Working in the financial world, the best practices is to have 4 ntp servers (if not using PTP). 1) You need 3 to determine the correct time (and detect bad tickers) 2) If you lose 1 of the 3 above, then you no longer can determine the correct time 3) Therefore with 4, you have redundancy. We have two Symmetricom Stratum 1 time servers synced via GPS with Rubidium oscillators, and two RHEL 6 servers running ntpd for our 4 servers. ---- Matthew Huff | 1 Manhattanville Rd Director of Operations | Purchase, NY 10577 OTA Management LLC | Phone: 914-460-4039 -----Original Message----- From: Roy [mailto:r.engehausen@gmail.com] Sent: Friday, February 7, 2014 10:23 AM To: nanog@nanog.org Subject: Re: Need trusted NTP Sources On 2/7/2014 3:35 AM, Saku Ytti wrote:
On (2014-02-06 21:14 -0500), Jay Ashworth wrote:
My usual practice is to set up two in house servers, each of which talks to:
And then point everyone in house to both of them, assuming they accept multiple server names. Two is worst possible amount of NTP servers to have. Either one fails and your timing is wrong, because you cannot vote false ticker. And chance of either of two failing is higher than one specific of them.
"A man with a watch knows what time it is. A man with two watches is never sure."