4 @cindex NTP daemon program
7 # EDIT THIS FILE WITH CAUTION (ntpd-opts.texi)
9 # It has been AutoGen-ed Tuesday December 8, 2009 at 08:13:12 AM EST
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. 4.2.5p247-RC
64 USAGE: ntpd [ -<flag> [<val>] | --<name>[@{=| @}<val>] ]...
65 Flg Arg Option-Name Description
66 -4 no ipv4 Force IPv4 DNS name resolution
67 - prohibits these options:
69 -6 no ipv6 Force IPv6 DNS name resolution
70 - prohibits these options:
72 -a no authreq Require crypto authentication
73 - prohibits these options:
75 -A no authnoreq Do not require crypto authentication
76 - prohibits these options:
78 -b no bcastsync Allow us to sync to broadcast servers
79 -c Str configfile configuration file name
80 -d no debug-level Increase output debug message level
81 - may appear multiple times
82 -D Str set-debug-level Set the output debug message level
83 - may appear multiple times
84 -f Str driftfile frequency drift file name
85 -g no panicgate Allow the first adjustment to be Big
86 - may appear multiple times
87 -i --- jaildir built without --enable-clockctl or --enable-linuxcaps
88 -I Str interface Listen on an interface name or address
89 - may appear multiple times
90 -k Str keyfile path to symmetric keys
91 -l Str logfile path to the log file
92 -L no novirtualips Do not listen to virtual interfaces
93 -n no nofork Do not fork
94 -N no nice Run at high priority
95 -p Str pidfile path to the PID file
96 -P Num priority Process priority
97 -q no quit Set the time and quit
98 -r Str propagationdelay Broadcast/propagation delay
99 Str saveconfigquit Save parsed configuration and quit
100 -s Str statsdir Statistics file location
101 -t Str trustedkey Trusted key number
102 - may appear multiple times
103 -u --- user built without --enable-clockctl or --enable-linuxcaps
104 -U Num updateinterval interval in seconds between scans for new or dropped interfaces
105 Str var make ARG an ntp variable (RW)
106 - may appear multiple times
107 Str dvar make ARG an ntp variable (RW|DEF)
108 - may appear multiple times
109 -x no slew Slew up to 600 seconds
110 opt version Output version information and exit
111 -? no help Display extended usage information and exit
112 -! no more-help Extended usage information passed thru pager
114 Options are specified by doubled hyphens and their name
115 or by a single hyphen and the flag character.
117 The following option preset mechanisms are supported:
118 - examining environment variables named NTPD_*
122 please send bug reports to: http://bugs.ntp.org, bugs@@ntp.org
127 @subsection ipv4 option (-4)
130 This is the ``force ipv4 dns name resolution'' option.
132 This option has some usage constraints. It:
135 is a member of the ipv4 class of options.
138 Force DNS resolution of following host names on the command line
139 to the IPv4 namespace.
142 @subsection ipv6 option (-6)
145 This is the ``force ipv6 dns name resolution'' option.
147 This option has some usage constraints. It:
150 is a member of the ipv4 class of options.
153 Force DNS resolution of following host names on the command line
154 to the IPv6 namespace.
157 @subsection authreq option (-a)
160 This is the ``require crypto authentication'' option.
162 This option has some usage constraints. It:
165 must not appear in combination with any of the following options:
169 Require cryptographic authentication for broadcast client,
170 multicast client and symmetric passive associations.
174 @subsection authnoreq option (-A)
175 @cindex ntpd-authnoreq
177 This is the ``do not require crypto authentication'' option.
179 This option has some usage constraints. It:
182 must not appear in combination with any of the following options:
186 Do not require cryptographic authentication for broadcast client,
187 multicast client and symmetric passive associations.
188 This is almost never a good idea.
191 @subsection bcastsync option (-b)
192 @cindex ntpd-bcastsync
194 This is the ``allow us to sync to broadcast servers'' option.
197 @node ntpd configfile
198 @subsection configfile option (-c)
199 @cindex ntpd-configfile
201 This is the ``configuration file name'' option.
202 The name and path of the configuration file,
206 @node ntpd debug-level
207 @subsection debug-level option (-d)
208 @cindex ntpd-debug-level
210 This is the ``increase output debug message level'' option.
212 This option has some usage constraints. It:
215 may appear an unlimited number of times.
217 must be compiled in by defining @code{DEBUG} during the compilation.
220 Increase the debugging message output level.
222 @node ntpd set-debug-level
223 @subsection set-debug-level option (-D)
224 @cindex ntpd-set-debug-level
226 This is the ``set the output debug message level'' option.
228 This option has some usage constraints. It:
231 may appear an unlimited number of times.
233 must be compiled in by defining @code{DEBUG} during the compilation.
236 Set the output debugging level. Can be supplied multiple times,
237 but each overrides the previous value(s).
