| <?xml version="1.0"?> |
| <!--*-nxml-*--> |
| <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
| "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ |
| <!ENTITY % entities SYSTEM "custom-entities.ent" > |
| %entities; |
| ]> |
| <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
| |
| <refentry id="org.freedesktop.resolve1" conditional='ENABLE_RESOLVE' |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| <refentryinfo> |
| <title>org.freedesktop.resolve1</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>org.freedesktop.resolve1</refentrytitle> |
| <manvolnum>5</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>org.freedesktop.resolve1</refname> |
| <refpurpose>The D-Bus interface of systemd-resolved</refpurpose> |
| </refnamediv> |
| |
| <refsect1> |
| <title>Introduction</title> |
| |
| <para> |
| <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| 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.</para> |
| |
| <para>This page contains an API reference only. If you are looking for a longer explanation how to use |
| this API, please consult |
| <ulink url="https://wiki.freedesktop.org/www/Software/systemd/writing-network-configuration-managers"> |
| Writing Network Configuration Managers</ulink> and |
| <ulink url="https://wiki.freedesktop.org/www/Software/systemd/writing-resolver-clients">Writing Resolver |
| Clients</ulink>. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>The Manager Object</title> |
| |
| <para>The service exposes the following interfaces on the Manager object on the bus:</para> |
| |
| <programlisting executable="systemd-resolved" node="/org/freedesktop/resolve1" interface="org.freedesktop.resolve1.Manager"> |
| 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 { ... }; |
| }; |
| </programlisting> |
| |
| <!--method RegisterService is not documented!--> |
| |
| <!--method UnregisterService is not documented!--> |
| |
| <!--method FlushCaches is not documented!--> |
| |
| <!--method ResetServerFeatures is not documented!--> |
| |
| <!--property DNSSECNegativeTrustAnchors is not documented!--> |
| |
| <!--Autogenerated cross-references for systemd.directives, do not edit--> |
| |
| <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Manager"/> |
| |
| <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Manager"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="ResolveHostname()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="ResolveAddress()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="ResolveRecord()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="ResolveService()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="GetLink()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNS()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSEx()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDomains()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDefaultRoute()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkLLMNR()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkMulticastDNS()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSOverTLS()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSSEC()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLinkDNSSECNegativeTrustAnchors()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="RevertLink()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="RegisterService()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="UnregisterService()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="ResetStatistics()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="FlushCaches()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="ResetServerFeatures()"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="LLMNRHostname"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="LLMNR"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="MulticastDNS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSOverTLS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSEx"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="FallbackDNS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="FallbackDNSEx"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServer"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServerEx"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="Domains"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="TransactionStatistics"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="CacheStatistics"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSEC"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSECStatistics"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSECSupported"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSECNegativeTrustAnchors"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSStubListener"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="ResolvConfMode"/> |
| |
| <!--End of Autogenerated section--> |
| |
| <refsect2> |
| <title>Methods</title> |
| |
| <para><function>ResolveHostname()</function> 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 <varname>name</varname> 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 <varname>family</varname> parameter limits the results to a specific address |
