2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
6 <refentry id=
"resolvectl" conditional='ENABLE_RESOLVE'
7 xmlns:
xi=
"http://www.w3.org/2001/XInclude">
10 <title>resolvectl
</title>
11 <productname>systemd
</productname>
15 <refentrytitle>resolvectl
</refentrytitle>
16 <manvolnum>1</manvolnum>
20 <refname>resolvectl
</refname>
21 <refname>resolvconf
</refname>
22 <refpurpose>Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services; introspect and reconfigure the DNS resolver
</refpurpose>
27 <command>resolvectl
</command>
28 <arg choice=
"opt" rep=
"repeat">OPTIONS
</arg>
29 <arg choice=
"req">COMMAND
</arg>
30 <arg choice=
"opt" rep=
"repeat">NAME
</arg>
35 <title>Description
</title>
37 <para><command>resolvectl
</command> may be used to resolve domain names, IPv4 and IPv6 addresses, DNS resource
38 records and services with the
39 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
40 resolver service. By default, the specified list of parameters will be resolved as hostnames, retrieving their IPv4
41 and IPv6 addresses. If the parameters specified are formatted as IPv4 or IPv6 operation the reverse operation is
42 done, and a hostname is retrieved for the specified addresses.
</para>
44 <para>The program's output contains information about the protocol used for the look-up and on which network
45 interface the data was discovered. It also contains information on whether the information could be
46 authenticated. All data for which local DNSSEC validation succeeds is considered authenticated. Moreover all data
47 originating from local, trusted sources is also reported authenticated, including resolution of the local host
48 name, the
<literal>localhost
</literal> host name or all data from
<filename>/etc/hosts
</filename>.
</para>
52 <title>Options
</title>
55 <term><option>-
4</option></term>
56 <term><option>-
6</option></term>
58 <listitem><para>By default, when resolving a hostname, both IPv4 and IPv6
59 addresses are acquired. By specifying
<option>-
4</option> only IPv4 addresses are requested, by specifying
60 <option>-
6</option> only IPv6 addresses are requested.
</para>
65 <term><option>-i
</option> <replaceable>INTERFACE
</replaceable></term>
66 <term><option>--interface=
</option><replaceable>INTERFACE
</replaceable></term>
68 <listitem><para>Specifies the network interface to execute the query on. This may either be specified as numeric
69 interface index or as network interface string (e.g.
<literal>en0
</literal>). Note that this option has no
70 effect if system-wide DNS configuration (as configured in
<filename>/etc/resolv.conf
</filename> or
71 <filename>/etc/systemd/resolve.conf
</filename>) in place of per-link configuration is used.
</para></listitem>
75 <term><option>-p
</option> <replaceable>PROTOCOL
</replaceable></term>
76 <term><option>--protocol=
</option><replaceable>PROTOCOL
</replaceable></term>
78 <listitem><para>Specifies the network protocol for the query. May be one of
<literal>dns
</literal>
79 (i.e. classic unicast DNS),
<literal>llmnr
</literal> (
<ulink
80 url=
"https://tools.ietf.org/html/rfc4795">Link-Local Multicast Name Resolution
</ulink>),
81 <literal>llmnr-ipv4
</literal>,
<literal>llmnr-ipv6
</literal> (LLMNR via the indicated underlying IP
82 protocols),
<literal>mdns
</literal> (
<ulink url=
"https://www.ietf.org/rfc/rfc6762.txt">Multicast DNS
</ulink>),
83 <literal>mdns-ipv4
</literal>,
<literal>mdns-ipv6
</literal> (MDNS via the indicated underlying IP protocols).
84 By default the lookup is done via all protocols suitable for the lookup. If used, limits the set of
85 protocols that may be used. Use this option multiple times to enable resolving via multiple protocols at the
86 same time. The setting
<literal>llmnr
</literal> is identical to specifying this switch once with
87 <literal>llmnr-ipv4
</literal> and once via
<literal>llmnr-ipv6
</literal>. Note that this option does not force
88 the service to resolve the operation with the specified protocol, as that might require a suitable network
89 interface and configuration.
90 The special value
<literal>help
</literal> may be used to list known values.
95 <term><option>-t
</option> <replaceable>TYPE
</replaceable></term>
96 <term><option>--type=
</option><replaceable>TYPE
</replaceable></term>
97 <term><option>-c
</option> <replaceable>CLASS
</replaceable></term>
98 <term><option>--class=
</option><replaceable>CLASS
</replaceable></term>
100 <listitem><para>Specifies the DNS resource record type (e.g. A, AAAA, MX, …) and class (e.g. IN, ANY, …) to
101 look up. If these options are used a DNS resource record set matching the specified class and type is
102 requested. The class defaults to IN if only a type is specified.
103 The special value
<literal>help
</literal> may be used to list known values.
