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1258945Sroberto<html lang="en"> 2258945Sroberto<head> 3258945Sroberto<title>Sntp User's Manual</title> 4258945Sroberto<meta http-equiv="Content-Type" content="text/html"> 5258945Sroberto<meta name="description" content="Sntp User's Manual"> 6258945Sroberto<meta name="generator" content="makeinfo 4.7"> 7258945Sroberto<link title="Top" rel="top" href="#Top"> 8258945Sroberto<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 9258945Sroberto<meta http-equiv="Content-Style-Type" content="text/css"> 10258945Sroberto<style type="text/css"><!-- 11258945Sroberto pre.display { font-family:inherit } 12258945Sroberto pre.format { font-family:inherit } 13258945Sroberto pre.smalldisplay { font-family:inherit; font-size:smaller } 14258945Sroberto pre.smallformat { font-family:inherit; font-size:smaller } 15258945Sroberto pre.smallexample { font-size:smaller } 16258945Sroberto pre.smalllisp { font-size:smaller } 17258945Sroberto span.sc { font-variant:small-caps } 18258945Sroberto span.roman { font-family: serif; font-weight: normal; } 19258945Sroberto--></style> 20258945Sroberto</head> 21258945Sroberto<body> 22258945Sroberto<h1 class="settitle">Sntp User's Manual</h1> 23258945Sroberto<div class="node"> 24258945Sroberto<p><hr> 25258945Sroberto<a name="Top"></a>Next: <a rel="next" accesskey="n" href="#sntp-Description">sntp Description</a>, 26258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#dir">(dir)</a>, 27258945SrobertoUp: <a rel="up" accesskey="u" href="#dir">(dir)</a> 28258945Sroberto<br> 29258945Sroberto</div> 30258945Sroberto 31258945Sroberto<h2 class="unnumbered">Simple Network Time Protocol User Manual</h2> 32258945Sroberto 33258945Sroberto<p>This document describes the use of the NTP Project's <code>sntp</code> program, 34258945Srobertothat can be used to query a Network Time Protocol (NTP) server and 35258945Srobertodisplay the time offset of the system clock relative to the server 36258945Srobertoclock. Run as root, it can correct the system clock to this offset as 37258945Srobertowell. It can be run as an interactive command or from a cron job. 38258945Sroberto 39258945Sroberto <p>This document applies to version 4.2.6p5 of <code>sntp</code>. 40258945Sroberto 41258945Sroberto <p>The program implements the SNTP protocol as defined by RFC 5905, the NTPv4 42258945SrobertoIETF specification. 43258945Sroberto 44258945Sroberto <div class="shortcontents"> 45258945Sroberto<h2>Short Contents</h2> 46258945Sroberto<ul> 47258945Sroberto<a href="#Top">Simple Network Time Protocol User Manual</a> 48258945Sroberto</ul> 49258945Sroberto</div> 50258945Sroberto 51258945Sroberto<ul class="menu"> 52258945Sroberto<li><a accesskey="1" href="#sntp-Description">sntp Description</a>: Description 53258945Sroberto<li><a accesskey="2" href="#sntp-Invocation">sntp Invocation</a>: Invoking sntp 54258945Sroberto<li><a accesskey="3" href="#Usage">Usage</a>: Usage 55258945Sroberto</ul> 56258945Sroberto 57258945Sroberto<div class="node"> 58258945Sroberto<p><hr> 59258945Sroberto<a name="sntp-Description"></a> 60258945Sroberto<br> 61258945Sroberto</div> 62258945Sroberto 63258945Sroberto<!-- node-name, next, previous, up --> 64258945Sroberto<h3 class="section">Description</h3> 65258945Sroberto 66258945Sroberto<p>By default, <code>sntp</code> writes the local data and time (i.e., not UTC) to the 67258945Srobertostandard output in the format: 68258945Sroberto 69258945Sroberto<pre class="example"> 1996 Oct 15 20:17:25.123 +4.567 +/- 0.089 secs 70258945Sroberto</pre> 71258945Sroberto <p>where the +4.567 +/- 0.089 secs indicates the time offset and 72258945Srobertoerror bound of the system clock relative to the server clock. 