1.\" $NetBSD: ntptrace.8,v 1.2 2012/11/14 08:26:29 njoly Exp $ 2.\" Converted from HTML to mandoc by ntp-html2mdoc.pl 3.\" 4.Dd March 29, 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) 19server gets its time from, and follows the chain of NTP servers back to 20their master time source. If given no arguments, it starts with 21.Pa localhost . 22Here is an example of the output from 23.Nm : 24.Bd -literal 25% ntptrace 26localhost: stratum 4, offset 0.0019529, synch distance 0.144135 27server2ozo.com: stratum 2, offset 0.0124263, synch distance 0.115784 28usndh.edu: stratum 1, offset 0.0019298, synch distance 0.011993, refid 'WWVB' 29.Ed 30.Pp 31On each line, the fields are (left to right): the host name, the host stratum, 32the time offset between that host and the local host (as measured by 33.Nm 34; 35this is why it is not always zero for 36.Pa localhost 37), the host synchronization 38distance, and (only for stratum-1 servers) the reference clock ID. All 39times are given in seconds. Note that the stratum is the server hop count 40to the primary source, while the synchronization distance is the estimated 41error relative to the primary source. These terms are precisely defined 42in RFC-1305. 43.Sh OPTIONS 44.Bl -tag -width indent 45.It Fl d 46Turns on some debugging output. 47.It Fl n 48Turns off the printing of host names; instead, host IP addresses are given. 49This may be useful if a nameserver is down. 50.It Fl r Ar retries 51Sets the number of retransmission attempts for each host (default = 5). 52.It Fl t Ar timeout 53Sets the retransmission timeout (in seconds) (default = 2). 54.It Fl v 55Prints verbose information about the NTP servers. 56.El 57.Sh AUTHORS 58David L. Mills (mills@udel.edu) 59.Sh BUGS 60This program makes no attempt to improve accuracy by doing multiple samples. 61