[158119] in North American Network Operators' Group
Re: NTP Issues Today
daemon@ATHENA.MIT.EDU (Neil Harris)
Wed Nov 21 07:59:12 2012
Date: Wed, 21 Nov 2012 12:58:38 +0000
From: Neil Harris <neil@tonal.clara.co.uk>
To: Ryan Malayter <malayter@gmail.com>
In-Reply-To: <C82FA00E-9022-4E70-939A-689F145DD459@gmail.com>
Cc: "<nanog@nanog.org>" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 21/11/12 12:34, Ryan Malayter wrote:
>
> On Nov 19, 2012, at 6:12 PM, "Scott Weeks" <surfer@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
