1 files changed, 185 insertions, 0 deletions
diff --git a/contrib/ntp/html/ntpdate.htm b/contrib/ntp/html/ntpdate.htm
new file mode 100644
index 000000000000..a7f532fef0e5
--- /dev/null
+++ b/contrib/ntp/html/ntpdate.htm
@@ -0,0 +1,185 @@
+<HTML>
+<HEAD>
+   <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
+   <META NAME="GENERATOR" CONTENT="Mozilla/4.01 [en] (Win95; I) [Netscape]">
+   <TITLE>ntpdate - set the date and time via NTP
+</TITLE>
+</HEAD>
+<BODY>
+
+<H3>
+<TT>ntpdate</TT> - set the date and time via NTP</H3>
+
+<HR>
+<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>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><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>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>.
+
+<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>.&nbsp;
+<HR>
+<ADDRESS>
+David L. Mills (mills@udel.edu)</ADDRESS>
+
+</BODY>
+</HTML>