NTPQ(8) UNIX System V(LOCAL) NTPQ(8)
NAME
ntpq | standard Network Time Protocol query program
SYNOPSIS
ntpq [ |inp ] [ |c command ] [ host ] [ ... ]
DESCRIPTION
Ntpq 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. Ntpq can also obtain and print a list of peers
in a common format by sending multiple queries to the server.
If one or more request options is included on the command line when ntpq
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, ntpq 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. Ntpq will prompt for commands
if the standard input is a terminal device.
Ntpq 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. Ntpq makes one attempt to retransmit requests, and
will time requests out if the remote host is not heard from within a
suitable time out time.
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, ntpq will attempt
to read interactive format commands from the standard input.
|c 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.
|i Force ntpq to operate in interactive mode. Prompts will be
written to the standard output and commands read from the
standard input.
|n Output all host addresses in dotted-quad numeric format rather
than converting to the canonical host names.
|p Print a list of the peers known to the server as well as a
summary of their state. This is equivalent to the "peers"
interactive command.
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INTERNAL COMMANDS
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 ">", followed by a file
name, to the command line.
A number of interactive format commands are executed entirely within the
ntpq program itself and do not result in NTP mode 6 requests being sent
to a server. These are described following.
? [ command_keyword }
A "?" by itself will print a list of all the command keywords known to
this incarnation of ntpq. A "?" followed by a command keyword will print
funcation and usage information about the command. This command is
probably a better source of information about ntpq than this manual page.
timeout millseconds
Specify a time out period for responses to server queries. The default
is about 5000 milliseconds. Note that since ntpq retries each query once
after a time out the total waiting time for a time out will be twice the
time out value set.
delay milliseconds
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 time
stamps in authenticated requests, so this command may be obsolete.
host hostname
Set the host to which future queries will be sent. Hostname may be
either a host name or a numeric address.
poll [ # ] [ verbose ]
Poll the current server in client mode. The first argument is the number
of times to poll (default is 1) while the second argument may be given to
obtain a more detailed output of the results. This command is currently
just wishful thinking.
keyid #
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.
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passwd
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.
hostnames yes|no
If "yes" is specified, host names are printed in information displays.
If "no" is given, numeric addresses are printed instead. The default is
"yes" unless modified using the command line |n switch.
raw
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.
cooked
Causes output from query commands to be "cooked". Variables which are
recognized by the server will have their values reformatted for human
consumption. Variables which ntpq thinks should have a decodeable value
but didn't are marked with a trailing "?".
ntpversion 1|2
Sets the NTP version number which ntpq claims in packets. Defaults to 2
since 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.
authenticate yes|no
Normally ntpq does not authenticate requests unless they are write
requests. The command authenticate yes causes ntpq 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.
addvars <variable_name>[=<value>][,...] rmvars <variable_name>[,...]
clearvars
The data carried by NTP mode 6 messages consists of a list of items of
the form
<variable_name>=<value>
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where the "=<value>" is ignored, and can be omitted, in requests to the
server to read variables. Ntpq 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.
debug more|less|off
Turns internal query program debugging on and off.
quit
Exit ntpq.
CONTROL MESSAGE COMMANDS
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.
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.
associations
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 "associations" command is
cached internally in ntpq. 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 &index may be used as an
alternative.
lassocations
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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 "associations" 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
"associations" command is used, but are included in the output of
"lassociations".
passociations
Prints association data concerning in-spec peers from the internally
cached list of associations. This command performs identically to the
"associations" except that it displays the internally stored data rather
than making a new query.
lpassociations
Print data for all associations, including out-of-spec client
associations, from the internally cached list of associations. This
command differs from "passociations" only when dealing with fuzzballs.
pstatus assocID
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.
readvar [ assocID ] [ <variable_name>[=<value>][,...] ]
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.
rv [ assocID ] [ <variable_name>[=<value>][,...] ]
An easy-to-type short form for the readvar command.
writevar assocID <variable_name>=<value>[,...]
Like the readvar request, except the specified variables are written
instead of read.
readlist [ assocID ]
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
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sent without data, which should induce the remote server to return a
default display.
rl [ assocID ]
An easy-to-type short form of the readlist command.
writelist [ assocID ]
Like the readlist request, except the internal list variables are written
instead of read.
mreadvar assocID assocID [ <variable_name>[=<value>][,...] ]
Like the readvar 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 associations command.
mrv assocID assocID [ <variable_name>[=<value>][,...] ]
An easy-to-type short form of the mreadvar command.
mreadlist assocID assocID
Like the readlist 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 associations command.
mrl assocID assocID
An easy-to-type short form of the mreadlist command.
clockvar [ assocID ] [ <variable_name>[=<value>][,...] ]
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 "system clock" 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.
cv [ assocID ] [ <variable_name>[=<value>][,...] ]
An easy-to-type short form of the clockvar command.
peers
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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 polling interval, in seconds, the
reachability register, in octal, and the current estimated delay, offset
and dispersion of the peer, all in seconds. In addition, the character
in the left margin indicates the fate of this peer in the clock selection
algorithm. Characters only appear beside peers which were included in
the final stage of the clock selection algorithm. A "." indicates that
this peer was cast off in the falseticker detection, while a "+"
indicates that the peer made it through. A "*" denotes the peer the
server is currently synchronizing with. 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.
lpeers
Like 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.
opeers
An old form of the "peers" command with the reference ID replaced by the
local interface address.
HISTORY
Written by Dennis Ferguson at the University of Toronto.
BUGS
The peers command is non-atomic and may occasionally result in spurious
error messages about invalid associations occuring and terminating the
command.
The timeout time is a fixed constant, which means you wait a long time
for time outs since it assumes sort of a worst case. The program should
improve the time out estimate as it sends queries to a particular host,
but doesn't.
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