org.freedesktop.resolve1(5) — Linux manual page

NAME | INTRODUCTION | THE MANAGER OBJECT | LINK OBJECT | COMMON ERRORS | EXAMPLES | VERSIONING | NOTES | COLOPHON

ORG.FREEDESKTOP.RESOLVE1(5).freedesktop.resolve1.FREEDESKTOP.RESOLVE1(5)

NAME         top

       org.freedesktop.resolve1 - The D-Bus interface of
       systemd-resolved

INTRODUCTION         top

       systemd-resolved.service(8) is a system service that provides
       hostname resolution and caching using DNS, LLMNR, and mDNS. It
       also does DNSSEC validation. This page describes the resolve
       semantics and the D-Bus interface.

       This page contains an API reference only. If you are looking for
       a longer explanation how to use this API, please consult Writing
       Network Configuration Managers[1] and Writing Resolver
       Clients[2].

THE MANAGER OBJECT         top

       The service exposes the following interfaces on the Manager
       object on the bus:

           node /org/freedesktop/resolve1 {
             interface org.freedesktop.resolve1.Manager {
               methods:
                 ResolveHostname(in  i ifindex,
                                 in  s name,
                                 in  i family,
                                 in  t flags,
                                 out a(iiay) addresses,
                                 out s canonical,
                                 out t flags);
                 ResolveAddress(in  i ifindex,
                                in  i family,
                                in  ay address,
                                in  t flags,
                                out a(is) names,
                                out t flags);
                 ResolveRecord(in  i ifindex,
                               in  s name,
                               in  q class,
                               in  q type,
                               in  t flags,
                               out a(iqqay) records,
                               out t flags);
                 ResolveService(in  i ifindex,
                                in  s name,
                                in  s type,
                                in  s domain,
                                in  i family,
                                in  t flags,
                                out a(qqqsa(iiay)s) srv_data,
                                out aay txt_data,
                                out s canonical_name,
                                out s canonical_type,
                                out s canonical_domain,
                                out t flags);
                 GetLink(in  i ifindex,
                         out o path);
                 SetLinkDNS(in  i ifindex,
                            in  a(iay) addresses);
                 SetLinkDNSEx(in  i ifindex,
                              in  a(iayqs) addresses);
                 SetLinkDomains(in  i ifindex,
                                in  a(sb) domains);
                 SetLinkDefaultRoute(in  i ifindex,
                                     in  b enable);
                 SetLinkLLMNR(in  i ifindex,
                              in  s mode);
                 SetLinkMulticastDNS(in  i ifindex,
                                     in  s mode);
                 SetLinkDNSOverTLS(in  i ifindex,
                                   in  s mode);
                 SetLinkDNSSEC(in  i ifindex,
                               in  s mode);
                 SetLinkDNSSECNegativeTrustAnchors(in  i ifindex,
                                                   in  as names);
                 RevertLink(in  i ifindex);
                 RegisterService(in  s name,
                                 in  s name_template,
                                 in  s type,
                                 in  q service_port,
                                 in  q service_priority,
                                 in  q service_weight,
                                 in  aa{say} txt_datas,
                                 out o service_path);
                 UnregisterService(in  o service_path);
                 ResetStatistics();
                 FlushCaches();
                 ResetServerFeatures();
               properties:
                 readonly s LLMNRHostname = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s LLMNR = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s MulticastDNS = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s DNSOverTLS = '...';
                 readonly a(iiay) DNS = [...];
                 readonly a(iiayqs) DNSEx = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
                 readonly a(iiay) FallbackDNS = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
                 readonly a(iiayqs) FallbackDNSEx = [...];
                 readonly (iiay) CurrentDNSServer = ...;
                 readonly (iiayqs) CurrentDNSServerEx = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly a(isb) Domains = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly (tt) TransactionStatistics = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly (ttt) CacheStatistics = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s DNSSEC = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly (tttt) DNSSECStatistics = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly b DNSSECSupported = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly as DNSSECNegativeTrustAnchors = ['...', ...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s DNSStubListener = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s ResolvConfMode = '...';
             };
             interface org.freedesktop.DBus.Peer { ... };
             interface org.freedesktop.DBus.Introspectable { ... };
             interface org.freedesktop.DBus.Properties { ... };
           };

