Date: Fri, 26 Jan 1996 01:55:25 -0600 (CST) From: mailing list account <lists@argus.flash.net> To: caj@tower.stc.housing.washington.edu (Craig Johnston) Cc: freebsd-questions@freebsd.org Subject: Re: good NTP servers Message-ID: <199601260755.BAA01748@argus.flash.net> In-Reply-To: <199601260214.SAA29011@tower.stc.housing.washington.edu> from "Craig Johnston" at Jan 25, 96 06:14:54 pm
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In reply: > > They work nice too : > > > > ntpdate -p 8 time.nist.gov > > 25 Jan 16:23:28 ntpdate: adjust time server 192.43.244.18 offset 0.015795 > > ntpdate -p 8 tick.usno.navy.mil > > 25 Jan 16:24:04 ntpdate: adjust time server 192.5.41.40 offset 0.013828 > > ntpdate -p 8 tock.usno.navy.mil > > 25 Jan 16:24:27 ntpdate: adjust time server 192.5.41.41 offset -0.002344 > > time.nist.gov is of course a stratum 1 server, and if the other 2 are > synced to it, they are stratum 2 servers. It is customary to _not_ sync > from a stratum 1 server unless a large number of other machines are syncing > from you, and then to get permission. It is also generally polite to get > permission / inform stratum 2 servers if you plan to use them. > > Also, if you are just using ntpdate to sync, and not xntpd, using a stratum > 1 server is kinda silly. Find a few nice stratum 2 and 3 servers and sync > from them. > > A nice list can be found at ftp.udel.edu somewhere in /pub/ntp -- it might > be in the xntpd distribution itself. Lots of nice stratum 2 servers to > sync to. please let me clarify my earlier statements... tick.usno.navy.mil and tock.usno.navy.mil are not network synchronized via xntpd to time.nist.gov... time.nist.gov is sync'ed to NIST Cesium clocks... tick.usno.navy.mil and tock.usno.navy.mil are sync'ed to Navy Cesium clocks, I am assuming [someone please correct me if I am wrong] that these clocks are sync'ed in a method similar to that described on pp 10 and 11 of NIST Special Pub 432, as the Cesium sources at the USNO are traceable to NIST. The method described on pg 10 is accurate to less than 100ns, this is utilizing GPS... this is pure assumption based on the fact that the Cesium Primary Standards in use at the USNO are tracable to NIST, and that NIST uses the GPS method as described to sync the Primary standards at WWV, WWVB, and WWVH. Since all three sites are using NIST tracable Cesium Primary Standards, I guess that would make all three sites stratum 1 servers... sorry folx... Jim -- All opinions expressed are mine, if you | "I will not be pushed, stamped, think otherwise, then go jump into turbid | briefed, debriefed, indexed, or radioactive waters and yell WAHOO !!! | numbered!" - #1, "The Prisoner" jbryant@argus.flash.net - FlashNet Communications - Ft. Worth, Texas
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