| 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 "60049f51e9c8305afe30eb22b711c5c6">
|
|---|
| 11 | <!ENTITY ntp-size "6.9 MB">
|
|---|
| 12 | <!ENTITY ntp-buildsize "104 MB (with tests)">
|
|---|
| 13 | <!ENTITY ntp-time "less than 1 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 | &lfs79_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 &&
|
|---|
| 96 | useradd -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; &&
|
|---|
| 108 | make</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 &&
|
|---|
| 115 | install -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><option>--with-lineeditlibs=readline</option>: This option enables
|
|---|
| 130 | <application>Readline</application> support for <command>ntpdc</command>
|
|---|
| 131 | 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 > /etc/ntp.conf << "EOF"
|
|---|
| 170 | <literal># Asia
|
|---|
| 171 | server 0.asia.pool.ntp.org
|
|---|
| 172 |
|
|---|
| 173 | # Australia
|
|---|
| 174 | server 0.oceania.pool.ntp.org
|
|---|
| 175 |
|
|---|
| 176 | # Europe
|
|---|
| 177 | server 0.europe.pool.ntp.org
|
|---|
| 178 |
|
|---|
| 179 | # North America
|
|---|
| 180 | server 0.north-america.pool.ntp.org
|
|---|
| 181 |
|
|---|
| 182 | # South America
|
|---|
| 183 | server 2.south-america.pool.ntp.org
|
|---|
| 184 |
|
|---|
| 185 | driftfile /var/lib/ntp/ntp.drift
|
|---|
| 186 | pidfile /var/run/ntpd.pid
|
|---|
| 187 |
|
|---|
| 188 | leapfile /etc/ntp.leapseconds</literal>
|
|---|
| 189 | EOF</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 >> /etc/ntp.conf << "EOF"
|
|---|
| 198 | <literal># Security session
|
|---|
| 199 | restrict default limited kod nomodify notrap nopeer noquery
|
|---|
| 200 | restrict -6 default limited kod nomodify notrap nopeer noquery
|
|---|
| 201 |
|
|---|
| 202 | restrict 127.0.0.1
|
|---|
| 203 | restrict ::1</literal>
|
|---|
| 204 | EOF</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>
|
|---|
| 217 | To start the <command>ntpd</command> daemon at boot,
|
|---|
| 218 | install the systemd unit from the <xref linkend="bootscripts"/>
|
|---|
| 219 | package by running the following command as the
|
|---|
| 220 | <systemitem class="username">root</systemitem> user:
|
|---|
| 221 | </para>
|
|---|
| 222 |
|
|---|
| 223 | <indexterm zone="ntp ntp-init">
|
|---|
| 224 | <primary sortas="f-ntp">ntp</primary>
|
|---|
| 225 | </indexterm>
|
|---|
| 226 |
|
|---|
| 227 | <screen role="root"><userinput>make install-ntpd</userinput></screen>
|
|---|
| 228 |
|
|---|
| 229 | <para>If you prefer to run <command>ntpd</command> periodically, add the
|
|---|
| 230 | following command to <systemitem class="username">root</systemitem>'s
|
|---|
| 231 | <filename>crontab</filename>:</para>
|
|---|
| 232 |
|
|---|
| 233 | <screen><literal>ntpd -q</literal></screen>
|
|---|
| 234 |
|
|---|
| 235 | </sect3>
|
|---|
| 236 |
|
|---|
| 237 | </sect2>
|
|---|
| 238 |
|
|---|
| 239 | <sect2 role="content">
|
|---|
| 240 | <title>Contents</title>
|
|---|
| 241 |
|
|---|
| 242 | <segmentedlist>
|
|---|
| 243 | <segtitle>Installed Programs</segtitle>
|
|---|
| 244 | <segtitle>Installed Libraries</segtitle>
|
|---|
| 245 | <segtitle>Installed Directories</segtitle>
|
|---|
| 246 |
|
