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NTPDC(1) BSD General Commands Manual NTPDC(1)

NAME
ntpdc — vendor-specific NTPD control program

SYNOPSIS
ntpdc [-flags] [-flag [value]] [--option-name[[=| ]value]] [ host ...]

DESCRIPTION
ntpdc is deprecated. Please use ntpq(1) instead - it can do everything ntpdc used to do, and
it does so using a much more sane interface.

ntpdc is a utility program used to query ntpd(8) about its current state and to request changes
in that state. It uses NTP mode 7 control message formats described in the source code. The
program may be run either in interactive mode or controlled using command line arguments. Ex‐
tensive state and statistics information is available through the ntpdc interface. In addi‐
tion, nearly all the configuration options which can be specified at startup using ntpd's con‐
figuration file may also be specified at run time using ntpdc.

OPTIONS
-4, --ipv4
Force IPv4 DNS name resolution. This option must not appear in combination with any of
the following options: ipv6.

Force DNS resolution of following host names on the command line to the IPv4 namespace.

-6, --ipv6
Force IPv6 DNS name resolution. This option must not appear in combination with any of
the following options: ipv4.

Force DNS resolution of following host names on the command line to the IPv6 namespace.

-c cmd, --command=cmd
run a command and exit. This option may appear an unlimited number of times.

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).

-d, --debug-level
Increase debug verbosity level. This option may appear an unlimited number of times.

-D number, --set-debug-level=number
Set the debug verbosity level. This option may appear an unlimited number of times.
This option takes an integer number as its argument.

-i, --interactive
Force ntpq to operate in interactive mode. This option must not appear in combination
with any of the following options: command, listpeers, peers, showpeers.

Force ntpq to operate in interactive mode. Prompts will be written to the standard
output and commands read from the standard input.

-l, --listpeers
Print a list of the peers. This option must not appear in combination with any of the
following options: command.

Print a list of the peers known to the server as well as a summary of their state. This
is equivalent to the 'listpeers' interactive command.

-n, --numeric
numeric host addresses.

Output all host addresses in dotted-quad numeric format rather than converting to the
canonical host names.

-p, --peers
Print a list of the peers. This option must not appear in combination with any of the
following options: command.

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.

-s, --showpeers
Show a list of the peers. This option must not appear in combination with any of the
following options: command.

Print a list of the peers known to the server as well as a summary of their state. This
is equivalent to the 'dmpeers' interactive command.

-?, --help
Display usage information and exit.

-!, --more-help
Pass the extended usage information through a pager.

-> [cfgfile], --save-opts [=cfgfile]
Save the option state to cfgfile. The default is the last configuration file listed in
the OPTION PRESETS section, below. The command will exit after updating the config
file.

-< cfgfile, --load-opts=cfgfile, --no-load-opts
Load options from cfgfile. The no-load-opts form will disable the loading of earlier
config/rc/ini files. --no-load-opts is handled early, out of order.

--version [{v|c|n}]
Output version of program and exit. The default mode is `v', a simple version. The
`c' mode will print copyright information and `n' will print the full copyright notice.

OPTION PRESETS
Any option that is not marked as not presettable may be preset by loading values from configu‐
ration ("RC" or ".INI") file(s) and values from environment variables named:
NTPDC_<option-name> or NTPDC
The environmental presets take precedence (are processed later than) the configuration files.
The homerc files are "$HOME", and ".". If any of these are directories, then the file .ntprc
is searched for within those directories.

USAGE
If one or more request options are included on the command line when ntpdc 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, ntpdc 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 ntpdc utility will prompt for commands if the standard input is a terminal device.

The ntpdc utility uses NTP mode 7 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 ntpdc utility makes no attempt to retransmit requests, and will
time requests out if the remote host is not heard from within a suitable timeout time.

The operation of ntpdc are specific to the particular implementation of the ntpd(8) daemon and
can be expected to work only with this and maybe some previous versions of the daemon. Re‐
quests from a remote ntpdc utility which affect the state of the local server must be authenti‐
cated, which requires both the remote program and local server share a common key and key iden‐
tifier.

Note that in contexts where a host name is expected, a -4 qualifier preceding the host name
forces DNS resolution to the IPv4 namespace, while a -6 qualifier forces DNS resolution to the
IPv6 namespace. 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, ntpdc will attempt
to read interactive format commands from the standard input.

Interactive 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 out‐
put of a command is normally sent to the standard output, but optionally the output of individ‐
ual 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 ntpdc utility itself
and do not result in NTP mode 7 requests being sent to a server. These are described follow‐
ing.

? command_keyword

help command_keyword
A ‘?’ will print a list of all the command keywords known to this incarnation of ntpdc.
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(1) than
this manual page.

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 speci‐
fied, 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 con‐
figuration requests. This must correspond to a key number the server has been config‐
ured to use for this purpose.

quit Exit ntpdc.

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 suc‐
cessful.

timeout milliseconds
Specify a timeout period for responses to server queries. The default is about 8000
milliseconds. Note that since ntpdc retries each query once after a timeout, the total
waiting time for a timeout will be twice the timeout value set.

