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22275970Scy<h1 class="settitle">ntpd: Network Time Protocol (NTP) Daemon User's Manual</h1>
23275970Scy<div class="node">
24275970Scy<p><hr>
25275970Scy<a name="Top"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-Description">ntpd Description</a>,
26275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#dir">(dir)</a>,
27275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#dir">(dir)</a>
28275970Scy<br>
29275970Scy</div>
30275970Scy
31275970Scy<h2 class="unnumbered">ntpd: Network Time Protocol (NTP) Daemon User Manual</h2>
32275970Scy
33275970Scy<p>The <code>ntpd</code> program is an operating system daemon that synchronizes the
34275970Scysystem clock to remote NTP time servers or local reference clocks. 
35275970ScyIt is a complete implementation of NTP version 4 defined by RFC-5905, but
36275970Scyalso retains compatible with version 3 defined by RFC-1305 and versions
37275970Scy1 and 2, defined by RFC-1059 and RFC-1119, respectively. 
38275970ScyThe program can operate in any of several modes, including client/server,
39275970Scysymmetric and broadcast modes, and with both symmetric-key and public-key
40275970Scycryptography.
41275970Scy
42275970Scy  <p>This document applies to version 4.2.8 of <code>ntpd</code>.
43275970Scy
44275970Scy<ul class="menu">
45275970Scy<li><a accesskey="1" href="#ntpd-Description">ntpd Description</a>:             Description
46275970Scy<li><a accesskey="2" href="#ntpd-Invocation">ntpd Invocation</a>: 		Invoking ntpd
47275970Scy<li><a accesskey="3" href="#Usage">Usage</a>:                        Usage
48275970Scy</ul>
49275970Scy
50275970Scy<div class="node">
51275970Scy<p><hr>
52275970Scy<a name="ntpd-Description"></a>
53275970Scy<br>
54275970Scy</div>
55275970Scy
56275970Scy<!-- node-name,  next,  previous,  up -->
57275970Scy<h3 class="section">Description</h3>
58275970Scy
59275970Scy<p>The <code>ntpd</code> program ordinarily requires
60275970Scya configuration file described at <a href="#ntp_002econf">ntp.conf</a>. 
61275970ScyThis configuration file contains configuration commands described on
62275970Scythe pages listed above. 
63275970ScyHowever a client can discover remote servers and configure them
64275970Scyautomatically. 
65275970ScyThis makes it possible to deploy a fleet of workstations without
66275970Scyspecifying configuration details specific to the local environment.
67275970Scy
68275970Scy  <p>The <code>ntpd</code> program normally operates continuously while adjusting the
69275970Scysystem time and frequency, but in some cases this might not be
70275970Scypractical. 
71275970ScyWith the <code>-q</code> option <code>ntpd</code> operates as in continuous mode, but
72275970Scyexits just after setting the clock for the first time. 
73275970ScyMost applications will probably want to specify the <code>iburst</code>
74275970Scyoption with the <code>server</code> command. 
75275970ScyWith this option an initial volley of messages is exchanged to
76275970Scygroom the data and set the clock in about ten seconds' time. 
77275970ScyIf nothing is heard after a few minutes' time,
78275970Scythe daemon times out and exits without setting the clock.
79275970Scy
80275970Scy<div class="node">
81275970Scy<p><hr>
82275970Scy<a name="ntpd-Invocation"></a>
83275970Scy<br>
84275970Scy</div>
85275970Scy
86275970Scy<h3 class="section">Invoking ntpd</h3>
87275970Scy
88275970Scy<p><a name="index-ntpd-1"></a><a name="index-NTP-daemon-program-2"></a>
89275970Scy
90275970Scy  <p>The
91275970Scy<code>ntpd</code>
92275970Scyutility is an operating system daemon which sets
93275970Scyand maintains the system time of day in synchronism with Internet
94275970Scystandard time servers. 
95275970ScyIt is a complete implementation of the
96275970ScyNetwork Time Protocol (NTP) version 4, as defined by RFC-5905,
97275970Scybut also retains compatibility with
98275970Scyversion 3, as defined by RFC-1305, and versions 1
99275970Scyand 2, as defined by RFC-1059 and RFC-1119, respectively.
100275970Scy
101275970Scy  <p>The
102275970Scy<code>ntpd</code>
103275970Scyutility does most computations in 64-bit floating point
104275970Scyarithmetic and does relatively clumsy 64-bit fixed point operations
105275970Scyonly when necessary to preserve the ultimate precision, about 232
106275970Scypicoseconds. 
107275970ScyWhile the ultimate precision is not achievable with
108275970Scyordinary workstations and networks of today, it may be required
109275970Scywith future gigahertz CPU clocks and gigabit LANs.
110275970Scy
111275970Scy  <p>Ordinarily,
112275970Scy<code>ntpd</code>
113275970Scyreads the
114275970Scy<code>ntp.conf(5)</code>
115275970Scyconfiguration file at startup time in order to determine the
116275970Scysynchronization sources and operating modes. 
117275970ScyIt is also possible to
118275970Scyspecify a working, although limited, configuration entirely on the
119275970Scycommand line, obviating the need for a configuration file. 
120275970ScyThis may
121275970Scybe particularly useful when the local host is to be configured as a
122275970Scybroadcast/multicast client, with all peers being determined by
123275970Scylistening to broadcasts at run time.
124275970Scy
125275970Scy  <p>If NetInfo support is built into
126275970Scy<code>ntpd</code>
127275970Scythen
128275970Scy<code>ntpd</code>
129275970Scywill attempt to read its configuration from the
130275970ScyNetInfo if the default
131275970Scy<code>ntp.conf(5)</code>
132275970Scyfile cannot be read and no file is
133275970Scyspecified by the
134275970Scy<code>-c</code>
135275970Scyoption.
136275970Scy
137275970Scy  <p>Various internal
138275970Scy<code>ntpd</code>
139275970Scyvariables can be displayed and
140275970Scyconfiguration options altered while the
141275970Scy<code>ntpd</code>
142275970Scyis running
143275970Scyusing the
144275970Scy<code>ntpq(1ntpqmdoc)</code>
145275970Scyand
146275970Scy<code>ntpdc(1ntpdcmdoc)</code>
147275970Scyutility programs.