73258945Sroberto 74258945Sroberto<div class="node"> 75258945Sroberto<p><hr> 76258945Sroberto<a name="sntp-Invocation"></a> 77258945Sroberto<br> 78258945Sroberto</div> 79258945Sroberto 80258945Sroberto<h3 class="section">Invoking sntp</h3> 81258945Sroberto 82258945Sroberto<p><a name="index-sntp-1"></a><a name="index-standard-Simple-Network-Time-Protocol-program-2"></a> 83258945Sroberto<code>sntp</code> 84258945Srobertocan be used as a SNTP client to query a NTP or SNTP server and either display 85258945Srobertothe time or set the local system's time (given suitable privilege). It can be 86258945Srobertorun as an interactive command or in a 87258945Sroberto<code>cron</code> 88258945Srobertojob. 89258945Sroberto 90258945Sroberto <p>NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol) 91258945Srobertoare defined and described by RFC 5905. 92258945Sroberto 93258945Sroberto <p class="indent">The default is to write the estimated correct local date and time (i.e. not 94258945SrobertoUTC) to the standard output in a format like 95258945Sroberto<pre class="example"> 1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs 96258945Sroberto</pre> 97258945Sroberto <p>where the 98258945Sroberto<pre class="example"> +4.567 +/- 0.089 secs 99258945Sroberto</pre> 100258945Sroberto <p>indicates the local clock is 4.567 seconds behind the correct time 101258945Sroberto(so 4.567 seconds must be added to the local clock to get it to be correct), 102258945Srobertoand the (local) time of 103258945Sroberto<code>1996-10-15 20:17:25.123</code> 104258945Srobertocan be converted to UTC time by adding 8 hours and 0 minutes, and 105258945Srobertois believed to be correct to within 106258945Sroberto<code>+/- 0.089</code> 107258945Srobertoseconds. 108258945Sroberto 109258945Sroberto <p>This section was generated by <strong>AutoGen</strong>, 110258945Srobertothe 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. 111258945Sroberto 112258945Sroberto <p>This software is released under a specialized copyright license. 113258945Sroberto 114258945Sroberto<ul class="menu"> 115258945Sroberto<li><a accesskey="1" href="#sntp-usage">sntp usage</a>: sntp usage help (-?) 116258945Sroberto<li><a accesskey="2" href="#sntp-adjtime">sntp adjtime</a>: adjtime option (-j) 117258945Sroberto<li><a accesskey="3" href="#sntp-authentication">sntp authentication</a>: authentication option (-a) 118258945Sroberto<li><a accesskey="4" href="#sntp-broadcast">sntp broadcast</a>: broadcast option (-b) 119258945Sroberto<li><a accesskey="5" href="#sntp-ipv4">sntp ipv4</a>: ipv4 option (-4) 120258945Sroberto<li><a accesskey="6" href="#sntp-ipv6">sntp ipv6</a>: ipv6 option (-6) 121258945Sroberto<li><a accesskey="7" href="#sntp-keyfile">sntp keyfile</a>: keyfile option (-k) 122258945Sroberto<li><a accesskey="8" href="#sntp-kod">sntp kod</a>: kod option (-K) 123258945Sroberto<li><a accesskey="9" href="#sntp-logfile">sntp logfile</a>: logfile option (-l) 124258945Sroberto<li><a href="#sntp-normalverbose">sntp normalverbose</a>: normalverbose option (-d) 125258945Sroberto<li><a href="#sntp-settod">sntp settod</a>: settod option (-s) 126258945Sroberto<li><a href="#sntp-syslog">sntp syslog</a>: syslog option (-p) 127258945Sroberto<li><a href="#sntp-timeout">sntp timeout</a>: timeout option (-t) 128258945Sroberto</ul> 129258945Sroberto 130258945Sroberto<div class="node"> 131258945Sroberto<p><hr> 132258945Sroberto<a name="sntp-usage"></a>Next: <a rel="next" accesskey="n" href="#sntp-adjtime">sntp adjtime</a>, 133258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 134258945Sroberto<br> 135258945Sroberto</div> 136258945Sroberto 137258945Sroberto<h4 class="subsection">sntp usage help (-?)</h4> 138258945Sroberto 139258945Sroberto<p><a name="index-sntp-usage-3"></a> 140258945SrobertoThis is the automatically generated usage text for sntp: 141258945Sroberto 142258945Sroberto<pre class="example">sntp - standard Simple Network Time Protocol program - Ver. 4.2.6p5 143258945SrobertoUSAGE: sntp [ -<flag> [<val>] | --<name>[{=| }<val>] ]... \ 144258945Sroberto [ hostname-or-IP ...] 