mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-03 09:00:21 +00:00
77 lines
1.9 KiB
Groff
77 lines
1.9 KiB
Groff
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 6, 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 Ar server
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility 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
|
|
.Dq localhost .
|
|
.Pp
|
|
Here is an example of the output from
|
|
.Nm :
|
|
.Bd -literal
|
|
% 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'
|
|
.Ed
|
|
.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
|
|
.Dq 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
|
|
Turn on some debugging output.
|
|
.It Fl n
|
|
Turn off the printing of host names; instead, host IP addresses
|
|
are given.
|
|
This may be necessary if a nameserver is down.
|
|
.It Fl r Ar retries
|
|
Set the number of retransmission attempts for each host; the default is 5.
|
|
.It Fl t Ar timeout
|
|
Set the retransmission timeout (in seconds); the default is 2.
|
|
.It Fl v
|
|
Print verbose information about the NTP servers.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr ntpd 8 ,
|
|
.Xr ntpdc 8
|
|
.Rs
|
|
.%A D L Mills
|
|
.%T Network Time Protocol (Version 3)
|
|
.%O RFC1305
|
|
.Re
|
|
.Sh BUGS
|
|
This program makes no attempt to improve accuracy by doing multiple
|
|
samples.
|