   Methods
       ResolveHostname() takes a hostname and resolves it to one or more
       IP addresses. As parameters it takes the Linux network interface
       index to execute the query on, or 0 if it may be done on any
       suitable interface. The name parameter specifies the hostname to
       resolve. Note that if required, IDNA conversion is applied to
       this name unless it is resolved via LLMNR or MulticastDNS. The
       family parameter limits the results to a specific address family.
       It may be AF_INET, AF_INET6 or AF_UNSPEC. If AF_UNSPEC is
       specified (recommended), both kinds are retrieved, subject to
       local network configuration (i.e. if no local, routable IPv6
       address is found, no IPv6 address is retrieved; and similarly for
       IPv4). A 64-bit flags field may be used to alter the behaviour of
       the resolver operation (see below). The method returns an array
       of address records. Each address record consists of the interface
       index the address belongs to, an address family as well as a byte
       array with the actual IP address data (which either has 4 or 16
       elements, depending on the address family). The returned address
       family will be one of AF_INET or AF_INET6. For IPv6, the returned
       address interface index should be used to initialize the
       .sin6_scope_id field of a struct sockaddr_in6 instance to permit
       support for resolution to link-local IP addresses. The address
       array is followed by the canonical name of the host, which may or
       may not be identical to the resolved hostname. Finally, a 64-bit
       flags field is returned that is defined similarly to the flags
       field that was passed in, but contains information about the
       resolved data (see below). If the hostname passed in is an IPv4
       or IPv6 address formatted as string, it is parsed, and the result
       is returned. In this case, no network communication is done.

       ResolveAddress() executes the reverse operation: it takes an IP
       address and acquires one or more hostnames for it. As parameters
       it takes the interface index to execute the query on, or 0 if all
       suitable interfaces are OK. The family parameter indicates the
       address family of the IP address to resolve. It may be either
       AF_INET or AF_INET6. The address parameter takes the raw IP
       address data (as either a 4 or 16 byte array). The flags input
       parameter may be used to alter the resolver operation (see
       below). The method returns an array of name records, each
       consisting of an interface index and a hostname. The flags output
       field contains additional information about the resolver
       operation (see below).

       ResolveRecord() takes a DNS resource record (RR) type, class and
       name, and retrieves the full resource record set (RRset),
       including the RDATA, for it. As parameter it takes the Linux
       network interface index to execute the query on, or 0 if it may
       be done on any suitable interface. The name parameter specifies
       the RR domain name to look up (no IDNA conversion is applied),
       followed by the 16-bit class and type fields (which may be ANY).
       Finally, a flags field may be passed in to alter behaviour of the
       look-up (see below). On completion, an array of RR items is
       returned. Each array entry consists of the network interface
       index the RR was discovered on, the type and class field of the
       RR found, and a byte array of the raw RR discovered. The raw RR
       data starts with the RR's domain name, in the original casing,
       followed by the RR type, class, TTL and RDATA, in the binary
       format documented in RFC 1035[3]. For RRs that support name
       compression in the payload (such as MX or PTR), the compression
       is expanded in the returned data.

       Note that currently, the class field has to be specified as IN or
       ANY. Specifying a different class will return an error indicating
       that look-ups of this kind are unsupported. Similarly, some
       special types are not supported either (AXFR, OPT, ...). While
       systemd-resolved parses and validates resource records of many
       types, it is crucial that clients using this API understand that
       the RR data originates from the network and should be thoroughly
       validated before use.

       ResolveService() may be used to resolve a DNS SRV service record,
       as well as the hostnames referenced in it, and possibly an
       accompanying DNS-SD TXT record containing additional service
       metadata. The primary benefit of using this method over
       ResolveRecord() specifying the SRV type is that it will resolve
       the SRV and TXT RRs as well as the hostnames referenced in the
       SRV in a single operation. As parameters it takes a Linux network
       interface index, a service name, a service type and a service
       domain. This method may be invoked in three different modes:

        1. To resolve a DNS-SD service, specify the service name (e.g.
           "Lennart's Files"), the service type (e.g.  "_webdav._tcp")
           and the domain to search in (e.g.  "local") as the three
           service parameters. The service name must be in UTF-8 format,
           and no IDNA conversion is applied to it in this mode (as
           mandated by the DNS-SD specifications). However, if
           necessary, IDNA conversion is applied to the domain
           parameter.