145258945Sroberto Flg Arg Option-Name Description 146258945Sroberto -4 no ipv4 Force IPv4 DNS name resolution 147258945Sroberto - prohibits these options: 148258945Sroberto ipv6 149258945Sroberto -6 no ipv6 Force IPv6 DNS name resolution 150258945Sroberto - prohibits these options: 151258945Sroberto ipv4 152258945Sroberto -d no normalverbose Normal verbose 153258945Sroberto -K Str kod KoD history filename 154258945Sroberto -p no syslog Logging with syslog 155258945Sroberto - prohibits these options: 156258945Sroberto logfile 157258945Sroberto -l Str logfile Log to specified logfile 158258945Sroberto - prohibits these options: 159258945Sroberto syslog 160258945Sroberto -s no settod Set (step) the time with settimeofday() 161258945Sroberto - prohibits these options: 162258945Sroberto adjtime 163258945Sroberto -j no adjtime Set (slew) the time with adjtime() 164258945Sroberto - prohibits these options: 165258945Sroberto settod 166258945Sroberto -b Str broadcast Use broadcasts to the address specified for synchronisation 167258945Sroberto -t Num timeout Specify the number of seconds to wait for broadcasts 168258945Sroberto -a Num authentication Enable authentication with the key auth-keynumber 169258945Sroberto -k Str keyfile Specify a keyfile. SNTP will look in this file for the key specified with -a 170258945Sroberto opt version Output version information and exit 171258945Sroberto -? no help Display extended usage information and exit 172258945Sroberto -! no more-help Extended usage information passed thru pager 173258945Sroberto -> opt save-opts Save the option state to a config file 174258945Sroberto -< Str load-opts Load options from a config file 175258945Sroberto - disabled as --no-load-opts 176258945Sroberto - may appear multiple times 177258945Sroberto 178258945SrobertoOptions are specified by doubled hyphens and their name or by a single 179258945Srobertohyphen and the flag character. 180258945Sroberto 181258945Sroberto 182258945Sroberto 183258945SrobertoThe following option preset mechanisms are supported: 184258945Sroberto - reading file $HOME/.ntprc 185258945Sroberto - reading file ./.ntprc 186258945Sroberto - examining environment variables named SNTP_* 187258945Sroberto 188258945Srobertosntp implements the Simple Network Time Protocol, and is used to query an 189258945SrobertoNTP or SNTP server and either display the time or set the local system's 190258945Srobertotime (given suitable privilege). 191258945Sroberto 192258945SrobertoIt can be run interactively from the command line or as a cron job. 193258945Sroberto 194258945SrobertoNTP and SNTP are defined by RFC 5905, which obsoletes RFC 4330 and RFC 195258945Sroberto1305. 196258945Sroberto 197258945Srobertoplease send bug reports to: http://bugs.ntp.org, bugs@ntp.org 198258945Sroberto</pre> 199258945Sroberto <div class="node"> 200258945Sroberto<p><hr> 201258945Sroberto<a name="sntp-adjtime"></a>Next: <a rel="next" accesskey="n" href="#sntp-authentication">sntp authentication</a>, 202258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-usage">sntp usage</a>, 203258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 204258945Sroberto<br> 205258945Sroberto</div> 206258945Sroberto 207258945Sroberto<h4 class="subsection">adjtime option (-j)</h4> 208258945Sroberto 209258945Sroberto<p><a name="index-sntp_002dadjtime-4"></a> 210258945SrobertoThis is the “set (slew) the time with adjtime()” option. 211258945Sroberto 212258945Sroberto <p>This option has some usage constraints. It: 213258945Sroberto <ul> 214258945Sroberto<li>must not appear in combination with any of the following options: 215258945Srobertosettod. 