108 <term><option>--service-address=
</option><replaceable>BOOL
</replaceable></term>
110 <listitem><para>Takes a boolean parameter. If true (the default), when doing a service lookup with
111 <option>--service
</option> the hostnames contained in the SRV resource records are resolved as well.
</para></listitem>
115 <term><option>--service-txt=
</option><replaceable>BOOL
</replaceable></term>
117 <listitem><para>Takes a boolean parameter. If true (the default), when doing a DNS-SD service lookup with
118 <option>--service
</option> the TXT service metadata record is resolved as well.
</para></listitem>
122 <term><option>--cname=
</option><replaceable>BOOL
</replaceable></term>
124 <listitem><para>Takes a boolean parameter. If true (the default), DNS CNAME or DNAME redirections are
125 followed. Otherwise, if a CNAME or DNAME record is encountered while resolving, an error is
126 returned.
</para></listitem>
130 <term><option>--search=
</option><replaceable>BOOL
</replaceable></term>
132 <listitem><para>Takes a boolean parameter. If true (the default), any specified single-label hostnames will be
133 searched in the domains configured in the search domain list, if it is non-empty. Otherwise, the search domain
134 logic is disabled.
</para></listitem>
138 <term><option>--raw
</option><optional>=payload|packet
</optional></term>
140 <listitem><para>Dump the answer as binary data. If there is no argument or if the argument is
141 <literal>payload
</literal>, the payload of the packet is exported. If the argument is
142 <literal>packet
</literal>, the whole packet is dumped in wire format, prefixed by
143 length specified as a little-endian
64-bit number. This format allows multiple packets
144 to be dumped and unambiguously parsed.
</para></listitem>
148 <term><option>--legend=
</option><replaceable>BOOL
</replaceable></term>
150 <listitem><para>Takes a boolean parameter. If true (the default), column headers and meta information about the
151 query response are shown. Otherwise, this output is suppressed.
</para></listitem>
154 <xi:include href=
"standard-options.xml" xpointer=
"help" />
155 <xi:include href=
"standard-options.xml" xpointer=
"version" />
156 <xi:include href=
"standard-options.xml" xpointer=
"no-pager" />
161 <title>Commands
</title>
165 <term><option>query
<replaceable>HOSTNAME|ADDRESS
</replaceable>…
</option></term>
167 <listitem><para>Resolve domain names, IPv4 and IPv6 addresses.
</para></listitem>
171 <term><option>service [[
<replaceable>NAME
</replaceable>]
<replaceable>TYPE
</replaceable>]
<replaceable>DOMAIN
</replaceable></option></term>
173 <listitem><para>Resolve
<ulink url=
"https://tools.ietf.org/html/rfc6763">DNS-SD
</ulink> and
174 <ulink url=
"https://tools.ietf.org/html/rfc2782">SRV
</ulink> services, depending on the specified list of parameters.
175 If three parameters are passed the first is assumed to be the DNS-SD service name, the second the SRV service type,
176 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
177 parameters are specified, the first is assumed to be the SRV service type, and the second the domain to look in. In
178 this case no TXT RR is requested. Finally, if only one parameter is specified, it is assumed to be a domain name,
179 that is already prefixed with an SRV type, and an SRV lookup is done (no TXT).
</para></listitem>
183 <term><option>openpgp
<replaceable>EMAIL@DOMAIN
</replaceable>…
</option></term>
185 <listitem><para>Query PGP keys stored as
<ulink url=
"https://tools.ietf.org/html/rfc7929">OPENPGPKEY
</ulink>
186 resource records. Specified e-mail addresses are converted to the corresponding DNS domain name, and any
187 OPENPGPKEY keys are printed.
</para></listitem>
191 <term><option>tlsa [
<replaceable>FAMILY
</replaceable>]
<replaceable>DOMAIN
</replaceable>[:
<replaceable>PORT
</replaceable>]…
</option></term>
193 <listitem><para>Query TLS public keys stored as
<ulink url=
"https://tools.ietf.org/html/rfc6698">TLSA
</ulink>
194 resource records. A query will be performed for each of the specified names prefixed with the port and family
195 (
<literal>_
<replaceable>port
</replaceable>._
<replaceable>family
</replaceable>.
<replaceable>domain
</replaceable></literal>).
196 The port number may be specified after a colon (
<literal>:
</literal>), otherwise
<constant>443</constant> will be used
197 by default. The family may be specified as the first argument, otherwise
<constant>tcp
</constant> will be used.
</para></listitem>
201 <term><option>status [
<replaceable>LINK
</replaceable>…]
</option></term>
203 <listitem><para>Shows the global and per-link DNS settings in currently in effect. If no command is specified,
204 this is the implied default.
</para></listitem>
208 <term><option>statistics
</option></term>
210 <listitem><para>Shows general resolver statistics, including information whether DNSSEC is
211 enabled and available, as well as resolution and validation statistics.
