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ntpq - standard NTP query program
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<code>ntpq</code> - standard NTP query program
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<p><h4>Synopsis</h4>

<p><code>ntpq [ -inp ] [ -c <i>command</i> ] [ <i>host</i> ] [ ... ]</code>
<p><h4>Description</h4>

<p><code>ntpq</code> is used to query NTP servers which implement the
recommended NTP mode 6 control message format about current state and to
request changes in that state. The program may be run either in
interactive mode or controlled using command line arguments. Requests to
read and write arbitrary variables can be assembled, with raw and
pretty-printed output options being available. <code>ntpq</code> can
also obtain and print a list of peers in a common format by sending
multiple queries to the server.

<p>If one or more request options is included on the command line when
<code>ntpq</code> is executed, each of the requests will be sent to the
NTP servers running on each of the hosts given as command line
arguments, or on localhost by default. If no request options are given,
<code>ntpq</code> will attempt to read commands from the standard input
and execute these on the NTP server running on the first host given on
the command line, again defaulting to localhost when no other host is
specified. <code>ntpq</code> will prompt for commands if the standard
input is a terminal device.

<p><code>ntpq</code> uses NTP mode 6 packets to communicate with the NTP
server, and hence can be used to query any compatable server on the
network which permits it. Note that since NTP is a UDP protocol this
communication will be somewhat unreliable, especially over large
distances in terms of network topology. <code>ntpq</code> makes one
attempt to retransmit requests, and will time requests out if the remote
host is not heard from within a suitable timeout time.

<p>Command line options are described following. Specifying a command
line option other than -i or -n will cause the specified query (queries)
to be sent to the indicated host(s) immediately. Otherwise,
<code>ntpq</code> will attempt to read interactive format commands from
the standard input.

<dl>

<dt><code>-c</code>
<dd>The following argument is interpreted as an interactive format
command and is added to the list of commands to be executed on the
specified host(s). Multiple -c options may be given.

<p><dt><code>-i</code>
<dd>Force <code>ntpq</code> to operate in interactive mode. Prompts will
be written to the standard output and commands read from the standard
input.

<p><dt><code>-n</code>
<dd>Output all host addresses in dotted-quad numeric format rather than
converting to the canonical host names.

<p><dt><code>-p</code>
<dd>Print a list of the peers known to the server as well as a summary
of their state. This is equivalent to the <code>peers</code> interactive
command.

</dl>
<p><h4>Internal Commands</h4>

<p>Interactive format commands consist of a keyword followed by zero to
four arguments. Only enough characters of the full keyword to uniquely
identify the command need be typed. The output of a command is normally
sent to the standard output, but optionally the output of individual
commands may be sent to a file by appending a "&lt;", followed by a file
name, to the command line. A number of interactive format commands are
executed entirely within the <code>ntpq</code> program itself and do not
result in NTP mode 6 requests being sent to a server. These are
described following.

<dl>

<dt><code>? [ <i>command_keyword</i> ]</code>
<br><code>helpl [ <i>command_keyword</i> ]</code>
<dd>A <code>"?"</code> by itself will print a list of all the command
keywords known to this incarnation of <code>ntpq</code>. A
<code>"?"</code> followed by a command keyword will print funcation and
usage information about the command. This command is probably a better
source of information about <code>ntpq</code> than this manual page.

<p><dt><code>addvars <i>variable_name</i> [ = <i>value</i> ] [ ...
]</code>
<br><code>rmvars <i>variable_name</i> [ ... ]</code>
<br><code>clearvars</code>
<dd>The data carried by NTP mode 6 messages consists of a list of items
of the form <code><i>variable_name</i> = <i>value</i></code>, where the
<code>" = <i>value</i>"</code> is ignored, and can be omitted, in
requests to the server to read variables. <code>ntpq</code> maintains an
internal list in which data to be included in control messages can be
assembled, and sent using the readlist and writelist commands described
below. The addvars command allows variables and their optional values to
be added to the list. If more than one variable is to be added, the list
should be comma-separated and not contain white space. The rmvars
command can be used to remove individual variables from the list, while
the clearlist command removes all variables from the list.

<p><dt><code>authenticate yes | no</code>
<dd>Normally <code>ntpq</code> does not authenticate requests unless
they are write requests. The command authenticate yes causes
<code>ntpq</code> to send authentication with all requests it makes.
Authenticated requests causes some servers to handle requests slightly
differently, and can occasionally melt the CPU in fuzzballs if you turn
authentication on before doing a peer display.

<p><dt><code>cooked</code>
<dd>Causes output from query commands to be <code>"cooked"</code>.
Variables which are recognized by the server will have their values
reformatted for human consumption. Variables which <code>ntpq</code>
thinks should have a decodeable value but didn't are marked with a
trailing <code>"?"</code>.

