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Commands Reference, Volume 6
Starts the query/control program
for the Network Time Protocol daemon, xntpd. This command
only applies to AIX 4.2 or later.
xntpdc [ -i ]
[ -l ] [ -n ] [ -p ] [ -s ] [ -c SubCommand ]
[ Host ... ]
The xntpdc command
queries the xntpd daemon about its current state and requests
changes to that state. It runs either in interactive mode or by using
command-line arguments. The xntpdc command interface
displays extensive state and statistics information. In addition,
nearly all the configuration options which you can specify at start-up using
the xntpd daemon's configuration file, you can also specify at
run-time using the xntpdc command.
If you enter the
xntpdc command with one or more request flags, the NTP servers
running on each of the hosts specified (or defaults to local host) receive
each request. If you do not enter any request flags, the
xntpdc command tries to read commands from standard input and run
them on the NTP server running on the first host specified or on the local
host by default. It prompts for subcommands if standard input is the
terminal.
The xntpdc command
uses NTP mode 7 packets to communicate with the NTP server and can query any
compatible server on the network which permits it.
The xntpdc command
makes no attempt to retransmit requests, and will time-out requests if the
remote host does not respond within a suitable time.
Specifying a flag other than
-i or -n sends the queries to the specified hosts
immediately. Otherwise, the xntpdc command attempts to read
interactive format commands from standard input.
| -c SubCommand
| Specifies an interactive format command. This flag adds
SubCommand to the list of commands to run on the specified
hosts. You can enter multiple -c flags.
|
| -i
| Specifies interactive mode. Standard output displays prompt and
standard input reads commands.
|
| -l
| (lowercase L) Displays a list of the peers known to the servers.
This is the same as the listpeers subcommand.
|
| -n
| Displays all host addresses in dotted decimal format
(0.0.0.0) rather than the canonical host names.
|
| -p
| Displays a list of the peers known to the server and a summary of their
state. This is the same as the peers subcommand.
|
| -s
| Displays a list of the peers known to the server and a summary of their
state but in a format different from the -p flag. This is
the same as the dmpeers subcommand.
|
| Host ...
| Specifies the hosts.
|
This command returns the
following exit values:
| 0
| Successful completion.
|
| >0
| An error occurred.
|
Access Control: You must be
part of the system group to run this command.
Auditing Events: N/A
Displays per-peer statistic
counters associated with the specified peers.
- To start the
query/control program for the Network Time Protocol daemon, enter:
xntpdc
- To display the
statistic counters of the peer at address 127.127.1.0 on
host 9.3.149.107, enter:
xntpdc -c "pstats 127.127.1.0" 9.3.149.107
Output similar to the following appears:
remote host: LOCAL(0)
local interface: 127.0.0.1
time last received: 49s
time until next send: 15s
reachability change: 818s
packets sent: 13
packets received: 13
bad authentication: 0
bogus origin: 0
duplicate: 0
bad dispersion: 4
bad reference time: 0
candidate order: 1
You can run a number of
interactive format subcommands entirely within the xntpdc command
that do not send NTP mode 7 requests to a server. The following
subcommands can only be used while running the xntpdc query
program.
Interactive format subcommands
consist of a keyword followed by zero to four arguments. You only need
to type enough characters of the full keyword to uniquely identify the
subcommand. The output of a subcommand goes to standard output, but you
can redirect the output of individual subcommands to a file by appending a
greater-than sign (>), followed by a file name, to the command
line.
| ? [ SubCommand ]
| Displays command usage information. When used without
SubCommand, displays a list of all the xntpdc command
keywords. When used with SubCommand, displays function and
usage information about the command.
|
| help [ SubCommand ]
| Same as the ? [ Subcommand ]
subcommand.
|
| delay
Milliseconds
| Specifies the time interval to add to timestamps included in requests
which require authentication. This subcommand enables unreliable server
reconfiguration over long delay network paths or between machines whose clocks
are unsynchronized. If you enter this subcommand without an argument,
it prints the current setting for this subcommand.
|
| host HostName
| Specifies the host to send queries to. HostName may be
either a host name or a numeric address. If you enter this subcommand
without an argument, it prints the current setting for this subcommand.
