When used in conjunction
with <option>--type=</option> or <option>--class=</option> (see below), resolves low-level DNS
resource records.</para>
<para>If a single-label domain name is specified it is searched for according to the configured
search domains — unless <option>--search=no</option> or
<option>--type=</option>/<option>--class=</option> are specified, both of which turn this logic
<para>If an international domain name is specified, it is automatically translated according to IDNA
rules when resolved via classic DNS — but not for look-ups via MulticastDNS or LLMNR. If
<option>--type=</option>/<option>--class=</option> is used IDNA translation is turned off and domain
names are processed as specified.</para></listitem>
[[<replaceable>NAME</replaceable>] <replaceable>TYPE</replaceable>]
<listitem><para>Resolve <ulink url="">DNS-SD</ulink> and <ulink
url="">SRV</ulink> services, depending on the specified list of
parameters. If three parameters are passed the first is assumed to be the DNS-SD service name, the
second the <constant class='dns'>SRV</constant> service type, and the third the domain to search in.
In this case a full DNS-SD style <constant class='dns'>SRV</constant> and <constant
class='dns'>TXT</constant> lookup is executed. If only two parameters are specified, the first is
assumed to be the <constant class='dns'>SRV</constant> service type, and the second the domain to look
in. In this case no <constant class='dns'>TXT</constant> resource record is requested. Finally, if
only one parameter is specified, it is assumed to be a domain name, that is already prefixed with an
<constant class='dns'>SRV</constant> type, and an <constant class='dns'>SRV</constant> lookup is done
(no <constant class='dns'>TXT</constant>).</para></listitem>
<term><command>openpgp</command> <replaceable>EMAIL@DOMAIN</replaceable></term>
<listitem><para>Query PGP keys stored as <constant class='dns'>OPENPGPKEY</constant> resource records,
see <ulink url="">RFC 7929</ulink>. Specified e-mail addresses
are converted to the corresponding DNS domain name, and any <constant class='dns'>OPENPGPKEY</constant>
keys are printed.</para></listitem>
<listitem><para>Query TLS public keys stored as <constant class='dns'>TLSA</constant> resource
records, see <ulink url="">RFC 6698</ulink>. A query will be
performed for each of the specified names prefixed with the port and family
The port number may be specified after a colon (<literal>:</literal>), otherwise
<constant>443</constant> will be used by default. The family may be specified as the first argument,
otherwise <constant>tcp</constant> will be used.</para></listitem>
<term><command>status</command> [<replaceable>LINK</replaceable>…]</term>
<listitem><para>Shows the global and per-link DNS settings currently in effect. If no command is specified,
this is the implied default.</para></listitem>
<listitem><para>Shows general resolver statistics, including information whether DNSSEC is
enabled and available, as well as resolution and validation statistics.</para></listitem>
<listitem><para>Resets the statistics counters shown in <command>statistics</command> to zero.
This operation requires root privileges.</para></listitem>
<listitem><para>Flushes all DNS resource record caches the service maintains locally. This is mostly
equivalent to sending the <constant>SIGUSR2</constant> to the <command>systemd-resolved</command>
<listitem><para>Flushes all feature level information the resolver learnt about specific servers, and ensures
that the server feature probing logic is started from the beginning with the next look-up request. This is
mostly equivalent to sending the <constant>SIGRTMIN+1</constant> to the <command>systemd-resolved</command>
<term><command>dns</command> [<replaceable>LINK</replaceable> [<replaceable>SERVER</replaceable>…]]</term>
<term><command>domain</command> [<replaceable>LINK</replaceable> [<replaceable>DOMAIN</replaceable>…]]</term>
<term><command>default-route</command> [<replaceable>LINK</replaceable> [<replaceable>BOOL</replaceable>…]]</term>
<term><command>llmnr</command> [<replaceable>LINK</replaceable> [<replaceable>MODE</replaceable>]]</term>
<term><command>mdns</command> [<replaceable>LINK</replaceable> [<replaceable>MODE</replaceable>]]</term>
<term><command>dnssec</command> [<replaceable>LINK</replaceable> [<replaceable>MODE</replaceable>]]</term>
<term><command>dnsovertls</command> [<replaceable>LINK</replaceable> [<replaceable>MODE</replaceable>]]</term>
<term><command>nta</command> [<replaceable>LINK</replaceable> [<replaceable>DOMAIN</replaceable>…]]</term>