148275970Scy
149275970Scy  <p>When
150275970Scy<code>ntpd</code>
151275970Scystarts it looks at the value of
152275970Scy<code>umask(2)</code>,
153275970Scyand if zero
154275970Scy<code>ntpd</code>
155275970Scywill set the
156275970Scy<code>umask(2)</code>
157275970Scyto 022.
158275970Scy
159275970Scy  <p>This section was generated by <strong>AutoGen</strong>,
160275970Scyusing the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntpd</code> program. 
161275970ScyThis software is released under the NTP license, &lt;http://ntp.org/license>;.
162275970Scy
163275970Scy<ul class="menu">
164275970Scy<li><a accesskey="1" href="#ntpd-usage">ntpd usage</a>:                   ntpd help/usage (<span class="option">--help</span>)
165275970Scy<li><a accesskey="2" href="#ntpd-ipv4">ntpd ipv4</a>:                    ipv4 option (-4)
166275970Scy<li><a accesskey="3" href="#ntpd-ipv6">ntpd ipv6</a>:                    ipv6 option (-6)
167275970Scy<li><a accesskey="4" href="#ntpd-authreq">ntpd authreq</a>:                 authreq option (-a)
168275970Scy<li><a accesskey="5" href="#ntpd-authnoreq">ntpd authnoreq</a>:               authnoreq option (-A)
169275970Scy<li><a accesskey="6" href="#ntpd-configfile">ntpd configfile</a>:              configfile option (-c)
170275970Scy<li><a accesskey="7" href="#ntpd-driftfile">ntpd driftfile</a>:               driftfile option (-f)
171275970Scy<li><a accesskey="8" href="#ntpd-panicgate">ntpd panicgate</a>:               panicgate option (-g)
172275970Scy<li><a accesskey="9" href="#ntpd-jaildir">ntpd jaildir</a>:                 jaildir option (-i)
173275970Scy<li><a href="#ntpd-interface">ntpd interface</a>:               interface option (-I)
174275970Scy<li><a href="#ntpd-keyfile">ntpd keyfile</a>:                 keyfile option (-k)
175275970Scy<li><a href="#ntpd-logfile">ntpd logfile</a>:                 logfile option (-l)
176275970Scy<li><a href="#ntpd-novirtualips">ntpd novirtualips</a>:            novirtualips option (-L)
177275970Scy<li><a href="#ntpd-modifymmtimer">ntpd modifymmtimer</a>:           modifymmtimer option (-M)
178275970Scy<li><a href="#ntpd-nice">ntpd nice</a>:                    nice option (-N)
179275970Scy<li><a href="#ntpd-pidfile">ntpd pidfile</a>:                 pidfile option (-p)
180275970Scy<li><a href="#ntpd-priority">ntpd priority</a>:                priority option (-P)
181275970Scy<li><a href="#ntpd-quit">ntpd quit</a>:                    quit option (-q)
182275970Scy<li><a href="#ntpd-propagationdelay">ntpd propagationdelay</a>:        propagationdelay option (-r)
183275970Scy<li><a href="#ntpd-saveconfigquit">ntpd saveconfigquit</a>:          saveconfigquit option
184275970Scy<li><a href="#ntpd-statsdir">ntpd statsdir</a>:                statsdir option (-s)
185275970Scy<li><a href="#ntpd-trustedkey">ntpd trustedkey</a>:              trustedkey option (-t)
186275970Scy<li><a href="#ntpd-user">ntpd user</a>:                    user option (-u)
187275970Scy<li><a href="#ntpd-updateinterval">ntpd updateinterval</a>:          updateinterval option (-U)
188275970Scy<li><a href="#ntpd-wait_002dsync">ntpd wait-sync</a>:               wait-sync option (-w)
189275970Scy<li><a href="#ntpd-slew">ntpd slew</a>:                    slew option (-x)
190275970Scy<li><a href="#ntpd-usepcc">ntpd usepcc</a>:                  usepcc option
191275970Scy<li><a href="#ntpd-pccfreq">ntpd pccfreq</a>:                 pccfreq option
192275970Scy<li><a href="#ntpd-mdns">ntpd mdns</a>:                    mdns option (-m)
193275970Scy<li><a href="#ntpd-config">ntpd config</a>:                  presetting/configuring ntpd
194275970Scy<li><a href="#ntpd-exit-status">ntpd exit status</a>:             exit status
195275970Scy<li><a href="#ntpd-Usage">ntpd Usage</a>:                   Usage
196275970Scy<li><a href="#ntpd-Files">ntpd Files</a>:                   Files
197275970Scy<li><a href="#ntpd-See-Also">ntpd See Also</a>:                See Also
198275970Scy<li><a href="#ntpd-Bugs">ntpd Bugs</a>:                    Bugs
199275970Scy<li><a href="#ntpd-Notes">ntpd Notes</a>:                   Notes
200275970Scy</ul>
201275970Scy
202275970Scy<div class="node">
203275970Scy<p><hr>
204275970Scy<a name="ntpd-usage"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-ipv4">ntpd ipv4</a>,
205275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
206275970Scy<br>
207275970Scy</div>
208275970Scy
209275970Scy<h4 class="subsection">ntpd help/usage (<span class="option">--help</span>)</h4>
210275970Scy
211275970Scy<p><a name="index-ntpd-help-3"></a>
212275970ScyThis is the automatically generated usage text for ntpd.
213275970Scy
214275970Scy  <p>The text printed is the same whether selected with the <code>help</code> option
215275970Scy(<span class="option">--help</span>) or the <code>more-help</code> option (<span class="option">--more-help</span>).  <code>more-help</code> will print
216275970Scythe usage text by passing it through a pager program. 
217275970Scy<code>more-help</code> is disabled on platforms without a working
218275970Scy<code>fork(2)</code> function.  The <code>PAGER</code> environment variable is
219275970Scyused to select the program, defaulting to <span class="file">more</span>.  Both will exit
220275970Scywith a status code of 0.