| family. It may be <constant>AF_INET</constant>, <constant>AF_INET6</constant> or |
| <constant>AF_UNSPEC</constant>. If <constant>AF_UNSPEC</constant> 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 <varname>flags</varname> 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 |
| <constant>AF_INET</constant> or <constant>AF_INET6</constant>. For IPv6, the returned address interface |
| index should be used to initialize the .sin6_scope_id field of a |
| <structname>struct sockaddr_in6</structname> 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 <varname>flags</varname> field is returned that |
| is defined similarly to the <varname>flags</varname> 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.</para> |
| |
| <para><function>ResolveAddress()</function> 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 <constant>0</constant> if all suitable interfaces are OK. The <varname>family</varname> |
| parameter indicates the address family of the IP address to resolve. It may be either |
| <constant>AF_INET</constant> or <constant>AF_INET6</constant>. The <varname>address</varname> parameter |
| takes the raw IP address data (as either a 4 or 16 byte array). The <varname>flags</varname> 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 <varname>flags</varname> output |
| field contains additional information about the resolver operation (see below).</para> |
| |
| <para><function>ResolveRecord()</function> 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 <constant>0</constant> if it may be done on |
| any suitable interface. The <varname>name</varname> 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 <varname>flags</varname> 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 |
| <ulink url="https://www.ietf.org/rfc/rfc1035.txt">RFC 1035</ulink>. For RRs that support name |
| compression in the payload (such as MX or PTR), the compression is expanded in the returned |
| data.</para> |
| |
| <para>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 <filename>systemd-resolved</filename> 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.</para> |
| |
| <para><function>ResolveService()</function> may be used to resolve a DNS |
| <constant class="dns">SRV</constant> service record, as well as the hostnames referenced in it, and |
| possibly an accompanying DNS-SD <constant class="dns">TXT</constant> record containing additional |
| service metadata. The primary benefit of using this method over <function>ResolveRecord()</function> |
| specifying the <constant class="dns">SRV</constant> type is that it will resolve the |
| <constant class="dns">SRV</constant> and <constant class="dns">TXT</constant> 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:</para> |
| |
| <orderedlist> |
| <listitem><para>To resolve a DNS-SD service, specify the service name (e.g. <literal>Lennart's |
| Files</literal>), the service type (e.g. <literal>_webdav._tcp</literal>) and the domain to search in |
| (e.g. <literal>local</literal>) 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.</para> |
| </listitem> |
| |
| <listitem><para>To resolve a plain <constant class="dns">SRV</constant> 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.)</para></listitem> |
| |
| <listitem><para>Alternatively, leave both the service name and type empty and specify the full domain |
| name of the <constant class="dns">SRV</constant> record (i.e. prefixed with the service type) in the |
| domain parameter. (No IDNA conversion is applied in this mode.)</para></listitem> |
| </orderedlist> |
| |
| <para>The <varname>family</varname> parameter of the <function>ResolveService()</function> method encodes |
| the desired family of the addresses to resolve (use <constant>AF_INET</constant>, |
| <constant>AF_INET6</constant>, or <constant>AF_UNSPEC</constant>). If this is enabled (Use the |
| <constant>NO_ADDRESS</constant> flag to turn address resolution off, see below). The |
| <varname>flags</varname> parameter takes a couple of flags that may be used to alter the resolver |
| operation.</para> |
| |
| <para>On completion, <function>ResolveService()</function> returns an array of |
| <constant class="dns">SRV</constant> record structures. Each items consisting of the priority, weight and port |
| fields as well as the hostname to contact, as encoded in the <constant class="dns">SRV</constant> |
| 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 <constant class="dns">SRV</constant> 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 <varname>flags</varname> field is returned that |
| contains information about the resolver operation performed.</para> |
| |
| <para>The <function>ResetStatistics()</function> method resets the various statistics counters that |
| <filename>systemd-resolved</filename> maintains to zero. (For details, see the statistics properties below.)</para> |
| |
| <para>The <function>GetLink()</function> method takes a network interface index and returns the object |
| path to the <interfacename>org.freedesktop.resolve1.Link</interfacename> object corresponding to it. |
| </para> |
| |
| <para>The <function>SetLinkDNS()</function> 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 <constant>AF_INET</constant> or |