216258945Sroberto</ul> 217258945Sroberto 218258945Sroberto<div class="node"> 219258945Sroberto<p><hr> 220258945Sroberto<a name="sntp-authentication"></a>Next: <a rel="next" accesskey="n" href="#sntp-broadcast">sntp broadcast</a>, 221258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-adjtime">sntp adjtime</a>, 222258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 223258945Sroberto<br> 224258945Sroberto</div> 225258945Sroberto 226258945Sroberto<h4 class="subsection">authentication option (-a)</h4> 227258945Sroberto 228258945Sroberto<p><a name="index-sntp_002dauthentication-5"></a> 229258945SrobertoThis is the “enable authentication with the key auth-keynumber” option. 230258945SrobertoThis option enables authentication using the key specified in this option's argument. 231258945SrobertoThe argument of this option is the keyid, a number specified in the keyfile as this 232258945Srobertokey's identifier. See the keyfile option (-k) for more details. 233258945Sroberto 234258945Sroberto<div class="node"> 235258945Sroberto<p><hr> 236258945Sroberto<a name="sntp-broadcast"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv4">sntp ipv4</a>, 237258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-authentication">sntp authentication</a>, 238258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 239258945Sroberto<br> 240258945Sroberto</div> 241258945Sroberto 242258945Sroberto<h4 class="subsection">broadcast option (-b)</h4> 243258945Sroberto 244258945Sroberto<p><a name="index-sntp_002dbroadcast-6"></a> 245258945SrobertoThis is the “use broadcasts to the address specified for synchronisation” option. 246258945SrobertoIf specified SNTP will listen to the specified broadcast address 247258945Srobertofor NTP broadcasts. The default maximum wait time, 248258945Sroberto68 seconds, can be modified with -t. 249258945Sroberto 250258945Sroberto<div class="node"> 251258945Sroberto<p><hr> 252258945Sroberto<a name="sntp-ipv4"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv6">sntp ipv6</a>, 253258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-broadcast">sntp broadcast</a>, 254258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 255258945Sroberto<br> 256258945Sroberto</div> 257258945Sroberto 258258945Sroberto<h4 class="subsection">ipv4 option (-4)</h4> 259258945Sroberto 260258945Sroberto<p><a name="index-sntp_002dipv4-7"></a> 261258945SrobertoThis is the “force ipv4 dns name resolution” option. 262258945Sroberto 263258945Sroberto <p>This option has some usage constraints. It: 264258945Sroberto <ul> 265258945Sroberto<li>must not appear in combination with any of the following options: 266258945Srobertoipv6. 267258945Sroberto</ul> 268258945Sroberto 269258945Sroberto <p>Force DNS resolution of the following host names on the command line 270258945Srobertoto the IPv4 namespace. 271258945Sroberto 272258945Sroberto<div class="node"> 273258945Sroberto<p><hr> 274258945Sroberto<a name="sntp-ipv6"></a>Next: <a rel="next" accesskey="n" href="#sntp-keyfile">sntp keyfile</a>, 275258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-ipv4">sntp ipv4</a>, 276258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 277258945Sroberto<br> 278258945Sroberto</div> 279258945Sroberto 280258945Sroberto<h4 class="subsection">ipv6 option (-6)</h4> 281258945Sroberto 282258945Sroberto<p><a name="index-sntp_002dipv6-8"></a> 283258945SrobertoThis is the “force ipv6 dns name resolution” option. 284258945Sroberto 285258945Sroberto <p>This option has some usage constraints. It: 286258945Sroberto <ul> 287258945Sroberto<li>must not appear in combination with any of the following options: 288258945Srobertoipv4. 289258945Sroberto</ul> 290258945Sroberto 291258945Sroberto <p>Force DNS resolution of the following host names on the command line 292258945Srobertoto the IPv6 namespace. 