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ntp_misc(5)							   ntp_misc(5)

NAME
       ntp_misc - Miscellaneous Options

       broadcastdelay seconds
	       The broadcast and multicast modes require a special calibration
	       to determine the network delay between  the  local  and	remote
	       servers.	 Ordinarily, this is done automatically by the initial
	       protocol exchanges between  the	client	and  server.  In  some
	       cases,  the  calibration	 procedure  may fail due to network or
	       server access controls, for example. This command specifies the
	       default	delay  to be used under these circumstances. Typically
	       (for Ethernet), a number between 0.003  and  0.007  seconds  is
	       appropriate. The default when this command is not used is 0.004
	       seconds.

       calldelay delay
	       This option controls the delay in seconds between the first and
	       second packets sent in burst or iburst mode to allow additional
	       time for a modem or ISDN call to complete.

       driftfile driftfile [ minutes  [ tolerance ] ]
	       This command specifies the complete path and name of  the  file
	       used  to	 record	 the  frequency of the local clock oscillator.
	       This is the same operation as the -f command linke  option.  If
	       the file exists, it is read at startup in order to set the ini‐
	       tial frequency and then updated once per hour with the  current
	       frequency  computed  by	the daemon. If the file name is speci‐
	       fied, but the file itself does not exist, the  starts  with  an
	       initial	frequency of zero and creates the file when writing it
	       for the first time. If this command is not  given,  the	daemon
	       will  always start with an initial frequency of zero.  The file
	       format consists of a single line containing a  single  floating
	       point  number,  which  records the frequency offset measured in
	       parts-per-million (PPM). The file is updated by	first  writing
	       the current drift value into a temporary file and then renaming
	       this file to replace the old version. This  implies  that  ntpd
	       must  have write permission for the directory the drift file is
	       located in, and that file system links, symbolic or  otherwise,
	       should be avoided.

	       The  two	 optional values determine how often the file is writ‐
	       ten, and are particuarly useful when is it desirable  to	 avoid
	       spinning	 up  the  disk unnecessarily. The parameter minutes is
	       how often the file will be written. If omitted or less than  1,
	       the  interval will be 60 minutes (one hour). The parameter tol‐
	       erance is the threshold to skip writing the new value.  If  the
	       new value is within tolerance percent of the last value written
	       (compared out to 3 decimal places), the write will be  skipped.
	       The  default  is	 0.0,  which  means  that the write will occur
	       unless the current and previous values are the same.  A	toler‐
	       ance  of	 .1 equates roughly to a difference in the 2nd decimal
	       place.

       enable [ auth | bclient | calibrate | kernel | monitor | ntp  |	pps  |
       stats]

       disable	[  auth | bclient | calibrate | kernel | monitor | ntp | pps |
       stats ]
	       Provides a way to enable or  disable  various  system  options.
	       Flags  not  mentioned  are  unaffected.	Note that all of these
	       flags can be controlled remotely using the ntpdc	 utility  pro‐
	       gram.

	       auth    Enables	the  server  to	 synchronize with unconfigured
		       peers only if the peer has been correctly authenticated
		       using  either  public  key or private key cryptography.
		       The default for this flag is enable.

	       bclient Enables the server to  listen  for  a  message  from  a
		       broadcast  or  multicast	 server,  as in the multicast‐
		       client command with default address.  The  default  for
		       this flag is disable.

	       calibrate
		       Enables the calibrate feature for reference clocks. The
		       default for this flag is disable.

	       kernel  Enables the kernel time discipline, if  available.  The
		       default	for  this  flag is enable if support is avail‐
		       able, otherwise disable.

	       monitor Enables the monitoring facility. See the ntpdc  program
		       and  the	 monlist  command  or further information. The
		       default for this flag is enable.

	       ntp     Enables time and frequency discipline. In effect,  this
		       switch  opens  and  closes  the feedback loop, which is
		       useful for  testing.  The  default  for	this  flag  is
		       enable.

	       pps     Enables	the  pulse-per-second  (PPS)  signal when fre‐
		       quency and time is disciplined by  the  precision  time
		       kernel modifications. See the A Kernel Model for Preci‐
		       sion Timekeeping	 page  for  further  information.  The
		       default for this flag is disable.

	       stats   Enables	the  statistics	 facility.  See the Monitoring
		       Options page for further information. The  default  for
		       this flag is disable

       includefile includefile
	       This  command  allows  additional  configuration commands to be
	       included from a separate file. Include files may be nested to a
	       depth  of five; upon reaching the end of any include file, com‐
	       mand processing resumes in  the	previous  configuration	 file.
	       This  option  is	 useful	 for  sites  that run ntpd on multiple
	       hosts, with (mostly) common options (e.g., a restriction list).

       logconfig configkeyword
	       This command controls the amount and type of output written  to
	       the  system  syslog facility or the alternate logfile log file.
	       All configkeyword keywords can be prefixed with	=,  +  and  -,
	       where  =	 sets  the  syslogmask, + adds and - removes messages.
	       syslog messages can be controlled in four classes (clock, peer,
	       sys  and sync). Within these classes four types of messages can
	       be controlled: informational messages  (info),  event  messages
	       (events),  statistics messages (statistics) and status messages
	       (status).  Configuration keywords are formed  by	 concatenating
	       the  message  class with the event class. The all prefix can be
	       used instead of a message class. A message class	 may  also  be
	       followed	 by  the all keyword to enable/disable all messages of
	       the respective message class. By default, logconfig  output  is
	       set  to	allsync.  Thus, a minimal log configuration could look
	       like this:

	       logconfig=syncstatus +sysevents

	       This would just list the synchronizations state of ntpd and the
	       major system events. For a simple reference server, the follow‐
	       ing minimum message configuration could be useful:

       logconfig=allsync +allclock

	       This configuration will list all clock information and synchro‐
	       nization	 information.  All  other  events  and	messages about
	       peers, system events and so on is suppressed.

