ntp/doc/ntpq.8

.\"
.\" $FreeBSD$
.\"
.Dd May 17, 2006
.Dt NTPQ 8
.Os
.Sh NAME
.Nm ntpq
.Nd standard NTP query program
.Sh SYNOPSIS
.Nm
.Op Fl inp
.Op Fl c Ar command
.Op Ar host
.Op Ar ...
.Sh DESCRIPTION
The
.Nm
utility is used to monitor NTP daemon
.Xr ntpd 8
operations and determine performance.
It uses the standard NTP mode 6 control message formats
defined in Appendix B of the NTPv3 specification RFC1305.
The same formats are used in NTPv4, although some of the variables
have changed and new ones added.
The description on this page is for the NTPv4 variables.
.Pp
The program can 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.
The
.Nm
can also obtain and print a list of peers in a common format
by sendingmultiple queries to the server.
.Pp
If one or more request options is included on the command line
when
.Nm
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,
.Nm
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
.Nm
utility will prompt for
commands if the standard input is a terminal device.
.Pp
The
.Nm
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
.Nm
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.
.Pp
For examples and usage, see the
.Qq NTP Debugging Techniques
page
(available as part of the HTML documentation
provided in
.Pa /usr/share/doc/ntp ) .
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl 4
Force DNS resolution of following host names on the command line to the
IPv4 namespace.
.It Fl 6
Force DNS resolution of following host names on the command line to the
IPv6 namespace.
.It Fl 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
.Fl c
options may be given.
.It Fl d
Turn on debugging mode.
.It Fl i
Force
.Nm
to operate in interactive mode.
Prompts
will be written to the standard output and commands read from the
standard input.
.It Fl n
Output all host addresses in dotted-quad numeric format rather
than converting to the canonical host names.
.It Fl p
Print a list of the peers known to the server as well as a
summary of their state.
This is equivalent to the
.Ic peers
interactive command.
.El
.Pp
Note that in contexts where a host name is expected, a
.Fl 4
qualifier preceding the host name forces DNS resolution to the
IPv4 namespace, while a
.Fl 6
qualifier forces DNS resolution to the IPv6 namespace.
Specifying a
command line option other than
.Fl i
or
.Fl n
will
cause the specified query (queries) to be sent to the indicated
host(s) immediately.
Otherwise,
.Nm
will attempt to read
interactive format commands from the standard input.
.Ss "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
.Ql \&> ,
followed by a file name, to the command line.
A
number of interactive format commands are executed entirely within
the
.Nm
utility itself and do not result in NTP mode 6
requests being sent to a server.
These are described following.
.Bl -tag -width indent
.It Ic \&? Op Ar command_keyword
.It Ic help Op Ar command_keyword
A
.Sq Ic \&?
by itself will print a list of all the command
keywords known to this incarnation of
.Nm .
A
.Sq Ic \&?
followed by a command keyword will print function and usage
information about the command.
This command is probably a better
source of information about
.Nm
than this manual
page.
.It Xo Ic addvars
.Ar variable_name Ns Op = Ns Ar value ...
.Xc
.It Ic rmvars Ar variable_name ...
.It Ic clearvars
The data carried by NTP mode 6 messages consists of a list of
items of the form
.Ql variable_name=value ,
where the
.Ql =value
is ignored, and can be omitted,
in requests to the server to read variables.
The
.Nm
utility maintains an internal list in which data to be included in control
messages can be assembled, and sent using the
.Ic readlist
and
.Ic writelist
commands described below.
The
.Ic 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
.Ic rmvars
command can be used to remove individual variables from the list,
while the
.Ic clearlist
command removes all variables from the
list.
.It Ic cooked
Causes output from query commands to be "cooked", so that
variables which are recognized by
.Nm
will have their
values reformatted for human consumption.
Variables which
.Nm
thinks should have a decodable value but did not are
marked with a trailing
.Ql \&? .
.It Xo Ic debug
.Cm more |
.Cm less |
.Cm off
.Xc
Turns internal query program debugging on and off.
.It Ic delay Ar 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.
