resolvectl(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | COMPATIBILITY WITH RESOLVCONF(8) | EXAMPLES | SEE ALSO | NOTES | COLOPHON

RESOLVECTL(1)                  resolvectl                  RESOLVECTL(1)

NAME         top

       resolvectl, resolvconf - Resolve domain names, IPV4 and IPv6
       addresses, DNS resource records, and services; introspect and
       reconfigure the DNS resolver

SYNOPSIS         top

       resolvectl [OPTIONS...] {COMMAND} [NAME...]

DESCRIPTION         top

       resolvectl may be used to resolve domain names, IPv4 and IPv6
       addresses, DNS resource records and services with the
       systemd-resolved.service(8) 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.

       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
       "localhost" hostname or all data from /etc/hosts.

COMMANDS         top

       query HOSTNAME|ADDRESS...
           Resolve domain names, as well as IPv4 and IPv6 addresses.
           When used in conjunction with --type= or --class= (see
           below), resolves low-level DNS resource records.

           If a single-label domain name is specified it is searched for
           according to the configured search domains — unless
           --search=no or --type=/--class= are specified, both of which
           turn this logic off.

           If an international domain name is specified, it is
           automatically translated according to IDNA rules when
           resolved via classic DNS — but not for look-ups via
           MulticastDNS or LLMNR. If --type=/--class= is used IDNA
           translation is turned off and domain names are processed as
           specified.

       service [[NAME] TYPE] DOMAIN
           Resolve DNS-SD[1] and SRV[2] services, depending on the
           specified list of parameters. 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).

       openpgp EMAIL@DOMAIN...
           Query PGP keys stored as OPENPGPKEY[3] resource records.
           Specified e-mail addresses are converted to the corresponding
           DNS domain name, and any OPENPGPKEY keys are printed.

       tlsa [FAMILY] DOMAIN[:PORT]...
           Query TLS public keys stored as TLSA[4] resource records. A
           query will be performed for each of the specified names
           prefixed with the port and family ("_port._family.domain").
           The port number may be specified after a colon (":"),
           otherwise 443 will be used by default. The family may be
           specified as the first argument, otherwise tcp will be used.

       status [LINK...]
           Shows the global and per-link DNS settings currently in
           effect. If no command is specified, this is the implied
           default.

       statistics
           Shows general resolver statistics, including information
           whether DNSSEC is enabled and available, as well as
           resolution and validation statistics.

       reset-statistics
           Resets the statistics counters shown in statistics to zero.
           This operation requires root privileges.

       flush-caches
           Flushes all DNS resource record caches the service maintains
           locally. This is mostly equivalent to sending the SIGUSR2 to
           the systemd-resolved service.

       reset-server-features
           Flushes all feature level information the resolver learnt
           about specific servers, and ensures that the server feature
           probing logic is started from the beginning with the next
           look-up request. This is mostly equivalent to sending the
           SIGRTMIN+1 to the systemd-resolved service.

       dns [LINK [SERVER...]], domain [LINK [DOMAIN...]], default-route
       [LINK [BOOL...]], llmnr [LINK [MODE]], mdns [LINK [MODE]], dnssec
       [LINK [MODE]], dnsovertls [LINK [MODE]], nta [LINK [DOMAIN...]]
           Get/set per-interface DNS configuration. These commands may
           be used to configure various DNS settings for network
           interfaces. These commands may be used to inform
           systemd-resolved or systemd-networkd about per-interface DNS
           configuration determined through external means. The dns
           command expects IPv4 or IPv6 address specifications of DNS
           servers to use. Each address can optionally take a port
           number separated with ":", a network interface name or index
           separated with "%", and a Server Name Indication (SNI)
           separated with "#". When IPv6 address is specified with a
           port number, then the address must be in the square brackets.
           That is, the acceptable full formats are
           "111.222.333.444:9953%ifname#example.com" for IPv4 and
           "[1111:2222::3333]:9953%ifname#example.com" for IPv6. The
           domain command expects valid DNS domains, possibly prefixed
           with "~", and configures a per-interface search or route-only
           domain. The default-route command expects a boolean
           parameter, and configures whether the link may be used as
           default route for DNS lookups, i.e. if it is suitable for
           lookups on domains no other link explicitly is configured
           for. The llmnr, mdns, dnssec and dnsovertls commands may be
           used to configure the per-interface LLMNR, MulticastDNS,
           DNSSEC and DNSOverTLS settings. Finally, nta command may be
           used to configure additional per-interface DNSSEC NTA
           domains.

           Commands dns, domain and nta can take a single empty string
           argument to clear their respective value lists.