<p><dt><code>debug more | less | off</code>
<dd>Turns internal query program debugging on and off.

<p><dt><code>delay <i>milliseconds</i></code>
<dd>Specify a time interval to be added to timestamps included in
requests which require authentication. This is used to enable
(unreliable) server reconfiguration over long delay network paths or
between machines whose clocks are unsynchronized. Actually the server
does not now require timestamps in authenticated requests, so this
command may be obsolete.
<p><dt><code>host <i>hostname</i></code>
<dd>Set the host to which future queries will be sent. Hostname may be
either a host name or a numeric address.

<p><dt><code>hostnames [ yes | no ]</code>
<dd>If <code>"yes"</code> is specified, host names are printed in
information displays. If <code>"no"</code> is specified, numeric
addresses are printed instead. The default is <code>"yes"</code>, unless
modified using the command line <code>-n</code> switch.

<p><dt><code>keyid <i>keyid</i></code>
<dd>This command allows the specification of a key number to be used to
authenticate configuration requests. This must correspond to a key
number the server has been configured to use for this purpose.

<p><dt><code>ntpversion 1 | 2 | 3</code>
<dd>Sets the NTP version number which <code>ntpq</code> claims in
packets. Defaults to 3, Note that mode 6 control messages (and modes,
for that matter) didn't exist in NTP version 1. There appear to be no
servers left which demand version 1.

<p><dt><code>quit</code>
<dd>Exit <code>ntpq</code>.

<p><dt><code>passwd</code>
<dd>This command prompts you to type in a password (which will not be
echoed) which will be used to authenticate configuration requests. The
password must correspond to the key configured for use by the NTP server
for this purpose if such requests are to be successful.

<p><dt><code>raw</code>
<dd>Causes all output from query commands is printed as received from
the remote server. The only formating/intepretation done on the data is
to transform nonascii data into a printable (but barely understandable)
form.

<p><dt><code>timeout <i>millseconds</i></code>
<dd>Specify a timeout period for responses to server queries. The
default is about 5000 milliseconds. Note that since <code>ntpq</code>
retries each query once after a timeout, the total waiting time for a
timeout will be twice the timeout value set.

</dl>

<p><h4>Control Message Commands</h4>

<p>Each peer known to an NTP server has a 16 bit integer association
identifier assigned to it. NTP control messages which carry peer
variables must identify the peer the values correspond to by including
its association ID. An association ID of 0 is special, and indicates the
variables are system variables, whose names are drawn from a separate
name space.

<p>Control message commands result in one or more NTP mode 6 messages
being sent to the server, and cause the data returned to be printed in
some format. Most commands currently implemented send a single message
and expect a single response. The current exceptions are the peers
command, which will send a preprogrammed series of messages to obtain
the data it needs, and the mreadlist and mreadvar commands, which will
iterate over a range of associations.

<dl>

<dt><code>associations</code>
<dd>Obtains and prints a list of association identifiers and peer
statuses for in-spec peers of the server being queried. The list is
printed in columns. The first of these is an index numbering the
associations from 1 for internal use, the second the actual association
identifier returned by the server and the third the status word for the
peer. This is followed by a number of columns containing data decoded
from the status word. Note that the data returned by the
<code>"associations"</code> command is cached internally in
<code>ntpq</code>. The index is then of use when dealing with stupid
servers which use association identifiers which are hard for humans to
type, in that for any subsequent commands which require an association
identifier as an argument, the form &amp;index may be used as an
alternative.

<p><dt><code>clockvar [ <i>assocID</i> ] [ <i>variable_name</i> [ =
<br><code>cv [ <i>assocID</i> ] [ <i>variable_name</i> [ = <i>value</i>
[ ... ]</code> ] [ ... ]</code>
<dd>Requests that a list of the server's clock variables be sent.
Servers which have a radio clock or other external synchronization will
respond positively to this. If the association identifier is omitted or
zero the request is for the variables of the <code>"system clock"</code>
and will generally get a positive response from all servers with a
clock. If the server treats clocks as pseudo-peers, and hence can
possibly have more than one clock connected at once, referencing the
appropriate peer association ID will show the variables of a particular
clock. Omitting the variable list will cause the server to return a
default variable display.

<p><dt><code>lassocations</code>
<dd>Obtains and prints a list of association identifiers and peer
statuses for all associations for which the server is maintaining state.
This command differs from the <code>"associations"</code> command only
for servers which retain state for out-of-spec client associations
(i.e., fuzzballs). Such associations are normally omitted from the
display when the <code>"associations"</code> command is used, but are
included in the output of <code>"lassociations"</code>.

<p><dt><code>lpassociations</code>
<dd>Print data for all associations, including out-of-spec client
associations, from the internally cached list of associations. This
command differs from <code>"passociations"</code> only when dealing with
fuzzballs.

