ntpdc(1M) System Administration Commands ntpdc(1M)NAMEntpdc - Network Time Protocol special query program
SYNOPSIS
/usr/sbin/ntpdc [-46lpsidnv?!] [-c command] [-D debuglvl] [-< optfile]
[-> optfile] [host] [...]
OPTIONS
Specifying a command line option other than -i or -n will cause the
specified query (queries) to be sent to the indicated host(s) immedi‐
ately. Otherwise, ntpdc will attempt to read interactive format com‐
mands from the standard input.
-4 Force DNS resolution of following host names on the command line
to the IPv4 namespace.
-6 Force DNS resolution of following host names on the command line
to the IPv6 namespace.
-c command
The argument command is interpreted as an interactive command
and is added to the list of commands to be executed on the spec‐
ified host(s). Multiple -c options may be given.
-i Force ntpdc to operate in interactive mode. Prompts will be
written to the standard output and commands read from the stan‐
dard input.
-l Obtain a list of peers which are known to the server(s). This
switch is equivalent to -c listpeers.
-n Output all host addresses in numeric format rather than convert‐
ing to the canonical host names.
-p Print a list of the peers known to the server as well as a sum‐
mary of their state. This is equivalent to -c peers.
-s Print a list of the peers known to the server as well as a sum‐
mary of their state, but in a slightly different format than the
-p switch. This is equivalent to -c dmpeers.
DESCRIPTIONntpdc is used to query the ntpd daemon about its current state and to
request changes in that state. The program may be run either in inter‐
active mode or controlled using command line arguments. Extensive state
and statistics information is available through the ntpdc interface. In
addition, nearly all the configuration options which can be specified
at startup using ntpd's configuration file may also be specified at run
time using ntpdc. 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.
ntpdc will prompt for commands if the standard input is a terminal
device.
ntpdc 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. ntpdc 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 daemon and can be expected to work only with this and maybe
some previous versions of the daemon. Requests from a remote ntpdc pro‐
gram which affect the state of the local server must be authenticated,
which requires both the remote program and local server share a common
key and key identifier.
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.
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 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 ntpdc program itself and do not result in NTP mode 7 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 com‐
mand. This command is probably a better source of information
about ntpq 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. Actu‐
ally 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 dis‐
plays. 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 from ntpdc to the
host(s). This must correspond to a key number which the
host/server has been configured to use for this purpose (server
options: trustedkey, and requestkey). If authentication is not
enabled on the host(s) for ntpdc commands, the command "keyid 0"
should be given; otherwise the keyid of the next subsequent
addpeer/addserver/broadcast
command will be used.
quit
exit Exit ntpdc.
debug [ no | more | less ]
With no parameter displays the current ntpdc debug level. The no
flag turns off all debugging, while more and less increase and
decrease the level respectively.
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.
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.
version
Display the version of the ntpdc command.
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 configuration 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
synchronization 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 sec‐
onds, the reachability register, in octal, and the current esti‐
mated 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 - indi‐
cates symmetric passive, a = means the remote server is being
polled in client mode, a ^ indicates that the server is broad‐
casting to this address, a ~ denotes that the remote peer is
sending broadcasts and a * marks the peer the server is cur‐
rently synchronizing to. The contents of the host field may be
one of four forms. It may be a host name, an IP address, a ref‐
erence clock implementation name with its parameter or REF‐
CLK(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 synchronizing 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 information 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 if the host supports the ntp_adj‐
time system call.
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 oscillator 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 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 synchroniza‐
tion status when the precision time kernel modifications are in
use. The kernel_pll indicates that the local clock is being dis‐
ciplined by the kernel, while the kernel_pps indicates the ker‐
nel discipline is provided by the PPS signal. The stability is
the residual frequency error remaining after the system fre‐
quency correction is applied and is intended for maintenance and
debugging. In most architectures, 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 tick may be incorrect. The broad‐
castdelay shows the default broadcast delay, as set by the
broadcastdelay configuration command. The authdelay shows the
default authentication delay, as set by the authdelay configura‐
tion command.
sysstats
Print statistics counters maintained in the protocol module.
ctlstats
Print statistics counters maintained in the control 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.
ifstats
List interface statistics for interfaces used by ntpd for net‐
work communication.
ifreload
Force rescan of current system interfaces. Outputs interface
statistics for interfaces that could possibly change. Marks
unchanged interfaces with ., added interfaces with + and deleted
interfaces with -.
