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> hostname or all data from
<filename>/etc/hosts
</filename>.
</para>
52 <title>Commands
</title>
56 <term><command>query
</command> <replaceable>HOSTNAME|ADDRESS
</replaceable>…
</term>
58 <listitem><para>Resolve domain names, IPv4 and IPv6 addresses.
</para></listitem>
62 <term><command>service
</command>
63 [[
<replaceable>NAME
</replaceable>]
<replaceable>TYPE
</replaceable>]
64 <replaceable>DOMAIN
</replaceable></term>
66 <listitem><para>Resolve
<ulink url=
"https://tools.ietf.org/html/rfc6763">DNS-SD
</ulink> and
67 <ulink url=
"https://tools.ietf.org/html/rfc2782">SRV
</ulink> services, depending on the specified list of parameters.
68 If three parameters are passed the first is assumed to be the DNS-SD service name, the second the SRV service type,
69 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
70 parameters are specified, the first is assumed to be the SRV service type, and the second the domain to look in. In
71 this case no TXT RR is requested. Finally, if only one parameter is specified, it is assumed to be a domain name,
72 that is already prefixed with an SRV type, and an SRV lookup is done (no TXT).
</para></listitem>
76 <term><command>openpgp
</command> <replaceable>EMAIL@DOMAIN
</replaceable>…
</term>
78 <listitem><para>Query PGP keys stored as
<ulink url=
"https://tools.ietf.org/html/rfc7929">OPENPGPKEY
</ulink>
79 resource records. Specified e-mail addresses are converted to the corresponding DNS domain name, and any
80 OPENPGPKEY keys are printed.
</para></listitem>
84 <term><command>tlsa
</command>
85 [
<replaceable>FAMILY
</replaceable>]
86 <replaceable>DOMAIN
</replaceable>[:
<replaceable>PORT
</replaceable>]…
</term>
88 <listitem><para>Query TLS public keys stored as
<ulink url=
"https://tools.ietf.org/html/rfc6698">TLSA
</ulink>
89 resource records. A query will be performed for each of the specified names prefixed with the port and family
90 (
<literal>_
<replaceable>port
</replaceable>._
<replaceable>family
</replaceable>.
<replaceable>domain
</replaceable></literal>).
91 The port number may be specified after a colon (
<literal>:
</literal>), otherwise
<constant>443</constant> will be used
92 by default. The family may be specified as the first argument, otherwise
<constant>tcp
</constant> will be used.
</para></listitem>
96 <term><command>status
</command> [
<replaceable>LINK
</replaceable>…]
</term>
98 <listitem><para>Shows the global and per-link DNS settings currently in effect. If no command is specified,
99 this is the implied default.
</para></listitem>
103 <term><command>statistics
</command></term>
105 <listitem><para>Shows general resolver statistics, including information whether DNSSEC is
106 enabled and available, as well as resolution and validation statistics.
</para></listitem>
110 <term><command>reset-statistics
</command></term>
112 <listitem><para>Resets the statistics counters shown in
<command>statistics
</command> to zero.
113 This operation requires root privileges.
</para></listitem>
117 <term><command>flush-caches
</command></term>
119 <listitem><para>Flushes all DNS resource record caches the service maintains locally. This is mostly equivalent
120 to sending the
<constant>SIGUSR2
</constant> to the
<command>systemd-resolved
</command>
121 service.
</para></listitem>
125 <term><command>reset-server-features
</command></term>
127 <listitem><para>Flushes all feature level information the resolver learnt about specific servers, and ensures
128 that the server feature probing logic is started from the beginning with the next look-up request. This is
129 mostly equivalent to sending the
<constant>SIGRTMIN+
1</constant> to the
<command>systemd-resolved
</command>
130 service.