        2. To resolve a plain SRV record, set the service name parameter
           to the empty string and set the service type and domain
           properly. (IDNA conversion is applied to the domain, if
           necessary.)

        3. Alternatively, leave both the service name and type empty and
           specify the full domain name of the SRV record (i.e. prefixed
           with the service type) in the domain parameter. (No IDNA
           conversion is applied in this mode.)

       The family parameter of the ResolveService() method encodes the
       desired family of the addresses to resolve (use AF_INET,
       AF_INET6, or AF_UNSPEC). If this is enabled (Use the NO_ADDRESS
       flag to turn address resolution off, see below). The flags
       parameter takes a couple of flags that may be used to alter the
       resolver operation.

       On completion, ResolveService() returns an array of SRV record
       structures. Each items consisting of the priority, weight and
       port fields as well as the hostname to contact, as encoded in the
       SRV record. Immediately following is an array of the addresses of
       this hostname, with each item consisting of the interface index,
       the address family and the address data in a byte array. This
       address array is followed by the canonicalized hostname. After
       this array of SRV record structures an array of byte arrays
       follows that encodes the TXT RR strings, in case DNS-SD look-ups
       are enabled. The next parameters are the canonical service name,
       type and domain. This may or may not be identical to the
       parameters passed in. Finally, a flags field is returned that
       contains information about the resolver operation performed.

       The ResetStatistics() method resets the various statistics
       counters that systemd-resolved maintains to zero. (For details,
       see the statistics properties below.)

       The GetLink() method takes a network interface index and returns
       the object path to the org.freedesktop.resolve1.Link object
       corresponding to it.

       The SetLinkDNS() method sets the DNS servers to use on a specific
       interface. This method (and the following ones) may be used by
       network management software to configure per-interface DNS
       settings. It takes a network interface index as well as an array
       of DNS server IP address records. Each array item consists of an
       address family (either AF_INET or AF_INET6), followed by a 4-byte
       or 16-byte array with the raw address data. This method is a
       one-step shortcut for retrieving the Link object for a network
       interface using GetLink() (see above) and then invoking the
       SetDNS() method (see below) on it.

       SetLinkDNSEx() is similar to SetLinkDNS(), but allows an IP port
       (instead of the default 53) and DNS name to be specified for each
       DNS server. The server name is used for Server Name Indication
       (SNI), which is useful when DNS-over-TLS is used. C.f.  DNS= in
       resolved.conf(5).

       SetLinkDefaultRoute() specifies whether the link shall be used as
       the default route for name queries. See the description of name
       routing in systemd-resolved.service(8) for details.

       The SetLinkDomains() method sets the search and routing domains
       to use on a specific network interface for DNS look-ups. It takes
       a network interface index and an array of domains, each with a
       boolean parameter indicating whether the specified domain shall
       be used as a search domain (false), or just as a routing domain
       (true). Search domains are used for qualifying single-label names
       into FQDN when looking up hostnames, as well as for making
       routing decisions on which interface to send queries ending in
       the domain to. Routing domains are only used for routing
       decisions and not used for single-label name qualification. Pass
       the search domains in the order they should be used.

       The SetLinkLLMNR() method enables or disables LLMNR support on a
       specific network interface. It takes a network interface index as
       well as a string that may either be empty or one of "yes", "no"
       or "resolve". If empty, the systemd-wide default LLMNR setting is
       used. If "yes", LLMNR is used for resolution of single-label
       names and the local hostname is registered on all local LANs for
       LLMNR resolution by peers. If "no", LLMNR is turned off fully on
       this interface. If "resolve", LLMNR is only enabled for resolving
       names, but the local hostname is not registered for other peers
       to use.

       Similarly, the SetLinkMulticastDNS() method enables or disables
       MulticastDNS support on a specific interface. It takes the same
       parameters as SetLinkLLMNR() described above.

       The SetLinkDNSSEC() method enables or disables DNSSEC validation
       on a specific network interface. It takes a network interface
       index as well as a string that may either be empty or one of
       "yes", "no", or "allow-downgrade". When empty, the system-wide
       default DNSSEC setting is used. If "yes", full DNSSEC validation
       is done for all look-ups. If the selected DNS server does not
       support DNSSEC, look-ups will fail if this mode is used. If "no",
       DNSSEC validation is fully disabled. If "allow-downgrade", DNSSEC
       validation is enabled, but is turned off automatically if the
       selected server does not support it (thus opening up behaviour to
       downgrade attacks). Note that DNSSEC only applies to traditional
       DNS, not to LLMNR or MulticastDNS.

