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ntpd(8)				 User Commands			       ntpd(8)



NAME
       ntpd - NTP daemon program

SYNOPSIS
       ntpd  [-flags]  [-flag [value]] [--option-name[[=| ]value]] [ <server1>
       ... <serverN> ]


DESCRIPTION
       The ntpd utility is an operating system daemon which sets and maintains
       the  system  time  of  day  in  synchronism with Internet standard time
       servers.	 It is a complete implementation of the Network Time  Protocol
       (NTP) version 4, as defined by RFC-5905, but also retains compatibility
       with version 3, as defined by  RFC-1305,	 and  versions	1  and	2,  as
       defined by RFC-1059 and RFC-1119, respectively.

       The ntpd utility does most computations in 64-bit floating point arith-
       metic and does relatively clumsy 64-bit	fixed  point  operations  only
       when  necessary	to preserve the ultimate precision, about 232 picosec-
       onds.  While the ultimate precision is  not  achievable	with  ordinary
       workstations  and  networks  of	today,	it may be required with future
       gigahertz CPU clocks and gigabit LANs.

       Ordinarily, ntpd reads the ntp.conf(5) configuration  file  at  startup
       time  in	 order	to determine the synchronization sources and operating
       modes.  It is also possible to specify  a  working,  although  limited,
       configuration  entirely	on  the command line, obviating the need for a
       configuration file.  This may be particularly  useful  when  the	 local
       host  is	 to  be	 configured  as a broadcast/multicast client, with all
       peers being determined by listening to broadcasts at run time.

       If NetInfo support is built into ntpd, then ntpd will attempt  to  read
       its configuration from the NetInfo if the default ntp.conf(5) file can-
       not be read and no file is specified by the -c option.

       Various internal ntpd variables	can  be	 displayed  and	 configuration
       options	altered	 while	the  ntpd  is  running	using  the ntpq(8) and
       ntpdc(8) utility programs.

       When ntpd starts it looks at the value of umask(2), and	if  zero  ntpd
       will set the umask(2) to 022.

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,  mul-
	      ticast  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	debug  verbosity  level.   This	 option	 may appear an
	      unlimited number of times.


       -D number, --set-debug-level=number
	      Set the debug verbosity level.  This option may appear an unlim-
	      ited  number  of	times.	This option takes an integer number as
	      its argument.


       -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  thresh-
	      old 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.

       -G, --force-step-once
	      Step any initial offset correction..

	      Normally,	 ntpd  steps  the  time if the time offset exceeds the
	      step threshold, which is 128 ms by default, and otherwise	 slews
	      the  time.   This option forces the initial offset correction to
	      be stepped,  so  the  highest  time  accuracy  can  be  achieved
	      quickly.	 However,  this	 may also cause the time to be stepped
	      back so this option must not be used if  applications  requiring
	      monotonic	 time  are running.  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)  or	Linux  (configure with
	      --enable-linuxcaps) or Solaris (configure	 with  --enable-solar-
	      isprivs).

       -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 log-
	      file 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.  This option must not appear	 in  combination  with
	      any of the following options: wait-sync.


       -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.  This option must not appear in  combina-
	      tion  with  any  of the following options: saveconfigquit, wait-
	      sync.

	      ntpd will not daemonize and will exit after the clock  is	 first
	      synchronized.  This behavior mimics that of the ntpdate program,
	      which will soon be replaced with a shell script.	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/multi-
	      cast  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.  This option must not appear
	      in  combination  with  any of the following options: quit, wait-
	      sync.

	      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 the specified 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)	 or  Linux  (configure
	      with  --enable-linuxcaps)	 or  Solaris (configure with --enable-
	      solarisprivs).

       -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 unlim-
	      ited number of times.


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


       -w number, --wait-sync=number
	      Seconds  to  wait	 for  first  clock sync.  This option must not
	      appear in combination with any of the following options: nofork,
	      quit,  saveconfigquit.   This  option takes an integer number as
	      its argument.

