4 @cindex NTP daemon program
7 # EDIT THIS FILE WITH CAUTION (ntpd-opts.texi)
9 # It has been AutoGen-ed Sunday August 17, 2008 at 05:20:12 AM EDT
10 # From the definitions ntpd-opts.def
11 # and the template file aginfo.tpl
13 This program has no explanation.
17 This section was generated by @strong{AutoGen},
18 the aginfo template and the option descriptions for the @command{ntpd} program. It documents the ntpd usage text and option meanings.
20 This software is released under a specialized copyright license.
23 * ntpd usage:: ntpd usage help (-?)
24 * ntpd authnoreq:: authnoreq option (-A)
25 * ntpd authreq:: authreq option (-a)
26 * ntpd bcastsync:: bcastsync option (-b)
27 * ntpd configfile:: configfile option (-c)
28 * ntpd debug-level:: debug-level option (-d)
29 * ntpd driftfile:: driftfile option (-f)
30 * ntpd dvar:: dvar option (-V)
31 * ntpd interface:: interface option (-I)
32 * ntpd ipv4:: ipv4 option (-4)
33 * ntpd ipv6:: ipv6 option (-6)
34 * ntpd jaildir:: jaildir option (-i)
35 * ntpd keyfile:: keyfile option (-k)
36 * ntpd logfile:: logfile option (-l)
37 * ntpd modifymmtimer:: modifymmtimer option (-M)
38 * ntpd nice:: nice option (-N)
39 * ntpd nofork:: nofork option (-n)
40 * ntpd novirtualips:: novirtualips option (-L)
41 * ntpd panicgate:: panicgate option (-g)
42 * ntpd pidfile:: pidfile option (-p)
43 * ntpd priority:: priority option (-P)
44 * ntpd propagationdelay:: propagationdelay option (-r)
45 * ntpd quit:: quit option (-q)
46 * ntpd set-debug-level:: set-debug-level option (-D)
47 * ntpd slew:: slew option (-x)
48 * ntpd statsdir:: statsdir option (-s)
49 * ntpd trustedkey:: trustedkey option (-t)
50 * ntpd updateinterval:: updateinterval option (-U)
51 * ntpd user:: user option (-u)
52 * ntpd var:: var option (-v)
56 @subsection ntpd usage help (-?)
59 This is the automatically generated usage text for ntpd:
63 ntpd - NTP daemon program - Ver. 4.2.5p113
64 USAGE: ntpd [ -<flag> [<val>] | --<name>[@{=| @}<val>] ]...
65 Flg Arg Option-Name Description
66 -4 no ipv4 Force IPv4 DNS name resolution
67 -6 no ipv6 Force IPv6 DNS name resolution
68 - an alternate for ipv4
69 -a no authreq Require crypto authentication
70 - prohibits these options:
72 -A no authnoreq Do not require crypto authentication
73 - prohibits these options:
75 -b no bcastsync Allow us to sync to broadcast servers
76 -c Str configfile configuration file name
77 -d no debug-level Increase output debug message level
78 - may appear multiple times
79 -D Str set-debug-level Set the output debug message level
80 - may appear multiple times
81 -f Str driftfile frequency drift file name
82 -g no panicgate Allow the first adjustment to be Big
83 -I Str interface Listen on the specified interface or IP
84 - may appear multiple times
85 -k Str keyfile path to symmetric keys
86 -l Str logfile path to the log file
87 -L no novirtualips Do not listen to virtual IPs
88 -n no nofork Do not fork
89 -N no nice Run at high priority
90 -p Str pidfile path to the PID file
91 -P Num priority Process priority
92 -q no quit Set the time and quit
93 -r Str propagationdelay Broadcast/propagation delay
94 -s Str statsdir Statistics file location
95 -t Str trustedkey Trusted key number
96 - may appear multiple times
97 -U Num updateinterval interval in seconds between scans for new or dropped interfaces
98 Str var make ARG an ntp variable (RW)
99 - may appear multiple times
100 Str dvar make ARG an ntp variable (RW|DEF)
101 - may appear multiple times
102 -x no slew Slew up to 600 seconds
103 opt version Output version information and exit
104 -? no help Display usage information and exit
105 -! no more-help Extended usage information passed thru pager
107 Options are specified by doubled hyphens and their name
108 or by a single hyphen and the flag character.