       The SetLinkDNSSECNegativeTrustAnchors() method may be used to
       configure DNSSEC Negative Trust Anchors (NTAs) for a specific
       network interface. It takes a network interface index and a list
       of domains as arguments.

       The SetLinkDNSOverTLS() method enables or disables DNS-over-TLS.
       C.f.  DNSOverTLS= in systemd-resolved.service(8) for details.

       Network management software integrating with systemd-resolved
       should call SetLinkDNS() or SetLinkDNSEx(),
       SetLinkDefaultRoute(), SetLinkDomains() and others after the
       interface appeared in the kernel (and thus after a network
       interface index has been assigned), but before the network
       interfaces is activated (IFF_UP set) so that all settings take
       effect during the full time the network interface is up. It is
       safe to alter settings while the interface is up, however. Use
       RevertLink() (described below) to reset all per-interface
       settings.

       The RevertLink() method may be used to revert all per-link
       settings described above to the defaults.

       The Flags Parameter
           The four methods above accept and return a 64-bit flags
           value. In most cases passing 0 is sufficient and recommended.
           However, the following flags are defined to alter the
           look-up:

               #define SD_RESOLVED_DNS           (UINT64_C(1) << 0)
               #define SD_RESOLVED_LLMNR_IPV4    (UINT64_C(1) << 1)
               #define SD_RESOLVED_LLMNR_IPV6    (UINT64_C(1) << 2)
               #define SD_RESOLVED_MDNS_IPV4     (UINT64_C(1) << 3)
               #define SD_RESOLVED_MDNS_IPV6     (UINT64_C(1) << 4)
               #define SD_RESOLVED_NO_CNAME      (UINT64_C(1) << 5)
               #define SD_RESOLVED_NO_TXT        (UINT64_C(1) << 6)
               #define SD_RESOLVED_NO_ADDRESS    (UINT64_C(1) << 7)
               #define SD_RESOLVED_NO_SEARCH     (UINT64_C(1) << 8)
               #define SD_RESOLVED_AUTHENTICATED (UINT64_C(1) << 9)

           On input, the first five flags control the protocols to use
           for the look-up. They refer to classic unicast DNS, LLMNR via
           IPv4/UDP and IPv6/UDP respectively, as well as MulticastDNS
           via IPv4/UDP and IPv6/UDP. If all of these five bits are off
           on input (which is strongly recommended) the look-up will be
           done via all suitable protocols for the specific look-up.
           Note that these flags operate as filter only, but cannot
           force a look-up to be done via a protocol. Specifically,
           systemd-resolved will only route look-ups within the .local
           TLD to MulticastDNS (plus some reverse look-up address
           domains), and single-label names to LLMNR (plus some reverse
           address lookup domains). It will route neither of these to
           Unicast DNS servers. Also, it will do LLMNR and Multicast DNS
           only on interfaces suitable for multicast.

           On output, these five flags indicate which protocol was used
           to execute the operation, and hence where the data was found.

           The primary use cases for these five flags are follow-up
           look-ups based on DNS data retrieved earlier. In this case it
           is often a good idea to limit the follow-up look-up to the
           protocol that was used to discover the first DNS result.

           The NO_CNAME flag controls whether CNAME/DNAME resource
           records shall be followed during the look-up. This flag is
           only available at input, none of the functions will return it
           on output. If a CNAME/DNAME RR is discovered while resolving
           a hostname, an error is returned instead. By default, when
           the flag is off, CNAME/DNAME RRs are followed.

           The NO_TXT and NO_ADDRESS flags only influence operation of
           the ResolveService() method. They are only defined for input,
           not output. If NO_TXT set, the DNS-SD TXT RR look-up is not
           done in the same operation. If NO_ADDRESS is specified, the
           hostnames discovered are not implicitly translated to their
           addresses.

           The NO_SEARCH flag turns off the search domain logic. It is
           only defined for input in ResolveHostname(). When specified,
           single-label hostnames are not qualified using defined search
           domains, if any are configured. Note that ResolveRecord()
           will never qualify single-label domain names using search
           domains. Also note that multi-label hostnames are never
           subject to search list expansion.

