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NTPD(8)                   BSD System Manager's Manual                  NTPD(8)

NAME
     ntpd -- Network Time Protocol daemon

SYNOPSIS
     ntpd [-dSs] [-f file]

DESCRIPTION
     The ntpd daemon synchronizes the local clock to one or more remote NTP
     servers, and can also act as an NTP server itself, redistributing the
     local time.  It implements the Simple Network Time Protocol version 4, as
     described in RFC 2030, and the Network Time Protocol version 3, as
     described in RFC 1305.

     ntpd uses the adjtime(2) system call to correct the local system time
     without causing time jumps.  Adjustments larger then 128ms are logged
     using syslog(3).  The threshold value is chosen to avoid local clock
     drift thrash the log files.  Should ntpd be started with -d option all
     calls to adjtime(2) will be logged.

     When ntpd starts up, it reads settings from a configuration file, typi-
     cally ntpd.conf(5).

     The options are as follows:

     -d          Do not daemonize.  If this option is specified, ntpd will run
                 in the foreground and log to stderr.

     -f file     Use file as the configuration file, instead of the default
                 /etc/ntpd.conf.

     -S          Do not set the time immediately at startup.  This is the
                 default.

     -s          Set the time immediately at startup if the local clock is off
                 by more than 180 seconds.  Allows for a large time correc-
                 tion, eliminating the need to run rdate(8) before starting
                 ntpd.  Currently, the -s option is added unconditionally in
                 rc(8).  Make sure to specify the -S option (add/edit
                 ntpd_flags in rc.conf.local(8)) if this behaviour is not
                 desired.

FILES
     /etc/ntpd.conf     default ntpd configuration file

SEE ALSO
     date(1), adjtime(2), ntpd.conf(5), rc(8), rc.conf(8), rdate(8), timed(8)

     Network Time Protocol (Version 3), RFC 1305, March 1992.

     Simple Network Time Protocol (SNTP) Version 4, RFC 2030, October 1996.

HISTORY
     The ntpd program first appeared in OpenBSD 3.6.

BSD                              July 9, 2004                              BSD