man/timesyncd.conf.xml

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  10   Copyright 2014 Lennart Poettering
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  25
  26 <refentry id="timesyncd.conf" conditional='ENABLE_TIMESYNCD'
  27     xmlns:xi="http://www.w3.org/2001/XInclude">
  28   <refentryinfo>
  29     <title>timesyncd.conf</title>
  30     <productname>systemd</productname>
  31
  32     <authorgroup>
  33       <author>
  34         <contrib>Developer</contrib>
  35         <firstname>Lennart</firstname>
  36         <surname>Poettering</surname>
  37         <email>lennart@poettering.net</email>
  38       </author>
  39     </authorgroup>
  40   </refentryinfo>
  41
  42   <refmeta>
  43     <refentrytitle>timesyncd.conf</refentrytitle>
  44     <manvolnum>5</manvolnum>
  45   </refmeta>
  46
  47   <refnamediv>
  48     <refname>timesyncd.conf</refname>
  49     <refname>timesyncd.conf.d</refname>
  50     <refpurpose>Network Time Synchronization configuration files</refpurpose>
  51   </refnamediv>
  52
  53   <refsynopsisdiv>
  54     <para><filename>/etc/systemd/timesyncd.conf</filename></para>
  55     <para><filename>/etc/systemd/timesyncd.conf.d/*.conf</filename></para>
  56     <para><filename>/run/systemd/timesyncd.conf.d/*.conf</filename></para>
  57     <para><filename>/usr/lib/systemd/timesyncd.conf.d/*.conf</filename></para>
  58   </refsynopsisdiv>
  59
  60   <refsect1>
  61     <title>Description</title>
  62
  63     <para>These configuration files control NTP network time
  64     synchronization.</para>
  65
  66   </refsect1>
  67
  68   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  69
  70   <refsect1>
  71     <title>Options</title>
  72
  73     <para>The following settings are configured in the <literal>[Time]</literal> section:</para>
  74
  75     <variablelist class='network-directives'>
  76
  77       <varlistentry>
  78         <term><varname>NTP=</varname></term>
  79         <listitem><para>A space-separated list of NTP server host
  80         names or IP addresses. During runtime this list is combined
  81         with any per-interface NTP servers acquired from
  82         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  83         systemd-timesyncd will contact all configured system or
  84         per-interface servers in turn until one is found that
  85         responds. When the empty string is assigned, the list of
  86         NTP servers is reset, and all assignments prior to this one
  87         will have no effect. This setting defaults to an empty
  88         list.</para></listitem>
  89       </varlistentry>
  90
  91       <varlistentry>
  92         <term><varname>FallbackNTP=</varname></term>
  93         <listitem><para>A space-separated list of NTP server host
  94         names or IP addresses to be used as the fallback NTP servers.
  95         Any per-interface NTP servers obtained from
  96         <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  97         take precedence over this setting, as do any servers set via
  98         <varname>NTP=</varname> above. This setting is hence only used
  99         if no other NTP server information is known. When the empty
 100         string is assigned, the list of NTP servers is reset,
 101         and all assignments prior to this one will have no effect.
 102         If this option is not given, a compiled-in list of NTP servers
 103         is used instead.</para></listitem>
 104       </varlistentry>
 105
 106       <varlistentry>
 107         <term><varname>RootDistanceMaxSec=</varname></term>
 108         <listitem><para>Maximum acceptable root distance. Takes a time value (in seconds).
 109         Defaults to 5 seconds.</para></listitem>
 110       </varlistentry>
 111
 112       <varlistentry>
 113         <term><varname>PollIntervalMinSec=</varname></term>
 114         <term><varname>PollIntervalMaxSec=</varname></term>
 115         <listitem><para>The minimum and maximum poll intervals for NTP messages.
 116         Each setting takes a time value (in seconds).
 117         <varname>PollIntervalMinSec=</varname> must not be smaller than 16 seconds.
 118         <varname>PollIntervalMaxSec=</varname> must be larger than <varname>PollIntervalMinSec=</varname>.
 119         <varname>PollIntervalMinSec=</varname> defaults to 32 seconds, and
 120         <varname>PollIntervalMaxSec=</varname> defaults to 2048 seconds.</para></listitem>
 121       </varlistentry>
 122
 123     </variablelist>
 124   </refsect1>
 125
 126   <refsect1>
 127       <title>See Also</title>
 128       <para>
 129       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 130       <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 131       <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 132       </para>
 133   </refsect1>
 134
 135 </refentry>