           The AUTHENTICATED bit is defined only in the output flags of
           the four functions. If set, the returned data has been fully
           authenticated. Specifically, this bit is set for all
           DNSSEC-protected data for which a full trust chain may be
           established to a trusted domain anchor. It is also set for
           locally synthesized data, such as "localhost" or data from
           /etc/hosts. Moreover, it is set for all LLMNR or mDNS RRs
           which originate from the local host. Applications that
           require authenticated RR data for operation should check this
           flag before trusting the data. Note that systemd-resolved
           will never return invalidated data, hence this flag simply
           allows to discern the cases where data is known to be
           trustable, or where there is proof that the data is
           "rightfully" unauthenticated (which includes cases where the
           underlying protocol or server does not support authenticating
           data).

   Properties
       The LLMNR and MulticastDNS properties report whether LLMNR and
       MulticastDNS are (globally) enabled. Each may be one of "yes",
       "no", and "resolve". See SetLinkLLMNR() and SetLinkMulticastDNS()
       above.

       LLMNRHostname contains the hostname currently exposed on the
       network via LLMNR. It usually follows the system hostname as may
       be queried via gethostname(3), but may differ if a conflict is
       detected on the network.

       DNS and DNSEx contain arrays of all DNS servers currently used by
       systemd-resolved.  DNS contains information similar to the DNS
       server data in /run/systemd/resolve/resolv.conf. Each structure
       in the array consists of a numeric network interface index, an
       address family, and a byte array containing the DNS server
       address (either 4 bytes in length for IPv4 or 16 bytes in lengths
       for IPv6).  DNSEx is similar, but additionally contains the IP
       port and server name (used for Server Name Indication, SNI). Both
       arrays contain DNS servers configured system-wide, including
       those possibly read from a foreign /etc/resolv.conf or the DNS=
       setting in /etc/systemd/resolved.conf, as well as per-interface
       DNS server information either retrieved from systemd-networkd(8),
       or configured by external software via SetLinkDNS() or
       SetLinkDNSEx() (see above). The network interface index will be 0
       for the system-wide configured services and non-zero for the
       per-link servers.

       FallbackDNS and FallbackDNSEx contain arrays of all DNS servers
       configured as fallback servers, if any, using the same format as
       DNS and DNSEx described above. See the description of
       FallbackDNS= in resolved.conf(5) for the description of when
       those servers are used.

       CurrentDNSServer and CurrentDNSServerEx specify the server that
       is currently used for query resolution, in the same format as a
       single entry in the DNS and DNSEx arrays described above.

       Similarly, the Domains property contains an array of all search
       and routing domains currently used by systemd-resolved. Each
       entry consists of a network interface index (again, 0 encodes
       system-wide entries), the actual domain name, and whether the
       entry is used only for routing (true) or for both routing and
       searching (false).

       The TransactionStatistics property contains information about the
       number of transactions systemd-resolved has processed. It
       contains a pair of unsigned 64-bit counters, the first containing
       the number of currently ongoing transactions, the second the
       number of total transactions systemd-resolved is processing or
       has processed. The latter value may be reset using the
       ResetStatistics() method described above. Note that the number of
       transactions does not directly map to the number of issued
       resolver bus method calls. While simple look-ups usually require
       a single transaction only, more complex look-ups might result in
       more, for example when CNAMEs or DNSSEC are in use.

       The CacheStatistics property contains information about the
       executed cache operations so far. It exposes three 64-bit
       counters: the first being the total number of current cache
       entries (both positive and negative), the second the number of
       cache hits, and the third the number of cache misses. The latter
       counters may be reset using ResetStatistics() (see above).

       The DNSSEC property specifies current status of DNSSEC
       validation. It is one of "yes" (validation is enforced), "no" (no
       validation is done), "allow-downgrade" (validation is done if the
       current DNS server supports it). See the description of DNSSEC=
       in resolved.conf(5).