</para></listitem>
134 <term><command>dns
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>SERVER
</replaceable>…]]
</term>
135 <term><command>domain
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>DOMAIN
</replaceable>…]]
</term>
136 <term><command>default-route
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>BOOL
</replaceable>…]]
</term>
137 <term><command>llmnr
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</term>
138 <term><command>mdns
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</term>
139 <term><command>dnssec
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</term>
140 <term><command>dnsovertls
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>MODE
</replaceable>]]
</term>
141 <term><command>nta
</command> [
<replaceable>LINK
</replaceable> [
<replaceable>DOMAIN
</replaceable>…]]
</term>
144 <para>Get/set per-interface DNS configuration. These commands may be used to configure various DNS
145 settings for network interfaces. These commands may be used to inform
146 <command>systemd-resolved
</command> or
<command>systemd-networkd
</command> about per-interface DNS
147 configuration determined through external means. The
<command>dns
</command> command expects IPv4 or
148 IPv6 address specifications of DNS servers to use. The
<command>domain
</command> command expects
149 valid DNS domains, possibly prefixed with
<literal>~
</literal>, and configures a per-interface
150 search or route-only domain. The
<command>default-route
</command> command expects a boolean
151 parameter, and configures whether the link may be used as default route for DNS lookups, i.e. if it
152 is suitable for lookups on domains no other link explicitly is configured for. The
153 <command>llmnr
</command>,
<command>mdns
</command>,
<command>dnssec
</command> and
154 <command>dnsovertls
</command> commands may be used to configure the per-interface LLMNR,
155 MulticastDNS, DNSSEC and DNSOverTLS settings. Finally,
<command>nta
</command> command may be used
156 to configure additional per-interface DNSSEC NTA domains.
</para>
158 <para>Commands
<command>dns
</command>,
<command>domain
</command> and
<command>nta
</command> can take
159 a single empty string argument to clear their respective value lists.
</para>
161 <para>For details about these settings, their possible values and their effect, see the
162 corresponding settings in
163 <citerefentry><refentrytitle>systemd.network
</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
168 <term><command>revert
<replaceable>LINK
</replaceable></command></term>
170 <listitem><para>Revert the per-interface DNS configuration. If the DNS configuration is reverted all
171 per-interface DNS setting are reset to their defaults, undoing all effects of
<command>dns
</command>,
172 <command>domain
</command>,
<command>default-route
</command>,
<command>llmnr
</command>,
173 <command>mdns
</command>,
<command>dnssec
</command>,
<command>dnsovertls
</command>,
174 <command>nta
</command>. Note that when a network interface disappears all configuration is lost
175 automatically, an explicit reverting is not necessary in that case.
</para></listitem>
178 <xi:include href=
"systemctl.xml" xpointer=
"log-level" />
183 <title>Options
</title>
186 <term><option>-
4</option></term>
187 <term><option>-
6</option></term>
189 <listitem><para>By default, when resolving a hostname, both IPv4 and IPv6
190 addresses are acquired. By specifying
<option>-
4</option> only IPv4 addresses are requested, by specifying
191 <option>-
6</option> only IPv6 addresses are requested.
</para>
196 <term><option>-i
</option> <replaceable>INTERFACE
</replaceable></term>
197 <term><option>--interface=
</option><replaceable>INTERFACE
</replaceable></term>
199 <listitem><para>Specifies the network interface to execute the query on. This may either be specified as numeric
200 interface index or as network interface string (e.g.
<literal>en0
</literal>). Note that this option has no
201 effect if system-wide DNS configuration (as configured in
<filename>/etc/resolv.conf
</filename> or
202 <filename>/etc/systemd/resolve.conf
</filename>) in place of per-link configuration is used.
</para></listitem>
206 <term><option>-p
</option> <replaceable>PROTOCOL
</replaceable></term>
207 <term><option>--protocol=
</option><replaceable>PROTOCOL
</replaceable></term>
209 <listitem><para>Specifies the network protocol for the query. May be one of
<literal>dns
</literal>
210 (i.e. classic unicast DNS),
<literal>llmnr
</literal> (
<ulink
211 url=
"https://tools.ietf.org/html/rfc4795">Link-Local Multicast Name Resolution
</ulink>),
212 <literal>llmnr-ipv4
</literal>,
<literal>llmnr-ipv6
</literal> (LLMNR via the indicated underlying IP
213 protocols),
<literal>mdns
</literal> (
<ulink url=
"https://www.ietf.org/rfc/rfc6762.txt">Multicast DNS
</ulink>),
214 <literal>mdns-ipv4
</literal>,
<literal>mdns-ipv6
</literal> (MDNS via the indicated underlying IP protocols).
215 By default the lookup is done via all protocols suitable for the lookup. If used, limits the set of
216 protocols that may be used. Use this option multiple times to enable resolving via multiple protocols at the
217 same time. The setting
<literal>llmnr
</literal> is identical to specifying this switch once with
218 <literal>llmnr-ipv4
</literal> and once via
<literal>llmnr-ipv6
</literal>. Note that this option does not force
219 the service to resolve the operation with the specified protocol, as that might require a suitable network
220 interface and configuration.
221 The special value
<literal>help
</literal> may be used to list known values.