<p><dt><code>lpeers</code>
<dd>Like R peers, except a summary of all associations for which the
server is maintaining state is printed. This can produce a much longer
list of peers from fuzzball servers.

<p><dt><code>mreadlist <i>assocID</i> <i>assocID</i></code>
<br><code>mrl <i>assocID</i> <i>assocID</i></code>
<dd>Like the <code>readlist</code> command, except the query is done for
each of a range of (nonzero) association IDs. This range is determined
from the association list cached by the most recent
<code>associations</code> command.

<p><dt><code>mreadvar <i>assocID</i> <i>assocID</i> [
<i>variable_name</i> [ = <i>value</i> [ ... ]</code>
<br><code>mrv <i>assocID</i> <i>assocID</i> [ <i>variable_name</i> [ =
<i>value</i> [ ... ]</code>
<dd>Like the <code>readvar</code> command, except the query is done for
each of a range of (nonzero) association IDs. This range is determined
from the association list cached by the most recent
<code>associations</code> command.

<p><dt><code>opeers</code>
<dd>An old form of the <code>peers</code> command with the reference ID
replaced by the local interface address.
<p><dt><code>passociations</code>
<dd>Prints association data concerning in-spec peers from the internally
cached list of associations. This command performs identically to the
<code>"associations"</code> except that it displays the internally
stored data rather than making a new query.

<p><dt><code>peers</code>
<dd>Obtains a list of in-spec peers of the server, along with a summary
of each peer's state. Summary information includes the address of the
remote peer, the reference ID (0.0.0.0 if the refID is unknown), the
stratum of the remote peer, the type of the peer (local, unicast,
multicast or broadcast), when the last packet was received, the polling
interval, in seconds, the reachability register, in octal, and the
current estimated delay, offset and dispersion of the peer, all in
seconds.

<p><dd>The character in the left margin indicates the fate of this peer
in the clock selection process. The codes mean: &lt;sp&gt; discarded due
to high stratum and/or failed sanity checks; <code>"x"</code> designated
falsticker by the intersection algorithm; <code>"."</code> culled from
the end of the candidate list; <code>"-"</code> discarded by the
clustering algorithmi; <code>"+"</code> included in the final selection
set; <code>"#"</code> selected for synchronizatio;n but distance exceeds
maximum; <code>"*"</code> selected for synchronization; and
<code>"o"</code> selected for synchronization, PPS signal in use.

<p><dd>Note that since the peers command depends on the ability to parse
the values in the responses it gets it may fail to work from time to
time with servers which poorly control the data formats.

<p><dd>The contents of the host field may be one of four forms. It may
be a host name, an IP address, a reference clock implementation name
with its parameter or <code>"REFCLK(&lt;implementation number&gt;,
&lt;parameter&gt;)"</code>. On <code>"hostnames no"</code> only IP-
addresses will be displayed.

<p><dt><code>pstatus <i>assocID</i></code>
<dd>Sends a read status request to the server for the given association.
The names and values of the peer variables returned will be printed.
Note that the status word from the header is displayed preceding the
variables, both in hexidecimal and in pidgeon English.

<p><dt><code>readlist [ <i>assocID</i> ]</code>
<br><code>rl [ <i>assocID</i> ]</code>
<dd>Requests that the values of the variables in the internal variable
list be returned by the server. If the association ID is omitted or is 0
the variables are assumed to be system variables. Otherwise they are
treated as peer variables. If the internal variable list is empty a
request is sent without data, which should induce the remote server to
return a default display.

<p><dt><code>readvar <i>assocID</i> <i>variable_name</i> [ =
<i>value</i> ] [ ... ]</code>
<br><code>rv <i>assocID</i> [ <i>variable_name</i> [ = <i>value</i> ] [
... ]</code>
<dd>Requests that the values of the specified variables be returned by
the server by sending a read variables request. If the association ID is
omitted or is given as zero the variables are system variables,
otherwise they are peer variables and the values returned will be those
of the corresponding peer. Omitting the variable list will send a
request with no data which should induce the server to return a default
display.

<p><dt><code>writevar <i>assocID</i> <i>variable_name</i> [ =
<i>value</i> [ ... ]</code>
<dd>Like the readvar request, except the specified variables are written
instead of read.

<p><dt><code>writelist [ <i>assocID</i> ]</code>
<dd>Like the readlist request, except the internal list variables are
written instead of read.

</dl>

<p><h4>Bugs</h4>

<p>The peers command is non-atomic and may occasionally result in
spurious error messages about invalid associations occurring and
terminating the command. The timeout time is a fixed constant, which
means you wait a long time for timeouts since it assumes sort of a worst
case. The program should improve the timeout estimate as it sends
queries to a particular host, but doesn't.

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