           For details about these settings, their possible values and
           their effect, see the corresponding settings in
           systemd.network(5).

       revert LINK
           Revert the per-interface DNS configuration. If the DNS
           configuration is reverted all per-interface DNS setting are
           reset to their defaults, undoing all effects of dns, domain,
           default-route, llmnr, mdns, dnssec, dnsovertls, nta. Note
           that when a network interface disappears all configuration is
           lost automatically, an explicit reverting is not necessary in
           that case.

       log-level [LEVEL]
           If no argument is given, print the current log level of the
           manager. If an optional argument LEVEL is provided, then the
           command changes the current log level of the manager to LEVEL
           (accepts the same values as --log-level= described in
           systemd(1)).

OPTIONS         top

       -4, -6
           By default, when resolving a hostname, both IPv4 and IPv6
           addresses are acquired. By specifying -4 only IPv4 addresses
           are requested, by specifying -6 only IPv6 addresses are
           requested.

       -i INTERFACE, --interface=INTERFACE
           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.  "en0"). Note that this option
           has no effect if system-wide DNS configuration (as configured
           in /etc/resolv.conf or /etc/systemd/resolved.conf) in place
           of per-link configuration is used.

       -p PROTOCOL, --protocol=PROTOCOL
           Specifies the network protocol for the query. May be one of
           "dns" (i.e. classic unicast DNS), "llmnr" (Link-Local
           Multicast Name Resolution[5]), "llmnr-ipv4", "llmnr-ipv6"
           (LLMNR via the indicated underlying IP protocols), "mdns"
           (Multicast DNS[6]), "mdns-ipv4", "mdns-ipv6" (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 "llmnr" is identical to specifying
           this switch once with "llmnr-ipv4" and once via "llmnr-ipv6".
           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 "help" may be used to list known values.

       -t TYPE, --type=TYPE, -c CLASS, --class=CLASS
           When used in conjunction with the query command, 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 "help" may be used to
           list known values.

           Without these options resolvectl query provides high-level
           domain name to address and address to domain name resolution.
           With these options it provides low-level DNS resource record
           resolution. The search domain logic is automatically turned
           off when these options are used, i.e. specified domain names
           need to be fully qualified domain names. Moreover, IDNA
           internal domain name translation is turned off as well, i.e.
           international domain names should be specified in "xn--..."
           notation, unless look-up in MulticastDNS/LLMNR is desired, in
           which case UTF-8 characters should be used.

       --service-address=BOOL
           Takes a boolean parameter. If true (the default), when doing
           a service lookup with --service the hostnames contained in
           the SRV resource records are resolved as well.

       --service-txt=BOOL
           Takes a boolean parameter. If true (the default), when doing
           a DNS-SD service lookup with --service the TXT service
           metadata record is resolved as well.

       --cname=BOOL
           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.

       --validate=BOOL
           Takes a boolean parameter; used in conjunction with query. If
           true (the default), DNSSEC validation is applied as usual —
           under the condition that it is enabled for the network and
           for systemd-resolved.service as a whole. If false, DNSSEC
           validation is disabled for the specific query, regardless of
           whether it is enabled for the network or in the service. Note
           that setting this option to true does not force DNSSEC
           validation on systems/networks where DNSSEC is turned off.
           This option is only suitable to turn off such validation
           where otherwise enabled, not enable validation where
           otherwise disabled.

       --synthesize=BOOL
           Takes a boolean parameter; used in conjunction with query. If
           true (the default), select domains are resolved on the local
           system, among them "localhost", "_gateway" and "_outbound",
           or entries from /etc/hosts. If false these domains are not
           resolved locally, and either fail (in case of "localhost",
           "_gateway" or "_outbound" and suchlike) or go to the network
           via regular DNS/mDNS/LLMNR lookups (in case of /etc/hosts
           entries).

       --cache=BOOL
           Takes a boolean parameter; used in conjunction with query. If
           true (the default), lookups use the local DNS resource record
           cache. If false, lookups are routed to the network instead,
           regardless if already available in the local cache.

       --zone=BOOL
           Takes a boolean parameter; used in conjunction with query. If
           true (the default), lookups are answered from locally
           registered LLMNR or mDNS resource records, if defined. If
           false, locally registered LLMNR/mDNS records are not
           considered for the lookup request.

       --trust-anchor=BOOL
           Takes a boolean parameter; used in conjunction with query. If
           true (the default), lookups for DS and DNSKEY are answered
           from the local DNSSEC trust anchors if possible. If false,
           the local trust store is not considered for the lookup
           request.

       --network=BOOL
           Takes a boolean parameter; used in conjunction with query. If
           true (the default), lookups are answered via DNS, LLMNR or
           mDNS network requests if they cannot be synthesized locally,
           or be answered from the local cache, zone or trust anchors
           (see above). If false, the request is not answered from the
           network and will thus fail if none of the indicated sources
           can answer them.

