niceSOFT/systemd: The systemd System and Service Manager

man/systemd.rr.xml
95 строк4 KB
Lennart Poettering
resolved: add ability to define additional local RRs via drop-ins
24 мар 2026, 23:24
24 мар 2026, 23:240718a21
<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->

<refentry id="systemd.rr"
          xmlns:xi="http://www.w3.org/2001/XInclude"
          conditional='ENABLE_RESOLVE'>

  <refentryinfo>
    <title>systemd.rr</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd.rr</refentrytitle>
    <manvolnum>5</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd.rr</refname>
    <refpurpose>Local static DNS resource record definitions</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><simplelist>
      <member><filename>/etc/systemd/resolve/static.d/*.rr</filename></member>
      <member><filename>/run/systemd/resolve/static.d/*.rr</filename></member>
      <member><filename>/usr/local/lib/systemd/resolve/static.d/*.rr</filename></member>
      <member><filename>/usr/lib/systemd/resolve/static.d/*.rr</filename></member>
    </simplelist></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><filename>*.rr</filename> files may be used to define resource record sets ("RRsets") that shall be
    resolvable locally, similar in style to address records defined by <filename>/etc/hosts</filename> (see
    <citerefentry><refentrytitle>hosts</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
    details). These files are read by
    <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
    and are used to synthesize local responses to local queries matching the defined resource record set.</para>

    <para>These drop-in files are in JSON format. Each file may either contain a single top-level DNS RR
    object, or an array of one or more DNS RR objects. Each RR object has at least a <literal>key</literal>
    subobject consisting of a <literal>name</literal> string field and a <literal>type</literal> integer
    field (which contains the RR type in numeric form). Depending on the chosen type the RR object also has
    the following fields:</para>

    <itemizedlist>
      <listitem><para>For A/AAAA RRs, the RR object should have an <literal>address</literal> field set to
      either an IP address formatted as string, or an array consisting of 4 or 16 8-bit unsigned integers for
      the IP address.</para></listitem>

      <listitem><para>For PTR/NS/CNAME/DNAME RRs, the RR object should have a <literal>name</literal> field
      set to the name the record shall point to.</para></listitem>
    </itemizedlist>

    <para>This JSON serialization of DNS RRs matches the one returned by <command>resolvectl</command>.</para>

    <para>Currently no other RR types are supported.</para>
  </refsect1>

  <refsect1>
    <title>Examples</title>
    <example>
      <title>Simple A Record</title>
      <para>To make local address lookups for <literal>foobar.example.com</literal> resolve to the
      192.168.100.1 IPv4 address, create
      <filename>/run/systemd/resolve/static.d/foobar_example_com.rr</filename>:

      <programlisting>
{
        "key" : {
                "type" : 1,
                "name" : "foobar.example.com"
        },
        "address" : [ 192, 168, 100, 1 ]
}</programlisting></para>

    </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para><simplelist type="inline">
      <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>hosts</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>resolvectl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
    </simplelist></para>
  </refsect1>

</refentry>