[ntp:questions] Second attempt at GPS-18 based NTP server

David Lord snews at lordynet.org
Thu Feb 2 20:17:51 UTC 2012

David J Taylor wrote:
>> On NetBSD-5 with ntpd 4.2.6p5 the default is 64s.
> I wonder what expertise they have to select polling for reference 
> clocks? BTW: Paul has FreeBSD.
>> I've just added the "minpoll 4 maxpoll 4" back to my ntp.conf
>> as it could reduce the 30 usec offset blips I get when logs are
>> rotated.
> Agreed.
>> On my two pool servers I have named internet servers with
>> "minpoll 8 maxpoll 10 iburst" which gives reasonably fast
>> recovery from internet outages.
>> Temperature changes  here mean that on pcs that don't have
>> a PPS source "minpoll 10" just doesn't work and leads to
>> ntpd stepping the clock.
>> David
> As I have five stratum-1 servers here fed from four GPS receivers, I'm 
> hopeful that I won't need to reply on Internet servers.  The portable PC 
> I might take out and use Wi-Fi has the standard "minpoll 6 maxpoll 10 
> iburst" settings.
> Don't you link you other PCs to your stratum-1 server?  I do, with lines 
> like:
>  server  192.168.0.n  iburst  maxpoll 5  prefer # FreeBSD server
>  server  192.168.0.n  iburst  maxpoll 5 # Windows server
>  server  192.168.0.n  iburst  maxpoll 5 # Windows server

I only have a single pc with GPS source and some pcs on
lan  use that. I also have "tos minsane 3" which means
that the single GPS source isn't enough.

I've also had GPS blacked out along with MSF, for a few
months last year. Previous year and this year there's
not been a problem. From my location it's certainly not
possible to rely on radio signals.


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