       logfile logfile

	       This command specifies the location of an alternate log file to
	       be  used instead of the default system syslog facility. This is
	       the same operation as the -l command line option.

       phone dial1 dial2 ...
	       This command is used in conjunction with the ACTS modem	driver
	       (type  18).  The arguments consist of a maximum of 10 telephone
	       numbers used to dial USNO, NIST or European time services.  The
	       Hayes  command  ATDT is normally prepended to the number, which
	       can contain other modem control codes as well.

       setvar variable [default]
	       This command adds an additional system  variable.  These	 vari‐
	       ables  can be used to distribute additional information such as
	       the access policy. If the variable of the form name = value  is
	       followed by the default keyword, the variable will be listed as
	       part of the default system variables (ntpq rv  command).	 These
	       additional  variables  serve  informational purposes only. They
	       are not related to the protocol other that they can be  listed.
	       The known protocol variables will always override any variables
	       defined via the setvar mechanism. There are three special vari‐
	       ables that contain the names of all variable of the same group.
	       The sys_var_list holds the names of all system  variables.  The
	       peer_var_list  holds  the  names	 of all peer variables and the
	       clock_var_list holds the names of  the  reference  clock	 vari‐
	       ables.

       tinker  [  allan	 allan	| dispersion dispersion | freq freq | huffpuff
       huffpuff | panic panic | step step | stepout stepout ]
	       This command can be used to alter several system	 variables  in
	       very exceptional circumstances. It should occur in the configu‐
	       ration file before any other configuration options. The default
	       values  of  these variables have been carefully optimized for a
	       wide range of network speeds and reliability  expectations.  In
	       general,	 they interact in intricate ways that are hard to pre‐
	       dict and some combinations can result in some very nasty behav‐
	       ior.  Very rarely is it necessary to change the default values;
	       but, some folks can't resist twisting the knobs anyway and this
	       command	is for them. Emphasis added: twisters are on their own
	       and can expect no help from the support group.	The  variables
	       operate as follows:

	       allan allan
		       The argument becomes the new value for the Allan inter‐
		       cept, which is a parameter of the PLL/FLL clock	disci‐
		       pline  algorithm.  The value is in seconds with default
		       1500 s, which is appropriate for most computer clocks.

	       dispersion dispersion
		       The argument becomes the new value for  the  dispersion
		       increase rate, normally .000015 s/s.

	       freq freq
		       The argument becomes the initial value of the frequency
		       offset in parts-per-million. This overrides  the	 value
		       in  the frequency file, if present, and avoids the ini‐
		       tial training state if it is not.

	       huffpuff huffpuff
		       The argument becomes the new value for the experimental
		       huff-n'-puff  filter  span,  which  determines the most
		       recent interval the algorithm will search for a minimum
		       delay. The lower limit is 900 s (15 m), but a more rea‐
		       sonable value is 7200 (2 hours). There is  no  default,
		       since  the filter is not enabled unless this command is
		       given.

	       panic panic
		       The argument is the panic threshold, by default 1000 s.
		       If  set to zero, the panic sanity check is disabled and
		       a clock offset of any value will be accepted.

	       step step
		       The argument is the step threshold, by default 0.128 s.
		       It can be set to any positive number in seconds. If set
		       to zero, step adjustments will never occur.  Note:  The
		       kernel  time discipline is disabled if the step thresh‐
		       old is set to zero or greater than the default.

	       stepout stepout
		       The argument is the stepout timeout, by default 900  s.
		       It can be set to any positive number in seconds. If set
		       to zero, the stepout pulses will not be suppressed.

       trap host_address [port port_number] [interface interface_address]
	       This command configures a  trap	receiver  at  the  given  host
	       address and port number for sending messages with the specified
	       local interface address. If the port number is  unspecified,  a
	       value  of 18447 is used. If the interface address is not speci‐
	       fied, the message is sent with a source address	of  the	 local
	       interface  the  message	is sent through. Note that on a multi‐
	       homed host the interface used may vary from time to  time  with
	       routing	changes.   The	trap receiver will generally log event
	       messages and other information from the server in a  log	 file.
	       While  such  monitor  programs  may also request their own trap
	       dynamically, configuring a trap receiver will  ensure  that  no
	       messages are lost when the server is started.

       ttl hop ...
	       This  command  specifies	 a  list  of  TTL values in increasing
	       order. up to 8 values can be specified. In manycast mode	 these
	       values  are  used  in  turn  in	an  expanding-ring search. The
	       default is eight multiples of 32 starting at 31.

FILES
       ntp.drift frequency compensation (PPM)

SEE ALSO
       ntp.conf(5)

       Primary source of documentation: /usr/share/doc/ntp-*

       This file was automatically generated from HTML source.

								   ntp_misc(5)
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