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<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2016 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
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(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
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Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="systemd-resolve"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>systemd-resolve</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-resolve</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-resolve</refname>
<refpurpose>Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain" rep="repeat"><replaceable>HOSTNAME</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain" rep="repeat"><replaceable>ADDRESS</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<command> --type=<replaceable>TYPE</replaceable></command>
<arg choice="plain" rep="repeat"><replaceable>RRDOMAIN</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<command> --service</command>
<arg choice="plain"><arg choice="opt"><arg choice="opt"><replaceable>NAME</replaceable></arg>
<replaceable>TYPE</replaceable></arg> <replaceable>DOMAIN</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<command> --statistics</command>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-resolve</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<command> --reset-statistics</command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>systemd-resolve</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 operation the reverse operation is
done, and a hostname is retrieved for the specified addresses.</para>
<para>The <option>--type=</option> switch may be used to specify a DNS resource record type (A, AAAA, SOA, MX, ...) in
order to request a specific DNS resource record, instead of the address or reverse address lookups.
The special value <literal>help</literal> may be used to list known values.</para>
<para>The <option>--service</option> switch may be used to resolve <ulink
url="https://tools.ietf.org/html/rfc2782">SRV</ulink> and <ulink
url="https://tools.ietf.org/html/rfc6763">DNS-SD</ulink> services (see below). In this mode, between one and three
arguments are required. If three parameters are passed the first is assumed to be the DNS-SD service name, the
second the SRV service type, and the third the domain to search in. In this case a full DNS-SD style SRV and TXT
lookup is executed. If only two parameters are specified, the first is assumed to be the SRV service type, and the
second the domain to look in. In this case no TXT RR is requested. Finally, if only one parameter is specified, it
is assumed to be a domain name, that is already prefixed with an SRV type, and an SRV lookup is done (no
TXT).</para>
<para>The <option>--statistics</option> switch may be used to show resolver statistics, including information about
the number of successful and failed DNSSEC validations.</para>
<para>The <option>--reset-statistics</option> may be used to reset various statistics counters maintained the
resolver, including those shown in the <option>--statistics</option> output. This operation requires root
privileges.</para>
</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>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-i</option> <replaceable>INTERFACE</replaceable></term>
<term><option>--interface=</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/resolve.conf</filename>) in place of per-link configuration is used.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-p</option> <replaceable>PROTOCOL</replaceable></term>
<term><option>--protocol=</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="https://tools.ietf.org/html/rfc4795">Link-Local Multicast Name Resolution</ulink>),
<literal>llmr-ipv4</literal>, <literal>llmnr-ipv6</literal> (LLMNR 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></listitem>
</varlistentry>
<varlistentry>
<term><option>-t</option> <replaceable>TYPE</replaceable></term>
<term><option>--type=</option><replaceable>TYPE</replaceable></term>
<term><option>-c</option> <replaceable>CLASS</replaceable></term>
<term><option>--class=</option><replaceable>CLASS</replaceable></term>
<listitem><para>Specifies the DNS resource record type (e.g. A, AAAA, MX, …) and class (e.g. IN, ANY, …) 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 IN if only a type is specified.
The special value <literal>help</literal> may be used to list known values.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--service</option></term>
<listitem><para>Enables service resolution. This enables DNS-SD and simple SRV service resolution, depending
on the specified list of parameters (see above).</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--service-address=</option><replaceable>BOOL</replaceable></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 SRV resource records are resolved as well.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--service-txt=</option><replaceable>BOOL</replaceable></term>
<listitem><para>Takes a boolean parameter. If true (the default), when doing a DNS-SD service lookup with
<option>--service</option> the TXT service metadata record is resolved as well.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--cname=</option><replaceable>BOOL</replaceable></term>
<listitem><para>Takes a boolean parameter. If true (the default), DNS CNAME or DNAME redirections are
followed. Otherwise, if a CNAME or DNAME record is encountered while resolving, an error is
returned.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--search=</option><replaceable>BOOL</replaceable></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.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--legend=</option><replaceable>BOOL</replaceable></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></listitem>
</varlistentry>
<varlistentry>
<term><option>--statistics</option></term>
<listitem><para>If specified general resolver statistics are shown, including information whether DNSSEC is
enabled and available, as well as resolution and validation statistics.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--reset-statistics</option></term>
<listitem><para>Resets the statistics counters shown in <option>--statistics</option> to zero.</para></listitem>
</varlistentry>
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<example>
<title>Retrieve the addresses of the <literal>www.0pointer.net</literal> domain</title>
<programlisting>$ systemd-resolve www.0pointer.net</programlisting>
</example>
<example>
<title>Retrieve the domain of the <literal>85.214.157.71</literal> IP address</title>
<programlisting>$ systemd-resolve 85.214.157.71</programlisting>
</example>
<example>
<title>Retrieve the MX record of the <literal>0pointer.net</literal> domain</title>
<programlisting>$ systemd-resolve -t MX 0pointer.net</programlisting>
</example>
<example>
<title>Resolve an SRV service</title>
<programlisting>$ systemd-resolve --service _xmpp-server._tcp gmail.com</programlisting>
</example>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
