systemd-resolve

RESOLVECTL(1)                     resolvectl                     RESOLVECTL(1)

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

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

DESCRIPTION
       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" host name or all data from
       /etc/hosts.

COMMANDS
       query HOSTNAME|ADDRESS...
           Resolve domain names, IPv4 and IPv6 addresses.

       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. 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.

OPTIONS
       -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/resolve.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
           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.

       --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.

       --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.

       --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)
       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.
       Note that 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 this command line options.

BACKWARDS COMPATIBILITY WITH SYSTEMD-RESOLVE
       resolvectl is a multi-call binary, which previously was named
       "systemd-resolve" and used slightly different parameters. When it is
       invoked as "systemd-resolve" (generally achieved by means of a symbolic
       link of this name to the resolvectl binary), it runs in compatibility
       mode. For details on the specific parameters and calling syntax, see
       the output from systemd-resolve --help. Calling the binary as
       "systemd-resolve" is deprecated and should only be done for backwards
       compatibility. All current and new use should call the binary as
       "resolvectl".

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

NOTES
        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

systemd 245                                                      RESOLVECTL(1)
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