293258945Sroberto 294258945Sroberto<div class="node"> 295258945Sroberto<p><hr> 296258945Sroberto<a name="sntp-keyfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-kod">sntp kod</a>, 297258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-ipv6">sntp ipv6</a>, 298258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 299258945Sroberto<br> 300258945Sroberto</div> 301258945Sroberto 302258945Sroberto<h4 class="subsection">keyfile option (-k)</h4> 303258945Sroberto 304258945Sroberto<p><a name="index-sntp_002dkeyfile-9"></a> 305258945SrobertoThis is the “specify a keyfile. sntp will look in this file for the key specified with -a” option. 306258945SrobertoThis option specifies the keyfile. SNTP will search for the key specified with -a keyno in this 307258945Srobertofile. Key files follow the following format: 308258945Sroberto 309258945Sroberto <p>keyid keytype key 310258945Sroberto 311258945Sroberto <p>Where keyid is a number identifying this key 312258945Srobertokeytype is one of the follow: 313258945SrobertoS Key in 64 Bit hexadecimal number as specified in in the DES specification. 314258945SrobertoN Key in 64 Bit hexadecimal number as specified in the NTP standard. 315258945SrobertoA Key in a 1-to-8 character ASCII string. 316258945SrobertoM Key in a 1-to-8 character ASCII string using the MD5 authentication scheme. 317258945Sroberto 318258945Sroberto <p>For more information see ntp.keys(5). 319258945Sroberto 320258945Sroberto<div class="node"> 321258945Sroberto<p><hr> 322258945Sroberto<a name="sntp-kod"></a>Next: <a rel="next" accesskey="n" href="#sntp-logfile">sntp logfile</a>, 323258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-keyfile">sntp keyfile</a>, 324258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 325258945Sroberto<br> 326258945Sroberto</div> 327258945Sroberto 328258945Sroberto<h4 class="subsection">kod option (-K)</h4> 329258945Sroberto 330258945Sroberto<p><a name="index-sntp_002dkod-10"></a> 331258945SrobertoThis is the “kod history filename” option. 332258945SrobertoSpecifies the filename to be used to persist the history of KoD 333258945Srobertoresponses received from servers. The default is 334258945Sroberto/var/db/ntp-kod. 335258945Sroberto 336258945Sroberto<div class="node"> 337258945Sroberto<p><hr> 338258945Sroberto<a name="sntp-logfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-normalverbose">sntp normalverbose</a>, 339258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-kod">sntp kod</a>, 340258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 341258945Sroberto<br> 342258945Sroberto</div> 343258945Sroberto 344258945Sroberto<h4 class="subsection">logfile option (-l)</h4> 345258945Sroberto 346258945Sroberto<p><a name="index-sntp_002dlogfile-11"></a> 347258945SrobertoThis is the “log to specified logfile” option. 348258945Sroberto 349258945Sroberto <p>This option has some usage constraints. It: 350258945Sroberto <ul> 351258945Sroberto<li>must not appear in combination with any of the following options: 352258945Srobertosyslog. 353258945Sroberto</ul> 354258945Sroberto 355258945Sroberto <p>This option causes the client to write log messages to the specified 356258945Srobertologfile. 357258945Sroberto 358258945Sroberto<div class="node"> 359258945Sroberto<p><hr> 360258945Sroberto<a name="sntp-normalverbose"></a>Next: <a rel="next" accesskey="n" href="#sntp-settod">sntp settod</a>, 361258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-logfile">sntp logfile</a>, 362258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 363258945Sroberto<br> 364258945Sroberto</div> 365258945Sroberto 366258945Sroberto<h4 class="subsection">normalverbose option (-d)</h4> 367258945Sroberto 368258945Sroberto<p><a name="index-sntp_002dnormalverbose-12"></a> 369258945SrobertoThis is the “normal verbose” option. 