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! 22: <h1 class="settitle">Sntp User's Manual</h1>
! 23: <div class="node">
! 24: <p><hr>
! 25: <a name="Top"></a>Next: <a rel="next" accesskey="n" href="#sntp-Description">sntp Description</a>,
! 26: Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>,
! 27: Up: <a rel="up" accesskey="u" href="#dir">(dir)</a>
! 28: <br>
! 29: </div>
! 30:
! 31: <h2 class="unnumbered">Simple Network Time Protocol User Manual</h2>
! 32:
! 33: <p>This document describes the use of the NTP Project's <code>sntp</code> program,
! 34: that can be used to query a Network Time Protocol (NTP) server and
! 35: display the time offset of the system clock relative to the server
! 36: clock. Run as root, it can correct the system clock to this offset as
! 37: well. It can be run as an interactive command or from a cron job.
! 38:
! 39: <p>This document applies to version 4.2.6p5 of <code>sntp</code>.
! 40:
! 41: <p>The program implements the SNTP protocol as defined by RFC 5905, the NTPv4
! 42: IETF specification.
! 43:
! 44: <div class="shortcontents">
! 45: <h2>Short Contents</h2>
! 46: <ul>
! 47: <a href="#Top">Simple Network Time Protocol User Manual</a>
! 48: </ul>
! 49: </div>
! 50:
! 51: <ul class="menu">
! 52: <li><a accesskey="1" href="#sntp-Description">sntp Description</a>: Description
! 53: <li><a accesskey="2" href="#sntp-Invocation">sntp Invocation</a>: Invoking sntp
! 54: <li><a accesskey="3" href="#Usage">Usage</a>: Usage
! 55: </ul>
! 56:
! 57: <div class="node">
! 58: <p><hr>
! 59: <a name="sntp-Description"></a>
! 60: <br>
! 61: </div>
! 62:
! 63: <!-- node-name, next, previous, up -->
! 64: <h3 class="section">Description</h3>
! 65:
! 66: <p>By default, <code>sntp</code> writes the local data and time (i.e., not UTC) to the
! 67: standard output in the format:
! 68:
! 69: <pre class="example"> 1996 Oct 15 20:17:25.123 +4.567 +/- 0.089 secs
! 70: </pre>
! 71: <p>where the +4.567 +/- 0.089 secs indicates the time offset and
! 72: error bound of the system clock relative to the server clock.
! 73:
! 74: <div class="node">
! 75: <p><hr>
! 76: <a name="sntp-Invocation"></a>
! 77: <br>
! 78: </div>
! 79:
! 80: <h3 class="section">Invoking sntp</h3>
! 81:
! 82: <p><a name="index-sntp-1"></a><a name="index-standard-Simple-Network-Time-Protocol-program-2"></a>
! 83: <code>sntp</code>
! 84: can be used as a SNTP client to query a NTP or SNTP server and either display
! 85: the time or set the local system's time (given suitable privilege). It can be
! 86: run as an interactive command or in a
! 87: <code>cron</code>
! 88: job.
! 89:
! 90: <p>NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol)
! 91: are defined and described by RFC 5905.
! 92:
! 93: <p class="indent">The default is to write the estimated correct local date and time (i.e. not
! 94: UTC) to the standard output in a format like
! 95: <pre class="example"> 1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs
! 96: </pre>
! 97: <p>where the
! 98: <pre class="example"> +4.567 +/- 0.089 secs
! 99: </pre>
! 100: <p>indicates the local clock is 4.567 seconds behind the correct time
! 101: (so 4.567 seconds must be added to the local clock to get it to be correct),
! 102: and the (local) time of
! 103: <code>1996-10-15 20:17:25.123</code>
! 104: can be converted to UTC time by adding 8 hours and 0 minutes, and
! 105: is believed to be correct to within
! 106: <code>+/- 0.089</code>
! 107: seconds.