Control Message Commands
Query commands result in NTP mode 7 packets containing requests for information being sent to
the server. These are read-only commands in that they make no modification of the server con‐
figuration state.

listpeers
Obtains and prints a brief list of the peers for which the server is maintaining state.
These should include all configured peer associations as well as those peers whose
stratum is such that they are considered by the server to be possible future synchro‐
nization candidates.

peers Obtains a list of peers for which the server is maintaining state, along with a summary
of that state. Summary information includes the address of the remote peer, the local
interface address (0.0.0.0 if a local address has yet to be determined), the stratum of
the remote peer (a stratum of 16 indicates the remote peer is unsynchronized), the
polling interval, in seconds, the reachability register, in octal, and the current es‐
timated delay, offset and dispersion of the peer, all in seconds.

The character in the left margin indicates the mode this peer entry is operating in. A
‘+’ denotes symmetric active, a ‘-’ indicates symmetric passive, a ‘=’ means the remote
server is being polled in client mode, a ‘^’ indicates that the server is broadcasting
to this address, a ‘~’ denotes that the remote peer is sending broadcasts and a ‘~’ de‐
notes that the remote peer is sending broadcasts and a ‘*’ marks the peer the server is
currently synchronizing to.

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.

dmpeers
A slightly different peer summary list. Identical to the output of the peers command,
except for the character in the leftmost column. Characters only appear beside peers
which were included in the final stage of the clock selection algorithm. A ‘.’ indi‐
cates 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 synchro‐
nizing with.

showpeer peer_address [...]
Shows a detailed display of the current peer variables for one or more peers. Most of
these values are described in the NTP Version 2 specification.

pstats peer_address [...]
Show per-peer statistic counters associated with the specified peer(s).

clockstat clock_peer_address [...]
Obtain and print information concerning a peer clock. The values obtained provide in‐
formation on the setting of fudge factors and other clock performance information.

kerninfo
Obtain and print kernel phase-lock loop operating parameters. This information is
available only if the kernel has been specially modified for a precision timekeeping
function.

loopinfo [oneline | multiline]
Print the values of selected loop filter variables. The loop filter is the part of NTP
which deals with adjusting the local system clock. The ‘offset’ is the last offset
given to the loop filter by the packet processing code. The ‘frequency’ is the fre‐
quency error of the local clock in parts-per-million (ppm). The ‘time_const’ controls
the stiffness of the phase-lock loop and thus the speed at which it can adapt to oscil‐
lator drift. The ‘watchdog timer’ value is the number of seconds which have elapsed
since the last sample offset was given to the loop filter. The oneline and multiline
options specify the format in which this information is to be printed, with multiline
as the default.

sysinfo
Print a variety of system state variables, i.e., state related to the local server.
All except the last four lines are described in the NTP Version 3 specification,
RFC-1305.

The ‘system flags’ show various system flags, some of which can be set and cleared by
the enable and disable configuration commands, respectively. These are the auth,
bclient, monitor, pll, pps and stats flags. See the ntpd(8) documentation for the
meaning of these flags. There are two additional flags which are read only, the
kernel_pll and kernel_pps. These flags indicate the synchronization status when the
precision time kernel modifications are in use. The ‘kernel_pll’ indicates that the
local clock is being disciplined by the kernel, while the ‘kernel_pps’ indicates the
kernel discipline is provided by the PPS signal.

The ‘stability’ is the residual frequency error remaining after the system frequency
correction is applied and is intended for maintenance and debugging. In most architec‐
tures, this value will initially decrease from as high as 500 ppm to a nominal value in
the range .01 to 0.1 ppm. If it remains high for some time after starting the daemon,
something may be wrong with the local clock, or the value of the kernel variable
kern.clockrate.tick may be incorrect.

The ‘broadcastdelay’ shows the default broadcast delay, as set by the broadcastdelay
configuration command.

The ‘authdelay’ shows the default authentication delay, as set by the authdelay config‐
uration command.

sysstats
Print statistics counters maintained in the protocol module.

memstats
Print statistics counters related to memory allocation code.

iostats
Print statistics counters maintained in the input-output module.

timerstats
Print statistics counters maintained in the timer/event queue support code.

reslist
Obtain and print the server's restriction list. This list is (usually) printed in
sorted order and may help to understand how the restrictions are applied.

monlist [version]
Obtain and print traffic counts collected and maintained by the monitor facility. The
version number should not normally need to be specified.

clkbug clock_peer_address [...]
Obtain debugging information for a reference clock driver. This information is pro‐
vided only by some clock drivers and is mostly undecodable without a copy of the driver
source in hand.

Runtime Configuration Requests
All requests which cause state changes in the server are authenticated by the server using a
configured NTP key (the facility can also be disabled by the server by not configuring a key).
The key number and the corresponding key must also be made known to ntpdc. This can be done
using the keyid and passwd commands, the latter of which will prompt at the terminal for a
password to use as the encryption key. You will also be prompted automatically for both the
key number and password the first time a command which would result in an authenticated request
to the server is given. Authentication not only provides verification that the requester has
permission to make such changes, but also gives an extra degree of protection again transmis‐
sion errors.