</para></listitem>
215 <term><option>reset-statistics
</option></term>
217 <listitem><para>Resets the statistics counters shown in
<option>statistics
</option> to zero.
218 This operation requires root privileges.
</para></listitem>
222 <term><option>flush-caches
</option></term>
224 <listitem><para>Flushes all DNS resource record caches the service maintains locally. This is mostly equivalent
225 to sending the
<constant>SIGUSR2
</constant> to the
<command>systemd-resolved
</command>
226 service.
</para></listitem>
230 <term><option>reset-server-features
</option></term>
232 <listitem><para>Flushes all feature level information the resolver learnt about specific servers, and ensures
233 that the server feature probing logic is started from the beginning with the next look-up request. This is
234 mostly equivalent to sending the
<constant>SIGRTMIN+
1</constant> to the
<command>systemd-resolved
</command>
235 service.
</para></listitem>
239 <term><option>dns [
<replaceable>LINK
</replaceable> [
<replaceable>SERVER
</replaceable>…]]
</option></term>
240 <term><option>domain [
<replaceable>LINK
</replaceable> [
<replaceable>DOMAIN
</replaceable>…]]
</option></term>
241 <term><option>default-route [
<replaceable>LINK
</replaceable> [
<replaceable>BOOL
</replaceable>…]]
</option></term>
242 <term><option>llmnr [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</option></term>
243 <term><option>mdns [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</option></term>
244 <term><option>dnssec [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</option></term>
245 <term><option>dnsovertls [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</option></term>
246 <term><option>nta [
<replaceable>LINK
</replaceable> [
<replaceable>DOMAIN
</replaceable>…]]
</option></term>
249 <para>Get/set per-interface DNS configuration. These commands may be used to configure various DNS settings
250 for network interfaces that aren't managed by
251 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>. (These
252 commands will fail when used on interfaces that are managed by
<command>systemd-networkd
</command>, please
253 configure their DNS settings directly inside the
<filename>.network
</filename> files instead.) These commands
254 may be used to inform
<command>systemd-resolved
</command> about per-interface DNS configuration determined
255 through external means. The
<option>dns
</option> command expects IPv4 or IPv6 address specifications of DNS
256 servers to use. The
<option>domain
</option> command expects valid DNS domains, possibly prefixed with
257 <literal>~
</literal>, and configures a per-interface search or route-only domain. The
258 <option>default-route
</option> command expects a boolean paremeter, and configures whether the link may be
259 used as default route for DNS lookups, i.e. if it is suitable for lookups on domains no other link explicitly
260 is configured for. The
<option>llmnr
</option>,
<option>mdns
</option>,
<option>dnssec
</option> and
261 <option>dnsovertls
</option> commands may be used to configure the per-interface LLMNR, MulticastDNS, DNSSEC
262 and DNSOverTLS settings. Finally,
<option>nta
</option> command may be used to configure additional
263 per-interface DNSSEC NTA domains.
</para>
265 <para>Options
<option>dns
</option>,
<option>domain
</option> and
<option>nta
</option> can take
266 a single empty string argument to clear their respective value lists.
</para>
268 <para>For details about these settings, their possible values and their effect, see the corresponding options in
269 <citerefentry><refentrytitle>systemd.network
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
274 <term><option>revert
<replaceable>LINK
</replaceable></option></term>
276 <listitem><para>Revert the per-interface DNS configuration. If the DNS configuration is reverted all
277 per-interface DNS setting are reset to their defaults, undoing all effects of
<option>dns
</option>,
278 <option>domain
</option>,
<option>default-route
</option>,
<option>llmnr
</option>,
<option>mdns
</option>,
279 <option>dnssec
</option>,
<option>dnsovertls
</option>,
<option>nta
</option>. Note that when a network interface
280 disappears all configuration is lost automatically, an explicit reverting is not necessary in that
281 case.
</para></listitem>
288 <title>Compatibility with
<citerefentry><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry></title>
290 <para><command>resolvectl
</command> is a multi-call binary. When invoked as
<literal>resolvconf
</literal>
291 (generally achieved by means of a symbolic link of this name to the
<command>resolvectl
</command> binary) it
292 is run in a limited
<citerefentry><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
293 compatibility mode. It accepts mostly the same arguments and pushes all data into
294 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
295 similar to how
<option>dns
</option> and
<option>domain
</option> commands operate. Note that
296 <command>systemd-resolved.service
</command> is the only supported backend, which is different from other
297 implementations of this command. Note that not all operations supported by other implementations are supported
298 natively. Specifically:
</para>
302 <term><option>-a
</option></term>
303 <listitem><para>Registers per-interface DNS configuration data with
304 <command>systemd-resolved
</command>. Expects a network interface name as only command line argument. Reads
305 <citerefentry><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry> compatible DNS
306 configuration data from its standard input. Relevant fields are
<literal>nameserver
</literal> and
307 <literal>domain
</literal>/
<literal>search
</literal>. This command is mostly identical to invoking
308 <command>resolvectl
</command> with a combination of
<option>dns
</option> and
309 <option>domain
</option> commands.