221275970Scy
222275970Scy<pre class="example">ntpd - NTP daemon program - Ver. 4.2.8-x
223275970ScyUsage:  ntpd [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... \
224275970Scy                [ &lt;server1&gt; ... &lt;serverN&gt; ]
225275970Scy  Flg Arg Option-Name    Description
226275970Scy   -4 no  ipv4           Force IPv4 DNS name resolution
227275970Scy                                - prohibits the option 'ipv6'
228275970Scy   -6 no  ipv6           Force IPv6 DNS name resolution
229275970Scy                                - prohibits the option 'ipv4'
230275970Scy   -a no  authreq        Require crypto authentication
231275970Scy                                - prohibits the option 'authnoreq'
232275970Scy   -A no  authnoreq      Do not require crypto authentication
233275970Scy                                - prohibits the option 'authreq'
234275970Scy   -b no  bcastsync      Allow us to sync to broadcast servers
235275970Scy   -c Str configfile     configuration file name
236275970Scy   -d no  debug-level    Increase debug verbosity level
237275970Scy                                - may appear multiple times
238275970Scy   -D Num set-debug-level Set the debug verbosity level
239275970Scy                                - may appear multiple times
240275970Scy   -f Str driftfile      frequency drift file name
241275970Scy   -g no  panicgate      Allow the first adjustment to be Big
242275970Scy                                - may appear multiple times
243275970Scy   -i Str jaildir        Jail directory
244275970Scy   -I Str interface      Listen on an interface name or address
245275970Scy                                - may appear multiple times
246275970Scy   -k Str keyfile        path to symmetric keys
247275970Scy   -l Str logfile        path to the log file
248275970Scy   -L no  novirtualips   Do not listen to virtual interfaces
249275970Scy   -n no  nofork         Do not fork
250275970Scy                                - prohibits the option 'wait-sync'
251275970Scy   -N no  nice           Run at high priority
252275970Scy   -p Str pidfile        path to the PID file
253275970Scy   -P Num priority       Process priority
254275970Scy   -q no  quit           Set the time and quit
255275970Scy                                - prohibits these options:
256275970Scy                                saveconfigquit
257275970Scy                                wait-sync
258275970Scy   -r Str propagationdelay Broadcast/propagation delay
259275970Scy      Str saveconfigquit Save parsed configuration and quit
260275970Scy                                - prohibits these options:
261275970Scy                                quit
262275970Scy                                wait-sync
263275970Scy   -s Str statsdir       Statistics file location
264275970Scy   -t Str trustedkey     Trusted key number
265275970Scy                                - may appear multiple times
266275970Scy   -u Str user           Run as userid (or userid:groupid)
267275970Scy   -U Num updateinterval interval in seconds between scans for new or dropped interfaces
268275970Scy      Str var            make ARG an ntp variable (RW)
269275970Scy                                - may appear multiple times
270275970Scy      Str dvar           make ARG an ntp variable (RW|DEF)
271275970Scy                                - may appear multiple times
272275970Scy   -w Num wait-sync      Seconds to wait for first clock sync
273275970Scy                                - prohibits these options:
274275970Scy                                nofork
275275970Scy                                quit
276275970Scy                                saveconfigquit
277275970Scy   -x no  slew           Slew up to 600 seconds
278275970Scy      opt version        output version information and exit
279275970Scy   -? no  help           display extended usage information and exit
280275970Scy   -! no  more-help      extended usage information passed thru pager
281275970Scy
282275970ScyOptions are specified by doubled hyphens and their name or by a single
283275970Scyhyphen and the flag character.
284275970Scy
285275970Scy
286275970ScyThe following option preset mechanisms are supported:
287275970Scy - examining environment variables named NTPD_*
288275970Scy
289275970ScyPlease send bug reports to:  &lt;http://bugs.ntp.org, bugs@ntp.org&gt;
290275970Scy</pre>
291275970Scy  <div class="node">
292275970Scy<p><hr>
293275970Scy<a name="ntpd-ipv4"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-ipv6">ntpd ipv6</a>,
294275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-usage">ntpd usage</a>,
295275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
296275970Scy<br>
297275970Scy</div>
298275970Scy
299275970Scy<h4 class="subsection">ipv4 option (-4)</h4>
300275970Scy
301275970Scy<p><a name="index-ntpd_002dipv4-4"></a>
302275970ScyThis is the &ldquo;force ipv4 dns name resolution&rdquo; option.
303275970Scy
304275970Scy<p class="noindent">This option has some usage constraints.  It:
305275970Scy     <ul>
306275970Scy<li>must not appear in combination with any of the following options:
307275970Scyipv6. 
308275970Scy</ul>
309275970Scy
310275970Scy  <p>Force DNS resolution of following host names on the command line
311275970Scyto the IPv4 namespace. 
312275970Scy<div class="node">
313275970Scy<p><hr>
314275970Scy<a name="ntpd-ipv6"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-authreq">ntpd authreq</a>,
315275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-ipv4">ntpd ipv4</a>,
316275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
317275970Scy<br>
318275970Scy</div>
319275970Scy
320275970Scy<h4 class="subsection">ipv6 option (-6)</h4>
321275970Scy
322275970Scy<p><a name="index-ntpd_002dipv6-5"></a>
323275970ScyThis is the &ldquo;force ipv6 dns name resolution&rdquo; option.
324275970Scy
325275970Scy<p class="noindent">This option has some usage constraints.  It:
326275970Scy     <ul>
327275970Scy<li>must not appear in combination with any of the following options:
328275970Scyipv4. 
329275970Scy</ul>
330275970Scy
331275970Scy  <p>Force DNS resolution of following host names on the command line
332275970Scyto the IPv6 namespace. 
333275970Scy<div class="node">
334275970Scy<p><hr>
335275970Scy<a name="ntpd-authreq"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-authnoreq">ntpd authnoreq</a>,
336275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-ipv6">ntpd ipv6</a>,
337275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
338275970Scy<br>
339275970Scy</div>
340275970Scy
341275970Scy<h4 class="subsection">authreq option (-a)</h4>
342275970Scy
343275970Scy<p><a name="index-ntpd_002dauthreq-6"></a>
344275970ScyThis is the &ldquo;require crypto authentication&rdquo; option.