|---|
| 247 | <seglistitem>
|
|---|
| 248 | <seg>calc_tickadj, ntp-keygen, ntp-wait, ntpd, ntpdate, ntpdc, ntpq,
|
|---|
| 249 | ntptime, ntptrace, sntp, tickadj and update-leap</seg>
|
|---|
| 250 | <seg>None</seg>
|
|---|
| 251 | <seg>/usr/share/ntp,
|
|---|
| 252 | /usr/share/doc/ntp-4.2.8 and
|
|---|
| 253 | /var/lib/ntp</seg>
|
|---|
| 254 | </seglistitem>
|
|---|
| 255 | </segmentedlist>
|
|---|
| 256 |
|
|---|
| 257 | <variablelist>
|
|---|
| 258 | <bridgehead renderas="sect3">Short Descriptions</bridgehead>
|
|---|
| 259 | <?dbfo list-presentation="list"?>
|
|---|
| 260 | <?dbhtml list-presentation="table"?>
|
|---|
| 261 |
|
|---|
| 262 | <varlistentry id="calc_tickadj">
|
|---|
| 263 | <term><command>calc_tickadj</command></term>
|
|---|
| 264 | <listitem>
|
|---|
| 265 | <para>calculates optimal value for tick given ntp drift file.</para>
|
|---|
| 266 | <indexterm zone="ntp calc_tickadj">
|
|---|
| 267 | <primary sortas="b-calc_tickadj">calc_tickadj</primary>
|
|---|
| 268 | </indexterm>
|
|---|
| 269 | </listitem>
|
|---|
| 270 | </varlistentry>
|
|---|
| 271 |
|
|---|
| 272 | <varlistentry id="ntp-keygen">
|
|---|
| 273 | <term><command>ntp-keygen</command></term>
|
|---|
| 274 | <listitem>
|
|---|
| 275 | <para>generates cryptographic data files used by the NTPv4 authentication
|
|---|
| 276 | and identification schemes.</para>
|
|---|
| 277 | <indexterm zone="ntp ntp-keygen">
|
|---|
| 278 | <primary sortas="b-ntp-keygen">ntp-keygen</primary>
|
|---|
| 279 | </indexterm>
|
|---|
| 280 | </listitem>
|
|---|
| 281 | </varlistentry>
|
|---|
| 282 |
|
|---|
| 283 | <varlistentry id="ntp-wait">
|
|---|
| 284 | <term><command>ntp-wait</command></term>
|
|---|
| 285 | <listitem>
|
|---|
| 286 | <para>is useful at boot time, to delay the boot sequence until
|
|---|
| 287 | <command>ntpd</command> has set the time.</para>
|
|---|
| 288 | <indexterm zone="ntp ntp-wait">
|
|---|
| 289 | <primary sortas="b-ntp-wait">ntp-wait</primary>
|
|---|
| 290 | </indexterm>
|
|---|
| 291 | </listitem>
|
|---|
| 292 | </varlistentry>
|
|---|
| 293 |
|
|---|
| 294 | <varlistentry id="ntpd">
|
|---|
| 295 | <term><command>ntpd</command></term>
|
|---|
| 296 | <listitem>
|
|---|
| 297 | <para>is a ntp daemon that runs in the background and keeps
|
|---|
| 298 | the date and time synchronized based on response from configured
|
|---|
| 299 | ntp servers. It also functions as a ntp server.</para>
|
|---|
| 300 | <indexterm zone="ntp ntpd">
|
|---|
| 301 | <primary sortas="b-ntpd">ntpd</primary>
|
|---|
| 302 | </indexterm>
|
|---|
| 303 | </listitem>
|
|---|
| 304 | </varlistentry>
|
|---|
| 305 |
|
|---|
| 306 | <varlistentry id="ntpdate">
|
|---|
| 307 | <term><command>ntpdate</command></term>
|
|---|
| 308 | <listitem>
|
|---|
| 309 | <para>is a client program that sets the date and time based on
|
|---|
| 310 | the response from an ntp server. This command is deprecated.</para>
|
|---|
| 311 | <indexterm zone="ntp ntpdate">
|
|---|
| 312 | <primary sortas="b-ntpdate">ntpdate</primary>
|
|---|
| 313 | </indexterm>
|
|---|
| 314 | </listitem>
|
|---|
| 315 | </varlistentry>
|
|---|
| 316 |
|
|---|
| 317 | <varlistentry id="ntpdc">
|
|---|
| 318 | <term><command>ntpdc</command></term>
|
|---|
