resolvconf(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, 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.

       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/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)         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 2020-07-14.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-07-14.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
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       of the original manual page), send a mail to man-pages@man7.org

systemd 246                                                    RESOLVECTL(1)

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