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diff --git a/html/ntpdate.htm b/html/ntpdate.htm deleted file mode 100644 index c2d32bb25856..000000000000 --- a/html/ntpdate.htm +++ /dev/null @@ -1,186 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> -<html> -<head> -<meta name="generator" content="HTML Tidy, see www.w3.org"> -<title>ntpdate - set the date and time via NTP</title> -</head> -<body> -<h3><tt>ntpdate</tt> - set the date and time via NTP</h3> - -<img align="left" src="pic/rabbit.gif" alt="gif"><a href= -"http://www.eecis.udel.edu/~mills/pictures.htm">from <i>Alice's -Adventures in Wonderland</i>, Lewis Carroll</a> - -<p>I told you it was eyeball and wristwatch.<br clear="left"> -</p> - -<hr> -<p>Disclaimer: The functionality of this program is now available -in the <tt>ntpd</tt> program. See the <tt>-q</tt> command line -option in the <a href="ntpd.htm"><tt>ntpd</tt> - Network Time -Protocol (NTP) daemon</a> page. After a suitable period of -mourning, the <tt>ntpdate</tt> program is to be retired from this -distribution</p> - -<h4>Synopsis</h4> - -<tt>ntpdate [ -bBdoqsuv ] [ -a <i>key</i> ] [ -e <i>authdelay</i> ] -[ -k <i>keyfile</i> ] [ -o <i>version</i> ] [ -p <i>samples</i> ] [ --t <i>timeout</i> ] <i>server</i> [ ... ]</tt> - -<h4>Description</h4> - -<tt>ntpdate</tt> sets the local date and time by polling the -Network Time Protocol (NTP) server(s) given as the <i>server</i> -arguments to determine the correct time. It must be run as root on -the local host. A number of samples are obtained from each of the -servers specified and a subset of the NTP clock filter and -selection algorithms are applied to select the best of these. Note -that the accuracy and reliability of <tt>ntpdate</tt> depends on -the number of servers, the number of polls each time it is run and -the interval between runs. - -<p><tt>ntpdate</tt> can be run manually as necessary to set the -host clock, or it can be run from the host startup script to set -the clock at boot time. This is useful in some cases to set the -clock initially before starting the NTP daemon <tt>ntpd</tt>. It is -also possible to run <tt>ntpdate</tt> from a <tt>cron</tt> script. -However, it is important to note that <tt>ntpdate</tt> with -contrived <tt>cron</tt> scripts is no substitute for the NTP -daemon, which uses sophisticated algorithms to maximize accuracy -and reliability while minimizing resource use. Finally, since <tt> -ntpdate</tt> does not discipline the host clock frequency as does -<tt>ntpd</tt>, the accuracy using <tt>ntpdate</tt> is limited.</p> - -<p>Time adjustments are made by <tt>ntpdate</tt> in one of two -ways. If <tt>ntpdate</tt> determines the clock is in error more -than 0.5 second it will simply step the time by calling the system -<tt>settimeofday()</tt> routine. If the error is less than 0.5 -seconds, it will slew the time by calling the system <tt> -adjtime()</tt> routine. The latter technique is less disruptive and -more accurate when the error is small, and works quite well when -<tt>ntpdate</tt> is run by <tt>cron</tt> every hour or two.</p> - -<p><tt>ntpdate</tt> will decline to set the date if an NTP server -daemon (e.g., <tt>ntpd</tt>) is running on the same host. When -running <tt>ntpdate</tt> on a regular basis from <tt>cron</tt> as -an alternative to running a daemon, doing so once every hour or two -will result in precise enough timekeeping to avoid stepping the -clock.</p> - -<p>If NetInfo support is compiled into <tt>ntpdate</tt>, then the -<tt>server</tt> argument is optional if <tt>ntpdate</tt> can find a -time server in the NetInfo configuration for <tt>ntpd</tt>.