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diff --git a/sntp/sntp.html b/sntp/sntp.html new file mode 100644 index 0000000..b043f40 --- /dev/null +++ b/sntp/sntp.html @@ -0,0 +1,452 @@ +<html lang="en"> +<head> +<title>Sntp User's Manual</title> +<meta http-equiv="Content-Type" content="text/html"> +<meta name="description" content="Sntp User's Manual"> +<meta name="generator" content="makeinfo 4.7"> +<link title="Top" rel="top" href="#Top"> +<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> +<meta http-equiv="Content-Style-Type" content="text/css"> +<style type="text/css"><!-- + pre.display { font-family:inherit } + pre.format { font-family:inherit } + pre.smalldisplay { font-family:inherit; font-size:smaller } + pre.smallformat { font-family:inherit; font-size:smaller } + pre.smallexample { font-size:smaller } + pre.smalllisp { font-size:smaller } + span.sc { font-variant:small-caps } + span.roman { font-family: serif; font-weight: normal; } +--></style> +</head> +<body> +<h1 class="settitle">Sntp User's Manual</h1> +<div class="node"> +<p><hr> +<a name="Top"></a>Next: <a rel="next" accesskey="n" href="#sntp-Description">sntp Description</a>, +Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>, +Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> +<br> +</div> + +<h2 class="unnumbered">Simple Network Time Protocol User Manual</h2> + +<p>This document describes the use of the NTP Project's <code>sntp</code> program, +that can be used to query a Network Time Protocol (NTP) server and +display the time offset of the system clock relative to the server +clock. Run as root, it can correct the system clock to this offset as +well. It can be run as an interactive command or from a cron job. + + <p>This document applies to version 4.2.6p5 of <code>sntp</code>. + + <p>The program implements the SNTP protocol as defined by RFC 5905, the NTPv4 +IETF specification. + + <div class="shortcontents"> +<h2>Short Contents</h2> +<ul> +<a href="#Top">Simple Network Time Protocol User Manual</a> +</ul> +</div> + +<ul class="menu"> +<li><a accesskey="1" href="#sntp-Description">sntp Description</a>: Description +<li><a accesskey="2" href="#sntp-Invocation">sntp Invocation</a>: Invoking sntp +<li><a accesskey="3" href="#Usage">Usage</a>: Usage +</ul> + +<div class="node"> +<p><hr> +<a name="sntp-Description"></a> +<br> +</div> + +<!-- node-name, next, previous, up --> +<h3 class="section">Description</h3> + +<p>By default, <code>sntp</code> writes the local data and time (i.e., not UTC) to the +standard output in the format: + +<pre class="example"> 1996 Oct 15 20:17:25.123 +4.567 +/- 0.089 secs +</pre> + <p>where the +4.567 +/- 0.089 secs indicates the time offset and +error bound of the system clock relative to the server clock. + +<div class="node"> +<p><hr> +<a name="sntp-Invocation"></a> +<br> +</div> + +<h3 class="section">Invoking sntp</h3> + +<p><a name="index-sntp-1"></a><a name="index-standard-Simple-Network-Time-Protocol-program-2"></a> +<code>sntp</code> +can be used as a SNTP client to query a NTP or SNTP server and either display +the time or set the local system's time (given suitable privilege). It can be +run as an interactive command or in a +<code>cron</code> +job. + + <p>NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol) +are defined and described by RFC 5905. + + <p class="indent">The default is to write the estimated correct local date and time (i.e. not +UTC) to the standard output in a format like +<pre class="example"> 1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs +</pre> + <p>where the +<pre class="example"> +4.567 +/- 0.089 secs +</pre> + <p>indicates the local clock is 4.567 seconds behind the correct time +(so 4.567 seconds must be added to the local clock to get it to be correct), +and the (local) time of +<code>1996-10-15 20:17:25.123</code> +can be converted to UTC time by adding 8 hours and 0 minutes, and +is believed to be correct to within +<code>+/- 0.089</code> +seconds. + + <p>This section was generated by <strong>AutoGen</strong>, +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. + + <p>This software is released under a specialized copyright license. + +<ul class="menu"> +<li><a accesskey="1" href="#sntp-usage">sntp usage</a>: sntp usage help (-?) +<li><a accesskey="2" href="#sntp-adjtime">sntp adjtime</a>: adjtime option (-j) +<li><a accesskey="3" href="#sntp-authentication">sntp authentication</a>: authentication option (-a) +<li><a accesskey="4" href="#sntp-broadcast">sntp broadcast</a>: broadcast option (-b) +<li><a accesskey="5" href="#sntp-ipv4">sntp ipv4</a>: ipv4 option (-4) +<li><a accesskey="6" href="#sntp-ipv6">sntp ipv6</a>: ipv6 option (-6) +<li><a accesskey="7" href="#sntp-keyfile">sntp keyfile</a>: keyfile option (-k) +<li><a accesskey="8" href="#sntp-kod">sntp kod</a>: kod option (-K) +<li><a accesskey="9" href="#sntp-logfile">sntp logfile</a>: logfile option (-l) +<li><a href="#sntp-normalverbose">sntp normalverbose</a>: normalverbose option (-d) +<li><a href="#sntp-settod">sntp settod</a>: settod option (-s) +<li><a href="#sntp-syslog">sntp syslog</a>: syslog option (-p) +<li><a href="#sntp-timeout">sntp timeout</a>: timeout option (-t) +</ul> + +<div class="node"> +<p><hr> +<a name="sntp-usage"></a>Next: <a rel="next" accesskey="n" href="#sntp-adjtime">sntp adjtime</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">sntp usage help (-?)