source: networking/netprogs/ntp.xml@ f784198

10.0 10.1 11.0 8.0 8.1 8.2 8.3 8.4 9.0 9.1 basic bdubbs/svn elogind ken/refactor-virt lazarus nosym perl-modules qt5new trunk xry111/git-date xry111/git-date-for-trunk xry111/git-date-test
Last change on this file since f784198 was f784198, checked in by Pierre Labastie <pieere@…>, 5 years ago

Another run of parameter vs option fixes

git-svn-id: svn://svn.linuxfromscratch.org/BLFS/trunk/BOOK@17877 af4574ff-66df-0310-9fd7-8a98e5e911e0

  • Property mode set to 100644
File size: 13.8 KB
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1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4 <!ENTITY % general-entities SYSTEM "../../general.ent">
5 %general-entities;
6
7 <!ENTITY ntp-download-http "https://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2/ntp-&ntp-version;.tar.gz">
8<!-- <!ENTITY ntp-download-ftp "&gentoo-ftp-repo;/ntp-&ntp-version;.tar.gz">-->
9 <!ENTITY ntp-download-ftp " ">
10 <!ENTITY ntp-md5sum "4a8636260435b230636f053ffd070e34">
11 <!ENTITY ntp-size "6.9 MB">
12 <!ENTITY ntp-buildsize "102 MB (with tests)">
13 <!ENTITY ntp-time "0.8 SBU (with tests)">
14]>
15
16<sect1 id="ntp" xreflabel="ntp-&ntp-version;">
17 <?dbhtml filename="ntp.html"?>
18
19 <sect1info>
20 <othername>$LastChangedBy$</othername>
21 <date>$Date$</date>
22 </sect1info>
23
24 <title>ntp-&ntp-version;</title>
25
26 <indexterm zone="ntp">
27 <primary sortas="a-ntp">ntp</primary>
28 </indexterm>
29
30 <sect2 role="package">
31 <title>Introduction to ntp</title>
32
33 <para>The <application>ntp</application> package contains a
34 client and server to keep the time synchronized between various computers over
35 a network. This package is the official reference implementation of the
36 NTP protocol.</para>
37
38 &lfs7a_checked;
39
40 <bridgehead renderas="sect3">Package Information</bridgehead>
41 <itemizedlist spacing="compact">
42 <listitem>
43 <para>Download (HTTP): <ulink url="&ntp-download-http;"/></para>
44 </listitem>
45 <listitem>
46 <para>Download (FTP): <ulink url="&ntp-download-ftp;"/></para>
47 </listitem>
48 <listitem>
49 <para>Download MD5 sum: &ntp-md5sum;</para>
50 </listitem>
51 <listitem>
52 <para>Download size: &ntp-size;</para>
53 </listitem>
54 <listitem>
55 <para>Estimated disk space required: &ntp-buildsize;</para>
56 </listitem>
57 <listitem>
58 <para>Estimated build time: &ntp-time;</para>
59 </listitem>
60 </itemizedlist>
61
62 <bridgehead renderas="sect3">ntp Dependencies</bridgehead>
63
64 <bridgehead renderas="sect4">Required</bridgehead>
65 <para role="required">
66 <xref linkend="wget"/> (runtime, for <command>update-leap</command>) and
67 <xref linkend="which"/>
68 </para>
69
70 <bridgehead renderas="sect4">Optional</bridgehead>
71 <para role="optional">
72 <xref linkend="libcap-pam"/>,
73 <xref linkend="libevent"/>,
74 <xref linkend="openssl"/>,
75 <ulink url="http://www.thrysoee.dk/editline/">libedit</ulink>, and
76 <ulink url="https://www.gnu.org/software/autogen/">libopts from
77 AutoGen</ulink>
78 </para>
79
80 <para condition="html" role="usernotes">User Notes:
81 <ulink url="&blfs-wiki;/ntp"/></para>
82
83 </sect2>
84
85 <sect2 role="installation">
86 <title>Installation of ntp</title>
87
88 <para>
89 There should be a dedicated user and group to take control
90 of the <command>ntpd</command> daemon after it is
91 started. Issue the following commands as the
92 <systemitem class="username">root</systemitem> user:
93 </para>
94