	      If greater than zero, alters ntpd's  behavior  when  forking  to
	      daemonize.   Instead  of exiting with status 0 immediately after
	      the fork, the parent waits up to the specified number of seconds
	      for  the	child to first synchronize the clock.  The exit status
	      is zero (success) if the clock was synchronized, otherwise it is
	      ETIMEDOUT.   This provides the option for a script starting ntpd
	      to easily wait for the first set of the clock before proceeding.

       -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 direc-
	      tive  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  QueryPerformance-
	      Counter.	 The  CPU counter and QueryPerformanceCounter are com-
	      pared, 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).

       -m, --mdns
	      Register with mDNS as a NTP server.

	      Registers as an NTP server with  the  local  mDNS	 server	 which
	      allows the server to be discovered via mDNS client lookup.

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

       -!, --more-help
	      Pass the extended usage information through a pager.

       --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 load-
       ing values from environment variables named:
	 NTPD_<option-name> or NTPD

USAGE
   How NTP Operates
       The ntpd utility operates by exchanging messages with one or more  con-
       figured	servers	 over  a  range	 of  designated	 poll intervals.  When
       started, whether	 for  the  first  or  subsequent  times,  the  program
       requires	 several  exchanges  from the majority of these servers so the
       signal processing and mitigation algorithms can	accumulate  and	 groom
       the  data  and  set  the	 clock.	  In order to protect the network from
       bursts, the initial poll interval for each server is delayed an	inter-
       val  randomized over a few seconds.  At the default initial poll inter-
       val of 64s, several minutes can elapse before the clock is  set.	  This
       initial	delay  to set the clock can be safely and dramatically reduced
       using the iburst keyword with  the  server  configuration  command,  as
       described in ntp.conf(5).

       Most operating systems and hardware of today incorporate a time-of-year
       (TOY) chip to maintain the time during periods when the power  is  off.
       When  the machine is booted, the chip is used to initialize the operat-
       ing system time.	 After the machine has synchronized to a  NTP  server,
       the  operating  system  corrects	 the  chip  from time to time.	In the
       default case, if ntpd detects that the time on the host	is  more  than
       1000s  from  the	 server	 time, ntpd assumes something must be terribly
       wrong and the only reliable action is for the operator to intervene and
       set the clock by hand.  (Reasons for this include there is no TOY chip,
       or its battery is dead, or that the TOY chip is just of poor  quality.)
       This  causes  ntpd to exit with a panic message to the system log.  The
       -g option overrides this check and the clock will be set to the	server
       time  regardless of the chip time (up to 68 years in the past or future
       -- this is a limitation of the NTPv4 protocol).	However, and  to  pro-
       tect  against  broken  hardware, such as when the CMOS battery fails or
       the clock counter becomes defective, once the clock  has	 been  set  an
       error greater than 1000s will cause ntpd to exit anyway.

       Under  ordinary	conditions,  ntpd  adjusts the clock in small steps so
       that the timescale is effectively continuous  and  without  discontinu-
       ities.	Under  conditions of extreme network congestion, the roundtrip
       delay jitter can exceed three seconds and the synchronization distance,
       which is equal to one-half the roundtrip delay plus error budget terms,
       can become very large.  The  ntpd  algorithms  discard  sample  offsets
       exceeding  128 ms, unless the interval during which no sample offset is
       less than 128 ms exceeds 900s.  The first sample after that, no	matter
       what  the  offset,  steps the clock to the indicated time.  In practice
       this reduces the false alarm rate where the clock is stepped  in	 error
       to a vanishingly low incidence.