226 <term><option>-t
</option> <replaceable>TYPE
</replaceable></term>
227 <term><option>--type=
</option><replaceable>TYPE
</replaceable></term>
228 <term><option>-c
</option> <replaceable>CLASS
</replaceable></term>
229 <term><option>--class=
</option><replaceable>CLASS
</replaceable></term>
231 <listitem><para>Specifies the DNS resource record type (e.g. A, AAAA, MX, …) and class (e.g. IN, ANY, …) to
232 look up. If these options are used a DNS resource record set matching the specified class and type is
233 requested. The class defaults to IN if only a type is specified.
234 The special value
<literal>help
</literal> may be used to list known values.
239 <term><option>--service-address=
</option><replaceable>BOOL
</replaceable></term>
241 <listitem><para>Takes a boolean parameter. If true (the default), when doing a service lookup with
242 <option>--service
</option> the hostnames contained in the SRV resource records are resolved as well.
</para></listitem>
246 <term><option>--service-txt=
</option><replaceable>BOOL
</replaceable></term>
248 <listitem><para>Takes a boolean parameter. If true (the default), when doing a DNS-SD service lookup with
249 <option>--service
</option> the TXT service metadata record is resolved as well.
</para></listitem>
253 <term><option>--cname=
</option><replaceable>BOOL
</replaceable></term>
255 <listitem><para>Takes a boolean parameter. If true (the default), DNS CNAME or DNAME redirections are
256 followed. Otherwise, if a CNAME or DNAME record is encountered while resolving, an error is
257 returned.
</para></listitem>
261 <term><option>--search=
</option><replaceable>BOOL
</replaceable></term>
263 <listitem><para>Takes a boolean parameter. If true (the default), any specified single-label hostnames will be
264 searched in the domains configured in the search domain list, if it is non-empty. Otherwise, the search domain
265 logic is disabled.
</para></listitem>
269 <term><option>--raw
</option><optional>=payload|packet
</optional></term>
271 <listitem><para>Dump the answer as binary data. If there is no argument or if the argument is
272 <literal>payload
</literal>, the payload of the packet is exported. If the argument is
273 <literal>packet
</literal>, the whole packet is dumped in wire format, prefixed by
274 length specified as a little-endian
64-bit number. This format allows multiple packets
275 to be dumped and unambiguously parsed.
</para></listitem>
279 <term><option>--legend=
</option><replaceable>BOOL
</replaceable></term>
281 <listitem><para>Takes a boolean parameter. If true (the default), column headers and meta information about the
282 query response are shown. Otherwise, this output is suppressed.
</para></listitem>
285 <xi:include href=
"standard-options.xml" xpointer=
"help" />
286 <xi:include href=
"standard-options.xml" xpointer=
"version" />
287 <xi:include href=
"standard-options.xml" xpointer=
"no-pager" />
292 <title>Compatibility with
293 <citerefentry project=
"debian"><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry></title>
295 <para><command>resolvectl
</command> is a multi-call binary. When invoked as
<literal>resolvconf
</literal>
296 (generally achieved by means of a symbolic link of this name to the
<command>resolvectl
</command> binary) it
298 <citerefentry project=
"debian"><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
299 compatibility mode. It accepts mostly the same arguments and pushes all data into
300 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
301 similar to how
<option>dns
</option> and
<option>domain
</option> commands operate. Note that
302 <command>systemd-resolved.service
</command> is the only supported backend, which is different from other
303 implementations of this command.
</para>
305 <para><filename>/etc/resolv.conf
</filename> will only be updated with servers added with this command
306 when
<filename>/etc/resolv.conf
</filename> is a symlink to
307 <filename>/run/systemd/resolve/resolv.conf
</filename>, and not a static file. See the discussion of
308 <filename>/etc/resolv.conf
</filename> handling in
309 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
312 <para>Not all operations supported by other implementations are supported natively. Specifically:
</para>
316 <term><option>-a
</option></term>
317 <listitem><para>Registers per-interface DNS configuration data with
318 <command>systemd-resolved
</command>. Expects a network interface name as only command line argument. Reads
319 <citerefentry><refentrytitle>resolv.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry> compatible DNS
320 configuration data from its standard input. Relevant fields are
<literal>nameserver
</literal> and
321 <literal>domain
</literal>/
<literal>search
</literal>. This command is mostly identical to invoking
322 <command>resolvectl
</command> with a combination of
<option>dns
</option> and
323 <option>domain
</option> commands.
</para></listitem>
327 <term><option>-d
</option></term>
328 <listitem><para>Unregisters per-interface DNS configuration data with
<command>systemd-resolved
</command>. This
329 command is mostly identical to invoking
<command>resolvectl revert
</command>.
