165 lines
6.9 KiB
HTML
165 lines
6.9 KiB
HTML
<!-- $NetBSD: xntpd.html,v 1.1 1998/12/30 20:20:37 mcr Exp $ -->
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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML Strict//EN">
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<html><head><title>
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xntpd - Network Time Protocol (NTP) daemon
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</title></head><body><h3>
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<code>xntpd</code> - Network Time Protocol (NTP) daemon
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</h3><hr>
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<p><h4>Synopsis</h4>
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<p><code>xntpd [ -aAbdm ] [ -c <i>conffile</i> ] [ -f
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<i>driftfile</i> ] [ -k <i>keyfile</i> ] [ -l <i>logfile</i> ] [
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-p <i>pidfile</i> ] [ -r <i>broadcastdelay</i> ] [ -s
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<i>statsdir</i> ] [ -t <i>key</i> ] [ -v <i>variable</i> ] [ -V
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<i>variable</i> ]</code>
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<p><h4>Description</h4>
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<p><code>xntpd</code> is an operating system daemon which sets and
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maintains the system time-of-day in synchronism with Internet
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standard time servers. <code>xntpd</code> is a complete
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implementation of the Network Time Protocol (NTP) version 3, as
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defined by RFC-1305, but also retains compatibility with version 1
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and 2 servers as defined by RFC- 1059 and RFC-1119,
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respectively. <code>xntpd</code> does all computations in 64-bit
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fixed point arithmetic and requires no floating point
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support. While the ultimate precision of this design, about 232
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picoseconds, is not achievable with ordinary workstations and
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networks of today, it may be required with future nanosecond CPU
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clocks and gigabit LANs.
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<p>The daemon can operate in any of several modes, including
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symmetric active/passive, client/server and broadcast/multicast,
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as described in RFC-1305. A broadcast/multicast client can
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discover remote servers, compute server-client propagation delay
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correction factors and configure itself automatically. This makes
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it possible to deploy a fleet of workstations without specifying
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configuration details specific to the local environment.
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<p>Ordinarily, <code>xntpd</code> reads the <code>ntp.conf</code>
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configuration file at startup time in order to determine the
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synchronization sources and operating modes. It is also possible
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to specify a working, although limited, configuration entirely on
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the command line, obviating the need for a configuration
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file. This may be particularly appropriate when the local host is
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to be configured as a broadcast or multicast client, with all
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peers being determined by listening to broadcasts at run time.
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<p>Various internal <code>xntpd</code> variables can be displayed
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and configuration options altered while the daemon is running
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using the <a href = "ntpq.html"> <code>ntpq</code></a> and <a href
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= "xntpdc.html"><code>xntpdc</code></a> utility programs.
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<p>When <code>xntpd</code> starts it looks at the value of
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<code>umask</code>, and if it's zero <code>xntpd</code> will set
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the <code>umask</code> to <code>022</code>.
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<p><h4>Command Line Options</h4>
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<dl>
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<dt><code>-a</code>
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<dd>Enable authentication mode. The default is enabled, so this option
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is obsolete now.
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<dt><code>-A</code>
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<dd>Disable authentication mode.
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<p><dt><code>-b</code>
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<dd>Synchronize using NTP broadcast messages.
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<p><dt><code>-c <i>conffile</i></code>
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<dd>Specify the name and path of the configuration file.
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<p><dt><code>-d</code>
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<dd>Specify debugging mode. This flag may occur multiple times, with
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each occurrence indicating greater detail of display.
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<p><dt><code>-f <i>driftfile</i></code>
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<dd>Specify the name and path of the drift file.
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<p><dt><code>-k <i>keyfile</i></code>
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<dd>Specify the name and path of the file containing the NTP
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authentication keys.
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<p><dt><code>-l <i>logfile</i></code>
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<dd>Specify the name and path of the log file. The default is the system
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log facility.
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<p><dt><code>-m</code>
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<dd>Synchronize using NTP multicast messages on the IP multicast group
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address 224.0.1.1 (requires multicast kernel).
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<p><dt><code>-p <i>pidfile</i></code>
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<dd>Specify the name and path to record the daemon's process ID.
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<p><dt><code>-r <i>broadcastdelay</i></code>
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<dd>Specify the default propagation delay from the broadcast/multicast
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server and this computer. This is used only if the delay cannot be
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computed automatically by the protocol.
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<p><dt><code>-s <i>statsdir</i></code>
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<dd>Specify the directory path for files created by the statistics
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facility.
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<p><dt><code>-t <i>key</i></code>
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<dd>Add a key number to the trusted key list.
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<p><dt><code>-v <i>variable</i></code>
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<dd>Add a system variable.
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<p><dt><code>-V <i>variable</i></code>
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<dd>Add a system variable listed by default.
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</dl>
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<p><h4>The Configuration File</h4>
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<p>The <code>xntpd</code> configuration file is read at initial startup
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in order to specify the synchronization sources, modes and other related
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information. Usually, it is installed in the <code>/etc</code>
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directory, but could be installed elsewhere (see the <code>-c
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<i>conffile</i></code> command line option). The file format is similar
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to other Unix configuration files - comments begin with a <code>#</code>
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character and extend to the end of the line; blank lines are ignored.
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Configuration commands consist of an initial keyword followed by a list
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of arguments, some of which may be optional, separated by whitespace.
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Commands may not be continued over multiple lines. Arguments may be host
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names, host addresses written in numeric, dotted-quad form, integers,
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floating point numbers (when specifying times in seconds) and text
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strings. Optional arguments are delimited by <code>[ ]</code> in the
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following descriptions, while alternatives are separated by
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<code>|</code>. The notation [ ... ] means an optional, indefinite
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repetition of the last item before the [ ... ].
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<p>See the following pages for configuration and control options. While
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there is a rich set of options available, the only required option is
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one or more <code>server, peer</code> or <code>broadcast</code> commands
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described in the Configuration Options page. The <a href = "notes.html">
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Notes on Configuring NTP and Setting up a NTP Subnet </a> page contains
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an extended discussion of these options.
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<p><a href="confopt.html"> Configuration Options </a>
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<br><a href="authopt.html"> Authentication Options </a>
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<br><a href="monopt.html"> Monitoring Options </a>
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<br><a href="accopt.html"> Access Control Options </a>
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<br><a href="clockopt.html"> Reference Clock Options </a>
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<br><a href="miscopt.html"> Miscellaneous Options </a>
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<p><h4>Files</h4>
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<p><code>/etc/ntp.conf</code> - the default name of the configuration
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file
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<br><code>/etc/ntp.drift</code> - the default name of the drift file
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<br><code>/etc/ntp.keys</code> - the default name of the key file
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<p><h4>Bugs</h4>
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<p><code>xntpd</code> has gotten rather fat. While not huge, it has gotten
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larger than might be desireable for an elevated-priority daemon running
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on a workstation, particularly since many of the fancy features which
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consume the space were designed more with a busy primary server, rather
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than a high stratum workstation, in mind.
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<hr><address>David L. Mills (mills@udel.edu)</address></body></html>
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