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diff --git a/html/miscopt.htm b/html/miscopt.htm new file mode 100644 index 0000000..348bc3e --- /dev/null +++ b/html/miscopt.htm @@ -0,0 +1,279 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> +<html> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org"> +<title>Miscellaneous Options</title> +</head> +<body> +<h3>Miscellaneous Options</h3> + +<img align="left" src="pic/boom3.gif" alt="gif"><a href= +"http://www.eecis.udel.edu/~mills/pictures.htm">from <i>Pogo</i>, +Walt Kelly</a> + +<p>We have three, now looking for more.<br clear="left"> +</p> + +<hr> +<dl> +<dt><tt>broadcastdelay <i>seconds</i></tt></dt> + +<dd>The broadcast and multicast modes require a special calibration +to determine the network delay between the local and remote +servers. Ordinarily, this is done automatically by the initial +protocol exchanges between the client and server. In some cases, +the calibration procedure may fail due to network or server access +controls, for example. This command specifies the default delay to +be used under these circumstances. Typically (for Ethernet), a +number between 0.003 and 0.007 seconds is appropriate. The default +when this command is not used is 0.004 seconds.</dd> + +<dt><tt>driftfile <i>driftfile</i></tt></dt> + +<dd>This command specifies the name of the file used to record the +frequency offset of the local clock oscillator. If the file exists, +it is read at startup in order to set the initial frequency offset +and then updated once per hour with the current frequency offset +computed by the daemon. If the file does not exist or this command +is not given, the initial frequency offset is assumed zero. In this +case, it may take some hours for the frequency to stabilize and the +residual timing errors to subside. + +<p>The file format consists of a single line containing a single +floating point number, which records the frequency offset measured +in parts-per-million (PPM). The file is updated by first writing +the current drift value into a temporary file and then renaming +this file to replace the old version. This implies that <tt> +ntpd</tt> must have write permission for the directory the drift +file is located in, and that file system links, symbolic or +otherwise, should be avoided.</p> +</dd> + +<dt><tt>enable [auth | bclient | calibrate | kernel | monitor | ntp +| stats]</tt><br> +<tt>disable [auth | bclient | calibrate | kernel | monitor | ntp | +stats</tt></dt> + +<dd>Provides a way to enable or disable various server options. +Flags not mentioned are unaffected. Note that all of these flags +can be controlled remotely using the <a href="ntpdc.htm"><tt> +ntpdc</tt></a> utility program.</dd> + +<dd> +<dl> +<dt><tt>bclient</tt></dt> + +<dd>When enabled, this is identical to the <tt>broadcastclient</tt> +command. The default for this flag is <tt>disable</tt>.</dd> + +<dt><tt>calibrate</tt></dt> + +<dd>Enables the calibration facility, which automatically adjusts +the <tt>time1</tt> values for each clock driver to display the same +offset as the currently selected source or kernel discipline +signal. See the <a href="refclock.htm">Reference Clock Drivers</a> +for further information. The default for this flag is <tt> +disable</tt>.</dd> + +<dt><tt>kernel</tt></dt> + +<dd>Enables the precision-time kernel support for the <tt> +ntp_adjtime()</tt> system call, if implemented. Ordinarily, support +for this routine is detected automatically when the NTP daemon is +compiled, so it is not necessary for the user to worry about this +flag. It flag is provided primarily so that this support can be +disabled during kernel development. The default for this flag is +<tt>enable</tt>.</dd> + +<dt><tt>monitor</tt></dt> + +<dd>Enables the monitoring facility. See the <tt>ntpdc</tt> program +and the <tt>monlist</tt> command or further information. The +default for this flag is <tt>enable</tt>.</dd> + +<dt><tt>ntp</tt></dt> + +<dd>Enables the server to adjust its local clock by means of NTP. +If disabled, the local clock free-runs at its intrinsic time and +frequency offset. This flag is useful in case the local clock is +controlled by some other device or protocol and NTP is used only to +provide synchronization to other clients. In this case, the local +clock driver can be used to provide this function and also certain +time variables for error estimates and leap-indicators. See the <a +href="refclock.htm">Reference Clock Drivers</a> page for further +information. The default for this flag is <tt>enable</tt>.</dd> + +<dt><tt>stats</tt></dt> + +<dd>Enables the statistics facility. See the <a href="monopt.htm"> +Monitoring Options</a> page for further information. The default +for this flag is <tt>enable</tt>.</dd> +</dl> +</dd> + +<dt><tt>logconfig <i>configkeyword</i></tt></dt> + +<dd>This command controls the amount and type of output written to +the system <tt>syslog</tt> facility or the alternate <tt> +logfile</tt> log file. By default, all output is turned on. All <i> +<tt>configkeyword</tt></i> keywords can be prefixed with <tt> +=</tt>, <tt>+</tt> and <tt>-</tt>, where <tt>=</tt> sets the <tt> +syslogmask</tt>, <tt>+</tt> adds and <tt>-</tt> removes messages. +<tt>syslog messages</tt> can be controlled in four classes +(<tt>clock</tt>, <tt>peer</tt>, <tt>sys</tt> and <tt>sync</tt>). +Within these classes four types of messages can be controlled.</dd> + +<dd>Informational messages (<tt>info</tt>) control configuration +information. Event messages (<tt>events</tt>) control logging of +events (reachability, synchronization, alarm conditions). +Statistical output is controlled with the <tt>statistics</tt> +keyword. The final message group is the status messages. This +describes mainly the synchronizations status. Configuration +keywords are formed by concatenating the message class with the +event class. The <tt>all</tt> prefix can be used instead of a +message class. A message class may also be followed by the <tt> +all</tt> keyword to enable/disable all messages of the respective +message class.