RESOLVECTL(1) resolvectl RESOLVECTL(1)
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 addresses 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.
monitor
Show a continuous stream of local client resolution queries and
their responses. Whenever a local query is completed the query's
DNS resource lookup key and resource records are shown. Note that
this displays queries issued locally only, and does not immediately
relate to DNS requests submitted to configured DNS servers or the
LLMNR or MulticastDNS zones, as lookups may be answered from the
local cache, or might result in multiple DNS transactions (for
example to validate DNSSEC information). If CNAME/CNAME redirection
chains are followed, a separate query will be displayed for each
element of the chain. Use --json= to enable JSON output.
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.
--json=MODE
Shows output formatted as JSON. Expects one of "short" (for the
shortest possible output without any redundant whitespace or line
breaks), "pretty" (for a pretty version of the same, with
indentation and line breaks) or "off" (to turn off JSON output, the
default).
-j
Short for --json=auto
--no-pager
Do not pipe output into a pager.
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
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
systemd 252 RESOLVECTL(1)
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