journald: bring order of MaxLevelXYZ= setting explanations in sync with listed names

[thirdparty/systemd.git] / man / resolvectl.xml

<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->

<refentry id="resolvectl" conditional='ENABLE_RESOLVE'
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>resolvectl</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>resolvectl</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>resolvectl</refname>
    <refname>resolvconf</refname>
    <refpurpose>Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services; introspect and reconfigure the DNS resolver</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>resolvectl</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="req">COMMAND</arg>
      <arg choice="opt" rep="repeat">NAME</arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>resolvectl</command> may be used to resolve domain names, IPv4 and IPv6 addresses, DNS resource
    records and services with the
    <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    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 addresses 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>
  </refsect1>

  <refsect1>
    <title>Commands</title>
    <variablelist>

      <varlistentry>
        <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
        off.</para>

        <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>

        <para>If combined with <option>--json=</option> (only supported in combination with
        <option>--type=</option>) will output the resource record data in a JSON object.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>service</command>
        [[<replaceable>NAME</replaceable>] <replaceable>TYPE</replaceable>]
        <replaceable>DOMAIN</replaceable></term>

        <listitem><para>Resolve <ulink url="https://tools.ietf.org/html/rfc6763">RFC 6763 DNS-SD</ulink> and
        <ulink url="https://tools.ietf.org/html/rfc2782">RFC 2782 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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <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="https://tools.ietf.org/html/rfc7929">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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>tlsa</command>
        [<replaceable>FAMILY</replaceable>]
        <replaceable>DOMAIN</replaceable>[:<replaceable>PORT</replaceable>]…</term>

        <listitem><para>Query TLS public keys stored as <constant class='dns'>TLSA</constant> resource
        records, see <ulink url="https://tools.ietf.org/html/rfc6698">RFC 6698</ulink>. A query will be
        performed for each of the specified names prefixed with the port and family
        (<literal>_<replaceable>port</replaceable>._<replaceable>family</replaceable>.<replaceable>domain</replaceable></literal>).
        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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>statistics</command></term>

        <listitem><para>Shows general resolver statistics, including information whether DNSSEC is
        enabled and available, as well as resolution and validation statistics.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>reset-statistics</command></term>

        <listitem><para>Resets the statistics counters shown in <command>statistics</command> to zero.
        This operation requires root privileges.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>flush-caches</command></term>

        <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>
        service.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>reset-server-features</command></term>

        <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>
        service.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <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>

        <listitem>
          <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>111.222.333.444:9953%ifname#example.com</literal> for
          IPv4 and <literal>[1111:2222::3333]:9953%ifname#example.com</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
          <citerefentry><refentrytitle>systemd.network</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>

          <xi:include href="version-info.xml" xpointer="v239"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>monitor</command></term>

        <listitem><para>Show a continuous stream of local client resolution queries and their
        responses. Whenever a local query is completed the query's DNS resource lookup key and resource
        records are shown. Note that this displays queries issued locally only, and does not immediately
        relate to DNS requests submitted to configured DNS servers or the LLMNR or MulticastDNS zones, as
        lookups may be answered from the local cache, or might result in multiple DNS transactions (for
        example to validate DNSSEC information). If CNAME/CNAME redirection chains are followed, a separate
        query will be displayed for each element of the chain. Use <option>--json=</option> to enable JSON
        output.</para>

        <xi:include href="version-info.xml" xpointer="v252"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>show-cache</command></term>

        <listitem><para>Show current cache content, per scope. Use <option>--json=</option> to enable JSON
        output.</para>

        <xi:include href="version-info.xml" xpointer="v254"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>show-server-state</command></term>

        <listitem><para>Show detailed server state information, per DNS Server. Use <option>--json=</option>
        to enable JSON output.</para>

        <xi:include href="version-info.xml" xpointer="v255"/></listitem>
      </varlistentry>

      <xi:include href="systemctl.xml" xpointer="log-level" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Options</title>
    <variablelist>
      <varlistentry>
        <term><option>-4</option></term>
        <term><option>-6</option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-i</option> <replaceable>INTERFACE</replaceable></term>
        <term><option>--interface=<replaceable>INTERFACE</replaceable></option></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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-p</option> <replaceable>PROTOCOL</replaceable></term>
        <term><option>--protocol=<replaceable>PROTOCOL</replaceable></option></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="https://tools.ietf.org/html/rfc4795">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="https://www.ietf.org/rfc/rfc6762.txt">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.
        </para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-t</option> <replaceable>TYPE</replaceable></term>
        <term><option>--type=<replaceable>TYPE</replaceable></option></term>
        <term><option>-c</option> <replaceable>CLASS</replaceable></term>
        <term><option>--class=<replaceable>CLASS</replaceable></option></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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--service-address=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--service-txt=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--cname=<replaceable>BOOL</replaceable></option></term>

        <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
        returned.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--validate=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v248"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--synthesize=<replaceable>BOOL</replaceable></option></term>

        <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>, <literal>_outbound</literal>,
        <literal>_localdnsstub</literal> and <literal>_localdnsproxy</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>

        <xi:include href="version-info.xml" xpointer="v248"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--cache=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v248"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--zone=<replaceable>BOOL</replaceable></option></term>

        <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
        request.</para>

        <xi:include href="version-info.xml" xpointer="v248"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--trust-anchor=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v248"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--network=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v248"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--search=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--raw</option><optional>=payload|packet</optional></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--legend=<replaceable>BOOL</replaceable></option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--stale-data=<replaceable>BOOL</replaceable></option></term>