.It Ic host Ar hostname
Set the host to which future queries will be sent.
Hostname may
be either a host name or a numeric address.
.It Ic hostnames Cm yes | Cm no
If
.Cm yes
is specified, host names are printed in
information displays.
If
.Cm no
is specified, numeric
addresses are printed instead.
The default is
.Cm yes ,
unless
modified using the command line
.Fl n
switch.
.It Ic keyid Ar keyid
This command specifies the 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.
.It Xo Ic ntpversion
.Cm 1 |
.Cm 2 |
.Cm 3 |
.Cm 4
.Xc
Sets the NTP version number which
.Nm
claims in
packets.
Defaults to 3, Note that mode 6 control messages (and
modes, for that matter) did not exist in NTP version 1.
There appear
to be no servers left which demand version 1.
.It Ic passwd
This command prompts for a password (which will not be echoed) which will
be used to authenticate configuration requests.
The password must
correspond to the key configured for NTP server for this purpose.
.It Ic quit
Exit
.Nm .
.It Ic raw
Causes all output from query commands is printed as received
from the remote server.
The only formatting/interpretation done on
the data is to transform nonascii data into a printable (but barely
understandable) form.
.It Ic timeout Ar milliseconds
Specify a timeout period for responses to server queries.
The
default is about 5000 milliseconds.
Note that since
.Nm
retries each query once after a timeout, the total waiting time for
a timeout will be twice the timeout value set.
.El
.Ss Control Message Commands
Each association known to an NTP server has a 16 bit integer association
identifier.
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.
.Pp
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.
.Bl -tag -width indent
.It Ic 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
.Sq condition
field.
Note that the data
returned by the
.Ic associations
command is cached internally
in
.Nm .
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.
.It Xo Ic clockvar Op Ar assocID
.Oo
.Ar variable_name Ns Op = Ns Ar value ...
.Oc
.Ar ...
.Xc
.It Xo Ic cv Op Ar assocID
.Oo
.Ar variable_name Ns Op = Ns Ar value ...
.Oc
.Ar ...
.Xc
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
.Sq 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.
.It Ic 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
.Ic 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
.Ic associations
command is
used, but are included in the output of
.Ic lassociations .
.It Ic lpassociations
Print data for all associations, including out-of-spec client
associations, from the internally cached list of associations.
This
command differs from
.Ic passociations
only when dealing with
fuzzballs.
.It Ic 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.
.It Ic mreadlist Ar assocID Ar assocID
.It Ic mrl Ar assocID Ar assocID
Like the
.Ic 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
.Ic associations
command.
.It Xo Ic mreadvar Ar assocID Ar assocID
.Oo
.Ar variable_name Ns Op = Ns Ar value ...
.Oc
.Xc
.It Xo Ic mrv Ar assocID Ar assocID
.Oo
.Ar variable_name Ns Op = Ns Ar value ...
.Oc
.Xc
Like the
.Ic 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
.Ic associations
command.
.It Ic opeers
An old form of the
.Ic peers
command with the reference ID
replaced by the local interface address.
.It Ic passociations
Displays association data concerning in-spec peers from the
internally cached list of associations.
This command performs
identically to the
.Ic associations
except that it displays
the internally stored data rather than making a new query.
.It Ic 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 at the left margin of each line shows the
synchronization status of the association and is a valuable
diagnostic tool.
The encoding and meaning of this character,
called the tally code, is given later in this page.
.It Ic pstatus Ar 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.
.It Ic readlist Ar assocID
.It Ic rl Ar 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.
.It Xo Ic readvar Ar assocID
.Ar variable_name Ns Op = Ns Ar value
.Ar ...
.Xc
.It Xo Ic rv Ar assocID
.Ar variable_name Ns Op = Ns Ar value
.Ar ...
.Xc
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.
The
encoding and meaning of the variables derived from NTPv3 is given in
RFC-1305; the encoding and meaning of the additional NTPv4 variables are
given later in this page.
.It Xo Ic writevar Ar assocID
.Ar variable_name Ns Op = Ns Ar value
.Ar ...
.Xc
Like the readvar request, except the specified variables are
written instead of read.
