NTPD(1)                       Programmer's Manual                      NTPD(1)



NAME
       ntpd - NTP daemon program

SYNOPSIS
       ntpd [-flag [value]]... [--opt-name [[=| ]value]]...

       All arguments must be options.

DESCRIPTION
       This manual page briefly documents the ntpd command.


OPTIONS
       -4, --ipv4
              Force IPv4 DNS name resolution.  This option must not appear in
              combination with any of the following options: ipv6.

              Force DNS resolution of following host names on the command line
              to the IPv4 namespace.

       -6, --ipv6
              Force IPv6 DNS name resolution.  This option must not appear in
              combination with any of the following options: ipv4.

              Force DNS resolution of following host names on the command line
              to the IPv6 namespace.

       -a, --authreq
              Require crypto authentication.  This option must not appear in
              combination with any of the following options: authnoreq.

              Require cryptographic authentication for broadcast client,
              multicast client and symmetric passive associations.  This is
              the default.

       -A, --authnoreq
              Do not require crypto authentication.  This option must not
              appear in combination with any of the following options:
              authreq.

              Do not require cryptographic authentication for broadcast
              client, multicast client and symmetric passive associations.
              This is almost never a good idea.

       -b, --bcastsync
              Allow us to sync to broadcast servers.



       -c string, --configfile=string
              configuration file name.

              The name and path of the configuration file, /etc/ntp.conf by
              default.

       -d, --debug-level
              Increase output debug message level.  This option may appear an
              unlimited number of times.

              Increase the debugging message output level.

       -D string, --set-debug-level=string
              Set the output debug message level.  This option may appear an
              unlimited number of times.

              Set the output debugging level.  Can be supplied multiple times,
              but each overrides the previous value(s).

       -f string, --driftfile=string
              frequency drift file name.

              The name and path of the frequency file, /etc/ntp.drift by
              default.  This is the same operation as the driftfile driftfile
              configuration specification in the /etc/ntp.conf file.

       -g, --panicgate
              Allow the first adjustment to be Big.  This option may appear an
              unlimited number of times.

              Normally, ntpd exits with a message to the system log if the
              offset exceeds the panic threshold, which is 1000 s by default.
              This option allows the time to be set to any value without
              restriction; however, this can happen only once. If the
              threshold is exceeded after that, ntpd will exit with a message
              to the system log. This option can be used with the -q and -x
              options.  See the tinker configuration file directive for other
              options.

       -i string, --jaildir=string
              Jail directory.

              Chroot the server to the directory jaildir This option also
              implies that the server attempts to drop root privileges at
              startup.  You may need to also specify a -u option.  This option
              is only available if the OS supports adjusting the clock without
              full root privileges.  This option is supported under NetBSD
              (configure with --enable-clockctl ) and Linux (configure with
              --enable-linuxcaps ).

       -I iface, --interface=iface
              Listen on an interface name or address.  This option may appear
              an unlimited number of times.

              Open the network address given, or all the addresses associated
              with the given interface name.  This option may appear multiple
              times.  This option also implies not opening other addresses,
              except wildcard and localhost.  This option is deprecated.
              Please consider using the configuration file interface command,
              which is more versatile.

       -k string, --keyfile=string
              path to symmetric keys.

              Specify the name and path of the symmetric key file.
              /etc/ntp.keys is the default.  This is the same operation as the
              keys keyfile configuration file directive.

       -l string, --logfile=string
              path to the log file.

              Specify the name and path of the log file.  The default is the
              system log file.  This is the same operation as the logfile
              logfile configuration file directive.

       -L, --novirtualips
              Do not listen to virtual interfaces.

              Do not listen to virtual interfaces, defined as those with names
              containing a colon.  This option is deprecated.  Please consider
              using the configuration file interface command, which is more
              versatile.

       -M, --modifymmtimer
              Modify Multimedia Timer (Windows only).

              Set the Windows Multimedia Timer to highest resolution.  This
              ensures the resolution does not change while ntpd is running,
              avoiding timekeeping glitches associated with changes.

       -n, --nofork
              Do not fork.



       -N, --nice
              Run at high priority.

              To the extent permitted by the operating system, run ntpd at the
              highest priority.

       -p string, --pidfile=string
              path to the PID file.