345275970Scy
346275970Scy<p class="noindent">This option has some usage constraints.  It:
347275970Scy     <ul>
348275970Scy<li>must not appear in combination with any of the following options:
349275970Scyauthnoreq. 
350275970Scy</ul>
351275970Scy
352275970Scy  <p>Require cryptographic authentication for broadcast client,
353275970Scymulticast client and symmetric passive associations. 
354275970ScyThis is the default. 
355275970Scy<div class="node">
356275970Scy<p><hr>
357275970Scy<a name="ntpd-authnoreq"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-configfile">ntpd configfile</a>,
358275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-authreq">ntpd authreq</a>,
359275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
360275970Scy<br>
361275970Scy</div>
362275970Scy
363275970Scy<h4 class="subsection">authnoreq option (-A)</h4>
364275970Scy
365275970Scy<p><a name="index-ntpd_002dauthnoreq-7"></a>
366275970ScyThis is the &ldquo;do not require crypto authentication&rdquo; option.
367275970Scy
368275970Scy<p class="noindent">This option has some usage constraints.  It:
369275970Scy     <ul>
370275970Scy<li>must not appear in combination with any of the following options:
371275970Scyauthreq. 
372275970Scy</ul>
373275970Scy
374275970Scy  <p>Do not require cryptographic authentication for broadcast client,
375275970Scymulticast client and symmetric passive associations. 
376275970ScyThis is almost never a good idea. 
377275970Scy<div class="node">
378275970Scy<p><hr>
379275970Scy<a name="ntpd-configfile"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-driftfile">ntpd driftfile</a>,
380275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-authnoreq">ntpd authnoreq</a>,
381275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
382275970Scy<br>
383275970Scy</div>
384275970Scy
385275970Scy<h4 class="subsection">configfile option (-c)</h4>
386275970Scy
387275970Scy<p><a name="index-ntpd_002dconfigfile-8"></a>
388275970ScyThis is the &ldquo;configuration file name&rdquo; option. 
389275970ScyThis option takes a string argument. 
390275970ScyThe name and path of the configuration file,
391275970Scy<span class="file">/etc/ntp.conf</span>
392275970Scyby default. 
393275970Scy<div class="node">
394275970Scy<p><hr>
395275970Scy<a name="ntpd-driftfile"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-panicgate">ntpd panicgate</a>,
396275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-configfile">ntpd configfile</a>,
397275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
398275970Scy<br>
399275970Scy</div>
400275970Scy
401275970Scy<h4 class="subsection">driftfile option (-f)</h4>
402275970Scy
403275970Scy<p><a name="index-ntpd_002ddriftfile-9"></a>
404275970ScyThis is the &ldquo;frequency drift file name&rdquo; option. 
405275970ScyThis option takes a string argument. 
406275970ScyThe name and path of the frequency file,
407275970Scy<span class="file">/etc/ntp.drift</span>
408275970Scyby default. 
409275970ScyThis is the same operation as the
410275970Scy<code>driftfile</code> <kbd>driftfile</kbd>
411275970Scyconfiguration specification in the
412275970Scy<span class="file">/etc/ntp.conf</span>
413275970Scyfile. 
414275970Scy<div class="node">
415275970Scy<p><hr>
416275970Scy<a name="ntpd-panicgate"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-jaildir">ntpd jaildir</a>,
417275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-driftfile">ntpd driftfile</a>,
418275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
419275970Scy<br>
420275970Scy</div>
421275970Scy
422275970Scy<h4 class="subsection">panicgate option (-g)</h4>
423275970Scy
424275970Scy<p><a name="index-ntpd_002dpanicgate-10"></a>
425275970ScyThis is the &ldquo;allow the first adjustment to be big&rdquo; option.
426275970Scy
427275970Scy<p class="noindent">This option has some usage constraints.  It:
428275970Scy     <ul>
429275970Scy<li>may appear an unlimited number of times. 
430275970Scy</ul>
431275970Scy
432275970Scy  <p>Normally,
433275970Scy<code>ntpd</code>
434275970Scyexits 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,
435275970Scy<code>ntpd</code>
436275970Scywill exit with a message to the system log. This option can be used with the
437275970Scy<code>-q</code>
438275970Scyand
439275970Scy<code>-x</code>
440275970Scyoptions. 
441275970ScySee the
442275970Scy<code>tinker</code>
443275970Scyconfiguration file directive for other options. 
444275970Scy<div class="node">
445275970Scy<p><hr>
446275970Scy<a name="ntpd-jaildir"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-interface">ntpd interface</a>,
447275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-panicgate">ntpd panicgate</a>,
448275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
449275970Scy<br>
450275970Scy</div>
451275970Scy
452275970Scy<h4 class="subsection">jaildir option (-i)</h4>
453275970Scy
454275970Scy<p><a name="index-ntpd_002djaildir-11"></a>
455275970ScyThis is the &ldquo;jail directory&rdquo; option. 
456275970ScyThis option takes a string argument.
457275970Scy
458275970Scy<p class="noindent">This option has some usage constraints.  It:
459275970Scy     <ul>
460275970Scy<li>must be compiled in by defining <code>HAVE_DROPROOT</code> during the compilation. 
461275970Scy</ul>
462275970Scy
463275970Scy  <p>Chroot the server to the directory
464275970Scy<kbd>jaildir</kbd>
465275970Scy. 
466275970ScyThis option also implies that the server attempts to drop root privileges at startup. 
467275970ScyYou may need to also specify a
468275970Scy<code>-u</code>
469275970Scyoption. 
470275970ScyThis option is only available if the OS supports adjusting the clock
471275970Scywithout full root privileges. 
472275970ScyThis option is supported under NetBSD (configure with
473275970Scy<code>--enable-clockctl</code>) or Linux (configure with
474275970Scy<code>--enable-linuxcaps</code>) or Solaris (configure with <code>--enable-solarisprivs</code>). 
475275970Scy<div class="node">
476275970Scy<p><hr>
477275970Scy<a name="ntpd-interface"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-keyfile">ntpd keyfile</a>,
478275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-jaildir">ntpd jaildir</a>,
479275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
480275970Scy<br>
481275970Scy</div>
482275970Scy
483275970Scy<h4 class="subsection">interface option (-I)</h4>
484275970Scy
485275970Scy<p><a name="index-ntpd_002dinterface-12"></a>
486275970ScyThis is the &ldquo;listen on an interface name or address&rdquo; option. 
