|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | COMMANDS | OPTIONS | COMPATIBILITY WITH RESOLVCONF(8) | EXAMPLES | SEE ALSO | NOTES | COLOPHON |
|
|
|
RESOLVECTL(1) resolvectl RESOLVECTL(1)
resolvectl, resolvconf - Resolve domain names, IPV4 and IPv6
addresses, DNS resource records, and services; introspect and
reconfigure the DNS resolver
resolvectl [OPTIONS...] {COMMAND} [NAME...]
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.
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.
If combined with --json= (only supported in combination with
--type=) will output the resource record data in a JSON
object.
Added in version 239.
service [[NAME] TYPE] DOMAIN
Resolve RFC 6763 DNS-SD[1] and RFC 2782 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).
Added in version 239.
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.
Added in version 239.
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.
Added in version 239.
status [LINK...]
Shows the global and per-link DNS settings currently in
effect. If no command is specified, this is the implied
default.
Added in version 239.
statistics
Shows general resolver statistics, including information
whether DNSSEC is enabled and available, as well as
resolution and validation statistics.
Added in version 239.
reset-statistics
Resets the statistics counters shown in statistics to zero.
This operation requires root privileges.
Added in version 239.
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.
Added in version 239.
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.
Added in version 239.
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).
Added in version 239.
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.
Added in version 239.
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.
Added in version 252.
show-cache
Show current cache content, per scope. Use --json= to enable
JSON output.
Added in version 254.
show-server-state
Show detailed server state information, per DNS Server. Use
--json= to enable JSON output.
Added in version 255.
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)).
Added in version 244.
-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.
Added in version 239.
-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.
Added in version 239.
-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.
Added in version 239.
-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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 248.
--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", "_outbound",
"_localdnsstub" and "_localdnsproxy" 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).
Added in version 248.
--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.
Added in version 248.
--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.
Added in version 248.
--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.
Added in version 248.
--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.
Added in version 248.
--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.
Added in version 239.
--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.
Added in version 239.
--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.
Added in version 239.
--stale-data=BOOL
Takes a boolean parameter; used in conjunction with query. If
true (the default), lookups are answered with stale data
(expired resource records) if possible. If false, the stale
data is not considered for the lookup request.
Added in version 254.
--relax-single-label=BOOL
Takes a boolean parameter; used in conjunction with query. If
true, rules regarding routing of single-label names are
relaxed. Defaults to false. By default, lookups of single
label names are assumed to refer to local hosts to be
resolved via local resolution such as LLMNR or via search
domain qualification and are not routed to upstream servers
as is. If this option is enabled these rules are disabled and
the queries are routed upstream anyway. Also see the
ResolveUnicastSingleLabel= option in resolved.conf(5) which
provides a system-wide option that controls this behaviour.
Added in version 256.
--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
Equivalent to --json=pretty if running on a terminal, and
--json=short otherwise.
--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.
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.
Added in version 239.
-d
Unregisters per-interface DNS configuration data with
systemd-resolved. This command is mostly identical to
invoking resolvectl revert.
Added in version 239.
-f
When specified -a and -d will not complain about missing
network interfaces and will silently execute no operation in
that case.
Added in version 239.
-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.
Added in version 239.
-m, -p
These switches are not supported and are silently ignored.
Added in version 239.
-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.
Added in version 239.
See resolvconf(8) for details on those command line options.
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.
systemd(1), systemd-resolved.service(8), systemd.dnssd(5),
systemd-networkd.service(8), resolvconf(8)
1. RFC 6763 DNS-SD
https://tools.ietf.org/html/rfc6763
2. RFC 2782 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
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 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) 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 improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 257~devel RESOLVECTL(1)
Pages that refer to this page: systemd.dnssd(5), systemd.link(5), systemd.directives(7), systemd.index(7), systemd-resolved.service(8)
|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|