<para>Get/set per-interface DNS configuration. These commands may be used to configure various DNS
settings for network interfaces. These commands may be used to inform
<command>systemd-resolved</command> or <command>systemd-networkd</command> about per-interface DNS
configuration determined through external means. The <command>dns</command> command expects IPv4 or
IPv6 address specifications of DNS servers to use. Each address can optionally take a port number
separated with <literal>:</literal>, a network interface name or index separated with
<literal>%</literal>, and a Server Name Indication (SNI) separated with <literal>#</literal>. When
IPv6 address is specified with a port number, then the address must be in the square brackets. That
is, the acceptable full formats are <literal></literal> for
IPv4 and <literal>[1111:2222::3333]</literal> for IPv6. The
<command>domain</command> command expects valid DNS domains, possibly prefixed with
<literal>~</literal>, and configures a per-interface search or route-only domain. The
<command>default-route</command> command expects a boolean parameter, and configures whether the
link may be used as default route for DNS lookups, i.e. if it is suitable for lookups on domains no
other link explicitly is configured for. The <command>llmnr</command>, <command>mdns</command>,
<command>dnssec</command> and <command>dnsovertls</command> commands may be used to configure the
per-interface LLMNR, MulticastDNS, DNSSEC and DNSOverTLS settings. Finally, <command>nta</command>
command may be used to configure additional per-interface DNSSEC NTA domains.</para>
<para>Commands <command>dns</command>, <command>domain</command> and <command>nta</command> can take
a single empty string argument to clear their respective value lists.</para>
<para>For details about these settings, their possible values and their effect, see the
corresponding settings in
<term><command>revert <replaceable>LINK</replaceable></command></term>
<listitem><para>Revert the per-interface DNS configuration. If the DNS configuration is reverted all
per-interface DNS setting are reset to their defaults, undoing all effects of <command>dns</command>,
<command>domain</command>, <command>default-route</command>, <command>llmnr</command>,
<command>mdns</command>, <command>dnssec</command>, <command>dnsovertls</command>,
<command>nta</command>. Note that when a network interface disappears all configuration is lost
automatically, an explicit reverting is not necessary in that case.</para></listitem>
<xi:include href="systemctl.xml" xpointer="log-level" />
<listitem><para>By default, when resolving a hostname, both IPv4 and IPv6
addresses are acquired. By specifying <option>-4</option> only IPv4 addresses are requested, by specifying
<option>-6</option> only IPv6 addresses are requested.</para>
<term><option>-i</option> <replaceable>INTERFACE</replaceable></term>
<listitem><para>Specifies the network interface to execute the query on. This may either be specified as numeric
interface index or as network interface string (e.g. <literal>en0</literal>). Note that this option has no
effect if system-wide DNS configuration (as configured in <filename>/etc/resolv.conf</filename> or
<filename>/etc/systemd/resolved.conf</filename>) in place of per-link configuration is used.</para></listitem>
<term><option>-p</option> <replaceable>PROTOCOL</replaceable></term>
<listitem><para>Specifies the network protocol for the query. May be one of <literal>dns</literal>
(i.e. classic unicast DNS), <literal>llmnr</literal> (<ulink
url="">Link-Local Multicast Name Resolution</ulink>),
<literal>llmnr-ipv4</literal>, <literal>llmnr-ipv6</literal> (LLMNR via the indicated underlying IP
protocols), <literal>mdns</literal> (<ulink url="">Multicast DNS</ulink>),
<literal>mdns-ipv4</literal>, <literal>mdns-ipv6</literal> (MDNS via the indicated underlying IP protocols).
By default the lookup is done via all protocols suitable for the lookup. If used, limits the set of
protocols that may be used. Use this option multiple times to enable resolving via multiple protocols at the
same time. The setting <literal>llmnr</literal> is identical to specifying this switch once with
<literal>llmnr-ipv4</literal> and once via <literal>llmnr-ipv6</literal>. Note that this option does not force
the service to resolve the operation with the specified protocol, as that might require a suitable network
interface and configuration.
The special value <literal>help</literal> may be used to list known values.