487275970ScyThis option takes a string argument <span class="file">iface</span>.
488275970Scy
489275970Scy<p class="noindent">This option has some usage constraints.  It:
490275970Scy     <ul>
491275970Scy<li>may appear an unlimited number of times. 
492275970Scy</ul>
493275970Scy
494275970Scy  <p>Open the network address given, or all the addresses associated with the
495275970Scygiven interface name.  This option may appear multiple times.  This option
496275970Scyalso implies not opening other addresses, except wildcard and localhost. 
497275970ScyThis option is deprecated. Please consider using the configuration file
498275970Scy<code>interface</code> command, which is more versatile. 
499275970Scy<div class="node">
500275970Scy<p><hr>
501275970Scy<a name="ntpd-keyfile"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-logfile">ntpd logfile</a>,
502275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-interface">ntpd interface</a>,
503275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
504275970Scy<br>
505275970Scy</div>
506275970Scy
507275970Scy<h4 class="subsection">keyfile option (-k)</h4>
508275970Scy
509275970Scy<p><a name="index-ntpd_002dkeyfile-13"></a>
510275970ScyThis is the &ldquo;path to symmetric keys&rdquo; option. 
511275970ScyThis option takes a string argument. 
512275970ScySpecify the name and path of the symmetric key file. 
513275970Scy<span class="file">/etc/ntp.keys</span>
514275970Scyis the default. 
515275970ScyThis is the same operation as the
516275970Scy<code>keys</code> <kbd>keyfile</kbd>
517275970Scyconfiguration file directive. 
518275970Scy<div class="node">
519275970Scy<p><hr>
520275970Scy<a name="ntpd-logfile"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-novirtualips">ntpd novirtualips</a>,
521275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-keyfile">ntpd keyfile</a>,
522275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
523275970Scy<br>
524275970Scy</div>
525275970Scy
526275970Scy<h4 class="subsection">logfile option (-l)</h4>
527275970Scy
528275970Scy<p><a name="index-ntpd_002dlogfile-14"></a>
529275970ScyThis is the &ldquo;path to the log file&rdquo; option. 
530275970ScyThis option takes a string argument. 
531275970ScySpecify the name and path of the log file. 
532275970ScyThe default is the system log file. 
533275970ScyThis is the same operation as the
534275970Scy<code>logfile</code> <kbd>logfile</kbd>
535275970Scyconfiguration file directive. 
536275970Scy<div class="node">
537275970Scy<p><hr>
538275970Scy<a name="ntpd-novirtualips"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-modifymmtimer">ntpd modifymmtimer</a>,
539275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-logfile">ntpd logfile</a>,
540275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
541275970Scy<br>
542275970Scy</div>
543275970Scy
544275970Scy<h4 class="subsection">novirtualips option (-L)</h4>
545275970Scy
546275970Scy<p><a name="index-ntpd_002dnovirtualips-15"></a>
547275970ScyThis is the &ldquo;do not listen to virtual interfaces&rdquo; option. 
548275970ScyDo not listen to virtual interfaces, defined as those with
549275970Scynames containing a colon.  This option is deprecated.  Please
550275970Scyconsider using the configuration file <code>interface</code> command, which
551275970Scyis more versatile. 
552275970Scy<div class="node">
553275970Scy<p><hr>
554275970Scy<a name="ntpd-modifymmtimer"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-nice">ntpd nice</a>,
555275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-novirtualips">ntpd novirtualips</a>,
556275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
557275970Scy<br>
558275970Scy</div>
559275970Scy
560275970Scy<h4 class="subsection">modifymmtimer option (-M)</h4>
561275970Scy
562275970Scy<p><a name="index-ntpd_002dmodifymmtimer-16"></a>
563275970ScyThis is the &ldquo;modify multimedia timer (windows only)&rdquo; option.
564275970Scy
565275970Scy<p class="noindent">This option has some usage constraints.  It:
566275970Scy     <ul>
567275970Scy<li>must be compiled in by defining <code>SYS_WINNT</code> during the compilation. 
568275970Scy</ul>
569275970Scy
570275970Scy  <p>Set the Windows Multimedia Timer to highest resolution.  This
571275970Scyensures the resolution does not change while ntpd is running,
572275970Scyavoiding timekeeping glitches associated with changes. 
573275970Scy<div class="node">
574275970Scy<p><hr>
575275970Scy<a name="ntpd-nice"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-pidfile">ntpd pidfile</a>,
576275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-modifymmtimer">ntpd modifymmtimer</a>,
577275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
578275970Scy<br>
579275970Scy</div>
580275970Scy
581275970Scy<h4 class="subsection">nice option (-N)</h4>
582275970Scy
583275970Scy<p><a name="index-ntpd_002dnice-17"></a>
584275970ScyThis is the &ldquo;run at high priority&rdquo; option. 
585275970ScyTo the extent permitted by the operating system, run
586275970Scy<code>ntpd</code>
587275970Scyat the highest priority. 
588275970Scy<div class="node">
589275970Scy<p><hr>
590275970Scy<a name="ntpd-pidfile"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-priority">ntpd priority</a>,
591275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-nice">ntpd nice</a>,
592275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
593275970Scy<br>
594275970Scy</div>
595275970Scy
596275970Scy<h4 class="subsection">pidfile option (-p)</h4>
597275970Scy
598275970Scy<p><a name="index-ntpd_002dpidfile-18"></a>
599275970ScyThis is the &ldquo;path to the pid file&rdquo; option. 
600275970ScyThis option takes a string argument. 
601275970ScySpecify the name and path of the file used to record
602275970Scy<code>ntpd</code>'s
603275970Scyprocess ID. 
604275970ScyThis is the same operation as the
605275970Scy<code>pidfile</code> <kbd>pidfile</kbd>
606275970Scyconfiguration file directive. 