       As  the	result	of  this behavior, once the clock has been set it very
       rarely strays more than 128 ms even under extreme cases of network path
       congestion  and	jitter.	  Sometimes,  in particular when ntpd is first
       started without a valid drift file on a system with a  large  intrinsic
       drift  the  error  might	 grow  to exceed 128 ms, which would cause the
       clock to be set backwards if the local clock time is more than 128 s in
       the future relative to the server.  In some applications, this behavior
       may be unacceptable.  There are several solutions, however.  If the  -x
       option is included on the command line, the clock will never be stepped
       and only slew corrections will be used.	But this choice comes  with  a
       cost  that  should  be carefully explored before deciding to use the -x
       option.	The maximum slew rate possible is limited  to  500  parts-per-
       million	(PPM)  as a consequence of the correctness principles on which
       the NTP protocol and algorithm design are  based.   As  a  result,  the
       local  clock  can take a long time to converge to an acceptable offset,
       about 2,000 s for each second  the  clock  is  outside  the  acceptable
       range.	During	this  interval	the local clock will not be consistent
       with any other network clock and the system cannot be used for distrib-
       uted applications that require correctly synchronized network time.

       In  spite  of  the  above  precautions,	sometimes when large frequency
       errors are present the resulting time offsets stray outside the	128-ms
       range  and  an  eventual	 step or slew time correction is required.  If
       following such a correction the frequency error is so  large  that  the
       first  sample  is  outside  the	acceptable range, ntpd enters the same
       state as when the ntp.drift file is not present.	 The  intent  of  this
       behavior	 is  to quickly correct the frequency and restore operation to
       the normal  tracking  mode.   In	 the  most  extreme  cases  (the  host
       time.ien.it  comes  to mind), there may be occasional step/slew correc-
       tions and subsequent frequency corrections.  It helps in these cases to
       use  the	 burst	keyword when configuring the server, but ONLY when you
       have permission to do so from the owner of the target host.

       Finally, in the past many  startup  scripts  would  run	ntpdate(8)  or
       sntp(8)	to  get	 the  system  clock  close  to correct before starting
       ntpd(8), but this was never more than a mediocre hack and is no	longer
       needed.	 If  you  are following the instructions in Starting NTP (Best
       Current Practice) and you still need to	set  the  system  time	before
       starting	 ntpd, please open a bug report and document what is going on,
       and then look at using sntp(8) if you really  need  to  set  the	 clock
       before starting ntpd.

       There  is  a way to start ntpd(8) that often addresses all of the prob-
       lems mentioned above.

   Starting NTP (Best Current Practice)
       First, use the iburst option on your server entries.

       If you can also keep a good ntp.drift file  then	 ntpd(8)  will	effec-
       tively  "warm-start" and your system's clock will be stable in under 11
       seconds' time.

       As soon as possible in the startup  sequence,  start  ntpd(8)  with  at
       least  the -g and perhaps the -N options.  Then, start the rest of your
       "normal" processes.  This will give ntpd(8) as much time as possible to
       get the system's clock synchronized and stable.

       Finally,	 if  you  have processes like dovecot or database servers that
       require monotonically-increasing time, run ntp-wait(8) as late as  pos-
       sible  in  the  boot sequence (perhaps with the -v flag) and after ntp-
       wait(8) exits successfully it is as safe as it will ever	 be  to	 start
       any process that require stable time.

   Frequency Discipline
       The  ntpd  behavior  at	startup depends on whether the frequency file,
       usually ntp.drift, exists.  This file contains the latest  estimate  of
       clock  frequency error.	When the ntpd is started and the file does not
       exist, the ntpd enters a special mode designed to quickly adapt to  the
       particular  system  clock  oscillator  time  and frequency error.  This
       takes approximately 15 minutes, after which the time and frequency  are
       set  to	nominal values and the ntpd enters normal mode, where the time
       and frequency are continuously tracked relative to the  server.	 After
       one hour the frequency file is created and the current frequency offset
       written to it.  When the ntpd is started and the file does  exist,  the
       ntpd  frequency	is  initialized	 from  the file and enters normal mode
       immediately.  After that the current frequency offset is written to the
       file at hourly intervals.

