freebsd man page for ntptrace

NTPTRACE(1)                                                   General Commands Manual                                                  NTPTRACE(1)

NAME
       ntptrace - trace a chain of NTP servers back to the primary source

SYNOPSIS
       ntptrace [ -m max_hops ] [ -n ]

DESCRIPTION
       ntptrace 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 localhost. Here is an example of the output from ntptrace:

       % 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
       measured  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 stratum is the server hop count to the primary source, while
       the synchronization distance is the estimated error relative to the primary source. These terms are precisely defined in RFC-1305.

OPTIONS
       -m max_hops
              Sets the number of server hops to follow (default = 99).

       -n     Turns off the printing of host names; instead, host IP addresses are given. This may be useful if a nameserver is down.

BUGS
       This program makes no attempt to improve accuracy by doing multiple samples.

Network Time Protocol                                            December 4, 2011                                                      NTPTRACE(1)