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Miscellaneous Options
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Miscellaneous Options
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<p><h4>Miscellaneous Commands</h4>

<dl>

<dt><code>broadcastdelay <i>seconds</i></code>
<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 local and remote servers. 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.

<p><dt><code>trap <i>host_address</i> [ port <i>port_number</i> ] [
interface <i>interface_address</i> ]</code>
<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><dd>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><dt><code>setvar <i>variable</i> [ default ]</code>
<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 <code><i>name</i> = <i>value</i></code> is
followed by the <code>default</code> keyword, the variable will be
listed as part of the default system variables (<code>ntpq rv</code>
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 <code>setvar</code> mechanism.

<p><dd>There are three special variables that contain the names of all
variable of the same group. The <code>sys_var_list</code> holds the
names of all system variables. The <code>peer_var_list</code> holds the
names of all peer variables and the <code>clock_var_list</code> holds
the names of the reference clock variables.

<p><dt><code>logfile <i>logfile</i></code>
<dd>This command specifies the location of an alternate log file to be
used instead of the default system <code>syslog</code> facility.

<p><dt><code>logconfig <i>configkeyword</i></code>
<dd>This command controls the amount and type of output written to the
system <code>syslog</code> facility or the alternate
<code>logfile</code> log file. By default, all output is turned on. All
<code><i>configkeyword</i></code> keywords can be prefixed with
<code>=</code>, <code>+</code> and <code>-</code>, where <code>=</code>
sets the <code>syslogmask</code>, <code>+</code> adds and <code>-</code>
removes messages. <code>syslog messages</code> can be controlled in four
classes (, <code>peer</code>, <code>sys</code> and <code>sync</code>).
Within these classes four types of messages can be controlled.

<p><dd>Informational messages (<code>info</code>) control configuration
information. Event messages (<code>events</code>) control logging of
events (reachability, synchronization, alarm conditions). Statistical
output is controlled with the <code>statistics</code> 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
<code>allprefix</code> can be used instead of a message class. A message
class may also be followed by the <code>all</code> keyword to
enable/disable all messages of the respective message class.

<p><dd>Thus, a minimal log configuration could look like this:

<p><dd><code>logconfig = syncstatus +sysevents</code>

<p><dd>This would just list the synchronizations state of
<code>xntpd</code> and the major system events. For a simple reference
server, the following minimum message configuration could be useful:

<p><dd><code>logconfig = syncall +clockall</code>

<p><dd>This configuration will list all clock information and
synchronization information. All other events and messages about peers,
system events and so on is suppressed.

</dl>

<p><h4>Variables</h4>

<p>Most variables used by the NTP protocol can be examined with the
<code>xntpdc</code> (mode 7 messages) and the <code>ntpq</code> (mode 6
messages). Currently, very few variables can be modified via mode 6
messages. These variables are either created with the
<code>setvar</code> directive or the leap warning bits. The leap warning
bits can be set in the <code>leapwarning</code> variable up to one month
ahead. Both the <code>leapwarning</code> and <code>leapindication</code>
variables have a slightly different encoding than the usual leap bits
interpretation:

<dl>

<dt><code>00</code>
<dd>The daemon passes the leap bits of its synchronization source (usual
mode of operation).

<p><dt><code>01/10</code>
<dd>A leap second is added/deleted (operator forced leap second).

<p><dt><code>11</code>
<dd>Leap information from the synchronizations source is ignored (thus
<code>LEAP_NOWARNING</code> is passed on).

</dl>

<hr><address>David L. Mills (mills@udel.edu)</address></body></html>
