NTPTRACE(8) BSD System Manager's Manual NTPTRACE(8)
ntptrace -- trace a chain of NTP servers back to the primary source
ntptrace [-vdn] [-r retries] [-t timeout] [server]
The ntptrace utility determines where a given Network Time Protocol (NTP)
server gets its time from, and follows the chain of NTP servers back to
their master time source. If given no arguments, it starts with
Here is an example of the output from ntptrace:
localhost: stratum 4, offset 0.0019529, synch distance 0.144135
server2ozo.com: stratum 2, offset 0.0124263, synch distance 0.115784
usndh.edu: stratum 1, offset 0.0019298, synch distance 0.011993, refid 'WWVB'
On each line, the fields are (left to right): the host name, the host
stratum, the time offset between that host and the local host (as mea-
sured by ntptrace; this is why it is not always zero for ``localhost''),
the host synchronization distance, and (only for stratum-1 servers) the
reference clock ID. All times are given in seconds. Note that the stra-
tum is the server hop count to the primary source, while the synchroniza-
tion distance is the estimated error relative to the primary source.
These terms are precisely defined in RFC 1305.
The following options are available:
-d Turn on some debugging output.
-n Turn off the printing of host names; instead, host IP addresses
are given. This may be necessary if a nameserver is down.
Set the number of retransmission attempts for each host; the
default is 5.
Set the retransmission timeout (in seconds); the default is 2.
-v Print verbose information about the NTP servers.
D L Mills, Network Time Protocol (Version 3), RFC1305.
This program makes no attempt to improve accuracy by doing multiple sam-
BSD January 6, 2000 BSD