</dd> + +<dd>Thus, a minimal log configuration could look like this: + +<p><tt>logconfig=syncstatus +sysevents</tt></p> + +<p>This would just list the synchronizations state of <tt>ntpd</tt> +and the major system events. For a simple reference server, the +following minimum message configuration could be useful:</p> + +<p><tt>logconfig=syncall +clockall</tt></p> + +<p>This configuration will list all clock information and +synchronization information. All other events and messages about +peers, system events and so on is suppressed.</p> +</dd> + +<dt><tt>logfile <i>logfile</i></tt></dt> + +<dd>This command specifies the location of an alternate log file to +be used instead of the default system <tt>syslog</tt> +facility.</dd> + +<dt><tt>setvar <i>variable</i> [default]</tt></dt> + +<dd>This command adds an additional system variable. These +variables can be used to distribute additional information such as +the access policy. If the variable of the form <tt><i>name</i> = +<i>value</i></tt> is followed by the <tt>default</tt> keyword, the +variable will be listed as part of the default system variables +(<tt>ntpq rv</tt> command). These additional variables serve +informational purposes only. They are not related to the protocol +other that they can be listed. The known protocol variables will +always override any variables defined via the <tt>setvar</tt> +mechanism. There are three special variables that contain the names +of all variable of the same group. The <tt>sys_var_list</tt> holds +the names of all system variables. The <tt>peer_var_list</tt> holds +the names of all peer variables and the <tt>clock_var_list</tt> +holds the names of the reference clock variables.</dd> + +<dt><tt>tinker [ step <i>step</i> | panic <i>panic</i> | dispersion +<i>dispersion</i> | stepout <i>stepout</i> | minpoll <i>minpoll</i> +]</tt></dt> + +<dd>This command can be used to alter several system variables in +very exceptional circumstances. It should occur in the +configuration file before any other configuration options. The +default values of these variables have been carefully optimized for +a wide range of network speeds and reliability expectations. In +general, they interact in intricate ways that are hard to predict +and some combinations can result in some very nasty behavior. Very +rarely is it necessary to change the default values; but, some +folks can't resist twisting the knobs anyway and this command is +for them. Emphasis added: twisters are on their own and can expect +no help from the support group. + +<p>All arguments are in floating point seconds or seconds per +second. The <tt>minpoll</tt> argument is an integer in seconds to +the power of two. The variables operate as follows:</p> +</dd> + +<dd> +<dl> +<dt><tt>step <i>step</i></tt></dt> + +<dd>The argument becomes the new value for the step threshold, +normally 0.128 s. If set to zero, step adjustments will never +occur. In general, if the intent is only to avoid step adjustments, +the step threshold should be left alone and the <tt>-x</tt> command +line option be used instead.</dd> + +<dt><tt>panic <i>panic</i></tt></dt> + +<dd>The argument becomes the new value for the panic threshold, +normally 1000 s. If set to zero, the panic sanity check is disabled +and a clock offset of any value will be accepted.</dd> + +<dt><tt>dispersion <i>dispersion</i></tt></dt> + +<dd>The argument becomes the new value for the dispersion increase +rate, normally .000015.</dd> + +<dt><tt>stepout <i>stepout</i></tt></dt> + +<dd>The argument becomes the new value for the watchdog timeout, +normally 900 s.</dd> + +<dt><tt>minpoll <i>minpoll</i></tt></dt> + +<dd>The argument becomes the new value for the minimum poll +interval used when configuring multicast client, manycast client +and , symmetric passive mode association. The value defaults to 6 +(64 s) and has a lower limit of 4 (16 s).</dd> + +<dt><tt>allan <i>allan</i></tt></dt> + +<dd>The argument becomes the new value for the minimum Allan +intercept, which is a parameter of the PLL/FLL clock discipline +algorithm. The value defaults to 1024 s, which is also the lower +limit.</dd> + +<dt><tt>huffpuff <i>huffpuff</i></tt></dt> + +<dd>The argument becomes the new value for the experimental +huff-n'-puff filter span, which determines the most recent interval +the algorithm will search for a minimum delay. The lower limit is +900 s (15 m), but a more reasonable value is 7200 (2 hours). There +is no default, since the filter is not enabled unless this command +is given.</dd> +</dl> +</dd> + +<dt><tt>trap <i>host_address</i> [port <i>port_number</i>] +[interface <i>interface_address</i>]</tt></dt> + +<dd>This command configures a trap receiver at the given host +address and port number for sending messages with the specified +local interface address. If the port number is unspecified, a value +of 18447 is used. If the interface address is not specified, the +message is sent with a source address of the local interface the +message is sent through. Note that on a multihomed host the +interface used may vary from time to time with routing changes. + +<p>The trap receiver will generally log event messages and other +information from the server in a log file. While such monitor +programs may also request their own trap dynamically, configuring a +trap receiver will ensure that no messages are lost when the server +is started.</p> +</dd> +</dl> + +<h4>Files</h4> + +<tt>ntp.drift</tt> frequency compensation (PPM) + +<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> + |