              Specify the name and path of the file used to record ntpd's
              process ID.  This is the same operation as the pidfile pidfile
              configuration file directive.

       -P number, --priority=number
              Process priority.  This option takes an integer number as its
              argument.

              To the extent permitted by the operating system, run ntpd at the
              specified sched_setscheduler(SCHED_FIFO) priority.

       -q, --quit
              Set the time and quit.

              ntpd will exit just after the first time the clock is set. This
              behavior mimics that of the ntpdate program, which is to be
              retired.  The -g and -x options can be used with this option.
              Note: The kernel time discipline is disabled with this option.

       -r string, --propagationdelay=string
              Broadcast/propagation delay.

              Specify the default propagation delay from the
              broadcast/multicast server to this client. This is necessary
              only if the delay cannot be computed automatically by the
              protocol.

       --saveconfigquit=string
              Save parsed configuration and quit.

              Cause ntpd to parse its startup configuration file and save an
              equivalent to the given filename and exit.  This option was
              designed for automated testing.

       -s string, --statsdir=string
              Statistics file location.

              Specify the directory path for files created by the statistics
              facility.  This is the same operation as the statsdir statsdir
              configuration file directive.

       -t tkey, --trustedkey=tkey
              Trusted key number.  This option may appear an unlimited number
              of times.

              Add a key number to the trusted key list.

       -u string, --user=string
              Run as userid (or userid:groupid).

              Specify a user, and optionally a group, to switch to.  This
              option is only available if the OS supports adjusting the clock
              without full root privileges.  This option is supported under
              NetBSD (configure with --enable-clockctl ) and Linux (configure
              with --enable-linuxcaps ).

       -U number, --updateinterval=number
              interval in seconds between scans for new or dropped interfaces.
              This option takes an integer number as its argument.

              Give the time in seconds between two scans for new or dropped
              interfaces.  For systems with routing socket support the scans
              will be performed shortly after the interface change has been
              detected by the system.  Use 0 to disable scanning. 60 seconds
              is the minimum time between scans.

       --var=nvar
              make ARG an ntp variable (RW).  This option may appear an
              unlimited number of times.



       --dvar=ndvar
              make ARG an ntp variable (RW|DEF).  This option may appear an
              unlimited number of times.



       -x, --slew
              Slew up to 600 seconds.

              Normally, the time is slewed if the offset is less than the step
              threshold, which is 128 ms by default, and stepped if above the
              threshold.  This option sets the threshold to 600 s, which is
              well within the accuracy window to set the clock manually.
              Note: Since the slew rate of typical Unix kernels is limited to
              0.5 ms/s, each second of adjustment requires an amortization
              interval of 2000 s.  Thus, an adjustment as much as 600 s will
              take almost 14 days to complete.  This option can be used with
              the -g and -q options.  See the tinker configuration file
              directive for other options.  Note: The kernel time discipline
              is disabled with this option.

       --usepcc
              Use CPU cycle counter (Windows only).

              Attempt to substitute the CPU counter for
              QueryPerformanceCounter.  The CPU counter and
              QueryPerformanceCounter are compared, and if they have the same
              frequency, the CPU counter (RDTSC on x86) is used directly,
              saving the overhead of a system call.

       --pccfreq=string
              Force CPU cycle counter use (Windows only).

              Force substitution the CPU counter for QueryPerformanceCounter.
              The CPU counter (RDTSC on x86) is used unconditionally with the
              given frequency (in Hz).

       -?, --help
              Display extended usage information and exit.

       -!, --more-help
              Extended usage information passed thru pager.

       - [{v|c|n}], --version[={v|c|n}]
              Output version of program and exit.  The default mode is `v', a
              simple version.  The `c' mode will print copyright information
              and `n' will print the full copyright notice.

OPTION PRESETS
       Any option that is not marked as not presettable may be preset by
       loading values from environment variables named:
         NTPD_<option-name> or NTPD

AUTHOR
       David L. Mills and/or others
       Please send bug reports to:  http://bugs.ntp.org, bugs@ntp.org


       see html/copyright.html

       This manual page was AutoGen-erated from the ntpd option definitions.



( 4.2.6p2)                        2010-07-09                           NTPD(1)
