Ubuntu Manpage: systemd-resolve - Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services

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synopsis
description
options
examples
see also
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Provided by: systemd_229-4ubuntu21.31_amd64

NAME

       systemd-resolve - Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services

SYNOPSIS

       systemd-resolve [OPTIONS...] HOSTNAME...

       systemd-resolve [OPTIONS...] ADDRESS...

       systemd-resolve [OPTIONS...] --type=TYPE RRDOMAIN...

       systemd-resolve [OPTIONS...] --service [[NAME] TYPE] DOMAIN

       systemd-resolve [OPTIONS...] --statistics

       systemd-resolve [OPTIONS...] --reset-statistics

DESCRIPTION

systemd-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 --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 --statistics switch may be used to show resolver statistics, including information about the number
of succesful 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[3]), "llmr-ipv4", "llmnr-ipv6" (LLMNR 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.

--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.

--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.

-h, --help
Print a short help text and exit.

--version
Print a short version string and exit.

EXAMPLES

       Example 1. Retrieve the addresses of the "www.0pointer.net" domain

           $ systemd-resolve www.0pointer.net

       Example 2. Retrieve the domain of the "85.214.157.71" IP address

           $ systemd-resolve 85.214.157.71

       Example 3. Retrieve the MX record of the "0pointer.net" domain

           $ systemd-resolve -t MX 0pointer.net

       Example 4. Resolve an SRV service

           $ systemd-resolve --service _xmpp-server._tcp gmail.com

NOTES

        1. SRV
           https://tools.ietf.org/html/rfc2782

        2. DNS-SD
           https://tools.ietf.org/html/rfc6763

        3. Link-Local Multicast Name Resolution
           https://tools.ietf.org/html/rfc4795