Richard B. Gilbert <rgilber...@comcast.net> wrote: > Rob wrote: >> Maynard <maynard7f...@gmail.com> wrote: >>> On 1/7/10, the date on our domain controller jumped to 12/7/10, and >>> was there for about 11 minutes before it reverted back to the current >>> date. At the time this happened, our NTP server was pointed to >>> pool.ntp.org. We also have a few Novell servers that were pointed to >>> the same IP addresses as our Server 2003 Domain Controller, and the >>> NTP server for our Novell network also jumped ahead. Are we the only >>> ones that had this issue on this day? Or are there others out there >>> that experienced the same problem on the 7th. Thanks >> >> This can happen any time. pool.ntp.org is a large collection of >> servers that joined a voluntary pool of servers. Any single server >> in this pool can send the wrong date and time if it likes to, or if >> there is an error. > <snip> >> It is better to use at least 3 different servers from the pool. I.e. >> use servernames 1.pool.ntp.org 2.pool.ntp.org 3.pool.ntp.org for 3 >> different servers. >> >> That way, of one fails or plays nasty games, your time will not be >> affected. > > Better still to use at least four servers, whether from the pool or not. > Using only three servers leaves you vulnerable; if one of them fails you > are left with two and no possibility of "voting one out" if one the > remaining servers fails, for it is written that a man with two clocks > can never be certain what time it is!
I am not going to play the game "it is better to use 25 servers because if you use 24 and 23 of them fail it leaves you vulnerable". _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