        <listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If true
        (the default), lookups are answered with stale data (expired resource records) if
        possible. If false, the stale data is not considered for the lookup request.</para>

        <xi:include href="version-info.xml" xpointer="v254"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--relax-single-label=<replaceable>BOOL</replaceable></option></term>

        <listitem><para>Takes a boolean parameter; used in conjunction with <command>query</command>. If
        true, rules regarding routing of single-label names are relaxed. Defaults to false. By default,
        lookups of single label names are assumed to refer to local hosts to be resolved via local resolution
        such as LLMNR or via search domain qualification and are not routed to upstream servers as is. If
        this option is enabled these rules are disabled and the queries are routed upstream anyway. Also see
        the <varname>ResolveUnicastSingleLabel=</varname> option in
        <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        which provides a system-wide option that controls this behaviour.</para>

        <xi:include href="version-info.xml" xpointer="v256"/></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="json" />
      <xi:include href="standard-options.xml" xpointer="j" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>
  </refsect1>

  <refsect1>
    <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
    <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
    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
    <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
    </para>

    <para>Not all operations supported by other implementations are supported natively. Specifically:</para>

    <variablelist>
      <varlistentry>
        <term><option>-a</option></term>
        <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>
        commands.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-d</option></term>
        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-f</option></term>

        <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>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-x</option></term>

        <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
        interfaces.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-m</option></term>
        <term><option>-p</option></term>

        <listitem><para>These switches are not supported and are silently ignored.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-u</option></term>
        <term><option>-I</option></term>
        <term><option>-i</option></term>
        <term><option>-l</option></term>
        <term><option>-R</option></term>
        <term><option>-r</option></term>
        <term><option>-v</option></term>
        <term><option>-V</option></term>
        <term><option>--enable-updates</option></term>
        <term><option>--disable-updates</option></term>
        <term><option>--are-updates-enabled</option></term>

        <listitem><para>These switches are not supported and the command will fail if used.</para>

        <xi:include href="version-info.xml" xpointer="v239"/></listitem>
      </varlistentry>

    </variablelist>

    <para>See
    <citerefentry project="debian"><refentrytitle>resolvconf</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    for details on those command line options.</para>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <example>
      <title>Retrieve the addresses of the <literal>www.0pointer.net</literal> domain (<constant class='dns'>A</constant> and <constant class='dns'>AAAA</constant> resource records)</title>

      <programlisting>$ resolvectl query www.0pointer.net
www.0pointer.net: 2a01:238:43ed:c300:10c3:bcf3:3266:da74
                  85.214.157.71

-- Information acquired via protocol DNS in 611.6ms.
-- Data is authenticated: no
</programlisting>
    </example>

    <example>
      <title>Retrieve the domain of the <literal>85.214.157.71</literal> IP address
      (<constant class='dns'>PTR</constant> resource record)</title>

      <programlisting>$ resolvectl query 85.214.157.71
85.214.157.71: gardel.0pointer.net

-- Information acquired via protocol DNS in 1.2997s.
-- Data is authenticated: no
</programlisting>
    </example>

    <example>
      <title>Retrieve the <constant class='dns'>MX</constant> record of the <literal>yahoo.com</literal>
      domain</title>

      <programlisting>$ resolvectl --legend=no -t MX query yahoo.com
yahoo.com. IN MX    1 mta7.am0.yahoodns.net
yahoo.com. IN MX    1 mta6.am0.yahoodns.net
yahoo.com. IN MX    1 mta5.am0.yahoodns.net
</programlisting>
    </example>

    <example>
      <title>Resolve an <constant class='dns'>SRV</constant> service</title>

      <programlisting>$ resolvectl service _xmpp-server._tcp gmail.com
_xmpp-server._tcp/gmail.com: alt1.xmpp-server.l.google.com:5269 [priority=20, weight=0]
                             173.194.210.125
                             alt4.xmpp-server.l.google.com:5269 [priority=20, weight=0]
                             173.194.65.125
                             …
</programlisting>
    </example>

    <example>
      <title>Retrieve a PGP key (<constant class='dns'>OPENPGP</constant> resource record)</title>

      <programlisting>$ resolvectl openpgp zbyszek@fedoraproject.org
d08ee310438ca124a6149ea5cc21b6313b390dce485576eff96f8722._openpgpkey.fedoraproject.org. IN OPENPGPKEY
        mQINBFBHPMsBEACeInGYJCb+7TurKfb6wGyTottCDtiSJB310i37/6ZYoeIay/5soJjlMyf
        MFQ9T2XNT/0LM6gTa0MpC1st9LnzYTMsT6tzRly1D1UbVI6xw0g0vE5y2Cjk3xUwAynCsSs
        …
</programlisting>
    </example>

    <example>
      <title>Retrieve a TLS key (<constant class='dns'>TLSA</constant> resource record)</title>

      <programlisting>$ resolvectl tlsa tcp fedoraproject.org:443
_443._tcp.fedoraproject.org IN TLSA 0 0 1 19400be5b7a31fb733917700789d2f0a2471c0c9d506c0e504c06c16d7cb17c0
        -- Cert. usage: CA constraint
        -- Selector: Full Certificate
        -- Matching type: SHA-256
</programlisting>

      <para><literal>tcp</literal> and <literal>:443</literal> are optional and could be skipped.</para>
    </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para><simplelist type="inline">
      <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd.dnssd</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>resolvconf</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
    </simplelist></para>
  </refsect1>
</refentry>