370258945SrobertoDiagnostic messages for non-fatal errors and a limited amount of 371258945Srobertotracing should be written to standard error. Fatal ones always 372258945Srobertoproduce a diagnostic. This option should be set when there is a 373258945Srobertosuspected problem with the server, network or the source. 374258945Sroberto 375258945Sroberto<div class="node"> 376258945Sroberto<p><hr> 377258945Sroberto<a name="sntp-settod"></a>Next: <a rel="next" accesskey="n" href="#sntp-syslog">sntp syslog</a>, 378258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-normalverbose">sntp normalverbose</a>, 379258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 380258945Sroberto<br> 381258945Sroberto</div> 382258945Sroberto 383258945Sroberto<h4 class="subsection">settod option (-s)</h4> 384258945Sroberto 385258945Sroberto<p><a name="index-sntp_002dsettod-13"></a> 386258945SrobertoThis is the “set (step) the time with settimeofday()” option. 387258945Sroberto 388258945Sroberto <p>This option has some usage constraints. It: 389258945Sroberto <ul> 390258945Sroberto<li>must not appear in combination with any of the following options: 391258945Srobertoadjtime. 392258945Sroberto</ul> 393258945Sroberto 394258945Sroberto<div class="node"> 395258945Sroberto<p><hr> 396258945Sroberto<a name="sntp-syslog"></a>Next: <a rel="next" accesskey="n" href="#sntp-timeout">sntp timeout</a>, 397258945SrobertoPrevious: <a rel="previous" accesskey="p" href="#sntp-settod">sntp settod</a>, 398258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 399258945Sroberto<br> 400258945Sroberto</div> 401258945Sroberto 402258945Sroberto<h4 class="subsection">syslog option (-p)</h4> 403258945Sroberto 404258945Sroberto<p><a name="index-sntp_002dsyslog-14"></a> 405258945SrobertoThis is the “logging with syslog” option. 406258945Sroberto 407258945Sroberto <p>This option has some usage constraints. It: 408258945Sroberto <ul> 409258945Sroberto<li>must not appear in combination with any of the following options: 410258945Srobertologfile. 411258945Sroberto</ul> 412258945Sroberto 413258945Sroberto <p>When this option is set all logging will be done using syslog. 414258945Sroberto 415258945Sroberto<div class="node"> 416258945Sroberto<p><hr> 417258945Sroberto<a name="sntp-timeout"></a>Previous: <a rel="previous" accesskey="p" href="#sntp-syslog">sntp syslog</a>, 418258945SrobertoUp: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 419258945Sroberto<br> 420258945Sroberto</div> 421258945Sroberto 422258945Sroberto<h4 class="subsection">timeout option (-t)</h4> 423258945Sroberto 424258945Sroberto<p><a name="index-sntp_002dtimeout-15"></a> 425258945SrobertoThis is the “specify the number of seconds to wait for broadcasts” option. 426258945SrobertoWhen waiting for a broadcast packet SNTP will wait the number 427258945Srobertoof seconds specified before giving up. Default 68 seconds. 428258945Sroberto 429258945Sroberto<div class="node"> 430258945Sroberto<p><hr> 431258945Sroberto<a name="Usage"></a> 432258945Sroberto<br> 433258945Sroberto</div> 434258945Sroberto 435258945Sroberto<!-- node-name, next, previous, up --> 436258945Sroberto<h3 class="section">Usage</h3> 437258945Sroberto 438258945Sroberto<p>The simplest use of this program is as an unprivileged command to 439258945Srobertocheck the current time, offset, and error in the local clock. 440258945SrobertoFor example: 441258945Sroberto 442258945Sroberto<pre class="example"> sntp ntpserver.somewhere 443258945Sroberto</pre> 444258945Sroberto <p>With suitable privilege, it can be run as a command or in a 445258945Sroberto<code>crom</code> job to reset the local clock from a reliable server, like 446258945Srobertothe <code>ntpdate</code> and <code>rdate</code> commands. 447258945SrobertoFor example: 448258945Sroberto 449258945Sroberto<pre class="example"> sntp -a ntpserver.somewhere 450258945Sroberto</pre> 451258945Sroberto </body></html> 452258945Sroberto 453