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

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

ORG.FREEDESKTOP.RESOLVE1(5)rg.freedesktop.resolve1RG.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);
                 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 = [...];
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
                 readonly a(iiay) FallbackDNS = [...];
                 readonly (iiay) CurrentDNSServer = ...;
                 @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 = '...';
             };
             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
           coversion 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.

       Network management software integrating with systemd-resolved should
       call this method (and the five below) 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 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 RevertLink() method may be used to revert all per-link settings
       done with the six methods described above to the defaults again.

       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
       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 contains an array of all DNS servers currently used by
       systemd-resolved. It contains similar information as the DNS server
       data written to /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). The array
       contains 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() (see above). The network
       interface index will be 0 for the system-wide configured services and
       non-zero for the per-link servers.

       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 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 LogLevel property shows the (maximum) log level of the manager,
       with the same values as the --log-level= option described in
       systemd(1).

LINK OBJECT         top

           node /org/freedesktop/resolve1/link/_1 {
             interface org.freedesktop.resolve1.Link {
               methods:
                 SetDNS(in  a(iay) 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 (iay) CurrentDNSServer = ...;
                 @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. 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.

       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 2020-06-09.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-06-09.)  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 245                                      ORG.FREEDESKTOP.RESOLVE1(5)

Pages that refer to this page: 30-systemd-environment-d-generator(7)systemd.directives(7)systemd.index(7)systemd-resolved(8)systemd-resolved.service(8)