! 108:
! 109: <p>This section was generated by <strong>AutoGen</strong>,
! 110: the aginfo template and the option descriptions for the <span class="command">sntp</span> program. It documents the <span class="command">sntp</span> usage text and option meanings.
! 111:
! 112: <p>This software is released under a specialized copyright license.
! 113:
! 114: <ul class="menu">
! 115: <li><a accesskey="1" href="#sntp-usage">sntp usage</a>: sntp usage help (-?)
! 116: <li><a accesskey="2" href="#sntp-adjtime">sntp adjtime</a>: adjtime option (-j)
! 117: <li><a accesskey="3" href="#sntp-authentication">sntp authentication</a>: authentication option (-a)
! 118: <li><a accesskey="4" href="#sntp-broadcast">sntp broadcast</a>: broadcast option (-b)
! 119: <li><a accesskey="5" href="#sntp-ipv4">sntp ipv4</a>: ipv4 option (-4)
! 120: <li><a accesskey="6" href="#sntp-ipv6">sntp ipv6</a>: ipv6 option (-6)
! 121: <li><a accesskey="7" href="#sntp-keyfile">sntp keyfile</a>: keyfile option (-k)
! 122: <li><a accesskey="8" href="#sntp-kod">sntp kod</a>: kod option (-K)
! 123: <li><a accesskey="9" href="#sntp-logfile">sntp logfile</a>: logfile option (-l)
! 124: <li><a href="#sntp-normalverbose">sntp normalverbose</a>: normalverbose option (-d)
! 125: <li><a href="#sntp-settod">sntp settod</a>: settod option (-s)
! 126: <li><a href="#sntp-syslog">sntp syslog</a>: syslog option (-p)
! 127: <li><a href="#sntp-timeout">sntp timeout</a>: timeout option (-t)
! 128: </ul>
! 129:
! 130: <div class="node">
! 131: <p><hr>
! 132: <a name="sntp-usage"></a>Next: <a rel="next" accesskey="n" href="#sntp-adjtime">sntp adjtime</a>,
! 133: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 134: <br>
! 135: </div>
! 136:
! 137: <h4 class="subsection">sntp usage help (-?)</h4>
! 138:
! 139: <p><a name="index-sntp-usage-3"></a>
! 140: This is the automatically generated usage text for sntp:
! 141:
! 142: <pre class="example">sntp - standard Simple Network Time Protocol program - Ver. 4.2.6p5
! 143: USAGE: sntp [ -<flag> [<val>] | --<name>[{=| }<val>] ]... \
! 144: [ hostname-or-IP ...]
! 145: Flg Arg Option-Name Description
! 146: -4 no ipv4 Force IPv4 DNS name resolution
! 147: - prohibits these options:
! 148: ipv6
! 149: -6 no ipv6 Force IPv6 DNS name resolution
! 150: - prohibits these options:
! 151: ipv4
! 152: -d no normalverbose Normal verbose
! 153: -K Str kod KoD history filename
! 154: -p no syslog Logging with syslog
! 155: - prohibits these options:
! 156: logfile
! 157: -l Str logfile Log to specified logfile
! 158: - prohibits these options:
! 159: syslog
! 160: -s no settod Set (step) the time with settimeofday()
! 161: - prohibits these options:
! 162: adjtime
! 163: -j no adjtime Set (slew) the time with adjtime()
! 164: - prohibits these options:
! 165: settod
! 166: -b Str broadcast Use broadcasts to the address specified for synchronisation
! 167: -t Num timeout Specify the number of seconds to wait for broadcasts
! 168: -a Num authentication Enable authentication with the key auth-keynumber
! 169: -k Str keyfile Specify a keyfile. SNTP will look in this file for the key specified with -a
! 170: opt version Output version information and exit
! 171: -? no help Display extended usage information and exit
! 172: -! no more-help Extended usage information passed thru pager
! 173: -> opt save-opts Save the option state to a config file
! 174: -< Str load-opts Load options from a config file
! 175: - disabled as --no-load-opts
! 176: - may appear multiple times
! 177:
! 178: Options are specified by doubled hyphens and their name or by a single
! 179: hyphen and the flag character.
