1.\" 2.\" $FreeBSD$ 3.\" 4.Dd January 6, 2000 5.Dt NTPTRACE 8 6.Os 7.Sh NAME 8.Nm ntptrace 9.Nd "trace a chain of NTP servers back to the primary source" 10.Sh SYNOPSIS 11.Nm 12.Op Fl vdn 13.Op Fl r Ar retries 14.Op Fl t Ar timeout 15.Op Ar server 16.Sh DESCRIPTION 17The 18.Nm 19utility determines where a given Network Time Protocol (NTP) server gets 20its time from, and follows the chain of NTP servers back to their 21master time source. 22If given no arguments, it starts with 23.Dq localhost . 24.Pp 25Here is an example of the output from 26.Nm : 27.Bd -literal 28% ntptrace 29localhost: stratum 4, offset 0.0019529, synch distance 0.144135 30server2ozo.com: stratum 2, offset 0.0124263, synch distance 0.115784 31usndh.edu: stratum 1, offset 0.0019298, synch distance 0.011993, refid 'WWVB' 32.Ed 33.Pp 34On each line, the fields are (left to right): the host name, the 35host stratum, 36the time offset between that host and the local host 37(as measured by 38.Nm ; 39this is why it is not always zero for 40.Dq localhost ) , 41the host 42synchronization distance, 43and (only for stratum-1 servers) the reference clock ID. 44All times 45are given in seconds. 46Note that the stratum is the server hop count to the primary source, 47while the synchronization distance is the estimated error 48relative to the primary source. 49These terms are precisely defined in RFC 1305. 50.Pp 51The following options are available: 52.Bl -tag -width indent 53.It Fl d 54Turn on some debugging output. 55.It Fl n 56Turn off the printing of host names; instead, host IP addresses 57are given. 58This may be necessary if a nameserver is down. 59.It Fl r Ar retries 60Set the number of retransmission attempts for each host; the default is 5. 61.It Fl t Ar timeout 62Set the retransmission timeout (in seconds); the default is 2. 63.It Fl v 64Print verbose information about the NTP servers. 65.El 66.Sh SEE ALSO 67.Xr ntpd 8 , 68.Xr ntpdc 8 69.Rs 70.%A D L Mills 71.%T Network Time Protocol (Version 3) 72.%O RFC1305 73.Re 74.Sh BUGS 75This program makes no attempt to improve accuracy by doing multiple 76samples. 77