NTP Issues Today

Wed Nov 21 13:06:54 UTC 2012

Guys:

We were synchronized against multiple sources. Unfortunately the Navy NTP source contaminated multiple downstream sources. 

Unless you can trace all your sources, if these sources all have a root source you will break. 

Sid Rao | CTI Group | +1 (317) 262-4677

On Nov 21, 2012, at 8:01 AM, "Neil Harris" <neil at tonal.clara.co.uk> wrote:

> On 21/11/12 12:34, Ryan Malayter wrote:
>> 
>> On Nov 19, 2012, at 6:12 PM, "Scott Weeks" <surfer at mauigateway.com> wrote:
>> 
>>> Lesson learned: Use more than one NTP source.
>> The lesson is: use MORE THAN TWO diverse NTP sources.
>> 
>> A man with two watches has no idea what the time it actually is.
> 
> Per David Mills, from the discussion linked upthread, this should be FOUR OR MORE...
> 
> "Every critical server should have at least four sources, no two from the
> same organization and, as much as possible, reachable only via diverse,
> nonintersecting paths."
> 
> Four, so that the remaining three can reach consensus even if one fails.
> 
> -- Neil
> 
> 
> 