<term><option>-t</option> <replaceable>TYPE</replaceable></term>
<term><option>-c</option> <replaceable>CLASS</replaceable></term>
<listitem><para>When used in conjunction with the <command>query</command> command, specifies the DNS
resource record type (e.g. <constant class='dns'>A</constant>, <constant class='dns'>AAAA</constant>,
<constant class='dns'>MX</constant>, …) and class (e.g. <constant>IN</constant>,
<constant>ANY</constant>, …) to look up. If these options are used a DNS resource record set matching
the specified class and type is requested. The class defaults to <constant>IN</constant> if only a
type is specified. The special value <literal>help</literal> may be used to list known values.</para>
<para>Without these options <command>resolvectl query</command> provides high-level domain name to
address and address to domain name resolution. With these options it provides low-level DNS resource
record resolution. The search domain logic is automatically turned off when these options are used,
i.e. specified domain names need to be fully qualified domain names. Moreover, IDNA internal domain
name translation is turned off as well, i.e. international domain names should be specified in
<literal>xn--…</literal> notation, unless look-up in MulticastDNS/LLMNR is desired, in which case
UTF-8 characters should be used.</para></listitem>
<listitem><para>Takes a boolean parameter. If true (the default), when doing a service lookup with
<option>--service</option> the hostnames contained in the <constant class='dns'>SRV</constant>
resource records are resolved as well.</para></listitem>
<listitem><para>Takes a boolean parameter. If true (the default), when doing a DNS-SD service lookup
with <option>--service</option> the <constant class='dns'>TXT</constant> service metadata record is
resolved as well.</para></listitem>
<listitem><para>Takes a boolean parameter. If true (the default), DNS <constant
class='dns'>CNAME</constant> or <constant class='dns'>DNAME</constant> redirections are
followed. Otherwise, if a CNAME or DNAME record is encountered while resolving, an error is
<listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
(the default), DNSSEC validation is applied as usual — under the condition that it is enabled for the
network and for <filename>systemd-resolved.service</filename> as a whole. If false, DNSSEC validation
is disabled for the specific query, regardless of whether it is enabled for the network or in the
service. Note that setting this option to true does not force DNSSEC validation on systems/networks
where DNSSEC is turned off. This option is only suitable to turn off such validation where otherwise
enabled, not enable validation where otherwise disabled.</para></listitem>
<listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
(the default), select domains are resolved on the local system, among them
<literal>localhost</literal>, <literal>_gateway</literal> and <literal>_outbound</literal>, or
entries from <filename>/etc/hosts</filename>. If false these domains are not resolved locally, and
either fail (in case of <literal>localhost</literal>, <literal>_gateway</literal> or
<literal>_outbound</literal> and suchlike) or go to the network via regular DNS/mDNS/LLMNR lookups
(in case of <filename>/etc/hosts</filename> entries).</para></listitem>
<listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
(the default), lookups use the local DNS resource record cache. If false, lookups are routed to the
network instead, regardless if already available in the local cache.</para></listitem>
<listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
(the default), lookups are answered from locally registered LLMNR or mDNS resource records, if
defined. If false, locally registered LLMNR/mDNS records are not considered for the lookup
<listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
(the default), lookups for DS and DNSKEY are answered from the local DNSSEC trust anchors if
possible. If false, the local trust store is not considered for the lookup request.</para></listitem>
<listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
(the default), lookups are answered via DNS, LLMNR or mDNS network requests if they cannot be
synthesized locally, or be answered from the local cache, zone or trust anchors (see above). If false,
the request is not answered from the network and will thus fail if none of the indicated sources can
answer them.</para></listitem>
<listitem><para>Takes a boolean parameter. If true (the default), any specified single-label
hostnames will be searched in the domains configured in the search domain list, if it is
non-empty. Otherwise, the search domain logic is disabled. Note that this option has no effect if
<option>--type=</option> is used (see above), in which case the search domain logic is
unconditionally turned off.</para></listitem>
<listitem><para>Dump the answer as binary data. If there is no argument or if the argument is