</para></listitem>
333 <term><option>-f
</option></term>
335 <listitem><para>When specified
<option>-a
</option> and
<option>-d
</option> will not complain about missing
336 network interfaces and will silently execute no operation in that case.
</para></listitem>
340 <term><option>-x
</option></term>
342 <listitem><para>This switch for
"exclusive" operation is supported only partially. It is mapped to an
343 additional configured search domain of
<literal>~.
</literal> — i.e. ensures that DNS traffic is preferably
344 routed to the DNS servers on this interface, unless there are other, more specific domains configured on other
345 interfaces.
</para></listitem>
349 <term><option>-m
</option></term>
350 <term><option>-p
</option></term>
352 <listitem><para>These switches are not supported and are silently ignored.
</para></listitem>
356 <term><option>-u
</option></term>
357 <term><option>-I
</option></term>
358 <term><option>-i
</option></term>
359 <term><option>-l
</option></term>
360 <term><option>-R
</option></term>
361 <term><option>-r
</option></term>
362 <term><option>-v
</option></term>
363 <term><option>-V
</option></term>
364 <term><option>--enable-updates
</option></term>
365 <term><option>--disable-updates
</option></term>
366 <term><option>--are-updates-enabled
</option></term>
368 <listitem><para>These switches are not supported and the command will fail if used.
</para></listitem>
374 <citerefentry project=
"debian"><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>
375 for details on those command line options.
</para>
379 <title>Examples
</title>
382 <title>Retrieve the addresses of the
<literal>www
.0pointer.net
</literal> domain
</title>
384 <programlisting>$ resolvectl query www
.0pointer.net
385 www
.0pointer.net:
2a01:
238:
43ed:c300:
10c3:bcf3:
3266:da74
388 -- Information acquired via protocol DNS in
611.6ms.
389 -- Data is authenticated: no
394 <title>Retrieve the domain of the
<literal>85.214.157.71</literal> IP address
</title>
396 <programlisting>$ resolvectl query
85.214.157.71
397 85.214.157.71: gardel
.0pointer.net
399 -- Information acquired via protocol DNS in
1.2997s.
400 -- Data is authenticated: no
405 <title>Retrieve the MX record of the
<literal>yahoo.com
</literal> domain
</title>
407 <programlisting>$ resolvectl --legend=no -t MX query yahoo.com
408 yahoo.com. IN MX
1 mta7.am0.yahoodns.net
409 yahoo.com. IN MX
1 mta6.am0.yahoodns.net
410 yahoo.com. IN MX
1 mta5.am0.yahoodns.net
415 <title>Resolve an SRV service
</title>
417 <programlisting>$ resolvectl service _xmpp-server._tcp gmail.com
418 _xmpp-server._tcp/gmail.com: alt1.xmpp-server.l.google.com:
5269 [priority=
20, weight=
0]
420 alt4.xmpp-server.l.google.com:
5269 [priority=
20, weight=
0]
427 <title>Retrieve a PGP key
</title>
429 <programlisting>$ resolvectl openpgp zbyszek@fedoraproject.org
430 d08ee310438ca124a6149ea5cc21b6313b390dce485576eff96f8722._openpgpkey.fedoraproject.org. IN OPENPGPKEY
431 mQINBFBHPMsBEACeInGYJCb+
7TurKfb6wGyTottCDtiSJB310i37/
6ZYoeIay/
5soJjlMyf
432 MFQ9T2XNT/
0LM
6gTa
0MpC
1st
9LnzYTMsT
6tzRly
1D
1UbVI
6xw
0g
0vE
5y
2Cjk
3xUwAynCsSs
438 <title>Retrieve a TLS key (
<literal>tcp
</literal> and
439 <literal>:
443</literal> could be skipped)
</title>
441 <programlisting>$ resolvectl tlsa tcp fedoraproject.org:
443
442 _443._tcp.fedoraproject.org IN TLSA
0 0 1 19400be5b7a31fb733917700789d2f0a2471c0c9d506c0e504c06c16d7cb17c0
443 -- Cert. usage: CA constraint
444 -- Selector: Full Certificate
445 -- Matching type: SHA-
256
451 <title>See Also
</title>
453 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
454 <citerefentry><refentrytitle>systemd-resolved.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
455 <citerefentry><refentrytitle>systemd.dnssd
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
456 <citerefentry><refentrytitle>systemd-networkd.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
457 <citerefentry><refentrytitle>resolvconf
</refentrytitle><manvolnum>8</manvolnum></citerefentry>