! 180:
! 181:
! 182:
! 183: The following option preset mechanisms are supported:
! 184: - reading file $HOME/.ntprc
! 185: - reading file ./.ntprc
! 186: - examining environment variables named SNTP_*
! 187:
! 188: sntp implements the Simple Network Time Protocol, and is used to query an
! 189: NTP or SNTP server and either display the time or set the local system's
! 190: time (given suitable privilege).
! 191:
! 192: It can be run interactively from the command line or as a cron job.
! 193:
! 194: NTP and SNTP are defined by RFC 5905, which obsoletes RFC 4330 and RFC
! 195: 1305.
! 196:
! 197: please send bug reports to: http://bugs.ntp.org, bugs@ntp.org
! 198: </pre>
! 199: <div class="node">
! 200: <p><hr>
! 201: <a name="sntp-adjtime"></a>Next: <a rel="next" accesskey="n" href="#sntp-authentication">sntp authentication</a>,
! 202: Previous: <a rel="previous" accesskey="p" href="#sntp-usage">sntp usage</a>,
! 203: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 204: <br>
! 205: </div>
! 206:
! 207: <h4 class="subsection">adjtime option (-j)</h4>
! 208:
! 209: <p><a name="index-sntp_002dadjtime-4"></a>
! 210: This is the “set (slew) the time with adjtime()” option.
! 211:
! 212: <p>This option has some usage constraints. It:
! 213: <ul>
! 214: <li>must not appear in combination with any of the following options:
! 215: settod.
! 216: </ul>
! 217:
! 218: <div class="node">
! 219: <p><hr>
! 220: <a name="sntp-authentication"></a>Next: <a rel="next" accesskey="n" href="#sntp-broadcast">sntp broadcast</a>,
! 221: Previous: <a rel="previous" accesskey="p" href="#sntp-adjtime">sntp adjtime</a>,
! 222: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 223: <br>
! 224: </div>
! 225:
! 226: <h4 class="subsection">authentication option (-a)</h4>
! 227:
! 228: <p><a name="index-sntp_002dauthentication-5"></a>
! 229: This is the “enable authentication with the key auth-keynumber” option.
! 230: This option enables authentication using the key specified in this option's argument.
! 231: The argument of this option is the keyid, a number specified in the keyfile as this
! 232: key's identifier. See the keyfile option (-k) for more details.
! 233:
! 234: <div class="node">
! 235: <p><hr>
! 236: <a name="sntp-broadcast"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv4">sntp ipv4</a>,
! 237: Previous: <a rel="previous" accesskey="p" href="#sntp-authentication">sntp authentication</a>,
! 238: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 239: <br>
! 240: </div>
! 241:
! 242: <h4 class="subsection">broadcast option (-b)</h4>
! 243:
! 244: <p><a name="index-sntp_002dbroadcast-6"></a>
! 245: This is the “use broadcasts to the address specified for synchronisation” option.
! 246: If specified SNTP will listen to the specified broadcast address
! 247: for NTP broadcasts. The default maximum wait time,
! 248: 68 seconds, can be modified with -t.
! 249:
! 250: <div class="node">
! 251: <p><hr>
! 252: <a name="sntp-ipv4"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv6">sntp ipv6</a>,
! 253: Previous: <a rel="previous" accesskey="p" href="#sntp-broadcast">sntp broadcast</a>,
! 254: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 255: <br>
! 256: </div>
! 257:
! 258: <h4 class="subsection">ipv4 option (-4)</h4>
! 259:
! 260: <p><a name="index-sntp_002dipv4-7"></a>
! 261: This is the “force ipv4 dns name resolution” option.
! 262:
! 263: <p>This option has some usage constraints. It:
! 264: <ul>
! 265: <li>must not appear in combination with any of the following options:
! 266: ipv6.