   Operating Modes
       The ntpd utility can operate in any of several modes, including symmet-
       ric active/passive, client/server broadcast/multicast and manycast,  as
       described  in  the  "Association Management" page (available as part of
       the HTML documentation provided in  /usr/share/doc/ntp).	  It  normally
       operates	 continuously  while monitoring for small changes in frequency
       and trimming the clock for the ultimate	precision.   However,  it  can
       operate	in  a  one-time	 mode  where  the time is set from an external
       server and frequency is set from a previously recorded frequency	 file.
       A  broadcast/multicast  or manycast client can discover remote servers,
       compute server-client propagation delay correction factors and  config-
       ure  itself automatically.  This makes it possible to deploy a fleet of
       workstations without specifying configuration details specific  to  the
       local environment.

       By default, ntpd runs in continuous mode where each of possibly several
       external servers is polled at  intervals	 determined  by	 an  intricate
       state  machine.	 The  state  machine measures the incidental roundtrip
       delay jitter and oscillator frequency wander and	 determines  the  best
       poll  interval  using  a	 heuristic algorithm.  Ordinarily, and in most
       operating environments, the state machine will start with 64s intervals
       and  eventually	increase  in steps to 1024s.  A small amount of random
       variation is introduced in order to avoid bunching at the servers.   In
       addition,  should  a  server become unreachable for some time, the poll
       interval is increased in steps to 1024s	in  order  to  reduce  network
       overhead.

       In  some cases it may not be practical for ntpd to run continuously.  A
       common workaround has been to run the ntpdate(8)	 or  sntp(8)  programs
       from a cron(8) job at designated times.	However, these programs do not
       have the crafted signal processing, error checking or mitigation	 algo-
       rithms  of  ntpd.  The -q option is intended for this purpose.  Setting
       this option will cause ntpd to exit just after setting  the  clock  for
       the  first  time.  The procedure for initially setting the clock is the
       same as in continuous mode; most applications  will  probably  want  to
       specify the iburst keyword with the server configuration command.  With
       this keyword a volley of messages are exchanged to groom the  data  and
       the  clock is set in about 10 s.	 If nothing is heard after a couple of
       minutes, the daemon times out and exits.	 After a  suitable  period  of
       mourning, the ntpdate(8) program will be retired.

       When  kernel  support  is  available to discipline the clock frequency,
       which is the case for stock Solaris, Tru64, Linux and FreeBSD, a useful
       feature is available to discipline the clock frequency.	First, ntpd is
       run in continuous mode with selected servers in order  to  measure  and
       record  the intrinsic clock frequency offset in the frequency file.  It
       may take some hours for the frequency and offset to settle down.	  Then
       the  ntpd  is  stopped  and  run in one-time mode as required.  At each
       startup, the frequency is read from the file and initializes the kernel
       frequency.

   Poll Interval Control
       This  version  of NTP includes an intricate state machine to reduce the
       network load while maintaining a quality of synchronization  consistent
       with  the  observed  jitter  and wander.	 There are a number of ways to
       tailor the operation in order enhance accuracy by reducing the interval
       or  to  reduce network overhead by increasing it.  However, the user is
       advised to carefully consider the consequences  of  changing  the  poll
       adjustment  range from the default minimum of 64 s to the default maxi-
       mum of 1,024 s.	The default minimum can be  changed  with  the	tinker
       minpoll	command to a value not less than 16 s.	This value is used for
       all configured associations, unless overridden by the minpoll option on
       the  configuration  command.   Note  that  most device drivers will not
       operate properly if the poll interval is less than 64 s	and  that  the
       broadcast  server  and  manycast	 client associations will also use the
       default, unless overridden.

       In some cases involving dial up or toll services, it may be  useful  to
       increase	 the  minimum  interval	 to  a few tens of minutes and maximum
       interval to a day or so.	 Under normal operation conditions,  once  the
       clock  discipline loop has stabilized the interval will be increased in
       steps from the minimum to  the  maximum.	  However,  this  assumes  the
       intrinsic clock frequency error is small enough for the discipline loop
       correct it.  The capture range of the loop is 500 PPM at an interval of
       64s  decreasing by a factor of two for each doubling of interval.  At a
       minimum of 1,024 s, for example, the capture range is only 31 PPM.   If
       the intrinsic error is greater than this, the drift file ntp.drift will
       have to be specially tailored to reduce the residual error  below  this
       limit.  Once this is done, the drift file is automatically updated once
       per hour and is available to initialize	the  frequency	on  subsequent
       daemon restarts.

