Man Pages

ntp_misc(5) - phpMan ntp_misc(5) - phpMan

Command: man perldoc info search(apropos)  

ntp_misc(5)                                                        ntp_misc(5)

       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.

       driftfile driftfile { 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 initial frequency and then updated once per hour or more with the
               current frequency computed by the daemon. If the file name is specified, 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 sys-
               tem  links,  symbolic or otherwise, should be avoided.  The parameter tolerance is the wander threshold
               to skip writing the new value. If the value of wander computed from recent frequency changes is greater
               than  this  threshold the file will be updated once per hour. If below the threshold, the file will not
               be written.

       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 program.

               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

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

                       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  sup-
                       port is available, 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.

               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, command 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).

       interface [listen | ignore | drop] [all | ipv4 | ipv6 | wildcard | name | address[/prefixlen]]
               This command controls which network addresses ntpd opens, and whether input is dropped without process-
               ing. The first parameter determines the action for addresses which match  the  second  parameter.  That
               parameter  specifies  a class of addresses, or a specific interface name, or an address. In the address
               case, prefixlen determines how many bits must match for this rule to  apply.  ignore  prevents  opening
               matching addresses, drop causes ntpd to open the address and drop all received packets without examina-
               tion. Multiple interface commands can be used. The last rule which matches a particular address  deter-
               mines  the action for it. interface commands are disabled if any -I, --interface, -L, or --novirtualips
               command-line options are used. If none of those options are used and no interface actions are specified
               in  the configuration file, all available network addresses are opened. The nic command is an alias for

       leapfile leapfile
               This command loads the NIST leapseconds file  and  initializes  the  leapsecond  values  for  the  next
               leapsecond  time,  expiration time and TAI offset. The file can be obtained directly from NIST national
               time servers using ftp as the ASCII file pub/leap-seconds.  While not strictly a security function, the
               Autokey  protocol  provides  means to securely retrieve the current or updated leapsecond values from a

       logconfig configkeyword
               This command controls the amount and type of output written to the system syslog facility or the alter-
               nate  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 mes-
               sages (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 pre-
               fix 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
               =syncall +sysevents +sysstatus.  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 following minimum message  configuration  could  be  useful:
               logconfig  =syncall  +clockall  This  configuration will list all clock information and synchronization
               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.

       saveconfigdir directory_path
               Specify  the  directory in which to write configuration snapshots requested with ntpq's saveconfig com-
               mand. If saveconfigdir does not appear in the configuration file, saveconfig requests are  rejected  by

       setvar variable [default]
               This  command  adds an additional system variable. These variables 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 variables 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 variables.

       tinker [ allan allan | dispersion dispersion | freq freq | huffpuff huffpuff  |  panic  panic  |  step  step  |
       stepout stepout ]
               This command alters certain system variables used by the clock discipline algorithm. The default values
               of  these  variables  have  been carefully optimized for a wide range of network speeds and reliability
               expectations. Very rarely is it necessary to change the default values; but, some  folks  can't  resist
               twisting the knobs. The options are as follows:

               allan allan
                       Spedifies  the Allan intercept, which is a parameter of the PLL/FLL clock discipline algorithm,
                       in seconds with default 1500 s.

               dispersion dispersion
                       Specifies the dispersion increase rate in parts-per-million (PPM) with default 15 PPM.

               freq freq
                       Spedifies the frequency offset in parts-per-million (PPM) with default the value  in  the  fre-
                       quency file.

               huffpuff huffpuff
                       Spedifies the 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  reasonable  value
                       is 7200 (2 hours).

               panic panic
                       Spedifies  the panic threshold in seconds with 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
                       Spedifies the step threshold in seconds. The default without this command is 0.128 s. If set to
                       zero,  step  adjustments  will never occur. Note: The kernel time discipline is disabled if the
                       step threshold is set to zero or greater than 0.5 s and the threshold is applied also  to  leap
                       second corrections.

               stepout stepout
                       Specifies  the  stepout threshold in seconds. The default without this command is 900 s. If set
                       to zero, popcorn spikes will not be suppressed.

       tos [ beacon beacon | ceiling ceiling | cohort {0 | 1} | floor floor | maxclock maxclock |  maxdist  maxdist  |
       minclock minclock | mindist mindist | minsane minsane | orphan stratum ]
               This command alters certain system variables used by the the clock selection and clustering algorithms.
               The  default values of these variables have been carefully optimized for a wide range of network speeds
               and reliability expectations. Very rarely is it necessary to change the default values; but, some folks
               can't  resist  twisting  the  knobs. It can be used to select the quality and quantity of peers used to
               synchronize the system clock and is most useful in dynamic server discovery schemes. The options are as

               beacon beacon
                       The manycast server sends packets at intervals of 64 s if less than maxclock servers are avail-
                       able. Otherwise, it sends packets at the beacon interval in seconds. The default is 3600 s. See
                       the Automatic Server Discovery page for further details.

               ceiling ceiling
                       Specify  the  maximum stratum (exclusive) for acceptable server packets. The default is 16. See
                       the Automatic Server Discovery page for further details.

               cohort { 0 | 1 }
                       Specify whether (1) or whether not (0) a server packet will be accepted for the same stratum as
                       the client. The default is 0. See the Automatic Server Discovery page for further details.

               floor floor
                       Specify  the  minimum  stratum (inclusive) for acceptable server packest. The default is 1. See
                       the Automatic Server Discovery page for further details.

               maxclock maxclock
                       Specify the maximum number of servers retained by the server discovery schemes. The default  is
                       10. See the Automatic Server Discovery page for further details.

               maxdist maxdistance
                       Specify  the  synchronization  distance  threshold  used  by the clock selection algorithm. The
                       default is 1.5 s. This determines both the minimum number of packets to set  the  system  clock
                       and  the  maximum  roundtrip  delay. It can be decreased to improve reliability or increased to
                       synchronize clocks on the Moon or planets.

               minclock minclock
                       Specify the number of servers used by the clustering algorithm as the minimum to include on the
                       candidate list. The default is 3. This is also the number of servers to be averaged by the com-
                       bining algorithm.

               mindist mindistance
                       Specify the minimum distance used by the selection and anticlockhop  algorithm.  Larger  values
                       increase  the  tolerance  for outliers; smaller values increase the selectivity. The default is
                       .001 s. In some cases, such as reference clocks with high jitter and a PPS signal, it is useful
                       to increase the value to insure the intersection interval is always nonempty.

               minsane minsane
                       Specify  the number of servers used by the selection algorithm as the minimum to set the system
                       clock. The default is 1 for legacy purposes;  however,  for  critical  applications  the  value
                       should be somewhat higher but less than minclock.

               orphan stratum
                       Specify  the orphan stratum with default 16. If less than 16 this is the stratum assumed by the
                       root servers. See the Association Management page for further details.

       trap host_address [port port_number] [interface interfSace_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 specified, the message is sent with a source address of the local
               interface  the message is sent through. Note that on a multihomed 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

       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.

       dscp dscp
               This  command  specifies  the  Differentiated Services Code Point (DSCP) value that is used in sent NTP
               packets. The default value is 48 for Class Selector 6 (CS6).


       The official HTML documentation.

       This file was automatically generated from HTML source.