! 267: </ul>
! 268:
! 269: <p>Force DNS resolution of the following host names on the command line
! 270: to the IPv4 namespace.
! 271:
! 272: <div class="node">
! 273: <p><hr>
! 274: <a name="sntp-ipv6"></a>Next: <a rel="next" accesskey="n" href="#sntp-keyfile">sntp keyfile</a>,
! 275: Previous: <a rel="previous" accesskey="p" href="#sntp-ipv4">sntp ipv4</a>,
! 276: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 277: <br>
! 278: </div>
! 279:
! 280: <h4 class="subsection">ipv6 option (-6)</h4>
! 281:
! 282: <p><a name="index-sntp_002dipv6-8"></a>
! 283: This is the “force ipv6 dns name resolution” option.
! 284:
! 285: <p>This option has some usage constraints. It:
! 286: <ul>
! 287: <li>must not appear in combination with any of the following options:
! 288: ipv4.
! 289: </ul>
! 290:
! 291: <p>Force DNS resolution of the following host names on the command line
! 292: to the IPv6 namespace.
! 293:
! 294: <div class="node">
! 295: <p><hr>
! 296: <a name="sntp-keyfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-kod">sntp kod</a>,
! 297: Previous: <a rel="previous" accesskey="p" href="#sntp-ipv6">sntp ipv6</a>,
! 298: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 299: <br>
! 300: </div>
! 301:
! 302: <h4 class="subsection">keyfile option (-k)</h4>
! 303:
! 304: <p><a name="index-sntp_002dkeyfile-9"></a>
! 305: This is the “specify a keyfile. sntp will look in this file for the key specified with -a” option.
! 306: This option specifies the keyfile. SNTP will search for the key specified with -a keyno in this
! 307: file. Key files follow the following format:
! 308:
! 309: <p>keyid keytype key
! 310:
! 311: <p>Where keyid is a number identifying this key
! 312: keytype is one of the follow:
! 313: S Key in 64 Bit hexadecimal number as specified in in the DES specification.
! 314: N Key in 64 Bit hexadecimal number as specified in the NTP standard.
! 315: A Key in a 1-to-8 character ASCII string.
! 316: M Key in a 1-to-8 character ASCII string using the MD5 authentication scheme.
! 317:
! 318: <p>For more information see ntp.keys(5).
! 319:
! 320: <div class="node">
! 321: <p><hr>
! 322: <a name="sntp-kod"></a>Next: <a rel="next" accesskey="n" href="#sntp-logfile">sntp logfile</a>,
! 323: Previous: <a rel="previous" accesskey="p" href="#sntp-keyfile">sntp keyfile</a>,
! 324: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 325: <br>
! 326: </div>
! 327:
! 328: <h4 class="subsection">kod option (-K)</h4>
! 329:
! 330: <p><a name="index-sntp_002dkod-10"></a>
! 331: This is the “kod history filename” option.
! 332: Specifies the filename to be used to persist the history of KoD
! 333: responses received from servers. The default is
! 334: /var/db/ntp-kod.
! 335:
! 336: <div class="node">
! 337: <p><hr>
! 338: <a name="sntp-logfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-normalverbose">sntp normalverbose</a>,
! 339: Previous: <a rel="previous" accesskey="p" href="#sntp-kod">sntp kod</a>,
! 340: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 341: <br>
! 342: </div>
! 343:
! 344: <h4 class="subsection">logfile option (-l)</h4>
! 345:
! 346: <p><a name="index-sntp_002dlogfile-11"></a>
! 347: This is the “log to specified logfile” option.
! 348:
! 349: <p>This option has some usage constraints. It:
! 350: <ul>
! 351: <li>must not appear in combination with any of the following options:
! 352: syslog.
! 353: </ul>
! 354:
! 355: <p>This option causes the client to write log messages to the specified
! 356: logfile.
