[AusNOG] NTP Best Current Practices Internet Draft

[Mark Smith]

Hi,

Saw the thread about NTP, and thought I'd send this IETF Internet
Draft on NTP BCPs.

Network Time Protocol Best Current Practices
https://tools.ietf.org/html/draft-ietf-ntp-bcp-12

It recommends is 4 or more separate NTP time sources, and diverse
reference clocks.

The reason to have a number of NTP time sources is that when the
device does, it can compare the time provided by each against the
others, and if one of them is proving inaccurate time, it can ignored
the bad time source.

The problem that occurred with 0.au.pool.ntp.org proving bad time
wouldn't have had an effect if the Windows domain controller had at
least 2 other NTP time sources.

In addition to the NTP pool servers, there are some other public NTP
time sources you can use

time.windows.com

time.apple.com

time-a.netgear.com
time-b.netgear.com
time-c.netgear.com
time-d.netgear.com
time-e.netgear.com
time-f.netgear.com
time-g.netgear.com
time-h.netgear.com

ntp1.dlink.com

Google also provide public NTP time servers, however they use a
different technique to deal with leap seconds (leap smear), so they
recommend against mixing them with NTP servers that don't use that
technique.

https://developers.google.com/time/