ntpdc(8)ntpdc(8)Namentpdc - monitor operation of the NTP daemon, ntpd
Syntax
/usr/etc/ntpdc [ -n ][ -v ] host1 | IPaddress1 ...
Description
The command sends a query to the daemon running on each of the hosts
listed on the command line. The daemon on each responding host sends
information about the current calculated offset between its time and
the time of each of its NTP servers or peers. The command formats the
information on the standard output.
You can specify hosts by either host name or Internet address. The
hosts that you specify must either exist in the file, or in the master
database, if the database is being served to your system by BIND/Hesiod
or Yellow Pages. The command by default generates a terse, table-style
report. If you specify the option, the command generates a verbose
report.
Options-n Prints Internet addresses, instead of host names, of the servers
or peers. By default, the Internet addresses of the responding
hosts and the names of their servers or peers are printed.
-v Prints a verbose report for each of the servers or peers of the
responding host.
Examples
Terse Report:
The following is a typical terse report generated in response to the
command:
% /usr/etc/ntpdc 555.5.55.55
The host 555.5.55.55 is an NTP client, with the servers and specified
in its file. The information returned is about and
Address Strat Poll Reach Delay Offset Disp
(rem) (lcl)
.server1 555.5.55.55 1 64 377 53.0 -65.0 5.0
*server2 555.5.55.55 1 256 377 155.0 -4.0 16.0
+server3 555.5.55.55 2 64 377 16.0 -61.0 3.0
The fields are interpreted as follows:
- , + , . or *
A minus sign (-), plus sign (+), or dot (.) indicates a pre-con‐
figured peer (see the reference page). The asterisk (*) indi‐
cates which pre-configured peer (if any) is currently being used
for synchronization.
(rem) The remote host name or Internet address of a peer or server of
the responding host.
(lcl) The Internet address of the responding host that was specified
on the command line.
Strat The current operating stratum level of the peer or server.
Since the NTP hierarchy can change dynamically the stratum lev‐
els may change. Lower stratum levels correspond to higher accu‐
racy.
Poll Current polling interval in seconds for this peer or server.
Polling intervals change dynamically.
Reach Reachability in response to the last 8 polls (value of 8-bit
shift register with bits entering from the end furthest to the
right).
Delay The estimated round-trip delay in milliseconds for NTP message
exchanges between the responding host and this peer or server.
Delay is calculated from the previous 8 polls.
Offset The estimated offset between the peer or server's time and the
responding host's time in milliseconds. This value is calcu‐
lated from the previous 8 polls.
Disp The current estimated value of dispersion in milliseconds for
this peer's offset/delay pair.
Dispersion is used by the daemon in the clock selection algo‐
rithm. Increasing values of dispersion are associated with
decreasing quality of the estimate.
Verbose Report:
When the option is given, a verbose report for each of the servers or
peers of each of the hosts specified on the command line is generated.
The following is a typical verbose report generated in response to the
following command line:
% /usr/etc/ntpdc -v 111.11.111.11
Neighbor address 555.55.5.55 port:123 local address 111.11.1.11
Reach: 0377 stratum: 2, precision: -7
dispersion: 2.000000, flags: 1301, leap: 0
Reference clock ID: [22.22.2.22] timestamp: 7e5aa1a9.2add5d0b
hpoll: 10, ppoll: 10, timer: 1024, sent: 85 received: 90
Delay(ms) 20.00 20.00 28.00 29.00 20.00 39.00 29.00 28.00
Offset(ms) 5.00 6.00 5.00 -1.00-2.00 0.00 3.00 5.00
delay: 20.000000 offset: 5.000000 dsp 2.000000
--------------------------------------------------------------------
The fields are interpreted as follows:
Neighbor address
The address and port number of one NTP server, followed by the
Internet address of the responding host (local address).
Reach: Reachability in response to the last 8 polls (value of 8-bit
shift register with bits entering from the end furthest to the
right).
stratum:
The current operating stratum level of the peer or server.
Since the NTP hierarchy can change dynamically the stratum lev‐
els may change. Lower stratum levels correspond to higher accu‐
racy.
precision:
The precision of this clock, given in seconds as a power of 2.
If precision is equal to -7, that means that the precision is
2**-7, or 1/128 seconds. The daemon automatically determines
the precision of each clock based on the kernel variable
disp: The current estimated value of dispersion in milliseconds for
this peer's offset/delay pair. Dispersion is used by the daemon
in the clock selection algorithm. Increasing values of disper‐
sion are associated with decreasing quality of the estimate.
flags: nn
The parameter is used by the daemon clock selection process.
leap: flag
The leap second indicator. Non-zero if there is to be a leap
second inserted in the NTP timescale. The bits are set before
23:59 on the day of insertion and reset after 00:00 on the fol‐
lowing day.
Reference clock ID: address
If the NTP server is synchronized by a radio/satellite timecode
receiver, this field is or If the NTP server is the local refer‐
ence clock, this field is Finally, this field can be the of the
most accurate NTP server currently serving the responding host.
timestamp: nn
The local time, in hex-timestamp format, when the local clock of
the server was last updated.
hpoll: n
The host poll interval which is the maximum interval between
messages transmitted to the server, in seconds as a power of 2.
For example, a value of 6 indicates an interval of 64 seconds.
ppoll: n
The peer poll interval which is the maximum interval between
messages sent by the server, in seconds as a power of 2. For
example, a value of 6 indicates an interval of 64 seconds.
timer: nn
The current poll rate in seconds.
sent: nn
The number of NTP packets sent to this server by the responding
host.
received: nn
The number of NTP packets received from this server by the
responding host.
Delay and Offset
The round-trip delay and estimated clock offset for the last
eight NTP packet exchanges. If there are fewer than eight valid
samples, the delay field will be zero.
delay: est-delay offset: est-offset dsp: n
Estimated delay, offset, and dispersion calculated from the
above 8 samples. See RFC 1129 for how to calculate the esti‐
mated delay, offset, and dispersion.
Diagnostics
host1: connection refused
Check whether the daemon is running on
host2: unknown
The command cannot resolve the host name Check that exists in the file,
or that it exists in the master database, if the database is being
served by BIND/Hesiod or Yellow Pages.
If a server is listed in the host's file, but does not appear in the
report, it is possible that the daemon on the responding host can not
resolve the server names in the file. Check that the server exists in
the responding host's file or in the master database, if the database
is being served to the responding host by BIND/Hesiod or Yellow Pages.
See Alsontp.conf(5), ntp(8), ntpd(8)
RFC 1129—Internet Time Synchronization: the Network Time Protocol
Introduction to Networking and Distributed System Services
ntpdc(8)