       The DNSSECStatistics property contains information about the
       DNSSEC validations executed so far. It contains four 64-bit
       counters: the number of secure, insecure, bogus, and
       indeterminate DNSSEC validations so far. The counters are
       increased for each validated RRset, and each non-existance proof.
       The secure counter is increased for each operation that
       successfully verified a signed reply, the insecure counter is
       increased for each operation that successfully verified that an
       unsigned reply is rightfully unsigned. The bogus counter is
       increased for each operation where the validation did not check
       out and the data is likely to have been tempered with. Finally
       the indeterminate counter is increased for each operation which
       did not complete because the necessary keys could not be acquired
       or the cryptographic algorithms were unknown.

       The DNSSECSupported boolean property reports whether DNSSEC is
       enabled and the selected DNS servers support it. It combines
       information about system-wide and per-link DNS settings (see
       below), and only reports true if DNSSEC is enabled and supported
       on every interface for which DNS is configured and for the
       system-wide settings if there are any. Note that systemd-resolved
       assumes DNSSEC is supported by DNS servers until it verifies that
       this is not the case. Thus, the reported value may initially be
       true, until the first transactions are executed.

       The DNSOverTLS boolean property reports whether DNS-over-TLS is
       enabled.

       The ResolvConfMode property exposes how /etc/resolv.conf is
       managed on the host. Currently, the values "uplink", "stub",
       "static" (these three correspond to the three different files
       systemd-resolved.service provides), "foreign" (the file is
       managed by admin or another service, systemd-resolved.service
       just consumes it), "missing" (/etc/resolv.conf is missing).

       The DNSStubListener property reports whether the stub listener on
       port 53 is enabled. Possible values are "yes" (enabled), "no"
       (disabled), "udp" (only the UDP listener is enabled), and "tcp"
       (only the TCP listener is enabled).

LINK OBJECT         top

           node /org/freedesktop/resolve1/link/_1 {
             interface org.freedesktop.resolve1.Link {
               methods:
                 SetDNS(in  a(iay) addresses);
                 SetDNSEx(in  a(iayqs) addresses);
                 SetDomains(in  a(sb) domains);
                 SetDefaultRoute(in  b enable);
                 SetLLMNR(in  s mode);
                 SetMulticastDNS(in  s mode);
                 SetDNSOverTLS(in  s mode);
                 SetDNSSEC(in  s mode);
                 SetDNSSECNegativeTrustAnchors(in  as names);
                 Revert();
               properties:
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly t ScopesMask = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly a(iay) DNS = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly a(iayqs) DNSEx = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly (iay) CurrentDNSServer = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly (iayqs) CurrentDNSServerEx = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly a(sb) Domains = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly b DefaultRoute = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s LLMNR = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s MulticastDNS = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s DNSOverTLS = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s DNSSEC = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly as DNSSECNegativeTrustAnchors = ['...', ...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly b DNSSECSupported = ...;
             };
             interface org.freedesktop.DBus.Peer { ... };
             interface org.freedesktop.DBus.Introspectable { ... };
             interface org.freedesktop.DBus.Properties { ... };
           };

       For each Linux network interface a "Link" object is created which
       exposes per-link DNS configuration and state. Use GetLink() on
       the Manager interface to retrieve the object path for a link
       object given the network interface index (see above).

   Methods
       The various methods exposed by the Link interface are equivalent
       to their similarly named counterparts on the Manager interface.
       e.g.  SetDNS() on the Link object maps to SetLinkDNS() on the
       Manager object, the main difference being that the later expects
       an interface index to be specified. Invoking the methods on the
       Manager interface has the benefit of reducing roundtrips, as it
       is not necessary to first request the Link object path via
       GetLink() before invoking the methods. The same relationship
       holds for SetDNSEx(), SetDomains(), SetDefaultRoute(),
       SetLLMNR(), SetMulticastDNS(), SetDNSOverTLS(), SetDNSSEC(),
       SetDNSSECNegativeTrustAnchors(), and Revert(). For further
       details on these methods see the Manager documentation above.

   Properties
       ScopesMask defines which resolver scopes are currently active on
       this interface. This 64-bit unsigned integer field is a bit mask
       consisting of a subset of the bits of the flags parameter
       describe above. Specifically, it may have the DNS, LLMNR and MDNS
       bits (the latter in IPv4 and IPv6 flavours) set. Each individual
       bit is set when the protocol applies to a specific interface and
       is enabled for it. It is unset otherwise. Specifically, a
       multicast-capable interface in the "UP" state with an IP address
       is suitable for LLMNR or MulticastDNS, and any interface that is
       UP and has an IP address is suitable for DNS. Note the
       relationship of the bits exposed here with the LLMNR and
       MulticastDNS properties also exposed on the Link interface. The
       latter expose what is *configured* to be used on the interface,
       the former expose what is actually used on the interface, taking
       into account the abilities of the interface.

