NAME

       ntpd.conf - Network Time Protocol daemon configuration file

DESCRIPTION

       This manual page describes the format of the ntpd(8) configuration file.

       The  optional  weight  keyword  permits finer control over the relative importance of time
       sources (servers or sensor devices).  Weights are specified in the range 1 to  10;  if  no
       weight  is  given,  the default is 1.  A server with a weight of 5, for example, will have
       five times more influence on time offset calculation than a server with a weight of 1.

       ntpd.conf has the following format:

       Empty lines and lines beginning with the `#' character are ignored.

       Keywords may be specified multiple times within  the  configuration  file.   They  are  as
       follows:

       listen on address
              OpenNTPd has the ability to sync the local clock to remote NTP servers and, if this
              directive is specified, can act as NTP  server  itself,  redistributing  the  local
              clock.

              Specify  a  local  IP  address or a hostname the ntpd(8) daemon should listen on to
              enable remote clients synchronization.  If it appears multiple times, ntpd(8)  will
              listen  on  each given address.  If `*' is given as an address, ntpd(8) will listen
              on all local addresses.  ntpd(8) does not listen on any address  by  default.   For
              example:

              listen on *

              or

              listen on 127.0.0.1
              listen on ::1

       sensor device [correction microseconds] [weight weight-value]
              Specify  a timedelta sensor device ntpd(8) should use.  The sensor can be specified
              multiple times: ntpd(8) will use each given  sensor  that  actually  exists.   Non-
              existent sensors are ignored.  If `*' is given as device name, ntpd(8) will use all
              timedelta sensors it finds.  ntpd(8) does not use any timedelta sensor by  default.
              For example:

              sensor *
              sensor udcf0

              An  optional correction in microseconds can be given to compensate for the sensor's
              offset.  The maximum correction is 127 seconds.  For example, if a  DCF77  receiver
              is lagging 15ms behind actual time:

              sensor udcf0 correction 15000

       server address [weight weight-value]
              Specify  the  IP address or the hostname of an NTP server to synchronize to.  If it
              appears multiple times, ntpd(8) will try to  synchronize  to  all  of  the  servers
              specified.   If a hostname resolves to multiple IPv4 and/or IPv6 addresses, ntpd(8)
              uses the first address.  If it does not get a reply, ntpd(8) retries with the  next
              address and continues to do so until a working address is found.  For example:

              server 10.0.0.2 weight 5
              server ntp.example.org weight 1

              To  provide  redundancy,  it  is  good  practice to configure multiple servers.  In
              general, best accuracy is obtained  by  using  servers  that  have  a  low  network
              latency.

       servers address [weight weight-value]
              As  with server, specify the IP address or hostname of an NTP server to synchronize
              to.  If it appears multiple times, ntpd(8) will try to synchronize to  all  of  the
              servers  specified.   Should the hostname resolve to multiple IP addresses, ntpd(8)
              will try to synchronize to all of them.  For example:

              servers pool.ntp.org

FILES

       /etc/openntpd/ntpd.conf
              default ntpd(8) configuration file

SEE ALSO

       ntpd(8), sysctl(8)

HISTORY

       The ntpd.conf file format first appeared in OpenBSD 3.6 .

                                   $Mdocdate: October 2 2007 $                       NTPD.CONF(5)