|
| hostnames
yes | no
| Specifies whether to display the host name (yes) or the
numeric address (no). The default is yes unless
the -n flag is used. If you enter this subcommand without an
argument, it prints the current setting for this subcommand.
|
| keyid
Number
| Specifies the server key number to use to authenticate configuration
requests. If you enter this subcommand without an argument, it prints
the current setting for this subcommand.
|
| passwd
| Prompts you to type in the NTP server authentication password to use to
authenticate configuration requests.
|
| quit
| Exits the xntpdc query program.
|
| timeout
Milliseconds
| Specifies the time-out period for responses to server queries. The
default is 8000 milliseconds. If you enter this subcommand without an
argument, it prints the current setting for this subcommand.
|
The xntpdc query
subcommands result in sending NTP mode 7 packets containing requests to the
server. These subcommands are read-only (they do not modify the server
configuration state).
| clkbug
ClockPeerAddress [ Addr2 ] [ Addr3 ] [
Addr4 ]
|
|
| Displays debugging information for a reference clock driver. Some
clock drivers provide this information which is mostly undecodable without a
copy of the driver source in hand.
|
| clockbug
ClockPeerAddress [ Addr2 ] [ Addr3 ] [
Addr4 ]
|
|
| Displays information concerning a peer clock. The values obtained
provide information on the setting of fudge factors and other clock
performance information.
|
| dmpeers
| Displays a list of peers for which the server is maintaining state, along
with a summary of that state. Identical to the output of the
peers subcommand 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.
The possible character in the
leftmost column are:
- .
- Indicates that this peer was cast off in the falseticker detection.
- +
- Indicates that the peer made it through.
- *
- Denotes the peer the server is currently synchronizing with.
|
| iostats
| Displays statistics counters maintained in the input-output
module.
|
| kerninfo
| Displays kernel phase-lock loop operating parameters. This
information is available only if the kernel of the hosts being generated has
been specially modified for a precision timekeeping function.
|
| listpeers
| Displays a brief list of the peers for which the server is maintaining
state. These include all configured peer associations as well as those
peers whose stratum is such that the server considers them to be possible
future synchronization candidates.
|
| loopinfo [
oneline | multiline ]
| Displays the values of selected loop filter variables. The loop
filter is the part of NTP that adjusts the local system clock. The
offset is the last offset given to the loop filter by the packet
processing code. The frequency is the frequency error of the
local clock in parts-per-million (ppm). The poll adjust
controls the stiffness (resistance to change) of the phase-lock loop and the
speed at which it can adapt to oscillator drift. The watchdog
timer is the number of elapsed seconds since the last sample offset
given to the loop filter. The oneline and
multiline options specify the format to display this
information. The multiline option is the default.
|
| memstats
| Displays statistics counters related to memory allocation code.
|
| monlist
| Displays traffic counts collected and maintained by the monitor
facility.
|
| peers
| Displays a list of peers for which the server is maintaining state, along
with a summary of that state. Summary information includes:
- address of the remote peer,
- reference ID (0.0.0.0 for an
unknown reference ID),
- the stratum of the remote peer (a stratum of 16
indicates the remote peer is unsynchronized),
- the polling interval (seconds),
- the reachability register (octal), and
- the current estimated delay, offset and dispersion of
the peer (seconds).
The character in the left margin
indicates the mode this peer entry is in:
- +
- symmetric active.
- -
- symmetric passive.
- =
- remote server polled in client mode.
- ^
- server is broadcasting to this address.
- ~
- remote peer is sending broadcasts.
- *
- marks the peer the server is currently synchronizing to.
The contents of the host field
may be a host name, an IP address, a reference clock implementation name with
its parameter or REFCLK (ImplementationNumber,
Parameter). Only IP addresses display when using
hostnames no.
|
| pstats
PeerAddress [ Addr2 ] [ Addr3 ] [ Addr4
]
|
|
| Displays per-peer statistic counters associated with the specified
peers.
|
| reslist
| Displays the server's restriction list which may help to understand
how the restrictions are applied.
|
| sysinfo
| Displays a variety of system state variables 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 statements. The stability
is the residual frequency error remaining after applying the system frequency
correction. You use it 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 broadcastdelay shows the default broadcast
delay, as set by the broadcastdelay configuration statement, while
the authdelay shows the default authentication delay, as set by the
authdelay configuration statement.