| <constant>AF_INET6</constant>), 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 |
| <function>GetLink()</function> (see above) and then invoking the <function>SetDNS()</function> method |
| (see below) on it.</para> |
| |
| <para><function>SetLinkDNSEx()</function> is similar to <function>SetLinkDNS()</function>, 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. <varname>DNS=</varname> in |
| <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
| </para> |
| |
| <para><function>SetLinkDefaultRoute()</function> specifies whether the link shall be used as the |
| default route for name queries. See the description of name routing in |
| <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for details.</para> |
| |
| <para>The <function>SetLinkDomains()</function> 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.</para> |
| |
| <para>The <function>SetLinkLLMNR()</function> 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 |
| <literal>yes</literal>, <literal>no</literal> or <literal>resolve</literal>. If empty, the systemd-wide |
| default LLMNR setting is used. If <literal>yes</literal>, 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 |
| <literal>no</literal>, LLMNR is turned off fully on this interface. If <literal>resolve</literal>, LLMNR |
| is only enabled for resolving names, but the local hostname is not registered for other peers to |
| use.</para> |
| |
| <para>Similarly, the <function>SetLinkMulticastDNS()</function> method enables or disables MulticastDNS |
| support on a specific interface. It takes the same parameters as <function>SetLinkLLMNR()</function> |
| described above.</para> |
| |
| <para>The <function>SetLinkDNSSEC()</function> 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 <literal>yes</literal>, <literal>no</literal>, or <literal>allow-downgrade</literal>. When |
| empty, the system-wide default DNSSEC setting is used. If <literal>yes</literal>, 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 <literal>no</literal>, DNSSEC validation is fully disabled. If |
| <literal>allow-downgrade</literal>, 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.</para> |
| |
| <para>The <function>SetLinkDNSSECNegativeTrustAnchors()</function> 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.</para> |
| |
| <para>The <function>SetLinkDNSOverTLS()</function> method enables or disables DNS-over-TLS. |
| C.f. <varname>DNSOverTLS=</varname> in |
| <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for details.</para> |
| |
| <para>Network management software integrating with <filename>systemd-resolved</filename> should call |
| <function>SetLinkDNS()</function> or <function>SetLinkDNSEx()</function>, |
| <function>SetLinkDefaultRoute()</function>, <function>SetLinkDomains()</function> 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 (<constant>IFF_UP</constant> 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 <function>RevertLink()</function> (described below) to reset all |
| per-interface settings.</para> |
| |
| <para>The <function>RevertLink()</function> method may be used to revert all per-link settings |
| described above to the defaults.</para> |
| |
| <refsect3> |
| <title>The Flags Parameter</title> |
| |
| <para>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:</para> |
| |
| <programlisting> |
| #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) |
| #define SD_RESOLVED_NO_VALIDATE (UINT64_C(1) << 10) |
| #define SD_RESOLVED_NO_SYNTHESIZE (UINT64_C(1) << 11) |
| #define SD_RESOLVED_NO_CACHE (UINT64_C(1) << 12) |
| #define SD_RESOLVED_NO_ZONE (UINT64_C(1) << 13) |
| #define SD_RESOLVED_NO_TRUST_ANCHOR (UINT64_C(1) << 14) |
| #define SD_RESOLVED_NO_NETWORK (UINT64_C(1) << 15) |
| #define SD_RESOLVED_REQUIRE_PRIMARY (UINT64_C(1) << 16) |
| #define SD_RESOLVED_CLAMP_TTL (UINT64_C(1) << 17) |
| #define SD_RESOLVED_CONFIDENTIAL (UINT64_C(1) << 18) |
| #define SD_RESOLVED_SYNTHETIC (UINT64_C(1) << 19) |
| #define SD_RESOLVED_FROM_CACHE (UINT64_C(1) << 20) |
| #define SD_RESOLVED_FROM_ZONE (UINT64_C(1) << 21) |
| #define SD_RESOLVED_FROM_TRUST_ANCHOR (UINT64_C(1) << 22) |
| #define SD_RESOLVED_FROM_NETWORK (UINT64_C(1) << 23) |
| </programlisting> |
| |
| <para>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, |
| <filename>systemd-resolved</filename> 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.</para> |
| |
| <para>On output, these five flags indicate which protocol was used to execute the operation, and hence |
| where the data was found.</para> |
| |
| <para>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.</para> |
| |
| <para>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.</para> |
| |
| <para>The NO_TXT and NO_ADDRESS flags only influence operation of the |
| <function>ResolveService()</function> method. They are only defined for input, not output. If NO_TXT |
| is set, the DNS-SD TXT RR look-up is not done in the same operation. If NO_ADDRESS is set, the |
| discovered hostnames are not implicitly translated to their addresses.</para> |
| |
| <para>The NO_SEARCH flag turns off the search domain logic. It is only defined for input in |
| <function>ResolveHostname()</function>. When specified, single-label hostnames are not qualified |
