ntpq -- standard NTP query program
ntpq [-inp] [-c command] [host ...]
The ntpq utility 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 prettyprinted
output options being available. The ntpq utility 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. The ntpq utility will prompt for
commands if the standard input is a terminal device.
The ntpq utility 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. The ntpq utility makes one attempt to
retransmit requests, and will time requests out if the remote host is not
heard from within a suitable timeout time.
For examples and usage, see the "NTP Debugging Techniques" page (available
as part of the HTML documentation provided in /usr/share/doc/ntp).
The following options are available:
-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.
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.
Internal 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 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 utility itself and do not result in NTP mode 6
requests being sent to a server. These are described following.
? [command_keyword]
help [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 function and usage information about the command.
This command is probably a better source of information
about ntpq than this manual page.
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', where the `=value' is
ignored, and can be omitted, in requests to the server to read
variables. The ntpq utility 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.
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.
cooked Causes output from query commands to be "cooked", so that variables
which are recognized by ntpq will have their values reformatted
for human consumption. Variables which ntpq thinks should
have a decodable value but didn't are marked with a trailing `?'.
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 switch.
keyid 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.
ntpversion 1 | 2 | 3 | 4
Sets the NTP version number which ntpq 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.
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.
raw Causes all output from query commands is printed as received from
the remote server. The only formating/interpretation done on the
data is to transform nonascii data into a printable (but barely
understandable) 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 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. See the peers
command for a decode of the `condition' field. 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 of 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 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 pseudopeers,
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.
lassociations
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.
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.
lpeers 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.
mreadlist assocID assocID
mrl 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.
mreadvar assocID assocID [variable_name[=value ...]]
mrv 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.
opeers An old form of the peers command with the reference ID replaced
by the local interface address.
passociations
Displays 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.
peers Obtains a current list 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 this 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 milliseconds. The character in
the left margin indicates the fate of this peer in the clock
selection process. Following is a list of these characters, the
pigeon used in the rv command, and a short explanation of the
condition revealed.
space (reject) The peer is discarded as unreachable, synchronized
to this server (synch loop) or outrageous synchronization
distance.
x (falsetick) The peer is discarded by the intersection
algorithm as a falseticker.
. (excess) The peer is discarded as not among the first ten
peers sorted by synchronization distance and so is probably
a poor candidate for further consideration.
- (outlyer) The peer is discarded by the clustering algorithm
as an outlyer.
+ (candidate) The peer is a survivor and a candidate for
the combining algorithm.
# (selected) The peer is a survivor, but not among the
first six peers sorted by synchronization distance. If
the association is ephemeral, it may be demobilized to
conserve resources.
* (peer) The peer has been declared the system peer and
lends its variables to the system variables.
o ((pps.peer)) The peer has been declared the system peer
and lends its variables to the system variables. However,
the actual system synchronization is derived from a
pulse-per-second (PPS) signal, either indirectly via the
PPS reference clock driver or directly via kernel interface.
The flash variable is a valuable debugging aid. It displays the results
of the original sanity checks defined in the NTP specification RFC-1305
and additional ones added in NTP Version 4. There are eleven tests
called TEST1 through TEST11. The tests are performed in a certain order
designed to gain maximum diagnostic information while protecting against
accidental or malicious errors. The flash variable is first initialized
to zero. If after each set of tests one or more bits are set, the packet
is discarded.
Tests TEST4 and TEST5 check the access permissions and cryptographic message
digest. If any bits are set after that, the packet is discarded.
Tests TEST10 and TEST11 check the authentication state using Autokey public-key
cryptography, as described in the Authentication Options section
of ntp.conf(5). If any bits are set and the association has previously
been marked reachable, the packet is discarded; otherwise, the originate
and receive timestamps are saved, as required by the NTP protocol, and
processing continues.
Tests TEST1 through TEST3 check the packet timestamps from which the offset
and delay are calculated. If any bits are set, the packet is discarded;
otherwise, the packet header variables are saved. Tests TEST6
through TEST8 check the health of the server. If any bits are set, the
packet is discarded; otherwise, the offset and delay relative to the
server are calculated and saved. Test TEST9 checks the health of the
association itself. If any bits are set, the packet is discarded; otherwise,
the saved variables are passed to the clock filter and mitigation
algorithms.
The flash bits for each test read in increasing order from the least significant
bit are defined as follows.
TEST1 Duplicate packet. The packet is at best a casual retransmission
and at worst a malicious replay.
TEST2 Bogus packet. The packet is not a reply to a message previously
sent. This can happen when the NTP daemon is restarted and
before somebody else notices.
TEST3 Unsynchronized. One or more timestamp fields are invalid. This
normally happens when the first packet from a peer is received.
TEST4 Access is denied. See the "Access Control" page.
TEST5 Cryptographic authentication fails. See the Authentication
Options section of ntp.conf(5).
TEST6 The server is unsynchronized. Wind up its clock first.
TEST7 The server stratum is at the maximum than 15. It is probably
unsynchronized and its clock needs to be wound up.
TEST8 Either the root delay or dispersion is greater than one second,
which is highly unlikely unless the peer is synchronized to Mars.
TEST9 Either the peer delay or dispersion is greater than one second,
which is highly unlikely unless the peer is on Mars.
TEST10 The autokey protocol has detected an authentication failure. See
the Authentication Options section of ntp.conf(5).
TEST11 The autokey protocol has not verified the server or peer is
authentic and has valid public key credentials. See the
Authentication Options section of ntp.conf(5).
Additional system variables used by the NTP Version 4 Autokey support
include the following:
certificate filestamp
Shows the NTP seconds when the certificate file was created.
hostname host
Shows the name of the host as returned by the Unix gethostname(3)
library function.
flags hex
Shows the current flag bits, where the hex bits are interpreted
as follows:
0x01 autokey enabled
0x02 RSA public/private key files present
0x04 PKI certificate file present
0x08 Diffie-Hellman parameters file present
0x10 NIST leapseconds table file present
leapseconds filestamp
Shows the NTP seconds when the NIST leapseconds table file was
created.
params filestamp
Shows the NTP seconds when the Diffie-Hellman agreement parameter
file was created.
publickey filestamp
Shows the NTP seconds when the RSA public/private key files were
created.
refresh filestamp
Shows the NTP seconds when the public cryptographic values were
refreshed and signed.
tai offset
Shows the TAI-UTC offset in seconds obtained from the NIST
leapseconds table.
Additional peer variables used by the NTP Version 4 Autokey support
include the following:
certificate filestamp
Shows the NTP seconds when the certificate file was created.
flags hex
Shows the current flag bits, where the hex bits are interpreted
as in the system variable of the same name. The bits are set in
the first autokey message received from the server and then reset
as the associated data are obtained from the server and stored.
hcookie hex
Shows the host cookie used in the key agreement algorithm.
initkey key
Shows the initial key used by the key list generator in the
autokey protocol.
initsequence index
Shows the initial index used by the key list generator in the
autokey protocol.
pcookie hex
Specifies the peer cookie used in the key agreement algorithm.
timestamp time
Shows the NTP seconds when the last autokey key list was generated
and signed.
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 pidgeon
English.
readlist assocID
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] ...
Like the readvar request, except the specified variables are
written instead of read.
writelist [assocID]
Like the readlist request, except the internal list variables are
written instead of read.
ntp.conf(5), ntpd(8), ntpdc(8)
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.
FreeBSD 5.2.1 January 7, 2000 FreeBSD 5.2.1 [ Back ] |
