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From: michael butler <imb@scgt.oz.au>
Message-Id: <199601281401.BAA00989@asstdc.scgt.oz.au>
Subject: Re: ntp stuff?
To: mal@sophocles.algonet.se (Mats Lofkvist)
Date: Mon, 29 Jan 1996 01:01:19 +1100 (EST)
Cc: nate@sri.MT.net, hackers@FreeBSD.org
In-Reply-To: <199601281242.NAA25243@sophocles.algonet.se> from "Mats Lofkvist" at Jan 28, 96 01:42:11 pm
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Mats Lofkvist writes:

> ----/etc/ntp.conf----
> server 192.36.125.2          # sunic.sunet.se
> server 194.68.128.19 prefer  # Stockholm-DGIX.sunet.se
> 
> driftfile /etc/ntp.drift

To this you can add ..

server 127.127.1.0
fudge 127.127.1.0 stratum 10

 .. to cause the local clock to appear to a stratum 10 reference for those
times that an external reference is unavailable through link outages. This
is useful because things like wsntp used on Windoze will not synch to an
unsynched clock.

> # this is inoperative unless xntpd is enabled; NO to disable
> tickadjflags="-Aq"
> ...

> (I also had to set TIMER_FREQ in my config file to make ntp not lose sync
> after a few minutes due to too large drifts.)

I usually "tweak" it using something like ..

tickadjflags="-Aq -t 9998"

 .. which renders a clock with this sort of characteristic ..

asstdc:~ % /usr/sbin/xntpdc
xntpdc> sysi

 [ .. ]

root distance:        0.07654 s
root dispersion:      0.02525 s
reference ID:         [128.250.37.1]
reference time:       b4b5fcdb.52284000  Mon, Jan 29 1996  0:47:07.320
system flags:         pll monitor stats 
frequency:            80.000 ppm
stability:            54.296 ppm <--- a relative measure of "jitter"

xntpdc> lo
offset:               0.007506 s
frequency:            9.935 ppm <--- anything < 128ppm is OK
poll adjust:          24
watchdog timer:       254 s

The actual number used for tickadj (9998 above) is machine-specific and
derived by experimentation over many days ..

	michael