NAME

       ntpd - "Network Time Protocol daemon"

SYNOPSIS

       ntpd [-dnSsv] [-f file] [-p file]

DESCRIPTION

       The  ntpd  daemon  synchronizes the local clock to one or more remote NTP servers or local
       timedelta sensors.  ntpd 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 than 128ms are logged using syslog(3) with LOG_INFO priority.
       The threshold value is chosen to avoid having local clock  drift  thrash  the  log  files.
       Should ntpd be started with the -d option, all calls to adjtime(2) will be logged.

       When ntpd starts up, it reads settings from a configuration file, typically 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.

       -p file
              Write pid to file

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

       -n     Configtest mode.  Only check the configuration file for validity.

       -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 correction, eliminating the need to run rdate(8)
              before starting .

       -v     This option allows ntpd to send DEBUG priority messages to syslog.

              When ntpd receives a SIGINFO signal, it will write its peer and  sensor  status  to
              syslog.

FILES

       /etc/openntpd/ntpd.conf
              default ntpd configuration file

       /var/lib/openntpd/ntpd.drift
              drift  file,  written  by  ntpd periodically and used at startup to get the initial
              clock drift

SEE ALSO

       date(1), adjfreq(2), adjtime(2), ntpd.conf(5), rdate(8), timed(8)

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

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

HISTORY

       The ntpd program first appeared in OpenBSD 3.6 .

                                  $Mdocdate: November 10 2007 $                           NTPD(8)