Facebook (time.facebook.com) and Google (time.google.com) NTP services use anycast ( https://en.wikipedia.org/wiki/Anycast ) and have a number of NTP servers in unpublished locations. If all goes well NTP requests reach a nearby server. There is no guarantee.
Microsoft (time.windows.com) NTP servers use unicast. The IP addresses and locations of these servers have varied over time and are unpublished, as far as I know. The NTP pool ( https://www.ntppool.org/en/ ) may help find a nearby NTP server, but the locations are not guaranteed. IP pings (ICMP echo request/response) travel from the client to the terrestrial NTP server, not to the satellites. On Mon, Aug 24, 2020 at 6:39 AM Jakob Bohm <jb-use...@wisemo.com.invalid> wrote: > On 2020-08-24 12:51, Beth Connell wrote: > > Hi, > > I'm struggling to find any information on where the free NTP servers are > geographically based. In particular, I'm wondering where Facebook, Google, > Microsoft, etc are based within the UK. Just for curiousity, I'm wondering > how this affects any interference to my location. > > > > Thanks > > > > All NTP time is GMT (now named UTC, after HM government dropped the > ball). The only geographic factor is the "ping time" to the time > server, the servers that are the most distant (longest ping) are the > GPS and Galileo satellites, that are hundreds or thousands of km from > the receiver, and use their own (non-NTP) protocols to correct for the > delay. > > Another problem is if the NTP server is one of those that deliberately > return slightly wrong time before and after each leap second to "smooth > out" the leap, some of the companies you mention reportedly do that. > > > Enjoy > > Jakob > -- > Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com > Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10 > This public discussion message is non-binding and may contain errors. > WiseMo - Remote Service Management for PCs, Phones and Embedded > > _______________________________________________ > questions mailing list > questions@lists.ntp.org > http://lists.ntp.org/listinfo/questions > _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