240 @subsection driftfile option (-f)
241 @cindex ntpd-driftfile
243 This is the ``frequency drift file name'' option.
244 The name and path of the frequency file,
247 This is the same operation as the
249 configuration specification in the
254 @subsection panicgate option (-g)
255 @cindex ntpd-panicgate
257 This is the ``allow the first adjustment to be big'' option.
260 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,
262 will exit with a message to the system log. This option can be used with the
269 configuration file directive for other options.
272 @subsection jaildir option (-i)
275 This is the ``jail directory'' option.
276 Chroot the server to the directory
279 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.
280 You may need to also specify a
285 @subsection interface option (-I)
286 @cindex ntpd-interface
288 This is the ``listen on interface'' option.
290 This option has some usage constraints. It:
293 may appear an unlimited number of times.
299 @subsection keyfile option (-k)
302 This is the ``path to symmetric keys'' option.
303 Specify the name and path of the symmetric key file.
306 This is the same operation as the
308 configuration file directive.
311 @subsection logfile option (-l)
314 This is the ``path to the log file'' option.
315 Specify the name and path of the log file.
316 The default is the system log file.
317 This is the same operation as the
319 configuration file directive.
321 @node ntpd novirtualips
322 @subsection novirtualips option (-L)
323 @cindex ntpd-novirtualips
325 This is the ``do not listen to virtual ips'' option.
326 Do not listen to virtual IPs. The default is to listen.
328 @node ntpd modifymmtimer
329 @subsection modifymmtimer option (-M)
330 @cindex ntpd-modifymmtimer
332 This is the ``modify multimedia timer (windows only)'' option.
334 This option has some usage constraints. It:
337 must be compiled in by defining @code{SYS_WINNT} during the compilation.
340 Set the Windows Multimedia Timer to highest resolution.
343 @subsection nofork option (-n)
346 This is the ``do not fork'' option.
350 @subsection nice option (-N)
353 This is the ``run at high priority'' option.
354 To the extent permitted by the operating system, run
356 at the highest priority.
359 @subsection pidfile option (-p)
362 This is the ``path to the pid file'' option.
363 Specify the name and path of the file used to record
366 This is the same operation as the
368 configuration file directive.
371 @subsection priority option (-P)
372 @cindex ntpd-priority
374 This is the ``process priority'' option.
375 To the extent permitted by the operating system, run
378 sched_setscheduler(SCHED_FIFO)
382 @subsection quit option (-q)
385 This is the ``set the time and quit'' option.
387 will exit just after the first time the clock is set. This behavior mimics that of the
389 program, which is to be retired.
394 options can be used with this option.
395 Note: The kernel time discipline is disabled with this option.
397 @node ntpd propagationdelay
398 @subsection propagationdelay option (-r)
399 @cindex ntpd-propagationdelay
401 This is the ``broadcast/propagation delay'' option.
402 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.
404 @node ntpd updateinterval
405 @subsection updateinterval option (-U)
406 @cindex ntpd-updateinterval
408 This is the ``interval in seconds between scans for new or dropped interfaces'' option.
409 Give the time in seconds between two scans for new or dropped interfaces.
410 For systems with routing socket support the scans will be performed shortly after the interface change
411 has been detected by the system.
412 Use 0 to disable scanning.
415 @subsection statsdir option (-s)
416 @cindex ntpd-statsdir
418 This is the ``statistics file location'' option.
419 Specify the directory path for files created by the statistics facility.
420 This is the same operation as the
422 configuration file directive.
424 @node ntpd trustedkey
425 @subsection trustedkey option (-t)
426 @cindex ntpd-trustedkey
428 This is the ``trusted key number'' option.
430 This option has some usage constraints. It:
433 may appear an unlimited number of times.
436 Add a key number to the trusted key list.
439 @subsection user option (-u)
442 This is the ``run as userid (or userid:groupid)'' option.
443 Specify a user, and optionally a group, to switch to.
444 This option is only available if the OS supports to run the server without full root privileges.
445 Currently, this option is supported under NetBSD (configure with
447 ) and Linux (configure with
452 @subsection var option (-v)
455 This is the ``make arg an ntp variable (rw)'' option.
457 This option has some usage constraints. It:
460 may appear an unlimited number of times.
466 @subsection dvar option (-V)
469 This is the ``make arg an ntp variable (rw|def)'' option.
471 This option has some usage constraints. It:
474 may appear an unlimited number of times.
480 @subsection slew option (-x)
483 This is the ``slew up to 600 seconds'' option.
484 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.
485 This option sets the threshold to 600 s, which is well within the accuracy window to set the clock manually.
486 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.
487 Thus, an adjustment as much as 600 s will take almost 14 days to complete.
488 This option can be used with the
495 configuration file directive for other options.
496 Note: The kernel time discipline is disabled with this option.