607275970Scy<div class="node">
608275970Scy<p><hr>
609275970Scy<a name="ntpd-priority"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-quit">ntpd quit</a>,
610275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-pidfile">ntpd pidfile</a>,
611275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
612275970Scy<br>
613275970Scy</div>
614275970Scy
615275970Scy<h4 class="subsection">priority option (-P)</h4>
616275970Scy
617275970Scy<p><a name="index-ntpd_002dpriority-19"></a>
618275970ScyThis is the &ldquo;process priority&rdquo; option. 
619275970ScyThis option takes a number argument. 
620275970ScyTo the extent permitted by the operating system, run
621275970Scy<code>ntpd</code>
622275970Scyat the specified
623275970Scy<code>sched_setscheduler(SCHED_FIFO)</code>
624275970Scypriority. 
625275970Scy<div class="node">
626275970Scy<p><hr>
627275970Scy<a name="ntpd-quit"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-propagationdelay">ntpd propagationdelay</a>,
628275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-priority">ntpd priority</a>,
629275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
630275970Scy<br>
631275970Scy</div>
632275970Scy
633275970Scy<h4 class="subsection">quit option (-q)</h4>
634275970Scy
635275970Scy<p><a name="index-ntpd_002dquit-20"></a>
636275970ScyThis is the &ldquo;set the time and quit&rdquo; option.
637275970Scy
638275970Scy<p class="noindent">This option has some usage constraints.  It:
639275970Scy     <ul>
640275970Scy<li>must not appear in combination with any of the following options:
641275970Scysaveconfigquit, wait-sync. 
642275970Scy</ul>
643275970Scy
644275970Scy  <p><code>ntpd</code>
645275970Scywill not daemonize and will exit after the clock is first
646275970Scysynchronized.  This behavior mimics that of the
647275970Scy<code>ntpdate</code>
648275970Scyprogram, which will soon be replaced with a shell script. 
649275970ScyThe
650275970Scy<code>-g</code>
651275970Scyand
652275970Scy<code>-x</code>
653275970Scyoptions can be used with this option. 
654275970ScyNote: The kernel time discipline is disabled with this option. 
655275970Scy<div class="node">
656275970Scy<p><hr>
657275970Scy<a name="ntpd-propagationdelay"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-saveconfigquit">ntpd saveconfigquit</a>,
658275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-quit">ntpd quit</a>,
659275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
660275970Scy<br>
661275970Scy</div>
662275970Scy
663275970Scy<h4 class="subsection">propagationdelay option (-r)</h4>
664275970Scy
665275970Scy<p><a name="index-ntpd_002dpropagationdelay-21"></a>
666275970ScyThis is the &ldquo;broadcast/propagation delay&rdquo; option. 
667275970ScyThis option takes a string argument. 
668275970ScySpecify 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. 
669275970Scy<div class="node">
670275970Scy<p><hr>
671275970Scy<a name="ntpd-saveconfigquit"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-statsdir">ntpd statsdir</a>,
672275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-propagationdelay">ntpd propagationdelay</a>,
673275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
674275970Scy<br>
675275970Scy</div>
676275970Scy
677275970Scy<h4 class="subsection">saveconfigquit option</h4>
678275970Scy
679275970Scy<p><a name="index-ntpd_002dsaveconfigquit-22"></a>
680275970ScyThis is the &ldquo;save parsed configuration and quit&rdquo; option. 
681275970ScyThis option takes a string argument.
682275970Scy
683275970Scy<p class="noindent">This option has some usage constraints.  It:
684275970Scy     <ul>
685275970Scy<li>must be compiled in by defining <code>SAVECONFIG</code> during the compilation. 
686275970Scy<li>must not appear in combination with any of the following options:
687275970Scyquit, wait-sync. 
688275970Scy</ul>
689275970Scy
690275970Scy  <p>Cause <code>ntpd</code> to parse its startup configuration file and save an
691275970Scyequivalent to the given filename and exit.  This option was
692275970Scydesigned for automated testing. 
693275970Scy<div class="node">
694275970Scy<p><hr>
695275970Scy<a name="ntpd-statsdir"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-trustedkey">ntpd trustedkey</a>,
696275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-saveconfigquit">ntpd saveconfigquit</a>,
697275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
698275970Scy<br>
699275970Scy</div>
700275970Scy
701275970Scy<h4 class="subsection">statsdir option (-s)</h4>
702275970Scy
703275970Scy<p><a name="index-ntpd_002dstatsdir-23"></a>
704275970ScyThis is the &ldquo;statistics file location&rdquo; option. 
705275970ScyThis option takes a string argument. 
706275970ScySpecify the directory path for files created by the statistics facility. 
707275970ScyThis is the same operation as the
708275970Scy<code>statsdir</code> <kbd>statsdir</kbd>
709275970Scyconfiguration file directive. 
710275970Scy<div class="node">
711275970Scy<p><hr>
712275970Scy<a name="ntpd-trustedkey"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-user">ntpd user</a>,
713275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-statsdir">ntpd statsdir</a>,
714275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
715275970Scy<br>
716275970Scy</div>
717275970Scy
718275970Scy<h4 class="subsection">trustedkey option (-t)</h4>
719275970Scy
720275970Scy<p><a name="index-ntpd_002dtrustedkey-24"></a>
721275970ScyThis is the &ldquo;trusted key number&rdquo; option. 
722275970ScyThis option takes a string argument <span class="file">tkey</span>.
723275970Scy
724275970Scy<p class="noindent">This option has some usage constraints.  It:
725275970Scy     <ul>
726275970Scy<li>may appear an unlimited number of times. 
727275970Scy</ul>
728275970Scy
729275970Scy  <p>Add the specified key number to the trusted key list. 
730275970Scy<div class="node">
731275970Scy<p><hr>
732275970Scy<a name="ntpd-user"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-updateinterval">ntpd updateinterval</a>,
733275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-trustedkey">ntpd trustedkey</a>,
734275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
735275970Scy<br>
736275970Scy</div>
737275970Scy
738275970Scy<h4 class="subsection">user option (-u)</h4>
739275970Scy
740275970Scy<p><a name="index-ntpd_002duser-25"></a>
741275970ScyThis is the &ldquo;run as userid (or userid:groupid)&rdquo; option. 
742275970ScyThis option takes a string argument.