| using defined search domains, if any are configured. Note that <function>ResolveRecord()</function> |
| will never qualify single-label domain names using search domains. Also note that |
| multi-label hostnames are never subject to search list expansion.</para> |
| |
| <para>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 <literal>localhost</literal> or data from |
| <filename>/etc/hosts</filename>. 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 <filename>systemd-resolved</filename> will never return |
| invalidated data, hence this flag simply allows one to discern the cases where data is known to be |
| trusted, 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).</para> |
| |
| <para>NO_VALIDATE can be set to disable validation via DNSSEC even if it would normally be used. |
| </para> |
| |
| <para>The next four flags allow disabling certain sources during resolution. NO_SYNTHESIZE disables |
| synthetic records, e.g. the local host name, see section SYNTHETIC RECORDS in |
| <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for more information. NO_CACHE disables the use of the cache of previously resolved records. NO_ZONE |
| disables answers using locally registered public LLMNR/mDNS resource records. NO_TRUST_ANCHOR |
| disables answers using locally configured trust anchors. NO_NETWORK requires all answers to be |
| provided without using the network, i.e. either from local sources or the cache.</para> |
| |
| <para>With REQUIRE_PRIMARY the request must be answered from a "primary" answer, i.e. not from |
| resource records acquired as a side-effect of a previous transaction.</para> |
| |
| <para>With CLAMP_TTL, if reply is answered from cache, the TTLs will be adjusted by age of cache |
| entry.</para> |
| |
| <para>The next six bits flags are used in output and provide information about the source of the answer. |
| CONFIDENTIAL means the query was resolved via encrypted channels or never left this system. |
| FROM_SYNTHETIC means the query was (at least partially) synthesized. |
| FROM_CACHE means the query was answered (at least partially) using the cache. |
| FROM_ZONE means the query was answered (at least partially) using LLMNR/mDNS. |
| FROM_TRUST_ANCHOR means the query was answered (at least partially) using local trust anchors. |
| FROM_NETWORK means the query was answered (at least partially) using the network. |
| </para> |
| </refsect3> |
| </refsect2> |
| |
| <refsect2> |
| <title>Properties</title> |
| |
| <para>The <varname>LLMNR</varname> and <varname>MulticastDNS</varname> properties report whether LLMNR |
| and MulticastDNS are (globally) enabled. Each may be one of <literal>yes</literal>, |
| <literal>no</literal>, and <literal>resolve</literal>. See <function>SetLinkLLMNR()</function> |
| and <function>SetLinkMulticastDNS()</function> above.</para> |
| |
| <para><varname>LLMNRHostname</varname> contains the hostname currently exposed on the network via |
| LLMNR. It usually follows the system hostname as may be queried via |
| <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| but may differ if a conflict is detected on the network.</para> |
| |
| <para><varname>DNS</varname> and <varname>DNSEx</varname> contain arrays of all DNS servers currently |
| used by <filename>systemd-resolved</filename>. <varname>DNS</varname> contains information similar to |
| the DNS server data in <filename>/run/systemd/resolve/resolv.conf</filename>. 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). |
| <varname>DNSEx</varname> 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 <filename>/etc/resolv.conf</filename> or the <varname>DNS=</varname> |
| setting in <filename>/etc/systemd/resolved.conf</filename>, as well as per-interface DNS server |
| information either retrieved from |
| <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| or configured by external software via <function>SetLinkDNS()</function> or |
| <function>SetLinkDNSEx()</function> (see above). The network interface index will be 0 for the |
| system-wide configured services and non-zero for the per-link servers.</para> |
| |
| <para><varname>FallbackDNS</varname> and <varname>FallbackDNSEx</varname> contain arrays of all DNS |
| servers configured as fallback servers, if any, using the same format as <varname>DNS</varname> and |
| <varname>DNSEx</varname> described above. See the description of <varname>FallbackDNS=</varname> in |
| <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for |
| the description of when those servers are used.</para> |
| |
| <para><varname>CurrentDNSServer</varname> and <varname>CurrentDNSServerEx</varname> specify the server |
| that is currently used for query resolution, in the same format as a single entry in the |
| <varname>DNS</varname> and <varname>DNSEx</varname> arrays described above.</para> |
| |
| <para>Similarly, the <varname>Domains</varname> property contains an array of all search and routing |
| domains currently used by <filename>systemd-resolved</filename>. 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).</para> |
| |
| <para>The <varname>TransactionStatistics</varname> property contains information about the number of |