<literal>payload</literal>, the payload of the packet is exported. If the argument is
<literal>packet</literal>, the whole packet is dumped in wire format, prefixed by
length specified as a little-endian 64-bit number. This format allows multiple packets
to be dumped and unambiguously parsed.</para></listitem>
<listitem><para>Takes a boolean parameter. If true (the default), column headers and meta information about the
query response are shown. Otherwise, this output is suppressed.</para></listitem>
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
<xi:include href="standard-options.xml" xpointer="no-pager" />
<title>Compatibility with
<citerefentry project="debian"><refentrytitle>resolvconf</refentrytitle><manvolnum>8</manvolnum></citerefentry></title>
<para><command>resolvectl</command> is a multi-call binary. When invoked as <literal>resolvconf</literal>
(generally achieved by means of a symbolic link of this name to the <command>resolvectl</command> binary) it
is run in a limited
<citerefentry project="debian"><refentrytitle>resolvconf</refentrytitle><manvolnum>8</manvolnum></citerefentry>
compatibility mode. It accepts mostly the same arguments and pushes all data into
similar to how <option>dns</option> and <option>domain</option> commands operate. Note that
<command>systemd-resolved.service</command> is the only supported backend, which is different from other
implementations of this command.</para>
<para><filename>/etc/resolv.conf</filename> will only be updated with servers added with this command
when <filename>/etc/resolv.conf</filename> is a symlink to
<filename>/run/systemd/resolve/resolv.conf</filename>, and not a static file. See the discussion of
<filename>/etc/resolv.conf</filename> handling in
<para>Not all operations supported by other implementations are supported natively. Specifically:</para>
<listitem><para>Registers per-interface DNS configuration data with
<command>systemd-resolved</command>. Expects a network interface name as only command line argument. Reads
<citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>-compatible
DNS configuration data from its standard input. Relevant fields are <literal>nameserver</literal> and
<literal>domain</literal>/<literal>search</literal>. This command is mostly identical to invoking
<command>resolvectl</command> with a combination of <option>dns</option> and <option>domain</option>
<listitem><para>Unregisters per-interface DNS configuration data with <command>systemd-resolved</command>. This
command is mostly identical to invoking <command>resolvectl revert</command>.</para></listitem>
<listitem><para>When specified <option>-a</option> and <option>-d</option> will not complain about missing
network interfaces and will silently execute no operation in that case.</para></listitem>
<listitem><para>This switch for "exclusive" operation is supported only partially. It is mapped to an
additional configured search domain of <literal>~.</literal> — i.e. ensures that DNS traffic is preferably
routed to the DNS servers on this interface, unless there are other, more specific domains configured on other
<listitem><para>These switches are not supported and are silently ignored.</para></listitem>
<listitem><para>These switches are not supported and the command will fail if used.</para></listitem>
<citerefentry project="debian"><refentrytitle>resolvconf</refentrytitle><manvolnum>8</manvolnum></citerefentry>
for details on those command line options.</para>
<title>Retrieve the addresses of the <literal></literal> domain (<constant class='dns'>A</constant> and <constant class='dns'>AAAA</constant> resource records)</title>
<programlisting>$ resolvectl query 2a01:238:43ed:c300:10c3:bcf3:3266:da74
-- Information acquired via protocol DNS in 611.6ms.
-- Data is authenticated: no
<title>Retrieve the domain of the <literal></literal> IP address
(<constant class='dns'>PTR</constant> resource record)</title>
<programlisting>$ resolvectl query
-- Information acquired via protocol DNS in 1.2997s.
-- Data is authenticated: no
<title>Retrieve the <constant class='dns'>MX</constant> record of the <literal></literal>
<programlisting>$ resolvectl --legend=no -t MX query IN MX 1 IN MX 1 IN MX 1
<title>Resolve an <constant class='dns'>SRV</constant> service</title>
<programlisting>$ resolvectl service _xmpp-server._tcp
_xmpp-server._tcp/ [priority=20, weight=0] [priority=20, weight=0]
<title>Retrieve a PGP key (<constant class='dns'>OPENPGP</constant> resource record)</title>
<programlisting>$ resolvectl openpgp IN OPENPGPKEY
<title>Retrieve a TLS key (<constant class='dns'>TLSA</constant> resource record)</title>
<programlisting>$ resolvectl tlsa tcp IN TLSA 0 0 1 19400be5b7a31fb733917700789d2f0a2471c0c9d506c0e504c06c16d7cb17c0
-- Cert. usage: CA constraint
-- Selector: Full Certificate
-- Matching type: SHA-256
<para><literal>tcp</literal> and <literal>:443</literal> are optional and could be skipped.</para>
<title>See Also</title>