ntpq(8) — Maintenance
NAME
ntpq − Network Time Protocol (NTP) monitor program for xntpd
SYNOPSIS
/usr/bin/ntpq [-inp] [-c command] [host1 host2 ...]
FLAGS
-c commandInterprets command as an interactive format command and adds it to the list of commands to be executed on the specified host(s). Multiple -c options may be given.
-iForces ntpq to operate in interactive mode. Prompts will be written to the standard output and commands read from the standard input. This is the default.
-nOutputs all host addresses in dotted−decimal notation rather than converting to the canonical host names.
-pPrints 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 the -c or -p options sends the specified query (queries) to the indicated host(s) immediately; localhost is the default. Otherwise, ntpq attempts to read interactive format commands from the standard input.
DESCRIPTION
The ntpq program is used to monitor NTP hosts running xntpd . The program may be run either in interactive mode or controlled using command line arguments. Requests to read arbitrary variables can be assembled, with raw and formatted 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 xntpd daemons 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 first host given on the command line, 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 xntpd daemons, and therefore can be used to query any compatible daemon on the network that permits it. Note: Since NTP uses the UDP protocol, this communication will be somewhat unreliable, especially over large network topologies. Ntpq makes one attempt to retransmit requests, and will time out if the remote host is not heard from within a suitable time.
COMMANDS
Interactive Commands
Interactive format commands consist of a keyword followed by zero or more 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 daemon. These commands are as follows:
? [ 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.
timeout milliseconds
Specifies a timeout period for responses to server queries. The default is about 5000 milliseconds. Since ntpq retries each query once after a timeout, the total waiting time for a timeout will be twice the timeout value.
host [ hostname ]
Sets the host to which future queries will be sent. Hostname may be either a host name or a Internet address. If hostname is not specified, the current host is used.
hostnames yes|no
If “yes” is specified, prints host names in information displays. If “no” is given, prints Internet addresses instead. The default is “yes” unless modified using the command line -n option.
raw
Prints all output from query commands as received from the remote server. The only data formatting performed is to translate nonascii data into a printable form.
cooked
Reformats variables that are recognized by the server. Variables that ntpq doesn’t recognize are marked with a trailing “?”.
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. Ntpq maintains an internal list in which data to be included in control messages can be assembled, and sent using the readlist command 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 separated by commas 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
Adjusts level of ntpq debugging. The default is 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 status 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 is 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: The data returned by the “associations” command is cached internally in ntpq. The index is then used when dealing with servers that use association identifiers. For any subsequent commands which require an association identifier as an argument, the form &index may be used as an alternative.
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. 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
Prints data for all associations, including out−of−spec client associations, from the internally cached list of associations.
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: The status word from the header is displayed preceding the variables, both in hexadecimal and in English.
readvar [ 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.
rv [ assocID ] [ <variable_name>[=<value>][,...] ]
An easy−to−type short form for the readvar command.
writevar assocID <variable_name>=<value>[,...]
Like the readvar request, except the specified variables are written instead of read.
readlist [ assocID ]
Requests that the server return the values of the variables in the internal variable list. 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; the remote server should return a default display.
rl [ assocID ]
An easy−to−type short form of the readlist command.
mreadvar 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.
mrv assocID assocID [ <variable_name>[=<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 ] [ <variable_name>[=<value>][,...] ]
Requests that the server send a list of the clock variables. Servers that 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 “system clock” variables and will generally get a positive response from all servers with a clock. If the server treats clocks as pseudo−peers, and can possibly have more than one clock connected at once, referencing the appropriate peer association ID will show the variables of a particular clock. If you omit the variable list, the server returns a default variable display.
cv [ assocID ] [ <variable_name>[=<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 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: Since the peers command depends on the ability to parse the values in the responses it gets, it might fail to work with servers that 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.
opeers
An old form of the peers command with the reference ID replaced by the local interface address.
ERRORS
∗∗∗Can’t find host hostname
The hostname is not in the local /etc/host file.
hostname: timed out, nothing received
∗∗∗Request timed out
Check that xntpd is running on the remote host being queried.
FILES
/usr/bin/ntpq
Specifies the command path
NOTES
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 time outs since it assumes sort of a worst case.