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