If you’re running NTP 4.2.8, there’s a new directive “pool” that regularly removes defunct servers and resolves new ones from a pool address.
If you want to run your own stratum 1 NTP server, I can recommend the LeoNTP<http://leontp.com/> which is relatively cheap [1]. You do need to have good GPS reception, but it runs off PoE so you can just run some ethernet near a window. I would still run NTP on your gateways and have them sync to it rather than having clients point directly at it. [1] I received mine free for stress-testing it in the public NTP pool, it has served 70,000 requests per second at times without missing a beat. -- James Andrewartha Network & Projects Engineer Christ Church Grammar School Claremont, Western Australia Ph. (08) 9442 1757 Mob. 0424 160 877 From: cisco-voip <[email protected]> on behalf of Charles Goldsmith <[email protected]> Date: Monday, 8 May 2017 at 10:52 pm To: "Haas, Neal" <[email protected]> Cc: "[email protected]" <[email protected]> Subject: Re: [cisco-voip] CCX and NTP To expand on this, I would point to your voice gateways with everything internal, then the voice gateways would either use an on-prem NTP server that is radio sync'd or one that Neal has advised. That way, everything is synced together with the same source. For UCCX and other apps, I point them to the UCM pub and the pub points to the voice gateways. I've seen a lot of people advise for pool.ntp.org<http://pool.ntp.org>, but that has bitten me. How often does an NTP process refresh from DNS? I suspect only on reboot or a restart of the NTP process. I've seen too many NTP servers go offline when using the pool addresses. Because of that, I've been sticking with .gov based NTP on the voice gateway. Ryan Huff, one thing about pointing to strata 1 servers, most of them have restrictions from what I've seen, while they work, they could block you for not being approved if you send too many requests. http://support.ntp.org/bin/view/Servers/StratumOneTimeServers has a list, and while many have open access listed, if you look at the details, they can still have restrictions. Just food for thought. On Mon, May 8, 2017 at 9:20 AM, Haas, Neal <[email protected]<mailto:[email protected]>> wrote: Get an on-prem NTP server, if you cant spend the money, use: time.nist.gov<http://time.nist.gov> global address for all servers Multiple locations utcnist.colorado.edu<http://utcnist.colorado.edu> 128.138.140.44 University of Colorado, Boulder utcnist2.colorado.edu<http://utcnist2.colorado.edu> 128.138.141.172 University of Colorado, Boulder time-nw.nist.gov<http://time-nw.nist.gov> 131.107.13.100 Microsoft, Redmond, Washington Really, anything with a GOV, or EDU should be good. By the way, you should NEVER, EVER, EVER (can’t stress this enough) a Windows Based NTP. Every place that I have went into and removed a Windows Time server, everything has worked better! Windows just cant do time. I went into a business with windows NTP, and the guy was checking time from about 100 NTP servers, his time was off by three minutes. Took it down to 3 and everything started to work. Thank You, Neal Haas From: cisco-voip [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Ben Amick Sent: Monday, May 8, 2017 7:12 AM To: [email protected]<mailto:[email protected]> Subject: [cisco-voip] CCX and NTP What do you guys use for NTP on your CCX hosts? I’ve been informed by TAC that “CCX does not support Windows based NTP” so I was thinking about just pointing NTP towards my CCM hosts – is that a valid scenario? I figure that since CCM is pretty much authoritative on everything for CCX as it is it wouldn’t be a problem? Ben Amick Telecom Analyst Confidentiality Note: This message is intended for use only by the individual or entity to which it is addressed and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient or the employee or agent responsible for delivering the message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and destroy the material in its entirety, whether electronic or hard copy. Thank you _______________________________________________ cisco-voip mailing list [email protected]<mailto:[email protected]> https://puck.nether.net/mailman/listinfo/cisco-voip
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