jammy (1) resolvectl.1.gz

Provided by: systemd_249.11-0ubuntu3.12_amd64 bug

NAME

       resolvectl, resolvconf - 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" hostname or all data from /etc/hosts.

COMMANDS

       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 resource record 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 resource records, see RFC 7929[3]. 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 resource records, see RFC 6698[4]. 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

       -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)

       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

       Example 1. Retrieve the addresses of the "www.0pointer.net" domain (A and AAAA resource records)

           $ 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 (PTR resource record)

           $ 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 (OPENPGP resource record)

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

       Example 6. Retrieve a TLS key (TLSA resource record)

           $ 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

       "tcp" and ":443" are optional and could be skipped.

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. RFC 7929
           https://tools.ietf.org/html/rfc7929

        4. RFC 6698
           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