Thanks, Jez. I'm pretty much ex-IT myself, these days.
On Aug 17, 2014 3:25 AM, "Jez Cunningham" <jez@xxxxxxxxxxxxxx> wrote:
> Good info Scott! I've bookmarked you as a trusted source ;-)
> ex-IT Jez (pursued by a bear?)
>
>
> On 17 August 2014 03:25, Scott Gomez <sgomez.baja@xxxxxxxxx> wrote:
>
> > Best practice is to get time sync from the nearest time server to you,
> and
> > not query the "source" directly for it. Time servers have a hierarchy,
> like
> > DNS servers, because of loading issues, and as turns out, most of the
> major
> > ISPs seem to provide this service from their DNS servers. Then you set
> one
> > machine in your network up to query the time servers directly, on fairly
> > long interval, and set all other machines on your network to query your
> > configured master machine. That's probably the best method for the
> average
> > person wanting accurate time service. Another way to do it would be to
> set
> > a network switch, or your router or firewall to be the master time server
> > for your home network, and point all other devices to it for time
> service,
> > where possible.
> >
> > Note that upper level time servers can and will block connection from
> > devices they determine to a) poll too often, b) not be sufficiently high
> in
> > the hierarchy to poll high-level servers directly, or c) be sending
> > malformed queries. Whether you know if you've been blocked is entirely up
> > to you to determine, which, on Windows machines, often meant not knowing
> at
> > all until you started getting bizarre behavior on downstream machines due
> > to being too far out of sync.
> >
> > Microsoft run a time server for the purpose. There are also ntp pool
> > servers that can be queried. See the (many!) notes and instructions
> > available via searching on "network time protocol" or "network time
> > service", but keep in mind that when it comes to use of critical internet
> > services like ntp, adherence to the RFCs are usually the "law" as far as
> > responsible system administrators are concerned. Relevant RFCs are
> numbers
> > 958, 1305 (version 3) and 5905 (version 4). Unlike application
> programmers
> > (who have quite accurately been referred to by Chris Trask as "cyber
> > toddlers") responsible for the user-facing software, Syadmins (like
> myself,
> > for instance) are a famously cranky lot, and tenacious in their pursuit
> of
> > up-time. See XKCD, here:
> >
> > http://www.xkcd.com/705/
> >
> > or the BOFH series:
> >
> > http://bofh.ntk.net/BOFH/
> >
> > In our defence, I will say that we come by our reputation honestly.
> >
> > Microsoft's note on use of Windows Time Service (which has been provided
> as
> > part of Windows since the XP days):
> >
> > http://support.microsoft.com/kb/307897
> >
> > Properly set up, it's accurate enough for most uses (including sniping
> bids
> > on Ebay, which I often used to do). It has been a long time since I
> delved
> > further into it, but I believe some versions (probably newer than XP?)
> even
> > have a means of compensating for drift rate, which is usually the largest
> > error factor in home PCs, which aren't notoriously stable when it comes
> to
> > time. NOTE: there are significant differences in setup between "flavors"
> > such as XP Home and XP Professional. I would assume that that's true as
> > well for WinVista, Win7, and Win8.
> >
> > Linux machines (and by extension, Macs, which use a very similar method)
> > are quite easy to configure to get time sync from a network source,
> > unless/until one needs extremely high accuracy. As far as I know, both
> have
> > a check box where it can be selected, and from then on it's usually
> > "automagic".
> >
> > ---
> > Scott
> >
> >
> > On Fri, Aug 15, 2014 at 11:02 AM, Chris Barker <ftog@xxxxxxxxxxxxxx>
> > wrote:
> >
> > > Thanks for more useful information, Ken.
> > >
> > > But you needn't worry about us in the UK: we get all our time from Big
> > > Ben, which is always on time.
> > >
> > > :-)
> > >
> > > Chris
> > >
> > > On 15 Aug 14, at 16:37, Ken Norton <ken@xxxxxxxxxxx> wrote:
> > >
> > > > Like seriously! Take a frequency band meant for Space-to-ground
> > > > transmission, immediately next to the GPS band (where the signal
> > > > strength is somewhere just above the universe's noise floor) and
> > > > instead repurpose it to ground-to-ground transmittions with high
> power
> > > > transmitters. It wasn't just cheap, inexpensive unfiltered GPS units
> > > > that suffered. During the tests, it was wiping out everything and the
> > > > GPS BITS clock receivers were getting completely toasted. But that
> > > > didn't influence the regulators. It took the threat of airplanes
> > > > falling out of the sky before anybody would listen. We faced
> > > > opposition that was mind-boggling.
> > > >
> > > > In almost every case, the NTP sites you are getting your clock
> updates
> > > > from are primary timed from a GPS timed BITS Clock system.
> > >
> > > --
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