       --search=BOOL
           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.
           Note that this option has no effect if --type= is used (see
           above), in which case the search domain logic is
           unconditionally turned off.

       --raw[=payload|packet]
           Dump the answer as binary data. If there is no argument or if
           the argument is "payload", the payload of the packet is
           exported. If the argument is "packet", 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.

       --legend=BOOL
           Takes a boolean parameter. If true (the default), column
           headers and meta information about the query response are
           shown. Otherwise, this output is suppressed.

       -h, --help
           Print a short help text and exit.

       --version
           Print a short version string and exit.

       --no-pager
           Do not pipe output into a pager.

COMPATIBILITY WITH RESOLVCONF(8)         top

       resolvectl is a multi-call binary. When invoked as "resolvconf"
       (generally achieved by means of a symbolic link of this name to
       the resolvectl binary) it is run in a limited resolvconf(8)
       compatibility mode. It accepts mostly the same arguments and
       pushes all data into systemd-resolved.service(8), similar to how
       dns and domain commands operate. Note that
       systemd-resolved.service is the only supported backend, which is
       different from other implementations of this command.

       /etc/resolv.conf will only be updated with servers added with
       this command when /etc/resolv.conf is a symlink to
       /run/systemd/resolve/resolv.conf, and not a static file. See the
       discussion of /etc/resolv.conf handling in
       systemd-resolved.service(8).

       Not all operations supported by other implementations are
       supported natively. Specifically:

       -a
           Registers per-interface DNS configuration data with
           systemd-resolved. Expects a network interface name as only
           command line argument. Reads resolv.conf(5)-compatible DNS
           configuration data from its standard input. Relevant fields
           are "nameserver" and "domain"/"search". This command is
           mostly identical to invoking resolvectl with a combination of
           dns and domain commands.

       -d
           Unregisters per-interface DNS configuration data with
           systemd-resolved. This command is mostly identical to
           invoking resolvectl revert.

       -f
           When specified -a and -d will not complain about missing
           network interfaces and will silently execute no operation in
           that case.

       -x
           This switch for "exclusive" operation is supported only
           partially. It is mapped to an additional configured search
           domain of "~."  — i.e. ensures that DNS traffic is preferably
           routed to the DNS servers on this interface, unless there are
           other, more specific domains configured on other interfaces.

       -m, -p
           These switches are not supported and are silently ignored.

       -u, -I, -i, -l, -R, -r, -v, -V, --enable-updates,
       --disable-updates, --are-updates-enabled
           These switches are not supported and the command will fail if
           used.

       See resolvconf(8) for details on those command line options.

EXAMPLES         top

       Example 1. Retrieve the addresses of the "www.0pointer.net"
       domain

           $ resolvectl query 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

       Example 2. Retrieve the domain of the "85.214.157.71" IP address

           $ resolvectl query 85.214.157.71
           85.214.157.71: gardel.0pointer.net

           -- Information acquired via protocol DNS in 1.2997s.
           -- Data is authenticated: no

       Example 3. Retrieve the MX record of the "yahoo.com" domain

           $ resolvectl --legend=no -t MX query yahoo.com
           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

       Example 4. Resolve an SRV service

           $ resolvectl 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
                                        ...

       Example 5. Retrieve a PGP key

           $ resolvectl openpgp zbyszek@fedoraproject.org
           d08ee310438ca124a6149ea5cc21b6313b390dce485576eff96f8722._openpgpkey.fedoraproject.org. IN OPENPGPKEY
                   mQINBFBHPMsBEACeInGYJCb+7TurKfb6wGyTottCDtiSJB310i37/6ZYoeIay/5soJjlMyf
                   MFQ9T2XNT/0LM6gTa0MpC1st9LnzYTMsT6tzRly1D1UbVI6xw0g0vE5y2Cjk3xUwAynCsSs
                   ...

       Example 6. Retrieve a TLS key ("tcp" and ":443" could be skipped)

           $ resolvectl 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

SEE ALSO         top

       systemd(1), systemd-resolved.service(8), systemd.dnssd(5),
       systemd-networkd.service(8), resolvconf(8)

NOTES         top

        1. DNS-SD
           https://tools.ietf.org/html/rfc6763

        2. SRV
           https://tools.ietf.org/html/rfc2782

        3. OPENPGPKEY
           https://tools.ietf.org/html/rfc7929

        4. TLSA
           https://tools.ietf.org/html/rfc6698

        5. Link-Local Multicast Name Resolution
           https://tools.ietf.org/html/rfc4795

        6. Multicast DNS
           https://www.ietf.org/rfc/rfc6762.txt

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-06-20.  (At that
       time, the date of the most recent commit that was found in the
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       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 249                                                RESOLVECTL(1)

Pages that refer to this page: systemd.dnssd(5)systemd.directives(7)systemd.index(7)systemd-resolved.service(8)