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| Copyright 2016 Lennart Poettering |
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| |
| <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>DOMAIN</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> --openpgp</command> |
| <arg choice="plain"><replaceable>USER@DOMAIN</replaceable></arg> |
| </cmdsynopsis> |
| |
| <cmdsynopsis> |
| <command>systemd-resolve</command> |
| <arg choice="opt" rep="repeat">OPTIONS</arg> |
| <command> --tlsa</command> |
| <arg choice="plain"><replaceable>DOMAIN<optional>:PORT</optional></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 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> host name or all data from <filename>/etc/hosts</filename>.</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>--openpgp</option> switch may be used to query PGP keys stored as |
| <ulink url="https://tools.ietf.org/html/rfc7929">OPENPGPKEY</ulink> resource records. |
| When this option is specified one or more e-mail address must be specified.</para> |
| |
| <para>The <option>--tlsa</option> switch maybe be used to query TLS public |
| keys stored as |
| <ulink url="https://tools.ietf.org/html/rfc6698">TLSA</ulink> resource records. |
| When this option is specified one or more domain names must be specified.</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>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></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>--openpgp</option></term> |
| |
| <listitem><para>Enables OPENPGPKEY resource record resolution (see above). Specified e-mail |
| addresses are converted to the corresponding DNS domain name, and any OPENPGPKEY keys are |
| printed.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--tlsa</option></term> |
| |
| <listitem><para>Enables TLSA resource record resolution (see above). |
| 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 an argument after |
| <option>--tlsa</option>, otherwise <constant>tcp</constant> will be |
| used.</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>--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></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> |
| |
| <varlistentry> |
| <term><option>--flush-caches</option></term> |
| |
| <listitem><para>Flushes all DNS resource record caches the service maintains locally.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--status</option></term> |
| |
| <listitem><para>Shows the global and per-link DNS settings in currently in effect.</para></listitem> |
| </varlistentry> |
| |
| <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" /> |
| </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 |
| 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</title> |
| |
| <programlisting>$ systemd-resolve 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 MX record of the <literal>yahoo.com</literal> domain</title> |
| |
| <programlisting>$ systemd-resolve -t MX yahoo.com --legend=no |
| 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 SRV service</title> |
| |
| <programlisting>$ systemd-resolve --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</title> |
| |
| <programlisting>$ systemd-resolve --openpgp zbyszek@fedoraproject.org |
| d08ee310438ca124a6149ea5cc21b6313b390dce485576eff96f8722._openpgpkey.fedoraproject.org. IN OPENPGPKEY |
| mQINBFBHPMsBEACeInGYJCb+7TurKfb6wGyTottCDtiSJB310i37/6ZYoeIay/5soJjlMyf |
| MFQ9T2XNT/0LM6gTa0MpC1st9LnzYTMsT6tzRly1D1UbVI6xw0g0vE5y2Cjk3xUwAynCsSs |
| … |
| </programlisting> |
| </example> |
| |
| <example> |
| <title>Retrieve a TLS key (<literal>=tcp</literal> and |
| <literal>:443</literal> could be skipped)</title> |
| |
| <programlisting>$ systemd-resolve --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> |
| </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> |