ntpdate(1M)                                                     ntpdate(1M)

NAME
     ntpdate - set date and time by means of NTP

SYNOPSIS
     ntpdate [-bds] [-o version#] [-p timestamps] [-t timeout] server ...

DESCRIPTION
     ntpdate sets the local date and time by polling the NTP (Network Time
     Protocol) server(s) on the system(s) specified by arguments to estab-
     lish the correct time. The command must be executed locally on the
     system by the root user. A number of timestamps are received from each
     of the servers specified, the most suitable of which is found using
     the NTP algorithms used to select an NTP timer.

     ntpdate can be incorporated into a start script to set the time at
     system startup and/or can be executed regularly by cron(1M). The reli-
     ability and accuracy of ntpdate is increased considerably if a large
     number of servers are in use. A single server can be used, although a
     minimum of three to four servers demonstrate better results and reduce
     susceptibility to server failure.

     ntpdate sets two different processes for setting the local time. If
     ntpdate establishes that the difference between the local time and the
     selected time stamp is more than 0.5 seconds, the local time is set
     using settimeofday(3C). If the difference is less than 0.5 seconds,
     the local time is adjusted by calling adjtime(2). It is normally
     better always to set the system clock at startup.

OPTIONS
     -b   This option forces the use of settimeofday(3C) to adjust the
          local time.

     -s   This option instructs ntpdate to record actions using the
          syslog(3C) function instead of recording them to standard output.
          This option is offered if ntpdate is executed by cron(1M).

     -d   This option can be used to simulate an ntpdate action, i.e.
          without actually executing it. Information for the diagnostic
          tool is also output. By default, ntpdate is specified in the
          packages being dispatched as an implementation of the NTP version
          2.

     -o version#
          This option can be used to specify a version number other than
          the default value 3 in the NTP packages distributed. Possible
          values are 1, 2 or 3.

     -p timestamps
          This option can be used to set the number of timestamps contained
          in ntpdate to 1 through 8. The default value is 4.





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ntpdate(1M)                                                     ntpdate(1M)

     -t timeout
          This option can be used to specify the time that the system
          should wait for a response. The response waiting time is rounded
          up to a multiple of 0.2 seconds. The default value is 1 second.

     ntpdate does not set the local time if in.xntpd(1M) is running on the
     same system.

SEE ALSO
     in.xntpd(1M), ntpq(1M), ntptrace(1M).












































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