</para></listitem>
313 <term><option>-d
</option></term>
314 <listitem><para>Unregisters per-interface DNS configuration data with
<command>systemd-resolved
</command>. This
315 command is mostly identical to invoking
<command>resolvectl revert
</command>.
</para></listitem>
319 <term><option>-f
</option></term>
321 <listitem><para>When specified
<option>-a
</option> and
<option>-d
</option> will not complain about missing
322 network interfaces and will silently execute no operation in that case.
</para></listitem>
326 <term><option>-x
</option></term>
328 <listitem><para>This switch for
"exclusive" operation is supported only partially. It is mapped to an
329 additional configured search domain of
<literal>~.
</literal> — i.e. ensures that DNS traffic is preferably
330 routed to the DNS servers on this interface, unless there are other, more specific domains configured on other
331 interfaces.
</para></listitem>
335 <term><option>-m
</option></term>
336 <term><option>-p
</option></term>
338 <listitem><para>These switches are not supported and are silently ignored.
</para></listitem>
342 <term><option>-u
</option></term>
343 <term><option>-I
</option></term>
344 <term><option>-i
</option></term>
345 <term><option>-l
</option></term>
346 <term><option>-R
</option></term>
347 <term><option>-r
</option></term>
348 <term><option>-v
</option></term>
349 <term><option>-V
</option></term>
350 <term><option>--enable-updates
</option></term>
351 <term><option>--disable-updates
</option></term>
352 <term><option>--are-updates-enabled
</option></term>
354 <listitem><para>These switches are not supported and the command will fail if used.
</para></listitem>
359 <para>See
<citerefentry><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry> for details on this command line options.
</para>
363 <title>Examples
</title>
366 <title>Retrieve the addresses of the
<literal>www
.0pointer.net
</literal> domain
</title>
368 <programlisting>$ resolvectl query www
.0pointer.net
369 www
.0pointer.net:
2a01:
238:
43ed:c300:
10c3:bcf3:
3266:da74
372 -- Information acquired via protocol DNS in
611.6ms.
373 -- Data is authenticated: no
378 <title>Retrieve the domain of the
<literal>85.214.157.71</literal> IP address
</title>
380 <programlisting>$ resolvectl query
85.214.157.71
381 85.214.157.71: gardel
.0pointer.net
383 -- Information acquired via protocol DNS in
1.2997s.
384 -- Data is authenticated: no
389 <title>Retrieve the MX record of the
<literal>yahoo.com
</literal> domain
</title>
391 <programlisting>$ resolvectl --legend=no -t MX query yahoo.com
392 yahoo.com. IN MX
1 mta7.am0.yahoodns.net
393 yahoo.com. IN MX
1 mta6.am0.yahoodns.net
394 yahoo.com. IN MX
1 mta5.am0.yahoodns.net
399 <title>Resolve an SRV service
</title>
401 <programlisting>$ resolvectl service _xmpp-server._tcp gmail.com
402 _xmpp-server._tcp/gmail.com: alt1.xmpp-server.l.google.com:
5269 [priority=
20, weight=
0]
404 alt4.xmpp-server.l.google.com:
5269 [priority=
20, weight=
0]
411 <title>Retrieve a PGP key
</title>
413 <programlisting>$ resolvectl openpgp zbyszek@fedoraproject.org
414 d08ee310438ca124a6149ea5cc21b6313b390dce485576eff96f8722._openpgpkey.fedoraproject.org. IN OPENPGPKEY
415 mQINBFBHPMsBEACeInGYJCb+
7TurKfb6wGyTottCDtiSJB310i37/
6ZYoeIay/
5soJjlMyf
416 MFQ9T2XNT/
0LM
6gTa
0MpC
1st
9LnzYTMsT
6tzRly
1D
1UbVI
6xw
0g
0vE
5y
2Cjk
3xUwAynCsSs
422 <title>Retrieve a TLS key (
<literal>tcp
</literal> and
423 <literal>:
443</literal> could be skipped)
</title>
425 <programlisting>$ resolvectl tlsa tcp fedoraproject.org:
443
426 _443._tcp.fedoraproject.org IN TLSA
0 0 1 19400be5b7a31fb733917700789d2f0a2471c0c9d506c0e504c06c16d7cb17c0
427 -- Cert. usage: CA constraint
428 -- Selector: Full Certificate
429 -- Matching type: SHA-
256
435 <title>See Also
</title>
437 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
438 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
439 <citerefentry><refentrytitle>systemd.dnssd
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
440 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
441 <citerefentry><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>