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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<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 succesful 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, dependending

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>