ntpq(1M) ntpq(1M)
NAME [Toc] [Back]
ntpq - standard Network Time Protocol query program
SYNOPSIS [Toc] [Back]
ntpq [ -dinp ] [ -c command ] [ host ] [ ... ]
DESCRIPTION [Toc] [Back]
ntpq is used to query NTP servers, that 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 mode using command line arguments. Requests to read
and write arbitrary variables can be assembled, with raw and
pretty-printed output options 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 to
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 compatible 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 out if the remote host is not heard from within a
suitable timeout time.
COMMAND LINE OPTIONS [Toc] [Back]
The command line options supported are described below. 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 command
Interactive format command. The command is added to the list of
commands to be executed on the specified host(s). Multiple -c
options may be given.
-d Print debugging information.
-i Force ntpq to operate in interactive mode. Prompts will be
written to the standard output and commands read from the
standard input.
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-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.
INTERACTIVE COMMANDS [Toc] [Back]
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 needs to 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, on 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 below.
? [command_keyword]
help [command_keyword]
A ? or help by itself will print a list of all the command
keywords known to this version of ntpq. A ? or help
followed by a command keyword will print function and usage
information about the command.
addvars [variable_name=value][ ... ]
rmvars [variable_name=value][ ... ]
clearvars The data carried by NTP mode 6 messages consists of a list
of items of the form variable_name = value, 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.
addvars This 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.
rmvars This command can be used to remove individual variables from
the list.
clearlist This command removes all variables from the list.
authenticate [yes|no]
Normally ntpq does not authenticate requests unless they are
write requests. The command authenticate yes causes ntpq to
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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.
cooked Causes output from query commands to be cooked. Variables
which are recognized by the server will have their values
reformatted for human usage.
debug [more|less|off]
Turns internal query program debugging on and off.
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
timestamps 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.
hostnames [yes|no]
If yes is specified, host names are printed in information
displays. If no is specified, numeric addresses are printed
instead. The default is yes, unless modified using the
command line -n option.
keyid keyid-id
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.
ntpversion [1|2|3]
Sets the NTP version number which ntpq claims in packets.
Defaults to 3, Note that mode 6 control messages (and
modes) did not exist in NTP version 1. There appears to be
no servers left which demand version 1.
quit Exit ntpq.
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.
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raw Causes all output from query commands to be printed as
received from the remote server. The only
formatting/interpretation done on the data is to transform
nonascii data into a printable form.
timeout milliseconds
Specify a timeout period for responses to server queries.
The default is about 5000 milliseconds. Note that since ntpq
retries each query once after a timeout, the total waiting
time for a timeout will be twice the timeout value set.
CONTROL MESSAGE COMMANDS [Toc] [Back]
Each peer known to an NTP server has 16 bit integer association
identifier assigned to it. NTP control messages which carry peer
variables must identify the peer, the values it corresponds 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. The supported control messages
are listed below:
associations
Obtains and prints a list of association identifiers and peer
status for in-spec peers of the server being queried. The list
is printed in columns. The first of these columns is an index
numbering the associations from 1 for internal use, the second
column is the actual association identifier returned by the
server and the third column is 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 and index may
be used as an alternative.
clockvar [assocID][variable_name[=value[ ... ]][ ... ]]
cv [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
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the variables of the system clock and will generally get a
positive response from all servers with a clock. If the server
treats the clocks as pseudo-peers, then 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.
lassociations
Obtains and prints a list of association identifiers and peer
status 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.
lpassociations
Print data for all associations, including out-of-spec client
associations, from the internally cached list of associations.
This command differs from passociations command only when
dealing with fuzzballs.
lpeers Similar to peers command, 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.
mreadlist assocID assocID
mrl assocID assocID
Similar to the readlist command, except the query is done for
each range of (nonzero) association IDs. This range is
determined from the association list cached by the most recent
associations command.
mreadvar assocID assocID [variable_name[=value][ ... ]]
mrv assocID assocID [variable_name[=value][ ... ]]
Similar to the readvar command, except the query is done for
each range of (nonzero) association IDs. This range is
determined from the association list cached by the most recent
associations command.
opeers An old form of the peers command with the reference ID
replaced by the local interface address.
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
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internally stored data rather than making a new query.
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 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.
The character in the left margin indicates the fate of this
peer in the clock selection process. The codes mean:
<BLANK> discarded due to high stratum and/or failed sanity
checks;
x designated falseticker by the intersection
algorithm;
. culled from the end of the candidate list;
- discarded by the clustering algorithm;
+ included in the final selection set;
# selected for synchronization but distance exceeds
maximum;
* selected for synchronization; and
o selected for synchronization, PPS signal in use.
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. 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
REFCLK( <implementation number>, <parameter>). On hostnames no only
IP-addresses will be displayed.
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 hexadecimal and in
English.
readlist [assocID]
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rl [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.
readvar assocID variable_name [=value][ ... ]]
rv 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.
writevar assocID variable_name [=value][ ... ]]
Similar to the readvar command, except the specified variables
are written instead of read.
writelist [assocID]
Similar to the readlist command, except the internal list
variables are written instead of read.
WARNINGS [Toc] [Back]
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 a long wait for timeouts since it assumes a worst case.
FILES [Toc] [Back]
/etc/ntp.keys Contains the encryption keys used for
authentication.
AUTHOR [Toc] [Back]
ntpq was developed by Dennis Ferguson at the University of Toronto.
SEE ALSO [Toc] [Back]
ntpdate(1M), xntpd(1M), xntpdc(1M).
DARPA Internet Request For Comments RFC1035 Assigned Numbers.
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