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)