       DNSSECSupported exposes a boolean field that indicates whether
       DNSSEC is currently configured and in use on the interface. Note
       that if DNSSEC is enabled on an interface, it is assumed
       available until it is detected that the configured server does
       not actually support it. Thus, this property may initially report
       that DNSSEC is supported on an interface.

       DefaultRoute exposes a boolean field that indicates whether the
       interface will be used as default route for name queries. See
       SetLinkDefaultRoute() above.

       The other properties reflect the state of the various
       configuration settings for the link which may be set with the
       various methods calls such as SetDNS() or SetLLMNR().

COMMON ERRORS         top

       Many bus methods systemd-resolved exposes (in particular the
       resolver methods such as ResolveHostname() on the Manager
       interface) may return some of the following errors:

       org.freedesktop.resolve1.NoNameServers
           No suitable DNS servers were found to resolve a request.

       org.freedesktop.resolve1.InvalidReply
           A response from the selected DNS server was not understood.

       org.freedesktop.resolve1.NoSuchRR
           The requested name exists, but there is no resource record of
           the requested type for it. (This is the DNS NODATA case).

       org.freedesktop.resolve1.CNameLoop
           The look-up failed because a CNAME or DNAME loop was
           detected.

       org.freedesktop.resolve1.Aborted
           The look-up was aborted because the selected protocol became
           unavailable while the operation was ongoing.

       org.freedesktop.resolve1.NoSuchService
           A service look-up was successful, but the SRV record reported
           that the service is not available.

       org.freedesktop.resolve1.DnssecFailed
           The acquired response did not pass DNSSEC validation.

       org.freedesktop.resolve1.NoTrustAnchor
           No chain of trust could be established for the response to a
           configured DNSSEC trust anchor.

       org.freedesktop.resolve1.ResourceRecordTypeUnsupported
           The requested resource record type is not supported on the
           selected DNS servers. This error is generated for example
           when an RRSIG record is requested from a DNS server that does
           not support DNSSEC.

       org.freedesktop.resolve1.NoSuchLink
           No network interface with the specified network interface
           index exists.

       org.freedesktop.resolve1.LinkBusy
           The requested configuration change could not be made because
           systemd-networkd(8), already took possession of the interface
           and supplied configuration data for it.

       org.freedesktop.resolve1.NetworkDown
           The requested look-up failed because the system is currently
           not connected to any suitable network.

       org.freedesktop.resolve1.DnsError.NXDOMAIN,
       org.freedesktop.resolve1.DnsError.REFUSED, ...
           The look-up failed with a DNS return code reporting a
           failure. The error names used as suffixes here are defined in
           by IANA in DNS RCODEs[4].

EXAMPLES         top

       Example 1. Introspect org.freedesktop.resolve1.Manager on the bus

           $ gdbus introspect --system \
             --dest org.freedesktop.resolve1 \
             --object-path /org/freedesktop/resolve1

       Example 2. Introspect org.freedesktop.resolve1.Link on the bus

           $ gdbus introspect --system \
             --dest org.freedesktop.resolve1 \
             --object-path /org/freedesktop/resolve1/link/_11

VERSIONING         top

       These D-Bus interfaces follow the usual interface versioning
       guidelines[5].

NOTES         top

        1. Writing Network Configuration Managers
           https://wiki.freedesktop.org/www/Software/systemd/writing-network-configuration-managers

        2. Writing Resolver Clients
           https://wiki.freedesktop.org/www/Software/systemd/writing-resolver-clients

        3. RFC 1035
           https://www.ietf.org/rfc/rfc1035.txt

        4. DNS RCODEs
           https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6

        5. the usual interface versioning guidelines
           http://0pointer.de/blog/projects/versioning-dbus.html

COLOPHON         top

       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 2021-08-27.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-08-27.)  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 249                                  ORG.FREEDESKTOP.RESOLVE1(5)

Pages that refer to this page: systemd-resolved.service(8)