North America RegionNIST Internet Time ServersThese can be used as a alternate source for NTP server addresses.
These are U.S. based servers.
Other NTP severs maybe used for U.S. and Europe and Asia regionsWhen looking for NTP time servers, the "
NTP Pool" is available. This pool is a cluster of world wide voluntaries that provide that service to the community.
As of today there are 3646 time servers world wide in this pool. 2557 of
them are in Europe. And even 954 in North America!
The homepage of this project is
http://www.pool.ntp.org/enThere is plenty of information on the NTP homepage
http://www.ntp.org,
e.g. for public time servers at
http://support.ntp.org/bin/view/Servers/WebHome. At this page you can even search for time servers with your own criteria, like ones in your country or servers available via IPv6 for example.
They also provide information about the NTP pool at
http://support.ntp.org/bin/view/Servers/NTPPoolServers.
There you can see that the NTP pool is organized like a tree:
pool.ntp.org at the top (world), branching into larger sub-pools like
europe.pool.ntp.org or
north-america.pool.ntp.org . And from there into the country pools, like the German ones at
de.pool.ntp.org or the Swedish ones at
se.pool.ntp.org. Below that it divides into some more subgroups by pre-pending a number.
Independent from this, some companies provide their own public time servers. One of the most prominent ones is probably
time.windows.com, the time server pool of Microsoft that provides the time to all Windows computers with default settings still active. Apple also has there own, i.e.
time.euro.apple.com and there are probably plenty more.
Most ISPs provide their own time servers, too.
Thanks to "
nestolea" for his contribution and information to this sticky.