</p> - -<h4>Command Line Options</h4> - -<dl> -<dt><tt>-a <i>key</i></tt></dt> - -<dd>Enable the authentication function and specify the key -identifier to be used for authentication as the argument <i> -key</i><tt>ntpdate</tt>. The keys and key identifiers must match in -both the client and server key files. The default is to disable the -authentication function.</dd> - -<dt><tt>-B</tt></dt> - -<dd>Force the time to always be slewed using the adjtime() system -call, even if the measured offset is greater than +-128 ms. The -default is to step the time using settimeofday() if the offset is -greater than +-128 ms. Note that, if the offset is much greater -than +-128 ms in this case, that it can take a long time (hours) to -slew the clock to the correct value. During this time. the host -should not be used to synchronize clients.</dd> - -<dt><tt>-b</tt></dt> - -<dd>Force the time to be stepped using the settimeofday() system -call, rather than slewed (default) using the adjtime() system call. -This option should be used when called from a startup file at boot -time.</dd> - -<dt><tt>-d</tt></dt> - -<dd>Enable the debugging mode, in which <tt>ntpdate</tt> will go -through all the steps, but not adjust the local clock. Information -useful for general debugging will also be printed.</dd> - -<dt><tt>-e <i>authdelay</i></tt></dt> - -<dd>Specify the processing delay to perform an authentication -function as the value <i>authdelay</i>, in seconds and fraction -(see <tt>ntpd</tt> for details). This number is usually small -enough to be negligible for most purposes, though specifying a -value may improve timekeeping on very slow CPU's.</dd> - -<dt><tt>-k <i>keyfile</i></tt></dt> - -<dd>Specify the path for the authentication key file as the string -<i>keyfile</i>. The default is <tt>/etc/ntp.keys</tt>. This file -should be in the format described in <tt>ntpd</tt>.</dd> - -<dt><tt>-o <i>version</i></tt></dt> - -<dd>Specify the NTP version for outgoint packets as the integer <i> -version</i>, which can be 1 or 2. The default is 3. This allows -<tt>ntpdate</tt> to be used with older NTP versions.</dd> - -<dt><tt>-p <i>samples</i></tt></dt> - -<dd>Specify the number of samples to be acquired from each server -as the integer <i>samples</i>, with values from 1 to 8 inclusive. -The default is 4.</dd> - -<dt><i><tt>-q</tt></i></dt> - -<dd>Query only - don't set the clock.</dd> - -<dt><tt>-s</tt></dt> - -<dd>Divert logging output from the standard output (default) to the -system <tt>syslog</tt> facility. This is designed primarily for -convenience of <tt>cron</tt> scripts.</dd> - -<dt><tt>-t <i>timeout</i></tt></dt> - -<dd>Specify the maximum time waiting for a server response as the -value <i>timeout</i>, in seconds and fraction. The value is is -rounded to a multiple of 0.2 seconds. The default is 1 second, a -value suitable for polling across a LAN.</dd> - -<dt><tt>-u</tt></dt> - -<dd>Direct <tt>ntpdate</tt> to use an unprivileged port or outgoing -packets. This is most useful when behind a firewall that blocks -incoming traffic to privileged ports, and you want to synchronise -with hosts beyond the firewall. Note that the <tt>-d</tt> option -always uses unprivileged ports.</dd> - -<dt><tt>-<i>v</i></tt></dt> - -<dd>Be verbose. This option will cause <tt>ntpdate</tt>'s version -identification string to be logged.</dd> -</dl> - -<h4>Files</h4> - -<tt>/etc/ntp.keys</tt> - encryption keys used by <tt>ntpdate</tt>. - -<h4>Bugs</h4> - -The slew adjustment is actually 50% larger than the measured -offset, since this (it is argued) will tend to keep a badly -drifting clock more accurate. This is probably not a good idea and -may cause a troubling hunt for some values of the kernel variables -<tt>tick</tt> and <tt>tickadj</tt>. - -<hr> -<a href="index.htm"><img align="left" src="pic/home.gif" alt= -"gif"></a> - -<address><a href="mailto:mills@udel.edu">David L. Mills -<mills@udel.edu></a></address> -</body> -</html> - |