.\"	$NetBSD: ntptrace.8,v 1.2 2000/03/30 01:49:25 simonb Exp $
.\" Converted from HTML to mandoc by html-to-mdoc.pl
.\"
.Dd Mar 29, 2000
.Dt NTPTRACE 8
.Os
.Sh NAME
.Nm ntptrace
.Nd trace a chain of NTP servers back to the primary source
.Sh SYNOPSIS
.Nm
.Op Fl vdn
.Op Fl r Ar retries
.Op Fl t Ar timeout
.Op Fl server
.Sh DESCRIPTION
.Nm
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 
.Pa localhost .
Here is an example of the output from 
.Nm "" :
.Pp
.nf
% 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'
.fi
.Pp
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 
.Nm
;
this is why it is not always zero for
.Pa 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.
.Sh OPTIONS
.Bl -tag -width indent
.It Fl d
Turns on some debugging output.
.It Fl n
Turns off the printing of host names; instead, host IP addresses are given.
This may be useful if a nameserver is down.
.It Fl r Ar retries
Sets the number of retransmission attempts for each host (default = 5).
.It Fl t Ar timeout
Sets the retransmission timeout (in seconds) (default = 2).
.It Fl v
Prints verbose information about the NTP servers.
.El
.Sh BUGS
This program makes no attempt to improve accuracy by doing multiple samples. 
.Sh AUTHOR
David L. Mills (mills@udel.edu)