! 357:
! 358: <div class="node">
! 359: <p><hr>
! 360: <a name="sntp-normalverbose"></a>Next: <a rel="next" accesskey="n" href="#sntp-settod">sntp settod</a>,
! 361: Previous: <a rel="previous" accesskey="p" href="#sntp-logfile">sntp logfile</a>,
! 362: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 363: <br>
! 364: </div>
! 365:
! 366: <h4 class="subsection">normalverbose option (-d)</h4>
! 367:
! 368: <p><a name="index-sntp_002dnormalverbose-12"></a>
! 369: This is the “normal verbose” option.
! 370: Diagnostic messages for non-fatal errors and a limited amount of
! 371: tracing should be written to standard error. Fatal ones always
! 372: produce a diagnostic. This option should be set when there is a
! 373: suspected problem with the server, network or the source.
! 374:
! 375: <div class="node">
! 376: <p><hr>
! 377: <a name="sntp-settod"></a>Next: <a rel="next" accesskey="n" href="#sntp-syslog">sntp syslog</a>,
! 378: Previous: <a rel="previous" accesskey="p" href="#sntp-normalverbose">sntp normalverbose</a>,
! 379: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 380: <br>
! 381: </div>
! 382:
! 383: <h4 class="subsection">settod option (-s)</h4>
! 384:
! 385: <p><a name="index-sntp_002dsettod-13"></a>
! 386: This is the “set (step) the time with settimeofday()” option.
! 387:
! 388: <p>This option has some usage constraints. It:
! 389: <ul>
! 390: <li>must not appear in combination with any of the following options:
! 391: adjtime.
! 392: </ul>
! 393:
! 394: <div class="node">
! 395: <p><hr>
! 396: <a name="sntp-syslog"></a>Next: <a rel="next" accesskey="n" href="#sntp-timeout">sntp timeout</a>,
! 397: Previous: <a rel="previous" accesskey="p" href="#sntp-settod">sntp settod</a>,
! 398: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 399: <br>
! 400: </div>
! 401:
! 402: <h4 class="subsection">syslog option (-p)</h4>
! 403:
! 404: <p><a name="index-sntp_002dsyslog-14"></a>
! 405: This is the “logging with syslog” option.
! 406:
! 407: <p>This option has some usage constraints. It:
! 408: <ul>
! 409: <li>must not appear in combination with any of the following options:
! 410: logfile.
! 411: </ul>
! 412:
! 413: <p>When this option is set all logging will be done using syslog.
! 414:
! 415: <div class="node">
! 416: <p><hr>
! 417: <a name="sntp-timeout"></a>Previous: <a rel="previous" accesskey="p" href="#sntp-syslog">sntp syslog</a>,
! 418: Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a>
! 419: <br>
! 420: </div>
! 421:
! 422: <h4 class="subsection">timeout option (-t)</h4>
! 423:
! 424: <p><a name="index-sntp_002dtimeout-15"></a>
! 425: This is the “specify the number of seconds to wait for broadcasts” option.
! 426: When waiting for a broadcast packet SNTP will wait the number
! 427: of seconds specified before giving up. Default 68 seconds.
! 428:
! 429: <div class="node">
! 430: <p><hr>
! 431: <a name="Usage"></a>
! 432: <br>
! 433: </div>
! 434:
! 435: <!-- node-name, next, previous, up -->
! 436: <h3 class="section">Usage</h3>
! 437:
! 438: <p>The simplest use of this program is as an unprivileged command to
! 439: check the current time, offset, and error in the local clock.
! 440: For example:
! 441:
! 442: <pre class="example"> sntp ntpserver.somewhere
! 443: </pre>
! 444: <p>With suitable privilege, it can be run as a command or in a
! 445: <code>crom</code> job to reset the local clock from a reliable server, like
! 446: the <code>ntpdate</code> and <code>rdate</code> commands.
! 447: For example:
! 448:
! 449: <pre class="example"> sntp -a ntpserver.somewhere
! 450: </pre>
! 451: </body></html>
! 452:
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