743275970Scy
744275970Scy<p class="noindent">This option has some usage constraints.  It:
745275970Scy     <ul>
746275970Scy<li>must be compiled in by defining <code>HAVE_DROPROOT</code> during the compilation. 
747275970Scy</ul>
748275970Scy
749275970Scy  <p>Specify a user, and optionally a group, to switch to. 
750275970ScyThis option is only available if the OS supports adjusting the clock
751275970Scywithout full root privileges. 
752275970ScyThis option is supported under NetBSD (configure with
753275970Scy<code>--enable-clockctl</code>) or Linux (configure with
754275970Scy<code>--enable-linuxcaps</code>) or Solaris (configure with <code>--enable-solarisprivs</code>). 
755275970Scy<div class="node">
756275970Scy<p><hr>
757275970Scy<a name="ntpd-updateinterval"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-wait_002dsync">ntpd wait-sync</a>,
758275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-user">ntpd user</a>,
759275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
760275970Scy<br>
761275970Scy</div>
762275970Scy
763275970Scy<h4 class="subsection">updateinterval option (-U)</h4>
764275970Scy
765275970Scy<p><a name="index-ntpd_002dupdateinterval-26"></a>
766275970ScyThis is the &ldquo;interval in seconds between scans for new or dropped interfaces&rdquo; option. 
767275970ScyThis option takes a number argument. 
768275970ScyGive the time in seconds between two scans for new or dropped interfaces. 
769275970ScyFor systems with routing socket support the scans will be performed shortly after the interface change
770275970Scyhas been detected by the system. 
771275970ScyUse 0 to disable scanning. 60 seconds is the minimum time between scans. 
772275970Scy<div class="node">
773275970Scy<p><hr>
774275970Scy<a name="ntpd-wait_002dsync"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-slew">ntpd slew</a>,
775275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-updateinterval">ntpd updateinterval</a>,
776275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
777275970Scy<br>
778275970Scy</div>
779275970Scy
780275970Scy<h4 class="subsection">wait-sync option (-w)</h4>
781275970Scy
782275970Scy<p><a name="index-ntpd_002dwait_002dsync-27"></a>
783275970ScyThis is the &ldquo;seconds to wait for first clock sync&rdquo; option. 
784275970ScyThis option takes a number argument.
785275970Scy
786275970Scy<p class="noindent">This option has some usage constraints.  It:
787275970Scy     <ul>
788275970Scy<li>must be compiled in by defining <code>HAVE_WORKING_FORK</code> during the compilation. 
789275970Scy<li>must not appear in combination with any of the following options:
790275970Scynofork, quit, saveconfigquit. 
791275970Scy</ul>
792275970Scy
793275970Scy  <p>If greater than zero, alters <code>ntpd</code>'s behavior when forking to
794275970Scydaemonize.  Instead of exiting with status 0 immediately after
795275970Scythe fork, the parent waits up to the specified number of
796275970Scyseconds for the child to first synchronize the clock.  The exit
797275970Scystatus is zero (success) if the clock was synchronized,
798275970Scyotherwise it is <code>ETIMEDOUT</code>. 
799275970ScyThis provides the option for a script starting <code>ntpd</code> to easily
800275970Scywait for the first set of the clock before proceeding. 
801275970Scy<div class="node">
802275970Scy<p><hr>
803275970Scy<a name="ntpd-slew"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-usepcc">ntpd usepcc</a>,
804275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-wait_002dsync">ntpd wait-sync</a>,
805275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
806275970Scy<br>
807275970Scy</div>
808275970Scy
809275970Scy<h4 class="subsection">slew option (-x)</h4>
810275970Scy
811275970Scy<p><a name="index-ntpd_002dslew-28"></a>
812275970ScyThis is the &ldquo;slew up to 600 seconds&rdquo; option. 
813275970ScyNormally, 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. 
814275970ScyThis option sets the threshold to 600 s, which is well within the accuracy window to set the clock manually. 
815275970ScyNote: 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. 
816275970ScyThus, an adjustment as much as 600 s will take almost 14 days to complete. 
817275970ScyThis option can be used with the
818275970Scy<code>-g</code>
819275970Scyand
820275970Scy<code>-q</code>
821275970Scyoptions. 
822275970ScySee the
823275970Scy<code>tinker</code>
824275970Scyconfiguration file directive for other options. 
825275970ScyNote: The kernel time discipline is disabled with this option. 
826275970Scy<div class="node">
827275970Scy<p><hr>
828275970Scy<a name="ntpd-usepcc"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-pccfreq">ntpd pccfreq</a>,
829275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-slew">ntpd slew</a>,
830275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
831275970Scy<br>
832275970Scy</div>
833275970Scy
834275970Scy<h4 class="subsection">usepcc option</h4>
835275970Scy
836275970Scy<p><a name="index-ntpd_002dusepcc-29"></a>
837275970ScyThis is the &ldquo;use cpu cycle counter (windows only)&rdquo; option.
838275970Scy
839275970Scy<p class="noindent">This option has some usage constraints.  It:
840275970Scy     <ul>
841275970Scy<li>must be compiled in by defining <code>SYS_WINNT</code> during the compilation. 
842275970Scy</ul>
843275970Scy
844275970Scy  <p>Attempt to substitute the CPU counter for <code>QueryPerformanceCounter</code>. 
845275970ScyThe CPU counter and <code>QueryPerformanceCounter</code> are compared, and if
846275970Scythey have the same frequency, the CPU counter (RDTSC on x86) is
847275970Scyused directly, saving the overhead of a system call. 
848275970Scy<div class="node">
849275970Scy<p><hr>
850275970Scy<a name="ntpd-pccfreq"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-mdns">ntpd mdns</a>,
851275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-usepcc">ntpd usepcc</a>,
852275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
853275970Scy<br>
854275970Scy</div>
855275970Scy
856275970Scy<h4 class="subsection">pccfreq option</h4>
857275970Scy
858275970Scy<p><a name="index-ntpd_002dpccfreq-30"></a>
859275970ScyThis is the &ldquo;force cpu cycle counter use (windows only)&rdquo; option. 
860275970ScyThis option takes a string argument.
861275970Scy
862275970Scy<p class="noindent">This option has some usage constraints.  It:
863275970Scy     <ul>
864275970Scy<li>must be compiled in by defining <code>SYS_WINNT</code> during the compilation. 
