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Google's public NTP servers?

I was struggling with finding a good set of low-ping NTP servers for use as upstream sources in the office. Using pool.ntp.org is great and all, but the rotating DNS entries aren't fabulous for Windows NTP clients (or really any NTP software except the reference ntpd implementation).

ntpd resolves a server hostname to an IP once at startup, and then sticks with that IP forever. Most other NTP clients honor DNS TTLs, and will follow the rotation of addresses returned by pool.ntp.org. This means Windows NTP client using the built-in Windows Time Service will actually be trying to sync to a moving set of target servers when pointed at a pool.ntp.org source. Fine for most client, but not great for servers trying to maintain stable timing for security and logging purposes.

I stumbled across this link referencing Google's ntp servers at hostname time[1-4].google.com. These servers support IPv4 and IPv6, and seem to be anycast just like Google's public DNS servers at 8.8.8.8. time…