|
| sysstats
| Displays statistics counters maintained in the protocol module.
|
| timerstats
| Displays statistics counters maintained in the timer/event queue support
code.
|
The server authenticates all
requests which cause state changes in the server by using a configured NTP
key. The server can also disable this facility by not configuring a
key. You must make the key number and the corresponding key known to
the xtnpdc command. You can do this by using the
keyid and passwd subcommands, which prompts at the
terminal for a password to use as the encryption key. The
xtnpdc command will also prompt you automatically for both the key
number and password the first time you give a subcommand which would result in
an authenticated request to the server. Authentication not only
verifies that the requester has permission to make such changes, but also
protects against transmission errors.
Authenticated requests always
include a timestamp in the packet data, as does the computation of the
authentication code. The server compares this timestamp to the time at
which it receives the packet.
The server rejects the request if
they differ by more than 10 seconds. This makes simple replay attacks
on the server, by someone able to overhear traffic on your LAN, much more
difficult. It also makes it more difficult to request configuration
changes to your server from topologically remote hosts. While the
reconfiguration facility works well with a server on the local host, and may
work adequately between time-synchronized hosts on the same LAN, it works very
poorly for more distant hosts. So, if you choose reasonable passwords,
take care in the distribution and protection of keys and apply appropriate
source address restrictions, the run-time reconfiguration facility should
provide an adequate level of security.
The following subcommands all
make authenticated requests.
| addpeer
PeerAddress [ Keyid ] [ Version ] [
prefer ]
|
|
| Adds a configured peer association operating in symmetric active mode at
the specified address. You may delete an existing association with the
same peer or simply convert an existing association to conform to the new
configuration when using this subcommand. If the Keyid is a
nonzero integer, all outgoing packets to the remote server will have an
authentication field attached encrypted with this key. To specify no
authentication , enter Keyid as 0 or leave blank. The values
for Version can be 1, 2 or 3, with 3 as the default. The
prefer option indicates a preferred peer used primarily for clock
synchronization if possible. The preferred peer also determines the
validity of the PPS signal. If the preferred peer is suitable for
synchronization, so is the PPS signal.
|
| addserver
PeerAddress [ Keyid ] [ Version ] [
prefer ]
|
|
| Same as the addpeer subcommand, except that the operating mode
is client.
|
| addtrap
Address [ Port ] [ Interface ]
|
|
| Sets a trap for asynchronous messages at the specified address and port
number for sending messages with the specified local interface address.
If you do not specify the port number, the value defaults to 18447. If
you do not specify the interface address, the value defaults to the source
address of the local interface.
|
| authinfo
| Displays information concerning the authentication module, including
known keys and counts of encryptions and decryptions performed.
|
| broadcast
PeerAddress [ Keyid ] [ Version ]
|
|
| Same as the addpeer subcommand, except that the operating mode
is broadcast. The PeerAddress can be the broadcast address
of the local network or a multicast group address assigned to NTP
(224.0.1.1).
|
| clrtrap
Address [ Port ] [ Interface ]
|
|
| Clears a trap for asynchronous messages at the specified address and port
number for sending messages with the specified local interface address.
If you do not specify the port number, the value defaults to 18447. If
you do not specify the interface address, the value defaults to the source
address of the local interface.
|
| delrestrict
Address Mask [ ntpport ]
|
|
| Deletes the matching entry from the restrict list.
|
| disable
Option ...
| Disables various server options. Does not affect options not
mentioned. The enable subcommand describes the
options.
|
| enable
Option ...
| Enables various server options. Does not affect options not
mentioned. You can specify one or more of the following values for
Option:
- auth
- Causes the server to synchronize with unconfigured peers only if the peer
has been correctly authenticated using a trusted key and key
identifier. The default for this option is disable (off).
- bclient
- Causes the server to listen for a message from a broadcast or multicast
server, following which an association is automatically instantiated for that
server. The default for this argument is disable (off).
- monitor
- Enables the monitoring facility, with default enable (on).
- pll
- Enables the server to adjust its local clock, with default enable
(on). If not set, the local clock free-runs at its intrinsic time and
frequency offset. This option is useful when the local clock is
controlled by some other device or protocol and NTP is used only to provide
synchronization to other clients.