</h4> + +<p><a name="index-sntp-usage-3"></a> +This is the automatically generated usage text for sntp: + +<pre class="example">sntp - standard Simple Network Time Protocol program - Ver. 4.2.6p5 +USAGE: sntp [ -<flag> [<val>] | --<name>[{=| }<val>] ]... \ + [ hostname-or-IP ...] + Flg Arg Option-Name Description + -4 no ipv4 Force IPv4 DNS name resolution + - prohibits these options: + ipv6 + -6 no ipv6 Force IPv6 DNS name resolution + - prohibits these options: + ipv4 + -d no normalverbose Normal verbose + -K Str kod KoD history filename + -p no syslog Logging with syslog + - prohibits these options: + logfile + -l Str logfile Log to specified logfile + - prohibits these options: + syslog + -s no settod Set (step) the time with settimeofday() + - prohibits these options: + adjtime + -j no adjtime Set (slew) the time with adjtime() + - prohibits these options: + settod + -b Str broadcast Use broadcasts to the address specified for synchronisation + -t Num timeout Specify the number of seconds to wait for broadcasts + -a Num authentication Enable authentication with the key auth-keynumber + -k Str keyfile Specify a keyfile. SNTP will look in this file for the key specified with -a + opt version Output version information and exit + -? no help Display extended usage information and exit + -! no more-help Extended usage information passed thru pager + -> opt save-opts Save the option state to a config file + -< Str load-opts Load options from a config file + - disabled as --no-load-opts + - may appear multiple times + +Options are specified by doubled hyphens and their name or by a single +hyphen and the flag character. + + + +The following option preset mechanisms are supported: + - reading file $HOME/.ntprc + - reading file ./.ntprc + - examining environment variables named SNTP_* + +sntp implements the Simple Network Time Protocol, and is used to query an +NTP or SNTP server and either display the time or set the local system's +time (given suitable privilege). + +It can be run interactively from the command line or as a cron job. + +NTP and SNTP are defined by RFC 5905, which obsoletes RFC 4330 and RFC +1305. + +please send bug reports to: http://bugs.ntp.org, bugs@ntp.org +</pre> + <div class="node"> +<p><hr> +<a name="sntp-adjtime"></a>Next: <a rel="next" accesskey="n" href="#sntp-authentication">sntp authentication</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-usage">sntp usage</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">adjtime option (-j)</h4> + +<p><a name="index-sntp_002dadjtime-4"></a> +This is the “set (slew) the time with adjtime()” option. + + <p>This option has some usage constraints. It: + <ul> +<li>must not appear in combination with any of the following options: +settod. +</ul> + +<div class="node"> +<p><hr> +<a name="sntp-authentication"></a>Next: <a rel="next" accesskey="n" href="#sntp-broadcast">sntp broadcast</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-adjtime">sntp adjtime</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">authentication option (-a)</h4> + +<p><a name="index-sntp_002dauthentication-5"></a> +This is the “enable authentication with the key auth-keynumber” option. +This option enables authentication using the key specified in this option's argument. +The argument of this option is the keyid, a number specified in the keyfile as this +key's identifier. See the keyfile option (-k) for more details. + +<div class="node"> +<p><hr> +<a name="sntp-broadcast"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv4">sntp ipv4</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-authentication">sntp authentication</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">broadcast option (-b)</h4> + +<p><a name="index-sntp_002dbroadcast-6"></a> +This is the “use broadcasts to the address specified for synchronisation” option. +If specified SNTP will listen to the specified broadcast address +for NTP broadcasts. The default maximum wait time, +68 seconds, can be modified with -t. + +<div class="node"> +<p><hr> +<a name="sntp-ipv4"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv6">sntp ipv6</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-broadcast">sntp broadcast</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">ipv4 option (-4)</h4> + +<p><a name="index-sntp_002dipv4-7"></a> +This is the “force ipv4 dns name resolution” option. + + <p>This option has some usage constraints. It: + <ul> +<li>must not appear in combination with any of the following options: +ipv6. +</ul> + + <p>Force DNS resolution of the following host names on the command line +to the IPv4 namespace. + +<div class="node"> +<p><hr> +<a name="sntp-ipv6"></a>Next: <a rel="next" accesskey="n" href="#sntp-keyfile">sntp keyfile</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-ipv4">sntp ipv4</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">ipv6 option (-6)</h4> + +<p><a name="index-sntp_002dipv6-8"></a> +This is the “force ipv6 dns name resolution” option. + + <p>This option has some usage