95<screen role="root"><userinput>groupadd -g 87 ntp &amp;&amp;
96useradd -c "Network Time Protocol" -d /var/lib/ntp -u 87 \
97 -g ntp -s /bin/false ntp</userinput></screen>
98
99 <para>Install <application>ntp</application> by running
100 the following commands:</para>
101
102<screen><userinput>./configure --prefix=/usr \
103 --bindir=/usr/sbin \
104 --sysconfdir=/etc \
105 --enable-linuxcaps \
106 --with-lineeditlibs=readline \
107 --docdir=/usr/share/doc/ntp-&ntp-version; &amp;&amp;
108make</userinput></screen>
109
110 <para>To test the results, issue: <command>make check</command>.</para>
111
112 <para>Now, as the <systemitem class="username">root</systemitem> user:</para>
113
114<screen role="root"><userinput>make install &amp;&amp;
115install -v -o ntp -g ntp -d /var/lib/ntp</userinput></screen>
116
117 </sect2>
118
119 <sect2 role="commands">
120 <title>Command Explanations</title>
121
122 <para><parameter>--bindir=/usr/sbin</parameter>: This parameter places
123 the administrative programs in <filename
124 class="directory">/usr/sbin</filename>.</para>
125
126 <para><parameter>--enable-linuxcaps</parameter>: ntpd is run as user
127 ntp, so use Linux capabilities for non-root clock control.</para>
128
129 <para><parameter>--with-lineeditlibs=readline</parameter>: This switch
130 enables <application>Readline</application> support for
131 <command>ntpdc</command> and <command>ntpq</command> programs. If omitted,
132 <application>libedit</application> will be used if installed, otherwise no
133 readline capabilites will be compiled.</para>
134
135 </sect2>
136
137 <sect2 role="configuration">
138 <title>Configuring ntp</title>
139
140 <sect3 id="ntp-config">
141 <title>Config Files</title>
142
143 <para><filename>/etc/ntp.conf</filename></para>
144
145 <indexterm zone="ntp ntp-config">
146 <primary sortas="e-etc-ntp.conf">/etc/ntp.conf</primary>
147 </indexterm>
148
149 </sect3>
150
151 <sect3>
152 <title>Configuration Information</title>
153
154 <para>The following configuration file first defines various ntp
155 servers with open access from different continents. Second, it
156 creates a drift file where <command>ntpd</command> stores the
157 frequency offset and a pid file to store the
158 <command>ntpd</command> process ID. Third, it defines the location
159 for the leap-second definition file
160 <filename>/etc/ntp.leapseconds</filename>, that the
161 <command>update-leap</command> script checks and updates, when
162 necessary. This script can be run as a cron job and the
163 <application>ntp</application> developers recommend a frequency of
164 about three weeks for the updates. Since the documentation included
165 with the package is sparse, visit the ntp website at
166 <ulink url="http://www.ntp.org/"/> and
167 <ulink url="http://www.pool.ntp.org/"/> for more information.</para>
168
169<screen role="root"><userinput>cat &gt; /etc/ntp.conf &lt;&lt; "EOF"
170<literal># Asia
171server 0.asia.pool.ntp.org
172
173# Australia
174server 0.oceania.pool.ntp.org
175
176# Europe
177server 0.europe.pool.ntp.org
178
179# North America
180server 0.north-america.pool.ntp.org
181
182# South America
183server 2.south-america.pool.ntp.org
184
185driftfile /var/lib/ntp/ntp.drift
186pidfile /var/run/ntpd.pid
187
188leapfile /etc/ntp.leapseconds</literal>
189EOF</userinput></screen>
190
191 <para>
192 You may wish to add a <quote>Security session</quote>. For
193 explanations, see
194 <ulink url="https://www.eecis.udel.edu/~mills/ntp/html/accopt.html#restrict"/>.