- stats
- Enables statistics facility filegen, with default enable (on).
|
| fudge
PeerAddress [ Time1 ] [ Time2 ] [
Stratum ] [ Refid ]
|
|
| Provides a way to set certain data for a reference clock.
Time1 and
Time2 are in fixed point seconds and used in some clock drivers as
calibration constants.
Stratum is a number in
the range zero to 15 and used to assign a nonstandard operating stratum to the
clock.
Refid is an ASCII
string in the range one to four characters and used to assign a nonstandard
reference identifier to the clock.
|
| monitor
yes | no
| Enables or disables the monitoring facility. A
monitor no subcommand followed by a
monitor yes subcommand is a good way of resetting the
packet counts.
|
| readkeys
| Purges the current set of authentication keys and obtains a new set by
rereading the keys file specified in the xntpd configuration
file. This allows you to change encryption keys without restarting the
server.
|
| reset
Module
| Clears the statistics counters in various modules of the server.
You can specify one or more of the following values for
Module: io, sys, mem,
timer, auth, allpeers.
|
| restrict
Address Mask Option ...
|
|
| Adds the values of Option to an existing restrict list entry,
or adds a new entry to the list with the specified Option.
The mask option defaults to 255.255.255.255,
meaning that Address is treated as the address of an individual
host. You can specify one or more of the following values for
Option:
- ignore
- Ignore all packets from hosts which match this entry. Does not
respond to queries nor time server polls.
- limited
- Specifies that these hosts are subject to client limitation from the same
net. Net in this context refers to the IP notion of net (class A, class
B, class C, etc.). Only accepts the first
client_limit hosts that have shown up at the server and that have
been active during the last client_limit_period seconds.
Rejects requests from other clients from the same net. Only takes into
account time request packets. Private, control, and broadcast packets
are not subject to client limitation and therefore do not contribute to client
count. The monitoring capability of the xntpd daemon keeps a
history of clients. When you use this option, monitoring remains
active. The default value for client_limit is 3. The
default value for client_limit_period is 3600 seconds.
- lowpriotrap
- Declare traps set by matching hosts to low priority status. The
server can maintain a limited number of traps (the current limit is 3),
assigned on a first come, first served basis, and denies service to later trap
requestors. This parameter modifies the assignment algorithm by
allowing later requests for normal priority traps to override low priority
traps.
- nomodify
- Ignore all NTP mode 6 and 7 packets which attempt to modify the state of
the server (run time reconfiguration). Permits queries which return
information.
- nopeer
- Provide stateless time service to polling hosts, but not to allocate peer
memory resources to these hosts.
- noquery
- SIgnore all NTP mode 6 and 7 packets (information queries and
configuration requests) from the source. Does not affect time
service.
- noserve
- Ignore NTP packets whose mode is not 6 or 7. This denies time
service, but permits queries.
- notrap
- Decline to provide mode 6 control message trap service to matching
hosts. The trap service is a subsystem of the mode 6 control message
protocol intended for use by remote event logging programs.
- notrust
- STreat these hosts normally in other respects, but never use them as
synchronization sources.
- ntpport
- Match the restriction entry only if the source port in the packet is the
standard NTP UDP port (123).
|
| setprecision
Precision
| Sets the precision which the server advertises.
Precision should be a negative integer in the range -4 through
-20.
|
| traps
| Displays the traps set in the server.
|
| trustkey
Keyid ...
| Adds one or more keys to the trusted key list. When you enable
authentication, authenticates peers with trusted time using a trusted
key.
|
| unconfig
PeerAddress [ Addr2 ] [ Addr3 ] [ Addr4
]
|
|
| Removes the configured bit from the specified peers. In many cases
deletes the peer association. When appropriate, however, the
association may persist in an unconfigured mode if the remote peer is willing
to continue on in this fashion.
|
| unrestrict
Address Mask Option ...
|
|
| Removes the specified options from the restrict list entry indicated by
Address and Mask. The restrict
subcommand describes the values for Option.
|
| untrustkey
Keyid ...
| Removes one or more keys from the trusted key list.
|
| /usr/sbin/xntpdc
| Contains the xntpdc command.
|
The ntpq, ntpdate,
and ntptrace commands.
The xntpd daemon.
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