constraints. It: + <ul> +<li>must not appear in combination with any of the following options: +ipv4. +</ul> + + <p>Force DNS resolution of the following host names on the command line +to the IPv6 namespace. + +<div class="node"> +<p><hr> +<a name="sntp-keyfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-kod">sntp kod</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-ipv6">sntp ipv6</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">keyfile option (-k)</h4> + +<p><a name="index-sntp_002dkeyfile-9"></a> +This is the “specify a keyfile. sntp will look in this file for the key specified with -a” option. +This option specifies the keyfile. SNTP will search for the key specified with -a keyno in this +file. Key files follow the following format: + + <p>keyid keytype key + + <p>Where keyid is a number identifying this key +keytype is one of the follow: +S Key in 64 Bit hexadecimal number as specified in in the DES specification. +N Key in 64 Bit hexadecimal number as specified in the NTP standard. +A Key in a 1-to-8 character ASCII string. +M Key in a 1-to-8 character ASCII string using the MD5 authentication scheme. + + <p>For more information see ntp.keys(5). + +<div class="node"> +<p><hr> +<a name="sntp-kod"></a>Next: <a rel="next" accesskey="n" href="#sntp-logfile">sntp logfile</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-keyfile">sntp keyfile</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">kod option (-K)</h4> + +<p><a name="index-sntp_002dkod-10"></a> +This is the “kod history filename” option. +Specifies the filename to be used to persist the history of KoD +responses received from servers. The default is +/var/db/ntp-kod. + +<div class="node"> +<p><hr> +<a name="sntp-logfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-normalverbose">sntp normalverbose</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-kod">sntp kod</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">logfile option (-l)</h4> + +<p><a name="index-sntp_002dlogfile-11"></a> +This is the “log to specified logfile” option. + + <p>This option has some usage constraints. It: + <ul> +<li>must not appear in combination with any of the following options: +syslog. +</ul> + + <p>This option causes the client to write log messages to the specified +logfile. + +<div class="node"> +<p><hr> +<a name="sntp-normalverbose"></a>Next: <a rel="next" accesskey="n" href="#sntp-settod">sntp settod</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-logfile">sntp logfile</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">normalverbose option (-d)</h4> + +<p><a name="index-sntp_002dnormalverbose-12"></a> +This is the “normal verbose” option. +Diagnostic messages for non-fatal errors and a limited amount of +tracing should be written to standard error. Fatal ones always +produce a diagnostic. This option should be set when there is a +suspected problem with the server, network or the source. + +<div class="node"> +<p><hr> +<a name="sntp-settod"></a>Next: <a rel="next" accesskey="n" href="#sntp-syslog">sntp syslog</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-normalverbose">sntp normalverbose</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">settod option (-s)</h4> + +<p><a name="index-sntp_002dsettod-13"></a> +This is the “set (step) the time with settimeofday()” option. + + <p>This option has some usage constraints. It: + <ul> +<li>must not appear in combination with any of the following options: +adjtime. +</ul> + +<div class="node"> +<p><hr> +<a name="sntp-syslog"></a>Next: <a rel="next" accesskey="n" href="#sntp-timeout">sntp timeout</a>, +Previous: <a rel="previous" accesskey="p" href="#sntp-settod">sntp settod</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">syslog option (-p)</h4> + +<p><a name="index-sntp_002dsyslog-14"></a> +This is the “logging with syslog” option. + + <p>This option has some usage constraints. It: + <ul> +<li>must not appear in combination with any of the following options: +logfile. +</ul> + + <p>When this option is set all logging will be done using syslog. + +<div class="node"> +<p><hr> +<a name="sntp-timeout"></a>Previous: <a rel="previous" accesskey="p" href="#sntp-syslog">sntp syslog</a>, +Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> +<br> +</div> + +<h4 class="subsection">timeout option (-t)</h4> + +<p><a name="index-sntp_002dtimeout-15"></a> +This is the “specify the number of seconds to wait for broadcasts” option. +When waiting for a broadcast packet SNTP will wait the number +of seconds specified before giving up. Default 68 seconds. + +<div class="node"> +<p><hr> +<a name="Usage"></a> +<br> +</div> + +<!-- node-name, next, previous, up --> +<h3 class="section">Usage</h3> + +<p>The simplest use of this program is as an unprivileged command to +check the current time, offset, and error in the local clock. +For example: + +<pre class="example"> sntp ntpserver.somewhere +</pre> + <p>With suitable privilege, it can be run as a command or in a +<code>crom</code> job to reset the local clock from a reliable server, like +the <code>ntpdate</code> and <code>rdate</code> commands. +For example: + +<pre class="example"> sntp -a ntpserver.somewhere +</pre> + </body></html> + |
