.\"	$NetBSD: ntptrace.8,v 1.2 1997/04/20 21:53:23 christos Exp $
.\" Converted from HTML to mandoc by Christos Zoulas <christos@netbsd.org>
.\"
.Dd April 17, 1997
.Dt NTPTRACE 8
.Os
.Sh NAME
.Nm ntptrace
.Nd trace a chain of NTP servers back to the primary
.Sh SYNOPSIS
.Nm
.Op Fl vdn
.Op Fl r Ar retries
.Op Fl t Ar timeout
.Ar 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 
.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 0.00192, synch distance 0.011, 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.
.Pp
The following options are available:
.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.
.Sh BUGS
This program makes no attempt to improve accuracy by doing multiple
samples.
.Sh AUTHOR
David L. Mills (mills@udel.edu)