ntp_misc
ntp_misc(5) ntp_misc(5)
NAME
ntp_misc - Miscellaneous Options
broadcastdelay seconds
The broadcast and multicast modes require a special calibra-
tion 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. Typi-
cally (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 addi-
tional time for a modem or ISDN call to complete.
driftfile driftfile
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 with the cur-
rent 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 dae-
mon 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 mea-
sured 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.
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 authenti-
cated using either public key or private key cryptog-
raphy. 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 Pre-
cision 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,
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).
logconfig configkeyword
This command controls the amount and type of output written to
the system syslog facility or the alternate logfile log file.
By default, all output is turned on. All configkeyword key-
words can be prefixed with =, + and -, where = sets the sys-
logmask, + 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: infor-
mational messages (info), event messages (events), statistics
messages (statistics) and status messages (status). Configu-
ration 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 mes-
sage class.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 syn-
chronization 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.
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 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 vari-
ables 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 can be used to alter several system variables in
very exceptional circumstances. It should occur in the config-
uration file before any other configuration options. The
default values of these variables have been carefully opti-
mized for a wide range of network speeds and reliability
expectations. In general, they interact in intricate ways that
are hard to predict and some combinations can result in some
very nasty behavior. 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 sup-
port group. The variables operate as follows:
allan allan
The argument becomes the new value for the minimum
Allan intercept, which is a parameter of the PLL/FLL
clock discipline algorithm. The value in log2 seconds
defaults to 7 (1024 s), which is also the lower limit.
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 fre-
quency offset in parts-per-million. This overrides the
value in the frequency file, if present, and avoids
the initial training state if it is not.
huffpuff huffpuff
The argument becomes the new value for the experimen-
tal 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). There is no
default, since the filter is not enabled unless this
command is given.
panic panic
The argument is the panic threshold, normally 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, which by default
is 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 threshold is set to zero or greater than the
default.
stepout stepout
The argument is the stepout timeout, which by default
is 900 s. It can be set to any positive number in sec-
onds. 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 speci-
fied local interface address. If the port number is unspeci-
fied, 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 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)