865275970Scy</ul>
866275970Scy
867275970Scy  <p>Force substitution the CPU counter for <code>QueryPerformanceCounter</code>. 
868275970ScyThe CPU counter (RDTSC on x86) is used unconditionally with the
869275970Scygiven frequency (in Hz). 
870275970Scy<div class="node">
871275970Scy<p><hr>
872275970Scy<a name="ntpd-mdns"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-config">ntpd config</a>,
873275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-pccfreq">ntpd pccfreq</a>,
874275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
875275970Scy<br>
876275970Scy</div>
877275970Scy
878275970Scy<h4 class="subsection">mdns option (-m)</h4>
879275970Scy
880275970Scy<p><a name="index-ntpd_002dmdns-31"></a>
881275970ScyThis is the &ldquo;register with mdns as a ntp server&rdquo; option.
882275970Scy
883275970Scy<p class="noindent">This option has some usage constraints.  It:
884275970Scy     <ul>
885275970Scy<li>must be compiled in by defining <code>HAVE_DNSREGISTRATION</code> during the compilation. 
886275970Scy</ul>
887275970Scy
888275970Scy  <p>Registers as an NTP server with the local mDNS server which allows
889275970Scythe server to be discovered via mDNS client lookup.
890275970Scy
891275970Scy<div class="node">
892275970Scy<p><hr>
893275970Scy<a name="ntpd-config"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-exit-status">ntpd exit status</a>,
894275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-mdns">ntpd mdns</a>,
895275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
896275970Scy<br>
897275970Scy</div>
898275970Scy
899275970Scy<h4 class="subsection">presetting/configuring ntpd</h4>
900275970Scy
901275970Scy<p>Any option that is not marked as <i>not presettable</i> may be preset by
902275970Scyloading values from environment variables named <code>NTPD</code> and <code>NTPD_&lt;OPTION_NAME&gt;</code>.  <code>&lt;OPTION_NAME&gt;</code> must be one of
903275970Scythe options listed above in upper case and segmented with underscores. 
904275970ScyThe <code>NTPD</code> variable will be tokenized and parsed like
905275970Scythe command line.  The remaining variables are tested for existence and their
906275970Scyvalues are treated like option arguments.
907275970Scy
908275970Scy  <p>The command line options relating to configuration and/or usage help are:
909275970Scy
910275970Scy<h5 class="subsubheading">version (-)</h5>
911275970Scy
912275970Scy<p>Print the program version to standard out, optionally with licensing
913275970Scyinformation, then exit 0.  The optional argument specifies how much licensing
914275970Scydetail to provide.  The default is to print just the version.  The licensing infomation may be selected with an option argument. 
915275970ScyOnly the first letter of the argument is examined:
916275970Scy
917275970Scy     <dl>
918275970Scy<dt><span class="samp">version</span><dd>Only print the version.  This is the default. 
919275970Scy<br><dt><span class="samp">copyright</span><dd>Name the copyright usage licensing terms. 
920275970Scy<br><dt><span class="samp">verbose</span><dd>Print the full copyright usage licensing terms. 
921275970Scy</dl>
922275970Scy
923275970Scy<div class="node">
924275970Scy<p><hr>
925275970Scy<a name="ntpd-exit-status"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-Usage">ntpd Usage</a>,
926275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-config">ntpd config</a>,
927275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
928275970Scy<br>
929275970Scy</div>
930275970Scy
931275970Scy<h4 class="subsection">ntpd exit status</h4>
932275970Scy
933275970Scy<p>One of the following exit values will be returned:
934275970Scy     <dl>
935275970Scy<dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution. 
936275970Scy<br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid. 
937275970Scy</dl>
938275970Scy  <div class="node">
939275970Scy<p><hr>
940275970Scy<a name="ntpd-Usage"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-Files">ntpd Files</a>,
941275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-exit-status">ntpd exit status</a>,
942275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
943275970Scy<br>
944275970Scy</div>
945275970Scy
946275970Scy<h4 class="subsection">ntpd Usage</h4>
947275970Scy
948275970Scy<div class="node">
949275970Scy<p><hr>
950275970Scy<a name="ntpd-Files"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-See-Also">ntpd See Also</a>,
951275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-Usage">ntpd Usage</a>,
952275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
953275970Scy<br>
954275970Scy</div>
955275970Scy
956275970Scy<h4 class="subsection">ntpd Files</h4>
957275970Scy
958275970Scy<div class="node">
959275970Scy<p><hr>
960275970Scy<a name="ntpd-See-Also"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-Bugs">ntpd Bugs</a>,
961275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-Files">ntpd Files</a>,
962275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
963275970Scy<br>
964275970Scy</div>
965275970Scy
966275970Scy<h4 class="subsection">ntpd See Also</h4>
967275970Scy
968275970Scy<div class="node">
969275970Scy<p><hr>
970275970Scy<a name="ntpd-Bugs"></a>Next:&nbsp;<a rel="next" accesskey="n" href="#ntpd-Notes">ntpd Notes</a>,
971275970ScyPrevious:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-See-Also">ntpd See Also</a>,
972275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
973275970Scy<br>
974275970Scy</div>
975275970Scy
976275970Scy<h4 class="subsection">ntpd Bugs</h4>
977275970Scy
978275970Scy<div class="node">
979275970Scy<p><hr>
980275970Scy<a name="ntpd-Notes"></a>Previous:&nbsp;<a rel="previous" accesskey="p" href="#ntpd-Bugs">ntpd Bugs</a>,
981275970ScyUp:&nbsp;<a rel="up" accesskey="u" href="#ntpd-Invocation">ntpd Invocation</a>
982275970Scy<br>
983275970Scy</div>
984275970Scy
985275970Scy<h4 class="subsection">ntpd Notes</h4>
986275970Scy
987275970Scy<div class="node">
988275970Scy<p><hr>
989275970Scy<a name="Usage"></a>
990275970Scy<br>
991275970Scy</div>
992275970Scy
993275970Scy<!-- node-name,  next,  previous,  up -->
994275970Scy<h3 class="section">Usage</h3>
995275970Scy
996