   The huff-n'-puff Filter
       In  scenarios  where a considerable amount of data are to be downloaded
       or uploaded over telephone modems, timekeeping quality can be seriously
       degraded.   This	 occurs	 because  the  differential  delays on the two
       directions of transmission can be  quite	 large.	  In  many  cases  the
       apparent time errors are so large as to exceed the step threshold and a
       step correction can occur during and after  the	data  transfer	is  in
       progress.

       The huff-n'-puff filter is designed to correct the apparent time offset
       in these cases.	It depends on knowledge of the propagation delay  when
       no  other  traffic  is present.	In common scenarios this occurs during
       other than work hours.  The filter  maintains  a	 shift	register  that
       remembers the minimum delay over the most recent interval measured usu-
       ally in hours.  Under conditions of severe delay, the  filter  corrects
       the  apparent  offset  using  the sign of the offset and the difference
       between the apparent delay and minimum delay.  The name of  the	filter
       reflects	 the  negative	(huff)	and  positive (puff) correction, which
       depends on the sign of the offset.

       The filter is activated by the tinker command and huffpuff keyword,  as
       described in ntp.conf(5).

ENVIRONMENT
       See OPTION PRESETS for configuration environment variables.

FILES
       /etc/ntp.conf  the default name of the configuration file
       /etc/ntp.drift the default name of the drift file
       /etc/ntp.keys  the default name of the key file

EXIT STATUS
       One of the following exit values will be returned:

       0  (EXIT_SUCCESS)
	      Successful program execution.

       1  (EXIT_FAILURE)
	      The operation failed or the command syntax was not valid.

       70  (EX_SOFTWARE)
	      libopts  had an internal operational error.  Please report it to
	      autogen-users@lists.sourceforge.net.  Thank you.

SEE ALSO
       ntp.conf(5), ntpdate(8), ntpdc(8), ntpq(8), sntp(8)

       In addition to the manual pages provided,  comprehensive	 documentation
       is  available on the world wide web at http://www.ntp.org/.  A snapshot
       of   this   documentation   is	available   in	  HTML	  format    in
       /usr/share/doc/ntp.  David L. Mills, Network Time Protocol (Version 1),
       RFC1059

       David L. Mills, Network Time Protocol (Version 2), RFC1119

       David L. Mills, Network Time Protocol (Version 3), RFC1305

       David L. Mills and J. Martin, Ed. and J. Burbank and W. Kasch,  Network
       Time Protocol Version 4: Protocol and Algorithms Specification, RFC5905

       David  L.  Mills and B. Haberman, Ed., Network Time Protocol Version 4:
       Autokey Specification, RFC5906

       H. Gerstung and C. Elliott and B. Haberman, Ed., Definitions of Managed
       Objects for Network Time Protocol Version 4: (NTPv4), RFC5907

       R.  Gayraud and B. Lourdelet, Network Time Protocol (NTP) Server Option
       for DHCPv6, RFC5908

AUTHORS
       The University of Delaware and Network Time Foundation

COPYRIGHT
       Copyright (C) 1992-2017 The University of  Delaware  and	 Network  Time
       Foundation  all	rights	reserved.   This program is released under the
       terms of the NTP license, <http://ntp.org/license>.

BUGS
       The ntpd utility has gotten rather fat.	While not huge, it has	gotten
       larger than might be desirable for an elevated-priority ntpd running on
       a workstation, particularly since many of the fancy features which con-
       sume  the  space	 were designed more with a busy primary server, rather
       than a high stratum workstation in mind.

       Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org

NOTES
       Portions of this document came from FreeBSD.

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



4.2.8p12			  14 Aug 2018			       ntpd(8)