.It Ic writelist Op Ar assocID
Like the readlist request, except the internal list variables
are written instead of read.
.El
.Ss Tally Codes
The character in the left margin in the
.Sq peers
billboard,
called the tally code, shows the fate of each association
in the clock selection process.
Following is a list of these characters, the pigeon used
in the
.Ic rv
command, and a short explanation of the condition revealed.
.Bl -tag -width indent
.It space
.Pq reject
The peer is discarded as unreachable, synchronized to this server (synch
loop) or outrageous synchronization distance.
.It x
.Pq falsetick
The peer is discarded by the intersection algorithm as a falseticker.
.It \&.
.Pq 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.
.It \&-
.Pq outlyer
The peer is discarded by the clustering algorithm as an outlyer.
.It \&+
.Pq candidat
The peer is a survivor and a candidate for the combining algorithm.
.It \&#
.Pq 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.
.It \&*
.Pq sys.peer
The peer has been declared the system peer and lends its variables to the
system variables.
.It o
.Pq 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.
.El
.Ss System Variables
The
.Cm status ,
.Cm leap ,
.Cm stratum ,
.Cm precision ,
.Cm rootdelay ,
.Cm rootdispersion ,
.Cm refid ,
.Cm reftime ,
.Cm poll ,
.Cm offset ,
and
.Cm frequency
variables are described in RFC-1305
specification.
Additional NTPv4 system variables include the following.
.Bl -tag -width indent
.It version
Everything you might need to know about the software version and generation
time.
.It processor
The processor and kernel identification string.
.It system
The operating system version and release identifier.
.It state
The state of the clock discipline state machine.
The values are described
in the architecture briefing on the NTP Project page linked from
www.ntp.org.
.It peer
The internal integer used to identify the association currently designated
the system peer.
.It jitter
The estimated time error of the system clock measured as an exponential
average of RMS time differences.
.It stability
The estimated frequency stability of the system clock measured as an
exponential average of RMS frequency differences.
.El
.Pp
When the NTPv4 daemon is compiled with the OpenSSL software library, additional
system variables are displayed, including some or all of the following,
depending on the particular dance:
.Bl -tag -width indent
.It flags
The current flags word bits and message digest algorithm identifier (NID)
in hex format.
The high order 16 bits of the four-byte word contain the NID
from the OpenSSL ligrary, while the low-order bits are interpreted as
follows:
.Bl -tag -width indent
.It 0x01
autokey enabled
.It 0x02
NIST leapseconds file loaded
.It 0x10
PC identity scheme
.It 0x20
IFF identity scheme
.It 0x40
GQ identity scheme
.El
.It hostname
The name of the host as returned by the Unix
.Fn gethostname
library
function.
.It hostkey
The NTP filestamp of the host key file.
.It cert
A list of certificates held by the host.
Each entry includes the subject,
issuer, flags and NTP filestamp in order.
The bits are interpreted as
follows:
.Bl -tag -width indent
.It 0x01
certificate has been signed by the server
.It 0x02
certificate is trusted
.It 0x04
certificate is private
.It 0x08
certificate contains errors and should not be trusted
.El
.It leapseconds
The NTP filestamp of the NIST leapseconds file.
.It refresh
The NTP timestamp when the host public cryptographic values were refreshed
and signed.
.It signature
The host digest/signature scheme name from the OpenSSL library.
.It tai
The TAI-UTC offset in seconds obtained from the NIST leapseconds table.
.El
.Ss Peer Variables
The
.Cm status ,
.Cm srcadr ,
.Cm srcport ,
.Cm dstadr ,
.Cm dstport ,
.Cm leap ,
.Cm stratum ,
.Cm precision ,
.Cm rootdelay ,
.Cm rootdispersion ,
.Cm readh ,
.Cm hmode ,
.Cm pmode ,
.Cm hpoll ,
.Cm ppoll ,
.Cm offset ,
.Cm delay ,
.Cm dspersion ,
.Cm reftime
variables are described in the RFC-1305 specification, as
are the timestamps
.Cm org ,
.Cm rec
and
.Cm xmt .