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 provided 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 dis‐
abled 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 against transmission 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 receive 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 con‐
figuration 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 ade‐
quate level of security.
The following commands all make authenticated requests.
addpeer peer_address [ keyid ] [ version ]
[ minpoll# | prefer | iburst | burst | minpoll N | maxpoll N [
dynamic ] [...] ]
addpeer peer_address [ prefer | iburst | burst | minpoll N
| maxpoll N | keyid N | version N [...] ]
Add a configured peer association at the given address and oper‐
ating in symmetric active mode. Note that an existing associa‐
tion with the same peer may be deleted when this command is exe‐
cuted, or may simply be converted to conform to the new configu‐
ration, as appropriate. If the keyid is nonzero, 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. If ntpdc's key number has
not yet been set (e.g., by the keyid command), it will be set to
this value. The version# can be 1 through 4 and defaults to 3.
The remaining options are either a numeric value for minpoll# or
literals prefer, iburst, burst, minpoll N, keyid N, version N,
or maxpoll N (where N is a numeric value), and have the action
as specified in the peer configuration file command of ntpd.
See the server options page at file:///usr/share/doc/ntp/con‐
fopt.html for further information. Each flag (or its absence)
replaces the previous setting. The prefer keyword indicates a
preferred peer (and thus will be used primarily for clock syn‐
chronisation if possible). The preferred peer also determines
the validity of the PPS signal - if the preferred peer is suit‐
able for synchronisation so is the PPS signal. The dynamic key‐
word allows association configuration even when no suitable net‐
work interface is found at configuration time. The dynamic
interface update mechanism may complete the configuration when
new interfaces appear (e.g. WLAN/PPP interfaces) at a later time
and thus render the association operable.
addserver peer_address [ keyid ] [ version ] [minpoll#
| prefer | iburst | burst | minpoll N | maxpoll N [...] ]
addserver peer_address [ prefer | iburst | burst | minpoll N
| maxpoll N | keyid N | version N [...] [ dynamic ] ]
Identical to the addpeer command, except that the operating mode
is client.
addrefclock clock_address [ mode [ prefer | burst | minpoll N
| maxpoll N ...]]
Identical to the addpeer command, except that the address is a
REFCLOCK designator and it configures a hardware refclock
instead of a remote server.
broadcast peer_address [ keyid ] [ version ] [ prefer ]
Identical to the addpeer command, except that the operating mode
is broadcast. In this case a valid non-zero key identifier and
key are required. The peer_address parameter can be the broad‐
cast 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 asso‐
ciation to be deleted. When appropriate, however, the associa‐
tion 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.
enable [ auth | bclient | calibrate | kernel | monitor | ntp | pps |
stats]
disable [ auth | bclient | calibrate | kernel | monitor | ntp | pps |
stats]
These commands operate in the same way as the enable and disable
configuration file commands of ntpd. See the <a href="mis‐
copt.html">Miscellaneous Options</a> page for further informa‐
tion.
restrict address mask flag [ flag ]
This command operates in the same way as the restrict configura‐
tion file commands of ntpd.
unrestrict address mask flag [ 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 configuration file). This allows
encryption keys to be changed without restarting the server.
trustedkey keyid [...]
untrustedkey keyid [...]
controlkey keyid [...]
requestkey keyid [...]
These commands operate in the same way as the corresponding con‐
figuration file commands of ntpd.
keytype md5
This command specifies the default keytype. Since the only type
currently support is md5, this is a nop.
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 information.
reset Clear the statistics counters in various modules of the server.
See the source listing for further information.
preset [peer_address [...]]
Clear the statistics counters in various modules of the server
with respect to the indicated peers.
OPTION PRESETS
Most options may be preset by loading values from configuration 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 option-name should be in all capital let‐
ters. For example, to set the --command option, you would set the
NTPDC_COMMAND environment variable. The users home directory and the
current directory are searched for a file named .ntprc.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬──────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼──────────────────────┤
│Availability │ SUNWntp4u │
├────────────────────┼──────────────────────┤
│Interface Stability │ Uncommitted Obsolete │
└────────────────────┴──────────────────────┘
NOTES
Source for ntpdc is available in the SUNWntp4S package.
The package name that delivers this program will be changed in the next
release and should not be relied on.
SEE ALSOntpd(1M), ntpq4(1M), ntprc(4), attributes(5)ntpdc(1M)