| transactions <filename>systemd-resolved</filename> 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 |
| <filename>systemd-resolved</filename> is processing or has processed. The latter value may be reset using the |
| <function>ResetStatistics()</function> 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.</para> |
| |
| <para>The <varname>CacheStatistics</varname> 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 <function>ResetStatistics()</function> (see |
| above).</para> |
| |
| <para>The <varname>DNSSEC</varname> property specifies current status of DNSSEC validation. It is one |
| of <literal>yes</literal> (validation is enforced), <literal>no</literal> (no validation is done), |
| <literal>allow-downgrade</literal> (validation is done if the current DNS server supports it). See the |
| description of <varname>DNSSEC=</varname> in |
| <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. |
| </para> |
| |
| <para>The <varname>DNSSECStatistics</varname> 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-existence 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.</para> |
| |
| <para>The <varname>DNSSECSupported</varname> 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 <filename>systemd-resolved</filename> 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.</para> |
| |
| <para>The <varname>DNSOverTLS</varname> boolean property reports whether DNS-over-TLS is enabled. |
| </para> |
| |
| <para>The <varname>ResolvConfMode</varname> property exposes how <filename>/etc/resolv.conf</filename> |
| is managed on the host. Currently, the values <literal>uplink</literal>, <literal>stub</literal>, |
| <literal>static</literal> (these three correspond to the three different files |
| <filename>systemd-resolved.service</filename> provides), <literal>foreign</literal> (the file is |
| managed by admin or another service, <filename>systemd-resolved.service</filename> just consumes it), |
| <literal>missing</literal> (<filename>/etc/resolv.conf</filename> is missing).</para> |
| |
| <para>The <varname>DNSStubListener</varname> property reports whether the stub listener on port 53 is |
| enabled. Possible values are <literal>yes</literal> (enabled), <literal>no</literal> (disabled), |
| <literal>udp</literal> (only the UDP listener is enabled), and <literal>tcp</literal> (only the TCP |
| listener is enabled).</para> |
| </refsect2> |
| </refsect1> |
| |
| <refsect1> |
| <title>Link Object</title> |
| |
| <programlisting executable="systemd-resolved" node="/org/freedesktop/resolve1/link/_1" interface="org.freedesktop.resolve1.Link"> |
| 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 { ... }; |
| }; |
| </programlisting> |
| |
| <!--property DNSSECNegativeTrustAnchors is not documented!--> |
| |
| <!--Autogenerated cross-references for systemd.directives, do not edit--> |
| |
| <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Link"/> |
| |
| <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.resolve1.Link"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDNS()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDNSEx()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDomains()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDefaultRoute()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetLLMNR()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetMulticastDNS()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDNSOverTLS()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDNSSEC()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="SetDNSSECNegativeTrustAnchors()"/> |
| |
| <variablelist class="dbus-method" generated="True" extra-ref="Revert()"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="ScopesMask"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSEx"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServer"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="CurrentDNSServerEx"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="Domains"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DefaultRoute"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="LLMNR"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="MulticastDNS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSOverTLS"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSEC"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSECNegativeTrustAnchors"/> |
| |
| <variablelist class="dbus-property" generated="True" extra-ref="DNSSECSupported"/> |
| |
| <!--End of Autogenerated section--> |
| |
| <para>For each Linux network interface a "Link" object is created which exposes per-link DNS |
| configuration and state. Use <function>GetLink()</function> on the Manager interface to retrieve the |
| object path for a link object given the network interface index (see above).</para> |
| |
| <refsect2> |
| <title>Methods</title> |
| |
| <para>The various methods exposed by the Link interface are equivalent to their similarly named |
| counterparts on the Manager interface. e.g. <function>SetDNS()</function> on the Link object maps to |
| <function>SetLinkDNS()</function> 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 |
| <function>GetLink()</function> before invoking the methods. The same relationship holds for |
