SYSTEMD-RESOLVE(1)systemd-resolveSYSTEMD-RESOLVE(1)NAMEsystemd-resolve - Resolve domain names, IPV4 and IPv6 addresses, DNS
resource records, and services
SYNOPSISsystemd-resolve [OPTIONS...] HOSTNAME...
systemd-resolve [OPTIONS...] ADDRESS...
systemd-resolve [OPTIONS...] --type=TYPE DOMAIN...
systemd-resolve [OPTIONS...] --service [[NAME] TYPE] DOMAIN
systemd-resolve [OPTIONS...] --openpgp USER@DOMAIN
systemd-resolve [OPTIONS...] --tlsa DOMAIN[:PORT]
systemd-resolve [OPTIONS...] --statistics
systemd-resolve [OPTIONS...] --reset-statistics
DESCRIPTIONsystemd-resolve 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.
The --type= switch may be used to specify a DNS resource record type
(A, AAAA, SOA, MX, ...) in order to request a specific DNS resource
record, instead of the address or reverse address lookups. The special
value "help" may be used to list known values.
The --service switch may be used to resolve SRV[1] and DNS-SD[2]
services (see below). In this mode, between one and three arguments are
required. 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).
The --openpgp switch may be used to query PGP keys stored as
OPENPGPKEY[3] resource records. When this option is specified one or
more e-mail address must be specified.
The --tlsa switch maybe be used to query TLS public keys stored as
TLSA[4] resource records. When this option is specified one or more
domain names must be specified.
The --statistics switch may be used to show resolver statistics,
including information about the number of successful and failed DNSSEC
validations.
The --reset-statistics may be used to reset various statistics counters
maintained the resolver, including those shown in the --statistics
output. This operation requires root privileges.
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
Enables service resolution. This enables DNS-SD and simple SRV
service resolution, depending on the specified list of parameters
(see above).
--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.
--openpgp
Enables OPENPGPKEY resource record resolution (see above).
Specified e-mail addresses are converted to the corresponding DNS
domain name, and any OPENPGPKEY keys are printed.
--tlsa
Enables TLSA resource record resolution (see above). 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 an argument after --tlsa,
otherwise tcp will be used.
--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.
--statistics
If specified general resolver statistics are shown, 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.
--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.
--status
Shows the global and per-link DNS settings in currently in effect.
--set-dns=SERVER, --set-domain=DOMAIN, --set-llmnr=MODE,
--set-mdns=MODE, --set-dnssec=MODE, --set-nta=DOMAIN
Set per-interface DNS configuration. These switches may be used to
configure various DNS settings for network interfaces that aren't
managed by systemd-networkd.service(8). (These commands will fail
when used on interfaces that are managed by systemd-networkd,
please configure their DNS settings directly inside the .network
files instead.) These switches may be used to inform
systemd-resolved about per-interface DNS configuration determined
through external means. Multiple of these switches may be passed on
a single invocation of systemd-resolve in order to set multiple
configuration options at once. If any of these switches is used, it
must be combined with --interface= to indicate the network
interface the new DNS configuration belongs to. The --set-dns=
option expects an IPv4 or IPv6 address specification of a DNS
server to use, and may be used multiple times to define multiple
servers for the same interface. The --set-domain= option expects a
valid DNS domain, possibly prefixed with "~", and configures a
per-interface search or route-only domain. It may be used multiple
times to configure multiple such domains. The --set-llmnr=,
--set-mdns= and --set-dnssec= options may be used to configure the
per-interface LLMNR, MulticastDNS and DNSSEC settings. Finally,
--set-nta= may be used to configure additional per-interface DNSSEC
NTA domains and may also be used multiple times. For details about
these settings, their possible values and their effect, see the
corresponding options in systemd.network(5).
--revert
Revert the per-interface DNS configuration. This option must be
combined with --interface= to indicate the network interface the
DNS configuration shall be reverted on. If the DNS configuration is
reverted all per-interface DNS setting are reset to their defaults,
undoing all effects of --set-dns=, --set-domain=, --set-llmnr=,
--set-mdns=, --set-dnssec=, --set-nta=. Note that when a network
interface disappears all configuration is lost automatically, an
explicit reverting is not necessary in that case.
-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.
EXAMPLES
Example 1. Retrieve the addresses of the "www.0pointer.net" domain
$ systemd-resolve 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
$ systemd-resolve 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
$ systemd-resolve-t MX yahoo.com --legend=no
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
$ systemd-resolve--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
$ systemd-resolve--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)
$ systemd-resolve --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 ALSOsystemd(1), systemd-resolved.service(8), systemd.dnssd(5), systemd-
networkd.service(8)NOTES
1. SRV
https://tools.ietf.org/html/rfc2782
2. DNS-SD
https://tools.ietf.org/html/rfc6763
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 236SYSTEMD-RESOLVE(1)