110 The following option preset mechanisms are supported:
111 - examining environment variables named NTPD_*
115 please send bug reports to: http://bugs.ntp.org, bugs@@ntp.org
120 @subsection ipv4 option (-4)
123 This is the ``force ipv4 dns name resolution'' option.
125 This option has some usage constraints. It:
128 is a member of the ipv4 class of options.
131 Force DNS resolution of following host names on the command line
132 to the IPv4 namespace.
135 @subsection ipv6 option (-6)
138 This is the ``force ipv6 dns name resolution'' option.
140 This option has some usage constraints. It:
143 is a member of the ipv4 class of options.
146 Force DNS resolution of following host names on the command line
147 to the IPv6 namespace.
150 @subsection authreq option (-a)
153 This is the ``require crypto authentication'' option.
155 This option has some usage constraints. It:
158 must not appear in combination with any of the following options:
162 Require cryptographic authentication for broadcast client,
163 multicast client and symmetric passive associations.
167 @subsection authnoreq option (-A)
168 @cindex ntpd-authnoreq
170 This is the ``do not require crypto authentication'' option.
172 This option has some usage constraints. It:
175 must not appear in combination with any of the following options:
179 Do not require cryptographic authentication for broadcast client,
180 multicast client and symmetric passive associations.
181 This is almost never a good idea.
184 @subsection bcastsync option (-b)
185 @cindex ntpd-bcastsync
187 This is the ``allow us to sync to broadcast servers'' option.
190 @node ntpd configfile
191 @subsection configfile option (-c)
192 @cindex ntpd-configfile
194 This is the ``configuration file name'' option.
195 The name and path of the configuration file,
199 @node ntpd debug-level
200 @subsection debug-level option (-d)
201 @cindex ntpd-debug-level
203 This is the ``increase output debug message level'' option.
205 This option has some usage constraints. It:
208 may appear an unlimited number of times.
210 must be compiled in by defining @code{DEBUG} during the compilation.
213 Increase the debugging message output level.
215 @node ntpd set-debug-level
216 @subsection set-debug-level option (-D)
217 @cindex ntpd-set-debug-level
219 This is the ``set the output debug message level'' option.
221 This option has some usage constraints. It:
224 may appear an unlimited number of times.
226 must be compiled in by defining @code{DEBUG} during the compilation.
229 Set the output debugging level. Can be supplied multiple times,
230 but each overrides the previous value(s).
233 @subsection driftfile option (-f)
234 @cindex ntpd-driftfile
236 This is the ``frequency drift file name'' option.
237 The name and path of the frequency file,
240 This is the same operation as the
242 configuration specification in the
247 @subsection panicgate option (-g)
248 @cindex ntpd-panicgate
250 This is the ``allow the first adjustment to be big'' option.
253 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,
255 will exit with a message to the system log. This option can be used with the
262 configuration file directive for other options.
265 @subsection jaildir option (-i)
268 This is the ``jail directory'' option.
269 Chroot the server to the directory
272 This option also implies that the server attempts to drop root privileges at startup (otherwise, chroot gives very little additional security), and it is only available if the OS supports to run the server without full root privileges.
273 You may need to also specify a
278 @subsection interface option (-I)
279 @cindex ntpd-interface
281 This is the ``listen on interface'' option.
283 This option has some usage constraints. It:
286 may appear an unlimited number of times.
292 @subsection keyfile option (-k)
295 This is the ``path to symmetric keys'' option.
296 Specify the name and path of the symmetric key file.
299 This is the same operation as the
301 configuration file directive.