| <function>SetDNSEx()</function>, <function>SetDomains()</function>, |
| <function>SetDefaultRoute()</function>, <function>SetLLMNR()</function>, |
| <function>SetMulticastDNS()</function>, <function>SetDNSOverTLS()</function>, |
| <function>SetDNSSEC()</function>, <function>SetDNSSECNegativeTrustAnchors()</function>, and |
| <function>Revert()</function>. For further details on these methods see the |
| <interfacename>Manager</interfacename> documentation above.</para> |
| </refsect2> |
| |
| <refsect2> |
| <title>Properties</title> |
| |
| <para><varname>ScopesMask</varname> 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.</para> |
| |
| <para><varname>DNSSECSupported</varname> 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.</para> |
| |
| <para><varname>DefaultRoute</varname> exposes a boolean field that indicates whether the interface will |
| be used as default route for name queries. See <function>SetLinkDefaultRoute()</function> above.</para> |
| |
| <para>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 <function>SetDNS()</function> or |
| <function>SetLLMNR()</function>.</para> |
| </refsect2> |
| </refsect1> |
| |
| <refsect1> |
| <title>Common Errors</title> |
| |
| <para>Many bus methods <filename>systemd-resolved</filename> exposes (in particular the resolver methods such |
| as <function>ResolveHostname()</function> on the <interfacename>Manager</interfacename> interface) may return |
| some of the following errors:</para> |
| |
| <variablelist> |
| <varlistentry><term><constant>org.freedesktop.resolve1.NoNameServers</constant></term> |
| <listitem><para>No suitable DNS servers were found to resolve a request.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.InvalidReply</constant></term> |
| <listitem><para>A response from the selected DNS server was not understood.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.NoSuchRR</constant></term> |
| <listitem><para>The requested name exists, but there is no resource record of the requested type for |
| it. (This is the DNS NODATA case).</para></listitem></varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.CNameLoop</constant></term> |
| <listitem><para>The look-up failed because a CNAME or DNAME loop was detected.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.Aborted</constant></term> |
| <listitem><para>The look-up was aborted because the selected protocol became unavailable while the |
| operation was ongoing.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.NoSuchService</constant></term> |
| <listitem><para>A service look-up was successful, but the <constant class="dns">SRV</constant> record |
| reported that the service is not available.</para></listitem></varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.DnssecFailed</constant></term> |
| <listitem><para>The acquired response did not pass DNSSEC validation.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.NoTrustAnchor</constant></term> |
| <listitem><para>No chain of trust could be established for the response to a configured DNSSEC trust |
| anchor.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.ResourceRecordTypeUnsupported</constant></term> |
| <listitem><para>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.</para></listitem> |
| |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.NoSuchLink</constant></term> |
| <listitem><para>No network interface with the specified network interface index exists. |
| </para></listitem></varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.LinkBusy</constant></term> |
| <listitem><para>The requested configuration change could not be made because |
| <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
| already took possession of the interface and supplied configuration data for it.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.NetworkDown</constant></term> |
| <listitem><para>The requested look-up failed because the system is currently not connected to any |
| suitable network.</para></listitem></varlistentry> |
| |
| <varlistentry><term><constant>org.freedesktop.resolve1.DnsError.NXDOMAIN</constant></term> |
| <term><constant>org.freedesktop.resolve1.DnsError.REFUSED</constant></term> |
| <term>...</term> |
| <listitem><para>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 |
| <ulink url="https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-6">DNS RCODEs</ulink>. |
| </para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Examples</title> |
| |
| <example> |
| <title>Introspect <interfacename>org.freedesktop.resolve1.Manager</interfacename> on the bus</title> |
| |
| <programlisting> |
| $ gdbus introspect --system \ |
| --dest org.freedesktop.resolve1 \ |
| --object-path /org/freedesktop/resolve1 |
| </programlisting> |
| </example> |
| |
| <example> |
| <title>Introspect <interfacename>org.freedesktop.resolve1.Link</interfacename> on the bus</title> |
| |
| <programlisting> |
| $ gdbus introspect --system \ |
| --dest org.freedesktop.resolve1 \ |
| --object-path /org/freedesktop/resolve1/link/_11 |
| </programlisting> |
| </example> |
| </refsect1> |
| |
| <xi:include href="org.freedesktop.locale1.xml" xpointer="versioning"/> |
| </refentry> |