195 </para>
196
197<screen role="root"><userinput>cat &gt;&gt; /etc/ntp.conf &lt;&lt; "EOF"
198<literal># Security session
199restrict default limited kod nomodify notrap nopeer noquery
200restrict -6 default limited kod nomodify notrap nopeer noquery
201
202restrict 127.0.0.1
203restrict ::1</literal>
204EOF</userinput></screen>
205
206 </sect3>
207
208 <sect3 id="ntp-init">
209 <title>Synchronizing the Time</title>
210
211 <para>There are two options. Option one is to run <command>ntpd</command>
212 continuously and allow it to synchronize the time in a gradual manner. The
213 other option is to run <command>ntpd</command> periodically (using cron)
214 and update the time each time <command>ntpd</command> is scheduled.</para>
215
216 <para>If you choose Option one, then install the
217 <phrase revision="sysv"><filename>/etc/rc.d/init.d/ntp</filename>
218 init script</phrase>
219 <phrase revision="systemd"><filename>ntpd.service</filename> unit</phrase>
220 included in the
221 <xref linkend="bootscripts" revision="sysv"/>
222 <xref linkend="systemd-units" revision="systemd"/> package.</para>
223
224 <indexterm zone="ntp ntp-init" revision="sysv">
225 <primary sortas="f-ntp">ntp</primary>
226 </indexterm>
227
228 <indexterm zone="ntp ntp-init" revision="systemd">
229 <primary sortas="f-ntpd">ntpd.service</primary>
230 </indexterm>
231
232<screen role="root"><userinput>make install-ntpd</userinput></screen>
233
234 <para>If you prefer to run <command>ntpd</command> periodically, add the
235 following command to <systemitem class="username">root</systemitem>'s
236 <filename>crontab</filename>:</para>
237
238<screen><literal>ntpd -q</literal></screen>
239
240 <para revision="sysv">Execute the following command if you would like to
241 set the hardware clock to the current system time at shutdown and
242 reboot:</para>
243
244<screen role="root" revision="sysv"><userinput>ln -v -sf ../init.d/setclock /etc/rc.d/rc0.d/K46setclock &amp;&amp;
245ln -v -sf ../init.d/setclock /etc/rc.d/rc6.d/K46setclock</userinput></screen>
246
247 <para revision="sysv">The other way around is already set up by
248 LFS.</para>
249
250 </sect3>
251
252 </sect2>
253
254 <sect2 role="content">
255 <title>Contents</title>
256
257 <segmentedlist>
258 <segtitle>Installed Programs</segtitle>
259 <segtitle>Installed Libraries</segtitle>
260 <segtitle>Installed Directories</segtitle>
261
262 <seglistitem>
263 <seg>calc_tickadj, ntp-keygen, ntp-wait, ntpd, ntpdate, ntpdc, ntpq,
264 ntptime, ntptrace, sntp, tickadj and update-leap</seg>
265 <seg>None</seg>
266 <seg>/usr/share/ntp,
267 /usr/share/doc/ntp-4.2.8 and
268 /var/lib/ntp</seg>
269 </seglistitem>
270 </segmentedlist>
271
272 <variablelist>
273 <bridgehead renderas="sect3">Short Descriptions</bridgehead>
274 <?dbfo list-presentation="list"?>
275 <?dbhtml list-presentation="table"?>
276
277 <varlistentry id="calc_tickadj">
278 <term><command>calc_tickadj</command></term>
279 <listitem>
280 <para>calculates optimal value for tick given ntp drift file.</para>
281 <indexterm zone="ntp calc_tickadj">
282 <primary sortas="b-calc_tickadj">calc_tickadj</primary>
283 </indexterm>
284 </listitem>
285 </varlistentry>
286
287 <varlistentry id="ntp-keygen">
288 <term><command>ntp-keygen</command></term>
289 <listitem>
290 <para>generates cryptographic data files used by the NTPv4 authentication
291 and identification schemes.</para>
292 <indexterm zone="ntp ntp-keygen">
293 <primary sortas="b-ntp-keygen">ntp-keygen</primary>
294 </indexterm>
295 </listitem>
296 </varlistentry>
297
