freebsd-nq/usr.sbin/ntp/doc/ntpq.8

.\"
.\" $FreeBSD$
.\"
.Dd January 7, 2000
.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 ...
.Sh DESCRIPTION
.Nm
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.
.Nm
can also obtain and print a list of peers in a common format by sending
multiple 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
.Dq 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
.Dq localhost
when no other host is specified.
.Nm
will prompt for commands if the standard input is a terminal device.
.Pp
.Nm
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.
.Nm
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
Command line options are described following.
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.
The following options are available:
.Bl -tag -width indent
.It Fl c Ar command
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 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
.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
.Qq > ,
followed by a file name, to the command line.
A number of interactive format commands are executed entirely within the
.Nm
program 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
.Ic ?
by itself will print a list of all the command keywords
known to this incarnation of
.Nm Ns .
A
.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.
.\"
.\" XXX Both variable_name and value below should be arguments,
.\"	not angle-quoted text.
.\"
.It Xo Ic addvars
.Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...
.Xc
.It Xo Ic rmvars
.Aq variable_name Ns
.Op ,...
.Xc
.It Ic clearvars
The data carried by NTP mode 6 messages consists of a list of items of
the form
.Xo Aq variable_name Ns
.Pf = Aq value
.Xc
where the
.Qq = Ns Aq value
is ignored, and can be omitted, in requests
to the server to read variables.
.Nm
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 clearvars
command removes all variables from the list.
.It Ic authenticate Ar yes | Ar no
Normally
.Nm
does not authenticate requests unless they are write requests.
The command
.Dq Li authenticate yes
causes
.Nm
to send authentication with all requests it makes.
Authenticated requests cause 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.
.It Ic cooked
Causes output from query commands to be
.Qq cooked Ns .
Variables
which are recognized by the server will have their values reformatted
for human consumption.
Variables which
.Nm
thinks should have a decodeable value but didn't are marked with a
trailing
.Qq ? Ns .
.It Ic debug Ar more | Ar less | Ar off
Turn 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.
The
.Ar hostname
supplied
may be either a host name or a numeric
address.
.It Ic hostnames Ar yes | Ar no
If
.Ar yes
is specified, host names are printed in information
displays.
If
.Ar no
is given, numeric addresses are printed
instead.
The default is
.Ar yes
unless modified using the command line
.Fl n
switch.
.It Ic keyid Ar 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.
.It Ic ntpversion Ar 1 | Ar 2 | Ar 3 | Ar 4
Set the NTP version number which
.Nm
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.
.It Ic quit
Exit
.Nm Ns .
.It Ic 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.
.It Ic raw
Cause all output from query commands
to be printed as received from the remote server.
The only formatting and intepretation done on the data is to
transform non-ASCII 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 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.
.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
.Ic peers
command,
which will send a preprogrammed series of messages to obtain
the data it needs, and the
.Ic mreadlist
and
.Ic 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.
Note that the data returned by the 
.Ic associations
command is cached internally in
.Nm Ns .
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
.Dq Li &index
may be used as an alternative.
.\"
.\" XXX Both variable_name and value below should be arguments,
.\"	not angle-quoted text.
.\"
.It Xo Ic clockvar
.Op Ar assocID Ns
.Pf [ Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...]
.Xc
.It Xo Ic cv
.Op Ar assocID Ns
.Pf [ Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...]
.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
.Qq 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 Ns .
.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
.Ic 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 assocID
.It Ic mrl Ar assocID 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 assocID [
.Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...]
.Xc
.It Xo Ic mrv
.Ar assocID assocID [
.Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...]
.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
Print 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 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 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.
.Pp
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 pidgeon 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 candidate
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
.Pp
The flash variable is not defined in the NTP specification,
but is included as a valuable debugging aid.
It displays the results of the packet sanity checks
defined in the NTP specification TEST1 through TEST9.
The bits for each test read in increasing sequency
from the least significant bit
and are defined as follows.
.Pp
The following TEST1 through TEST4 enumerate procedure errors.
The packet timestamps may or may not be believed,
but the remaining header data are ignored.
.Bl -tag -width indent
.It TEST1
Duplicate packet.
A copy from somewhere.
.It TEST2
Bogus packet.
It is not a reply to a message previously sent.
This can happen when the NTP daemon is restarted
and before a peer notices.
.It TEST3
Unsynchronized.
One or more timestamp fields are missing.
This normally happens when the first packet from a peer is received.
.It TEST4
Either peer delay or peer dispersion is greater than one second.
You must be joking.
.El
.Pp
The following TEST5 through TEST10
enumerate errors in the packet header.
The packet is discarded without inspecting its contents.
.Bl -tag -width indent
.It TEST5
Cryptographic authentication fails.
See the
.Qq Authentication Support
section of the
.Xr ntp.conf 5
page.
.It TEST6
Peer is unsynchronized.
Wind up its clock first.
.It TEST7
Peer stratum is greater than 15.
The peer is probably unsynchronized.
.It TEST8
Either root delay or root dispersion is greater than one second.
Too far from home.
.It TEST9
Peer cryptographic authentication fails.
Either the key identifier or key is wrong
or somebody trashed our packet.
.It TEST10
Access is denied.
See the
.Qq Access Control Support
section of the
.Xr ntp.conf 5
page.
.El
.It Ic pstatus Ar assocID
Send 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 Op Ar assocID
.It Ic rl Op 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.
.\"
.\" XXX Both variable_name and value below should be arguments,
.\"	not angle-quoted text.
.\"
.It Xo Ic readvar
.Op Ar assocID Ns
.Pf [ Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...]
.Xc
.It Xo Ic rv
.Op Ar assocID Ns
.Pf [ Aq variable_name Ns
.Op = Ns Aq value Ns
.Op ,...]
.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.
.It Xo Ic writevar
.Ar assocID
.Aq variable_name Ns
.Pf = Ns Aq value Ns
.Op ,...
.Xc
Like the
.Ic readvar
request, except the specified variables are written instead of read.
.It Ic writelist Op Ar assocID
Like the
.Ic readlist
request, except the internal list variables are written instead of read.
.El
.Sh SEE ALSO
.Xr ntp.conf 5 ,
.Xr ntpd 8 ,
.Xr ntpdc 8
.Sh HISTORY
Written by
.An Dennis Ferguson
at the University of Toronto.
.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 doesn't.