ntpq(1M) TCP/IP 5.4 Rel. 2.01 ntpq(1M)
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"
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interactive command.
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.
? [ commandkeyword }
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
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number the server has been configured to use for this purpose.
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 variablename[=value][,...] rmvars variablename[,...]
clearvars
The data carried by NTP mode 6 messages consists of a list of items
of the form
variablename=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
Obtains and prints a list of association identifiers and peer
statuses for all associations for which the server is maintaining
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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 ] [ variablename[=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 ] [ variablename[=value][,...] ]
An easy-to-type short form for the readvar command.
writevar assocID variablename=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 sent without data, which should induce the remote
server to return a default display.
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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 [ variablename[=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 [ variablename[=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 ] [ variablename[=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 ] [ variablename[=value][,...] ]
An easy-to-type short form of the clockvar command.
peers
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
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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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