298 <varlistentry id="ntp-wait">
299 <term><command>ntp-wait</command></term>
300 <listitem>
301 <para>is useful at boot time, to delay the boot sequence until
302 <command>ntpd</command> has set the time.</para>
303 <indexterm zone="ntp ntp-wait">
304 <primary sortas="b-ntp-wait">ntp-wait</primary>
305 </indexterm>
306 </listitem>
307 </varlistentry>
308
309 <varlistentry id="ntpd">
310 <term><command>ntpd</command></term>
311 <listitem>
312 <para>is a ntp daemon that runs in the background and keeps
313 the date and time synchronized based on response from configured
314 ntp servers. It also functions as a ntp server.</para>
315 <indexterm zone="ntp ntpd">
316 <primary sortas="b-ntpd">ntpd</primary>
317 </indexterm>
318 </listitem>
319 </varlistentry>
320
321 <varlistentry id="ntpdate">
322 <term><command>ntpdate</command></term>
323 <listitem>
324 <para>is a client program that sets the date and time based on
325 the response from an ntp server. This command is deprecated.</para>
326 <indexterm zone="ntp ntpdate">
327 <primary sortas="b-ntpdate">ntpdate</primary>
328 </indexterm>
329 </listitem>
330 </varlistentry>
331
332 <varlistentry id="ntpdc">
333 <term><command>ntpdc</command></term>
334 <listitem>
335 <para>is used to query the ntp daemon about its current state
336 and to request changes in that state.</para>
337 <indexterm zone="ntp ntpdc">
338 <primary sortas="b-ntpdc">ntpdc</primary>
339 </indexterm>
340 </listitem>
341 </varlistentry>
342
343 <varlistentry id="ntpq">
344 <term><command>ntpq</command></term>
345 <listitem>
346 <para>is a utility program used to monitor <command>ntpd</command>
347 operations and determine performance.</para>
348 <indexterm zone="ntp ntpq">
349 <primary sortas="b-ntpq">ntpq</primary>
350 </indexterm>
351 </listitem>
352 </varlistentry>
353
354 <varlistentry id="ntptime">
355 <term><command>ntptime</command></term>
356 <listitem>
357 <para>reads and displays time-related kernel variables.</para>
358 <indexterm zone="ntp ntptime">
359 <primary sortas="b-ntptime">ntptime</primary>
360 </indexterm>
361 </listitem>
362 </varlistentry>
363
364 <varlistentry id="ntptrace">
365 <term><command>ntptrace</command></term>
366 <listitem>
367 <para>traces a chain of ntp servers back to the primary source.</para>
368 <indexterm zone="ntp ntptrace">
369 <primary sortas="b-ntptrace">ntptrace</primary>
370 </indexterm>
371 </listitem>
372 </varlistentry>
373
374 <varlistentry id="sntp">
375 <term><command>sntp</command></term>
376 <listitem>
377 <para>is a Simple Network Time Protocol (SNTP) client.</para>
378 <indexterm zone="ntp sntp">
379 <primary sortas="b-sntp">sntp</primary>
380 </indexterm>
381 </listitem>
382 </varlistentry>
383
384 <varlistentry id="tickadj">
385 <term><command>tickadj</command></term>
386 <listitem>
387 <para>reads, and optionally modifies, several timekeeping-related
388 variables in older kernels that do not have support for precision
389 timekeeping.</para>
390 <indexterm zone="ntp tickadj">
391 <primary sortas="b-tickadj">tickadj</primary>
392 </indexterm>
393 </listitem>
394 </varlistentry>
395
396 <varlistentry id="update-leap">
397 <term><command>update-leap</command></term>
398 <listitem>
399 <para>is a script to verify and, if necessary, update the leap-second
400 definition file.</para>
401 <indexterm zone="ntp update-leap">
402 <primary sortas="b-update-leap">update-leap</primary>
403 </indexterm>
404 </listitem>
405 </varlistentry>
406
407 </variablelist>
408
409 </sect2>
410
411</sect1>
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