Additional NTPv4 system variables include
the following.
.Bl -tag -width indent
.It flash
The flash code for the most recent packet received.
The encoding and
meaning of these codes is given later in this page.
.It jitter
The estimated time error of the peer clock measured as an exponential
average of RMS time differences.
.It unreach
The value of the counter which records the number of poll intervals since
the last valid packet was received.
.El
.Pp
When the NTPv4 daemon is compiled with the OpenSSL software library, additional
peer variables are displayed, including the following:
.Bl -tag -width indent
.It flags
The current flag bits.
This word is the server host status word with
additional bits used by the Autokey state machine.
See the source code for
the bit encoding.
.It hostname
The server host name.
.It initkey Ar key
The initial key used by the key list generator in the Autokey protocol.
.It initsequence Ar index
The initial index used by the key list generator in the Autokey protocol.
.It signature
The server message digest/signature scheme name from the OpenSSL software
library.
.It timestamp Ar time
The NTP timestamp when the last Autokey key list was generated and signed.
.El
.Ss Flash Codes
The
.Cm flash
code is a valuable debugging aid displayed in the peer variables
list.
It shows the results of the original sanity checks defined in the NTP
specification RFC-1305 and additional ones added in NTPv4.
There are 12 tests
designated
.Sy TEST1
through
.Sy TEST12 .
The tests are performed in a certain order
designed to gain maximum diagnostic information while protecting against
accidental or malicious errors.
The
.Sy flash
variable is initialized to zero as
each packet is received.
If after each set of tests one or more bits are set,
the packet is discarded.
.Pp
Tests
.Sy TEST1
through
.Sy 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.
.Sy TEST4
and
.Sy TEST5
are associated with
access control and cryptographic authentication.
If any bits are set, the
packet is discarded immediately with nothing changed.
.Pp
Tests
.Sy TEST6
through
.Sy 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.
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.
.Pp
Tests
.Sy TEST10
through
.Sy TEST12
check the authentication state using Autokey
public-key cryptography, as described in the
.Sx Authentication Options
section of
.Xr 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.
.Pp
The
.Cm flash
bits for each test are defined as follows.
.Bl -tag -width indent
.It 0x001
.Pq TEST1
Duplicate packet.
The packet is at best a casual retransmission and at
worst a malicious replay.
.It 0x002
.Pq 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.
.It 0x004
.Pq TEST3
Unsynchronized.
One or more timestamp fields are invalid.
This normally
happens when the first packet from a peer is received.
.It 0x008
.Pq TEST4
Access is denied.
See the
.Sx Access Control Support
section of
.Xr ntp.conf 5 .
.It 0x010
.Pq TEST5
Cryptographic authentication fails.
See the
.Sx Authentication Options
section of
.Xr ntp.conf 5 .
.It 0x020
.Pq TEST6
The server is unsynchronized.
Wind up its clock first.
.It 0x040
.Pq TEST7
The server stratum is at the maximum than 15.
It is probably unsynchronized
and its clock needs to be wound up.
.It 0x080
.Pq TEST8
Either the root delay or dispersion is greater than one second, which is
highly unlikely unless the peer is unsynchronized to Mars.
.It 0x100
.Pq TEST9
Either the peer delay or dispersion is greater than one second, which is
higly unlikely unless the peer is on Mars.
.It 0x200
.Pq TEST10
The autokey protocol has detected an authentication failure.
See the
.Sx Authentication Options
section of
.Xr ntp.conf 5 .
.It 0x400
.Pq TEST11
The autokey protocol has not verified the server or peer is proventic and
has valid public key credentials.
See the
.Sx Authentication Options
section of
.Xr ntp.conf 5 .
.It 0x800
.Pq TEST12
A protocol or configuration error has occurred in the public key algorithms
or a possible intrusion event has been detected.
See the
.Sx Authentication Options
section of
.Xr ntp.conf 5 .
.El
.Sh SEE ALSO
.Xr ntp.conf 5 ,
.Xr ntpd 8 ,
.Xr ntpdc 8
.Sh BUGS
The
.Ic 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 does not.