Authenticated requests always include a timestamp in the packet data, which is included in the
computation of the authentication code. This timestamp is compared by the server to its re‐
ceive time stamp. If they differ by more than a small amount the request is rejected. This is
done for two reasons. First, it makes simple replay attacks on the server, by someone who
might be able to overhear traffic on your LAN, much more difficult. Second, it makes it more
difficult to request configuration changes to your server from topologically remote hosts.
While the reconfiguration facility will work well with a server on the local host, and may work
adequately between time-synchronized hosts on the same LAN, it will work very poorly for more
distant hosts. As such, if reasonable passwords are chosen, care is taken in the distribution
and protection of keys and appropriate source address restrictions are applied, the run time
reconfiguration facility should provide an adequate level of security.

The following commands all make authenticated requests.

addpeer peer_address [keyid] [version] [prefer]
Add a configured peer association at the given address and operating in symmetric ac‐
tive mode. Note that an existing association with the same peer may be deleted when
this command is executed, or may simply be converted to conform to the new configura‐
tion, as appropriate. If the optional keyid is a nonzero integer, all outgoing packets
to the remote server will have an authentication field attached encrypted with this
key. If the value is 0 (or not given) no authentication will be done. The version can
be 1, 2 or 3 and defaults to 3. The prefer keyword indicates a preferred peer (and
thus will be used primarily for clock synchronisation if possible). The preferred peer
also determines the validity of the PPS signal - if the preferred peer is suitable for
synchronisation so is the PPS signal.

addserver peer_address [keyid] [version] [prefer]
Identical to the addpeer command, except that the operating mode is client.

broadcast peer_address [keyid] [version] [prefer]
Identical to the addpeer command, except that the operating mode is broadcast. In this
case a valid key identifier and key are required. The peer_address parameter can be
the broadcast address of the local network or a multicast group address assigned to
NTP. If a multicast address, a multicast-capable kernel is required.

unconfig peer_address [...]
This command causes the configured bit to be removed from the specified peer(s). In
many cases this will cause the peer association to be deleted. When appropriate, how‐
ever, the association may persist in an unconfigured mode if the remote peer is willing
to continue on in this fashion.

fudge peer_address [time1] [time2] [stratum] [refid]
This command provides a way to set certain data for a reference clock. See the source
listing for further information.

auth Enables the server to synchronize with unconfigured peers only if the peer has
been correctly authenticated using either public key or private key cryptogra‐
phy. The default for this flag is enable.

bclient
Enables the server to listen for a message from a broadcast or multicast
server, as in the multicastclient command with default address. The default
for this flag is disable.

calibrate
Enables the calibrate feature for reference clocks. The default for this flag
is disable.

kernel Enables the kernel time discipline, if available. The default for this flag is
enable if support is available, otherwise disable.

monitor
Enables the monitoring facility. See the documentation here about the monlist
command or further information. The default for this flag is enable.

ntp Enables time and frequency discipline. In effect, this switch opens and closes
the feedback loop, which is useful for testing. The default for this flag is
enable.

pps Enables the pulse-per-second (PPS) signal when frequency and time is disci‐
plined by the precision time kernel modifications. See the "A Kernel Model for
Precision Timekeeping" (available as part of the HTML documentation provided in
/usr/share/doc/ntp) page for further information. The default for this flag is
disable.

stats Enables the statistics facility. See the Monitoring Options section of
ntp.conf(5) for further information. The default for this flag is disable.

restrict address mask flag [...]
This command operates in the same way as the restrict configuration file commands of
ntpd(8).

unrestrict address mask flag [...]
Unrestrict the matching entry from the restrict list.

delrestrict address mask [ntpport]
Delete the matching entry from the restrict list.

readkeys
Causes the current set of authentication keys to be purged and a new set to be obtained
by rereading the keys file (which must have been specified in the ntpd(8) configuration
file). This allows encryption keys to be changed without restarting the server.

trustedkey keyid [...]

untrustedkey keyid [...]
These commands operate in the same way as the trustedkey and untrustedkey configuration
file commands of ntpd(8).

authinfo
Returns information concerning the authentication module, including known keys and
counts of encryptions and decryptions which have been done.

traps Display the traps set in the server. See the source listing for further information.

addtrap address [port] [interface]
Set a trap for asynchronous messages. See the source listing for further information.

clrtrap address [port] [interface]
Clear a trap for asynchronous messages. See the source listing for further informa‐
tion.

reset Clear the statistics counters in various modules of the server. See the source listing
for further information.

ENVIRONMENT
See OPTION PRESETS for configuration environment variables.

FILES
See OPTION PRESETS for configuration files.

EXIT STATUS
One of the following exit values will be returned:

0 (EXIT_SUCCESS)
Successful program execution.

1 (EXIT_FAILURE)
The operation failed or the command syntax was not valid.

66 (EX_NOINPUT)
A specified configuration file could not be loaded.

70 (EX_SOFTWARE)
libopts had an internal operational error. Please report it to auto‐
gen-users AT lists.net. Thank you.