NAME

       timesyncd.conf, timesyncd.conf.d - Network Time Synchronization configuration files

SYNOPSIS

       /etc/systemd/timesyncd.conf

       /etc/systemd/timesyncd.conf.d/*.conf

       /run/systemd/timesyncd.conf.d/*.conf

       /usr/lib/systemd/timesyncd.conf.d/*.conf

DESCRIPTION

       These configuration files control NTP network time synchronization. See systemd.syntax(7) for a general
       description of the syntax.

CONFIGURATION DIRECTORIES AND PRECEDENCE

       The default configuration is set during compilation, so configuration is only needed when it is necessary
       to deviate from those defaults. Initially, the main configuration file in /etc/systemd/ contains
       commented out entries showing the defaults as a guide to the administrator. Local overrides can be
       created by editing this file or by creating drop-ins, as described below. Using drop-ins for local
       configuration is recommended over modifications to the main configuration file.

       In addition to the "main" configuration file, drop-in configuration snippets are read from
       /usr/lib/systemd/*.conf.d/, /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/. Those drop-ins
       have higher precedence and override the main configuration file. Files in the *.conf.d/ configuration
       subdirectories are sorted by their filename in lexicographic order, regardless of in which of the
       subdirectories they reside. When multiple files specify the same option, for options which accept just a
       single value, the entry in the file sorted last takes precedence, and for options which accept a list of
       values, entries are collected as they occur in the sorted files.

       When packages need to customize the configuration, they can install drop-ins under /usr/. Files in /etc/
       are reserved for the local administrator, who may use this logic to override the configuration files
       installed by vendor packages. Drop-ins have to be used to override package drop-ins, since the main
       configuration file has lower precedence. It is recommended to prefix all filenames in those
       subdirectories with a two-digit number and a dash, to simplify the ordering of the files.

       To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to
       /dev/null in the configuration directory in /etc/, with the same filename as the vendor configuration
       file.

OPTIONS

       The following settings are configured in the [Time] section:

       NTP=
           A space-separated list of NTP server host names or IP addresses. During runtime this list is combined
           with any per-interface NTP servers acquired from systemd-networkd.service(8).  systemd-timesyncd will
           contact all configured system or per-interface servers in turn, until one responds. When the empty
           string is assigned, the list of NTP servers is reset, and all prior assignments will have no effect.
           This setting defaults to an empty list.

       FallbackNTP=
           A space-separated list of NTP server host names or IP addresses to be used as the fallback NTP
           servers. Any per-interface NTP servers obtained from systemd-networkd.service(8) take precedence over
           this setting, as do any servers set via NTP= above. This setting is hence only relevant if no other
           NTP server information is known. When the empty string is assigned, the list of NTP servers is reset,
           and all prior assignments will have no effect. If this option is not given, a compiled-in list of NTP
           servers is used.

       RootDistanceMaxSec=
           Maximum acceptable root distance, i.e. the maximum estimated time required for a packet to travel to
           the server we are connected to from the server with the reference clock. If the current server does
           not satisfy this limit, systemd-timesyncd will switch to a different server.

           Takes a time span value. The default unit is seconds, but other units may be specified, see
           systemd.time(5). Defaults to 5 seconds.

       PollIntervalMinSec=, PollIntervalMaxSec=
           The minimum and maximum poll intervals for NTP messages. Polling starts at the minimum poll interval,
           and is adjusted within the specified limits in response to received packets.

           Each setting takes a time span value. The default unit is seconds, but other units may be specified,
           see systemd.time(5).  PollIntervalMinSec= defaults to 32 seconds and must not be smaller than
           16 seconds.  PollIntervalMaxSec= defaults to 34 min 8 s (2048 seconds) and must be larger than
           PollIntervalMinSec=.

       ConnectionRetrySec=
           Specifies the minimum delay before subsequent attempts to contact a new NTP server are made.

           Takes a time span value. The default unit is seconds, but other units may be specified, see
           systemd.time(5). Defaults to 30 seconds and must not be smaller than 1 second.

SEE ALSO

       systemd(1), systemd-timesyncd.service(8), systemd-networkd.service(8)