304 @subsection logfile option (-l)
307 This is the ``path to the log file'' option.
308 Specify the name and path of the log file.
309 The default is the system log file.
310 This is the same operation as the
312 configuration file directive.
314 @node ntpd novirtualips
315 @subsection novirtualips option (-L)
316 @cindex ntpd-novirtualips
318 This is the ``do not listen to virtual ips'' option.
319 Do not listen to virtual IPs. The default is to listen.
321 @node ntpd modifymmtimer
322 @subsection modifymmtimer option (-M)
323 @cindex ntpd-modifymmtimer
325 This is the ``modify multimedia timer (windows only)'' option.
327 This option has some usage constraints. It:
330 must be compiled in by defining @code{SYS_WINNT} during the compilation.
333 Set the Windows Multimedia Timer to highest resolution.
336 @subsection nofork option (-n)
339 This is the ``do not fork'' option.
343 @subsection nice option (-N)
346 This is the ``run at high priority'' option.
347 To the extent permitted by the operating system, run
349 at the highest priority.
352 @subsection pidfile option (-p)
355 This is the ``path to the pid file'' option.
356 Specify the name and path of the file used to record
359 This is the same operation as the
361 configuration file directive.
364 @subsection priority option (-P)
365 @cindex ntpd-priority
367 This is the ``process priority'' option.
368 To the extent permitted by the operating system, run
371 sched_setscheduler(SCHED_FIFO)
375 @subsection quit option (-q)
378 This is the ``set the time and quit'' option.
380 will exit just after the first time the clock is set. This behavior mimics that of the
382 program, which is to be retired.
387 options can be used with this option.
388 Note: The kernel time discipline is disabled with this option.
390 @node ntpd propagationdelay
391 @subsection propagationdelay option (-r)
392 @cindex ntpd-propagationdelay
394 This is the ``broadcast/propagation delay'' option.
395 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.
397 @node ntpd updateinterval
398 @subsection updateinterval option (-U)
399 @cindex ntpd-updateinterval
401 This is the ``interval in seconds between scans for new or dropped interfaces'' option.
402 Give the time in seconds between two scans for new or dropped interfaces.
403 For systems with routing socket support the scans will be performed shortly after the interface change
404 has been detected by the system.
405 Use 0 to disable scanning.
408 @subsection statsdir option (-s)
409 @cindex ntpd-statsdir
411 This is the ``statistics file location'' option.
412 Specify the directory path for files created by the statistics facility.
413 This is the same operation as the
415 configuration file directive.
417 @node ntpd trustedkey
418 @subsection trustedkey option (-t)
419 @cindex ntpd-trustedkey
421 This is the ``trusted key number'' option.
423 This option has some usage constraints. It:
426 may appear an unlimited number of times.
429 Add a key number to the trusted key list.
432 @subsection user option (-u)
435 This is the ``run as userid (or userid:groupid)'' option.
436 Specify a user, and optionally a group, to switch to.
437 This option is only available if the OS supports to run the server without full root privileges.
438 Currently, this option is supported under NetBSD (configure with
440 ) and Linux (configure with
445 @subsection var option (-v)
448 This is the ``make arg an ntp variable (rw)'' option.
450 This option has some usage constraints. It:
453 may appear an unlimited number of times.
459 @subsection dvar option (-V)
462 This is the ``make arg an ntp variable (rw|def)'' option.
464 This option has some usage constraints. It:
467 may appear an unlimited number of times.
473 @subsection slew option (-x)
476 This is the ``slew up to 600 seconds'' option.
477 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.
478 This option sets the threshold to 600 s, which is well within the accuracy window to set the clock manually.
479 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.
480 Thus, an adjustment as much as 600 s will take almost 14 days to complete.
481 This option can be used with the
488 configuration file directive for other options.
489 Note: The kernel time discipline is disabled with this option.