| 319 | <listitem>
|
|---|
| 320 | <para>is used to query the ntp daemon about its current state
|
|---|
| 321 | and to request changes in that state.</para>
|
|---|
| 322 | <indexterm zone="ntp ntpdc">
|
|---|
| 323 | <primary sortas="b-ntpdc">ntpdc</primary>
|
|---|
| 324 | </indexterm>
|
|---|
| 325 | </listitem>
|
|---|
| 326 | </varlistentry>
|
|---|
| 327 |
|
|---|
| 328 | <varlistentry id="ntpq">
|
|---|
| 329 | <term><command>ntpq</command></term>
|
|---|
| 330 | <listitem>
|
|---|
| 331 | <para>is a utility program used to monitor <command>ntpd</command>
|
|---|
| 332 | operations and determine performance.</para>
|
|---|
| 333 | <indexterm zone="ntp ntpq">
|
|---|
| 334 | <primary sortas="b-ntpq">ntpq</primary>
|
|---|
| 335 | </indexterm>
|
|---|
| 336 | </listitem>
|
|---|
| 337 | </varlistentry>
|
|---|
| 338 |
|
|---|
| 339 | <varlistentry id="ntptime">
|
|---|
| 340 | <term><command>ntptime</command></term>
|
|---|
| 341 | <listitem>
|
|---|
| 342 | <para>reads and displays time-related kernel variables.</para>
|
|---|
| 343 | <indexterm zone="ntp ntptime">
|
|---|
| 344 | <primary sortas="b-ntptime">ntptime</primary>
|
|---|
| 345 | </indexterm>
|
|---|
| 346 | </listitem>
|
|---|
| 347 | </varlistentry>
|
|---|
| 348 |
|
|---|
| 349 | <varlistentry id="ntptrace">
|
|---|
| 350 | <term><command>ntptrace</command></term>
|
|---|
| 351 | <listitem>
|
|---|
| 352 | <para>traces a chain of ntp servers back to the primary source.</para>
|
|---|
| 353 | <indexterm zone="ntp ntptrace">
|
|---|
| 354 | <primary sortas="b-ntptrace">ntptrace</primary>
|
|---|
| 355 | </indexterm>
|
|---|
| 356 | </listitem>
|
|---|
| 357 | </varlistentry>
|
|---|
| 358 |
|
|---|
| 359 | <varlistentry id="sntp">
|
|---|
| 360 | <term><command>sntp</command></term>
|
|---|
| 361 | <listitem>
|
|---|
| 362 | <para>is a Simple Network Time Protocol (SNTP) client.</para>
|
|---|
| 363 | <indexterm zone="ntp sntp">
|
|---|
| 364 | <primary sortas="b-sntp">sntp</primary>
|
|---|
| 365 | </indexterm>
|
|---|
| 366 | </listitem>
|
|---|
| 367 | </varlistentry>
|
|---|
| 368 |
|
|---|
| 369 | <varlistentry id="tickadj">
|
|---|
| 370 | <term><command>tickadj</command></term>
|
|---|
| 371 | <listitem>
|
|---|
| 372 | <para>reads, and optionally modifies, several timekeeping-related
|
|---|
| 373 | variables in older kernels that do not have support for precision
|
|---|
| 374 | timekeeping.</para>
|
|---|
| 375 | <indexterm zone="ntp tickadj">
|
|---|
| 376 | <primary sortas="b-tickadj">tickadj</primary>
|
|---|
| 377 | </indexterm>
|
|---|
| 378 | </listitem>
|
|---|
| 379 | </varlistentry>
|
|---|
| 380 |
|
|---|
| 381 | <varlistentry id="update-leap">
|
|---|
| 382 | <term><command>update-leap</command></term>
|
|---|
| 383 | <listitem>
|
|---|
| 384 | <para>is a script to verify and, if necessary, update the leap-second
|
|---|
| 385 | definition file.</para>
|
|---|
| 386 | <indexterm zone="ntp update-leap">
|
|---|
| 387 | <primary sortas="b-update-leap">update-leap</primary>
|
|---|
| 388 | </indexterm>
|
|---|
| 389 | </listitem>
|
|---|
| 390 | </varlistentry>
|
|---|
| 391 |
|
|---|
| 392 | </variablelist>
|
|---|
| 393 |
|
|---|
| 394 | </sect2>
|
|---|
| 395 |
|
|---|
| 396 | </sect1>
|
|---|
